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Sample records for gastrocnemius myoelectric control

  1. Gastrocnemius Myoelectric Control of a Robotic Hip Exoskeleton Can Reduce the User's Lower-Limb Muscle Activities at Push Off

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    Lorenzo Grazi

    2018-02-01

    Full Text Available We present a novel assistive control strategy for a robotic hip exoskeleton for assisting hip flexion/extension, based on a proportional Electromyography (EMG strategy. The novelty of the proposed controller relies on the use of the Gastrocnemius Medialis (GM EMG signal instead of a hip flexor muscle, to control the hip flexion torque. This strategy has two main advantages: first, avoiding the placement of the EMG electrodes at the human–robot interface can reduce discomfort issues for the user and motion artifacts of the recorded signals; second, using a powerful signal for control, such as the GM, could improve the reliability of the control system. The control strategy has been tested on eight healthy subjects, walking with the robotic hip exoskeleton on the treadmill. We evaluated the controller performance and the effect of the assistance on muscle activities. The tuning of the assistance timing in the controller was subject dependent and varied across subjects. Two muscles could benefit more from the assistive strategy, namely the Rectus Femoris (directly assisted and the Tibialis Anterior (indirectly assisted. A significant correlation was found between the timing of the delivered assistance (i.e., synchronism with the biological hip torque, and reduction of the hip flexors muscular activity during walking; instead, no significant correlations were found for peak torque and peak power. Results suggest that the timing of the assistance is the most significant parameter influencing the effectiveness of the control strategy. The findings of this work could be important for future studies aimed at developing assistive strategies for walking assistance exoskeletons.

  2. Myoelectric Control Techniques for a Rehabilitation Robot

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    Alan Smith

    2011-01-01

    Full Text Available This work examines two different types of myoelectric control schemes for the purpose of rehabilitation robot applications. The first is a commonly used technique based on a Gaussian classifier. It is implemented in real time for healthy subjects in addition to a subject with Central Cord Syndrome (CCS. The myoelectric control scheme is used to control three degrees of freedom (DOF on a robot manipulator which corresponded to the robot's elbow joint, wrist joint, and gripper. The classes of motion controlled include elbow flexion and extension, wrist pronation and supination, hand grasping and releasing, and rest. Healthy subjects were able to achieve 90% accuracy. Single DOF controllers were first tested on the subject with CCS and he achieved 100%, 96%, and 85% accuracy for the elbow, gripper, and wrist controllers respectively. Secondly, he was able to control the three DOF controller at 68% accuracy. The potential applications for this scheme are rehabilitation and teleoperation. To overcome limitations in the pattern recognition based scheme, a second myoelectric control scheme is also presented which is trained using electromyographic (EMG data derived from natural reaching motions in the sagittal plane. This second scheme is based on a time delayed neural network (TDNN which has the ability to control multiple DOF at once. The controller tracked a subject's elbow and shoulder joints in the sagittal plane. Results showed an average error of 19° for the two joints. This myoelectric control scheme has the potential of being used in the development of exoskeleton and orthotic rehabilitation applications.

  3. Use of probabilistic weights to enhance linear regression myoelectric control.

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    Smith, Lauren H; Kuiken, Todd A; Hargrove, Levi J

    2015-12-01

    Clinically available prostheses for transradial amputees do not allow simultaneous myoelectric control of degrees of freedom (DOFs). Linear regression methods can provide simultaneous myoelectric control, but frequently also result in difficulty with isolating individual DOFs when desired. This study evaluated the potential of using probabilistic estimates of categories of gross prosthesis movement, which are commonly used in classification-based myoelectric control, to enhance linear regression myoelectric control. Gaussian models were fit to electromyogram (EMG) feature distributions for three movement classes at each DOF (no movement, or movement in either direction) and used to weight the output of linear regression models by the probability that the user intended the movement. Eight able-bodied and two transradial amputee subjects worked in a virtual Fitts' law task to evaluate differences in controllability between linear regression and probability-weighted regression for an intramuscular EMG-based three-DOF wrist and hand system. Real-time and offline analyses in able-bodied subjects demonstrated that probability weighting improved performance during single-DOF tasks (p linear regression control. Use of probability weights can improve the ability to isolate individual during linear regression myoelectric control, while maintaining the ability to simultaneously control multiple DOFs.

  4. Mechanical design and control of a new myoelectric hand prosthesis

    NARCIS (Netherlands)

    Peerdeman, B.; Stramigioli, Stefano; Hekman, Edsko E.G.; Brouwer, Dannis Michel; Misra, Sarthak

    2011-01-01

    The development of modern, myoelectrically controlled hand prostheses can be difficult, due to the many requirements its mechanical design and control system need to fulfill [1]. The hand should be controllable with few input signals, while being able to perform a wide range of motions. It should be

  5. Use of probabilistic weights to enhance linear regression myoelectric control

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    Smith, Lauren H.; Kuiken, Todd A.; Hargrove, Levi J.

    2015-12-01

    Objective. Clinically available prostheses for transradial amputees do not allow simultaneous myoelectric control of degrees of freedom (DOFs). Linear regression methods can provide simultaneous myoelectric control, but frequently also result in difficulty with isolating individual DOFs when desired. This study evaluated the potential of using probabilistic estimates of categories of gross prosthesis movement, which are commonly used in classification-based myoelectric control, to enhance linear regression myoelectric control. Approach. Gaussian models were fit to electromyogram (EMG) feature distributions for three movement classes at each DOF (no movement, or movement in either direction) and used to weight the output of linear regression models by the probability that the user intended the movement. Eight able-bodied and two transradial amputee subjects worked in a virtual Fitts’ law task to evaluate differences in controllability between linear regression and probability-weighted regression for an intramuscular EMG-based three-DOF wrist and hand system. Main results. Real-time and offline analyses in able-bodied subjects demonstrated that probability weighting improved performance during single-DOF tasks (p < 0.05) by preventing extraneous movement at additional DOFs. Similar results were seen in experiments with two transradial amputees. Though goodness-of-fit evaluations suggested that the EMG feature distributions showed some deviations from the Gaussian, equal-covariance assumptions used in this experiment, the assumptions were sufficiently met to provide improved performance compared to linear regression control. Significance. Use of probability weights can improve the ability to isolate individual during linear regression myoelectric control, while maintaining the ability to simultaneously control multiple DOFs.

  6. Evaluation of Linear Regression Simultaneous Myoelectric Control Using Intramuscular EMG.

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    Smith, Lauren H; Kuiken, Todd A; Hargrove, Levi J

    2016-04-01

    The objective of this study was to evaluate the ability of linear regression models to decode patterns of muscle coactivation from intramuscular electromyogram (EMG) and provide simultaneous myoelectric control of a virtual 3-DOF wrist/hand system. Performance was compared to the simultaneous control of conventional myoelectric prosthesis methods using intramuscular EMG (parallel dual-site control)-an approach that requires users to independently modulate individual muscles in the residual limb, which can be challenging for amputees. Linear regression control was evaluated in eight able-bodied subjects during a virtual Fitts' law task and was compared to performance of eight subjects using parallel dual-site control. An offline analysis also evaluated how different types of training data affected prediction accuracy of linear regression control. The two control systems demonstrated similar overall performance; however, the linear regression method demonstrated improved performance for targets requiring use of all three DOFs, whereas parallel dual-site control demonstrated improved performance for targets that required use of only one DOF. Subjects using linear regression control could more easily activate multiple DOFs simultaneously, but often experienced unintended movements when trying to isolate individual DOFs. Offline analyses also suggested that the method used to train linear regression systems may influence controllability. Linear regression myoelectric control using intramuscular EMG provided an alternative to parallel dual-site control for 3-DOF simultaneous control at the wrist and hand. The two methods demonstrated different strengths in controllability, highlighting the tradeoff between providing simultaneous control and the ability to isolate individual DOFs when desired.

  7. Myoelectric control of prosthetic hands: state-of-the-art review

    Directory of Open Access Journals (Sweden)

    Geethanjali P

    2016-07-01

    Full Text Available Purushothaman Geethanjali School of Electrical Engineering Department of Control and Automation VIT University, Vellore, Tamil Nadu, India Abstract: Myoelectric signals (MES have been used in various applications, in particular, for identification of user intention to potentially control assistive devices for amputees, orthotic devices, and exoskeleton in order to augment capability of the user. MES are also used to estimate force and, hence, torque to actuate the assistive device. The application of MES is not limited to assistive devices, and they also find potential applications in teleoperation of robots, haptic devices, virtual reality, and so on. The myoelectric control-based prosthetic hand aids to restore activities of daily living of amputees in order to improve the self-esteem of the user. All myoelectric control-based prosthetic hands may not have similar operations and exhibit variation in sensing input, deciphering the signals, and actuating prosthetic hand. Researchers are focusing on improving the functionality of prosthetic hand in order to suit the user requirement with the different operating features. The myoelectric control differs in operation to accommodate various external factors. This article reviews the state of the art of myoelectric prosthetic hand, giving description of each control strategy. Keywords: EMG, assistive device, amputee, myoelectric control, electric powered, body ­powered, bioelectric signal control

  8. Context-dependent adaptation improves robustness of myoelectric control for upper-limb prostheses

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    Patel, Gauravkumar K.; Hahne, Janne M.; Castellini, Claudio; Farina, Dario; Dosen, Strahinja

    2017-10-01

    Objective. Dexterous upper-limb prostheses are available today to restore grasping, but an effective and reliable feed-forward control is still missing. The aim of this work was to improve the robustness and reliability of myoelectric control by using context information from sensors embedded within the prosthesis. Approach. We developed a context-driven myoelectric control scheme (cxMYO) that incorporates the inference of context information from proprioception (inertial measurement unit) and exteroception (force and grip aperture) sensors to modulate the outputs of myoelectric control. Further, a realistic evaluation of the cxMYO was performed online in able-bodied subjects using three functional tasks, during which the cxMYO was compared to a purely machine-learning-based myoelectric control (MYO). Main results. The results demonstrated that utilizing context information decreased the number of unwanted commands, improving the performance (success rate and dropped objects) in all three functional tasks. Specifically, the median number of objects dropped per round with cxMYO was zero in all three tasks and a significant increase in the number of successful transfers was seen in two out of three functional tasks. Additionally, the subjects reported better user experience. Significance. This is the first online evaluation of a method integrating information from multiple on-board prosthesis sensors to modulate the output of a machine-learning-based myoelectric controller. The proposed scheme is general and presents a simple, non-invasive and cost-effective approach for improving the robustness of myoelectric control.

  9. Game-Based Rehabilitation for Myoelectric Prosthesis Control.

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    Prahm, Cosima; Vujaklija, Ivan; Kayali, Fares; Purgathofer, Peter; Aszmann, Oskar C

    2017-02-09

    A high number of upper extremity myoelectric prosthesis users abandon their devices due to difficulties in prosthesis control and lack of motivation to train in absence of a physiotherapist. Virtual training systems, in the form of video games, provide patients with an entertaining and intuitive method for improved muscle coordination and improved overall control. Complementary to established rehabilitation protocols, it is highly beneficial for this virtual training process to start even before receiving the final prosthesis, and to be continued at home for as long as needed. The aim of this study is to evaluate (1) the short-term effects of a commercially available electromyographic (EMG) system on controllability after a simple video game-based rehabilitation protocol, and (2) different input methods, control mechanisms, and games. Eleven able-bodied participants with no prior experience in EMG control took part in this study. Participants were asked to perform a surface EMG test evaluating their provisional maximum muscle contraction, fine accuracy and isolation of electrode activation, and endurance control over at least 300 seconds. These assessments were carried out (1) in a Pregaming session before interacting with three EMG-controlled computer games, (2) in a Postgaming session after playing the games, and (3) in a Follow-Up session two days after the gaming protocol to evaluate short-term retention rate. After each game, participants were given a user evaluation survey for the assessment of the games and their input mechanisms. Participants also received a questionnaire regarding their intrinsic motivation (Intrinsic Motivation Inventory) at the end of the last game. Results showed a significant improvement in fine accuracy electrode activation (Pgames when collecting items and facing challenging game play. Most upper limb amputees use a 2-channel myoelectric prosthesis control. This study demonstrates that this control can be effectively trained by

  10. Locomotor Adaptation by Transtibial Amputees Walking With an Experimental Powered Prosthesis Under Continuous Myoelectric Control.

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    Huang, Stephanie; Wensman, Jeffrey P; Ferris, Daniel P

    2016-05-01

    Lower limb amputees can use electrical activity from their residual muscles for myoelectric control of a powered prosthesis. The most common approach for myoelectric control is a finite state controller that identifies behavioral states and discrete changes in motor tasks. An alternative approach to state-based myoelectric control is continuous proportional myoelectric control where ongoing electrical activity has a proportional relationship to the prosthetic joint torque or power. To test the potential of continuous proportional myoelectric control for powered lower limb prostheses, we recruited five unilateral transtibial amputees to walk on a treadmill with an experimental powered prosthesis. Subjects walked using the powered prosthesis with and without visual feedback of their control signal in real time. Amputee subjects were able to adapt their residual muscle activation patterns to alter prosthetic ankle mechanics when we provided visual feedback of their myoelectric control signal in real time. During walking with visual feedback, subjects significantly increased their peak prosthetic ankle power ( p = 0.02, ANOVA) and positive work ( p = 0.02, ANOVA) during gait above their prescribed prosthesis values. However, without visual feedback, the subjects did not increase their peak ankle power during push off. These results show that amputee users were able to volitionally alter their prosthesis mechanics during walking, but only when given an explicit goal for their residual muscle motor commands. Future studies that examine the motor and learning capabilities of lower limb amputees using their residual muscles for continuous proportional myoelectric control are needed to determine the viability of integrating continuous high-level control with existing finite state prosthetic controllers.

  11. Elucidating Sensorimotor Control Principles with Myoelectric Musculoskeletal Models

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    Sarah E. Goodman

    2017-11-01

    Full Text Available There is an old saying that you must walk a mile in someone's shoes to truly understand them. This mini-review will synthesize and discuss recent research that attempts to make humans “walk a mile” in an artificial musculoskeletal system to gain insight into the principles governing human movement control. In this approach, electromyography (EMG is used to sample human motor commands; these commands serve as inputs to mathematical models of muscular dynamics, which in turn act on a model of skeletal dynamics to produce a simulated motor action in real-time (i.e., the model's state is updated fast enough produce smooth motion without noticeable transitions; Manal et al., 2002. In this mini-review, these are termed myoelectric musculoskeletal models (MMMs. After a brief overview of typical MMM design and operation principles, the review will highlight how MMMs have been used for understanding human sensorimotor control and learning by evoking apparent alterations in a user's biomechanics, neural control, and sensory feedback experiences.

  12. Model and experiments to optimize co-adaptation in a simplified myoelectric control system

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    Couraud, M.; Cattaert, D.; Paclet, F.; Oudeyer, P. Y.; de Rugy, A.

    2018-04-01

    Objective. To compensate for a limb lost in an amputation, myoelectric prostheses use surface electromyography (EMG) from the remaining muscles to control the prosthesis. Despite considerable progress, myoelectric controls remain markedly different from the way we normally control movements, and require intense user adaptation. To overcome this, our goal is to explore concurrent machine co-adaptation techniques that are developed in the field of brain-machine interface, and that are beginning to be used in myoelectric controls. Approach. We combined a simplified myoelectric control with a perturbation for which human adaptation is well characterized and modeled, in order to explore co-adaptation settings in a principled manner. Results. First, we reproduced results obtained in a classical visuomotor rotation paradigm in our simplified myoelectric context, where we rotate the muscle pulling vectors used to reconstruct wrist force from EMG. Then, a model of human adaptation in response to directional error was used to simulate various co-adaptation settings, where perturbations and machine co-adaptation are both applied on muscle pulling vectors. These simulations established that a relatively low gain of machine co-adaptation that minimizes final errors generates slow and incomplete adaptation, while higher gains increase adaptation rate but also errors by amplifying noise. After experimental verification on real subjects, we tested a variable gain that cumulates the advantages of both, and implemented it with directionally tuned neurons similar to those used to model human adaptation. This enables machine co-adaptation to locally improve myoelectric control, and to absorb more challenging perturbations. Significance. The simplified context used here enabled to explore co-adaptation settings in both simulations and experiments, and to raise important considerations such as the need for a variable gain encoded locally. The benefits and limits of extending this

  13. Fully embedded myoelectric control for a wearable robotic hand orthosis.

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    Ryser, Franziska; Butzer, Tobias; Held, Jeremia P; Lambercy, Olivier; Gassert, Roger

    2017-07-01

    To prevent learned non-use of the affected hand in chronic stroke survivors, rehabilitative training should be continued after discharge from the hospital. Robotic hand orthoses are a promising approach for home rehabilitation. When combined with intuitive control based on electromyography, the therapy outcome can be improved. However, such systems often require extensive cabling, experience in electrode placement and connection to external computers. This paper presents the framework for a stand-alone, fully wearable and real-time myoelectric intention detection system based on the Myo armband. The hard and software for real-time gesture classification were developed and combined with a routine to train and customize the classifier, leading to a unique ease of use. The system including training of the classifier can be set up within less than one minute. Results demonstrated that: (1) the proposed algorithm can classify five gestures with an accuracy of 98%, (2) the final system can online classify three gestures with an accuracy of 94.3% and, in a preliminary test, (3) classify three gestures from data acquired from mildly to severely impaired stroke survivors with an accuracy of over 78.8%. These results highlight the potential of the presented system for electromyography-based intention detection for stroke survivors and, with the integration of the system into a robotic hand orthosis, the potential for a wearable platform for all day robot-assisted home rehabilitation.

  14. Control of word processing environment using myoelectric signals

    Czech Academy of Sciences Publication Activity Database

    Pošusta, Antonín; Sporka, A. J.; Poláček, O.; Rudolf, Š.; Otáhal, Jakub

    2015-01-01

    Roč. 9, č. 4 (2015), s. 299-311 ISSN 1783-7677 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : assistive technology * text input * myoelectric signals * user study Subject RIV: FH - Neurology Impact factor: 1.017, year: 2015

  15. Online human training of a myoelectric prosthesis controller via actor-critic reinforcement learning.

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    Pilarski, Patrick M; Dawson, Michael R; Degris, Thomas; Fahimi, Farbod; Carey, Jason P; Sutton, Richard S

    2011-01-01

    As a contribution toward the goal of adaptable, intelligent artificial limbs, this work introduces a continuous actor-critic reinforcement learning method for optimizing the control of multi-function myoelectric devices. Using a simulated upper-arm robotic prosthesis, we demonstrate how it is possible to derive successful limb controllers from myoelectric data using only a sparse human-delivered training signal, without requiring detailed knowledge about the task domain. This reinforcement-based machine learning framework is well suited for use by both patients and clinical staff, and may be easily adapted to different application domains and the needs of individual amputees. To our knowledge, this is the first my-oelectric control approach that facilitates the online learning of new amputee-specific motions based only on a one-dimensional (scalar) feedback signal provided by the user of the prosthesis. © 2011 IEEE

  16. Exploring optimal myoelectric feature indices for forearm control strategy using robust principal component analysis.

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    Kanoga, Suguru; Murai, Akihiko; Tada, Mitsunori

    2017-07-01

    Forearm movements realize various functions needed in daily life. For reproduction of the motion sequences, active myoelectric devices have been developed. Usually, feature indices are extracted from observed signals in control strategy; however, the optimal combination of indices is still unclear. This paper introduces sparsity-inducing penalty term in principal component analysis (PCA) to explore optimal myoelectric feature indices. An electromyographic database including seven forearm movements from 30 subjects was used for performance comparison. Linear classifier with sparse features showed best performance (7.86±3.82% error rate) that was significantly better than linear classifier with all features because of recovering low rank matrix in original data. Furthermore, the sparse features had a large contribution of underlying data structure with less number of principal components than PCA. Root-mean-square, time-domain features, autoregressive coefficients, and Histogram purported to be important in projected feature space; therefore, the feature indices are important to myoelectric strategies.

  17. Effects of prosthesis use on the capability to control myoelectric robotic prosthetic hands.

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    Atzori, Manfredo; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Muller, Henning

    2015-08-01

    The natural control of robotic prosthetic hands with non-invasive techniques is still a challenge: myoelectric prostheses currently give some control capabilities; the application of pattern recognition techniques is promising and recently started to be applied in practice but still many questions are open in the field. In particular, the effects of clinical factors on movement classification accuracy and the capability to control myoelectric prosthetic hands are analyzed in very few studies. The effect of regularly using prostheses on movement classification accuracy has been previously studied, showing differences between users of myoelectric and cosmetic prostheses. In this paper we compare users of myoelectric and body-powered prostheses and intact subjects. 36 machine-learning methods are applied on 6 amputees and 40 intact subjects performing 40 movements. Then, statistical analyses are performed in order to highlight significant differences between the groups of subjects. The statistical analyses do not show significant differences between the two groups of amputees, while significant differences are obtained between amputees and intact subjects. These results constitute new information in the field and suggest new interpretations to previous hypotheses, thus adding precious information towards natural control of robotic prosthetic hands.

  18. Robust EMG sensing system based on data fusion for myoelectric control of a robotic arm.

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    López, Natalia M; di Sciascio, Fernando; Soria, Carlos M; Valentinuzzi, Max E

    2009-02-25

    Myoelectric control of a robotic manipulator may be disturbed by failures due to disconnected electrodes, interface impedance changes caused by movements, problems in the recording channel and other various noise sources. To correct these problems, this paper presents two fusing techniques, Variance Weighted Average (VWA) and Decentralized Kalman Filter (DKF), both based on the myoelectric signal variance as selecting criterion. Tested in five volunteers, a redundant arrangement was obtained with two pairs of electrodes for each recording channel. The myoelectric signals were electronically amplified, filtered and digitalized, while the processing, fusion algorithms and control were implemented in a personal computer under MATLAB environment and in a Digital Signal Processor (DSP). The experiments used an industrial robotic manipulator BOSCH SR-800, type SCARA, with four degrees of freedom; however, only the first joint was used to move the end effector to a desired position, the latter obtained as proportional to the EMG amplitude. Several trials, including disconnecting and reconnecting one electrode and disturbing the signal with synthetic noise, were performed to test the fusion techniques. The results given by VWA and DKF were transformed into joint coordinates and used as command signals to the robotic arm. Even though the resultant signal was not exact, the failure was ignored and the joint reference signal never exceeded the workspace limits. The fault robustness and safety characteristics of a myoelectric controlled manipulator system were substantially improved. The proposed scheme prevents potential risks for the operator, the equipment and the environment. Both algorithms showed efficient behavior. This outline could be applied to myoelectric control of prosthesis, or assistive manipulators to better assure the system functionality when electrode faults or noisy environment are present.

  19. Robust EMG sensing system based on data fusion for myoelectric control of a robotic arm

    Directory of Open Access Journals (Sweden)

    Soria Carlos M

    2009-02-01

    Full Text Available Abstract Background Myoelectric control of a robotic manipulator may be disturbed by failures due to disconnected electrodes, interface impedance changes caused by movements, problems in the recording channel and other various noise sources. To correct these problems, this paper presents two fusing techniques, Variance Weighted Average (VWA and Decentralized Kalman Filter (DKF, both based on the myoelectric signal variance as selecting criterion. Methods Tested in five volunteers, a redundant arrangement was obtained with two pairs of electrodes for each recording channel. The myoelectric signals were electronically amplified, filtered and digitalized, while the processing, fusion algorithms and control were implemented in a personal computer under MATLAB® environment and in a Digital Signal Processor (DSP. The experiments used an industrial robotic manipulator BOSCH SR-800, type SCARA, with four degrees of freedom; however, only the first joint was used to move the end effector to a desired position, the latter obtained as proportional to the EMG amplitude. Results Several trials, including disconnecting and reconnecting one electrode and disturbing the signal with synthetic noise, were performed to test the fusion techniques. The results given by VWA and DKF were transformed into joint coordinates and used as command signals to the robotic arm. Even though the resultant signal was not exact, the failure was ignored and the joint reference signal never exceeded the workspace limits. Conclusion The fault robustness and safety characteristics of a myoelectric controlled manipulator system were substantially improved. The proposed scheme prevents potential risks for the operator, the equipment and the environment. Both algorithms showed efficient behavior. This outline could be applied to myoelectric control of prosthesis, or assistive manipulators to better assure the system functionality when electrode faults or noisy environment are present.

  20. Motion Normalized Proportional Control for Improved Pattern Recognition-Based Myoelectric Control.

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    Scheme, Erik; Lock, Blair; Hargrove, Levi; Hill, Wendy; Kuruganti, Usha; Englehart, Kevin

    2014-01-01

    This paper describes two novel proportional control algorithms for use with pattern recognition-based myoelectric control. The systems were designed to provide automatic configuration of motion-specific gains and to normalize the control space to the user's usable dynamic range. Class-specific normalization parameters were calculated using data collected during classifier training and require no additional user action or configuration. The new control schemes were compared to the standard method of deriving proportional control using a one degree of freedom Fitts' law test for each of the wrist flexion/extension, wrist pronation/supination and hand close/open degrees of freedom. Performance was evaluated using the Fitts' law throughput value as well as more descriptive metrics including path efficiency, overshoot, stopping distance and completion rate. The proposed normalization methods significantly outperformed the incumbent method in every performance category for able bodied subjects (p < 0.001) and nearly every category for amputee subjects. Furthermore, one proposed method significantly outperformed both other methods in throughput (p < 0.0001), yielding 21% and 40% improvement over the incumbent method for amputee and able bodied subjects, respectively. The proposed control schemes represent a computationally simple method of fundamentally improving myoelectric control users' ability to elicit robust, and controlled, proportional velocity commands.

  1. Comparative study of state-of-the-art myoelectric controllers for multigrasp prosthetic hands.

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    Segil, Jacob L; Controzzi, Marco; Weir, Richard F ff; Cipriani, Christian

    2014-01-01

    A myoelectric controller should provide an intuitive and effective human-machine interface that deciphers user intent in real-time and is robust enough to operate in daily life. Many myoelectric control architectures have been developed, including pattern recognition systems, finite state machines, and more recently, postural control schemes. Here, we present a comparative study of two types of finite state machines and a postural control scheme using both virtual and physical assessment procedures with seven nondisabled subjects. The Southampton Hand Assessment Procedure (SHAP) was used in order to compare the effectiveness of the controllers during activities of daily living using a multigrasp artificial hand. Also, a virtual hand posture matching task was used to compare the controllers when reproducing six target postures. The performance when using the postural control scheme was significantly better (p machines during the physical assessment when comparing within-subject averages using the SHAP percent difference metric. The virtual assessment results described significantly greater completion rates (97% and 99%) for the finite state machines, but the movement time tended to be faster (2.7 s) for the postural control scheme. Our results substantiate that postural control schemes rival other state-of-the-art myoelectric controllers.

  2. Comparative study of wavelet denoising in myoelectric control applications.

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    Sharma, Tanu; Veer, Karan

    2016-01-01

    Here, the wavelet analysis has been investigated to improve the quality of myoelectric signal before use in prosthetic design. Effective Surface Electromyogram (SEMG) signals were estimated by first decomposing the obtained signal using wavelet transform and then analysing the decomposed coefficients by threshold methods. With the appropriate choice of wavelet, it is possible to reduce interference noise effectively in the SEMG signal. However, the most effective wavelet for SEMG denoising is chosen by calculating the root mean square value and signal power values. The combined results of root mean square value and signal power shows that wavelet db4 performs the best denoising among the wavelets. Furthermore, time domain and frequency domain methods were applied for SEMG signal analysis to investigate the effect of muscle-force contraction on the signal. It was found that, during sustained contractions, the mean frequency (MNF) and median frequency (MDF) increase as muscle force levels increase.

  3. Knee Angle Estimation Algorithm for Myoelectric Control of Active Transfemoral Prostheses

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    Delis, Alberto López; de Carvalho, João Luiz Azevedo; Da Rocha, Adson Ferreira; de Oliveira Nascimento, Francisco Assis; Borges, Geovany Araújo

    This paper presents a bioinstrumentation system for the acquisition and pre-processing of surface electromyographic (SEMG) signals, and a knee angle estimation algorithm for control of active transfemoral leg prostheses, using methods for feature extraction and classification of myoelectric signal patterns. The presented microcontrolled bioinstrumentation system is capable of recording up to four SEMG channels, and one electrogoniometer channel. The proposed neural myoelectric controller algorithm is capable of predicting the intended knee joint angle from the measured SEMG signals. The algorithm is designed in three stages: feature extraction, using auto-regressive model and amplitude histogram; feature projection, using self organizing maps; and pattern classification, using a Levenberg-Marquardt neural network. The use of SEMG signals and additional mechanical information such as that provided by the electrogoniometer may improve precision in the control of leg prostheses. Preliminary results are presented.

  4. Real-time myoelectric control of a multi-fingered hand prosthesis using principal components analysis

    Directory of Open Access Journals (Sweden)

    Matrone Giulia C

    2012-06-01

    Full Text Available Abstract Background In spite of the advances made in the design of dexterous anthropomorphic hand prostheses, these sophisticated devices still lack adequate control interfaces which could allow amputees to operate them in an intuitive and close-to-natural way. In this study, an anthropomorphic five-fingered robotic hand, actuated by six motors, was used as a prosthetic hand emulator to assess the feasibility of a control approach based on Principal Components Analysis (PCA, specifically conceived to address this problem. Since it was demonstrated elsewhere that the first two principal components (PCs can describe the whole hand configuration space sufficiently well, the controller here employed reverted the PCA algorithm and allowed to drive a multi-DoF hand by combining a two-differential channels EMG input with these two PCs. Hence, the novelty of this approach stood in the PCA application for solving the challenging problem of best mapping the EMG inputs into the degrees of freedom (DoFs of the prosthesis. Methods A clinically viable two DoFs myoelectric controller, exploiting two differential channels, was developed and twelve able-bodied participants, divided in two groups, volunteered to control the hand in simple grasp trials, using forearm myoelectric signals. Task completion rates and times were measured. The first objective (assessed through one group of subjects was to understand the effectiveness of the approach; i.e., whether it is possible to drive the hand in real-time, with reasonable performance, in different grasps, also taking advantage of the direct visual feedback of the moving hand. The second objective (assessed through a different group was to investigate the intuitiveness, and therefore to assess statistical differences in the performance throughout three consecutive days. Results Subjects performed several grasp, transport and release trials with differently shaped objects, by operating the hand with the myoelectric

  5. Design and validation of a morphing myoelectric hand posture controller based on principal component analysis of human grasping.

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    Segil, Jacob L; Weir, Richard F ff

    2014-03-01

    An ideal myoelectric prosthetic hand should have the ability to continuously morph between any posture like an anatomical hand. This paper describes the design and validation of a morphing myoelectric hand controller based on principal component analysis of human grasping. The controller commands continuously morphing hand postures including functional grasps using between two and four surface electromyography (EMG) electrodes pairs. Four unique maps were developed to transform the EMG control signals in the principal component domain. A preliminary validation experiment was performed by 10 nonamputee subjects to determine the map with highest performance. The subjects used the myoelectric controller to morph a virtual hand between functional grasps in a series of randomized trials. The number of joints controlled accurately was evaluated to characterize the performance of each map. Additional metrics were studied including completion rate, time to completion, and path efficiency. The highest performing map controlled over 13 out of 15 joints accurately.

  6. Learning to walk with an adaptive gain proportional myoelectric controller for a robotic ankle exoskeleton.

    Science.gov (United States)

    Koller, Jeffrey R; Jacobs, Daniel A; Ferris, Daniel P; Remy, C David

    2015-11-04

    Robotic ankle exoskeletons can provide assistance to users and reduce metabolic power during walking. Our research group has investigated the use of proportional myoelectric control for controlling robotic ankle exoskeletons. Previously, these controllers have relied on a constant gain to map user's muscle activity to actuation control signals. A constant gain may act as a constraint on the user, so we designed a controller that dynamically adapts the gain to the user's myoelectric amplitude. We hypothesized that an adaptive gain proportional myoelectric controller would reduce metabolic energy expenditure compared to walking with the ankle exoskeleton unpowered because users could choose their preferred control gain. We tested eight healthy subjects walking with the adaptive gain proportional myoelectric controller with bilateral ankle exoskeletons. The adaptive gain was updated each stride such that on average the user's peak muscle activity was mapped to maximal power output of the exoskeleton. All subjects participated in three identical training sessions where they walked on a treadmill for 50 minutes (30 minutes of which the exoskeleton was powered) at 1.2 ms(-1). We calculated and analyzed metabolic energy consumption, muscle recruitment, inverse kinematics, inverse dynamics, and exoskeleton mechanics. Using our controller, subjects achieved a metabolic reduction similar to that seen in previous work in about a third of the training time. The resulting controller gain was lower than that seen in previous work (β=1.50±0.14 versus a constant β=2). The adapted gain allowed users more total ankle joint power than that of unassisted walking, increasing ankle power in exchange for a decrease in hip power. Our findings indicate that humans prefer to walk with greater ankle mechanical power output than their unassisted gait when provided with an ankle exoskeleton using an adaptive controller. This suggests that robotic assistance from an exoskeleton can allow

  7. Stable Myoelectric Control of a Hand Prosthesis using Non-Linear Incremental Learning

    Directory of Open Access Journals (Sweden)

    Arjan eGijsberts

    2014-02-01

    Full Text Available Stable myoelectric control of hand prostheses remains an open problem. The only successful human-machine interface is surface electromyography, typically allowing control of a few degrees of freedom. Machine learning techniques may have the potential to remove these limitations, but their performance is thus far inadequate: myoelectric signals change over time under the influence of various factors, deteriorating control performance. It is therefore necessary, in the standard approach, to regularly retrain a new model from scratch.We hereby propose a non-linear incremental learning method in which occasional updates with a modest amount of novel training data allow continual adaptation to the changes in the signals. In particular, Incremental Ridge Regression and an approximation of the Gaussian Kernel known as Random Fourier Features are combined to predict finger forces from myoelectric signals, both finger-by-finger and grouped in grasping patterns.We show that the approach is effective and practically applicable to this problem by first analyzing its performance while predicting single-finger forces. Surface electromyography and finger forces were collected from 10 intact subjects during four sessions spread over two different days; the results of the analysis show that small incremental updates are indeed effective to maintain a stable level of performance.Subsequently, we employed the same method on-line to teleoperate a humanoid robotic arm equipped with a state-of-the-art commercial prosthetic hand. The subject could reliably grasp, carry and release everyday-life objects, enforcing stable grasping irrespective of the signal changes, hand/arm movements and wrist pronation and supination.

  8. An Upper-Limb Power-Assist Exoskeleton Using Proportional Myoelectric Control

    Science.gov (United States)

    Tang, Zhichuan; Zhang, Kejun; Sun, Shouqian; Gao, Zenggui; Zhang, Lekai; Yang, Zhongliang

    2014-01-01

    We developed an upper-limb power-assist exoskeleton actuated by pneumatic muscles. The exoskeleton included two metal links: a nylon joint, four size-adjustable carbon fiber bracers, a potentiometer and two pneumatic muscles. The proportional myoelectric control method was proposed to control the exoskeleton according to the user's motion intention in real time. With the feature extraction procedure and the classification (back-propagation neural network), an electromyogram (EMG)-angle model was constructed to be used for pattern recognition. Six healthy subjects performed elbow flexion-extension movements under four experimental conditions: (1) holding a 1-kg load, wearing the exoskeleton, but with no actuation and for different periods (2-s, 4-s and 8-s periods); (2) holding a 1-kg load, without wearing the exoskeleton, for a fixed period; (3) holding a 1-kg load, wearing the exoskeleton, but with no actuation, for a fixed period; (4) holding a 1-kg load, wearing the exoskeleton under proportional myoelectric control, for a fixed period. The EMG signals of the biceps brachii, the brachioradialis, the triceps brachii and the anconeus and the angle of the elbow were collected. The control scheme's reliability and power-assist effectiveness were evaluated in the experiments. The results indicated that the exoskeleton could be controlled by the user's motion intention in real time and that it was useful for augmenting arm performance with neurological signal control, which could be applied to assist in elbow rehabilitation after neurological injury. PMID:24727501

  9. An upper-limb power-assist exoskeleton using proportional myoelectric control.

    Science.gov (United States)

    Tang, Zhichuan; Zhang, Kejun; Sun, Shouqian; Gao, Zenggui; Zhang, Lekai; Yang, Zhongliang

    2014-04-10

    We developed an upper-limb power-assist exoskeleton actuated by pneumatic muscles. The exoskeleton included two metal links: a nylon joint, four size-adjustable carbon fiber bracers, a potentiometer and two pneumatic muscles. The proportional myoelectric control method was proposed to control the exoskeleton according to the user's motion intention in real time. With the feature extraction procedure and the classification (back-propagation neural network), an electromyogram (EMG)-angle model was constructed to be used for pattern recognition. Six healthy subjects performed elbow flexion-extension movements under four experimental conditions: (1) holding a 1-kg load, wearing the exoskeleton, but with no actuation and for different periods (2-s, 4-s and 8-s periods); (2) holding a 1-kg load, without wearing the exoskeleton, for a fixed period; (3) holding a 1-kg load, wearing the exoskeleton, but with no actuation, for a fixed period; (4) holding a 1-kg load, wearing the exoskeleton under proportional myoelectric control, for a fixed period. The EMG signals of the biceps brachii, the brachioradialis, the triceps brachii and the anconeus and the angle of the elbow were collected. The control scheme's reliability and power-assist effectiveness were evaluated in the experiments. The results indicated that the exoskeleton could be controlled by the user's motion intention in real time and that it was useful for augmenting arm performance with neurological signal control, which could be applied to assist in elbow rehabilitation after neurological injury.

  10. Application of real-time machine learning to myoelectric prosthesis control: A case series in adaptive switching.

    Science.gov (United States)

    Edwards, Ann L; Dawson, Michael R; Hebert, Jacqueline S; Sherstan, Craig; Sutton, Richard S; Chan, K Ming; Pilarski, Patrick M

    2016-10-01

    Myoelectric prostheses currently used by amputees can be difficult to control. Machine learning, and in particular learned predictions about user intent, could help to reduce the time and cognitive load required by amputees while operating their prosthetic device. The goal of this study was to compare two switching-based methods of controlling a myoelectric arm: non-adaptive (or conventional) control and adaptive control (involving real-time prediction learning). Case series study. We compared non-adaptive and adaptive control in two different experiments. In the first, one amputee and one non-amputee subject controlled a robotic arm to perform a simple task; in the second, three able-bodied subjects controlled a robotic arm to perform a more complex task. For both tasks, we calculated the mean time and total number of switches between robotic arm functions over three trials. Adaptive control significantly decreased the number of switches and total switching time for both tasks compared with the conventional control method. Real-time prediction learning was successfully used to improve the control interface of a myoelectric robotic arm during uninterrupted use by an amputee subject and able-bodied subjects. Adaptive control using real-time prediction learning has the potential to help decrease both the time and the cognitive load required by amputees in real-world functional situations when using myoelectric prostheses. © The International Society for Prosthetics and Orthotics 2015.

  11. A MYOELECTRIC PROSTHETIC ARM CONTROLLED BY A SENSOR-ACTUATOR LOOP

    Directory of Open Access Journals (Sweden)

    Patrik Kutílek

    2014-06-01

    Full Text Available This paper describes new methods and systems designed for application in upper extremity prostheses. An artificial upper limb with this system is a robot arm controlled by EMG signals and a set of sensors. The new multi-sensor system is based on ultrasonic sensors, infrared sensors, Hall-effect sensors, a CO2 sensor and a relative humidity sensor. The multi-sensor system is used to update a 3D map of objects in the robot’s environment, or it directly sends information about the environment to the control system of the myoelectric arm. Occupancy grid mapping is used to build a 3D map of the robot’s environment. The multi-sensor system can identify the distance of objects in 3D space, and the information from the system is used in a 3D map to identify potential collisions or a potentially dangerous environment, which could damage the prosthesis or the user. Information from the sensors and from the 3D map is evaluated using a fuzzy expert system. The control system of the myoelectric prosthetic arm can choose an adequate reaction on the basis of information from the fuzzy expert system. The systems and methods were designed and verified using MatLab/Simulink. They are aimed for use as assistive technology for disabled people.

  12. Control Capabilities of Myoelectric Robotic Prostheses by Hand Amputees: A Scientific Research and Market Overview.

    Science.gov (United States)

    Atzori, Manfredo; Müller, Henning

    2015-01-01

    Hand amputation can dramatically affect the capabilities of a person. Cortical reorganization occurs in the brain, but the motor and somatosensorial cortex can interact with the remnant muscles of the missing hand even many years after the amputation, leading to the possibility to restore the capabilities of hand amputees through myoelectric prostheses. Myoelectric hand prostheses with many degrees of freedom are commercially available and recent advances in rehabilitation robotics suggest that their natural control can be performed in real life. The first commercial products exploiting pattern recognition to recognize the movements have recently been released, however the most common control systems are still usually unnatural and must be learned through long training. Dexterous and naturally controlled robotic prostheses can become reality in the everyday life of amputees but the path still requires many steps. This mini-review aims to improve the situation by giving an overview of the advancements in the commercial and scientific domains in order to outline the current and future chances in this field and to foster the integration between market and scientific research.

  13. Control Capabilities of Myoelectric Robotic Prostheses by Hand Amputees: A Scientific Research and Market Overview

    Directory of Open Access Journals (Sweden)

    Manfredo eAtzori

    2015-11-01

    Full Text Available Hand amputation can dramatically affect the capabilities of a person. Cortical reorganization occurs in the brain, but the motor and somatosensorial cortex can interact with the remnant muscles of the missing hand even many years after the amputation, leading to the possibility to restore the capabilities of hand amputees through myoelectric prostheses. Myoelectric hand prostheses with many degrees of freedom are commercially available and recent advances in rehabilitation robotics suggest that their natural control can be performed in real life. The first commercial products exploiting pattern recognition to recognize the movements have recently been released, however the most common control systems are still usually unnatural and must be learned through long training. Dexterous and naturally controlled robotic prostheses can become reality in the everyday life of amputees but the path still requires many steps. This mini-review aims to improve the situation by giving an overview of the advancements in the commercial and scientific domains in order to outline the current and future chances in this field and to foster the integration between market and scientific research.

  14. IMU-Based Wrist Rotation Control of a Transradial Myoelectric Prosthesis.

    Science.gov (United States)

    Bennett, Daniel A; Goldfarb, Michael

    2018-02-01

    This paper describes a control method intended to facilitate improved control of a myoelectric prosthesis containing a wrist rotator. Rather than exclusively utilizing electromyogram (EMG) for the control of all myoelectric components (e.g., a hand and a wrist), the proposed controller utilizes inertial measurement (from six-axis inertial measurement unit (IMU)) to sense upper arm abduction/adduction, and uses this input to command a wrist rotation velocity. As such, the controller essentially substitutes shoulder abduction/adduction in place of agonist/antagonist EMG to control wrist angular velocity, which preserves EMG for control of the hand (or other arm components). As a preliminary assessment of efficacy, the control method was implemented on a transradial prosthesis prototype with a powered wrist rotator and hand, and experimentally assessed on five able-bodied subjects who wore the prototype using an able-bodied adaptor and one transradial amputee subject while performing assessments representative of activities of daily living. The assessments compared the (timed) performance of the combined EMG/ IMU-based control method with a (conventional) sequential EMG control approach. Results of the assessment indicate that the able-bodied subjects were able to perform the tasks 33% faster on average with the EMG/IMU-based method, relative to a conventional sequential EMG method. The same assessment was subsequently conducted using a single transradial amputee subject, which resulted in similar performance trends, although with a somewhat lessened effect size-specifically, the amputee subject was on average 22% faster in performing tasks with the IMU-based controller.

  15. Assessment of Myoelectric Controller Performance and Kinematic Behavior of a Novel Soft Synergy-Inspired Robotic Hand for Prosthetic Applications.

    Science.gov (United States)

    Fani, Simone; Bianchi, Matteo; Jain, Sonal; Pimenta Neto, José Simões; Boege, Scott; Grioli, Giorgio; Bicchi, Antonio; Santello, Marco

    2016-01-01

    Myoelectric artificial limbs can significantly advance the state of the art in prosthetics, since they can be used to control mechatronic devices through muscular activity in a way that mimics how the subjects used to activate their muscles before limb loss. However, surveys indicate that dissatisfaction with the functionality of terminal devices underlies the widespread abandonment of prostheses. We believe that one key factor to improve acceptability of prosthetic devices is to attain human likeness of prosthesis movements, a goal which is being pursued by research on social and human-robot interactions. Therefore, to reduce early abandonment of terminal devices, we propose that controllers should be designed so as to ensure effective task accomplishment in a natural fashion. In this work, we have analyzed and compared the performance of three types of myoelectric controller algorithms based on surface electromyography to control an underactuated and multi-degrees of freedom prosthetic hand, the SoftHand Pro. The goal of the present study was to identify the myoelectric algorithm that best mimics the native hand movements. As a preliminary step, we first quantified the repeatability of the SoftHand Pro finger movements and identified the electromyographic recording sites for able-bodied individuals with the highest signal-to-noise ratio from two pairs of muscles, i.e., flexor digitorum superficialis/extensor digitorum communis, and flexor carpi radialis/extensor carpi ulnaris. Able-bodied volunteers were then asked to execute reach-to-grasp movements, while electromyography signals were recorded from flexor digitorum superficialis/extensor digitorum communis as this was identified as the muscle pair characterized by high signal-to-noise ratio and intuitive control. Subsequently, we tested three myoelectric controllers that mapped electromyography signals to position of the SoftHand Pro. We found that a differential electromyography-to-position mapping ensured the

  16. Designing and Manufacturing an Electrical Control System for Myoelectric Transradial Prothesis

    Directory of Open Access Journals (Sweden)

    Farhad Tabatabaei-Ghomsheh

    2006-07-01

    Full Text Available Objective: The goal of this study was to record the Electromyogram (EMG signal from the biceps and triceps muscles utilizing two individual channels to control an EMG driven myoelectric prosthesis. Materials & Methods: To achieve the study goal a system for recording and processing the signal was designed and fabricated. Based on recorded signals from biceps and triceps muscles, a successful system was developed to control a powered prosthesis. Results: According to the results of this study it was revealed that utilizing the average amount signal is a very successful way to obtain the control signal. Conclusion: Since the amplitude and frequency of the EMG signal has not yet been defined and sometime there are some unwanted electrical activities on the skin, prosthetic control is rather difficult for the users. Additionally, in IAV domain, no distinct border between strong and week contractions was obtained after conducted tests.

  17. Time-division multiplexing for myoelectric closed-loop control using electrotactile feedback.

    Science.gov (United States)

    Dosen, Strahinja; Schaeffer, Marie-Caroline; Farina, Dario

    2014-09-15

    Restoring sensory feedback in myoelectric prostheses is still an open challenge. Closing the loop might lead to a more effective utilization and better integration of these systems into the body scheme of the user. Electrotactile stimulation can be employed to transmit the feedback information to the user, but it represents a strong interference to the recording of the myoelectric signals that are used for control. Time-division multiplexing (TDM) can be applied to avoid this interference by performing the stimulation and recording in dedicated, non-overlapping time windows. A closed-loop compensatory tracking task with myocontrol and electrotactile stimulation was used to investigate how the duration of the feedback window (FW) influences the ability to perceive the feedback information and react with an appropriate control action. Nine subjects performed eight trials with continuous recording and contralateral feedback (CONT-CLT) and TDM with ispilateral stimulation and recording using the FW of 40 ms (TDM40), 100 ms (TDM100) and 300 ms (TDM300). The tracking quality was evaluated by comparing the reference and generated trajectories using cross-correlation coefficient (CCCOEF), time delay, root mean square tracking error, and the amount of overshoot. The control performance in CONT-CLT was the best in all the outcome measures. The overall worst performance was obtained using TDM with the shortest FW (TDM40). There was no significant difference between TDM100 and TDM300, and the quality of tracking in these two conditions was high (CCCOEF ~ 0.95). The results demonstrated that FW duration is indeed an important parameter in TDM, which appears to have an optimal value. Among the tested cases, the FW duration of 100 ms seems to be the best trade-off between the quality of perception and a limited command update rate. This study represents the first systematic evaluation of a TDM-based approach for closing the loop using electrotactile feedback in myoelectric

  18. Channel selection for simultaneous and proportional myoelectric prosthesis control of multiple degrees-of-freedom

    Science.gov (United States)

    Hwang, Han-Jeong; Hahne, Janne Mathias; Müller, Klaus-Robert

    2014-10-01

    Objective. Recent studies have shown the possibility of simultaneous and proportional control of electrically powered upper-limb prostheses, but there has been little investigation on optimal channel selection. The objective of this study is to find a robust channel selection method and the channel subsets most suitable for simultaneous and proportional myoelectric prosthesis control of multiple degrees-of-freedom (DoFs). Approach. Ten able-bodied subjects and one person with congenital upper-limb deficiency took part in this study, and performed wrist movements with various combinations of two DoFs (flexion/extension and radial/ulnar deviation). During the experiment, high density electromyographic (EMG) signals and the actual wrist angles were recorded with an 8 × 24 electrode array and a motion tracking system, respectively. The wrist angles were estimated from EMG features with ridge regression using the subsets of channels chosen by three different channel selection methods: (1) least absolute shrinkage and selection operator (LASSO), (2) sequential feature selection (SFS), and (3) uniform selection (UNI). Main results. SFS generally showed higher estimation accuracy than LASSO and UNI, but LASSO always outperformed SFS in terms of robustness, such as noise addition, channel shift and training data reduction. It was also confirmed that about 95% of the original performance obtained using all channels can be retained with only 12 bipolar channels individually selected by LASSO and SFS. Significance. From the analysis results, it can be concluded that LASSO is a promising channel selection method for accurate simultaneous and proportional prosthesis control. We expect that our results will provide a useful guideline to select optimal channel subsets when developing clinical myoelectric prosthesis control systems based on continuous movements with multiple DoFs.

  19. Robust extraction of basis functions for simultaneous and proportional myoelectric control via sparse non-negative matrix factorization.

    Science.gov (United States)

    Lin, Chuang; Wang, Binghui; Jiang, Ning; Farina, Dario

    2018-04-01

    This paper proposes a novel simultaneous and proportional multiple degree of freedom (DOF) myoelectric control method for active prostheses. The approach is based on non-negative matrix factorization (NMF) of surface EMG signals with the inclusion of sparseness constraints. By applying a sparseness constraint to the control signal matrix, it is possible to extract the basis information from arbitrary movements (quasi-unsupervised approach) for multiple DOFs concurrently. In online testing based on target hitting, able-bodied subjects reached a greater throughput (TP) when using sparse NMF (SNMF) than with classic NMF or with linear regression (LR). Accordingly, the completion time (CT) was shorter for SNMF than NMF or LR. The same observations were made in two patients with unilateral limb deficiencies. The addition of sparseness constraints to NMF allows for a quasi-unsupervised approach to myoelectric control with superior results with respect to previous methods for the simultaneous and proportional control of multi-DOF. The proposed factorization algorithm allows robust simultaneous and proportional control, is superior to previous supervised algorithms, and, because of minimal supervision, paves the way to online adaptation in myoelectric control.

  20. Robust extraction of basis functions for simultaneous and proportional myoelectric control via sparse non-negative matrix factorization

    Science.gov (United States)

    Lin, Chuang; Wang, Binghui; Jiang, Ning; Farina, Dario

    2018-04-01

    Objective. This paper proposes a novel simultaneous and proportional multiple degree of freedom (DOF) myoelectric control method for active prostheses. Approach. The approach is based on non-negative matrix factorization (NMF) of surface EMG signals with the inclusion of sparseness constraints. By applying a sparseness constraint to the control signal matrix, it is possible to extract the basis information from arbitrary movements (quasi-unsupervised approach) for multiple DOFs concurrently. Main Results. In online testing based on target hitting, able-bodied subjects reached a greater throughput (TP) when using sparse NMF (SNMF) than with classic NMF or with linear regression (LR). Accordingly, the completion time (CT) was shorter for SNMF than NMF or LR. The same observations were made in two patients with unilateral limb deficiencies. Significance. The addition of sparseness constraints to NMF allows for a quasi-unsupervised approach to myoelectric control with superior results with respect to previous methods for the simultaneous and proportional control of multi-DOF. The proposed factorization algorithm allows robust simultaneous and proportional control, is superior to previous supervised algorithms, and, because of minimal supervision, paves the way to online adaptation in myoelectric control.

  1. A comparison of the real-time controllability of pattern recognition to conventional myoelectric control for discrete and simultaneous movements.

    Science.gov (United States)

    Young, Aaron J; Smith, Lauren H; Rouse, Elliott J; Hargrove, Levi J

    2014-01-10

    Myoelectric control has been used for decades to control powered upper limb prostheses. Conventional, amplitude-based control has been employed to control a single prosthesis degree of freedom (DOF) such as closing and opening of the hand. Within the last decade, new and advanced arm and hand prostheses have been constructed that are capable of actuating numerous DOFs. Pattern recognition control has been proposed to control a greater number of DOFs than conventional control, but has traditionally been limited to sequentially controlling DOFs one at a time. However, able-bodied individuals use multiple DOFs simultaneously, and it may be beneficial to provide amputees the ability to perform simultaneous movements. In this study, four amputees who had undergone targeted motor reinnervation (TMR) surgery with previous training using myoelectric prostheses were configured to use three control strategies: 1) conventional amplitude-based myoelectric control, 2) sequential (one-DOF) pattern recognition control, 3) simultaneous pattern recognition control. Simultaneous pattern recognition was enabled by having amputees train each simultaneous movement as a separate motion class. For tasks that required control over just one DOF, sequential pattern recognition based control performed the best with the lowest average completion times, completion rates and length error. For tasks that required control over 2 DOFs, the simultaneous pattern recognition controller performed the best with the lowest average completion times, completion rates and length error compared to the other control strategies. In the two strategies in which users could employ simultaneous movements (conventional and simultaneous pattern recognition), amputees chose to use simultaneous movements 78% of the time with simultaneous pattern recognition and 64% of the time with conventional control for tasks that required two DOF motions to reach the target. These results suggest that when amputees are given the

  2. The reality of myoelectric prostheses: Understanding what makes these devices difficult for some users to control

    Directory of Open Access Journals (Sweden)

    Alix Chadwell

    2016-08-01

    Full Text Available Users of myoelectric prostheses can often find them difficult to control. This can lead to passive-use of the device or total rejection, which can have detrimental effects on the contralateral limb due to overuse.Current clinically available prostheses are ‘open loop’ systems, and although considerable effort has been focused on developing biofeedback to close the loop, there is evidence from laboratory-based studies that other factors, notably improving predictability of response, may be as, if not more, important. Interestingly, despite a large volume of research aimed at improving myoelectric prostheses, it is not currently known which aspect of clinically available systems has the greatest impact on overall functionality and everyday usage. A protocol has therefore been designed to assess EMG skill of the user and predictability of the prosthesis response as significant parts of the control chain, and to relate these to functionality and everyday usage. Here we present the protocol and results from early pilot work.A set of experiments has been developed. Firstly to characterize user skill in generating the required level of EMG signal, as well as the speed with which users are able to make the decision to activate the appropriate muscles. Secondly, to measure unpredictability introduced at the skin-electrode interface, in order to understand the effects of the socket mounted electrode fit under different loads on the variability of time taken for the prosthetic hand to respond.To evaluate prosthesis user functionality, four different outcome measures are assessed. Using a simple upper limb functional task prosthesis users are assessed for (1 success of task completion, (2 task duration, (3 quality of movement, and (4 gaze behavior. To evaluate everyday usage away from the clinic, the symmetricity of their real-world arm use is assessed using activity monitoring.These methods will later be used to assess a prosthesis user cohort, to

  3. Assessment of Myoelectric Controller Performance and Kinematic Behavior of a Novel Soft Synergy-inspired Robotic Hand for Prosthetic Applications

    Directory of Open Access Journals (Sweden)

    Simone Fani

    2016-10-01

    Full Text Available Myoelectric-artificial limbs can significantly advance the state of the art in prosthetics, since they can be used to control mechatronic devices through muscular activity in a way that mimics how the subjects used to activate their muscles before limb loss. However, surveys indicate that dissatisfaction with the functionality of terminal devices underlies the widespread abandonment of prostheses. We believe that one key factor to improve acceptability of prosthetic devices is to attain human-likeness of prosthesis movements, a goal which is being pursued by research on social and human-robot interactions. Therefore, to reduce early abandonment of terminal devices, we propose that controllers should be designed such as to ensure effective task accomplishment in a natural fashion. In this work, we have analyzed and compared the performance of three types of myoelectric controller algorithms based on surface electromyography to control an under-actuated and multi-degrees of freedom prosthetic hand, the SoftHand Pro. The goal of the present study was to identify the myoelectric algorithm that best mimics the native hand movements. As a preliminary step, we first quantified the repeatability of the SoftHand Pro finger movements and identified the electromyographic recording sites for able-bodied individuals with the highest signal-to-noise ratio from two pairs of muscles, i.e. flexor digitorum superficialis/extensor digitorum communis, and flexor carpi radialis/extensor carpi ulnaris. Able-bodied volunteers were then asked to execute reach-to-grasp movements, while electromyography signals were recorded from flexor digitorum superficialis/extensor digitorum communis as this was identified as the muscle pair characterized by high signal-to-noise ratio and intuitive control. Subsequently, we tested three myoelectric controllers that mapped electromyography signals to position of the SoftHand Pro. We found that a differential electromyography

  4. Two-dimensional myoelectric control of a robotic arm for upper limb amputees

    International Nuclear Information System (INIS)

    Lopez Celani, Natalia M; Soria, Carlos M; Orosco, Eugenio C; Di Sciascio, Fernando A; Valentinuzzi, Max E

    2007-01-01

    Rehabilitation engineering and medicine have become integral and significant parts of health care services, particularly and unfortunately in the last three or four decades, because of wars, terrorism and large number of car accidents. Amputees show a high rate of rejection to wear prosthetic devices, often because of lack of an adequate period of adaptation. A robotic arm may appear as a good preliminary stage. To test the hypothesis, myoelectric signals from two upper limb amputees and from four normal volunteers were fed, via adequate electronic conditioning and using MATLAB, to an industrial robotic arm. Proportional strength control was used for two degrees of freedom (x-y plane) by means of eight signal features of control (four traditional statistics plus energy, integral of the absolute value, Willison's amplitude, waveform length and envelope) for comparison purposes, and selecting the best of them as final reference. Patients easily accepted the system and learned in short time how to operate it. Results were encouraging so that valuable training, before prosthesis is implanted, appears as good feedback; besides, these patients can be hired as specialized operators in semi-automatized industry

  5. Two-dimensional myoelectric control of a robotic arm for upper limb amputees

    Science.gov (United States)

    López Celani, Natalia M.; Soria, Carlos M.; Orosco, Eugenio C.; di Sciascio, Fernando A.; Valentinuzzi, Max E.

    2007-11-01

    Rehabilitation engineering and medicine have become integral and significant parts of health care services, particularly and unfortunately in the last three or four decades, because of wars, terrorism and large number of car accidents. Amputees show a high rate of rejection to wear prosthetic devices, often because of lack of an adequate period of adaptation. A robotic arm may appear as a good preliminary stage. To test the hypothesis, myoelectric signals from two upper limb amputees and from four normal volunteers were fed, via adequate electronic conditioning and using MATLAB, to an industrial robotic arm. Proportional strength control was used for two degrees of freedom (x-y plane) by means of eight signal features of control (four traditional statistics plus energy, integral of the absolute value, Willison's amplitude, waveform length and envelope) for comparison purposes, and selecting the best of them as final reference. Patients easily accepted the system and learned in short time how to operate it. Results were encouraging so that valuable training, before prosthesis is implanted, appears as good feedback; besides, these patients can be hired as specialized operators in semi-automatized industry.

  6. Two-dimensional myoelectric control of a robotic arm for upper limb amputees

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Celani, Natalia M [Gabinete de Tecnologia Medica (Argentina); Soria, Carlos M [Instituto de Automatica (INAUT), Universidad Nacional de San Juan (UNSJ), San Juan (Argentina); Orosco, Eugenio C [Gabinete de Tecnologia Medica (Argentina); Di Sciascio, Fernando A [Instituto de Automatica (INAUT), Universidad Nacional de San Juan (UNSJ), San Juan (Argentina); Valentinuzzi, Max E [Gabinete de Tecnologia Medica (Argentina)

    2007-11-15

    Rehabilitation engineering and medicine have become integral and significant parts of health care services, particularly and unfortunately in the last three or four decades, because of wars, terrorism and large number of car accidents. Amputees show a high rate of rejection to wear prosthetic devices, often because of lack of an adequate period of adaptation. A robotic arm may appear as a good preliminary stage. To test the hypothesis, myoelectric signals from two upper limb amputees and from four normal volunteers were fed, via adequate electronic conditioning and using MATLAB, to an industrial robotic arm. Proportional strength control was used for two degrees of freedom (x-y plane) by means of eight signal features of control (four traditional statistics plus energy, integral of the absolute value, Willison's amplitude, waveform length and envelope) for comparison purposes, and selecting the best of them as final reference. Patients easily accepted the system and learned in short time how to operate it. Results were encouraging so that valuable training, before prosthesis is implanted, appears as good feedback; besides, these patients can be hired as specialized operators in semi-automatized industry.

  7. Enhancing the versatility of wireless biopotential acquisition for myoelectric prosthetic control

    Science.gov (United States)

    Bercich, Rebecca A.; Wang, Zhi; Mei, Henry; Hammer, Lauren H.; Seburn, Kevin L.; Hargrove, Levi J.; Irazoqui, Pedro P.

    2016-08-01

    Objective. A significant challenge in rehabilitating upper-limb amputees with sophisticated, electric-powered prostheses is sourcing reliable and independent channels of motor control information sufficient to precisely direct multiple degrees of freedom simultaneously. Approach. In response to the expressed needs of clinicians, we have developed a miniature, batteryless recording device that utilizes emerging integrated circuit technology and optimal impedance matching for magnetic resonantly coupled (MRC) wireless power transfer to improve the performance and versatility of wireless electrode interfaces with muscle. Main results. In this work we describe the fabrication and performance of a fully wireless and batteryless EMG recording system and use of this system to direct virtual and electric-powered limbs in real-time. The advantage of using MRC to optimize power transfer to a network of wireless devices is exhibited by EMG collected from an array of eight devices placed circumferentially around a human subject’s forearm. Significance. This is a comprehensive, low-cost, and non-proprietary solution that provides unprecedented versatility of configuration to direct myoelectric prostheses without wired connections to the body. The amenability of MRC to varied coil geometries and arrangements has the potential to improve the efficiency and robustness of wireless power transfer links at all levels of upper-limb amputation. Additionally, the wireless recording device’s programmable flash memory and selectable features will grant clinicians the unique ability to adapt and personalize the recording system’s functional protocol for patient- or algorithm-specific needs.

  8. Transcranial direct current stimulation versus user training on improving online myoelectric control for amputees

    Science.gov (United States)

    Pan, Lizhi; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Zhu, Xiangyang

    2017-08-01

    Objective. Transcranial direct current stimulation (tDCS) and user training (UT) are two types of methods to improve myoelectric control performance for amputees. In this study, we compared the independent effect between tDCS and UT, and investigated the combined effect of tDCS and UT. Approach. An online paradigm of simultaneous and proportional control (SPC) based on electromyography (EMG) was adopted. The proposed experiments were conducted on six naïve unilateral trans-radial amputees. The subjects each received three types of 20 min interventions: active tDCS with motor training (tDCS  +  UT), active tDCS with quiet sitting (tDCS), and sham tDCS with motor training (UT). The interventions were applied at one week intervals in a randomized order. The subjects performed online control of a feedback arrow with two degrees of freedom (DoFs) to accomplish target reaching motor tasks in pre-sessions and post-sessions. We compared the performance, measured by completion rate, completion time, and efficiency coefficient, between pre-sessions and post-sessions. Main results. The results showed that the intervention tDCS  +  UT and tDCS significantly improved the online SPC performance (i.e. improved the completion rate; reduced the completion time; and improved the efficiency coefficient), while intervention UT did not significantly change the performance. The results also showed that the online SPC performance after intervention tDCS  +  UT and tDCS was not significantly different, but both were significantly better than that after intervention UT. Significance. tDCS could be an effective intervention to improve the online SPC performance in a short time.

  9. Improved prosthetic hand control with concurrent use of myoelectric and inertial measurements

    OpenAIRE

    Krasoulis, Agamemnon; Kyranou, Iris; Erden, Mustapha Suphi; Nazarpour, Kianoush; Vijayakumar, Sethu

    2017-01-01

    Background Myoelectric pattern recognition systems can decode movement intention to drive upper-limb prostheses. Despite recent advances in academic research, the commercial adoption of such systems remains low. This limitation is mainly due to the lack of classification robustness and a simultaneous requirement for a large number of electromyogram (EMG) electrodes. We propose to address these two issues by using a multi-modal approach which combines surface electromyography (sEMG) with inert...

  10. Functional Assessment of a Myoelectric Postural Controller and Multi-Functional Prosthetic Hand by Persons With Trans-Radial Limb Loss.

    Science.gov (United States)

    Segil, Jacob L; Huddle, Stephen A; Weir, Richard F Ff

    2017-06-01

    The functional assessment of myoelectric control algorithms by persons with amputation promotes the overarching goal of the field of prosthetic limb design: to replace what was lost. However, many studies use experimental paradigms with virtual interfaces and able-bodied subjects that do not capture the challenges of a clinical implementation with an amputee population. A myoelectric control system must be robust to variable physiology, loading effects of the prosthesis on the limb, and limb position effects during dynamic tasks. Here persons with transradial limb loss performed activities of daily living using a postural controller and multi-functional prosthetic hand in order to verify that the postural controller was robust to these clinical challenges. The Southampton Hand Assessment Procedure was performed by persons with limb loss and able-bodied subjects. The results indicate that persons with limb loss and able-limbed subjects achieved the same performance and therefore that the clinical challenges were overcome. Persons with limb loss achieved 55% of physiological hand function on average. Also, the postural controller is compared to other state of the art myoelectric controllers and prosthetic hands previously tested. This work confirms that the postural controller is potentially a clinically-viable method to control myoelectric multi-functional prosthetic hands.

  11. Effects of Slackline Training on Postural Control, Jump Performance, and Myoelectrical Activity in Female Basketball Players.

    Science.gov (United States)

    Santos, Luis; Fernández-Río, Javier; Fernández-García, Benjamín; Jakobsen, Markus D; González-Gómez, Lucía; Suman, Oscar E

    2016-03-01

    The main goal of the study was to assess the effects of slackline training on the postural control system and jump performance of athletes. Twenty-five female basketball players were randomized into 2 groups: control (N = 12) and experimental (N = 13). The latter experienced a 6-week supervised slackline training (3 sessions per week, 5-9 minutes per session). Participants underwent center of pressure (CoP) testing through three 10-second tasks (bipedal, left leg, and right leg support) over firm and compliant surfaces with eyes open. Several CoP parameters were assessed: length, area, length/area, speed, Ymean, Xmean, deltaY, deltaX, RMS (root-mean-squared amplitude of the CoP), RMSY, and RMSX. Surface electromyography recordings were obtained too. Participants were also tested on jump performance, provided perceived exertion (6-20 Borg scale) and local muscle perceived exertion. Center of pressure parameters significantly differed before and after training only in the experimental group and only on the compliant surface (left leg: length, area, speed, deltaY, and deltaX; right leg: length, speed, Ymean, deltaY, and RMSY). Surface electromyography recordings were comparable before and after training in both groups. Performance on a countermovement jump test significantly improved only in the experimental group (effect side was 3.21 and 1.36 [flight time and jump height, respectively], which is described as a large effect). Mechanical power of the legs, as measured through the 30-second maximal performance jump test, did not improve in either group. The slackline training was rated as "somewhat hard" with the quadriceps, soleus, and gastrocnemius being rated as the most engaged muscles. Data indicate that slacklining requires activation of the main lower limb muscles. On conclusion, slacklining may be a valid cross-training tool for female basketball players.

  12. Advanced Myoelectric Control for Robotic Hand-Assisted Training: Outcome from a Stroke Patient.

    Science.gov (United States)

    Lu, Zhiyuan; Tong, Kai-Yu; Shin, Henry; Li, Sheng; Zhou, Ping

    2017-01-01

    A hand exoskeleton driven by myoelectric pattern recognition was designed for stroke rehabilitation. It detects and recognizes the user's motion intent based on electromyography (EMG) signals, and then helps the user to accomplish hand motions in real time. The hand exoskeleton can perform six kinds of motions, including the whole hand closing/opening, tripod pinch/opening, and the "gun" sign/opening. A 52-year-old woman, 8 months after stroke, made 20× 2-h visits over 10 weeks to participate in robot-assisted hand training. Though she was unable to move her fingers on her right hand before the training, EMG activities could be detected on her right forearm. In each visit, she took 4× 10-min robot-assisted training sessions, in which she repeated the aforementioned six motion patterns assisted by our intent-driven hand exoskeleton. After the training, her grip force increased from 1.5 to 2.7 kg, her pinch force increased from 1.5 to 2.5 kg, her score of Box and Block test increased from 3 to 7, her score of Fugl-Meyer (Part C) increased from 0 to 7, and her hand function increased from Stage 1 to Stage 2 in Chedoke-McMaster assessment. The results demonstrate the feasibility of robot-assisted training driven by myoelectric pattern recognition after stroke.

  13. First-in-man demonstration of a fully implanted myoelectric sensors system to control an advanced electromechanical prosthetic hand.

    Science.gov (United States)

    Pasquina, Paul F; Evangelista, Melissa; Carvalho, A J; Lockhart, Joseph; Griffin, Sarah; Nanos, George; McKay, Patricia; Hansen, Morten; Ipsen, Derek; Vandersea, James; Butkus, Josef; Miller, Matthew; Murphy, Ian; Hankin, David

    2015-04-15

    Advanced motorized prosthetic devices are currently controlled by EMG signals generated by residual muscles and recorded by surface electrodes on the skin. These surface recordings are often inconsistent and unreliable, leading to high prosthetic abandonment rates for individuals with upper limb amputation. Surface electrodes are limited because of poor skin contact, socket rotation, residual limb sweating, and their ability to only record signals from superficial muscles, whose function frequently does not relate to the intended prosthetic function. More sophisticated prosthetic devices require a stable and reliable interface between the user and robotic hand to improve upper limb prosthetic function. Implantable Myoelectric Sensors (IMES(®)) are small electrodes intended to detect and wirelessly transmit EMG signals to an electromechanical prosthetic hand via an electro-magnetic coil built into the prosthetic socket. This system is designed to simultaneously capture EMG signals from multiple residual limb muscles, allowing the natural control of multiple degrees of freedom simultaneously. We report the status of the first FDA-approved clinical trial of the IMES(®) System. This study is currently in progress, limiting reporting to only preliminary results. Our first subject has reported the ability to accomplish a greater variety and complexity of tasks in his everyday life compared to what could be achieved with his previous myoelectric prosthesis. The interim results of this study indicate the feasibility of utilizing IMES(®) technology to reliably sense and wirelessly transmit EMG signals from residual muscles to intuitively control a three degree-of-freedom prosthetic arm. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. First-in-Man Demonstration of Fully Implanted Myoelectric Sensors for Control of an Advanced Electromechanical Arm by Transradial Amputees

    Science.gov (United States)

    Pasquina, Paul F.; Evangelista, Melissa; Carvalho, Antonio J.; Lockhart, Joseph; Griffin, Sarah; Nanos, George; McKay, Patricia; Hansen, Morten; Ipsen, Derek; Vandersea, James; Butkus, Josef; Miller, Matthew; Murphy, Ian; Hankin, David

    2014-01-01

    Background Advanced motorized prosthetic devices are currently controlled by EMG signals generated by residual muscles and recorded by surface electrodes on the skin. These surface recordings are often inconsistent and unreliable, leading to high prosthetic abandonment rates for individuals with upper limb amputation. Surface electrodes are limited because of poor skin contact, socket rotation, residual limb sweating, and their ability to only record signals from superficial muscles, whose function frequently does not relate to the intended prosthetic function. More sophisticated prosthetic devices require a stable and reliable interface between the user and robotic hand to improve upper limb prosthetic function. New Method Implantable Myoelectric Sensors (IMES®) are small electrodes intended to detect and wirelessly transmit EMG signals to an electromechanical prosthetic hand via an electromagnetic coil built into the prosthetic socket. This system is designed to simultaneously capture EMG signals from multiple residual limb muscles, allowing the natural control of multiple degrees of freedom simultaneously. Results We report the status of the first FDA-approved clinical trial of the IMES® System. This study is currently in progress, limiting reporting to only preliminary results. Comparison with Existing Methods Our first subject has reported the ability to accomplish a greater variety and complexity of tasks in his everyday life compared to what could be achieved with his previous myoelectric prosthesis. Conclusion The interim results of this study indicate the feasibility of utilizing IMES® technology to reliably sense and wirelessly transmit EMG signals from residual muscles to intuitively control a three degree-of-freedom prosthetic arm. PMID:25102286

  15. Reinnervated Split-Muscle Technique for Creating Additional Myoelectric Sites in an Animal Model.

    Science.gov (United States)

    Deslivia, Maria Florencia; Lee, Hyun-Joo; Zulkarnain, Rizki Fajar; Zhu, Bin; Adikrishna, Arnold; Jeon, In-Ho; Kim, Keehoon

    2016-12-01

    This study proposes a novel reinnervated split-muscle operation to create additional myoelectric sites as sources of command signals of myoelectric prostheses for enhanced dexterous hand-to-wrist motions. The aim of this study was to investigate the postprocedure electromyographic properties of the muscles as distinct myoelectric sites in a rat model. The reinnervated split-muscle group (n = 6) had the gastrocnemius muscle separated along its longitudinal axis and nerves transferred to each new muscle (peroneal nerve to lateral muscle head and tibial to medial one); the non-split-muscle group (n = 6) only had nerve transfers with its muscle intact. Functional testing was conducted after 10 weeks. The main parameter is the difference in mean electromyographic amplitude between the new muscles, with greater values indicating better separability. After the reinnervated split-muscle procedure, there is a significant increase of the average ratio between two muscles compared with the control group, from 0.44 (range, 0.02 to 0.86) to 0.77 (range, 0.35 to 0.98) (p = 0.011). In addition, compared with the non-split muscle group, nerve transfer in the split-muscle group is more successful in reaching its intended target muscle. A reinnervated split-muscle procedure could be beneficial for acquiring a more precise and discrete command signal in upper limb amputees, thus enabling the creation of more dexterous prosthetic arm.

  16. Hand movements classification for myoelectric control system using adaptive resonance theory.

    Science.gov (United States)

    Jahani Fariman, H; Ahmad, Siti A; Hamiruce Marhaban, M; Alijan Ghasab, M; Chappell, Paul H

    2016-03-01

    This research proposes an exploratory study of a simple, accurate, and computationally efficient movement classification technique for prosthetic hand application. Surface myoelectric signals were acquired from the four muscles, namely, flexor carpi ulnaris, extensor carpi radialis, biceps brachii, and triceps brachii, of four normal-limb subjects. The signals were segmented, and the features were extracted with a new combined time-domain feature extraction method. Fuzzy C-means clustering method and scatter plot were used to evaluate the performance of the proposed multi-feature versus Hudgins' multi-feature. The movements were classified with a hybrid Adaptive Resonance Theory-based neural network. Comparative results indicate that the proposed hybrid classifier not only has good classification accuracy (89.09%) but also a significantly improved computation time.

  17. User adaptation in long-term, open-loop myoelectric training: implications for EMG pattern recognition in prosthesis control

    Science.gov (United States)

    He, Jiayuan; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Farina, Dario; Zhu, Xiangyang

    2015-08-01

    Objective. Recent studies have reported that the classification performance of electromyographic (EMG) signals degrades over time without proper classification retraining. This problem is relevant for the applications of EMG pattern recognition in the control of active prostheses. Approach. In this study we investigated the changes in EMG classification performance over 11 consecutive days in eight able-bodied subjects and two amputees. Main results. It was observed that, when the classifier was trained on data from one day and tested on data from the following day, the classification error decreased exponentially but plateaued after four days for able-bodied subjects and six to nine days for amputees. The between-day performance became gradually closer to the corresponding within-day performance. Significance. These results indicate that the relative changes in EMG signal features over time become progressively smaller when the number of days during which the subjects perform the pre-defined motions are increased. The performance of the motor tasks is thus more consistent over time, resulting in more repeatable EMG patterns, even if the subjects do not have any external feedback on their performance. The learning curves for both able-bodied subjects and subjects with limb deficiencies could be modeled as an exponential function. These results provide important insights into the user adaptation characteristics during practical long-term myoelectric control applications, with implications for the design of an adaptive pattern recognition system.

  18. An Alternative Myoelectric Pattern Recognition Approach for the Control of Hand Prostheses: A Case Study of Use in Daily Life by a Dysmelia Subject

    Science.gov (United States)

    Ahlberg, Johan; Lendaro, Eva; Hermansson, Liselotte; Håkansson, Bo; Ortiz-Catalan, Max

    2018-01-01

    The functionality of upper limb prostheses can be improved by intuitive control strategies that use bioelectric signals measured at the stump level. One such strategy is the decoding of motor volition via myoelectric pattern recognition (MPR), which has shown promising results in controlled environments and more recently in clinical practice. Moreover, not much has been reported about daily life implementation and real-time accuracy of these decoding algorithms. This paper introduces an alternative approach in which MPR allows intuitive control of four different grips and open/close in a multifunctional prosthetic hand. We conducted a clinical proof-of-concept in activities of daily life by constructing a self-contained, MPR-controlled, transradial prosthetic system provided with a novel user interface meant to log errors during real-time operation. The system was used for five days by a unilateral dysmelia subject whose hand had never developed, and who nevertheless learned to generate patterns of myoelectric activity, reported as intuitive, for multi-functional prosthetic control. The subject was instructed to manually log errors when they occurred via the user interface mounted on the prosthesis. This allowed the collection of information about prosthesis usage and real-time classification accuracy. The assessment of capacity for myoelectric control test was used to compare the proposed approach to the conventional prosthetic control approach, direct control. Regarding the MPR approach, the subject reported a more intuitive control when selecting the different grips, but also a higher uncertainty during proportional continuous movements. This paper represents an alternative to the conventional use of MPR, and this alternative may be particularly suitable for a certain type of amputee patients. Moreover, it represents a further validation of MPR with dysmelia cases. PMID:29637030

  19. Vestibular contribution to balance control in the medial gastrocnemius and soleus.

    Science.gov (United States)

    Dakin, Christopher J; Héroux, Martin E; Luu, Billy L; Inglis, John Timothy; Blouin, Jean-Sébastien

    2016-03-01

    The soleus (Sol) and medial gastrocnemius (mGas) muscles have different patterns of activity during standing balance and may have distinct functional roles. Using surface electromyography we previously observed larger responses to galvanic vestibular stimulation (GVS) in the mGas compared with the Sol muscle. However, it is unclear whether this difference is an artifact that reflects limitations associated with surface electromyography recordings or whether a compensatory balance response to a vestibular error signal activates the mGas to a greater extent than the Sol. In the present study, we compared the effect of GVS on the discharge behavior of 9 Sol and 21 mGas motor units from freely standing subjects. In both Sol and mGas motor units, vestibular stimulation induced biphasic responses in measures of discharge timing [11 ± 5.0 (mGas) and 5.6 ± 3.8 (Sol) counts relative to the sham (mean ± SD)], and frequency [0.86 ± 0.6 Hz (mGas), 0.34 ± 0.2 Hz (Sol) change relative to the sham]. Peak-to-trough response amplitudes were significantly larger in the mGas (62% in the probability-based measure and 160% in the frequency-based measure) compared with the Sol (multiple P vestibular signals have a larger influence on the discharge activity of motor units in the mGas compared with the Sol. More tentatively, these results indicate the mGas plays a greater role in vestibular-driven balance corrections during standing balance. Copyright © 2016 the American Physiological Society.

  20. Effects of slackline training on postural control, jump performance, and myoelectrical activity in female basketball players

    DEFF Research Database (Denmark)

    Santos, Luis; Fernández-Río, Javier; Fernández-García, Benjamín

    2016-01-01

    The main goal of the study was to assess the effects of slackline training on the postural control system and jump performance of athletes. Twenty-five female basketball players were randomized into 2 groups: control (N 12) and experimental (N 13). The latter experienced a 6-week supervised......, slacklining may be a valid cross-training tool for female basketball players....... slackline training (3 sessions per week, 5-9 minutes per session). Participants underwent center of pressure (CoP) testing through three 10-second tasks (bipedal, left leg, and right leg support) over firm and compliant surfaces with eyes open. Several CoP parameters were assessed: length, area, length...

  1. Application of dexterous space robotics technology to myoelectric prostheses

    Science.gov (United States)

    Hess, Clifford; Li, Larry C. H.; Farry, Kristin A.; Walker, Ian D.

    1994-01-01

    Future space missions will require robots equipped with highly dexterous robotic hands to perform a variety of tasks. A major technical challenge in making this possible is an improvement in the way these dexterous robotic hands are remotely controlled or teleoperated. NASA is currently investigating the feasibility of using myoelectric signals to teleoperate a dexterous robotic hand. In theory, myoelectric control of robotic hands will require little or no mechanical parts and will greatly reduce the bulk and weight usually found in dexterous robotic hand control devices. An improvement in myoelectric control of multifinger hands will also benefit prosthetics users. Therefore, as an effort to transfer dexterous space robotics technology to prosthetics applications and to benefit from existing myoelectric technology, NASA is collaborating with the Limbs of Love Foundation, the Institute for Rehabilitation and Research, and Rice University in developing improved myoelectric control multifinger hands and prostheses. In this paper, we will address the objectives and approaches of this collaborative effort and discuss the technical issues associated with myoelectric control of multifinger hands. We will also report our current progress and discuss plans for future work.

  2. Effect of clinical parameters on the control of myoelectric robotic prosthetic hands.

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Castellini, Claudio; Caputo, Barbara; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Müller, Henning

    2016-01-01

    Improving the functionality of prosthetic hands with noninvasive techniques is still a challenge. Surface electromyography (sEMG) currently gives limited control capabilities; however, the application of machine learning to the analysis of sEMG signals is promising and has recently been applied in practice, but many questions still remain. In this study, we recorded the sEMG activity of the forearm of 11 male subjects with transradial amputation who were mentally performing 40 hand and wrist movements. The classification performance and the number of independent movements (defined as the subset of movements that could be distinguished with >90% accuracy) were studied in relationship to clinical parameters related to the amputation. The analysis showed that classification accuracy and the number of independent movements increased significantly with phantom limb sensation intensity, remaining forearm percentage, and temporal distance to the amputation. The classification results suggest the possibility of naturally controlling up to 11 movements of a robotic prosthetic hand with almost no training. Knowledge of the relationship between classification accuracy and clinical parameters adds new information regarding the nature of phantom limb pain as well as other clinical parameters, and it can lay the foundations for future "functional amputation" procedures in surgery.

  3. Reflex response and control of the human soleus and gastrocnemius muscles during walking and running at increasing velocity

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Alkjær, Tine; Raffalt, Peter C

    2012-01-01

    than the soleus H-reflex. In both muscles the H-reflex increased significantly from walking to running but also with increasing running speed. The peak of EMG activity increased in both muscles with increasing speed. The V-wave of both muscles was absent or rather low during walking, but it increased...... significantly from walking to running with increasing running speed in the soleus but not in the medial gastrocnemius. In both muscles the V-wave was highest just prior to heel strike. It is suggested that this was due to a high firing frequency of the motoneurones in this phase of the movement. It is concluded...

  4. Microarray analysis for delineating the gene expression in biopsies of gastrocnemius muscle of patients with chronic critical limb ischaemia compared with non-ischaemic controls.

    Science.gov (United States)

    Freund, Daniel; Brilloff, Silke; Ghazy, Tamer; Kirschner, Stephan; Gäbel, Gabor; Hinterseher, Irene; Weiss, Norbert; Mahlmann, Adrian

    2018-03-20

    Microarray analysis has been carried out in this pilot study to compare delineated gene expression profiles in the biopsies of skeletal muscle taken from patients with chronic critical limb ischaemia (CLI) and non-ischaemic control subjects. Biopsy of gastrocnemius muscle was obtained from six patients with unreconstructed CLI referred for surgical major amputation. As control, biopsies of six patients undergoing elective knee arthroplasty without evidence of peripheral arterial occlusive disease were taken. The differences in gene expression associated with angiogenic processes in specimens obtained from ischaemic and non-ischaemic skeletal muscle were confirmed by quantitative real-time polymerase chain reaction (PCR) analysis. Compared with non-ischaemic skeletal muscle biopsy of chronic-ischaemic skeletal muscle contained 55 significantly up-regulated and 45 down-regulated genes, out of which 64 genes had a known genetic product ((Author, please revise sentence)). Tissue samples of ischaemic muscle were characterized by increased expression of cell survival factors (e. g. tissue factor pathway inhibitor 2) in combination with reduced expression of cell proliferation effectors (e. g. microfibrillar-associated protein 5 and transferrin receptor). The expression of growth factors (e. g. early growth response 3 and chemokine receptor chemokine C-X-C motif ligand 4) which play a central role in arterial and angiogenic processes and anti-angiogenetic factors (e. g. pentraxin 3) were increased in chronic ischaemic skeletal muscle. An increased expression of extracellular matrix proteins (e. g. cysteine-rich angiogenic inducer 61) was also observed. Gene expression profiles in biopsies of gastrocnemius muscle in patients with chronic critical limb ischaemia showed an increase in pro-survival factors, extracellular matrix protein deposition, and impaired proliferation, compared with non-ischaemic controls. Further studies are required to analyse the endogenous repair

  5. Intermanual Transfer Effects in Below-Elbow Myoelectric Prosthesis Users.

    Science.gov (United States)

    de Boer, Errit; Romkema, Sietske; Cutti, Andrea G; Brouwers, Michael A; Bongers, Raoul M; van der Sluis, Corry K

    2016-11-01

    To determine intermanual transfer effects in patients with a below-elbow amputation using a myoelectric prosthesis and to establish whether laterality affects these effects. Case-control. A standardized setting in a rehabilitation clinic. A convenience sample (N=44) of experienced myoelectric prosthesis users (n=22) and matched controls (n=22). Controls were matched on sex, age (±5y), and hand dominance. Both the experienced group and the control group performed several tasks using a prosthesis simulator attached to their nonaffected arm. Movement time, force control, Box and Block test (BBT) scores, and duration of hand opening. Movement times of myoelectric prosthesis users were shorter, and these users had significantly higher BBT scores and shorter hand opening durations than those of controls. No intermanual transfer effects on force control and no laterality effects were found. Intermanual transfer effects were present in experienced myoelectric prosthesis users with a below-elbow amputation, independent of laterality. These findings support the clinical relevance of intermanual transfer training, which may facilitate persons with an upper limb amputation to start training directly after the amputation. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  6. Intermanual transfer effects in below-elbow myoelectric prosthesis users

    NARCIS (Netherlands)

    de Boer, Errit; Romkema, Sietske; Cutti, Andrea G; Brouwers, Michael A H; Bongers, Raoul M; van der Sluis, Corry K

    2016-01-01

    OBJECTIVE: To determine intermanual transfer effects in patients with a below-elbow amputation using a myoelectric prosthesis, and to establish whether laterality affects these effects. DESIGN: Case-control. SETTING: A standardized setting in a rehabilitation clinic. PARTICIPANTS: A convenience

  7. Classification complexity in myoelectric pattern recognition.

    Science.gov (United States)

    Nilsson, Niclas; Håkansson, Bo; Ortiz-Catalan, Max

    2017-07-10

    Limb prosthetics, exoskeletons, and neurorehabilitation devices can be intuitively controlled using myoelectric pattern recognition (MPR) to decode the subject's intended movement. In conventional MPR, descriptive electromyography (EMG) features representing the intended movement are fed into a classification algorithm. The separability of the different movements in the feature space significantly affects the classification complexity. Classification complexity estimating algorithms (CCEAs) were studied in this work in order to improve feature selection, predict MPR performance, and inform on faulty data acquisition. CCEAs such as nearest neighbor separability (NNS), purity, repeatability index (RI), and separability index (SI) were evaluated based on their correlation with classification accuracy, as well as on their suitability to produce highly performing EMG feature sets. SI was evaluated using Mahalanobis distance, Bhattacharyya distance, Hellinger distance, Kullback-Leibler divergence, and a modified version of Mahalanobis distance. Three commonly used classifiers in MPR were used to compute classification accuracy (linear discriminant analysis (LDA), multi-layer perceptron (MLP), and support vector machine (SVM)). The algorithms and analytic graphical user interfaces produced in this work are freely available in BioPatRec. NNS and SI were found to be highly correlated with classification accuracy (correlations up to 0.98 for both algorithms) and capable of yielding highly descriptive feature sets. Additionally, the experiments revealed how the level of correlation between the inputs of the classifiers influences classification accuracy, and emphasizes the classifiers' sensitivity to such redundancy. This study deepens the understanding of the classification complexity in prediction of motor volition based on myoelectric information. It also provides researchers with tools to analyze myoelectric recordings in order to improve classification performance.

  8. Myoelectric stimulation on peroneal muscles resists simulated ankle sprain motion.

    Science.gov (United States)

    Fong, Daniel Tik-Pui; Chu, Vikki Wing-Shan; Chan, Kai-Ming

    2012-07-26

    The inadequate reaction time of the peroneal muscles in response to an incorrect foot contact event has been proposed as one of the etiological factors contributing to ankle joint inversion injury. Thus, the current study aimed to investigate the efficacy of a myoelectric stimulation applied to the peroneal muscles in the prevention of a simulated ankle inversion trauma. Ten healthy male subjects performed simulated inversion and supination tests on a pair of mechanical sprain simulators. An electrical signal was delivered to the peroneal muscles of the subjects through a pair of electrode pads. The start of the stimulus was synchronized with the drop of the sprain simulator's platform. In order to determine the maximum delay time which the stimulus could still resist the simulated ankle sprain motion, different delay time were test (0, 5, 10, and 15ms). Together with the control trial (no stimulus), there were 5 testing conditions for both simulated inversion and supination test. The effect was quantified by the drop in maximum ankle tilting angle and angular velocity, as determined by a motion analysis system with a standard laboratory procedure. Results showed that the myoelectric stimulation was effective in all conditions except the one with myoelectric stimulus delayed for 15ms in simulated supination test. It is concluded that myoelectric stimulation on peroneal muscles could resist an ankle spraining motion. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Arm rehabilitation in post stroke subjects: A randomized controlled trial on the efficacy of myoelectrically driven FES applied in a task-oriented approach.

    Science.gov (United States)

    Jonsdottir, Johanna; Thorsen, Rune; Aprile, Irene; Galeri, Silvia; Spannocchi, Giovanna; Beghi, Ettore; Bianchi, Elisa; Montesano, Angelo; Ferrarin, Maurizio

    2017-01-01

    Motor recovery of persons after stroke may be enhanced by a novel approach where residual muscle activity is facilitated by patient-controlled electrical muscle activation. Myoelectric activity from hemiparetic muscles is then used for continuous control of functional electrical stimulation (MeCFES) of same or synergic muscles to promote restoration of movements during task-oriented therapy (TOT). Use of MeCFES during TOT may help to obtain a larger functional and neurological recovery than otherwise possible. Multicenter randomized controlled trial. Eighty two acute and chronic stroke victims were recruited through the collaborating facilities and after signing an informed consent were randomized to receive either the experimental (MeCFES assisted TOT (M-TOT) or conventional rehabilitation care including TOT (C-TOT). Both groups received 45 minutes of rehabilitation over 25 sessions. Outcomes were Action Research Arm Test (ARAT), Upper Extremity Fugl-Meyer Assessment (FMA-UE) scores and Disability of the Arm Shoulder and Hand questionnaire. Sixty eight subjects completed the protocol (Mean age 66.2, range 36.5-88.7, onset months 12.7, range 0.8-19.1) of which 45 were seen at follow up 5 weeks later. There were significant improvements in both groups on ARAT (median improvement: MeCFES TOT group 3.0; C-TOT group 2.0) and FMA-UE (median improvement: M-TOT 4.5; C-TOT 3.5). Considering subacute subjects (time since stroke rehabilitation (57.9%) than in the C-TOT group (33.2%) (difference in proportion improved 24.7%; 95% CI -4.0; 48.6), though the study did not meet the planned sample size. This is the first large multicentre RCT to compare MeCFES assisted TOT with conventional care TOT for the upper extremity. No adverse events or negative outcomes were encountered, thus we conclude that MeCFES can be a safe adjunct to rehabilitation that could promote recovery of upper limb function in persons after stroke, particularly when applied in the subacute phase.

  10. An experimental evaluation of the incidence of fitness-function/search-algorithm combinations on the classification performance of myoelectric control systems with iPCA tuning

    Science.gov (United States)

    2013-01-01

    Background The information of electromyographic signals can be used by Myoelectric Control Systems (MCSs) to actuate prostheses. These devices allow the performing of movements that cannot be carried out by persons with amputated limbs. The state of the art in the development of MCSs is based on the use of individual principal component analysis (iPCA) as a stage of pre-processing of the classifiers. The iPCA pre-processing implies an optimization stage which has not yet been deeply explored. Methods The present study considers two factors in the iPCA stage: namely A (the fitness function), and B (the search algorithm). The A factor comprises two levels, namely A1 (the classification error) and A2 (the correlation factor). Otherwise, the B factor has four levels, specifically B1 (the Sequential Forward Selection, SFS), B2 (the Sequential Floating Forward Selection, SFFS), B3 (Artificial Bee Colony, ABC), and B4 (Particle Swarm Optimization, PSO). This work evaluates the incidence of each one of the eight possible combinations between A and B factors over the classification error of the MCS. Results A two factor ANOVA was performed on the computed classification errors and determined that: (1) the interactive effects over the classification error are not significative (F0.01,3,72 = 4.0659 > f AB  = 0.09), (2) the levels of factor A have significative effects on the classification error (F0.02,1,72 = 5.0162  f B  = 0.08). Conclusions Considering the classification performance we found a superiority of using the factor A2 in combination with any of the levels of factor B. With respect to the time performance the analysis suggests that the PSO algorithm is at least 14 percent better than its best competitor. The latter behavior has been observed for a particular configuration set of parameters in the search algorithms. Future works will investigate the effect of these parameters in the classification performance, such as length of the reduced

  11. Association of gastrocnemius tendon calcification with chondrocalcinosis of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Foldes, K. [Department of Radiology, Veterans Administration Medical Center (VAMC), San Diego, CA (United States)]|[University of California San Diego Medical Center (UCSD), San Diego, CA (United States)]|[National Institute of Rheumatology and Physiotherapy, Budapest (Hungary); Lenchik, L. [Department of Radiology, Veterans Administration Medical Center (VAMC), San Diego, CA (United States)]|[University of California San Diego Medical Center (UCSD), San Diego, CA (United States); Jaovisidha, S. [Department of Radiology, Veterans Administration Medical Center (VAMC), San Diego, CA (United States)]|[University of California San Diego Medical Center (UCSD), San Diego, CA (United States); Clopton, P. [Department of Radiology, Veterans Administration Medical Center (VAMC), San Diego, CA (United States); Sartoris, D.J. [Department of Radiology, Veterans Administration Medical Center (VAMC), San Diego, CA (United States)]|[University of California San Diego Medical Center (UCSD), San Diego, CA (United States); Resnick, D. [Department of Radiology, Veterans Administration Medical Center (VAMC), San Diego, CA (United States)]|[University of California San Diego Medical Center (UCSD), San Diego, CA (United States)

    1996-10-01

    Objective. Chondrocalcinosis of the knee is a common radiological finding in the elderly. However, visualization of chondrocalcinosis may be difficult in patients with advanced cartilage loss.The purpose of this study was to determine sensitivity, specificity, and accuracy of gastrocnemius tendon calcification that might serve as a radiographic marker of chondrocalcinosis in patients with painful knees. Design and patients. We prospectively evaluated 37 knee radiographs in 30 consecutive patients (29 men, 8 women; mean age 67 years, age range 37-90 years) with painful knees who had radiographic evidence of chondrocalcinosis. The frequency of fibrocartilage, hyaline cartilage, and gastrocnemius tendon calcification was determined. For a control group, we evaluated knee radiographs in 65 consecutive patients with knee pain (54 men, 11 women; mean age 59 years, age range 40-93 years) who had no radiological signs of chondrocalcinosis. The frequency of gastrocnemius tendon calcification in the control group was determined. Results. Gastrocnemius tendon calcification was 41% sensitive, 100% specific, and 78% accurate in predicting chondrocalcinosis. The gastrocnemius tendon was calcified on 15 of 37 (41%) radiographs in the experimental group and on 0 of 67 radiographs in the control group. In the chondrocalcinosis group, 23 (62%) had posterior hyaline cartilage calcification, 14 (38%) had anterior hyaline cartilage calcification, 31 (84%) had medial meniscus calcification, and 36 (97%) had lateral meniscus calcification. Conclusions. Our results show that gastrocnemius tendon calcification is an accurate radiographic marker of chondrocalcinosis in patients with knee pain. (orig.). With 2 figs., 2 tabs.

  12. The clinical relevance of advanced artificial feedback in the control of a multi-functional myoelectric prosthesis.

    Science.gov (United States)

    Markovic, Marko; Schweisfurth, Meike A; Engels, Leonard F; Bentz, Tashina; Wüstefeld, Daniela; Farina, Dario; Dosen, Strahinja

    2018-03-27

    To effectively replace the human hand, a prosthesis should seamlessly respond to user intentions but also convey sensory information back to the user. Restoration of sensory feedback is rated highly by the prosthesis users, and feedback is critical for grasping in able-bodied subjects. Nonetheless, the benefits of feedback in prosthetics are still debated. The lack of consensus is likely due to the complex nature of sensory feedback during prosthesis control, so that its effectiveness depends on multiple factors (e.g., task complexity, user learning). We evaluated the impact of these factors with a longitudinal assessment in six amputee subjects, using a clinical setup (socket, embedded control) and a range of tasks (box and blocks, block turn, clothespin and cups relocation). To provide feedback, we have proposed a novel vibrotactile stimulation scheme capable of transmitting multiple variables from a multifunction prosthesis. The subjects wore a bracelet with four by two uniformly placed vibro-tactors providing information on contact, prosthesis state (active function), and grasping force. The subjects also completed a questionnaire for the subjective evaluation of the feedback. The tests demonstrated that feedback was beneficial only in the complex tasks (block turn, clothespin and cups relocation), and that the training had an important, task-dependent impact. In the clothespin relocation and block turn tasks, training allowed the subjects to establish successful feedforward control, and therefore, the feedback became redundant. In the cups relocation task, however, the subjects needed some training to learn how to properly exploit the feedback. The subjective evaluation of the feedback was consistently positive, regardless of the objective benefits. These results underline the multifaceted nature of closed-loop prosthesis control as, depending on the context, the same feedback interface can have different impact on performance. Finally, even if the closed

  13. The clinical relevance of advanced artificial feedback in the control of a multi-functional myoelectric prosthesis

    DEFF Research Database (Denmark)

    Markovic, Marko; Schweisfurth, Meike A.; Engels, Leonard F.

    2018-01-01

    BACKGROUND: To effectively replace the human hand, a prosthesis should seamlessly respond to user intentions but also convey sensory information back to the user. Restoration of sensory feedback is rated highly by the prosthesis users, and feedback is critical for grasping in able-bodied subjects....... Nonetheless, the benefits of feedback in prosthetics are still debated. The lack of consensus is likely due to the complex nature of sensory feedback during prosthesis control, so that its effectiveness depends on multiple factors (e.g., task complexity, user learning). METHODS: We evaluated the impact...... multiple variables from a multifunction prosthesis. The subjects wore a bracelet with four by two uniformly placed vibro-tactors providing information on contact, prosthesis state (active function), and grasping force. The subjects also completed a questionnaire for the subjective evaluation...

  14. A 3-DOF hemi-constrained wrist motion/force detection device for deploying simultaneous myoelectric control.

    Science.gov (United States)

    Yang, Wei; Yang, Dapeng; Liu, Yu; Liu, Hong

    2018-03-05

    For describing the state of the wrist, either the force or movement of wrist can be measured as the training target in the simultaneous electromyography control. However, the relationship between the force and movement is so complex that only the force or movement is not precise enough to describe its actual situations. In this paper, we propose a novel platform that can acquire three degrees of freedom (DOF) wrist motion/force synchronously with multi-channel electromyography signals in a hemi-constraint way. The self-made wrist force-movement mapping device establishes a stable relationship between the wrist movement and force. Meanwhile, the elicited wrist movement can be directly fed back to the subjects via laser cursor. The information of the cursor can directly reflect the 3-DOF movement of the wrist without any decoupling algorithms. Through this platform, the support vector regression model learned from the training data can well predict the arbitrary combinations of 3-DOF wrist movements. The cross-validation result indicates that the regression accuracy of free 3-DOF movements can reach a similar performance to that of 2-DOF regular movements (in terms of R 2 , regular movement vs. free movement, p > 0.1). Graphical abstract The hemi-constrained platform used for detecting 3-DOF wrist movements.

  15. Locomotor adaptation to a powered ankle-foot orthosis depends on control method

    Directory of Open Access Journals (Sweden)

    Gordon Keith E

    2007-12-01

    Full Text Available Abstract Background We studied human locomotor adaptation to powered ankle-foot orthoses with the intent of identifying differences between two different orthosis control methods. The first orthosis control method used a footswitch to provide bang-bang control (a kinematic control and the second orthosis control method used a proportional myoelectric signal from the soleus (a physiological control. Both controllers activated an artificial pneumatic muscle providing plantar flexion torque. Methods Subjects walked on a treadmill for two thirty-minute sessions spaced three days apart under either footswitch control (n = 6 or myoelectric control (n = 6. We recorded lower limb electromyography (EMG, joint kinematics, and orthosis kinetics. We compared stance phase EMG amplitudes, correlation of joint angle patterns, and mechanical work performed by the powered orthosis between the two controllers over time. Results During steady state at the end of the second session, subjects using proportional myoelectric control had much lower soleus and gastrocnemius activation than the subjects using footswitch control. The substantial decrease in triceps surae recruitment allowed the proportional myoelectric control subjects to walk with ankle kinematics close to normal and reduce negative work performed by the orthosis. The footswitch control subjects walked with substantially perturbed ankle kinematics and performed more negative work with the orthosis. Conclusion These results provide evidence that the choice of orthosis control method can greatly alter how humans adapt to powered orthosis assistance during walking. Specifically, proportional myoelectric control results in larger reductions in muscle activation and gait kinematics more similar to normal compared to footswitch control.

  16. Isolated gastrocnemius recession for achilles tendinopathy: strength and functional outcomes.

    Science.gov (United States)

    Nawoczenski, Deborah A; Barske, Heather; Tome, Joshua; Dawson, Laura K; Zlotnicki, Jason P; DiGiovanni, Benedict F

    2015-01-21

    Gastrocnemius recession has emerged as a viable intervention for patients with recalcitrant foot and ankle disorders associated with isolated gastrocnemius contracture. The purpose of this case-control study was to investigate the effects of an isolated gastrocnemius recession on pain, patient-reported function, and strength in patients with chronic Achilles tendinopathy and an isolated gastrocnemius contracture. Thirteen patients with unilateral Achilles tendinopathy (mean age [and standard deviation], fifty-two ± 7.7 years) who received a gastrocnemius recession and ten matched-control subjects participated. A visual analog scale was used to assess pain, and the Foot and Ankle Ability Measure was used to evaluate patient-reported function in activities of daily living and sports. Patients were asked about their satisfaction with the results of the gastrocnemius recession. Ankle plantar flexion peak torque was assessed at 60°/sec and 120°/sec. Appropriate t tests were used to assess limb symmetry and strength differences between the groups. The mean duration of follow-up was eighteen months (range, twelve to twenty-eight months). Gastrocnemius recession provided significant pain relief (mean preoperative visual analog scale score [and standard deviation], 6.8 ± 1.8; mean follow-up visual analog scale score, 1.4 ± 2.7; p recession provides significant and sustained pain relief for chronic Achilles tendinopathy. Good function can be expected for activities of daily living, but power and endurance activities were more problematic for the Achilles tendinopathy group. Isokinetic strength assessment may not effectively capture patient-reported functional deficits. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  17. Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient.

    Science.gov (United States)

    Ortiz-Catalan, Max; Sander, Nichlas; Kristoffersen, Morten B; Håkansson, Bo; Brånemark, Rickard

    2014-01-01

    A variety of treatments have been historically used to alleviate phantom limb pain (PLP) with varying efficacy. Recently, virtual reality (VR) has been employed as a more sophisticated mirror therapy. Despite the advantages of VR over a conventional mirror, this approach has retained the use of the contralateral limb and is therefore restricted to unilateral amputees. Moreover, this strategy disregards the actual effort made by the patient to produce phantom motions. In this work, we investigate a treatment in which the virtual limb responds directly to myoelectric activity at the stump, while the illusion of a restored limb is enhanced through augmented reality (AR). Further, phantom motions are facilitated and encouraged through gaming. The proposed set of technologies was administered to a chronic PLP patient who has shown resistance to a variety of treatments (including mirror therapy) for 48 years. Individual and simultaneous phantom movements were predicted using myoelectric pattern recognition and were then used as input for VR and AR environments, as well as for a racing game. The sustained level of pain reported by the patient was gradually reduced to complete pain-free periods. The phantom posture initially reported as a strongly closed fist was gradually relaxed, interestingly resembling the neutral posture displayed by the virtual limb. The patient acquired the ability to freely move his phantom limb, and a telescopic effect was observed where the position of the phantom hand was restored to the anatomically correct distance. More importantly, the effect of the interventions was positively and noticeably perceived by the patient and his relatives. Despite the limitation of a single case study, the successful results of the proposed system in a patient for whom other medical and non-medical treatments have been ineffective justifies and motivates further investigation in a wider study.

  18. Treatment of phantom limb pain (PLP based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient

    Directory of Open Access Journals (Sweden)

    Max eOrtiz-Catalan

    2014-02-01

    Full Text Available A variety of treatments have been historically used to alleviate phantom limb pain (PLP with varying efficacy. Recently, virtual reality (VR has been employed as a more sophisticated mirror therapy. Despite the advantages of VR over a conventional mirror, this approach has retained the use of the contralateral limb and is therefore restricted to unilateral amputees. Moreover, this strategy disregards the actual effort made by the patient to produce phantom motions. In this work, we investigate a treatment in which the virtual limb responds directly to myoelectric activity at the stump, while the illusion of a restored limb is enhanced through augmented reality (AR. Further, phantom motions are facilitated and encouraged through gaming.The proposed set of technologies was administered to a chronic PLP patient who has shown resistance to a variety of treatments (including mirror therapy for 48 years. Individual and simultaneous phantom movements were predicted using myoelectric pattern recognition and were then used as input for VR and AR environments, as well as for a racing game.The sustained level of pain reported by the patient was gradually reduced to complete pain-free periods. The phantom posture initially reported as a strongly closed fist was gradually relaxed, interestingly resembling the neutral posture displayed by the virtual limb. The patient acquired the ability to freely move his phantom limb and a telescopic effect was observed where the position of the phantom hand was restored to the anatomically correct distance. More importantly, the effect of the interventions was positively and noticeably perceived by the patient and his relatives.Despite the limitation of a single case study, the successful results of the proposed system in a patient for whom other medical and non-medical treatments have been ineffective justifies and motivates further investigation in a wider study.

  19. Cardinality as a Highly Descriptive Feature in Myoelectric Pattern Recognition for Decoding Motor Volition

    Directory of Open Access Journals (Sweden)

    Max eOrtiz-Catalan

    2015-10-01

    Full Text Available Accurate descriptors of muscular activity play an important role in clinical practice and rehabilitation research. Such descriptors are features of myoelectric signals extracted from sliding time windows. A wide variety of myoelectric features have been used as inputs to pattern recognition algorithms that aim to decode motor volition. The output of these algorithms can then be used to control limb prostheses, exoskeletons, and rehabilitation therapies. In the present study, cardinality is introduced and compared with traditional time-domain (Hudgins’ set and other recently proposed myoelectric features (for example, rough entropy. Cardinality was found to consistently outperform other features, including those that are more sophisticated and computationally expensive, despite variations in sampling frequency, time window length, contraction dynamics, type and number of movements (single or simultaneous, and classification algorithms. Provided that the signal resolution is kept between 12 and 14 bits, cardinality improves myoelectric pattern recognition for the prediction of motion volition. This technology is instrumental for the rehabilitation of amputees and patients with motor impairments where myoelectric signals are viable. All code and data used in this work is available online within BioPatRec.

  20. Cardinality as a highly descriptive feature in myoelectric pattern recognition for decoding motor volition.

    Science.gov (United States)

    Ortiz-Catalan, Max

    2015-01-01

    Accurate descriptors of muscular activity play an important role in clinical practice and rehabilitation research. Such descriptors are features of myoelectric signals extracted from sliding time windows. A wide variety of myoelectric features have been used as inputs to pattern recognition algorithms that aim to decode motor volition. The output of these algorithms can then be used to control limb prostheses, exoskeletons, and rehabilitation therapies. In the present study, cardinality is introduced and compared with traditional time-domain (Hudgins' set) and other recently proposed myoelectric features (for example, rough entropy). Cardinality was found to consistently outperform other features, including those that are more sophisticated and computationally expensive, despite variations in sampling frequency, time window length, contraction dynamics, type, and number of movements (single or simultaneous), and classification algorithms. Provided that the signal resolution is kept between 12 and 14 bits, cardinality improves myoelectric pattern recognition for the prediction of motion volition. This technology is instrumental for the rehabilitation of amputees and patients with motor impairments where myoelectric signals are viable. All code and data used in this work is available online within BioPatRec.

  1. Electromyographyc evaluation of movements of lower limb in double pulley system equipment: comparison between gastrocnemius (caput laterale) and gluteus maximus.

    Science.gov (United States)

    Tassi, N; Engrácia Valenti, V

    2007-09-01

    It was evaluated movements of lower limb in the double pulley system equipment on ten male volunteers during contraction of gastrocnemius (caput laterale) and gluteus maximus muscles in the following movements: 1) hip extension with extended knee and erect trunk, 2) hip extension with flexed knee and erect trunk, 3) hip extension with flexed knee and erect trunk, 3) hip extension with extended knee and inclined trunk, 5) hip abduction along the midline, 7) hip abduction with extension beyond the midline, 8) adduction with hip flexion beyond the midline, 8) adduction with hip flexion beyond the midline, and 9) adduction with hip extension beyond the midline. Myoelectric signals were taken up by Lec Tec surface electrodes connected to a 6-channel Lynx electromyographic signal amplifier coupled with a computer equipped with a model CAD 10/26 analogue digital conversion board and with a specific software for signal recording and analysis. We observed weak gastrocnemius muscle activity for all movements studied. In the case of gluteus maximus, the most important potentials were observed for movement 2, while for the remaining movements the actions were of reasonable intensity. Compared to gluteus, gastrocnemius was less required for all movements.

  2. Research, design and development project Myoelectric Prosthesis of Upper Limb

    International Nuclear Information System (INIS)

    Galiano, L; Montaner, E; Flecha, A

    2007-01-01

    A Research Design and Development Project was developed of a myoelectric prosthesis for a pediatric patient presenting congenital amputation of the left forearm below the elbow. A multidisciplinary work-team was formed for this goal, in order to solve the several (/various) aspects regarding this project (mechanical, ergonomics, electronics, physical). The prosthesis as an electromechanical device was divided in several blocks, trying to achieve a focused development for each stage, acording to requisites. A mechanical prototype of the prothesis was designed and built along with the circuitry needed for EMG aquisition, control logic and drivers. Having acomplished the previuos stages, the project is now dealing with the definitions of the interface between the prosthesis and the patient, with promising perspectives

  3. Research, design and development project Myoelectric Prosthesis of Upper Limb

    Energy Technology Data Exchange (ETDEWEB)

    Galiano, L; Montaner, E; Flecha, A [Bioparx, J Hernandez 1101, Parana, ERios (Argentina)

    2007-11-15

    A Research Design and Development Project was developed of a myoelectric prosthesis for a pediatric patient presenting congenital amputation of the left forearm below the elbow. A multidisciplinary work-team was formed for this goal, in order to solve the several (/various) aspects regarding this project (mechanical, ergonomics, electronics, physical). The prosthesis as an electromechanical device was divided in several blocks, trying to achieve a focused development for each stage, acording to requisites. A mechanical prototype of the prothesis was designed and built along with the circuitry needed for EMG aquisition, control logic and drivers. Having acomplished the previuos stages, the project is now dealing with the definitions of the interface between the prosthesis and the patient, with promising perspectives.

  4. Altered Biomechanical Properties of Gastrocnemius Tendons of Turkeys Infected with Turkey Arthritis Reovirus

    Directory of Open Access Journals (Sweden)

    Tamer A. Sharafeldin

    2016-01-01

    Full Text Available Turkey arthritis reovirus (TARV causes lameness and tenosynovitis in commercial turkeys and is often associated with gastrocnemius tendon rupture by the marketing age. This study was undertaken to characterize the biomechanical properties of tendons from reovirus-infected turkeys. One-week-old turkey poults were orally inoculated with O’Neil strain of TARV and observed for up to 16 weeks of age. Lameness was first observed at 8 weeks of age, which continued at 12 and 16 weeks. At 4, 8, 12, and 16 weeks of age, samples were collected from legs. Left intertarsal joint with adjacent gastrocnemius tendon was collected and processed for histological examination. The right gastrocnemius tendon’s tensile strength and elasticity modulus were analyzed by stressing each tendon to the point of rupture. At 16 weeks of age, gastrocnemius tendons of TARV-infected turkeys showed significantly reduced (P<0.05 tensile strength and modulus of elasticity as compared to those of noninfected control turkeys. Gastrocnemius tendons revealed lymphocytic tendinitis/tenosynovitis beginning at 4 weeks of age, continuing through 8 and 12 weeks, and progressing to fibrosis from 12 to 16 weeks of age. We propose that tendon fibrosis is one of the key features contributing to reduction in tensile strength and elasticity of gastrocnemius tendons in TARV-infected turkeys.

  5. Development of prosthesis grasp control systems on a robotic testbed

    NARCIS (Netherlands)

    Peerdeman, B.; Fabrizi, Ugo; Palli, Gianluca; Melchiorri, Claudio; Stramigioli, Stefano; Misra, Sarthak

    2012-01-01

    Modern myoelectric hand prostheses continue to increase in functionality, while their control is constrained by the limits of myoelectric input. This paper covers the development and testing of grasp control systems for multifunctional myoelectric prosthetic hands. The functionality of modern hand

  6. Variability of the morphology of gastrocnemius muscle in an African ...

    African Journals Online (AJOL)

    ... palpation of popliteal arterial pulse, popliteal nerve block and the assessment of gastrocnemius muscle for autografting. The additional variant heads also bear evolutionary importance. Keywords: Gastrocnemius; Multi-Pinnate; Popliteal Entrapment Syndrome; Variations; Four-Headed, Third Head Of Gastrocnemius ...

  7. Does botulinum toxin injection site determine outcome in post-stroke plantarflexion spasticity? Comparison study of two injection sites in the gastrocnemius muscle: a randomized double-blind controlled trial.

    Science.gov (United States)

    Im, Sun; Park, Joo Hyun; Son, Seong Kon; Shin, Jae-Eun; Cho, Sae Hoon; Park, Geun-Young

    2014-06-01

    To determine if botulinum toxin type A injection at the proximal 2/10 and 3/10 of calf length, where the intramuscular nerve endings of the gastrocnemius muscle are densely distributed, is more efficacious in controlling plantarflexion spasticity than injection at distant sites within the same muscle. A double-blind randomized controlled trial. Two rehabilitation centres. Forty stroke patients were randomly allocated to two groups. Group A received injection at the proximal 2/10 and 3/10 of calf length, group B at and below the midbelly of the muscle. Both groups received 200 IU of botulinum toxin A and were followed up to eight weeks. Primary variables were the surface electromyography values recorded during plantarflexion; secondary variables were the Modified Ashworth Scale, Modified Tardieu Scale, clonus scale, 10-metre walking test, ABILOCO and Functional Ambulation Categories. At baseline, the median Modified Ashworth Scale was 2.0 (range,1+ -3.0), and there were no significant differences between the two groups in all the parameters, including spasticity. Compared to baseline, no significant differences between the two groups were detected in all the surface electromyography and clinical parameters at week 8 (P > 0.05). Both groups showed significant improvement of spasticity with a median Modified Ashworth Scale of 1+ (range, 0.0-2.0) at eight weeks. Botulinum toxin A injection was associated with a significant improvement from baseline to week 8 in both treatment groups, however, no significant difference between the 2 groups was observed, based on the electrophysiological and clinical parameters employed in this study. © The Author(s) 2014.

  8. Visceral perceptions and gastric myoelectrical activity in healthy women and in patients with bulimia nervosa.

    Science.gov (United States)

    Koch, K L; Bingaman, S; Tan, L; Stern, R M

    1998-02-01

    Bulimia nervosa remains a common eating disorder in young women. Little is known about upper gastrointestinal symptoms or gastric motility in patients with bulimia nervosa. The aim of this study was to measure gastric myoelectrical activity and hunger/satiety and stomach emptiness/fullness before and after a non-nutrient water load and solid-phase gastric emptying in hospitalized patients with bulimia nervosa (n = 12) and in healthy women (n = 13). Gastric myoelectrical activity was measured by means of cutaneous electrodes; visual analogue scales were used to measure perceptions of hunger/satiety and stomach emptiness/fullness. Before and after a standard water load the bulimia patients reported significantly greater stomach fullness and satiety compared with control subjects (P scrambled eggs showed the lag phase was shortened in the bulimic patients (16 +/- 4 min vs 31 +/- 4 min in controls, P < 0.01), but the percentage of meal emptied at 2 h was similar to control values. bulimia patients had exaggerated perceptions of stomach fullness and satiety in response to water; and abnormal gastric myoelectrical activity and accelerated lag phase of gastric emptying were objective stomach abnormalities detected in hospitalized patients with bulimia nervosa.

  9. EMG feature assessment for myoelectric pattern recognition and channel selection: a study with incomplete spinal cord injury.

    Science.gov (United States)

    Liu, Jie; Li, Xiaoyan; Li, Guanglin; Zhou, Ping

    2014-07-01

    Myoelectric pattern recognition with a large number of electromyogram (EMG) channels provides an approach to assessing motor control information available from the recorded muscles. In order to develop a practical myoelectric control system, a feature dependent channel reduction method was developed in this study to determine a small number of EMG channels for myoelectric pattern recognition analysis. The method selects appropriate raw EMG features for classification of different movements, using the minimum Redundancy Maximum Relevance (mRMR) and the Markov random field (MRF) methods to rank a large number of EMG features, respectively. A k-nearest neighbor (KNN) classifier was used to evaluate the performance of the selected features in terms of classification accuracy. The method was tested using 57 channels' surface EMG signals recorded from forearm and hand muscles of individuals with incomplete spinal cord injury (SCI). Our results demonstrate that appropriate selection of a small number of raw EMG features from different recording channels resulted in similar high classification accuracies as achieved by using all the EMG channels or features. Compared with the conventional sequential forward selection (SFS) method, the feature dependent method does not require repeated classifier implementation. It can effectively reduce redundant information not only cross different channels, but also cross different features in the same channel. Such hybrid feature-channel selection from a large number of EMG recording channels can reduce computational cost for implementation of a myoelectric pattern recognition based control system. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  10. Myoelectric manifestations of jaw elevator muscle fatigue and recovery in healthy and TMD subjects.

    Science.gov (United States)

    Castroflorio, T; Falla, D; Tartaglia, G M; Sforza, C; Deregibus, A

    2012-09-01

    The effects of muscle pain and fatigue on the control of jaw elevator muscles are not well known. Furthermore, the myoelectric manifestations of fatigue and recovery from fatigue in the masticatory muscles are not reported in literature. The main aims of this study were (i) to evaluate the possible use of surface electromyography (sEMG) as an objective measure of fatigue of the jaw elevator muscles, (ii) to compare the myoelectric manifestations of fatigue in the temporalis anterior and masseter muscles bilaterally, (iii) to assess recovery of the investigated muscles after an endurance test and (iv) to compare fatigue and recovery of the jaw elevator muscles in healthy subjects and patients with muscle-related temporomandibular disorders (TMD). The study was performed on twenty healthy volunteers and eighteen patients with muscle-related TMD. An intra-oral compressive-force sensor was used to measure the voluntary contraction forces close to the intercuspal position and to provide visual feedback of submaximal forces to the subject. Surface EMG signals were recorded with linear electrode arrays during isometric contractions at 20%, 40%, 60% and 80% of the maximum voluntary contraction force, during an endurance test and during the recovery phase. The results showed that (i) the slope of the mean power spectral frequency (MNF) and the initial average rectified value (ARV) could be used to monitor fatigue of the jaw elevators, (ii) the temporalis anterior and masseter muscle show the same myoelectric manifestations of fatigue and recovery and (iii) the initial values of MNF and ARV were lower in patients with muscle-related TMD. The assessment of myoelectric manifestations of fatigue in the masticatory muscles may assist in the clinical assessment of TMDs. © 2012 Blackwell Publishing Ltd.

  11. Passive mechanical properties of gastrocnemius muscles of people with ankle contracture after stroke.

    Science.gov (United States)

    Kwah, Li Khim; Herbert, Robert D; Harvey, Lisa A; Diong, Joanna; Clarke, Jillian L; Martin, Joshua H; Clarke, Elizabeth C; Hoang, Phu D; Bilston, Lynne E; Gandevia, Simon C

    2012-07-01

    To investigate the mechanisms of contracture after stroke by comparing passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in people with ankle contracture after stroke with control participants. Cross-sectional study. Laboratory in a research institution. A convenience sample of people with ankle contracture after stroke (n=20) and able-bodied control subjects (n=30). Not applicable. Stiffness and lengths of gastrocnemius muscle-tendon units, lengths of muscle fascicles, and tendons at specific tensions. At a tension of 100N, the gastrocnemius muscle-tendon unit was significantly shorter in participants with stroke (mean, 436mm) than in able-bodied control participants (mean, 444mm; difference, 8mm; 95% confidence interval [CI], 0.2-15mm; P=.04). Muscle fascicles were also shorter in the stroke group (mean, 44mm) than in the control group (mean, 50mm; difference, 6mm; 95% CI, 1-12mm; P=.03). There were no significant differences between groups in the mean stiffness or length of the muscle-tendon units and fascicles at low tension, or in the mean length of the tendons at any tension. People with ankle contracture after stroke have shorter gastrocnemius muscle-tendon units and muscle fascicles than control participants at high tension. This difference is not apparent at low tension. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  12. Morphological Alterations in Gastrocnemius and Soleus Muscles in Male and Female Mice in a Fibromyalgia Model.

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    Gabriel Alejandro Bonaterra

    Full Text Available Fibromyalgia (FM is a chronic musculoskeletal pain disorder, characterized by chronic widespread pain and bodily tenderness and is often accompanied by affective disturbances, however often with unknown etiology. According to recent reports, physical and psychological stress trigger FM. To develop new treatments for FM, experimental animal models for FM are needed to be development and characterized. Using a mouse model for FM including intermittent cold stress (ICS, we hypothesized that ICS leads to morphological alterations in skeletal muscles in mice.Male and female ICS mice were kept under alternating temperature (4 °C/room temperature [22 °C]; mice constantly kept at room temperature served as control. After scarification, gastrocnemius and soleus muscles were removed and snap-frozen in liquid nitrogen-cooled isopentane or fixed for electron microscopy.In gastrocnemius/soleus muscles of male ICS mice, we found a 21.6% and 33.2% decrease of fiber cross sectional area (FCSA, which in soleus muscle concerns the loss of type IIa and IIx FCSA. This phenomenon was not seen in muscles of female ICS mice. However, this loss in male ICS mice was associated with an increase in gastrocnemius of the density of MIF+ (8.6%-, MuRF+ (14.7%-, Fbxo32+ (17.8%-cells, a 12.1% loss of capillary contacts/muscle fiber as well as a 30.7% increase of damaged mitochondria in comparison with male control mice. Moreover, significant positive correlations exist among densities (n/mm(2 of MIF+, MuRF+, Fbxo32+-cells in gastrocnemius/ soleus muscles of male ICS mice; these cell densities inversely correlate with FCSA especially in gastrocnemius muscle of male ICS mice.The ICS-induced decrease of FCSA mainly concerns gastrocnemius muscle of male mice due to an increase of inflammatory and atrogenic cells. In soleus muscle of male ICS and soleus/gastrocnemius muscles of female ICS mice morphological alterations seem to occur not at all or delayed. The sex-specificity of

  13. Myoelectrical Manifestation of Fatigue Less Prominent in Patients with Cancer Related Fatigue

    Science.gov (United States)

    Kisiel-Sajewicz, Katarzyna; Siemionow, Vlodek; Seyidova-Khoshknabi, Dilara; Davis, Mellar P.; Wyant, Alexandria; Ranganathan, Vinoth K.; Walsh, Declan; Yan, Jin H.; Hou, Juliet; Yue, Guang H.

    2013-01-01

    Purpose A lack of fatigue-related muscle contractile property changes at time of perceived physical exhaustion and greater central than peripheral fatigue detected by twitch interpolation technique have recently been reported in cancer survivors with fatigue symptoms. Based on these observations, it was hypothesized that compared to healthy people, myoelectrical manifestation of fatigue in the performing muscles would be less significant in these individuals while sustaining a prolonged motor task to self-perceived exhaustion (SPE) since their central fatigue was more prominent. The purpose of this study was to test this hypothesis by examining electromyographic (EMG) signal changes during fatiguing muscle performance. Methods Twelve individuals who had advanced solid cancer and cancer-related fatigue (CRF), and 12 age- and gender-matched healthy controls performed a sustained elbow flexion at 30% maximal voluntary contraction till SPE. Amplitude and mean power frequency (MPF) of EMG signals of the biceps brachii, brachioradialis, and triceps brachii muscles were evaluated when the individuals experienced minimal, moderate, and severe fatigue. Results CRF patients perceived physical “exhaustion” significantly sooner than the controls. The myoelectrical manifestation of muscular fatigue assessed by EMG amplitude and MPF was less significant in CRF than controls. The lower MPF even at minimal fatigue stage in CRF may indicate pathophysiologic condition of the muscle. Conclusions CRF patients experience less myoelectrical manifestation of muscle fatigue than healthy individuals near the time of SPE. The data suggest that central nervous system fatigue plays a more important role in limiting endurance-type of motor performance in patients with CRF. PMID:24391800

  14. A pneumatically powered knee-ankle-foot orthosis (KAFO) with myoelectric activation and inhibition

    Science.gov (United States)

    Sawicki, Gregory S; Ferris, Daniel P

    2009-01-01

    Background The goal of this study was to test the mechanical performance of a prototype knee-ankle-foot orthosis (KAFO) powered by artificial pneumatic muscles during human walking. We had previously built a powered ankle-foot orthosis (AFO) and used it effectively in studies on human motor adaptation, locomotion energetics, and gait rehabilitation. Extending the previous AFO to a KAFO presented additional challenges related to the force-length properties of the artificial pneumatic muscles and the presence of multiple antagonistic artificial pneumatic muscle pairs. Methods Three healthy males were fitted with custom KAFOs equipped with artificial pneumatic muscles to power ankle plantar flexion/dorsiflexion and knee extension/flexion. Subjects walked over ground at 1.25 m/s under four conditions without extensive practice: 1) without wearing the orthosis, 2) wearing the orthosis with artificial muscles turned off, 3) wearing the orthosis activated under direct proportional myoelectric control, and 4) wearing the orthosis activated under proportional myoelectric control with flexor inhibition produced by leg extensor muscle activation. We collected joint kinematics, ground reaction forces, electromyography, and orthosis kinetics. Results The KAFO produced ~22%–33% of the peak knee flexor moment, ~15%–33% of the peak extensor moment, ~42%–46% of the peak plantar flexor moment, and ~83%–129% of the peak dorsiflexor moment during normal walking. With flexor inhibition produced by leg extensor muscle activation, ankle (Pearson r-value = 0.74 ± 0.04) and knee ( r = 0.95 ± 0.04) joint kinematic profiles were more similar to the without orthosis condition compared to when there was no flexor inhibition (r = 0.49 ± 0.13 for ankle, p = 0.05, and r = 0.90 ± 0.03 for knee, p = 0.17). Conclusion The proportional myoelectric control with flexor inhibition allowed for a more normal gait than direct proportional myoelectric control. The current orthosis design

  15. A pneumatically powered knee-ankle-foot orthosis (KAFO with myoelectric activation and inhibition

    Directory of Open Access Journals (Sweden)

    Ferris Daniel P

    2009-06-01

    Full Text Available Abstract Background The goal of this study was to test the mechanical performance of a prototype knee-ankle-foot orthosis (KAFO powered by artificial pneumatic muscles during human walking. We had previously built a powered ankle-foot orthosis (AFO and used it effectively in studies on human motor adaptation, locomotion energetics, and gait rehabilitation. Extending the previous AFO to a KAFO presented additional challenges related to the force-length properties of the artificial pneumatic muscles and the presence of multiple antagonistic artificial pneumatic muscle pairs. Methods Three healthy males were fitted with custom KAFOs equipped with artificial pneumatic muscles to power ankle plantar flexion/dorsiflexion and knee extension/flexion. Subjects walked over ground at 1.25 m/s under four conditions without extensive practice: 1 without wearing the orthosis, 2 wearing the orthosis with artificial muscles turned off, 3 wearing the orthosis activated under direct proportional myoelectric control, and 4 wearing the orthosis activated under proportional myoelectric control with flexor inhibition produced by leg extensor muscle activation. We collected joint kinematics, ground reaction forces, electromyography, and orthosis kinetics. Results The KAFO produced ~22%–33% of the peak knee flexor moment, ~15%–33% of the peak extensor moment, ~42%–46% of the peak plantar flexor moment, and ~83%–129% of the peak dorsiflexor moment during normal walking. With flexor inhibition produced by leg extensor muscle activation, ankle (Pearson r-value = 0.74 ± 0.04 and knee ( r = 0.95 ± 0.04 joint kinematic profiles were more similar to the without orthosis condition compared to when there was no flexor inhibition (r = 0.49 ± 0.13 for ankle, p = 0.05, and r = 0.90 ± 0.03 for knee, p = 0.17. Conclusion The proportional myoelectric control with flexor inhibition allowed for a more normal gait than direct proportional myoelectric control. The current

  16. Wavelet Packet Feature Assessment for High-Density Myoelectric Pattern Recognition and Channel Selection toward Stroke Rehabilitation.

    Science.gov (United States)

    Wang, Dongqing; Zhang, Xu; Gao, Xiaoping; Chen, Xiang; Zhou, Ping

    2016-01-01

    This study presents wavelet packet feature assessment of neural control information in paretic upper limb muscles of stroke survivors for myoelectric pattern recognition, taking advantage of high-resolution time-frequency representations of surface electromyogram (EMG) signals. On this basis, a novel channel selection method was developed by combining the Fisher's class separability index and the sequential feedforward selection analyses, in order to determine a small number of appropriate EMG channels from original high-density EMG electrode array. The advantages of the wavelet packet features and the channel selection analyses were further illustrated by comparing with previous conventional approaches, in terms of classification performance when identifying 20 functional arm/hand movements implemented by 12 stroke survivors. This study offers a practical approach including paretic EMG feature extraction and channel selection that enables active myoelectric control of multiple degrees of freedom with paretic muscles. All these efforts will facilitate upper limb dexterity restoration and improved stroke rehabilitation.

  17. Gastrocnemius operating length with ankle foot orthoses in cerebral palsy.

    Science.gov (United States)

    Choi, Hwan; Wren, Tishya Anne Leong; Steele, Katherine Muterspaugh

    2017-06-01

    Many individuals with cerebral palsy wear ankle foot orthoses during daily life. Orthoses influence joint motion, but how they impact muscle remains unclear. In particular, the gastrocnemius is commonly stiff in cerebral palsy. Understanding whether orthoses stretch or shorten this muscle during daily life may inform orthosis design and rehabilitation. This study investigated the impact of different ankle foot orthoses on gastrocnemius operating length during walking in children with cerebral palsy. Case series, within subject comparison of gastrocnemius operating length while walking barefoot and with two types of ankle foot orthoses. We performed gait analyses for 11 children with cerebral palsy. Each child was fit with two types of orthoses: a dynamic ankle foot orthosis (Cascade dynamic ankle foot orthosis) and an adjustable dynamic response ankle foot orthosis (Ultraflex ankle foot orthosis). Musculoskeletal modeling was used to quantify gastrocnemius musculotendon operating length and velocity with each orthosis. Walking with ankle foot orthoses could stretch the gastrocnemius more than barefoot walking for some individuals; however, there was significant variability between participants and orthoses. At least one type of orthosis stretched the gastrocnemius during walking for 4/6 and 3/5 of the Gross Motor Functional Classification System Level I and III participants, respectively. AFOs also reduced peak gastrocnemius lengthening velocity compared to barefoot walking for some participants, with greater reductions among the Gross Motor Functional Classification System Level III participants. Changes in gastrocnemius operating length and lengthening velocity were related to changes in ankle and knee kinematics during gait. Ankle foot orthoses impact gastrocnemius operating length during walking and, with proper design, may assist with stretching tight muscles in daily life. Clinical relevance Determining whether ankle foot orthoses stretch tight muscles can

  18. Battery powered neuromuscular stimulator circuit for use during simultaneous recording of myoelectric signals.

    Science.gov (United States)

    Thorsen, Rune; Ferrarin, Maurizio

    2009-10-01

    Surface Functional Electrical Stimulation (FES) requires high stimulation voltages. A step-up transformer in the output stage of the stimulation circuit is often used. In the present technical paper a voltage controlled current source (VCCS) is presented as an alternative to the transformer coupling. Two (master-slave) coupled transconductance amplifiers (TAs)--in series with pre-charged capacitors--are used to drive the output current. After each stimulation pulse the capacitors are recharged to a high voltage by a switch mode power supply (SMPS). A multiplexer in the output stage is used to provide biphasic output. Output rise-time (10-90%) was less than 2 micros at 100 mA output. Biphasic charge balanced stimulation current can be produced with a net current to ground of less than 20 nA, thus virtually separated from ground. The circuit permits recording of the volitional myoelectric signal from the stimulated muscle. It is part of a portable myoelectrically controlled FES system powered by 2 AA batteries and currently used in clinical trials.

  19. Feature dimensionality reduction for myoelectric pattern recognition: a comparison study of feature selection and feature projection methods.

    Science.gov (United States)

    Liu, Jie

    2014-12-01

    This study investigates the effect of the feature dimensionality reduction strategies on the classification of surface electromyography (EMG) signals toward developing a practical myoelectric control system. Two dimensionality reduction strategies, feature selection and feature projection, were tested on both EMG feature sets, respectively. A feature selection based myoelectric pattern recognition system was introduced to select the features by eliminating the redundant features of EMG recordings instead of directly choosing a subset of EMG channels. The Markov random field (MRF) method and a forward orthogonal search algorithm were employed to evaluate the contribution of each individual feature to the classification, respectively. Our results from 15 healthy subjects indicate that, with a feature selection analysis, independent of the type of feature set, across all subjects high overall accuracies can be achieved in classification of seven different forearm motions with a small number of top ranked original EMG features obtained from the forearm muscles (average overall classification accuracy >95% with 12 selected EMG features). Compared to various feature dimensionality reduction techniques in myoelectric pattern recognition, the proposed filter-based feature selection approach is independent of the type of classification algorithms and features, which can effectively reduce the redundant information not only across different channels, but also cross different features in the same channel. This may enable robust EMG feature dimensionality reduction without needing to change ongoing, practical use of classification algorithms, an important step toward clinical utility. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Surface EMG and muscle fatigue: multi-channel approaches to the study of myoelectric manifestations of muscle fatigue.

    Science.gov (United States)

    Marco, Gazzoni; Alberto, Botter; Taian, Vieira

    2017-05-01

    In a broad view, fatigue is used to indicate a degree of weariness. On a muscular level, fatigue posits the reduced capacity of muscle fibres to produce force, even in the presence of motor neuron excitation via either spinal mechanisms or electric pulses applied externally. Prior to decreased force, when sustaining physically demanding tasks, alterations in the muscle electrical properties take place. These alterations, termed myoelectric manifestation of fatigue, can be assessed non-invasively with a pair of surface electrodes positioned appropriately on the target muscle; traditional approach. A relatively more recent approach consists of the use of multiple electrodes. This multi-channel approach provides access to a set of physiologically relevant variables on the global muscle level or on the level of single motor units, opening new fronts for the study of muscle fatigue; it allows for: (i) a more precise quantification of the propagation velocity, a physiological variable of marked interest to the study of fatigue; (ii) the assessment of regional, myoelectric manifestations of fatigue; (iii) the analysis of single motor units, with the possibility to obtain information about motor unit control and fibre membrane changes. This review provides a methodological account on the multi-channel approach for the study of myoelectric manifestation of fatigue and on the experimental conditions to which it applies, as well as examples of their current applications.

  1. Selection of suitable hand gestures for reliable myoelectric human computer interface.

    Science.gov (United States)

    Castro, Maria Claudia F; Arjunan, Sridhar P; Kumar, Dinesh K

    2015-04-09

    Myoelectric controlled prosthetic hand requires machine based identification of hand gestures using surface electromyogram (sEMG) recorded from the forearm muscles. This study has observed that a sub-set of the hand gestures have to be selected for an accurate automated hand gesture recognition, and reports a method to select these gestures to maximize the sensitivity and specificity. Experiments were conducted where sEMG was recorded from the muscles of the forearm while subjects performed hand gestures and then was classified off-line. The performances of ten gestures were ranked using the proposed Positive-Negative Performance Measurement Index (PNM), generated by a series of confusion matrices. When using all the ten gestures, the sensitivity and specificity was 80.0% and 97.8%. After ranking the gestures using the PNM, six gestures were selected and these gave sensitivity and specificity greater than 95% (96.5% and 99.3%); Hand open, Hand close, Little finger flexion, Ring finger flexion, Middle finger flexion and Thumb flexion. This work has shown that reliable myoelectric based human computer interface systems require careful selection of the gestures that have to be recognized and without such selection, the reliability is poor.

  2. Kinesio taping and the circulation and endurance ratio of the gastrocnemius muscle.

    Science.gov (United States)

    Stedge, Hannah L; Kroskie, Ryan M; Docherty, Carrie L

    2012-01-01

    Kinesio Tex tape is a therapeutic tape that is applied with the Kinesio-taping (KT) method and is theorized to increase circulation and subsequently improve muscle function. However, little research has been conducted to determine how KT affects performance. To determine the effect of KT on muscular endurance ratio, blood flow, circumference, and volume of the gastrocnemius muscle. Randomized controlled clinical trial. Research laboratory. Patients or Other Participants: Sixty-one healthy, active people (23 men, 38 women; age = 19.99 ± 8.01 years, height = 169.42 ± 23.62 cm, mass = 71.53 ± 36.77 kg) volunteered to participate. They were assigned randomly to 1 of 3 groups: treatment KT, sham KT, and control. Tape was applied based on group assignment. The treatment KT group received the ankle-tape technique as described in the KT manual. The sham KT group received 1 strip of Kinesio Tex tape around the circumference of the proximal gastrocnemius muscle. The control group did not receive tape application. The dependent variables were blood flow in blood perfusion units, volume of water displacement in milliliters, circumference of the gastrocnemius muscle in centimeters, and endurance ratio in joules measured before, 24 hours after, and 72 hours after the intervention. Separate repeated-measures analyses of variance were conducted for each dependent variable. We found no group-by-test day interaction for endurance ratios (F(4,116) = 1.99, P = .10). Blood flow, circumference, and volume measurements also yielded no differences among groups (F(2,58) range, 0.02-0.51; P > .05) or test days (F(2,116) range, 0.05-2.33; P > .05). We found KT does not enhance anaerobic muscle function measured by endurance ratio. The KT also did not affect circulation or volume of the gastrocnemius muscle in a healthy population.

  3. Plasma platelet-rich autogenous healing tendon of the gastrocnemius muscle in rabbits

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    Duvaldo Eurides

    2015-04-01

    Full Text Available Tendon lesions may involve the partial or total section of the common calcaneal tendon and cause postural changes of the member. This study evaluated, after 45 and 90 postoperative days (PO, the repair of the tendon of gastrocnemius muscle of rabbits with topical application of autologous platelet concentrate. Twelve adult rabbits were divided into two groups (n = 6 undergoing cardiac puncture and collection of 10 ml of blood to obtain platelet rich-plasma (PRP. Animals of both groups had a transverse tenotomy in the middle third of the lateral belly of the gastrocnemius tendon and muscle that was approximated with modified Kessler suture and nylon thread. In the animals of the treated group it was applied the average of 490.644 platelets / uL of PRP, per animal over the tendon synthesis. The treated group showed a higher amount of collagen fibers than the control one, and at 90 PO days the intensity of collagen was higher than at 45 days with more fibroblasts in the control than in treated one. The administration of plasma autogenous platelet concentrate in the repair of the gastrocnemius tendon of rabbits stimulates and organizes the repair process and causes early production of collagen fibers.

  4. Effects of the physiological parameters on the signal-to-noise ratio of single myoelectric channel

    Directory of Open Access Journals (Sweden)

    Zhang YT

    2007-08-01

    Full Text Available Abstract Background An important measure of the performance of a myoelectric (ME control system for powered artificial limbs is the signal-to-noise ratio (SNR at the output of ME channel. However, few studies illustrated the neuron-muscular interactive effects on the SNR at ME control channel output. In order to obtain a comprehensive understanding on the relationship between the physiology of individual motor unit and the ME control performance, this study investigates the effects of physiological factors on the SNR of single ME channel by an analytical and simulation approach, where the SNR is defined as the ratio of the mean squared value estimation at the channel output and the variance of the estimation. Methods Mathematical models are formulated based on three fundamental elements: a motoneuron firing mechanism, motor unit action potential (MUAP module, and signal processor. Myoelectric signals of a motor unit are synthesized with different physiological parameters, and the corresponding SNR of single ME channel is numerically calculated. Effects of physiological multi factors on the SNR are investigated, including properties of the motoneuron, MUAP waveform, recruitment order, and firing pattern, etc. Results The results of the mathematical model, supported by simulation, indicate that the SNR of a single ME channel is associated with the voluntary contraction level. We showed that a model-based approach can provide insight into the key factors and bioprocess in ME control. The results of this modelling work can be potentially used in the improvement of ME control performance and for the training of amputees with powered prostheses. Conclusion The SNR of single ME channel is a force, neuronal and muscular property dependent parameter. The theoretical model provides possible guidance to enhance the SNR of ME channel by controlling physiological variables or conscious contraction level.

  5. Denervation of rabbit gastrocnemius and soleus muscles: effect on muscle-specific enolase.

    Science.gov (United States)

    Nozais, M; Merkulova, T; Keller, A; Janmot, C; Lompré, A M; D'Albis, A; Lucas, M

    1999-07-01

    We report here, for the first time, the expression of the muscle-specific isoform of the glycolytic enzyme, enolase (EC 4.2.1. 11) (beta enolase), in rabbit skeletal muscles. We have analysed the fast-twitch gastrocnemius and the slow-twitch soleus muscles during normal postnatal development and following denervation. We show that, in rabbit, as already described in rodents, beta enolase gene expression behaves as a good marker of the fast-twitch fibers. In soleus muscle, the beta enolase transcript level is 10-20% of that found in gastrocnemius. Denervation, performed at 8 postnatal days, induces an important drop of beta enolase transcript levels in both developing soleus and gastrocnemius muscles, with a 80% decrease observed 1 week after denervation in the operated muscles, as compared to the corresponding contralateral muscles. Thereafter, the beta enolase transcript level continues to decrease in the fast-twitch muscle, with the beta enolase subunit being detectable only in the atrophic fast-twitch fibers. In contrast, the beta transcript level tends to increase in the denervated slow-twitch muscle, reaching about 50% of that in contralateral soleus, at 7 weeks after surgery. The level of beta enolase transcripts still expressed after denervation seems to stabilize at the same low level in both types of inactive muscles. This suggests that the small fraction of beta enolase expression which is not controlled by the nerve, or by the contractile activity imposed by it, is independent of the muscle phenotype.

  6. The role of the biarticular hamstrings and gastrocnemius muscles in closed chain lower limb extension.

    Science.gov (United States)

    Cleather, Daniel J; Southgate, Dominic F L; Bull, Anthony M J

    2015-01-21

    The role of the biarticular muscles is a topic that has received considerable attention however their function is not well understood. In this paper, we argue that an analysis that is based upon considering the effect of the biarticular muscles on the segments that they span (rather than their effect on joint rotations) can be illuminating. We demonstrate that this understanding is predicated on a consideration of the relative sizes of the moment arms of a biarticular muscle about the two joints that it crosses. The weight of the previous literature suggests that the moment arms of both the biarticular hamstrings and gastrocnemius are smaller at the knee than at the hip or ankle, (respectively). This in turn leads to the conclusion that both biarticular hamstrings and gastrocnemius are extensors of the lower limb. We show that the existence of these biarticular structures lends a degree of flexibility to the motor control strategies available for lower limb extension. In particular, the role of the gastrocnemius and biarticular hamstrings in permitting a large involvement of the quadriceps musculature in closed chain lower limb extension may be more important than is typically portrayed. Finally, the analysis presented in this paper demonstrates the importance of considering the effects of muscles on the body as a whole, not just on the joints they span. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Changes in geometry of actively shortening unipennate rat gastrocnemius muscle

    NARCIS (Netherlands)

    Zuurbier, C. J.; Huijing, P. A.

    1993-01-01

    Muscle geometry of the unipennate medial gastrocnemius (GM) muscle of the rat was examined with photographic techniques during isometric contractions at different muscle lengths. It was found that the length of fibers in different regions of GM differs significantly, and proximal aponeurosis length

  8. ULTRASONOGRAPHIC EVALUATION OF THE RUPTURED MEDIAL HEAD OF GASTROCNEMIUS MUSCLE

    Directory of Open Access Journals (Sweden)

    Damir Lukac

    Full Text Available ABSTRACT Introduction: Tennis leg, a common injury of the medial head of gastrocnemius muscle in the muscle-tendon junction, is usually reported in men during recreational sports. Sudden pain is the main symptom accompanied by the feeling of rupture in the calf. Clinical examination followed by ultrasound is the standard diagnostic procedure. Objective: The main objectives of this study are to compare clinical and ultrasonographic findings in cases of tennis leg, evaluate the location and type of lesion in the medial head of gastrocnemius muscle, and evaluate the edema volume and the presence of deep vein thrombosis (DVT. Second, the healing process was monitored with ultrasound to distinguish the level of recovery and to record the presence of chronic sequelae. Methods: Eighty-one subjects with clinical symptoms of rupture of the medial head of gastrocnemius muscle participated in the study. A linear probe (7-12 MHz was used for ultrasonographic (US and a Doppler was used to verify the presence of DVT. Results: In 78 of 81 subjects examined, we found obvious US changes (96.3% and three of them had no positive findings. In 67 of them, we diagnosed rupture of the medial head of the gastrocnemius muscle. Most of them had partial rupture (73.13% and the remaining had total rupture (26.87%. The edema (30.84% was found in the space between the aponeurosis of the gastrocnemius and soleus muscles. DVT with the clinical signs of tennis leg was observed in 5 of 81 patients (6.17%. Conclusion: Our findings indicate that ultrasound is very important for early diagnosis of muscle-tendon injuries in the leg. In addition, monitoring the healing process and assessing the chosen treatment showed a high efficiency. Ultrasonography is an effective method to identify and differentiate the sequelae of the injured muscles and vascular complications.

  9. Improving the Robustness of Real-Time Myoelectric Pattern Recognition against Arm Position Changes in Transradial Amputees

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    Yanjuan Geng

    2017-01-01

    Full Text Available Previous studies have showed that arm position variations would significantly degrade the classification performance of myoelectric pattern-recognition-based prosthetic control, and the cascade classifier (CC and multiposition classifier (MPC have been proposed to minimize such degradation in offline scenarios. However, it remains unknown whether these proposed approaches could also perform well in the clinical use of a multifunctional prosthesis control. In this study, the online effect of arm position variation on motion identification was evaluated by using a motion-test environment (MTE developed to mimic the real-time control of myoelectric prostheses. The performance of different classifier configurations in reducing the impact of arm position variation was investigated using four real-time metrics based on dataset obtained from transradial amputees. The results of this study showed that, compared to the commonly used motion classification method, the CC and MPC configurations improved the real-time performance across seven classes of movements in five different arm positions (8.7% and 12.7% increments of motion completion rate, resp.. The results also indicated that high offline classification accuracy might not ensure good real-time performance under variable arm positions, which necessitated the investigation of the real-time control performance to gain proper insight on the clinical implementation of EMG-pattern-recognition-based controllers for limb amputees.

  10. Gastrocnemius muscle contracture after spinal cord injury: a longitudinal study.

    Science.gov (United States)

    Diong, Joanna; Harvey, Lisa A; Kwah, Li Khim; Clarke, Jillian L; Bilston, Lynne E; Gandevia, Simon C; Herbert, Robert D

    2013-07-01

    The aim of this study was to examine changes in passive length and stiffness of the gastrocnemius muscle-tendon unit in people after spinal cord injury. In a prospective longitudinal study, eight wheelchair-dependent participants with severe paralysis were assessed 3 and 12 mos after spinal cord injury. Passive torque-angle data were obtained as the ankle was slowly rotated through range at six knee angles. Differences in passive ankle torque-angle data recorded at different knee angles were used to derive passive length-tension curves of the gastrocnemius muscle-tendon unit. Ultrasound imaging was used to determine fascicle and tendon contributions to the muscle-tendon unit length-tension curves. The participants had ankle contractures (mean [SD] maximum passive ankle dorsiflexion angle, 88 [9] degrees) 3 mos after spinal cord injury. Ankle range did not worsen significantly during the subsequent 9 mos (mean change, -5 degrees; 95% confidence interval, -16 to 6 degrees). There were no changes in the mean slack length or the stiffness of the gastrocnemius muscle-tendon unit or in the slack lengths of the fascicles or the tendon between 3 and 12 mos after spinal cord injury. There were no consistent patterns of the change in slack length or stiffness with the changes in ankle range in the data from the individual participants. This study, the first longitudinal study of muscle length and stiffness after spinal cord injury, showed that the length and the stiffness of the gastrocnemius did not change substantially between 3 and 12 mos after injury.

  11. Gastric myoelectrical activity and gastrointestinal motility in patients with functional dyspepsia

    NARCIS (Netherlands)

    Jebbink, H. J.; van Berge-Henegouwen, G. P.; Bruijs, P. P.; Akkermans, L. M.; Smout, A. J.

    1995-01-01

    The aim of our study was to examine the prevalence of gastric myoelectrical disturbances in relation to gastrointestinal motility abnormalities in patients with functional dyspepsia, using simultaneous electrogastrography and antroduodenojejunal manometry. We carried out electrogastrography in 20

  12. A Quality Function Deployment (QFD approach to designing a prosthetic myoelectric hand

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    Erika Sofía Olaya Escobar

    2005-05-01

    Full Text Available This paper presents a Quality Function Deployment (QFD model based on computing with words. It is specifically used in the House of Quality (HOQ construction phase. It illustrates the methodology employed in designing a prosthetic myoelectric hand.

  13. Upper Limb-Hand 3D Display System for Biomimetic Myoelectric Hand Simulator

    National Research Council Canada - National Science Library

    Jimenez, Gonzalo

    2001-01-01

    A graphics system displaying both upper limb posture and opening-closing of a prosthetic hand was developed for realtime operation of our biomimetic myoelectric hand simulator, Posture of the upper...

  14. Wireless Myoelectric Sensor Minimization and Packaging

    OpenAIRE

    Einarsdóttir, Ásbjörg; Irazoqui, Pedro, Dr.

    2013-01-01

    Many people suffer from amputation, which affects their lives severely by disabling them from doing chores in their daily life as well as chores related to work and leisure. For the last years, prosthetics’ development has been fast and the devices that are being used now are a miracle compared to what has been used before. But still, the battle is not over yet. Although scientists have techniques and devices to use nerve residues from the amputated limb to control the prosthetic, smaller dev...

  15. Reduced biceps femoris myoelectrical activity influences eccentric knee flexor weakness after repeat sprint running.

    Science.gov (United States)

    Timmins, R G; Opar, D A; Williams, M D; Schache, A G; Dear, N M; Shield, A J

    2014-08-01

    The aim of this study was to determine whether declines in knee flexor strength following overground repeat sprints were related to changes in hamstrings myoelectrical activity. Seventeen recreationally active men completed maximal isokinetic concentric and eccentric knee flexor strength assessments at 180°/s before and after repeat sprint running. Myoelectrical activity of the biceps femoris (BF) and medial hamstrings (MHs) was measured during all isokinetic contractions. Repeated measures mixed model [fixed factors = time (pre- and post-repeat sprint) and leg (dominant and nondominant), random factor = participants] design was fitted with the restricted maximal likelihood method. Repeat sprint running resulted in significant declines in eccentric, and concentric, knee flexor strength (eccentric = 26 ± 4 Nm, 15% P Eccentric BF myoelectrical activity was significantly reduced (10%; P = 0.035). Concentric BF and all MH myoelectrical activity were not altered. The declines in maximal eccentric torque were associated with the change in eccentric BF myoelectrical activity (P = 0.013). Following repeat sprint running, there were preferential declines in the myoelectrical activity of the BF, which explained declines in eccentric knee flexor strength. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Effect of a 5-week static stretching program on hardness of the gastrocnemius muscle.

    Science.gov (United States)

    Akagi, R; Takahashi, H

    2014-12-01

    This study investigated the effects of a static stretching (SS) program on muscle hardnesses of the gastrocnemius medialis (MG) and gastrocnemius lateralis (LG). Nineteen young men participated in this study. Either the right or left leg was randomly selected to conduct three bouts of 2-min SS of the plantar flexors 6 days a week for 5 weeks in each subject (the SS group), and the other leg was assigned to a control group. Before (pretest) and after (posttest) conducting the SS program, MG and LG hardnesses were measured using shear wave ultrasound elastography. The SS program was found to decrease muscle hardnesses, but not to change the ratio of MG hardness to LG hardness. There were no significant differences between the relative changes in the MG and LG hardnesses from pretest to posttest in both the SS and control groups. Significant correlations between the muscle hardness ratios at pretest and posttest were found in both groups. The results of this study suggest that the current SS program is useful for improving muscle condition in the plantar flexors, and that its long-term effects on the MG and LG hardnesses are of the same degree. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Achilles tendon length and medial gastrocnemius architecture in children with cerebral palsy and equinus gait.

    Science.gov (United States)

    Wren, Tishya A L; Cheatwood, Allison P; Rethlefsen, Susan A; Hara, Reiko; Perez, Francisco J; Kay, Robert M

    2010-01-01

    The aim of this study was to examine both the tendon and muscle components of the medial gastrocnemius muscle-tendon unit in children with cerebral palsy (CP) and equinus gait, with or without contracture. We also examined a small number of children who had undergone prior surgical lengthening of the triceps surae to address equinus contracture. Ultrasound was used to measure Achilles tendon length and muscle-tendon architectural parameters in children of ages 5 to 12 years. Muscle and tendon parameters were compared among 4 groups: Control group (N=40 limbs from 21 typically developing children), Static Equinus group (N=23 limbs from 15 children with CP and equinus contracture), Dynamic Equinus group (N=12 limbs from 7 children with CP and equinus gait without contracture), and Prior Surgery group (N=10 limbs from 6 children with CP who had prior gastrocnemius recession or tendo-achilles lengthening). The groups were compared using analysis of variance and Scheffe post hoc tests. The CP groups had longer Achilles tendons and shorter muscle bellies than the Control group (Parchitecture. These architectural features likely affect function, possibly contributing to functional deficits such as plantarflexor weakness after surgery. Level II, prospective comparative study.

  18. Repeated bouts of fast velocity eccentric contractions induce atrophy of gastrocnemius muscle in rats.

    Science.gov (United States)

    Ochi, Eisuke; Nosaka, Kazunori; Tsutaki, Arata; Kouzaki, Karina; Nakazato, Koichi

    2015-10-01

    One bout of exercise consisting of fast velocity eccentric contractions has been shown to increase muscle protein degradation in rats. The present study tested the hypothesis that muscle atrophy would be induced after four bouts of fast velocity eccentric contractions, but not after four bouts of slow velocity eccentric contractions. Male Wistar rats were randomly placed into 3 groups; fast (180°/s) velocity (180EC, n = 7), slow (30°/s) velocity eccentric exercise (30EC, n = 7), or sham-treatment group (control, n = 7). The 180EC and 30EC groups received 4 sessions of 4 sets of 5 eccentric contractions of triceps surae muscles by extending the ankle joint during evoked electrical stimulation of the muscles, and the control group had torque measures, every 2 days, and all rats were sacrificed 1 day after the fourth session. Medial and lateral gastrocnemius wet mass were 4-6 % smaller, cross-sectional area of medial gastrocnemius was 6-7% smaller, and isometric tetanic torque of triceps surae muscles was 36 % smaller (p eccentric contractions.

  19. A longitudinal assessment of myoelectric activity, postural sway, and low-back pain during pregnancy.

    Science.gov (United States)

    Moreira, Luciana S; Elias, Leonardo A; Gomide, Adriane B; Vieira, Marcus F; DO Amaral, Waldemar N

    2017-01-01

    The present study aimed at investigating the control of upright quiet standing in pregnant women throughout pregnancy, and whether low-back pain exerts influence on this motor task. Myoelectric signals from postural muscles and stabilometric data were collected from 15 non-pregnant and 15 pregnant women during upright quiet standing. Electromyogram envelopes and center of pressure metrics were evaluated in the control group, as well as in pregnant women in their first and third trimester of pregnancy. A correlation analysis was performed between the measured variables and a low-back pain disability index. Pregnant women exhibited a decreased maximum voluntary isometric activity for all postural muscles evaluated. Additionally, the activity of lumbar muscles during the postural task was significantly higher in the pregnant women in comparison to the non-pregnant controls. The soleus muscle maintained its activity at the same level as the gestation progressed. Higher postural oscillations were observed in the anteroposterior direction while mediolateral sway was reduced in the third trimester of pregnancy. No correlation was detected between the lowback pain disability index and neuromechanical variables. This study provides additional data regarding the functioning and adaptations of the postural control system during pregnancy. Also, we provide further evidence that postural control during quiet standing cannot be used to predict the occurrence of low-back pain. We hypothesize that the modifications in the neural drive to the muscles, as well as in postural sway may be related to changes in the biomechanics and hormonal levels experienced by the pregnant women.

  20. Deep learning-based artificial vision for grasp classification in myoelectric hands

    Science.gov (United States)

    Ghazaei, Ghazal; Alameer, Ali; Degenaar, Patrick; Morgan, Graham; Nazarpour, Kianoush

    2017-06-01

    Objective. Computer vision-based assistive technology solutions can revolutionise the quality of care for people with sensorimotor disorders. The goal of this work was to enable trans-radial amputees to use a simple, yet efficient, computer vision system to grasp and move common household objects with a two-channel myoelectric prosthetic hand. Approach. We developed a deep learning-based artificial vision system to augment the grasp functionality of a commercial prosthesis. Our main conceptual novelty is that we classify objects with regards to the grasp pattern without explicitly identifying them or measuring their dimensions. A convolutional neural network (CNN) structure was trained with images of over 500 graspable objects. For each object, 72 images, at {{5}\\circ} intervals, were available. Objects were categorised into four grasp classes, namely: pinch, tripod, palmar wrist neutral and palmar wrist pronated. The CNN setting was first tuned and tested offline and then in realtime with objects or object views that were not included in the training set. Main results. The classification accuracy in the offline tests reached 85 % for the seen and 75 % for the novel objects; reflecting the generalisability of grasp classification. We then implemented the proposed framework in realtime on a standard laptop computer and achieved an overall score of 84 % in classifying a set of novel as well as seen but randomly-rotated objects. Finally, the system was tested with two trans-radial amputee volunteers controlling an i-limb UltraTM prosthetic hand and a motion controlTM prosthetic wrist; augmented with a webcam. After training, subjects successfully picked up and moved the target objects with an overall success of up to 88 % . In addition, we show that with training, subjects’ performance improved in terms of time required to accomplish a block of 24 trials despite a decreasing level of visual feedback. Significance. The proposed design constitutes a substantial

  1. PPM1B and P-IKKβ expression levels correlated inversely with rat gastrocnemius atrophy after denervation

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jian; Liang, Bing-Sheng [Department of Orthopedics, the Second Hospital, Shanxi Medical University, Taiyuan (China)

    2012-05-18

    Activated inhibitor of nuclear factor-κB kinase β (IKKβ) is necessary and sufficient for denervated skeletal muscle atrophy. Although several studies have shown that Mg{sup 2+}/Mn{sup 2+}-dependent protein phosphatase 1B (PPM1B) inactivated IKKβ, few studies have investigated the role of PPM1B in denervated skeletal muscle. In this study, we aim to explore the expression and significance of PPM1B and phosphorylated IKKβ (P-IKKβ) during atrophy of the denervated gastrocnemius. Thirty young adult female Wistar rats were subjected to right sciatic nerve transection and were sacrificed at 0 (control), 2, 7, 14, and 28 days after denervation surgery. The gastrocnemius was removed from both the denervated and the contralateral limb. The muscle wet weight ratio was calculated as the ratio of the wet weight of the denervated gastrocnemius to that of the contralateral gastrocnemius. RT-PCR and Western blot analysis showed that mRNA and protein levels of PPM1B were significantly lower than those of the control group at different times after the initiation of denervation, while P-IKKβ showed the opposite trends. PPM1B protein expression persistently decreased while P-IKKβ expression persistently increased for 28 days after denervation. PPM1B expression correlated negatively with P-IKKβ expression by the Spearman test, whereas decreasing PPM1B expression correlated positively with the muscle wet weight ratio. The expression levels of PPM1B and P-IKKβ were closely associated with atrophy in skeletal denervated muscle. These results suggest that PPM1B and P-IKKβ could be markers in skeletal muscle atrophy.

  2. PPM1B and P-IKKβ expression levels correlated inversely with rat gastrocnemius atrophy after denervation

    Directory of Open Access Journals (Sweden)

    Jian Wei

    2012-08-01

    Full Text Available Activated inhibitor of nuclear factor-κB kinase β (IKKβ is necessary and sufficient for denervated skeletal muscle atrophy. Although several studies have shown that Mg2+/Mn2+-dependent protein phosphatase 1B (PPM1B inactivated IKKβ, few studies have investigated the role of PPM1B in denervated skeletal muscle. In this study, we aim to explore the expression and significance of PPM1B and phosphorylated IKKβ (P-IKKβ during atrophy of the denervated gastrocnemius. Thirty young adult female Wistar rats were subjected to right sciatic nerve transection and were sacrificed at 0 (control, 2, 7, 14, and 28 days after denervation surgery. The gastrocnemius was removed from both the denervated and the contralateral limb. The muscle wet weight ratio was calculated as the ratio of the wet weight of the denervated gastrocnemius to that of the contralateral gastrocnemius. RT-PCR and Western blot analysis showed that mRNA and protein levels of PPM1B were significantly lower than those of the control group at different times after the initiation of denervation, while P-IKKβ showed the opposite trends. PPM1B protein expression persistently decreased while P-IKKβ expression persistently increased for 28 days after denervation. PPM1B expression correlated negatively with P-IKKβ expression by the Spearman test, whereas decreasing PPM1B expression correlated positively with the muscle wet weight ratio. The expression levels of PPM1B and P-IKKβ were closely associated with atrophy in skeletal denervated muscle. These results suggest that PPM1B and P-IKKβ could be markers in skeletal muscle atrophy.

  3. A new approach to assess the gastrocnemius muscle volume in rodents using ultrasound; comparison with the gastrocnemius muscle index.

    Directory of Open Access Journals (Sweden)

    Tim H J Nijhuis

    Full Text Available INTRODUCTION: The purpose of this study was to determine the reliability and validity of a new non-invasive ultrasound technique to measure gastrocnemius muscle atrophy after nerve denervation in an animal model. METHODS: In sixteen rodents an eight mm sciatic nerve gap was created. In the following 8 weeks, each week, two rodents were euthanized and the gastrocnemius muscle was examined using two different ultrasound systems and two investigators. The standardized ultrasound measurement protocol consisted of identifying pre-defined anatomical landmarks: 1 the fibula, 2 the fibular nerve, and 3 the junction between the most distal point of the semitendinosus muscle and gastrocnemius muscle. Consequently, we measured the muscle thickness as the length of the line between the fibula and the junction between the two muscles, perpendicular to the fibular nerve. After the ultrasound recording, the muscle mass was determined. RESULTS: A steep decline of muscle weight of 24% was observed after one week. In the following weeks, the weight further decreased and then remained stable from 6 weeks onwards, resulting in a maximal muscle weight decrease of 82%. The correlation coefficient was >0.96 between muscle diameter and weight using both ultrasound systems. The inter-rater reliability was excellent for both devices on the operated side (ICC of 0.99 for both ultrasound systems and good for the non-operated site (ICC's: 0.84 & 0.89. The difference between the muscle mass ratio and the muscle thickness ratio was not more than 5% with two outliers of approximately 13%. DISCUSSION: We have developed an innovative, highly reliable technique for quantifying muscle atrophy after nerve injury. This technique allows serial measurements in the same animal over time. This is a significant advantage compared to the conventional technique for quantifying muscle atrophy, which requires sacrificing the animal.

  4. [Myoelectricity study on wearing flat bite plate under different raised distances in deep overbite therapy].

    Science.gov (United States)

    Xu, Jian-Guang; Wang, Xu-Xia; Ren, Xu-Sheng; Zhang, Jun; Li, Na

    2009-06-01

    To analyze changes of myoelectrical activity of anterior funicle of temporal muscle (TA) and masseter muscle (MM) after raising vertical distance of occlusion by flat bite plate during treatment of deep overbite in order to approach an optimal raised vertical distance. A total of 70 persons were selected and divided into two groups: Experiment group (36 patients) with deep overbite and control group (34 persons) with individual normal occlusion. The experiment group was subdivided into three groups that were respectively raised D, D+2 mm and D+4 mm (D means free way space, mm). Electromyologram (EMG) was utilized to measure the average peak potential of TA and MM on quiescent condition before treatment and two weeks after wearing flat bite plate. 1) Before treatment, the average peak potential of experiment group was obviously higher than that of the control group (P<0.05). 2) After two weeks the potential of TA and MM of all persons in experiment group was obviously lower than before (P<0.05), the degree between the group D+2 mm and the group D+4 mm was not manifestly different, but both of the two groups were more obvious than the group D. The raised vertical distance of occlusion by flat bite plate, which exceeded free way space, was favourable to the functional recovery of masticatory muscles.

  5. Myoelectric activity of the small intestine during morphine dependence and withdrawal in rats

    International Nuclear Information System (INIS)

    Kuperman, D.A.; Sninsky, C.A.; Lynch, D.F.

    1987-01-01

    The authors investigated (1) the effect of morphine dependence on the migrating myoelectric complex (MMC) of the small intestine, (2) whether bacterial overgrowth developed in morphine-dependent rats, and (3) the effect of naloxone and methylbromide naltrexone, a peripheral opioid antagonist, on the MMC in morphine-naive and morphine-dependent rats. They also evaluated intestinal motility during naloxone-induced withdrawal in animals pretreated with clonidine. Intestinal myoelectric activity was monitored by four indwelling electrodes in unanesthetized, fasted rats. D-[ 14 C]xylose breath tests were performed before and after morphine-pellet implantation to evaluate the presence of bacterial overgrowth of the small intestine. Naloxone had no effect on myoelectric activity of the small intestine in morphine-naive rats. Cycling activity fronts were present in morphine-dependent animals, but there was a significant prolongation of activity front periodicity and slowing of the propagation velocity. No significant increase in 14 CO 2 excretion was noted in the morphine-dependent rats. They conclude from their studies that (1) myoelectric activity of the small intestine develops incomplete tolerance to morphine; (2) bacterial overgrowth is not a feature of morphine dependence in the rat; (3) alterations of intestinal myoelectric activity are a component of the opiate withdrawal syndrome, and they appear at least partially mediated by a peripheral mechanism that can be suppressed by an α 2 -adrenergic agonist

  6. Myoelectric activity of the small intestine during morphine dependence and withdrawal in rats

    Energy Technology Data Exchange (ETDEWEB)

    Kuperman, D.A.; Sninsky, C.A.; Lynch, D.F.

    1987-04-01

    The authors investigated (1) the effect of morphine dependence on the migrating myoelectric complex (MMC) of the small intestine, (2) whether bacterial overgrowth developed in morphine-dependent rats, and (3) the effect of naloxone and methylbromide naltrexone, a peripheral opioid antagonist, on the MMC in morphine-naive and morphine-dependent rats. They also evaluated intestinal motility during naloxone-induced withdrawal in animals pretreated with clonidine. Intestinal myoelectric activity was monitored by four indwelling electrodes in unanesthetized, fasted rats. D-(/sup 14/C)xylose breath tests were performed before and after morphine-pellet implantation to evaluate the presence of bacterial overgrowth of the small intestine. Naloxone had no effect on myoelectric activity of the small intestine in morphine-naive rats. Cycling activity fronts were present in morphine-dependent animals, but there was a significant prolongation of activity front periodicity and slowing of the propagation velocity. No significant increase in /sup 14/CO/sub 2/ excretion was noted in the morphine-dependent rats. They conclude from their studies that (1) myoelectric activity of the small intestine develops incomplete tolerance to morphine; (2) bacterial overgrowth is not a feature of morphine dependence in the rat; (3) alterations of intestinal myoelectric activity are a component of the opiate withdrawal syndrome, and they appear at least partially mediated by a peripheral mechanism that can be suppressed by an ..cap alpha../sub 2/-adrenergic agonist.

  7. Intermanual transfer in training with an upper-limb myoelectric prosthesis simulator: a mechanistic, randomized, pretest-posttest study.

    Science.gov (United States)

    Romkema, Sietske; Bongers, Raoul M; van der Sluis, Corry K

    2013-01-01

    Intermanual transfer may improve prosthetic handling and acceptance if used in training soon after an amputation. The purpose of this study was to determine whether intermanual transfer effects can be detected after training with a myoelectric upper-limb prosthesis simulator. A mechanistic, randomized, pretest-posttest design was used. A total of 48 right-handed participants (25 women, 23 men) who were able-bodied were randomly assigned to an experimental group or a control group. The experimental group performed a training program of 5 days' duration using the prosthesis simulator. To determine the improvement in skill, a test was administered before, immediately after, and 6 days after training. The control group only performed the tests. Training was performed with the unaffected arm, and tests were performed with the affected arm (the affected arm simulating an amputated limb). Half of the participants were tested with the dominant arm and half with the nondominant arm. Initiation time was defined as the time from starting signal until start of the movement, movement time was defined as the time from the beginning of the movement until completion of the task, and force control was defined as the maximal applied force on a deformable object. The movement time decreased significantly more in the experimental group (F₂,₉₂=7.42, P=.001, η²(G)=.028) when compared with the control group. This finding is indicative of faster handling of the prosthesis. No statistically significant differences were found between groups with regard to initiation time and force control. We did not find a difference in intermanual transfer between the dominant and nondominant arms. The training utilized participants who were able-bodied in a laboratory setting and focused only on transradial amputations. Intermanual transfer was present in the affected arm after training the unaffected arm with a myoelectric prosthesis simulator, and this effect did not depend on laterality. This

  8. The Effect of 8 Weeks High-intensity Interval Training on Myostatin and Follistatin Gene Expression in Gastrocnemius Muscle of the Rats

    Directory of Open Access Journals (Sweden)

    Soheil Biglari

    2018-04-01

    Full Text Available Abstract Background: The purpose of the present study is to investigate the effect of 8 weeks High-intensity Interval Training (HIIT on the expression of two muscle growth regulating genes (myostatin and follistatin in gastrocnemius muscle of healthy male rats. Materials and Methods: 16 male Wistar rats were randomly divided into two groups in the same number: control and HIIT. HIIT program was underwent 40 min each session, three sessions in a week for eight weeks. Each exercise training session consisted of 5 min warm-up and cool-down at 40-50 % VO2max, 30 min interval running including 4 min high-intensity (85-90% VO2max and 2 min active recovery (at 50-60% VO2max. Rats in control group did not do any exercise training program. 48 h after the last training session, rats` gastrocnemius muscle was extracted and the expression of myostatin and follistatin genes was determined by Real Time-PCR. For statistical data analysis, independent t-test was used. Results: The expression of myostatin was significantly reduced 68% in HIIT group in comparison with the control group (p0.05. Gastrocnemius muscle weight was significantly increased 23% in the HIIT group compared to the control group (p<0.05. Conclusion: Results indicated that HIIT lead to significant reduction in the expression of myostatin gene and increase in the weight of gastrocnemius muscle in rats.

  9. Effects of muscle fatigue on the usability of a myoelectric human-computer interface.

    Science.gov (United States)

    Barszap, Alexander G; Skavhaug, Ida-Maria; Joshi, Sanjay S

    2016-10-01

    Electromyography-based human-computer interface development is an active field of research. However, knowledge on the effects of muscle fatigue for specific devices is limited. We have developed a novel myoelectric human-computer interface in which subjects continuously navigate a cursor to targets by manipulating a single surface electromyography (sEMG) signal. Two-dimensional control is achieved through simultaneous adjustments of power in two frequency bands through a series of dynamic low-level muscle contractions. Here, we investigate the potential effects of muscle fatigue during the use of our interface. In the first session, eight subjects completed 300 cursor-to-target trials without breaks; four using a wrist muscle and four using a head muscle. The wrist subjects returned for a second session in which a static fatiguing exercise took place at regular intervals in-between cursor-to-target trials. In the first session we observed no declines in performance as a function of use, even after the long period of use. In the second session, we observed clear changes in cursor trajectories, paired with a target-specific decrease in hit rates. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Initiation of the migrating myoelectric complex in dogs.

    Science.gov (United States)

    Bueno, L; Rayner, V; Ruckebusch, Y

    1981-01-01

    1. Contractile and spike activity in the conscious dog were recorded from strain gauge force transducers and electrodes chronically implanted on the antrum, duodenum and jejunum. The pattern of activity was related to the time elapsed after feeding a daily meal, both in intact dogs and in dogs with antro-jejunal or oesophago-duodenal anastomoses. 2. From 8 to 10 h after feeding, transient reductions of the continuous antral spiking activity were recorded while phases of regular spiking activity (RSA) and contractions developed on the proximal intestine. 3. About 18 h after feeding, the post-prandial antral activity became intermittent, each period of contractions being accompanied by the duodenal development of a RSA phase. 4. The RSA phases were still initiated on the duodenum after an antro-jejunal anastomosis and after gastrectomy. 5. It is concluded that phases of RSA of the migrating myoelectric complex are initiated in the proximal part of the small intestine rather than in the stomach. It is suggested that the RSA phase exerts an inhibitory effect on the antrum which may serve to reduce the flow of digesta through the pylorus when the ability of the duodenum to receive chyme is restricted. PMID:7320868

  11. Hand Functions of Myoelectric and 3D-Printed Pressure-Sensored Prosthetics: A Comparative Study.

    Science.gov (United States)

    Lee, Kyu Ho; Bin, Hobeom; Kim, KeunBae; Ahn, So Young; Kim, Bong-Ok; Bok, Soo-Kyung

    2017-10-01

    The loss of an upper limb significantly limits the functional activities of daily living. A huge emphasis is placed on the manipulation, shape, weight, and comfort of a prosthesis, to enable its use as an inherent body part. Even with technological advances, customized upper-extremity myoelectric prosthesis remain heavy and expensive. The high cost of upper-extremity prosthesis is an especially steep economic barrier for patients. Three-dimensional (3D) printing is a promising avenue for reducing the cost of prosthesis. We applied 3D-printed pressure-sensored prosthetics to a traumatic transradial amputee, and compared the hand functions with a customized myoelectric prosthesis. The 3D-printed pressure-sensored prosthetics showed low grip strength and decreased dexterity compared to the conventional myoelectric prosthesis. Although there were a few limitations, the fabrication of prosthesis with 3D printing technology can overcome previous problems such as high production cost, long fabrication period and heavy weight.

  12. Gastrocnemius Recession Leads to Increased Ankle Motion and Improved Patient Satisfaction After 2 Years of Follow-Up

    DEFF Research Database (Denmark)

    Holtmann, Julia Alessandra; Südkamp, Norbert P; Schmal, Hagen

    2017-01-01

    The isolated gastrocnemius contracture present in neurologic healthy patients results in a significant limitation of ankle dorsiflexion causing pathologic gait patterns and a greater risk of further foot disorders. Gastrocnemius recession is an established procedure to increase ankle dorsiflexion...

  13. The Effects of Ligustrazine on the Ca2+ Concentration of Soleus and Gastrocnemius Muscle Fibers in Hindlimb Unloaded Rat

    Science.gov (United States)

    Gao, Yunfang; Goswami, Nandu; Du, Bei; Hu, Huanxin; Wu, Xue

    Background Spaceflight or inactivity (bed rest, limb immobilization, hindlimb unloading) causes skeletal muscle atrophy. Recent studies show that an increase in protein degradation is an important mechanism for disuse atrophy. Furthermore, the calcium overload of disuse-atrophied muscle fiber has been shown to initiate the skeletal muscle proteolysis in disuse atrophy. Ligustrazine (tetramethylpyrazine, TMP), one of the important active ingredient extracted from Chuanxiong, has been shown by our group to increase muscle fiber cross-sectional area in atrophied soleus induced by 14 days hindlimb unloading. However, the underlying mechanisms of ligustrazine effects on disuse-atrophied muscle fibers remain unknown. Objective: We investigated the effects of ligustrazine on the cytoplasmic calcium overloading in soleus and gastrocnemius in 14 days hindlimb unloaded (HU) rats. Methods: Adult female Sprague-Dawley rats were matched for body mass and randomly assigned to three groups (n=8, each group): 1) synchronous control (CON); HU + intragastric water instillation (HU+W); HU + intragastric 60.0 mg kg-1 ligustrazine instillation (HU+Tmp). Laser scanning confocal microscope assessed the concentrations of cytoplasmic calcium ions. Spaceflight disuse atrophy was simulated by hindlimb unloading, provided by tail suspension. Results: 1) Compared with CON, the concentration of soleus intracellular calcium ion in HU+W and HU+Tmp increased 330% and 86% respectively P<0.01). Compared with HU+W, the concentration of soleus intracellular calcium ion in HU+Tmp decreased by 130% P<0.01). 2) Compared with CON, the concentration of gastrocnemius intracellular calcium ion in HU+W and HU+Tmp increased 189.8% and 32.1% respectively P<0.01). Compared with HU+W, the concentration of gastrocnemius intracellular calcium ion in HU+Tmp decreased by 119.3% (P<0.01). Conclusion: After 14 days of hindlimb unloading, cytoplasmic calcium of soleus (slow-twitch muscle) and gastrocnemius (fast

  14. MYOELECTRIC ALTERATIONS AFTER VOLUNTARY INDUCED HIGH - AND LOW - FREQUENCY FATIGUE

    Directory of Open Access Journals (Sweden)

    Vojko Strojnik

    2008-06-01

    Full Text Available The aim of the study was to find whether voluntary induced high- and low-frequency peripheral fatigue exhibit specific alteration in surface EMG signal (SEMG during evoked and maximum voluntary contractions. Ten male students of physical education performed 60 s long stretch-shortening cycle (SSC exercise with maximal intensity and 30 s long concentric (CON exercise with maximal intensity. To verify voluntary induced peripheral fatigue, knee torques during low- (T20 and high-frequency electrical stimulation (T100 of relaxed vastus lateralis muscle (VL were obtained. Contractile properties of the VL were measured with passive twitch and maximal voluntary knee extension test (MVC. Changes in M-waves and SEMG during MVC test were used to evaluate the differences in myoelectrical signals. T100/T20 ratio decreased by 10.9 ± 8.4 % (p < 0.01 after the SSC exercise and increased by 35.9 ± 17.5 % (p < 0.001 after the CON exercise. Significant SEMG changes were observed only after the CON exercise where peak to peak time of the M-waves increased by 9.2 ± 13.3 % (p < 0.06, SEMG amplitude during MVC increased by 32.9 ± 21.6 % (p < 0.001 and SEMG power spectrum median frequency decreased by 11.0 ± 10.5 % (p < 0.05. It is concluded that high frequency fatigue wasn't reflected in SEMG, however the SEMG changes after the CON seemed to reflect metabolic changes due to acidosis

  15. Hamstring myoelectrical activity during three different kettlebell swing exercises.

    Science.gov (United States)

    Del Monte, Michael J; Opar, David A; Timmins, Ryan G; Ross, James; Keogh, Justin Wl; Lorenzen, Christian

    2017-09-11

    Kettlebell exercises have become an increasingly popular form of resistance training and component of lower body rehabilitative training programs; despite a lack of scientific literature illustrating internal mechanisms and effectiveness of these approaches. Participants (n=14) performed three different styles of kettlebell swings (hip hinge, squat and double knee extension) and were assessed for medial hamstrings (MH) and biceps femoris (BF) myoelectrical activity via surface electromyography (sEMG). Bipolar pre-gelled Ag/AgCl surface electromyography (sEMG) electrodes (10mm diameter, 20mm inter-electrode distance) were placed on the participant's dominant limb after correct skin preparation.There was a main effect for swing type (p = 0.004), where the hip hinge swing elicited a greater overall MH and BF sEMG in comparison to the squat swing (mean difference = 3.92; 95% CI = 1.53 to 6.32; p = 0.002) and the double knee extension swing (mean difference = 5.32; 95% CI = 0.80 to 9.83; p = 0.020). Across all swing types, normalised percentage of MH sEMG was significantly higher compared to the BF (mean difference = 9.93; 95% CI = 1.67 to 18.19; p = 0.022). The hip hinge kettlebell swing produced the greatest amount of hamstring sEMG for the three styles of kettlebell swings assessed. These findings have implications for the application of kettlebell swing exercises in strength and conditioning, injury prevention and rehabilitation programs.

  16. Calpain 3 Expression Pattern during Gastrocnemius Muscle Atrophy and Regeneration Following Sciatic Nerve Injury in Rats

    Directory of Open Access Journals (Sweden)

    Ronghua Wu

    2015-11-01

    Full Text Available Calpain 3 (CAPN3, also known as p94, is a skeletal muscle-specific member of the calpain family that is involved in muscular dystrophy; however, the roles of CAPN3 in muscular atrophy and regeneration are yet to be understood. In the present study, we attempted to explain the effect of CAPN3 in muscle atrophy by evaluating CAPN3 expression in rat gastrocnemius muscle following reversible sciatic nerve injury. After nerve injury, the wet weight ratio and cross sectional area (CSA of gastrocnemius muscle were decreased gradually from 1–14 days and then recovery from 14–28 days. The active form of CAPN3 (~62 kDa protein decreased slightly on day 3 and then increased from day 7 to 14 before a decrease from day 14 to 28. The result of linear correlation analysis showed that expression of the active CAPN3 protein level was negatively correlated with muscle wet weight ratio. CAPN3 knockdown by short interfering RNA (siRNA injection improved muscle recovery on days 7 and 14 after injury as compared to that observed with control siRNA treatment. Depletion of CAPN3 gene expression could promote myoblast differentiation in L6 cells. Based on these findings, we conclude that the expression pattern of the active CAPN3 protein is linked to muscle atrophy and regeneration following denervation: its upregulation during early stages may promote satellite cell renewal by inhibiting differentiation, whereas in later stages, CAPN3 expression may be downregulated to stimulate myogenic differentiation and enhance recovery. These results provide a novel mechanistic insight into the role of CAPN3 protein in muscle regeneration after peripheral nerve injury.

  17. Calpain 3 Expression Pattern during Gastrocnemius Muscle Atrophy and Regeneration Following Sciatic Nerve Injury in Rats.

    Science.gov (United States)

    Wu, Ronghua; Yan, Yingying; Yao, Jian; Liu, Yan; Zhao, Jianmei; Liu, Mei

    2015-11-11

    Calpain 3 (CAPN3), also known as p94, is a skeletal muscle-specific member of the calpain family that is involved in muscular dystrophy; however, the roles of CAPN3 in muscular atrophy and regeneration are yet to be understood. In the present study, we attempted to explain the effect of CAPN3 in muscle atrophy by evaluating CAPN3 expression in rat gastrocnemius muscle following reversible sciatic nerve injury. After nerve injury, the wet weight ratio and cross sectional area (CSA) of gastrocnemius muscle were decreased gradually from 1-14 days and then recovery from 14-28 days. The active form of CAPN3 (~62 kDa) protein decreased slightly on day 3 and then increased from day 7 to 14 before a decrease from day 14 to 28. The result of linear correlation analysis showed that expression of the active CAPN3 protein level was negatively correlated with muscle wet weight ratio. CAPN3 knockdown by short interfering RNA (siRNA) injection improved muscle recovery on days 7 and 14 after injury as compared to that observed with control siRNA treatment. Depletion of CAPN3 gene expression could promote myoblast differentiation in L6 cells. Based on these findings, we conclude that the expression pattern of the active CAPN3 protein is linked to muscle atrophy and regeneration following denervation: its upregulation during early stages may promote satellite cell renewal by inhibiting differentiation, whereas in later stages, CAPN3 expression may be downregulated to stimulate myogenic differentiation and enhance recovery. These results provide a novel mechanistic insight into the role of CAPN3 protein in muscle regeneration after peripheral nerve injury.

  18. Fermented Rice Germ Extract Alleviates Morphological and Functional Damage to Murine Gastrocnemius Muscle by Inactivation of AMP-Activated Protein Kinase.

    Science.gov (United States)

    Tanaka, Miyu; Yoshino, Yuta; Takeda, Shogo; Toda, Kazuya; Shimoda, Hiroshi; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

    2017-10-01

    Sarcopenia, loss of muscle mass and function, is mainly observed in elderly people. In this study, we investigated whether fermented rice germ extract (FRGE) has some effects on the mouse gastrocnemius muscle by using behavioral and morphological analyses, Western blotting, and a murine model of immobilization-induced muscle atrophy. Daily oral FRGE administration increased muscle weight and strength. In addition, myofiber size in gastrocnemius muscle of FRGE-treated mice was increased as revealed by morphological quantification. Activation of AMP-activated protein kinase (AMPK) signaling, which inhibits protein synthesis and stimulates protein degradation in gastrocnemius muscle, was significantly attenuated in the FRGE-treated mice compared with control mice. Expression level of forkhead box 3a (FOXO3a) protein was also significantly decreased in the FRGE-treated group. Moreover, the decrease in mean myofiber cross-sectional area in immobilized hindlimb in vehicle-treated mice was inhibited by FRGE treatment in histological analysis. In conclusion, FRGE increased the strength and weight of gastrocnemius muscle and myofiber size, and reduced immobilization-induced muscle atrophy in mice. These findings indicated that FRGE might be beneficial in preventing motor dysfunction in a range of conditions, including sarcopenia.

  19. ANATOMICAL VARIATIONS OF THE GASTROCNEMIUS MUSCLE- A DISSECTION-BASED STUDY

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    Rajat Dutta Roy

    2017-11-01

    Full Text Available BACKGROUND In human, the bulk of the posterior compartment of the leg is formed by the gastrocnemius and the soleus muscle. The superficially-placed gastrocnemius is a bipennate muscle, but according to available literature, it exhibits numerous anatomical variations. The aim of the present study is to find out the anatomical variations of the gastrocnemius muscle in this part of Assam. MATERIALS AND METHODS The present study undertaken in the Department of Anatomy, Jorhat Medical College, from August 2014 to August 2017 included 30 lower limbs from 15 embalmed cadavers of known sexes. These cadavers were provided to the first year MBBS students for routine dissection procedure. After carrying out the dissection as per Cunningham’s Manual of Practical Anatomy, the gastrocnemius muscle was examined for its two heads of origin. Any accessory heads found were noted and recorded. RESULTS Out of the 30 lower limb specimens, 28 (93.33% limbs presented with the normal two-headed gastrocnemius muscle, while 2 (6.66% limbs (1 right and 1 left, presented with four-headed gastrocnemius muscle. Both these limbs belonged to male cadavers. CONCLUSION The precise knowledge of occurrence of multi-headed gastrocnemius muscle should be kept in mind, while performing myocutaneous flaps around the knee joint and also during limb salvage procedures or limb sparing surgery.

  20. Changes in performance over time while learning to use a myoelectric prosthesis

    NARCIS (Netherlands)

    Bouwsema, Hanneke; van der Sluis, Corry K.; Bongers, Raoul M.

    2014-01-01

    Background: Training increases the functional use of an upper limb prosthesis, but little is known about how people learn to use their prosthesis. The aim of this study was to describe the changes in performance with an upper limb myoelectric prosthesis during practice. The results provide a basis

  1. Grasping force and slip feedback through vibrotactile stimulation to be used in myoelectric forearm prostheses

    NARCIS (Netherlands)

    Muijzer-Witteveen, Heintje Johanna Berendina; Rietman, Johan Swanik; Veltink, Petrus H.

    User feedback about grasping force or slip of objects is lacking in current myoelectric forearm prostheses, resulting in a high number of prosthesis abandonment, because a high level of concentration is required to hold an object. Several approaches to provide force feedback to the user via

  2. Gestational Protein Restriction Impairs Insulin-Regulated Glucose Transport Mechanisms in Gastrocnemius Muscles of Adult Male Offspring

    Science.gov (United States)

    Blesson, Chellakkan S.; Sathishkumar, Kunju; Chinnathambi, Vijayakumar

    2014-01-01

    Type II diabetes originates from various genetic and environmental factors. Recent studies showed that an adverse uterine environment such as that caused by a gestational low-protein (LP) diet can cause insulin resistance in adult offspring. The mechanism of insulin resistance induced by gestational protein restriction is not clearly understood. Our aim was to investigate the role of insulin signaling molecules in gastrocnemius muscles of gestational LP diet–exposed male offspring to understand their role in LP-induced insulin resistance. Pregnant Wistar rats were fed a control (20% protein) or isocaloric LP (6%) diet from gestational day 4 until delivery and a normal diet after weaning. Only male offspring were used in this study. Glucose and insulin responses were assessed after a glucose tolerance test. mRNA and protein levels of molecules involved in insulin signaling were assessed at 4 months in gastrocnemius muscles. Muscles were incubated ex vivo with insulin to evaluate insulin-induced phosphorylation of insulin receptor (IR), Insulin receptor substrate-1, Akt, and AS160. LP diet-fed rats gained less weight than controls during pregnancy. Male pups from LP diet–fed mothers were smaller but exhibited catch-up growth. Plasma glucose and insulin levels were elevated in LP offspring when subjected to a glucose tolerance test; however, fasting levels were comparable. LP offspring showed increased expression of IR and AS160 in gastrocnemius muscles. Ex vivo treatment of muscles with insulin showed increased phosphorylation of IR (Tyr972) in controls, but LP rats showed higher basal phosphorylation. Phosphorylation of Insulin receptor substrate-1 (Tyr608, Tyr895, Ser307, and Ser318) and AS160 (Thr642) were defective in LP offspring. Further, glucose transporter type 4 translocation in LP offspring was also impaired. A gestational LP diet leads to insulin resistance in adult offspring by a mechanism involving inefficient insulin-induced IR, Insulin receptor

  3. Gestational protein restriction impairs insulin-regulated glucose transport mechanisms in gastrocnemius muscles of adult male offspring.

    Science.gov (United States)

    Blesson, Chellakkan S; Sathishkumar, Kunju; Chinnathambi, Vijayakumar; Yallampalli, Chandrasekhar

    2014-08-01

    Type II diabetes originates from various genetic and environmental factors. Recent studies showed that an adverse uterine environment such as that caused by a gestational low-protein (LP) diet can cause insulin resistance in adult offspring. The mechanism of insulin resistance induced by gestational protein restriction is not clearly understood. Our aim was to investigate the role of insulin signaling molecules in gastrocnemius muscles of gestational LP diet-exposed male offspring to understand their role in LP-induced insulin resistance. Pregnant Wistar rats were fed a control (20% protein) or isocaloric LP (6%) diet from gestational day 4 until delivery and a normal diet after weaning. Only male offspring were used in this study. Glucose and insulin responses were assessed after a glucose tolerance test. mRNA and protein levels of molecules involved in insulin signaling were assessed at 4 months in gastrocnemius muscles. Muscles were incubated ex vivo with insulin to evaluate insulin-induced phosphorylation of insulin receptor (IR), Insulin receptor substrate-1, Akt, and AS160. LP diet-fed rats gained less weight than controls during pregnancy. Male pups from LP diet-fed mothers were smaller but exhibited catch-up growth. Plasma glucose and insulin levels were elevated in LP offspring when subjected to a glucose tolerance test; however, fasting levels were comparable. LP offspring showed increased expression of IR and AS160 in gastrocnemius muscles. Ex vivo treatment of muscles with insulin showed increased phosphorylation of IR (Tyr972) in controls, but LP rats showed higher basal phosphorylation. Phosphorylation of Insulin receptor substrate-1 (Tyr608, Tyr895, Ser307, and Ser318) and AS160 (Thr642) were defective in LP offspring. Further, glucose transporter type 4 translocation in LP offspring was also impaired. A gestational LP diet leads to insulin resistance in adult offspring by a mechanism involving inefficient insulin-induced IR, Insulin receptor

  4. Long-term decoding of movement force and direction with a wireless myoelectric implant

    Science.gov (United States)

    Morel, Pierre; Ferrea, Enrico; Taghizadeh-Sarshouri, Bahareh; Marcel Cardona Audí, Josep; Ruff, Roman; Hoffmann, Klaus-Peter; Lewis, Sören; Russold, Michael; Dietl, Hans; Abu-Saleh, Lait; Schroeder, Dietmar; Krautschneider, Wolfgang; Meiners, Thomas; Gail, Alexander

    2016-02-01

    Objective. The ease of use and number of degrees of freedom of current myoelectric hand prostheses is limited by the information content and reliability of the surface electromyography (sEMG) signals used to control them. For example, cross-talk limits the capacity to pick up signals from small or deep muscles, such as the forearm muscles for distal arm amputations, or sites of targeted muscle reinnervation (TMR) for proximal amputations. Here we test if signals recorded from the fully implanted, induction-powered wireless Myoplant system allow long-term decoding of continuous as well as discrete movement parameters with better reliability than equivalent sEMG recordings. The Myoplant system uses a centralized implant to transmit broadband EMG activity from four distributed bipolar epimysial electrodes. Approach. Two Rhesus macaques received implants in their backs, while electrodes were placed in their upper arm. One of the monkeys was trained to do a cursor task via a haptic robot, allowing us to control the forces exerted by the animal during arm movements. The second animal was trained to perform a center-out reaching task on a touchscreen. We compared the implanted system with concurrent sEMG recordings by evaluating our ability to decode time-varying force in one animal and discrete reach directions in the other from multiple features extracted from the raw EMG signals. Main results. In both cases, data from the implant allowed a decoder trained with data from a single day to maintain an accurate decoding performance during the following months, which was not the case for concurrent surface EMG recordings conducted simultaneously over the same muscles. Significance. These results show that a fully implantable, centralized wireless EMG system is particularly suited for long-term stable decoding of dynamic movements in demanding applications such as advanced forelimb prosthetics in a wide range of configurations (distal amputations, TMR).

  5. Radiofrequency volume reduction of gastrocnemius muscle hypertrophy for cosmetic purposes.

    Science.gov (United States)

    Park, Young Jin; Jo, Yong Woo; Bang, Sa Ik; Kim, Hyung Joon; Lim, So Young; Mun, Goo Hyun; Hyon, Won Sok; Oh, Kap Sung

    2007-01-01

    Muscularly prominent calves, caused mainly by hypertrophy of the gastrocnemius muscle (GCM), are prevalent among Asian women, and this condition can be a significant factor leading to psychological stress. The authors have devised a method for contouring the calf using radiofrequency (RF) applications to the GCMs to correct thick, muscular legs. This study was performed to investigate the effects of RF energy in reducing enlarged GCMs for 250 patients (249 women and 1 man) who sought aesthetic consultation for problems such as thick, muscular, asymmetric, or bowed calves. The operations were performed from June 2004 to April 2006. The patients first received a local anesthetic and sedation. After application of RF current, the prominent muscular contours improved, and the GCMs were contoured to an appropriate proportional volume. The range of the reductions in the calf circumferences at their thickest levels was 1 to 6 cm (mean, 2.5 cm) during the follow-up visits 6 months after the procedures. Most of the patients could return to their activities of daily living, except for exercise, after 1 to 7 days, and they were satisfied with the improved aesthetic contour lines of their lower legs. Clinical photography and ultrasonic examination were performed, and the leg circumferences were measured. Radiofrequency-induced coagulation tissue necrosis of the muscles caused no functional disabilities, and the clinical improvement was well maintained after the treatments for up to 17 months of follow-up evaluation.

  6. Time-Course of Muscle Mass Loss, Damage, and Proteolysis in Gastrocnemius following Unloading and Reloading: Implications in Chronic Diseases.

    Directory of Open Access Journals (Sweden)

    Alba Chacon-Cabrera

    Full Text Available Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization.Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations, proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days of non-invasive hindlimb immobilization (plastic splint, I cohorts and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts following a seven-day period of immobilization. Groups of control animals were also used.Compared to non-exposed controls, muscle weight, limb strength, slow- and fast-twitch cross-sectional areas, mtDNA/nDNA, and myosin content were decreased in mice of I cohorts, whereas tyrosine release, ubiquitin-proteasome activity, muscle injury and systemic troponin I levels were increased. Gastrocnemius reloading following splint removal improved muscle mass loss, strength, fiber atrophy, injury, myosin content, and mtDNA/nDNA, while reducing ubiquitin-proteasome activity and proteolysis.A consistent program of molecular and cellular events leading to reduced gastrocnemius muscle mass and mitochondrial content and reduced strength, enhanced proteolysis, and injury, was seen in this non-invasive mouse model of disuse muscle atrophy. Unloading of the muscle following removal of the splint significantly improved the alterations seen during unloading, characterized by a specific kinetic profile of molecular events involved in muscle regeneration. These findings have implications in patients with chronic diseases including cancer in whom physical activity may be severely compromised.

  7. Time-Course of Muscle Mass Loss, Damage, and Proteolysis in Gastrocnemius following Unloading and Reloading: Implications in Chronic Diseases

    Science.gov (United States)

    Chacon-Cabrera, Alba; Lund-Palau, Helena; Gea, Joaquim; Barreiro, Esther

    2016-01-01

    Background Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization. Methods Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations), proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days) of non-invasive hindlimb immobilization (plastic splint, I cohorts) and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts) following a seven-day period of immobilization. Groups of control animals were also used. Results Compared to non-exposed controls, muscle weight, limb strength, slow- and fast-twitch cross-sectional areas, mtDNA/nDNA, and myosin content were decreased in mice of I cohorts, whereas tyrosine release, ubiquitin-proteasome activity, muscle injury and systemic troponin I levels were increased. Gastrocnemius reloading following splint removal improved muscle mass loss, strength, fiber atrophy, injury, myosin content, and mtDNA/nDNA, while reducing ubiquitin-proteasome activity and proteolysis. Conclusions A consistent program of molecular and cellular events leading to reduced gastrocnemius muscle mass and mitochondrial content and reduced strength, enhanced proteolysis, and injury, was seen in this non-invasive mouse model of disuse muscle atrophy. Unloading of the muscle following removal of the splint significantly improved the alterations seen during unloading, characterized by a specific kinetic profile of molecular events involved in muscle regeneration. These findings have implications in patients with chronic diseases including cancer in whom physical activity may be severely compromised. PMID

  8. Myoelectric activity of the muscular layer of the abdominal aorta in pigs in vivo

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    Albert Czerski

    2012-01-01

    Full Text Available The study was conducted on 5 pigs weighing 20–30 kg. Bipolar electrodes were surgically implanted into the muscular layer of the vascular smooth muscle cell of the abdominal aorta just below the renal arteries. Myoelectric activity characterized by the appearance of changes of membrane potential was found. Changes of potential could be divided according to the amplitude, duration and frequency into first-, second- and third-order waves. First-order waves appeared with a mean frequency of 128 ± 14/min. The mean wave amplitude was 0.150 ± 0.03 mV, and the mean duration was 0.43 ± 0.05 s. They were closely correlated with the electrocardiogram and blood pressure changes. Second-order waves appeared with a mean frequency of 15.9 ± 4.4/min. They were characterized by a mean duration of 2.69 ± 1.5 s. The mean amplitude of the discharge was 0.205 ± 0.157 mV for the second-order wave, they were correlated with the animal’s respiratory action. Third-order waves appeared with a mean frequency of 4.03 ± 1.07/ min. They were characterized by a mean duration of 11.81 ± 5.3 s. The mean amplitude of the discharge was 0.345 ± 0.232 mV for the third-order wave and they were associated with the autonomic control of the lumen of the blood vessel. For the first time the usefulness of the electromyography method in monitoring changes in the vascular smooth muscle cell of pig abdominal aorta was proved.

  9. Content of selected amino acids in the gastrocnemius muscle during experimental hypothyroidism in rats

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    Gołyński Marcin

    2016-12-01

    Full Text Available Introduction: Thyroid hormones affect protein turnover, and in the case of hypothyroidism a decrease in protein synthesis and reduced release of certain amino acids from skeletal muscles are observed. Changes in the amino acid system of skeletal muscles may be responsible for the occurrence of muscle disorders. Material and Methods: The study measured the content of selected amino acids in the gastrocnemius muscle of Wistar rats during experimental hypothyroidism induced by oral administration of methimazole at a concentration of 0.05% in drinking water for 90 d. The rats were divided into four groups: E1 (n = 6 - experimental males, E2 (n = 6 - experimental females, C1 (n = 6 - control males, and C2 (n = 6 control females. Results: A statistically significant reduction occurred in leucine, isoleucine, and 1-methylhistidine levels in males, and 1-methylhistidine in females, in comparison to the control groups. Conclusion: The hypothyroidism-induced changes in amino acid content may be responsible for the occurrence of skeletal muscle function disorders.

  10. Effects of concurrent training on oxidative capacity in rat gastrocnemius muscle.

    Science.gov (United States)

    Furrer, Regula; DE Haan, Arnold; Bravenboer, Nathalie; Kos, Dorien; Lips, Paul; Jaspers, Richard T

    2013-09-01

    Training for improvement of oxidative capacity of muscle fibers may be attenuated when concurrently training for peak power. However, because of fiber type-specific recruitment, such attenuation may only account for high-oxidative muscle fibers. Here, we investigate the effects of concurrent training on oxidative capacity (as measured by succinate dehydrogenase (SDH) activity) by using task-specific recruitment of the high- and low-oxidative compartment of rat medial gastrocnemius muscle (GM). Forty rats were subjected to 6 wk of peak power training (PT, n = 10), endurance training (ET, n = 10), concurrent peak power and endurance training (PET, n = 10), or no training (control, n = 10). SDH activity, mRNA expression of SDH, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), receptor-interacting protein 140, and BCL2/adenovirus E1B 19 kDa-interacting protein 3 as well as PGC-1α protein levels were analyzed in the low- and high-oxidative region of the GM. In the low-oxidative compartment, PT and PET induced a 30% decrease in SDH activity of Type IIB fibers compared with controls and ET (P training attenuated transcription of mRNA for mitochondrial proteins in high-oxidative muscle fibers. In low-oxidative Type IIB fibers, peak power training substantially decreased SDH activity, which was not related to lower SDH mRNA levels. It is concluded that PT and PET enhanced mitochondrial degradation in the low-oxidative compartment of rat GM.

  11. Ankle Power and Endurance Outcomes Following Isolated Gastrocnemius Recession for Achilles Tendinopathy.

    Science.gov (United States)

    Nawoczenski, Deborah A; DiLiberto, Frank E; Cantor, Maxwell S; Tome, Josh M; DiGiovanni, Benedict F

    2016-07-01

    Studies have demonstrated improved ankle dorsiflexion and pain reduction following a gastrocnemius recession (GR) procedure. However, changes in muscle performance during functional activities are not known. The purpose of this study was to determine the effect of an isolated GR on ankle power and endurance in patients with Achilles tendinopathy. Fourteen patients with chronic unilateral Achilles tendinopathy and 10 healthy controls participated in this study. Patient group data were collected 18 months following GR. Pain was compared to preoperative values using a 10-cm visual analog scale (VAS). Patient-reported outcomes for activities of daily living (ADL) and sports were assessed using the Foot and Ankle Ability Measure (FAAM). Kinematic and kinetic data were collected during gait, stair ascent (standard and high step), and repetitive single-limb heel raises. Between-group and side-to-side differences in ankle plantarflexor muscle power and endurance were evaluated with appropriate t tests. Compared with preoperative data, VAS pain scores were reduced (pre 6.8, post 1.6, P tendinopathy who failed nonoperative interventions. There were good patient-reported outcomes for activities of daily living. However, compared to controls, ankle plantarflexion power and endurance deficits in the GR group were noted. The functional implications of the muscle performance deficits are unclear, but may be reflective of patients' self-reported difficulty during more challenging activities. Level III, comparative study. © The Author(s) 2016.

  12. The effect of kinesio tape application on hamstring and gastrocnemius muscles in healthy young adults.

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    Lumbroso, Dedi; Ziv, Elad; Vered, Elisha; Kalichman, Leonid

    2014-01-01

    Scarce evidence exists about effectiveness and mechanisms of action of Kinesio tape (KT) application. To evaluate the effect of KT application over the gastrocnemius or hamstring on range of motion and peak force. Thirty-six physical therapy students participated (18 per group). KT was applied with 30% tension for 48 h to: Group 1 - the gastrocnemius; Group 2 - the hamstrings. The straight leg raise (SLR), knee extension angle (KEA), weight bearing ankle dorsiflexion, gastrocnemius, quadriceps and hamstrings peak forces were evaluated prior to application, 15 min and 48 h after. A significant increase of peak force in the gastrocnemius group appeared immediately and two days later; no immediate change of peak force in the hamstrings group, however, two days later, peak force significantly increased. SLR and ankle dorsiflexion increased immediately in the gastrocnemius group; KEA improved significantly only after two days. It is possible that certain muscles react differently when KT is applied, and the effect may be subsequently detected. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Clinical, radiographic, and magnetic resonance imaging findings of gastrocnemius musculotendinopathy in various dog breeds.

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    Kaiser, Susanne M; Harms, Oliver; Konar, Martin; Staudacher, Anne; Langer, Anna; Thiel, Cetina; Kramer, Martin; Schaub, Sebastian; von Pückler, Kerstin H

    2016-11-23

    To describe clinical, radiographic, and magnetic resonance imaging (MRI) findings in 16 dogs diagnosed with gastrocnemius musculotendinopathy. Retrospective evaluation of medical records, radiographs, and MRI results, as well as follow-up completed by telephone questionnaire. Most dogs had chronic hindlimb lameness with no history of trauma or athletic activities. Clinical examination revealed signs of pain on palpation without stifle joint instability. Seven dogs had radiographic signs of osteophyte formation on the lateral fabella. Magnetic resonance imaging revealed T2 hyperintensity and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. Changes were found in the lateral and medial heads of the gastrocnemius. Conservative treatment resulted in return to full function in 11 dogs. Two dogs showed partial restoration of normal function, one dog showed no improvement. Two dogs were lost to follow-up. Gastrocnemius musculotendinopathy is a potential cause of chronic hindlimb lameness in medium to large breed dogs. A history of athletic activity must not necessarily be present. Magnetic resonance imaging shows signal changes and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. A combination of T1 pre- and post-contrast administration and T2 weighted sequences completed by a fat-suppressed sequence in the sagittal plane are well-suited for diagnosis. Conservative treatment generally results in return to normal function.

  14. Effect of aging on properties of motor unit action potentials in the rat medial gastrocnemius muscle.

    Science.gov (United States)

    Krutki, Piotr; Ciechanowicz-Kowalczyk, Iwona; Łochyński, Dawid; Celichowski, Jan

    2013-10-01

    The purpose of this study was to investigate whether age-related changes in motor unit (MU) contractile properties are reflected in parameters of motor unit action potentials (MUAPs). MUs of the medial gastrocnemius muscle were functionally isolated in anaesthetized Wistar rats. A control group of young animals (5-10mo) was compared to two groups of old rats (24-25mo and 28-30mo). The basic contractile properties of MUs as well as the amplitude, total duration, peak-to-peak time, and number of turns within MUAPs were measured. Effects of aging were mainly observed for fast fatigable MUs (a prolongation of MUAPs and increased number of turns). The MUAP amplitude did not change significantly with aging in either MU type, but it correlated to the twitch or tetanic forces, which tended to increase with age, especially for slow MUs. We concluded that the prolongation of MUAPs and the greater incidence of signal turns was probably a result of a decrease in muscle fiber conduction velocity and/or an increase in their dispersion, and enlargement of MU territories - presumably caused by axonal sprouting of surviving motoneurons. The latter might also be responsible for the observed age-related tendency for a increase in MUAP amplitudes in slow MUs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. The effect of a high- intensity running (12weeks with bee pollen on gastrocnemius muscle ABCA1 and apoA1 mRNA expression in male rats

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    2016-10-01

    Full Text Available Abstract Background & Aims: The purpose of the current study was to investigate the effect of a high- intensity running (12weeks with bee pollen on gastrocnemius muscle ABCA1 and apoA1 mRNA expression in male rats. Materials & Methods: Twenty_ four Wistar male rats (4-6 weeks old, 90-110 g weight were used. Animals were randomly assigned into saline-control (SC, n=6, saline-training (ST, n=6, bee pollen- Control (BPC, n=6, and bee pollen-training (BPT, n=6 groups. Training groups have performed a high-intensity running program (30 m/min on 0% grade, 90min/day and 5 days/week on a motor-driven treadmill for 12 weeks. Animals were orally fed with bee pollen extraction (500 mg/kg body weight and saline solution for last 12 weeks. Rats were sacrificed 48 h after the last exercise session. A portion of gastrocnemius muscle were excised, cleaned and immediately frozen in liquid nitrogen and stored at -80 ° C until RNA extraction. Statistical analysis was performed using a two way ANOVA, and significance was accepted at P < 0.05. Results: A significant differences have found in gastrocnemius muscle ABCA1 gene expression between SC and BPC groups (P<0.000, ST with BPC groups (P< 0.000, ST with BPT groups (P< 0.040 and BPC with BPT groups (P< 0.000. Conclusion: The current results show that high-intensity running affected gastrocnemius muscle ABCA1 mRNA expression in different directions in saline (decrease and BPT (increase treated animals. Findings also indicate bee pollen consumption increase gastrocnemius muscle ABCA1 mRNA expression in rat.  Also apoA1 was not expressed in the gastrocnemius muscle of rat. Keywords: ABCA1, apoA1, Bee pollen, high- intensity running

  16. Diagnosis and Follow-up US Evaluation of Ruptures of the Medial Head of the Gastrocnemius

    International Nuclear Information System (INIS)

    Kwak, Hyo-Sung; Han, Young-Min; Lee, Sang-Yong; Kim, Ki-Nam; Chung, Gyung Ho

    2006-01-01

    The purpose of this study was to demonstrate the ultrasonographic (US) findings of rupture and the healing process of the medial head of the gastrocnemius ('Tennis Leg'). Twenty-two patients (age range: 30 to 45 years) with clinically suspected ruptures of the medial head of the gastrocnemius were referred to us for US examination. All the patients underwent US of the affected limb and the contralateral asymptomatic limb. Follow-up clinical evaluation and US imaging of all patients were performed at two-week intervals during the month after injury and at one-month intervals during the following six months. Of the 22 patients who had an initial US examination after their injury, partial rupture of the medial head of the gastrocnemius muscle was identified in seven patients (31.8%); the remaining 15 patients were diagnosed with complete rupture. Fluid collection between the medial head of the gastrocnemius and the soleus muscle was identified in 20 patients (90.9%). The thickness of the fluid collection, including the hematoma in the patients with complete rupture (mean: 9.7 mm), was significantly greater than that seen in the patients with partial tear (mean: 6.8 mm) (p < 0.01). The primary union of the medial head of the gastrocnemius with the soleus muscle in all the patients with muscle rupture and fluid collection was recognized via the hypoechoic tissue after four weeks. Ultrasonography is a useful imaging modality for the diagnosis and follow-up examination for the patients suffering with rupture of the medial head of the gastrocnemius

  17. Differential diagnosis of isolated calf muscle vein thrombosis and gastrocnemius hematoma by high-frequency ultrasound.

    Science.gov (United States)

    Su, Li-ya; Guo, Fa-jin; Xu, Guang; Han, Xiu-jie; Sun, Chang-kun; Zhang, Zheng; Jing, Qing-hong

    2013-12-01

    Differential diagnosis of isolated calf muscle vein thrombosis (ICMVT) and gastrocnemius hematoma is essential for early identification of deep vein thrombosis (DVT). This study aimed to investigate the diagnostic value of high-frequency color Doppler ultrasound for differential diagnosis of ICMVT and gastrocnemius hematoma. A retrospective case series of 35 ICMVT (M:F, 21:14; mean age (64.5 ± 10.6) years) and 23 gastrocnemius hematoma (M:F, 16:7; mean age (75.4 ± 11.8) years) patients with bilateral/unilateral lower limb pain was conducted between January 2006 and September 2012. Characteristics and the morphology of high-frequency color Doppler ultrasonography of the lower limb deep vein, great saphenous vein, calf muscles, skin, and soft tissue were examined. ICMVT hypoechoic signals were characterized by long, tube-like masses on longitudinal sections and oval masses on transverse sections, with apparent muscle thrombosis boundaries, distal and proximal venous connections, and, often, lower limb DVT. Gastrocnemius hematoma hypoechoic signals were characterized by large volumes, enhanced posterior hematoma echo, hyperechoic muscle boundaries, no hematoma blood flow, and no DVT, and clear differences in trauma/exercise- and oral anticoagulant-induced hematomas were readily apparent. According to the measurement, the ratio of long diameter/transverse diameter (D/T) in ICMVT patients was about less than 2.0, whereas in gastrocnemius hematoma patients the ratio was more than 2.0. Early stage isoechoic and hypoechoic signals were detected with gradually increasing ovular anechoic areas. Partial muscle fibers in the hematoma due to muscle fractures were apparent. High-frequency color Doppler ultrasound was found to be a sensitive and reliable method for differential diagnosis of ICMVT and gastrocnemius hematoma due to trauma and exercise or prolonged oral anticoagulant use.

  18. Diagnosis and Follow-up US Evaluation of Ruptures of the Medial Head of the Gastrocnemius

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Hyo-Sung; Han, Young-Min; Lee, Sang-Yong; Kim, Ki-Nam; Chung, Gyung Ho [Chonbuk National University Medical School, Chonju (Korea, Republic of)

    2006-09-15

    The purpose of this study was to demonstrate the ultrasonographic (US) findings of rupture and the healing process of the medial head of the gastrocnemius ('Tennis Leg'). Twenty-two patients (age range: 30 to 45 years) with clinically suspected ruptures of the medial head of the gastrocnemius were referred to us for US examination. All the patients underwent US of the affected limb and the contralateral asymptomatic limb. Follow-up clinical evaluation and US imaging of all patients were performed at two-week intervals during the month after injury and at one-month intervals during the following six months. Of the 22 patients who had an initial US examination after their injury, partial rupture of the medial head of the gastrocnemius muscle was identified in seven patients (31.8%); the remaining 15 patients were diagnosed with complete rupture. Fluid collection between the medial head of the gastrocnemius and the soleus muscle was identified in 20 patients (90.9%). The thickness of the fluid collection, including the hematoma in the patients with complete rupture (mean: 9.7 mm), was significantly greater than that seen in the patients with partial tear (mean: 6.8 mm) (p < 0.01). The primary union of the medial head of the gastrocnemius with the soleus muscle in all the patients with muscle rupture and fluid collection was recognized via the hypoechoic tissue after four weeks. Ultrasonography is a useful imaging modality for the diagnosis and follow-up examination for the patients suffering with rupture of the medial head of the gastrocnemius.

  19. Effect of Bisphenol-A (BPA) on insulin signal transduction and GLUT4 translocation in gastrocnemius muscle of adult male albino rat.

    Science.gov (United States)

    Mullainadhan, Vigneswari; Viswanathan, Mangala Priya; Karundevi, Balasubramanian

    2017-09-01

    Environmental estrogens bind to estrogen receptors, mimic estrogenic actions, and have adverse effects on human health like Bisphenol - A (BPA) which is used as a monomer in the production of polycarbonate plastics (PC) and epoxy resins which are used in variety of canned foods. Skeletal muscle plays an essential role in maintaining systemic glucose metabolism. In the present study, we investigated the possible effects of BPA on insulin signalling molecules and GLUT4 translocation in the gastrocnemius muscle of adult male rat. Rats were divided into four groups - Group I: Control (vehicle-corn oil treated), Group II, III and IV were administered with BPA (10, 100 and 400mg/kg b.wt/day, respectively) through oral gavage. Fasting blood glucose level of BPA treated groups showed a significant increase, oral glucose tolerance and insulin tolerance were also impaired in these animals. BPA significantly decreased the protein levels of insulin signalling molecules like IR, IRS-1, Akt, AS160 and its phosphorylated forms and blunts GLUT4 translocation by altering the levels of v- and t- SNARE proteins that assist the translocation process, thereby decreasing glucose uptake and oxidation in the gastrocnemius muscle. These results suggest that BPA has detrimental effects on insulin signalling molecules and GLUT4 translocation in the gastrocnemius muscle and thus impairs glucose homeostasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Reduced Radial Displacement of the Gastrocnemius Medialis Muscle After Electrically Elicited Fatigue.

    Science.gov (United States)

    Macgregor, Lewis J; Ditroilo, Massimiliano; Smith, Iain J; Fairweather, Malcolm M; Hunter, Angus M

    2016-08-01

    Assessments of skeletal-muscle functional capacity often necessitate maximal contractile effort, which exacerbates muscle fatigue or injury. Tensiomyography (TMG) has been investigated as a means to assess muscle contractile function after fatigue; however, observations have not been contextualized by concurrent physiological measures. To measure peripheral-fatigue-induced alterations in mechanical and contractile properties of the plantar-flexor muscles through noninvasive TMG concurrently with maximal voluntary contraction (MVC) and passive muscle tension (PMT) to validate TMG as a gauge of peripheral fatigue. Pre- and posttest intervention with control. University laboratory. 21 healthy male volunteers. Subjects' plantar flexors were tested for TMG parameters, along with MVC and PMT, before and after either a 5-min rest period (control) or a 5-min electrical-stimulation intervention (fatigue). Temporal (contraction velocity) and spatial (radial displacement) contractile parameters of the gastrocnemius medialis were recorded through TMG. MVC was measured as an indicator of muscle fatigue, and PMT was measured to assess muscle stiffness. Radial displacement demonstrated a fatigue-associated reduction (3.3 ± 1.2 vs 4.0 ± 1.4 mm, P = .031), while contraction velocity remained unaltered. In addition, MVC significantly declined by 122.6 ± 104 N (P fatigue). PMT was significantly increased after fatigue (139.8 ± 54.3 vs 111.3 ± 44.6 N, P = .007). TMG successfully detected fatigue, evident from reduced MVC, by displaying impaired muscle displacement accompanied by elevated PMT. TMG could be useful in establishing skeletal-muscle fatigue status without exacerbating the functional decrement of the muscle.

  1. Glycogen synthesis in human gastrocnemius muscle is not representative of whole-body muscle glycogen synthesis

    NARCIS (Netherlands)

    Serlie, Mireille J. M.; de Haan, Jacco H.; Tack, Cees J.; Verberne, Hein J.; Ackermans, Mariette T.; Heerschap, Arend; Sauerwein, Hans P.

    2005-01-01

    The introduction of C-13 magnetic resonance spectroscopy (MRS) has enabled noninvasive measurement of muscle glycogen synthesis in humans. Conclusions based on measurements by the MRS technique assume that glucose metabolism in gastrocnemius muscle is representative for all skeletal muscles and thus

  2. Glycogen synthesis in human gastrocnemius muscle is not representative of whole-body muscle glycogen synthesis.

    NARCIS (Netherlands)

    Serlie, M.J.; Haan, J.H.A. de; Tack, C.J.J.; Verberne, H.J.; Ackermans, M.T.; Heerschap, A.; Sauerwein, H.P.

    2005-01-01

    The introduction of 13C magnetic resonance spectroscopy (MRS) has enabled noninvasive measurement of muscle glycogen synthesis in humans. Conclusions based on measurements by the MRS technique assume that glucose metabolism in gastrocnemius muscle is representative for all skeletal muscles and thus

  3. Decreased gastrocnemius temporal muscle activation during gait in elderly women with history of recurrent falls.

    Science.gov (United States)

    Kirkwood, Renata Noce; Trede, Renato Guilherme; Moreira, Bruno de Souza; Kirkwood, Scott Alexander; Pereira, Leani Souza Máximo

    2011-05-01

    Gait dysfunction is a strong issue in elderly women with a history of falls. The purpose of this study was to compare the temporal activity of the ankle muscles during gait in elderly women with and without a history of recurrent falls. Eighty-nine (89) elderly women - one group with a history of falls (45) and another group without (44) - participated in the study. The mean range of temporal activation of the gastrocnemius, tibialis anterior and soleus muscles during gait was obtained using electromyography. The muscles were considered active when the signal magnitude surpassed two standard deviations of the minimal magnitude of the average signal per individual. The results showed that the mean range of gastrocnemius muscle activation of the group of recurrent fallers was significantly shorter, 2.9% (16.9±5.7%) compared to the group without recurrent falls (19.8±6.6%) (p=0.004). The shorter duration in the gastrocnemius muscle activation during stance could possibly affect stability in the support phase, since the gastrocnemius is the main decelerator of the trunk. Clinically, this finding shows the importance of rehabilitation programs for elderly women that focus on strengthening the plantar flexor musculature aiming to reestablish the function and stability of gait and possibly avoiding falls. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Tracking errors in tractography of the gastrocnemius muscle. A comparison between the transverse and sagittal planes

    International Nuclear Information System (INIS)

    Aoki, Takako; Tohdoh, Yukihiro; Tawara, Noriyuki; Okuwaki, Toru; Horiuchi, Akira; Itagaki, Takuma; Niitsu, Mamoru

    2010-01-01

    In scans taken in conventional direction, tracking errors may occur when using a streamline-based algorithm for the tractography of the gastrocnemius muscle. To solve errors in tracking, we applied tractography to the musculotendinous junction and performed fiber tracking on the gastrocnemius muscle of 10 healthy subjects with their written informed consent. We employed a spin-echo diffusion tensor imaging (SE-DTI) sequence with 6-direction diffusion gradient sensitization and acquired DTI images at 1.5 tesla using a body array coil with parallel imaging. We compared tractography obtained in the transverse and sagittal planes using anatomical reference and found that the gastrocnemius muscle and musculotendinous junction were significantly better visualized on sagittal scans and in 3 regions of interest. We utilized Mann-Whitney U-test to determine significant differences between rates of concordance (P 2 value of skeletal muscle is around 50 ms, and TE should be as short as possible. A streamline-based algorithm is based on the continuity of a vector. It is easy to take running of the muscle fiber in sagittal scan. Therefore, tracking error is hard to occur. In conclusion, sagittal scanning may be one way to eliminate tracking errors in the tractography of the gastrocnemius muscle. Tracking errors were smaller with sagittal scans than transverse scans, and sagittal scans allow better fiber tracking. (author)

  5. Effects of gastrocnemius recession on ankle motion, strength, and functional outcomes: a systematic review and national healthcare database analysis.

    Science.gov (United States)

    Gianakos, Arianna; Yasui, Youichi; Murawski, Christopher D; Kennedy, John G

    2016-04-01

    The purpose of this systematic review was to report the effects of gastrocnemius recession on ankle dorsiflexion range of motion, function, and push-off power. The MEDLINE and EMBASE databases were reviewed with terms "gastrocnemius recession". The inclusion criteria were: (1) clinical studies, (2) published in a peer-reviewed journal within the past 10 years, and (3) published in English. Excluded were: (1) review articles, (2) cadaveric studies, (3) studies including patients under the age of 18 years, (4) studies evaluating a neurologic condition, (5) level of evidence 5, and (6) Quality of Evidence Score trends. The PearlDiver Database was also used to review de-identified patient information retrospectively between 2007 and 2011. Full-text review yielded 23 articles that fit the inclusion criteria. Twenty-one of 23 (91%) and 2/23 (9%) studies were level of evidence 4 and 3, respectively. Twelve of 23 (52%) studies reported follow-up assessment between 12 and 36 months, and no studies reported longer-term follow-up. Twelve of 12 (100%) studies reported improved dorsiflexion range of motion 9/9 (100%) reported improved AOFAS, and 11/11 (100%) reported improved VAS. Five of 23 (22%) studies reported strength in a measured and controlled fashion with variable results, but of these, no study reported a return to normal power. The mean complication rate was 14%. The available evidence supports that GR improves functional outcomes and increases dorsiflexion range of motion. Furthermore, GR affects gait kinematics, which may cause compensatory effects at the knee, ankle, and subtalar joints. Evidence has shown that power does not return to normal levels. Clinicians may utilize these data clinically to determine whether patients may benefit from GR or not. IV.

  6. Acute effect of oral sensation of sweetness on celiac artery blood flow and gastric myoelectrical activity in humans.

    Science.gov (United States)

    Eguchi, Kohei; Kashima, Hideaki; Yokota, Akiko; Miura, Kohei; Yamaoka Endo, Masako; Hirano, Harutoyo; Tsuji, Toshio; Fukuba, Yoshiyuki

    2016-05-01

    Little is known about the effect of sweet taste stimulus on gastrointestinal motility and splanchnic blood flow. We examined whether gastric myoelectrical activity and/or celiac artery blood flow (CABF), which perfuses the stomach, are increased following an oral sensation of sweetness. After overnight fasting, 11 subjects rested for 5min and sipped, but not swallowed, one of four solutions for 1min. The fluid was then spat out, and subjects remained at rest for a further 10min. Fluids were approximately 15ml of three glucose solutions (4, 16, or 48%) or distilled water. Subjects completed trials with all four solutions in a randomized order. During each trial, gastric myoelectrical activity and CABF were continuously measured using electrogastrography and pulsed Doppler ultrasonography, respectively. None of the four solutions affected gastric myoelectrical activity. CABF was significantly increased after oral stimuli by all three glucose solutions, but not by water. There were no significant differences in the increments in CABF among the three glucose solutions. These results suggest that a sweet taste stimulus above a certain level of intensity acutely increases CABF during cephalic phase, without augmentation of gastric myoelectrical activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Effect of feeding on myoelectric activity of the sphincter of Oddi and the gastrointestinal tract in the opossum

    NARCIS (Netherlands)

    Coelho, J. C.; Gouma, D. J.; Moody, F. G.; Schlegel, J. F.

    1986-01-01

    The effect of different foods on the myoelectric activity of the sphincter of Oddi and gastrointestinal tract was evaluated in the opossum. Gallbladder pressure was also recorded. Feeding fat and mixed food resulted in the greatest incidence of spike activity in the duodenum and jejunum, followed by

  8. Intermanual Transfer in Training With an Upper-Limb Myoelectric Prosthesis Simulator : A Mechanistic, Randomized, Pretest-Posttest Study

    NARCIS (Netherlands)

    Romkema, Sietske; Bongers, Raoul M.; van der Sluis, Corry K.

    Background. Intermanual transfer may improve prosthetic handling and acceptance if used in training soon after an amputation. Objective. The purpose of this study was to determine whether intermanual transfer effects can be detected after training with a myoelectric upper-limb prosthesis simulator.

  9. Myoelectric Pattern Identification of Stroke Survivors Using Multivariate Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Xu Zhang

    2014-01-01

    Full Text Available This study presents a novel feature extraction method for myoelectric pattern recognition using a multivariate extension of empirical mode decomposition (EMD, namely multivariate EMD (MEMD. The method processes multiple surface electromyogram (EMG channels simultaneously rather than in a channel-by-channel manner. From mode-aligned intrinsic mode functions (IMFs, representing signal components over multiple scales derived from the MEMD analysis, normalized amplitude distributions of the same-mode/scale IMFs across different channels were calculated as features, which serve to reveal the underlying relationship in the aligned intrinsic scales across multiple muscles. The proposed method was assessed for identification of 18 different functional movement patterns via 27-channel surface EMG signals recorded from the paretic forearm muscles of 12 subjects with hemiparetic stroke. With a linear discriminant classifier, the proposed MEMD based feature set resulted in an average error rate of 4.61 ± 4.70% for classification of all the different movements, significantly lower than that of the conventional time-domain feature set (7.14 ± 6.15%, p < 0.05. The results indicate that the MEMD based feature extraction of multi-channel surface EMG data provides a promising approach to modeling of muscle couplings and identification of different myoelectric patterns.

  10. Giving Them a Hand: Wearing a Myoelectric Elbow-Wrist-Hand Orthosis Reduces Upper Extremity Impairment in Chronic Stroke.

    Science.gov (United States)

    Peters, Heather T; Page, Stephen J; Persch, Andrew

    2017-09-01

    To determine the immediate effect of a portable, myoelectric elbow-wrist-hand orthosis on paretic upper extremity (UE) impairment in chronic, stable, moderately impaired stroke survivors. Observational cohort study. Outpatient rehabilitation clinic. Participants exhibiting chronic, moderate, stable, poststroke, UE hemiparesis (N=18). Subjects were administered a battery of measures testing UE impairment and function. They then donned a fabricated myoelectric elbow-wrist-hand orthosis and were again tested on the same battery of measures while wearing the device. The primary outcome measure was the UE Section of the Fugl-Meyer Scale. Subjects were also administered a battery of functional tasks and the Box and Block (BB) test. Subjects exhibited significantly reduced UE impairment while wearing the myoelectric elbow-wrist-hand orthosis (FM: t 17 =8.56, Phand orthosis, with 3 subtasks showing significant increases (feeding [grasp]: z=2.251, P=.024; feeding [elbow]: z=2.966, P=.003; drinking [grasp]: z=3.187, P=.001). Additionally, subjects showed significant decreases in time taken to grasp a cup (z=1.286, P=.016) and increased gross manual dexterity while wearing a myoelectric elbow-wrist-hand orthosis (BB test: z=3.42, Phand orthosis, and these changes exceeded the Fugl-Meyer Scale's clinically important difference threshold. Further, utilization of a myoelectric elbow-wrist-hand orthosis significantly increased gross manual dexterity and performance of certain functional tasks. Future work will integrate education sessions to increase subjects' ability to perform multijoint functional movements and attain consistent functional changes. Copyright © 2017. Published by Elsevier Inc.

  11. Concomitant Contracture of the Knee and Ankle Joint After Gastrocnemius Muscle Rupture: A Case Report.

    Science.gov (United States)

    Ryu, Dong Jin; Kim, Joon Mee; Kim, Bom Soo

    Injury of the medial head of the gastrocnemius, also called "tennis leg," is known to heal uneventfully in most cases with compression and immobilization therapy. Failure to heal or long-term complications, including ongoing pain and pes equinus, have been documented in only a limited number of case reports. To the best of our knowledge, a severe concomitant contracture of the knee and ankle joint as a consequence of a maltreated gastrocnemius muscle rupture has not been previously reported in English-language reports. The purpose of the present study was to report a serious complication of neglected tennis leg with a review of the published data. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Gastrocnemius tendon strain in a dog treated with autologous mesenchymal stem cells and a custom orthosis.

    Science.gov (United States)

    Case, J Brad; Palmer, Ross; Valdes-Martinez, Alex; Egger, Erick L; Haussler, Kevin K

    2013-05-01

    To report clinical findings and outcome in a dog with gastrocnemius tendon strain treated with autologous mesenchymal stem cells and a custom orthosis. Clinical report. A 4-year-old spayed female Border Collie. Bone-marrow derived, autologous mesenchymal stem cells were transplanted into the tendon core lesion. A custom, progressive, dynamic orthosis was fit to the tarsus. Serial orthopedic examinations and ultrasonography as well as long-term force-plate gait analysis were utilized for follow up. Lameness subjectively resolved and peak vertical force increased from 43% to 92% of the contralateral pelvic limb. Serial ultrasonographic examinations revealed improved but incomplete restoration of normal linear fiber pattern of the gastrocnemius tendon. Findings suggest that autologous mesenchymal stem cell transplantation with custom, progressive, dynamic orthosis may be a viable, minimally invasive technique for treatment of calcaneal tendon injuries in dogs. © Copyright 2013 by The American College of Veterinary Surgeons.

  13. [Musculotendinopathy of the gastrocnemius muscle in a Labrador Retriever. A case report].

    Science.gov (United States)

    Fiedler, A M; Amort, K H; Bokemeyer, J; Kramer, M

    2013-01-01

    Musculotendinopathy at the origin of the gastrocnemius muscle is a rare disease mostly described in herding dogs. The etiology is based on repeated myotendinous strain of the muscle in athletic dogs. Clinically, the patient displays chronic pelvic limb lameness and pain at the lateral fabella during palpation of this area. There is no instability of the stifle present. Radiographic findings (osteophyte formation at the origin of the muscle and the lateral fabella) support the potential diagnosis. Magnetic resonance tomography shows edematous changes and enhancement after intravenous application of contrast agent in the area of the origin of the lateral gastrocnemius head. With conservative treatment (i. e. leash confinement, NSAID application and physiotherapy) the prognosis is good. This case report describes clinical findings, diagnostic imaging, therapy and long-term outcome of an athletic Labrador Retriever presented with this disease.

  14. Glycogen accumulation in normal and irradiated minced muscle autografts on frog gastrocnemius

    International Nuclear Information System (INIS)

    Malhotra, R.K.; Kaul, R.; Malhotra, N.

    1989-01-01

    Alterations induced in glycogen content and phosphorylase activity have been studied in normal and irradiated minced muscle autografts on frog gastrocnemius at days 1, 3, 5, 7, 10, 15 and 30 postgrafting. The changes observed in the glycogen content and phosphorylase activity conform to the degeneration and regeneration phases of muscle repair. An attempt has been made to explain the altered glycogen utilizing capacities of the frog skeletal muscle during its repair and regeneration. (author)

  15. Gastrocnemius mitochondrial respiration: are there any differences between men and women?

    Science.gov (United States)

    Thompson, Jonathan R; Swanson, Stanley A; Casale, George P; Johanning, Jason M; Papoutsi, Evlampia; Koutakis, Panagiotis; Miserlis, Dimitrios; Zhu, Zhen; Pipinos, Iraklis I

    2013-11-01

    Work on human and mouse skeletal muscle by our group and others has demonstrated that aging and age-related degenerative diseases are associated with mitochondrial dysfunction, which may be more prevalent in males. There have been, however, no studies that specifically examine the influence of male or female sex on human skeletal muscle mitochondrial respiration. The purpose of this study was to compare mitochondrial respiration in the gastrocnemius of adult men and women. Gastrocnemius muscle was obtained from male (n = 19) and female (n = 11) human subjects with healthy lower-extremity musculoskeletal and arterial systems and normal ambulatory function. All patients were undergoing operations for the treatment of varicose veins in their legs. Mitochondrial respiration was determined with a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles. Complex I-, II-, III-, and IV-dependent respiration was measured individually and normalized to muscle weight, total protein content, and citrate synthase (CS, index of mitochondrial content). Male and female patients had no evidence of musculoskeletal or arterial disease and did not differ with regard to age, race, body mass index, or other clinical characteristics. Complex I-, II-, III-, and IV-dependent respiration normalized to muscle weight, total protein content, and CS did not statistically differ for males compared with females. Our study evaluates, for the first time, gastrocnemius mitochondrial respiration of adult men and women who have healthy musculoskeletal and arterial systems and normal ambulatory function. Our data demonstrate there are no differences in the respiration of gastrocnemius mitochondria between men and women. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Anatomical aspects of the gastrocnemius muscles: A study in 47 fresh cadavers.

    Science.gov (United States)

    Andjelkov, Katarina; Atanasijevic, Tatjana C; Popovic, Vesna M; Sforza, Marcos; Atkinson, Connor J; Soldatovic, Ivan

    2016-08-01

    This study offers objective dimensions of the gastrocnemius muscle and analyzes correlations between dimensional variables, with a view to providing guidance on the proportions of a healthy gastrocnemius muscle for both genders. This anatomical study was conducted at the Institute of Forensic Medicine Faculty of Medicine University of Belgrade, Serbia, from May until November 2014. We included 47 fresh cadavers (up to 12-h postmortem interval) both male and female. The inclusion criteria were absence of any trauma or degenerative findings in lower limbs, normally weighed, and age between 18 and 60 years. The exclusion criteria were significant difference in dimensions between legs and overweighed cadavers. After statistical analysis of gathered data, we were able to define the exact shape and average measures of the medial and lateral head of gastrocnemius muscle in male and female. Factors affecting muscle dimensions are also defined in this study. The method of dissection that we applied could be recommended for exploration of different anatomical structures of calf region. The reported dimensions and correlations are useful guide in planning cosmetic and reconstructive procedures with high accuracy. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Blood flow distribution in dog gastrocnemius muscle at rest and during stimulation

    International Nuclear Information System (INIS)

    Piiper, J.; Pendergast, D.R.; Marconi, C.; Meyer, M.; Heisler, N.; Cerretelli, P.

    1985-01-01

    The distribution of blood flow within the isolated perfused dog gastrocnemius muscle (weight 100-240 g) was studied by intra-arterial injection of radioactively labeled microspheres (diameter 15 micron) at rest and during supramaximal stimulation to rhythmic isotonic tetanic contractions of varied frequency against varied loads. After the experiment the muscle was cut into 180-250 pieces of approximately 0.75 g each, and the blood flow to each muscle piece was determined from its radioactivity. The inhomogeneity of blood flow was represented as the frequency distribution of the ratios of regional specific blood flow, i.e., blood flow per unit tissue weight of the piece, QR, to the overall specific blood flow of the muscle, Q. The QR/Q values for the individual pieces of a muscle were found to vary widely both at rest and during stimulation. With rising work load the frequency distribution had a tendency to broaden and flatten, indicating increasing perfusion inhomogeneity. On the average of the experiments, there was no significant difference in specific blood flow between the three anatomic components of the gastrocnemius (lateral and medial heads of gastrocnemius and flexor digitorum superficialis) nor between the superficial and deep portions within these anatomic components, only the distal third of the muscle was relatively less perfused compared with the proximal two-thirds. The considerable inhomogeneity of blood flow as revealed by microsphere embolization and by other methods is expected to exert important limiting effects on local O 2 supply, particularly during exercise

  18. Postprandial symptoms in dysmotility-like functional dyspepsia are not related to disturbances of gastric myoelectrical activity

    Directory of Open Access Journals (Sweden)

    A.S. Oba-Kuniyoshi

    2004-01-01

    Full Text Available Gastric dysrhythmias, such as tachy- or bradygastria, have been reported in patients with functional dyspepsia (FD, but their role in symptom production is uncertain. It is also not known whether gastric dysrhythmias in these patients can be elicited by physiological gastric distension with a meal. We investigated the relationships between symptoms after ingestion of different volumes of water following a test meal and gastric dysrhythmias in FD patients. Fourteen patients with dysmotility-like FD and 13 healthy volunteers underwent paired electrogastrography (EGG studies. Fasted subjects ingested 150 ml of yoghurt with either 150 ml (low volume or 300 ml (high volume water in random order. Fasting and fed EGGs with monitoring of symptoms were performed in both studies. Ten FD patients (71.4% reported upper abdominal discomfort and bloating after the low volume meal, but only one (7.1% presented an abnormal EGG (dominant frequency in the 2-4-cpm range: 58%. Following the high volume meal, 7 patients (50% had symptoms, but none had EGG abnormalities. No significant differences were found between FD patients and controls for any of the EGG variables, in any test. In FD patients with postprandial symptoms, the percentage of the EGG dominant frequency in the normal range (median, 84.6%; range, 76.0-100.0% was similar (P > 0.20 to that in those without symptoms (88.5%; 75.0-100.0%. We conclude that disturbances of gastric myoelectrical activity are unlikely to play a role in the origin of postprandial upper abdominal discomfort and bloating in dysmotility-like FD.

  19. Popliteal vascular entrapment syndrome caused by a rare anomalous slip of the lateral head of the gastrocnemius muscle

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Patrick T.; Moyer, Adrian C.; Huettl, Eric A. [Mayo Clinic Scottsdale, Department of Radiology, Scottsdale (United States); Fowl, Richard J.; Stone, William M. [Mayo Clinic Scottsdale, Department of Vascular Surgery, Scottsdale (United States)

    2005-06-01

    Popliteal vascular entrapment syndrome can result in calf claudication, aneurysm formation, distal arterial emboli, or popliteal vessel thrombosis. The most commonly reported causes of this syndrome have been anomalies of the medial head of the gastrocnemius muscle as it relates to the course of the popliteal artery. We report two cases of rare anomalous slips of the lateral head of the gastrocnemius muscle causing popliteal vascular entrapment syndrome. (orig.)

  20. sEMG Sensor Using Polypyrrole-Coated Nonwoven Fabric Sheet for Practical Control of Prosthetic Hand.

    Science.gov (United States)

    Jiang, Yinlai; Togane, Masami; Lu, Baoliang; Yokoi, Hiroshi

    2017-01-01

    One of the greatest challenges of using a myoelectric prosthetic hand in daily life is to conveniently measure stable myoelectric signals. This study proposes a novel surface electromyography (sEMG) sensor using polypyrrole-coated nonwoven fabric sheet as electrodes (PPy electrodes) to allow people with disabilities to control prosthetic limbs. The PPy electrodes are sewn on an elastic band to guarantee close contact with the skin and thus reduce the contact electrical impedance between the electrodes and the skin. The sensor is highly customizable to fit the size and the shape of the stump so that people with disabilities can attach the sensor by themselves. The performance of the proposed sensor was investigated experimentally by comparing measurements of Ag/AgCl electrodes with electrolytic gel and the sEMG from the same muscle fibers. The high correlation coefficient (0.87) between the two types of sensors suggests the effectiveness of the proposed sensor. Another experiment of sEMG pattern recognition to control myoelectric prosthetic hands showed that the PPy electrodes are as effective as Ag/AgCl electrodes for measuring sEMG signals for practical myoelectric control. We also investigated the relation between the myoelectric signals' signal-to-noise ratio and the source impedances by simultaneously measuring the source impedances and the myoelectric signals with a switching circuit. The results showed that differences in both the norm and the phase of the source impedance greatly affect the common mode noise in the signal.

  1. Task discrimination from myoelectric activity: a learning scheme for EMG-based interfaces.

    Science.gov (United States)

    Liarokapis, Minas V; Artemiadis, Panagiotis K; Kyriakopoulos, Kostas J

    2013-06-01

    A learning scheme based on Random Forests is used to discriminate the task to be executed using only myoelectric activity from the upper limb. Three different task features can be discriminated: subspace to move towards, object to be grasped and task to be executed (with the object). The discrimination between the different reach to grasp movements is accomplished with a random forests classifier, which is able to perform efficient features selection, helping us to reduce the number of EMG channels required for task discrimination. The proposed scheme can take advantage of both a classifier and a regressor that cooperate advantageously to split the task space, providing better estimation accuracy with task-specific EMG-based motion decoding models, as reported in [1] and [2]. The whole learning scheme can be used by a series of EMG-based interfaces, that can be found in rehabilitation cases and neural prostheses.

  2. Relationship of Sphincter of Oddi Spike Bursts to Gastrointestinal Myoelectric Activity in Conscious Opossums

    Science.gov (United States)

    Honda, Ryuichi; Toouli, James; Dodds, Wylie J.; Sarna, Sushil; Hogan, Walter J.; Itoh, Zen

    1982-01-01

    The oppossum sphincter of Oddi (SO) exhibits peristaltic spike bursts with accompanying contraction waves that originate proximally in the sphincter of Oddi and propagate toward the duodenum. In this study we recorded myoelectrical activity of the opossum SO and upper gastrointestinal tract in six conscious animals using chronically implanted electrodes. Biopolar electrodes were implanted in the gastric antrum, duodenum, SO segment, jejunum, and ileum. During fasting the frequency of SO spike bursts, scored as number per minute, showed a cyclic pattern consisting of four phases (A to D). Phase A had a low spike burst frequency of ∼2/min that lasted ∼20 min. In phase B, the spike burst frequency increased progressively during a 40-45 min interval culminating in a short interval of phase C activity characterized by a maximal spike burst frequency of ∼5/min. During phase D, the spike bursts decreased over 15 min to merge with the low frequency of phase A and the cycle repeated. Cycle length of the interdigestive SO cycle, 87±11 SD min, was virtually identical with that of the interdigestive migrating myoelectric complex (MMC) of the upper gastrointestinal tract. The onset of phase C activity in the SO began 1-2 min before phase III of the MMC activity in the duodenum. Feeding abolished the cyclic pattern of spike burst activity in the SO as well as in the upper gastrointestinal tract. After feeding the SO spike bursts occurred at a frequency of 5-6/min for at least 3 h. We conclude that: (a) During fasting, the oppossum SO exhibits cyclic changes in its spike burst frequency; (b) Maximal spike burst frequency of the SO occurs virtually concurrent with passage of phase III MMC activity through the duodenum and; (c) Feeding abolishes the interdigestive cyclic spike burst pattern of the SO as well as that of the gastrointestinal tract. PMID:7076847

  3. [Effect of Dry Needling Stimulation of Myofascial Trigger Point on Sample Entropy of Electromyography of Gastrocnemius Injured Site in Rats].

    Science.gov (United States)

    Ding, Chen-Li; Ma, Yan-Tao; Huang, Qiang-Min; Liu, Qing-Guang; Zhao, Jia-Min

    2018-02-25

    To attempt to establish an objective quantitative indicator to characterize the trigger point activity, so as to evaluate the effect of dry needling on myofascial trigger point activity. Twenty-four male Sprague-Dawley rats were randomly divided into blank control group, dry needling (needling) group, stretching exercise (stretching) group and needling plus stretching group ( n =6 per group). The chronic myofascial pain (trigger point) model was established by freedom vertical fall of a wooden striking device onto the mid-point of gastrocnemius belly of the left hind-limb to induce contusion, followed by forcing the rat to make a continuous downgrade running exercise at a speed of 16 m/min for 90 min on the next day which was conducted once a week for 8 weeks. Electromyography (EMG) of the regional myofascial injured point was monitored and recorded using an EMG recorder via electrodes. It was considered success of the model if spontaneous electrical activities appeared in the injured site. After a 4 weeks' recovery, rats of the needling group were treated by filiform needle stimulation (lifting-thrusting-rotating) of the central part of the injured gastrocnemius belly (about 10 mm deep) for 6 min, and those of the stretching group treated by holding the rat's limb to make the hip and knee joints to an angle of about 180°, and the ankle-joint about 90° for 1 min every time, 3 times altogether (with an interval of 1 min between every 2 times). The activity of the trigger point was estimated by the sample entropy of the EMG signal sequence in reference to Richman's and Moorman's methods to estimate the curative effect of both needling and exercise. After the modeling cycle, the mean sample entropies of EMG signals was significantly decreased in the model groups (needling group [0.034±0.010], stretching group [0.045±0.023], needling plus stretching group [0.047±0.034]) relevant to the blank control group (0.985±0.196, P 0.05), suggesting a better efficacy of

  4. Changes in Muscular Lipids in Unilateral Isolated Hypertrophy of Gastrocnemius Muscle Can Be Revealed by 1H MR Spectroscopy

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    Brechtel, Klaus; Machann, Juergen; Pick, Margarete; Schaefer, Juergen F.; Claussen, Claus D.; Schick, Fritz [University of Tuebingen, Tuebingen (Germany)

    2009-12-15

    To test whether proton magnetic resonance spectroscopy ({sup 1}H-MRS) reveals changes in the lipid content of the gastrocnemius muscle (GM) and soleus muscle (SOL) of a patient with unilateral isolated hypertrophy of the right GM. {sup 1}H-MRS was performed on a 1.5 Tesla (T) wholebody unit. Muscular lipids inside SOL and GM were assessed in both calves of the patient by a STEAM (stimulated echo acquisition mode) localization sequence. Results were compared to a control group of four healthy volunteers. Total amount of muscular lipids in the hypertrophic GM of the patient was clearly increased compared to the controls (38.7 versus 21.8{+-}3.5 a.u.) while intramyocellular lipids of the adjacent SOL were lower compared to the contralateral healthy leg. Muscular lipids are substrates for metabolism and can be assessed non-invasively by {sup 1}H-MRS. {sup 1}H-MRS is considered to be a helpful tool in clinical assessment of muscle metabolism in cases with muscular hypo- or hypertrophy.

  5. The Acute Effects of Static and Cyclic Stretching on Muscle Stiffness and Hardness of Medial Gastrocnemius Muscle.

    Science.gov (United States)

    Maeda, Noriaki; Urabe, Yukio; Tsutsumi, Shogo; Sakai, Shogo; Fujishita, Hironori; Kobayashi, Toshiki; Asaeda, Makoto; Hirata, Kazuhiko; Mikami, Yukio; Kimura, Hiroaki

    2017-12-01

    This study aimed to clarify the acute effects of static stretching (SS) and cyclic stretching (CS) on muscle stiffness and hardness of the medial gastrocnemius muscle (MG) by using ultrasonography, range of motion (ROM) of the ankle joint and ankle plantar flexor. Twenty healthy men participated in this study. Participants were randomly assigned to SS, CS and control conditions. Each session consisted of a standard 5-minute cycle warm-up, accompanied by one of the subsequent conditions in another day: (a) 2 minutes static stretching, (b) 2 minutes cyclic stretching, (c) control. Maximum ankle dorsiflexion range of motion (ROM max) and normalized peak torque (NPT) of ankle plantar flexor were measured in the pre- and post-stretching. To assess muscle stiffness, muscle-tendon junction (MTJ) displacement (the length changes in tendon and muscle) and MTJ angle (the angle made by the tendon of insertion and muscle fascicle) of MG were measured using ultrasonography at an ankle dorsiflexion angle of -10°, 0°, 10° and 20° before and after SS and CS for 2 minutes in the pre- and post-stretching. MG hardness was measured using ultrasound real-time tissue elastography (RTE). The results of this study indicate a significant effect of SS for ROM maximum, MTJ angle (0°, 10°, 20°) and RTE (10°, 20°) compared with CS (p muscle stiffness and hardness compared with CS. In addition, CS may contribute to the elongation of muscle tissue and increased muscle strength.

  6. Cerebral blood perfusion changes in amputees with myoelectric hands after rehabilitation: a SPECT computer-aided analysis.

    Science.gov (United States)

    Liu, Qiufang; Zheng, Xiujuan; Li, Panli; Xu, Lian; He, Longwen; Mei, Zhao; Zhu, Yinyan; Huang, Gang; Zhong, Chunlong; Song, Shaoli

    2016-08-31

    Rehabilitation, which is essential for amputees with myoelectric hands, can improve the quality of daily life by remodeling the neuron network. In our study, we aim to develop a cerebral blood perfusion (CBF) single-photon emission computed tomography computer-aided (SPECT-CA) detection scheme to automatically locate the brain's activated regions after rehabilitation. Five participants without forearms (three male, two female, mean age 51 ± 12.89 years, two missing the right side, and three missing the left side) were included in our study. In the clinical assessment, all of the participants received higher scores after training. The results of the SPM analysis indicated that CBF in the precentral gyrus, postcentral gyrus, frontal lobe, temporal lobe and cerebellum was significantly different among the five participants (P rehabilitation with high sensitivity and accuracy. This method has great potential for locating the remodeled neuron regions of amputees with myoelectric hands after rehabilitation.

  7. Myoelectric manifestation of muscle fatigue in repetitive work detected by means of miniaturized sEMG sensors.

    Science.gov (United States)

    Ranavolo, Alberto; Chini, Giorgia; Silvetti, Alessio; Mari, Silvia; Serrao, Mariano; Draicchio, Francesco

    2017-09-25

    Upper limb work-related musculoskeletal disorders have a 12-month prevalence ranging from 12 to 41% worldwide and can be partly caused by handling low loads at high frequency. The association between the myoelectric manifestation of elbow flexor muscle fatigue and occupational physical demand has never been investigated. It was hypothesized that an elbow flexor muscle fatigue index could be a valid risk indicator in handling low loads at high frequency. This study aims to measure the myoelectric manifestation of muscle fatigue of the three elbow flexor muscles during the execution of the work tasks in different risk conditions. Fifteen right-handed healthy adults were screened using a movement analysis laboratory consisting of optoelectronic, dynamometer and surface electromyographic systems. The main result indicates that the fatigue index calculated from the brachioradialis is sensitive to the interaction among risk classes, session and gender, and above all it is sensitive to the risk classes.

  8. Safety and Efficacy of Selective Neurectomy of the Gastrocnemius Muscle for Calf Reduction in 300 Cases.

    Science.gov (United States)

    Wang, Haibin; Xu, Xiang; Sun, Zhongsheng; Luo, Shengkang

    2015-10-01

    Liposuction alone is not always sufficient to correct the shape of the lower leg, and muscle reduction may be necessary. To assess the outcomes of a new technique of selective neurectomy of the gastrocnemius muscle to correct calf hypertrophy. Between October 2007 and May 2010, 300 patients underwent neurectomy of the medial and lateral heads of the gastrocnemius muscle at the Department of Cosmetic and Plastic Surgery, the Second People's Hospital of Guangdong Province (Guangzhou, China) to correct the shape of their lower legs. Follow-up data from these 300 patients were analyzed retrospectively. Cosmetic results were evaluated independently by the surgeon, the patient, and a third party. Preoperative and postoperative calf circumferences were compared. The Fugl-Meyer motor function assessment was evaluated 3 months after surgery. The average reduction in calf circumference was 3.2 ± 1.2 cm. The Fugl-Meyer scores were normal in all patients both before and 3 months after surgery. A normal calf shape was achieved in all patients. Six patients complained of fatigue while walking and four of scar pigmentation, but in all cases, this resolved within 6 months. Calf asymmetry was observed in only two patients. The present series suggests that neurectomy of the medial and lateral heads of the gastrocnemius muscle may be safe and effective for correcting the shape of the calves. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  9. TIME COURSE ALTERATIONS OF SATELLITE CELL EVENTS IN RESPONSE TO LIGHT MODERATE ENDURANCE TRAINING IN WHITE GASTROCNEMIUS MUSCLE OF THE RAT

    Directory of Open Access Journals (Sweden)

    Zong-Yan Cai

    2012-01-01

    Full Text Available This study investigated satellite cells and their related molecular events adapted to light moderate endurance training in the white gastrocnemius muscle of the rat. The white gastrocnemius muscle of male Sprague-Dawley rats that had been trained for 4 weeks and 8 weeks, with control rats being analysed alongside them, was selected for analysis (n=3 per group. The training protocol consisted of treadmill running at 20 m · min-1 for 30 min on a 0% grade, for 3 days · week-1. Immunohistochemical staining coupled with image analysis was used for quantification. To provide deeper insight into the cell layer, 40 sections per rat, corresponding to 120 values per group, were obtained as a mean value for statistical comparison. The results indicated that at week 4, training effects increased the vascular endothelial growth factor (VEGF content and c-met positive satellite cell numbers. At week 8, the training effect was attenuated for VEGF and c-met satellite cell numbers, but it increased in the muscle fibre area. Additionally, c-met positive satellite cell numbers correlated with VEGF content (r = 0.79, p<0.05. In conclusion, this study suggests that light moderate endurance training could stimulate satellite cell activation that might be related to VEGF signalling. Additionally, the satellite cells activated by moderate endurance training might contribute to slight growth in myocytes.

  10. Analysis of Differentially Expressed Genes in Gastrocnemius Muscle between DGAT1 Transgenic Mice and Wild-Type Mice

    Directory of Open Access Journals (Sweden)

    Fei Ying

    2017-01-01

    Full Text Available Adipose tissue was the major energy deposition site of the mammals and provided the energy for the body and released the external pressure to the internal organs. In animal production, fat deposition in muscle can affect the meat quality, especially the intramuscular fat (IMF content. Diacylglycerol acyltransferase-1 (DGAT1 was the key enzyme to control the synthesis of the triacylglycerol in adipose tissue. In order to better understand the regulation mechanism of the DGAT1 in the intramuscular fat deposition, the global gene expression profiling was performed in gastrocnemius muscle between DGAT1 transgenic mice and wild-type mice by microarray. 281 differentially expressed transcripts were identified with at least 1.5-fold change and the p value < 0.05. 169 transcripts were upregulated and 112 transcripts were downregulated. Ten genes (SREBF1, DUSP1, PLAGL1, FKBP5, ZBTB16, PPP1R3C, CDC14A, GLUL, PDK4, and UCP3 were selected to validate the reliability of the chip’s results by the real-time PCR. The finding of RT-PCR was consistent with the gene chip. Seventeen signal pathways were analyzed using KEGG pathway database and the pathways concentrated mainly on the G-protein coupled receptor protein signaling pathway, signal transduction, oxidation-reduction reaction, olfactory receptor activity, protein binding, and zinc ion binding. This study implied a function role of DGAT1 in the synthesis of TAG, insulin resistance, and IMF deposition.

  11. Effects of local fatigue on myoelectrical activity of erector spine muscles and the center for pressure displacement of the feet during balance recovery following postural perturbation in kyphotic subjects

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    Rooholah Rezaee

    2014-07-01

    Full Text Available Background: kyphosis deformity affects postural control. Muscular fatigue is one of the factors that can impair the mechanism of body balance. The aim of this study was to determine the effects of local fatigue on the myoelectrical activity of erector spine muscles and the center for pressure displacement of the feet during balance recovery following postural perturbation in kyphotic subjects. Methods: In this quasi-experimental study, 12 male students with>40 degrees thoracic kyphosis and 12 controls were selected to participate in the study. A flexible ruler was used to measure thoracic kyphosis. For postural control assessment, each subject underwent unexpected, forward-backward perturbations while standing on a foot scan mounted on a movable plate triggered by a weight equivalent to 10% of the subjects’ body weight. Experimental procedure was measured before (3 trails and after (3 trials the fatigue protocol. The myoelectric activity of the erector spine and multi fidus was compared in the groups using repeated measures of ANOVA and independent t-test (P<0.05. Results: There was no significant difference in the foot center of pressure displacement in both groups after muscular fatigue. After fatigue, there was an increase in the activity of longissimus thoracis (P=0.001 and iliocostalis thoracis (P= 0.001 in control group, while no significant difference was reported for the muscular activity of multifidus (p=0.084. The activity of langisimus thoracis was significantly increased (P=0.028 in kyphtic group after fatigue. Conclusion: erector spine muscles fatigue could not significantly affect the postural control in both groups, but the electrical activity of erector spine muscles during balance recovery following postural perturbation in kyphotic subjects was different than the controls.

  12. A Biomechanical Comparison of Proportional Electromyography Control to Biological Torque Control Using a Powered Hip Exoskeleton.

    Science.gov (United States)

    Young, Aaron J; Gannon, Hannah; Ferris, Daniel P

    2017-01-01

    Despite a large increase in robotic exoskeleton research, there are few studies that have examined human performance with different control strategies on the same exoskeleton device. Direct comparison studies are needed to determine how users respond to different types of control. The purpose of this study was to compare user performance using a robotic hip exoskeleton with two different controllers: a controller that targeted a biological hip torque profile and a proportional myoelectric controller. We tested both control approaches on 10 able-bodied subjects using a pneumatically powered hip exoskeleton. The state machine controller targeted a biological hip torque profile. The myoelectric controller used electromyography (EMG) of lower limb muscles to produce a proportional control signal for the hip exoskeleton. Each subject performed two 30-min exoskeleton walking trials (1.0 m/s) using each controller and a 10-min trial with the exoskeleton unpowered. During each trial, we measured subjects' metabolic cost of walking, lower limb EMG profiles, and joint kinematics and kinetics (torques and powers) using a force treadmill and motion capture. Compared to unassisted walking in the exoskeleton, myoelectric control significantly reduced metabolic cost by 13% ( p  = 0.005) and biological hip torque control reduced metabolic cost by 7% ( p  = 0.261). Subjects reduced muscle activity relative to the unpowered condition for a greater number of lower limb muscles using myoelectric control compared to the biological hip torque control. More subjects subjectively preferred the myoelectric controller to the biological hip torque control. Myoelectric control had more advantages (metabolic cost and muscle activity reduction) compared to a controller that targeted a biological torque profile for walking with a robotic hip exoskeleton. However, these results were obtained with a single exoskeleton device with specific control configurations while level walking at a

  13. A Biomechanical Comparison of Proportional Electromyography Control to Biological Torque Control Using a Powered Hip Exoskeleton

    Directory of Open Access Journals (Sweden)

    Aaron J. Young

    2017-06-01

    Full Text Available BackgroundDespite a large increase in robotic exoskeleton research, there are few studies that have examined human performance with different control strategies on the same exoskeleton device. Direct comparison studies are needed to determine how users respond to different types of control. The purpose of this study was to compare user performance using a robotic hip exoskeleton with two different controllers: a controller that targeted a biological hip torque profile and a proportional myoelectric controller.MethodsWe tested both control approaches on 10 able-bodied subjects using a pneumatically powered hip exoskeleton. The state machine controller targeted a biological hip torque profile. The myoelectric controller used electromyography (EMG of lower limb muscles to produce a proportional control signal for the hip exoskeleton. Each subject performed two 30-min exoskeleton walking trials (1.0 m/s using each controller and a 10-min trial with the exoskeleton unpowered. During each trial, we measured subjects’ metabolic cost of walking, lower limb EMG profiles, and joint kinematics and kinetics (torques and powers using a force treadmill and motion capture.ResultsCompared to unassisted walking in the exoskeleton, myoelectric control significantly reduced metabolic cost by 13% (p = 0.005 and biological hip torque control reduced metabolic cost by 7% (p = 0.261. Subjects reduced muscle activity relative to the unpowered condition for a greater number of lower limb muscles using myoelectric control compared to the biological hip torque control. More subjects subjectively preferred the myoelectric controller to the biological hip torque control.ConclusionMyoelectric control had more advantages (metabolic cost and muscle activity reduction compared to a controller that targeted a biological torque profile for walking with a robotic hip exoskeleton. However, these results were obtained with a single exoskeleton device with specific

  14. Biomechanic and Energetic Effects of a Quasi-Passive Artificial Gastrocnemius on Transtibial Amputee Gait

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    Michael F. Eilenberg

    2018-01-01

    Full Text Available State-of-the-art transtibial prostheses provide only ankle joint actuation and thus do not provide the biarticular function of the amputated gastrocnemius muscle. We develop a prosthesis that actuates both knee and ankle joints and then evaluate the incremental effects of this prosthesis as compared to ankle actuation alone. The prosthesis employs a quasi-passive clutched-spring knee orthosis, approximating the largely isometric behavior of the biological gastrocnemius, and utilizes a commercial powered ankle-foot prosthesis for ankle joint functionality. Two participants with unilateral transtibial amputation walk with this prosthesis on an instrumented treadmill, while motion, force, and metabolic data are collected. Data are analyzed to determine differences between the biarticular condition with the activation of the knee orthosis and the monoarticular condition with the orthosis behaving as a free-joint. As hypothesized, the biarticular system is shown to reduce both affected-side knee and hip moment impulse and positive mechanical work in both participants during the late stance knee flexion phase of walking, compared to the monoarticular condition. The metabolic cost of walking is also reduced for both participants. These very preliminary results suggest that biarticular functionality may provide benefits beyond even those of the most advanced monoarticular prostheses.

  15. The effect of botulinum toxin A on gastrocnemius length: magnitude and duration of response.

    Science.gov (United States)

    Eames, N W; Baker, R; Hill, N; Graham, K; Taylor, T; Cosgrove, A

    1999-04-01

    Thirty-nine ambulant children (22 with hemiplegia, 17 with diplegia) with spastic cerebral palsy receiving isolated gastrocnemius muscle injection with botulinum toxin A were studied prospectively. The children had a mean age of 6 years (range 3 to 13 years). Measurement of gastrocnemius muscle length was used to estimate the dynamic component of each child's spasticity and to quantify the response. There was a strong correlation between the dynamic component of spasticity before injection and the corresponding magnitude of the response after injection. Children undergoing repeated injections showed similar correlations. A strong correlation was found between the duration of response and the dynamic component. Children with hemiplegia showed twice the duration for a given dynamic component compared with those with diplegia when injected with the same total dose per unit body weight. Long-term lengthening did not occur for the cohort, although some patients showed a response at a 12-month follow-up. By delaying shortening, the injections may have a role in delaying the need for surgery. Injections were well tolerated with few side effects.

  16. Multiple Heads of Gastrocnemius with Bipennate Fiber Arrangement- A Clinically Significant Variation.

    Science.gov (United States)

    Rodrigues, Vincent; Rao, Mohandas Kg; Nayak, Shivananda

    2016-08-01

    It is common to have additional muscles or muscle slips in the extremities. Some of them may compress the nerves and vessels or restrict the movements, while others may enhance the muscular activity. However, a small number of them may go unnoticed. Knowledge of such variant muscles becomes important for plastic surgeons while performing various reconstructive surgeries and for clinicians while managing the pain. A case of multiple heads of gastrocnemius muscle was observed during routine dissection of the right lower limb of about 70-year-old male cadaver. It was observed that the medial head of gastrocnemius was attached to the femur with 3 thick heads and lateral head was arising from the lateral condyle of femur by 3 thick heads. All the heads of the muscles remained separate till they formed tendocalcaneus. Some of these heads showed bipinnate fiber arrangement. All the heads were innervated by the branches of tibial nerve. As the muscle heads passed down from their origin, they entrapped the sural nerve and sural nerve was seen emerging at the beginning of tendocalcaneus. Further, detailed literature and the clinical and surgical importance of the case are discussed.

  17. Measuring the multi-frequency electrical impedance of the mouse gastrocnemius muscle using a tetrapolar technique

    Science.gov (United States)

    Li, J.; Fogerson, P. M.; Rutkove, S. B.

    2010-04-01

    Electrical impedance methods can be used to evaluate and monitor neuromuscular disease states. Recently, we have applied tetrapolar surface electrical impedance methods to the gastrocnemius muscle of the rat for this purpose and substantial changes in the impedance parameters after sciatic nerve crush can be identified. In order to be able to study additional animal models of nerve and muscle disease, however, it would highly desirable to be able to perform such impedance measurements in the mouse. Yet the small size of the mouse presents a substantial technical challenge. In this study, we evaluate a basic approach for performing such measurements. A series of thin, stainless steel strip electrodes affixed to the gastrocnemius and interfaced via a separate connector to the Imp SFB7® (Impedimed, Inc), provided an effective means for obtaining impedance data in the 20-500 kHz range. After two weeks, test-retest reproducibility was good, with intra-class correlation coefficients as high 0.84 and variability as low as 12.86 ± 6.18% in the 15 mice studied. Using this approach, it may now be possible to study impedance changes in a variety of mouse models of neuromuscular disease, including amyotrophic lateral sclerosis, spinal muscular atrophy, muscular dystrophy and Charcot-Marie-Tooth disease.

  18. Redox proteomic analysis of the gastrocnemius muscle from adult and old mice

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    Brian McDonagh

    2015-09-01

    Full Text Available The data provides information in support of the research article, “Differential Cysteine Labeling and Global Label-Free Proteomics Reveals an Altered Metabolic State in Skeletal Muscle Aging”, Journal of Proteome Research, 2014, 13 (11, 2008–21 [1]. Raw data is available from ProteomeXchange [2] with identifier PDX001054. The proteome of gastrocnemius muscle from adult and old mice was analyzed by global label-free proteomics and the relative quantification of specific reduced and reversibly oxidized Cysteine (Cys residues was performed using Skyline [3]. Briefly, reduced Cysteine (Cys containing peptides was alkylated using N-ethylmalemide (d0-NEM. Samples were desalted and reversibly oxidized Cys residues were reduced using tris(2-carboxyethylphosphine (TCEP and the newly formed reduced Cys residues were labeled with heavy NEM( d5-NEM. Label-free analysis of the global proteome of adult (n=5 and old (n=4 gastrocnemius muscles was performed using Peaks7™ mass spectrometry data analysis software [4]. Relative quantification of Cys containing peptides that were identified as reduced (d(0 NEM labeled and reversibly oxidized d(5–NEM labeled was performed using the intensity of their precursor ions in Skyline. Results indicate that muscles from old mice show reduced redox flexibility particularly in proteins involved in the generation of precursor metabolites and energy metabolism, indicating a loss in the flexibility of the redox energy response.

  19. Acute Gastrocnemius-Soleus Complex Injuries in National Football League Athletes

    Science.gov (United States)

    Werner, Brian C.; Belkin, Nicole S.; Kennelly, Steve; Weiss, Leigh; Barnes, Ronnie P.; Potter, Hollis G.; Warren, Russell F.; Rodeo, Scott A.

    2017-01-01

    Background: Lower extremity muscle injuries are common in professional football. Although less common than hamstring or quadriceps injuries in National Football League (NFL) athletes, calf injuries occur with relative frequency and have not previously been studied. Purpose: To evaluate gastrocnemius-soleus complex muscle injuries over the past 13 years from a single NFL team to determine the incidence of such injuries, their imaging characteristics, and return to play after such injuries and any correlation between imaging findings and prolonged return to play. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review of all acute calf muscle injuries on a single NFL team from 2003 to 2015 was performed. Player demographics and return-to-play data were obtained from the medical records. All available magnetic resonance images (MRIs) were reviewed by a musculoskeletal radiologist for specific imaging findings that correlated with return to play. Results: A total of 27 calf injuries in 24 NFL players were reviewed, yielding an incidence of 2.3 acute calf injuries per year on a single NFL team. Of these 27 injuries, 20 (74%) were isolated injuries to the gastrocnemius muscle, 4 (15%) were isolated injuries to the soleus muscle, and the remaining 3 injuries (11%) involved both. Defensive players were more likely to sustain injuries (P = .043). The mean time to return to play for all 27 players was 17.4 ± 14.6 days (range, 3-62 days). MRIs were available in 14 of the 27 injuries. The average size of the fascial defect (P = .032) and the presence of a fluid collection (P = .031) both correlated with return to play of longer than 2 weeks. Conclusion: Although less common than hamstring or quadriceps muscle injuries, calf muscle injuries occur with relative frequency in the NFL, and more so in defensive players. The majority of these injuries occur in the gastrocnemius and result in significant disability, with at least 2 weeks of missed playing

  20. How does passive lengthening change the architecture of the human medial gastrocnemius muscle?

    Science.gov (United States)

    Bolsterlee, Bart; D'Souza, Arkiev; Gandevia, Simon C; Herbert, Robert D

    2017-04-01

    There are few comprehensive investigations of the changes in muscle architecture that accompany muscle contraction or change in muscle length in vivo. For this study, we measured changes in the three-dimensional architecture of the human medial gastrocnemius at the whole muscle level, the fascicle level and the fiber level using anatomical MRI and diffusion tensor imaging (DTI). Data were obtained from eight subjects under relaxed conditions at three muscle lengths. At the whole muscle level, a 5.1% increase in muscle belly length resulted in a reduction in both muscle width (mean change -2.5%) and depth (-4.8%). At the fascicle level, muscle architecture measurements obtained at 3,000 locations per muscle showed that for every millimeter increase in muscle-tendon length above the slack length, average fascicle length increased by 0.46 mm, pennation angle decreased by 0.27° (0.17° in the superficial part and 0.37° in the deep part), and fascicle curvature decreased by 0.18 m -1 There was no evidence of systematic variation in architecture along the muscle's long axis at any muscle length. At the fiber level, analysis of the diffusion signal showed that passive lengthening of the muscle increased diffusion along fibers and decreased diffusion across fibers. Using these measurements across scales, we show that the complex shape changes that muscle fibers, whole muscles, and aponeuroses of the medial gastrocnemius undergo in vivo cannot be captured by simple geometrical models. This justifies the need for more complex models that link microstructural changes in muscle fibers to macroscopic changes in architecture. NEW & NOTEWORTHY Novel MRI and DTI techniques revealed changes in three-dimensional architecture of the human medial gastrocnemius during passive lengthening. Whole muscle belly width and depth decreased when the muscle lengthened. Fascicle length, pennation, and curvature changed uniformly or near uniformly along the muscle during passive lengthening

  1. Modeling of surface myoelectric signals--Part II: Model-based signal interpretation.

    Science.gov (United States)

    Merletti, R; Roy, S H; Kupa, E; Roatta, S; Granata, A

    1999-07-01

    Experimental electromyogram (EMG) data from the human biceps brachii were simulated using the model described in [10] of this work. A multichannel linear electrode array, spanning the length of the biceps, was used to detect monopolar and bipolar signals, from which double differential signals were computed, during either voluntary or electrically elicited isometric contractions. For relatively low-level voluntary contractions (10%-30% of maximum force) individual firings of three to four-different motor units were identified and their waveforms were closely approximated by the model. Motor unit parameters such as depth, size, fiber orientation and length, location of innervation and tendonous zones, propagation velocity, and source width were estimated using the model. Two applications of the model are described. The first analyzes the effects of electrode rotation with respect to the muscle fiber direction and shows the possibility of conduction velocity (CV) over- and under-estimation. The second focuses on the myoelectric manifestations of fatigue during a sustained electrically elicited contraction and the interrelationship between muscle fiber CV, spectral and amplitude variables, and the length of the depolarization zone. It is concluded that a) surface EMG detection using an electrode array, when combined with a model of signal propagation, provides a useful method for understanding the physiological and anatomical determinants of EMG waveform characteristics and b) the model provides a way for the interpretation of fatigue plots.

  2. Using gastrocnemius sEMG and plasma α-synuclein for the prediction of freezing of gait in Parkinson's disease patients.

    Directory of Open Access Journals (Sweden)

    Xiao-Ying Wang

    Full Text Available Freezing of gait (FOG is a complicated gait disturbance in Parkinson's disease (PD and a relevant subclinical predictor algorithm is lacking. The main purpose of this study is to explore the potential value of surface electromyograph (sEMG and plasma α-synuclein levels as predictors of the FOG seen in PD. 21 PD patients and 15 normal controls were recruited. Motor function was evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS and Freezing of gait questionnaire (FOG-Q. Simultaneously, gait analysis was also performed using VICON capture system in PD patients and sEMG data was recorded as well. Total plasma α-synuclein was quantitatively assessed by Luminex assay in all participants. Recruited PD patients were classified into two groups: PD patients with FOG (PD+FOG and without FOG (PD-FOG, based on clinical manifestation, the results of the FOG-Q and VICON capture system. PD+FOG patients displayed higher FOG-Q scores, decreased walking speed, smaller step length, smaller stride length and prolonged double support time compared to the PD-FOG in the gait trial. sEMG data indicated that gastrocnemius activity in PD+FOG patients was significantly reduced compared to PD-FOG patients. In addition, plasma α-synuclein levels were significantly decreased in the PD+FOG group compared to control group; however, no significant difference was found between the PD+FOG and PD-FOG groups. Our study revealed that gastrocnemius sEMG could be used to evaluate freezing gait in PD patients, while plasma α-synuclein might discriminate freezing of gait in PD patients from normal control, though no difference was found between the PD+FOG and PD-FOG groups.

  3. G-LOC Warning Algorithms Based on EMG Features of the Gastrocnemius Muscle.

    Science.gov (United States)

    Kim, Sungho; Cho, Taehwan; Lee, Yongkyun; Koo, Hyojin; Choi, Booyong; Kim, Dongsoo

    2017-08-01

    G-induced loss of consciousness (G-LOC) is mainly caused by failure to sustain an oxygenated blood supply to the pilot's brain because of the sudden acceleration in the direction of the +Gz axis, and is considered a critical safety issue. The purpose of this study was to develop G-LOC warning algorithms based on monitoring electromyograms (EMG) of the gastrocnemius muscle on the calf. EMG data was retrieved from a total of 67 pilots and pilot trainees of the Korean Air Force during high-G training on a human centrifugal simulator. Seven EMG features were obtained from root mean square (RMS), integrated absolute value (IAV), and mean absolute value (MAV) for muscle contraction, slope sign changes (SSC), waveform length (WL), zero crossing (ZC), and median frequency (MF) for muscle contraction and fatigue. Out of seven EMG features, IAV and WL showed a rapid decay before G-LOC. Based on these findings, this study developed two algorithms which can detect G-LOC during flight and provide warning signals to the pilots. The probability of G-LOC occurrence was detected through monitoring the decay trend for representing muscle endurance and climb rate of the IAV and WL value during sudden acceleration above 6 G, representing muscle power. The sensitivity of the algorithms using IAV and WL features was 100% and the specificity was 66.7%. This study suggests that a G-LOC detecting and warning system may be a customized, real-time countermeasure by improving the accuracy of detecting G-LOC.Kim S, Cho T, Lee Y, Koo H, Choi B, Kim D. G-LOC warning algorithms based on EMG features of the gastrocnemius muscle. Aerosp Med Hum Perform. 2017; 88(8):737-742.

  4. Low-frequency fatigue is fiber type related and most pronounced after eccentric activity in rat medial gastrocnemius muscle

    NARCIS (Netherlands)

    Rijkelijkhuizen, J.M.; de Ruiter, C.J.; Huijing, P.A.J.B.M.; de Haan, A.

    2003-01-01

    Effects of fibre type composition and type of contraction on low-frequency fatigue (LFF) were investigated in isolated rat medial gastrocnemius (GM) muscle. Fast oxidative or fast glycolytic GM muscle parts of anaesthetised male Wistar rats (n=18) were activated selectively by maximal electrical

  5. Influence of the gastrocnemius muscle on the sit-and-reach test assessed by angular kinematic analysis.

    Science.gov (United States)

    Kawano, Marcio M; Ambar, Gabriel; Oliveira, Beatriz I R; Boer, Marcela C; Cardoso, Ana P R G; Cardoso, Jefferson R

    2010-01-01

    The sit-and-reach test (SRT) used to measure low back and hamstring flexibility is more adequate when combined with hip joint angle (HJA) measurement. It is supposed that shortening of the gastrocnemius muscle could affect the SRT results. The purposes of the study were to investigate the relationship between the HJA and SRT and to verify the influence of the gastrocnemius. This is a cross-sectional study on healthy subjects. Two hundred subjects took part in the study: 100 males and 100 females aged 21.2 years (SD=1.7). The materials used were a sit-and-reach box with an adapted door to evaluate the influence of the gastrocnemius and a digital camera. Skin markers were positioned on the anterior superior iliac spine and greater trochanter. Two pictures were taken in the final position of the test, one with the door closed (with ankle dorsiflexed - DF) and the other with the door opened (with ankle plantarflexed - PF). Moderate correlation was found between the HJA and SRT for DF and PF (r=0.48 e 0.44). The HJA with DF and PF were 95.5 masculine+/-18.6 masculine and 99.7 masculine+/-18 masculine (P<0.001), respectively. Angular kinematic analysis is a reliable technique to measure the HJA. The results demonstrated the influence of the gastrocnemius; thus we suggest that the SRT be performed with free ankle joint mobility.

  6. Attenuated increase in maximal force of rat medial gastrocnemius muscle after concurrent peak power and endurance training

    NARCIS (Netherlands)

    Furrer, R.; Jaspers, R.T.; Baggerman, H.L.; Bravenboer, N.; Lips, P.; de Haan, A.

    2013-01-01

    Improvement of muscle peak power and oxidative capacity are generally presumed to be mutually exclusive. However, this may not be valid by using fibre type-specific recruitment. Since rat medial gastrocnemius muscle (GM) is composed of high and low oxidative compartments which are recruited task

  7. Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy.

    Science.gov (United States)

    Barber, Lee; Barrett, Rod; Lichtwark, Glen

    2012-10-11

    Individuals with spastic cerebral palsy (CP) typically experience muscle weakness. The mechanisms responsible for muscle weakness in spastic CP are complex and may be influenced by the intrinsic mechanical properties of the muscle and tendon. The purpose of this study was to investigate the medial gastrocnemius (MG) muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic CP. Nine relatively high functioning young adults with spastic CP (GMFCS I, 17±2 years) and 10 typically developing individuals (18±2 years) participated in the study. Active MG torque-length and Achilles tendon properties were assessed under controlled conditions on a dynamometer. EMG was recorded from leg muscles and ultrasound was used to measure MG fascicle length and Achilles tendon length during maximal isometric contractions at five ankle angles throughout the available range of motion and during passive rotations imposed by the dynamometer. Compared to the typically developing group, the spastic CP group had 33% lower active ankle plantarflexion torque across the available range of ankle joint motion, partially explained by 37% smaller MG muscle and 4% greater antagonistic co-contraction. The Achilles tendon slack length was also 10% longer in the spastic CP group. This study confirms young adults with mild spastic CP have altered muscle-tendon mechanical properties. The adaptation of a longer Achilles tendon may facilitate a greater storage and recovery of elastic energy and partially compensate for decreased force and work production by the small muscles of the triceps surae during activities such as locomotion. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Applying Space Technology to Enhance Control of an Artificial Arm

    Science.gov (United States)

    Atkins, Diane; Donovan, William H.; Novy, Mara; Abramczyk, Robert

    1997-01-01

    At the present time, myoelectric prostheses perform only one function of the hand: open and close with the thumb, index and middle finger coming together to grasp various shaped objects. To better understand the limitations of the current single-function prostheses and the needs of the individuals who use them, The Institute for Rehabilitation and Research (TIRR), sponsored by the National Institutes of Health (August 1992 - November 1994), surveyed approximately 2500 individuals with upper limb loss. When asked to identify specific features of their current electric prosthesis that needed improvement, the survey respondents overwhelmingly identified the lack of wrist and finger movement as well as poor control capability. Simply building a mechanism with individual finger and wrist motion is not enough. Individuals with upper limb loss tend to reject prostheses that require continuous visual monitoring and concentration to control. Robotics researchers at NASA's Johnson Space Center (JSC) and Rice University have made substantial progress in myoelectric teleoperation. A myoelectric teleoperation system translates signals generated by an able-bodied robot operator's muscles during hand motions into commands that drive a robot's hand through identical motions. Farry's early work in myoelectric teleoperation used variations over time in the myoelectric spectrum as inputs to neural networks to discriminate grasp types and thumb motions. The resulting schemes yielded up to 93% correct classification on thumb motions. More recently, Fernandez achieved 100% correct non-realtime classification of thumb abduction, extension, and flexion on the same myoelectric data. Fernandez used genetic programming to develop functions that discriminate between thumb motions using myoelectric signal parameters. Genetic programming (GP) is an evolutionary programming method where the computer can modify the discriminating functions' form to improve its performance, not just adjust

  9. Voluntary wheel running increases satellite cell abundance and improves recovery from disuse in gastrocnemius muscles from mice.

    Science.gov (United States)

    Brooks, Matthew J; Hajira, Ameena; Mohamed, Junaith S; Alway, Stephen E

    2018-02-22

    Reloading of atrophied muscles after hindlimb suspension unloading (HSU) can induce injury and prolong recovery. Low-impact exercise, such as voluntary wheel running, has been identified as a non-damaging rehabilitation therapy in rodents, but its effects on muscle function, morphology, and satellite cell activity after HSU are unclear. This study tested the hypothesis that low impact wheel running would increase satellite cell proliferation and improve recovery of muscle structure and function after HSU in mice. Young adult male and female C57BL/6 mice (n=6/group) were randomly placed into 5 groups. These included HSU without recovery (HSU), normal ambulatory recovery for 14 days after HSU (HSU+NoWR), and voluntary wheel running recovery for 14 days after HSU (HSU+WR). Two control groups were used: non-suspended mice-cage controls (Control) and voluntary wheel running controls (ControlWR). Satellite cell activation, was evaluated by providing mice 5-bromo-2'-deoxyuridine (BrdU) in their drinking water. As expected, HSU significantly reduced in vivo maximal force and decreased the in vivo fatigability and decreased type I and IIa myosin heavy chain (MHC) abundance in plantarflexor muscles. HSU+WR mice significantly improved plantarflexor fatigue resistance, increased type type I and IIa MHC abundance, increased fiber cross sectional area (CSA), and an increased the percentage of type I and IIA muscle fibers in the gastrocnemius muscle. HSU+WR mice also had a significantly greater percentage of BrdU-positive and Pax 7 positive nuclei inside muscle fibers and a greater MyoD to Pax 7 protein ratio when compared to HSU+NoWR mice. The mechanotransduction protein Yes-associated protein (YAP) was elevated with reloading after HSU, but HSU+WR had lower levels of the inactive phosphorylated YAP serine127 which may have contributed to increased satellite cell activation creased with reloading after HSU. These results indicate that voluntary wheel running increased YAP

  10. Applying Space Technology to Enhance Control of an Artificial Arm for Children and Adults With Amputations

    Science.gov (United States)

    Atkins, Diane J.

    1998-01-01

    The first single function myoelectric prosthetic hand was introduced in the 1960's. This hand was controlled by the electric fields generated by muscle contractions in the residual limb of the amputee user. Electrodes and amplifiers, embedded in the prosthetic socket, measured these electric fields across the skin, which increase in amplitude as the individual contracts their muscle. When the myoelectric signal reached a certain threshold amplitude, the control unit activated a motor which opened or closed a hand-like prosthetic terminal device with a pincher grip. Late in the 1990's, little has changed. Most current myoelectric prostheses still operate in this same, single-function way. To better understand the limitations of the current single-function myoelectric hand and the needs of those who use them, The Institute for Rehabilitation and Research (TIRR), sponsored by the National Institutes of Health (NUH), surveyed approximately 2,500 individuals with upper limb loss [1]. When asked to identify specific features of their current myoelectric prostheses that needed improvement, the survey respondents overwhelmingly identified the lack of wrist and finger movement, as well as poor control capability. However, simply building a mechanism with individual finger and wrist motion is not enough. In the 1960's and 1970's, engineers built a number of more dexterous prosthetic hands. Unfortunately, these were rejected during clinical trials due to a difficult and distracting control interface. The goal of this project, "Applying Space Technology to Enhance Control of an Artificial Arm for Children and Adults with Amputations," was to lay the foundation for a multi-function, intuitive myoelectric control system which requires no conscious thought to move the hand. We built an extensive myoelectric signal database for six motions from ten amputee volunteers, We also tested a control system based on new artificial intelligence techniques on the data from two of these

  11. Robotic Hand-Assisted Training for Spinal Cord Injury Driven by Myoelectric Pattern Recognition: A Case Report.

    Science.gov (United States)

    Lu, Zhiyuan; Tong, Kai-Yu; Shin, Henry; Stampas, Argyrios; Zhou, Ping

    2017-10-01

    A 51-year-old man with an incomplete C6 spinal cord injury sustained 26 yrs ago attended twenty 2-hr visits over 10 wks for robot-assisted hand training driven by myoelectric pattern recognition. In each visit, his right hand was assisted to perform motions by an exoskeleton robot, while the robot was triggered by his own motion intentions. The hand robot was designed for this study, which can perform six kinds of motions, including hand closing/opening; thumb, index finger, and middle finger closing/opening; and middle, ring, and little fingers closing/opening. After the training, his grip force increased from 13.5 to 19.6 kg, his pinch force remained the same (5.0 kg), his score of Box and Block test increased from 32 to 39, and his score from the Graded Redefined Assessment of Strength, Sensibility, and Prehension test Part 4.B increased from 22 to 24. He accomplished the tasks in the Graded Redefined Assessment of Strength, Sensibility, and Prehension test Part 4.B 28.8% faster on average. The results demonstrate the feasibility and effectiveness of robot-assisted training driven by myoelectric pattern recognition after spinal cord injury.

  12. High-density EMG e-textile systems for the control of active prostheses

    DEFF Research Database (Denmark)

    Farina, Dario; Lorrain, Thomas; Negro, Francesco

    2010-01-01

    Myoelectric control of active prostheses requires electrode systems that are easy to apply for daily repositioning of the electrodes by the user. In this study we propose the use of Smart Fabric and Interactive Textile (SFIT) systems as an alternative solution for recording high-density EMG signals...... for myoelectric control. A sleeve covering the upper and lower arm, which contains 100 electrodes arranged in four grids of 5 * 5 electrodes, was used to record EMG signals in 3 subjects during the execution of 9 tasks of the wrist and hand. The signals were analyzed by extracting wavelet coefficients which were...

  13. Excessive gastrocnemius fibrosis developed after radiofrequency-induced cosmetic volume reduction.

    Science.gov (United States)

    Hwang, Chang Ho

    2011-12-01

    Cosmetic shaping of the lower leg is becoming increasingly popular. The use of radiofrequency therapy in cosmetic medicine also is growing. To date, no serious complications have been reported after the use of cosmetic radiofrequency therapy. This report describes a patient who presented at the author's clinic with a disabling ankle plantarflexion contracture in both calves that developed during a period of 18 months after cosmetic radiofrequency volume reduction. This reduction, performed at another clinic, involved applying a bipolar electrode with a mean power of 35 W at each of approximately 100 spots for 2 to 4 s. On each calf, 15 kJ was applied in a crisscross fashion. Magnetic resonance imaging and muscle biopsy indicated excessive gastrocnemius fibrosis. The patient was treated using botulinum toxin injections followed by serial castings and intensive physiotherapy. After treatment, the patient was able to walk with less difficulty and showed no tiptoeing. This appears to be the first report of serious muscle contracture after cosmetic radiofrequency volume reduction requiring extensive rehabilitation management.

  14. Hybrid diffuse optical techniques for continuous hemodynamic measurement in gastrocnemius during plantar flexion exercise

    Science.gov (United States)

    Henry, Brad; Zhao, Mingjun; Shang, Yu; Uhl, Timothy; Thomas, D. Travis; Xenos, Eleftherios S.; Saha, Sibu P.; Yu, Guoqiang

    2015-12-01

    Occlusion calibrations and gating techniques have been recently applied by our laboratory for continuous and absolute diffuse optical measurements of forearm muscle hemodynamics during handgrip exercises. The translation of these techniques from the forearm to the lower limb is the goal of this study as various diseases preferentially affect muscles in the lower extremity. This study adapted a hybrid near-infrared spectroscopy and diffuse correlation spectroscopy system with a gating algorithm to continuously quantify hemodynamic responses of medial gastrocnemius during plantar flexion exercises in 10 healthy subjects. The outcomes from optical measurement include oxy-, deoxy-, and total hemoglobin concentrations, blood oxygen saturation, and relative changes in blood flow (rBF) and oxygen consumption rate (rV˙O2). We calibrated rBF and rV˙O2 profiles with absolute baseline values of BF and V˙O2 obtained by venous and arterial occlusions, respectively. Results from this investigation were comparable to values from similar studies. Additionally, significant correlation was observed between resting local muscle BF measured by the optical technique and whole limb BF measured concurrently by a strain gauge venous plethysmography. The extensive hemodynamic and metabolic profiles during exercise will allow for future comparison studies to investigate the diagnostic value of hybrid technologies in muscles affected by disease.

  15. Effect of carnitine supplementation on fatigue level in the gastrocnemius muscle of trained and sedentary rats

    Directory of Open Access Journals (Sweden)

    Rossana Anelice Gomez

    2012-04-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p324 L-carnitine, considered to be of great value in metabolic processes, plays an important role in the mitochondrial β-oxidation process. It may be used to improve athletic performance and to maintain a higher workload during exercise. This study aimed to investigate the effect of L-carnitine supplementation on muscle fatigue in sciatic nerve-gastrocnemius muscle preparations in sedentary and trained rats. The animals were divided into 4 groups: non-supplemented sedentary (NSS, supplemented sedentary (SS, non-supplemented trained (NST, and supplemented trained (ST rats. The animals were trained in daily 1-h sessions (5 days/week and received chronic oral L-carnitine supplementation (1 mg/mL for 4 weeks. Muscle fatigue was determined by supramaximal tetanic stimulation of the sciatic nerve (50 Hz. Time values for strength reduction were significantly different (p<0.05 between NSS vs. SS and NST vs. ST rats. No significant differences were observed between SS vs. ST and NST vs. NSS rats. These findings demonstrate that L-carnitine lengthen the time required for induction of muscle fatigue.

  16. Dynamic measurement of pennation angle of gastrocnemius muscles during contractions based on ultrasound imaging

    Directory of Open Access Journals (Sweden)

    Zhou Yongjin

    2012-09-01

    Full Text Available Abstract Background Muscle fascicle pennation angle (PA is an important parameter related to musculoskeletal functions, and ultrasound imaging has been widely used for measuring PA, but manually and frame by frame in most cases. We have earlier reported an automatic method to estimate aponeurosis orientation based on Gabor transform and Revoting Hough Transform (RVHT. Methods In this paper, we proposed a method to estimate the overall orientation of muscle fascicles in a region of interest, in order to complete computing the orientation of the other side of the pennation angle, but the side found by RVHT. The measurements for orientations of both fascicles and aponeurosis were conducted in each frame of ultrasound images, and then the dynamic change of pennation angle during muscle contraction was obtained automatically. The method for fascicle orientation estimation was evaluated using synthetic images with different noise levels and later on 500 ultrasound images of human gastrocnemius muscles during isometric plantarflexion. Results The muscle fascicle orientations were also estimated manually by two operators. From the results it’s found that the proposed automatic method demonstrated a comparable performance to the manual method. Conclusions With the proposed methods, ultrasound measurement for muscle pennation angles can be more widely used for functional assessment of muscles.

  17. Passive Muscle-Tendon Unit Gearing is Joint Dependent in Human Medial Gastrocnemius

    Directory of Open Access Journals (Sweden)

    Emma F Hodson-Tole

    2016-03-01

    Full Text Available Skeletal muscles change length and develop force both passively and actively. Gearing allows muscle fibre length changes to be uncoupled from those of the whole muscle-tendon unit. During active contractions this process allows muscles to operate at mechanically favorable conditions for power or economical force production. Here we ask whether gearing is constant in passive muscle; determining the relationship between fascicle and muscle-tendon unit length change in the bi-articular medial gastrocnemius and investigating the influence of whether motion occurs at the knee or ankle joint. Specifically, the same muscle-tendon unit length changes were elicited by rotating either the ankle or knee joint whilst simultaneously measuring fascicle lengths in proximal and distal muscle regions using B-mode ultrasound. In both the proximal and distal muscle region, passive gearing values differed depending on whether ankle or knee motion occurred. Fascicle length changes were greater with ankle motion, likely reflecting anatomical differences in proximal and distal passive tendinous tissues, as well as shape changes of the adjacent mono-articular soleus. This suggests that there is joint-dependent dissociation between the mechanical behaviour of muscle fibres and the muscle-tendon unit during passive joint motions that may be important to consider when developing accurate models of bi-articular muscles.

  18. The effect of temperature on eccentric contraction-induced isometric force loss in isolated perfused rat medial gastrocnemius muscle

    OpenAIRE

    Vasaghi Gharamaleki B; Keshavarz M; Gharibzadeh Sh; Marvi H; Mosayebnejad J; Ebrahimi Takamjani E

    2008-01-01

    "nBackground: The typical features of eccentric exercise-induced muscle damage are delayed-onset muscle soreness (DOMS) and prolonged loss of muscle strength. It has been shown that passive warmth is effective in reducing muscle injury. Due to the interaction of different systems in vivo, we used isolated perfused medial gastrocnemius skeletal muscle to study the direct effect of temperature on the eccentric contraction-induced force loss. "nMethods: After femoral artery cannulation...

  19. The effect of temperature on eccentric contraction-induced isometric force loss in isolated perfused rat medial gastrocnemius muscle

    Directory of Open Access Journals (Sweden)

    Vasaghi Gharamaleki B

    2008-09-01

    Full Text Available "nBackground: The typical features of eccentric exercise-induced muscle damage are delayed-onset muscle soreness (DOMS and prolonged loss of muscle strength. It has been shown that passive warmth is effective in reducing muscle injury. Due to the interaction of different systems in vivo, we used isolated perfused medial gastrocnemius skeletal muscle to study the direct effect of temperature on the eccentric contraction-induced force loss. "nMethods: After femoral artery cannulation of a rat, the left medial gastrocnemius muscle was separated and then the entire lower limb was transferred into a prewarmed (35oC chamber. With the chamber temperature at 31, 35 and 39oC before and during eccentric contraction. Isometric force loss was measured after 15 eccentric contractions (N=7-9. "nResults: Maximum contraction force reduction has been used as an index for eccentric contraction-induced force loss. In this study eccentric contraction caused a significant reduction in maximum isometric tension (p<0.01, but no significant difference was seen in isometric force loss at 31oC and 39oC compared with that at 35oC. "nConclusions: Our results suggest that temperature changes before or during eccentric contractions have no effect on eccentric contraction-induced force loss. "nKeywords: Isolated perfused muscle, skeletal muscle, eccentric contractions, isometric force, gastrocnemius muscle, temperature.

  20. Oedema and fatty degeneration of the soleus and gastrocnemius muscles on MR images in patients with achilles tendon abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Adrienne [University Hospital Balgrist Zuerich, Radiology Department, Zuerich (Switzerland); Hirslanden Klinik Aarau, Radiology Department, Aarau (Switzerland); Mamisch, Nadja; Buck, Florian M.; Pfirrmann, Christian W.A.; Zanetti, Marco [University Hospital Balgrist Zuerich, Radiology Department, Zuerich (Switzerland); Espinosa, Norman [University Hospital Balgrist Zuerich, Orthopedic Surgery Department, Zuerich (Switzerland)

    2011-09-15

    The purpose of this study was to evaluate the frequency of oedema and fatty degeneration of the soleus and gastrocnemius muscles in patients with Achilles tendon abnormalities. Forty-five consecutive patients (mean 51 years; range 14-84 years) with achillodynia were examined with magnetic resonance (MR) images of the calf. The frequency of oedema and fatty degeneration in the soleus and gastrocnemius muscles was determined in patients with normal tendons, tendinopathy and in patients with a partial tear or a complete tear of the Achilles tendon. Oedema was encountered in 35% (7/20) of the patients with tendinopathy (n = 20; range 13-81 years), and in 47% (9/19) of the patients with partial tears or complete tears (n = 19; 28-78 years). Fatty degeneration was encountered in 10% (2/20) of the patients with tendinopathy, and in 32% (6/19) of the patients with tears. The prevalence of fatty degeneration was significantly more common in patients with a partial or complete tear compared with the patients with a normal Achilles tendon (p = 0.032 and p = 0.021, respectively). Oedema and fatty degeneration of the soleus and gastrocnemius muscles are common in patients with Achilles tendon abnormalities. (orig.)

  1. A preliminary study of the effect of restricted gastrocnemius length on foot kinematics and plantar pressure patterns during gait in children with Cerebral Palsy

    DEFF Research Database (Denmark)

    Curtis, Derek

    2008-01-01

    forefoot mean plantar pressure and force in the children with gastrocnemius contracture, whilst the corresponding changes in foot kinematics were non-significant.   Introduction Foot deformity is common in CP and is often due to hypertonia and contracture in spastic muscles. The aim of this study...... was to establish the repeatability of two measurement techniques and establish whether they could be used in the quantification of altered foot kinematics and kinetics that result from gastrocnemius contracture.   Method The gait of 8 healthy children selected at random (5 girls, 3 boys, mean ± SD, 12 ± 3 yrs...... and gastrocnemius contracture were subsequently tested using the same test protocol.   Results Gastrocnemius contracture in children with CP significantly increased the mean pressure and force under the lateral forefoot during second rocker and reduced the mean pressure and force on the heel in first and second...

  2. TIME COURSE CHANGE OF IGF1/AKT/MTOR/P70S6K PATHWAY ACTIVATION IN RAT GASTROCNEMIUS MUSCLE DURING REPEATED BOUTS OF ECCENTRIC EXERCISE

    Directory of Open Access Journals (Sweden)

    Eisuke Ochi

    2010-06-01

    Full Text Available The purpose of this study was to examine whether insulin-like growth factor (IGF-1 and Akt/mTOR/p70S6K pathway activity is altered by chronic eccentric exercise in rat medial gastrocnemius muscle. Male Wistar rats (n = 24 were randomly assigned to 1 of the 2 groups: eccentric exercise (ECC group or sham-operated control (CON group. Rats in the ECC group were trained every second day for 10 days (5 sessions in total or 20 days (10 sessions in total. After either 5 or 10 exercise sessions, muscle specimens were dissected and weighed. The mRNA expression of IGF-1 and its variant, mechano growth factor (MGF, was evaluated using real time reverse transcriptase-polymerase chain reaction (RT-PCR. Tissue concentrations of Akt (P, mTOR (P, and p70S6K (P were measured by using western blot analysis. The medial gastrocnemius muscle mass of the ECC group did not show any significant difference after 5 exercise sessions, whereas the muscle mass increased significantly after 10 exercise sessions with a concomitant increase in the cross-sectional area of muscle fibers (p < 0.05. The expression of IGF-1 mRNA and the tissue concentrations of Akt (P and p70S6K (P after 10 exercise sessions was significantly higher than those of the age-matched controls and the rats that received 5 exercise sessions. The expression of MGF mRNA in both ECC5S and ECC10S were significantly higher than that in each period-matched control (p < 0.01. The tissue concentration of mTOR (P after 10 sessions showed a significant increase when compared with period-matched controls (p < 0.01. These results suggest that activation of the IGF-1/Akt/mTOR/p70S6K signaling pathway becomes dominant in the later phase of chronic exercise, when significant muscular hypertrophy is observed

  3. Therapeutic Effect of Extracorporeal Shock Wave Therapy According to Treatment Session on Gastrocnemius Muscle Spasticity in Children With Spastic Cerebral Palsy: A Pilot Study.

    Science.gov (United States)

    Park, Dong-Soon; Kwon, Dong Rak; Park, Gi-Young; Lee, Michael Y

    2015-12-01

    To investigate the therapeutic effect of extracorporeal shockwave therapy (ESWT) according to treatment session on gastrocnemius muscle spasticity in children with spastic cerebral palsy (CP). Twelve children with spastic CP underwent 1 ESWT and 2 sham ESWT sessions for gastrocnemius (group 1) or 3 ESWT sessions (group 2) once per week for 3 weeks. Modified Ashworth Scale (MAS) score, passive range of motion (PROM) of the ankle plantar-flexor muscles with knee extension, and median red pixel intensity (RPI) of color histogram of medial gastrocnemius on real-time sonoelastography (RTS) were measured before ESWT, immediately after the first and third ESWT, and at 4 weeks after the third ESWT. Mean ankle PROM was significantly increased whereas as mean ankle MAS and median gastrocnemius RPI were significantly decreased in both groups after the first ESWT. Clinical and RTS parameters before ESWT were not significantly different from those immediately after the third ESWT or at 4 weeks after the third ESWT in group 1. However, they were significantly different from those immediately after the third ESWT or at 4 weeks after the third ESWT in group 2. Mean ankle PROM, mean ankle MAS, and median gastrocnemius RPI in group 2 were significantly different from that in group 1 at 4 weeks or immediately after the third ESWT. The therapeutic effect of ESWT on spastic medial gastrocnemius in children with spastic CP is dependent on the number of ESWT sessions.

  4. Therapeutic Effect of Extracorporeal Shock Wave Therapy According to Treatment Session on Gastrocnemius Muscle Spasticity in Children With Spastic Cerebral Palsy: A Pilot Study

    Science.gov (United States)

    Park, Dong-Soon; Park, Gi-Young; Lee, Michael Y.

    2015-01-01

    Objective To investigate the therapeutic effect of extracorporeal shockwave therapy (ESWT) according to treatment session on gastrocnemius muscle spasticity in children with spastic cerebral palsy (CP). Methods Twelve children with spastic CP underwent 1 ESWT and 2 sham ESWT sessions for gastrocnemius (group 1) or 3 ESWT sessions (group 2) once per week for 3 weeks. Modified Ashworth Scale (MAS) score, passive range of motion (PROM) of the ankle plantar-flexor muscles with knee extension, and median red pixel intensity (RPI) of color histogram of medial gastrocnemius on real-time sonoelastography (RTS) were measured before ESWT, immediately after the first and third ESWT, and at 4 weeks after the third ESWT. Results Mean ankle PROM was significantly increased whereas as mean ankle MAS and median gastrocnemius RPI were significantly decreased in both groups after the first ESWT. Clinical and RTS parameters before ESWT were not significantly different from those immediately after the third ESWT or at 4 weeks after the third ESWT in group 1. However, they were significantly different from those immediately after the third ESWT or at 4 weeks after the third ESWT in group 2. Mean ankle PROM, mean ankle MAS, and median gastrocnemius RPI in group 2 were significantly different from that in group 1 at 4 weeks or immediately after the third ESWT. Conclusion The therapeutic effect of ESWT on spastic medial gastrocnemius in children with spastic CP is dependent on the number of ESWT sessions. PMID:26798605

  5. Isolated gastrocnemius and soleal vein thrombosis: should these patients receive therapeutic anticoagulation?

    Science.gov (United States)

    Lautz, Timothy B; Abbas, Farah; Walsh, Sarah J Novis; Chow, Christopher; Amaranto, Daniel J; Wang, Edward; Blackburn, Donna; Pearce, William H; Kibbe, Melina R

    2010-04-01

    To determine the incidence of isolated gastrocnemius and soleal vein thrombosis (IGSVT) and the effect of anticoagulation on venous thromboembolism (VTE) events in patients with IGSVT. Although IGSVT is diagnosed with increasing frequency, the clinical significance and optimal management remains unknown. Vascular laboratory studies from April 2002 to April 2007 were retrospectively reviewed to identify patients with IGSVT. Medical records were reviewed for demographic data, risk factors, treatment modalities, and VTE events. Univariate and multivariate analysis were performed. Of 38,426 lower extremity venous duplex studies, 406 patients with IGSVT were included in this study. Mean follow-up was 7.5 +/- 11 months. The overall incidence of VTE among the entire cohort was 18.7%, which included 3.9% pulmonary embolism and 16.3% deep venous thrombosis, with 1.5% of patients having both pulmonary embolism and deep venous thrombosis. However, the incidence of VTE was 30% (36/119) and 27% (13/48) in patients who received no or prophylactic anticoagulation, respectively, but only 12% in patients treated with therapeutic anticoagulation (23/188; P = 0.0003). Multivariate analysis identified lack of therapeutic anticoagulation (P = 0.017) and history of VTE (P = 0.011) as independent predictors of subsequent VTE development. The rate of IGSVT resolution during follow up was 61.2% with therapeutic anticoagulation, but only 40.0% and 41.0% with prophylactic or no anticoagulation, respectively (P = 0.003). IGSVT is associated with a clinically significant rate of VTE which is dramatically reduced with therapeutic anticoagulation. These data warrant further investigation, taking into account the risks and benefits of anticoagulation.

  6. Shifting gears: dynamic muscle shape changes and force-velocity behavior in the medial gastrocnemius.

    Science.gov (United States)

    Dick, Taylor J M; Wakeling, James M

    2017-12-01

    When muscles contract, they bulge in thickness or in width to maintain a (nearly) constant volume. These dynamic shape changes are tightly linked to the internal constraints placed on individual muscle fibers and play a key functional role in modulating the mechanical performance of skeletal muscle by increasing its range of operating velocities. Yet to date we have a limited understanding of the nature and functional implications of in vivo dynamic muscle shape change under submaximal conditions. This study determined how the in vivo changes in medial gastrocnemius (MG) fascicle velocity, pennation angle, muscle thickness, and subsequent muscle gearing varied as a function of force and velocity. To do this, we obtained recordings of MG tendon length, fascicle length, pennation angle, and thickness using B-mode ultrasound and muscle activation using surface electromyography during cycling at a range of cadences and loads. We found that that increases in contractile force were accompanied by reduced bulging in muscle thickness, reduced increases in pennation angle, and faster fascicle shortening. Although the force and velocity of a muscle contraction are inversely related due to the force-velocity effect, this study has shown how dynamic muscle shape changes are influenced by force and not influenced by velocity. NEW & NOTEWORTHY During movement, skeletal muscles contract and bulge in thickness or width. These shape changes play a key role in modulating the performance of skeletal muscle by increasing its range of operating velocities. Yet to date the underlying mechanisms associated with muscle shape change remain largely unexplored. This study identified muscle force, and not velocity, as the mechanistic driving factor to allow for muscle gearing to vary depending on the contractile conditions during human cycling. Copyright © 2017 the American Physiological Society.

  7. Characteristics of myogenic response and ankle torque recovery after lengthening contraction-induced rat gastrocnemius injury

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    Song Hongsun

    2012-10-01

    Full Text Available Abstract Background Although muscle dysfunction caused by unfamiliar lengthening contraction is one of most important issues in sports medicine, there is little known about the molecular events on regeneration process. The purpose of this study was to investigate the temporal and spatial expression patterns of myogenin, myoD, pax7, and myostatin after acute lengthening contraction (LC-induced injury in the rat hindlimb. Methods We employed our originally developed device with LC in rat gastrocnemius muscle (n = 24. Male Wistar rats were anesthetized with isoflurane (aspiration rate, 450 ml/min, concentration, 2.0%. The triceps surae muscle of the right hindlimb was then electrically stimulated with forced isokinetic dorsi-flexion (180°/sec and from 0 to 45°. Tissue contents of myoD, myogenin, pax7, myostatin were measured by western blotting and localizations of myoD and pax7 was measured by immunohistochemistry. After measuring isometric tetanic torque, a single bout of LC was performed in vivo. Results The torque was significantly decreased on days 2 and 5 as compared to the pre-treatment value, and recovered by day 7. The content of myoD and pax7 showed significant increases on day 2. Myogenin showed an increase from day 2 to 5. Myostatin on days 5 and 7 were significantly increased. Immunohistochemical analysis showed that myoD-positive/pax7-positive cells increased on day 2, suggesting that activated satellite cells play a role in the destruction and the early recovery phases. Conclusion We, thus, conclude that myogenic events associate with torque recovery after LC-induced injury.

  8. Within- and between-session reliability of medial gastrocnemius architectural properties

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    JJ McMahon

    2016-05-01

    Full Text Available This study aimed to determine the within- and between-session reliability of medial gastrocnemius (MG architecture (e.g. muscle thickness (MT, fascicle length (FL and pennation angle (PA, as derived via ultrasonography followed by manual digitization. A single rater recorded three ultrasound images of the relaxed MG muscle belly for both legs of 16 resistance trained males, who were positioned in a pronated position with their knees fully extended and the ankles in a neutral (e.g. 90° position. A subset of participants (n = 11 were retested under the same conditions ~48-72 hours after baseline testing. The same rater manually digitized each ultrasound image on three occasions to determine MG MT, FL and PA before pooling the data accordingly to allow for within-image (n = 96, between-image (n = 32 and between-session reliability (n = 22 to be determined. Intraclass correlation coefficients (ICCs demonstrated excellent within-image (ICCs = 0.99-1.00, P < 0.001 and very good between-image (ICCs = 0.83-0.95, P < 0.001 and between-session (ICCs = 0.89- 0.95, P < 0.001 reliability for MT, FL and PA. Between-session coefficient of variation was low (≤ 3.6% for each architectural parameter and smallest detectible difference values of 10.6%, 11.4% and 9.8% were attained for MT, FL and PA, respectively. Manually digitizing ultrasound images of the MG muscle at rest yields highly reliable measurements of its architectural properties. Furthermore, changes in MG MT, FL and PA of ≥ 10.6%, 11.4% and 9.8% respectively, as brought about by any form of intervention, should be considered meaningful.

  9. Gastrocnemius fascicle and achilles tendon length at the end of the eccentric phase in a single and multiple countermovement hop.

    Science.gov (United States)

    Lidstone, Daniel E; van Werkhoven, Herman; Needle, Alan R; Rice, Paige E; McBride, Jeffrey M

    2018-02-01

    The purpose of this investigation was to compare fascicle and tendon length of the gastrocnemius at the end of the eccentric phase during a hop utilizing a single countermovement (sCM) versus multiple countermovement (mCM1, mCM2, mCM3) strategy. Seventeen healthy males performed nine hopping trials of sCM and nine trials of mCM. Ankle and knee joint angle and lower leg length from videography and muscle ultrasound were used to calculate muscle-tendon unit (MTU), fascicle and tendon length. Sacral marker data was used to determine hopping height. Force- and displacement-time curves were utilized to calculate work. Muscle activity of the lateral and medial gastrocnemius was also measured. Fascicle length was significantly shorter (mCM3: 6.2 ± 1.5 cm, sCM: 7.3 ± 2.0 cm) and tendon length was significantly longer (mCM3: 36.5 ± 3.6 cm, sCM: 35.5 ± 3.8 cm) at the end of the eccentric phase in mCM3 in comparison to sCM. Maximal hopping height (mCM: 14.6 ± 3.1 cm, sCM: 13.1 ± 2.5 cm), eccentric phase gastrocnemius muscle activity (mCM medial gastrocnemius: 0.10 ± 0.03 mV, mCM lateral gastrocnemius: 0.08 ± 0.04 mV, sCM medial gastrocnemius: 0.07 ± 0.03 mV, sCM lateral gastrocnemius: 0.05 ± 0.04 mV), and both eccentric (mCM3: 46.6 ± 19.4 J, sCM: 38.5 ± 15.9 J) and concentric work (mCM3: 87.6 ± 26.5 J, sCM: 80.9 ± 27.6 J) were significantly higher for mCM3 compared to sCM. The results indicate that a multiple countermovement hop strategy results in shorter fascicle length and longer tendon length at the end of the eccentric phase. In addition, greater eccentric phase muscle activity during the third countermovement (mCM3) in comparison to a single countermovement hop (sCM) was observed. A multiple countermovement strategy appears to result in higher hopping height and greater work done in both the eccentric and concentric phase indicating possible contribution of stored

  10. Effects of intestinal secretagogues and distension on small bowel myoelectric activity in fasted and fed conscious dogs

    Science.gov (United States)

    da Cunha Melo, J.; Summers, R. W.; Thompson, H. H.; Wingate, D. L.; Yanda, R.

    1981-01-01

    1. Defined jejunal segments were perfused with solutions of bile salts and of ricinoleic acid during fasting and after feeding in two groups of conscious dogs, one with the segment in continuity, and the other with a Thirty-Vella loop. Myoelectric activity was recorded from chronically implanted electrodes on the jejunal segment and also from the proximal and distal in situ bowel. 2. The results in both groups were identical. During fasting, migrating complexes were present in the segment, but were replaced by intermittent spike activity during chenodeoxycholate without and with ricinoleic acid perfusion. After food, when migrating complexes were replaced by intermittent spike activity, none of the solutions produced any consistent effect. 3. In fasted animals, low levels of distension (15 mmHg) interrupted the migrating complexes in the segment and induced intermittent spike activity which was similar to that seen with the secretagogues. The migrating complexes in the main bowel continued during distension. In fed animals, spike activity increased in the segment during distension at 25 mmHg and decreased in the main bowel. In both groups, distension of the segment to pressures between 37.5 and 50 mmHg abolished spike activity both in the distended segment and the main bowel in fasted and fed states, and, in fasted dogs, migrating complexes were also abolished. 4. These results demonstrate that the inhibitory intestino-intestinal reflex is mediated through extrinsic nerves and does not require an intact myenteric plexus, whereas the altered myoelectric activity induced by secretagogues is a local effect and does not spread to adjacent bowel through either intrinsic or extrinsic neural pathways. It seems likely that the local motor effect of secretagogues is a result of net secretion, producing distension to pressures below the threshold required to activate the intestino-intestinal reflex. PMID:7338821

  11. Musculus gastrocnemius tetanus kinetics in alcohol-intoxicated rats with experimentally-induced hindlimb vascular ischemia under conditions of low-frequence muscle fatigue

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    O. A. Melnychuk

    2014-04-01

    Full Text Available Alcohol intoxication and ischemic injury of skeletal muscles often accompany each other. It is shown that patients hospitalized with chronic alcoholism develop muscle fatigue. Skeletal muscle dysfunction in alcohol-dependent patients is caused by ethanol-associated myofibrillar atrophy and metabolic disbalance, while compression-ischemic lesions result from unconsciousness of the patient, in case of taking the critical alcohol dose. Therefore, the aim of this study is to discover typical m. gastrocnemius (cap. med. tetanic kinetics changes in alcohol intoxicated rats with experimentally induced vascular ischemia of hindlimb muscles under conditions of low-frequency progressive muscle fatigue. Experiments were carried out on 10 young male Wistar rats (149.5 ± 5.8 g kept under standard vivarium conditions and diet. The investigation was conducted in two phases: chronic (30 days and acute (3 hours experiment. All surgical procedures were carried out aseptically under general anesthesia. Ishemic m. gastrocnemius (cap. med. tetanic kinetic changes and force productivity in alcohol intoxicated rats were investigated in the isometric mode, with direct electrical stimulation. The fatigue of m. gastrocnemius (cap. med. was evaluated by three characteristic criteria: the first sag effect, the secondary force rise, the second sag effect. There have been 10 similar experiments: 5 series in each study group with 10 tetanic runs in each series. The highest amplitude of the native m. gastrocnemius (cap. med. tetanus relative to isoline was taken as 100% force response. The same pattern of m. gastrocnemius (cap. med. low-frequency fatigue development was found in both rat groups under study. It is evidenced by the absence of substantial m. gastrocnemius (cap. med. tetanus kinetics differences in alcohol intoxicated rats, compared with non-alcohol intoxicated rats during fatigue test. However, the appreciable m. gastrocnemius (cap. med. tetanic force reduction

  12. Resistance training improves body composition and increases matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles of diet-induced obese rats.

    Science.gov (United States)

    Souza, Markus Vinicius Campos; Leite, Richard Diego; Souza Lino, Anderson Diogo de; Marqueti, Rita de Cássia; Bernardes, Celene Fernandes; Araújo, Heloisa Sobreiro Selistre de; Bouskela, Eliete; Bouskella, Eliete; Shiguemoto, Gilberto Eiji; Andrade Perez, Sérgio Eduardo de; Kraemer-Aguiar, Luiz Guilherme

    2014-01-01

    We investigated the influence of resistance training on body composition and matrix metalloproteinase 2 activity in skeletal muscles of rats fed a high-fat diet. Thirty-two Wistar rats were divided into four experimental groups (n = 8/each) according to diet and exercise status: Control (standard diet), Obese Control (high-fat diet), Resistance Training (standard diet) and Obese Resistance Training (high-fat diet) groups. Animals were fed a high-fat diet for 12 weeks to promote excessive weight gain. Resistance Training groups performed 12 weeks of training periods after this period in a vertical ladder three times/week. Fat percentage, fat-free mass and fat mass were assessed using dual-energy X-ray absorptiometry, and matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles was analyzed using zymography. Resistance training significantly reduced body and fat masses and fat percentages in both trained groups (pmuscles of both trained groups (pmuscle matrix metalloproteinase 2 activity promoted by excessive weight gain were positively modified by resistance training.

  13. Influence of different degrees of bilateral emulated contractures at the triceps surae on gait kinematics: The difference between gastrocnemius and soleus.

    Science.gov (United States)

    Attias, M; Bonnefoy-Mazure, A; De Coulon, G; Cheze, L; Armand, S

    2017-10-01

    Ankle plantarflexion contracture results from a permanent shortening of the muscle-tendon complex. It often leads to gait alterations. The objective of this study was to compare the kinematic adaptations of different degrees of contractures and between isolated bilateral gastrocnemius and soleus emulated contractures using an exoskeleton. Eight combinations of contractures were emulated bilaterally on 10 asymptomatic participants using an exoskeleton that was able to emulate different degrees of contracture of gastrocnemius (biarticular muscle) and soleus (monoarticular muscle), corresponding at 0°, 10°, 20°, and 30° ankle plantarflexion contracture (knee-flexed and knee-extended). Range of motion was limited by ropes attached for soleus on heel and below the knee and for gastrocnemius on heel and above the knee. A gait analysis session was performed to evaluate the effect of these different emulated contractures on the Gait Profile Score, walking speed and gait kinematics. Gastrocnemius and soleus contractures influence gait kinematics, with an increase of the Gait Profile Score. Significant differences were found in the kinematics of the ankles, knees and hips. Contractures of soleus cause a more important decrease in the range of motion at the ankle than the same degree of gastrocnemius contractures. Gastrocnemius contractures cause greater knee flexion (during the stance phase) and hip flexion (during all the gait cycle) than the same level of soleus contractures. These results can support the interpretation of the Clinical Gait Analysis data by providing a better understanding of the effect of isolate contracture of soleus and gastrocnemius on gait kinematics. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Pedicled Gastrocnemius Flap: Clinical Application in Limb Sparing Surgical Resection of Sarcoma Around the Knee Region and Popliteal Fossa

    International Nuclear Information System (INIS)

    EL-SHERBINY, M.

    2008-01-01

    To highlight on the versatility of superiorly based pedicled gastrocnemius muscle flap in the limb-sparing surgery for bone or soft tissue sarcoma around the knee and popliteal fossa. Patients and Methods: A total of 30 patients with localized bone or soft tissue sarcoma around the knee and popliteal fossa were treated with limb-salvage procedure. The study included 5 cases with bone sarcoma of the distal femur, 15 cases having bone sarcoma of proximal tibia and 10 cases having soft tissue sarcoma around the knee region and popliteal fossa. Routine preoperative staging studies were done for every patient and included local plain radiography, local MRI, isotopic bone scan and CT chest. Local MRA or angiography was done in selected cases. According to the Enneking staging system, 19 patients had stage IIB and 11 had stage IIA. Patients having bone sarcoma of the proximal tibia were subjected to wide resection, endo prosthetic reconstruction and reconstruction of the extensor mechanism by the medial gastrocnemius muscle flap. Patients having bone sarcoma of the distal femur were subjected to wide resection, endo prosthetic reconstruction and coverage of the prosthesis and re balance of the patellar tendon by the medial gas-trocnemius flap. Patients having soft tissue sarcoma were subjected to wide resection and soft tissue coverage with either medial or lateral myocutaneous gastrocnemius flap or muscle flap with grafting. Limb function was evaluated according to MSTS functional scores. Adjuvant chemotherapy or radiotherapy was given according to nationally agreed protocols. Results: There were 18 males and 12 females with a mean age of 29 years at the time of surgery (range 11-44 years). The mean follow-up period was 52 months (range 25-72 months). Resection with a negative bony and soft tissue margins could be achieved in all cases. A total of 30 flaps were used and included medial gastrocnemius muscle flaps in 21 cases (15 cases had proximal tibia endoprothesis, 5

  15. In vivo passive mechanical behaviour of muscle fascicles and tendons in human gastrocnemius muscle-tendon units.

    Science.gov (United States)

    Herbert, Robert D; Clarke, Jillian; Kwah, Li Khim; Diong, Joanna; Martin, Josh; Clarke, Elizabeth C; Bilston, Lynne E; Gandevia, Simon C

    2011-11-01

    Ultrasound imaging was used to measure the length of muscle fascicles in human gastrocnemius muscles while the muscle was passively lengthened and shortened by moving the ankle. In some subjects the muscle belly 'buckled' at short lengths. When the gastrocnemius muscle-tendon unit was passively lengthened from its shortest in vivo length by dorsiflexing the ankle, increases in muscle-tendon length were not initially accompanied by increases in muscle fascicle lengths (fascicle length remained constant), indicating muscle fascicles were slack at short muscle-tendon lengths. The muscle-tendon length at which slack is taken up differs among fascicles: some fascicles begin to lengthen at very short muscle-tendon lengths whereas other fascicles remain slack over a large range of muscle-tendon lengths. This suggests muscle fascicles are progressively 'recruited' and contribute sequentially to muscle-tendon stiffness during passive lengthening of the muscle-tendon unit. Even above their slack lengths muscle fascicles contribute only a small part (tendon length. The contribution of muscle fascicles to muscle-tendon length increases with muscle length. The novelty of this work is that it reveals a previously unrecognised phenomenon (buckling at short lengths), posits a new mechanism of passive mechanical properties of muscle (recruitment of muscle fascicles), and confirms with high-resolution measurements that the passive compliance of human gastrocnemius muscle-tendon units is due largely to the tendon. It would be interesting to investigate if adaptations of passive properties of muscles are associated with changes in the distribution of muscle lengths at which fascicles fall slack.

  16. Three-Dimensional Muscle Architecture and Comprehensive Dynamic Properties of Rabbit Gastrocnemius, Plantaris and Soleus: Input for Simulation Studies

    Science.gov (United States)

    Siebert, Tobias; Leichsenring, Kay; Rode, Christian; Wick, Carolin; Stutzig, Norman; Schubert, Harald; Blickhan, Reinhard; Böl, Markus

    2015-01-01

    The vastly increasing number of neuro-muscular simulation studies (with increasing numbers of muscles used per simulation) is in sharp contrast to a narrow database of necessary muscle parameters. Simulation results depend heavily on rough parameter estimates often obtained by scaling of one muscle parameter set. However, in vivo muscles differ in their individual properties and architecture. Here we provide a comprehensive dataset of dynamic (n = 6 per muscle) and geometric (three-dimensional architecture, n = 3 per muscle) muscle properties of the rabbit calf muscles gastrocnemius, plantaris, and soleus. For completeness we provide the dynamic muscle properties for further important shank muscles (flexor digitorum longus, extensor digitorum longus, and tibialis anterior; n = 1 per muscle). Maximum shortening velocity (normalized to optimal fiber length) of the gastrocnemius is about twice that of soleus, while plantaris showed an intermediate value. The force-velocity relation is similar for gastrocnemius and plantaris but is much more bent for the soleus. Although the muscles vary greatly in their three-dimensional architecture their mean pennation angle and normalized force-length relationships are almost similar. Forces of the muscles were enhanced in the isometric phase following stretching and were depressed following shortening compared to the corresponding isometric forces. While the enhancement was independent of the ramp velocity, the depression was inversely related to the ramp velocity. The lowest effect strength for soleus supports the idea that these effects adapt to muscle function. The careful acquisition of typical dynamical parameters (e.g. force-length and force-velocity relations, force elongation relations of passive components), enhancement and depression effects, and 3D muscle architecture of calf muscles provides valuable comprehensive datasets for e.g. simulations with neuro-muscular models, development of more realistic muscle models, or

  17. Three-Dimensional Muscle Architecture and Comprehensive Dynamic Properties of Rabbit Gastrocnemius, Plantaris and Soleus: Input for Simulation Studies.

    Directory of Open Access Journals (Sweden)

    Tobias Siebert

    Full Text Available The vastly increasing number of neuro-muscular simulation studies (with increasing numbers of muscles used per simulation is in sharp contrast to a narrow database of necessary muscle parameters. Simulation results depend heavily on rough parameter estimates often obtained by scaling of one muscle parameter set. However, in vivo muscles differ in their individual properties and architecture. Here we provide a comprehensive dataset of dynamic (n = 6 per muscle and geometric (three-dimensional architecture, n = 3 per muscle muscle properties of the rabbit calf muscles gastrocnemius, plantaris, and soleus. For completeness we provide the dynamic muscle properties for further important shank muscles (flexor digitorum longus, extensor digitorum longus, and tibialis anterior; n = 1 per muscle. Maximum shortening velocity (normalized to optimal fiber length of the gastrocnemius is about twice that of soleus, while plantaris showed an intermediate value. The force-velocity relation is similar for gastrocnemius and plantaris but is much more bent for the soleus. Although the muscles vary greatly in their three-dimensional architecture their mean pennation angle and normalized force-length relationships are almost similar. Forces of the muscles were enhanced in the isometric phase following stretching and were depressed following shortening compared to the corresponding isometric forces. While the enhancement was independent of the ramp velocity, the depression was inversely related to the ramp velocity. The lowest effect strength for soleus supports the idea that these effects adapt to muscle function. The careful acquisition of typical dynamical parameters (e.g. force-length and force-velocity relations, force elongation relations of passive components, enhancement and depression effects, and 3D muscle architecture of calf muscles provides valuable comprehensive datasets for e.g. simulations with neuro-muscular models, development of more realistic

  18. Diethyl hexyl phthalate-induced changes in insulin signaling molecules and the protective role of antioxidant vitamins in gastrocnemius muscle of adult male rat

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, Chinnapaiyan; Khan, Adam Ismail; Balaji, Venkataraman; Selvaraj, Jayaraman; Balasubramanian, Karundevi, E-mail: kbala82@rediffmail.com

    2011-12-15

    Diethyl hexyl phthalate (DEHP) is an endocrine disruptor, it influences various organ systems in human beings and experimental animals. DEHP reduced the serum testosterone and increased the blood glucose, estradiol, T{sub 3} and T{sub 4} in rats. However, the effect of DEHP on insulin signaling and glucose oxidation in skeletal muscle is not known. Adult male albino rats were divided into four groups: Group I: Control; Groups II and III: DEHP treated (dissolved in olive oil at a dose of 10 and 100 mg/kg body weight, respectively, once daily through gastric intubation for 30 days); and Group IV: DEHP (100 mg/kg body weight) plus vitamins E (50 mg/kg body weight) and C (100 mg/kg body weight) dissolved in olive oil and distilled water, respectively, once daily through gastric intubation for 30 days. On completion of treatment, animals were euthanized and perfused (whole body); gastrocnemius muscle was dissected out and subjected to assessment of various parameters. DEHP treatment increased the H{sub 2}O{sub 2}, hydroxyl radical levels and lipid peroxidation which disrupt the membrane integrity and insulin receptor. DEHP impaired the insulin signal transduction, glucose uptake and oxidation through decreased expression of plasma membrane GLUT4, which may partly be responsible for the elevation of fasting blood glucose level. The present study suggests that DEHP exposure affects glucose oxidation in skeletal muscle and is mediated through enhanced lipid peroxidation, impaired insulin signaling and GLUT4 expression in plasma membrane. Antioxidant vitamins (C and E) have a protective role against the adverse effect of DEHP. -- Highlights: Black-Right-Pointing-Pointer DEHP treatment significantly decreased serum insulin and testosterone levels. Black-Right-Pointing-Pointer Increased ROS and decreased glucose uptake were observed in DEHP treated animals. Black-Right-Pointing-Pointer Impaired insulin signaling in gastrocnemius muscle was observed in DEHP treatment. Black

  19. Immediate and Short-Term Effects of Upper Thoracic Manipulation on Myoelectric Activity of Sternocleidomastoid Muscles in Young Women With Chronic Neck Pain: A Randomized Blind Clinical Trial.

    Science.gov (United States)

    Pires, Paulo Fernandes; Packer, Amanda Carine; Dibai-Filho, Almir Vieira; Rodrigues-Bigaton, Delaine

    2015-10-01

    The aim of this study was to assess the immediate and short-term effects of upper thoracic spine manipulation on pain intensity and myoelectric activity of the sternocleidomastoid muscles in young women with chronic neck pain. A randomized clinical trial was carried out involving 32 women with chronic neck pain (mean age, 24.8 ± 5.4 years) allocated to an experimental group and a placebo group. Three evaluations were carried out: baseline, immediate postintervention, and short-term postintervention (48-72 hours after intervention). Myoelectric activity of the right and left sternocleidomastoid muscles was assessed at rest and during isometric contractions for cervical flexion and elevation of the shoulder girdle. Neck pain intensity was assessed at rest using a visual analog scale. Comparisons of the data were performed using 2-way repeated-measures analysis of variance with the Bonferroni correction. The level of significance was set at P 0.40). No statistically significant differences were found for any of the variables analyzed in the intergroup comparisons at the different evaluation times (P > .05). No statistically significant differences were found in the intragroup or intergroup analyses of the experimental and placebo groups regarding myoelectric activity of the cervical muscles or the intensity of neck pain at rest in the immediate or short-term postintervention evaluations. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  20. Nonlinear analysis of electromyogram following gait training with myoelectrically triggered neuromuscular electrical stimulation in stroke survivors

    Science.gov (United States)

    Dutta, Anirban; Khattar, Bhawna; Banerjee, Alakananda

    2012-12-01

    Neuromuscular electrical stimulation (NMES) facilitates ambulatory function after paralysis by activating the muscles of the lower extremities. The NMES-assisted stepping can either be triggered by a heel-switch (switch-trigger), or by an electromyogram (EMG)-based gait event detector (EMG-trigger). The command sources—switch-trigger or EMG-trigger—were presented to each group of six chronic (>6 months post-stroke) hemiplegic stroke survivors. The switch-trigger group underwent transcutaneous NMES-assisted gait training for 1 h, five times a week for 2 weeks, where the stimulation of the tibialis anterior muscle of the paretic limb was triggered with a heel-switch detecting heel-rise of the same limb. The EMG-trigger group underwent transcutaneous NMES-assisted gait training of the same duration and frequency where the stimulation was triggered with surface EMG from medial gastrocnemius (MG) of the paretic limb in conjunction with a heel-switch detecting heel-rise of the same limb. During the baseline and post-intervention surface EMG assessment, a total of 10 s of surface EMG was recorded from bilateral MG muscle while the subjects tried to stand steady on their toes. A nonlinear tool—recurrence quantification analysis (RQA)—was used to analyze the surface EMG. The objective of this study was to find the effect of NMES-assisted gait training with switch-trigger or EMG-trigger on two RQA parameters—the percentage of recurrence (%Rec) and determinism (%Det), which were extracted from surface EMG during fatiguing contractions of the paretic muscle. The experimental results showed that during fatiguing contractions, (1) %Rec and %Det have a higher initial value for paretic muscle than the non-paretic muscle, (2) the rate of change in %Rec and %Det was negative for the paretic muscle but positive for the non-paretic muscle, (3) the rate of change in %Rec and %Det significantly increased from baseline for the paretic muscle after EMG-triggered NMES

  1. Learning an EMG Controlled Game : Task-Specific Adaptations and Transfer

    NARCIS (Netherlands)

    van Dijk, Ludger; van der Sluis, Corry K.; van Dijk, Hylke W.; Bongers, Raoul M.

    2016-01-01

    Video games that aim to improve myoelectric control (myogames) are gaining popularity and are often part of the rehabilitation process following an upper limb amputation. However, direct evidence for their effect on prosthetic skill is limited. This study aimed to determine whether and how myogaming

  2. Botulinum Neurotoxin A Injections Influence Stretching of the Gastrocnemius Muscle-Tendon Unit in an Animal Model

    Directory of Open Access Journals (Sweden)

    Christopher J. Tuohy

    2012-08-01

    Full Text Available Botulinum Neurotoxin A (BoNT-A injections have been used for the treatment of muscle contractures and spasticity. This study assessed the influence of (BoNT-A injections on passive biomechanical properties of the muscle-tendon unit. Mouse gastrocnemius muscle (GC was injected with BoNT-A (n = 18 or normal saline (n = 18 and passive, non-destructive, in vivo load relaxation experimentation was performed to examine how the muscle-tendon unit behaves after chemical denervation with BoNT-A. Injection of BoNT-A impaired passive muscle recovery (15% vs. 35% recovery to pre-stretching baseline, p < 0.05 and decreased GC stiffness (0.531 ± 0.061 N/mm vs. 0.780 ± 0.037 N/mm, p < 0.05 compared to saline controls. The successful use of BoNT-A injections as an adjunct to physical therapy may be in part attributed to the disruption of the stretch reflex; thereby modulating in vivo passive muscle properties. However, it is also possible that BoNT-A injection may alter the structure of skeletal muscle; thus modulating the in vivo passive biomechanical properties of the muscle-tendon unit.

  3. Adaptation to random and systematic errors: Comparison of amputee and non-amputee control interfaces with varying levels of process noise

    Science.gov (United States)

    Kording, Konrad P.; Hargrove, Levi J.; Sensinger, Jonathon W.

    2017-01-01

    The objective of this study was to understand how people adapt to errors when using a myoelectric control interface. We compared adaptation across 1) non-amputee subjects using joint angle, joint torque, and myoelectric control interfaces, and 2) amputee subjects using myoelectric control interfaces with residual and intact limbs (five total control interface conditions). We measured trial-by-trial adaptation to self-generated errors and random perturbations during a virtual, single degree-of-freedom task with two levels of feedback uncertainty, and evaluated adaptation by fitting a hierarchical Kalman filter model. We have two main results. First, adaptation to random perturbations was similar across all control interfaces, whereas adaptation to self-generated errors differed. These patterns matched predictions of our model, which was fit to each control interface by changing the process noise parameter that represented system variability. Second, in amputee subjects, we found similar adaptation rates and error levels between residual and intact limbs. These results link prosthesis control to broader areas of motor learning and adaptation and provide a useful model of adaptation with myoelectric control. The model of adaptation will help us understand and solve prosthesis control challenges, such as providing additional sensory feedback. PMID:28301512

  4. Adaptation to random and systematic errors: Comparison of amputee and non-amputee control interfaces with varying levels of process noise.

    Directory of Open Access Journals (Sweden)

    Reva E Johnson

    Full Text Available The objective of this study was to understand how people adapt to errors when using a myoelectric control interface. We compared adaptation across 1 non-amputee subjects using joint angle, joint torque, and myoelectric control interfaces, and 2 amputee subjects using myoelectric control interfaces with residual and intact limbs (five total control interface conditions. We measured trial-by-trial adaptation to self-generated errors and random perturbations during a virtual, single degree-of-freedom task with two levels of feedback uncertainty, and evaluated adaptation by fitting a hierarchical Kalman filter model. We have two main results. First, adaptation to random perturbations was similar across all control interfaces, whereas adaptation to self-generated errors differed. These patterns matched predictions of our model, which was fit to each control interface by changing the process noise parameter that represented system variability. Second, in amputee subjects, we found similar adaptation rates and error levels between residual and intact limbs. These results link prosthesis control to broader areas of motor learning and adaptation and provide a useful model of adaptation with myoelectric control. The model of adaptation will help us understand and solve prosthesis control challenges, such as providing additional sensory feedback.

  5. Adaptation to random and systematic errors: Comparison of amputee and non-amputee control interfaces with varying levels of process noise.

    Science.gov (United States)

    Johnson, Reva E; Kording, Konrad P; Hargrove, Levi J; Sensinger, Jonathon W

    2017-01-01

    The objective of this study was to understand how people adapt to errors when using a myoelectric control interface. We compared adaptation across 1) non-amputee subjects using joint angle, joint torque, and myoelectric control interfaces, and 2) amputee subjects using myoelectric control interfaces with residual and intact limbs (five total control interface conditions). We measured trial-by-trial adaptation to self-generated errors and random perturbations during a virtual, single degree-of-freedom task with two levels of feedback uncertainty, and evaluated adaptation by fitting a hierarchical Kalman filter model. We have two main results. First, adaptation to random perturbations was similar across all control interfaces, whereas adaptation to self-generated errors differed. These patterns matched predictions of our model, which was fit to each control interface by changing the process noise parameter that represented system variability. Second, in amputee subjects, we found similar adaptation rates and error levels between residual and intact limbs. These results link prosthesis control to broader areas of motor learning and adaptation and provide a useful model of adaptation with myoelectric control. The model of adaptation will help us understand and solve prosthesis control challenges, such as providing additional sensory feedback.

  6. Correlations and coherence of monopolar EMG-currents of the medial gastrocnemius muscle in proximal and distal compartments

    Directory of Open Access Journals (Sweden)

    Vinzenz eVon Tscharner

    2014-06-01

    Full Text Available The penniform gastrocnemius muscle contains multiple heads in the proximal regions and the aponeuroses are attached to the Achilles tendon. The multiple head structure lead to the assumption that different regions of the muscle must be activated compartment wise. The purpose of this study was to compare the correlation and coherence of EMG-currents within and between proximal and distal compartments of the medial gastrocnemius muscle, which reflect underling synchronization of motor units. It was hypothesized and shown that phase-inverted signals represent a property that discriminates compartments. However, the phase-inverted and non-inverted signals showed values of correlations that were indicative for highly synchronized signals. The correlation increased with the complexity of the task and was higher for the calf-rising movement than while balancing in a tiptoe position. Because the muscle fibers do not span the whole length of the muscles one has to conclude that the MUs were synchronized by synchronizing the various motor nerves. This study shows that it is essential to measure monopolar signals and use non-isometric contractions to observe synchronization of the EMG-signals. One could speculate that compartmental differences can only be observed if more complex movements that generate rotational forces at the knee or ankle are used.

  7. The pediculated gastrocnemius muscle flap as a treatment for soft tissue problems of the knee – indication, placement and results

    Directory of Open Access Journals (Sweden)

    Moebius, Boris

    2012-01-01

    Full Text Available With the increase of endoprosthetic knee replacements, there is also an increase of critical wounds to the knee due to a high incidence of soft tissue problems (ranging from wound healing defects to severe wound infections. The literature describes a general rate of soft tissue complications of up to 20% [1], [2], with 5% [3] involving exposed bone. These complications are an increasingly important problem for surgeons. Since sufficient coverage of bones, tendons and prosthetic material with soft tissue is a necessity, the use of a pediculated muscle flap is the only solution in some cases. The gastrocnemius muscle is very useful for this purpose. It is an elaborate procedure which is associated with a high rate of complications. However, this procedure can establish a secure coverage with soft tissue, and the function of the prosthesis and the patient’s extremity can be saved. We have treated 23 patients with a gastrocnemius rotation flap after knee prosthesis or knee arthrodesis infection with consecutive soft tissue damage at our hospital from 8/2004 through 3/2011. The overall rate of healing of the knee infections with stable soft tissue status is almost 87%. The revision rate with lifting of the flap and revision of the sutures at the point of insertion as well as the point of extraction was about 35% with long-term conservative or additional surgical treatments.

  8. Neural-Network Control Of Prosthetic And Robotic Hands

    Science.gov (United States)

    Buckley, Theresa M.

    1991-01-01

    Electronic neural networks proposed for use in controlling robotic and prosthetic hands and exoskeletal or glovelike electromechanical devices aiding intact but nonfunctional hands. Specific to patient, who activates grasping motion by voice command, by mechanical switch, or by myoelectric impulse. Patient retains higher-level control, while lower-level control provided by neural network analogous to that of miniature brain. During training, patient teaches miniature brain to perform specialized, anthropomorphic movements unique to himself or herself.

  9. Application of support vector machines in detecting hand grasp gestures using a commercially off the shelf wireless myoelectric armband.

    Science.gov (United States)

    Amirabdollahian, Farshid; Walters, Michael L

    2017-07-01

    The propose of this study was to assess the feasibility of using support vector machines in analysing myoelectric signals acquired using an off the shelf device, the Myo armband from Thalmic Lab, when performing hand grasp gestures. Participants (n = 26) took part in the study wearing the armband and producing a series of required gestures. Support vector machines were used to train a model using participant training values, and to classify gestures produced by the same participants. Different Kernel functions and electrode combinations were studied. Also we contrasted different lengths of training values versus different lengths for the classification samples. The overall accuracy was 94.9% with data from 8 electrodes, and 72% where only four of the electrodes were used. The linear kernel outperformed the polynomial, and radial basis function. Exploring the number of training samples versus the achieved classification accuracy, results identified acceptable accuracies (> 90%) for training around 2.5s, and recognising grasp with 0.2s of acquired data. The best recognised grasp was the hand closed (97.6%), followed by cylindrical grasp (96.8%), the lateral grasp (93.2%) and tripod (92%). These results allows us to progress to the next stage of work where the Myo armband is used in the context of robot-mediated stroke rehabilitation and also involves more dynamic interactions as well as gross upper arm movements.

  10. Insulin Resistance Is Not Associated with an Impaired Mitochondrial Function in Contracting Gastrocnemius Muscle of Goto-Kakizaki Diabetic Rats In Vivo.

    Directory of Open Access Journals (Sweden)

    Michael Macia

    Full Text Available Insulin resistance, altered lipid metabolism and mitochondrial dysfunction in skeletal muscle would play a major role in type 2 diabetes mellitus (T2DM development, but the causal relationships between these events remain conflicting. To clarify this issue, gastrocnemius muscle function and energetics were investigated throughout a multidisciplinary approach combining in vivo and in vitro measurements in Goto-Kakizaki (GK rats, a non-obese T2DM model developing peripheral insulin resistant without abnormal level of plasma non-esterified fatty acids (NEFA. Wistar rats were used as controls. Mechanical performance and energy metabolism were assessed strictly non-invasively using magnetic resonance (MR imaging and 31-phosphorus MR spectroscopy (31P-MRS. Compared with control group, plasma insulin and glucose were respectively lower and higher in GK rats, but plasma NEFA level was normal. In resting GK muscle, phosphocreatine content was reduced whereas glucose content and intracellular pH were both higher. However, there were not differences between both groups for basal oxidative ATP synthesis rate, citrate synthase activity, and intramyocellular contents for lipids, glycogen, ATP and ADP (an important in vivo mitochondrial regulator. During a standardized fatiguing protocol (6 min of maximal repeated isometric contractions electrically induced at a frequency of 1.7 Hz, mechanical performance and glycolytic ATP production rate were reduced in diabetic animals whereas oxidative ATP production rate, maximal mitochondrial capacity and ATP cost of contraction were not changed. These findings provide in vivo evidence that insulin resistance is not caused by an impairment of mitochondrial function in this diabetic model.

  11. In vivo relationship between pelvis motion and deep fascia displacement of the medial gastrocnemius: anatomical and functional implications.

    Science.gov (United States)

    Cruz-Montecinos, Carlos; González Blanche, Alberto; López Sánchez, David; Cerda, Mauricio; Sanzana-Cuche, Rodolfo; Cuesta-Vargas, Antonio

    2015-11-01

    Different authors have modelled myofascial tissue connectivity over a distance using cadaveric models, but in vivo models are scarce. The aim of this study was to evaluate the relationship between pelvic motion and deep fascia displacement in the medial gastrocnemius (MG). Deep fascia displacement of the MG was evaluated through automatic tracking with an ultrasound. Angular variation of the pelvis was determined by 2D kinematic analysis. The average maximum fascia displacement and pelvic motion were 1.501 ± 0.78 mm and 6.55 ± 2.47 °, respectively. The result of a simple linear regression between fascia displacement and pelvic motion for three task executions by 17 individuals was r = 0.791 (P fascia displacement of the MG (r = 0.449, P fasciae in restricting movement in remote zones. © 2015 Anatomical Society.

  12. Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats

    Energy Technology Data Exchange (ETDEWEB)

    Carnevali, L.C. Jr. [Grupo de Biologia Molecular da Célula, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo SP (Brazil); Centro Universitário Ítalo-Brasileiro (Unítalo), São Paulo SP (Brazil); Eder, R.; Lira, F.S. [Grupo de Biologia Molecular da Célula, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo SP (Brazil); Lima, W.P. [Grupo de Biologia Molecular da Célula, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo SP (Brazil); Instituto Federal de Educação,Ciência e Tecnologia de São Paulo, São Paulo SP (Brazil); Gonçalves, D.C. [Grupo de Biologia Molecular da Célula, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo SP (Brazil); Zanchi, N.E. [Laboratorio de Nutrição e Metabolismo Aplicado à Atividade Motora, Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo SP (Brazil); Centro de Pesquisa do Genoma Humano, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo SP (Brazil); Nicastro, H. [Laboratorio de Nutrição e Metabolismo Aplicado à Atividade Motora, Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo SP (Brazil); Lavoie, J.M. [Department of Kinesiology, University of Montreal, Montreal (Canada); Seelaender, M.C.L. [Grupo de Biologia Molecular da Célula, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo SP (Brazil)

    2012-06-29

    We examined the capacity of high-intensity intermittent training (HI-IT) to facilitate the delivery of lipids to enzymes responsible for oxidation, a task performed by the carnitine palmitoyl transferase (CPT) system in the rat gastrocnemius muscle. Male adult Wistar rats (160-250 g) were randomly distributed into 3 groups: sedentary (Sed, N = 5), HI-IT (N = 10), and moderate-intensity continuous training (MI-CT, N = 10). The trained groups were exercised for 8 weeks with a 10% (HI-IT) and a 5% (MI-CT) overload. The HI-IT group presented 11.8% decreased weight gain compared to the Sed group. The maximal activities of CPT-I, CPT-II, and citrate synthase were all increased in the HI-IT group compared to the Sed group (P < 0.01), as also was gene expression, measured by RT-PCR, of fatty acid binding protein (FABP; P < 0.01) and lipoprotein lipase (LPL; P < 0.05). Lactate dehydrogenase also presented a higher maximal activity (nmol·min{sup −1}·mg protein{sup −1}) in HI-IT (around 83%). We suggest that 8 weeks of HI-IT enhance mitochondrial lipid transport capacity thus facilitating the oxidation process in the gastrocnemius muscle. This adaptation may also be associated with the decrease in weight gain observed in the animals and was concomitant to a higher gene expression of both FABP and LPL in HI-IT, suggesting that intermittent exercise is a “time-efficient” strategy inducing metabolic adaptation.

  13. Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats

    International Nuclear Information System (INIS)

    Carnevali, L.C. Jr.; Eder, R.; Lira, F.S.; Lima, W.P.; Gonçalves, D.C.; Zanchi, N.E.; Nicastro, H.; Lavoie, J.M.; Seelaender, M.C.L.

    2012-01-01

    We examined the capacity of high-intensity intermittent training (HI-IT) to facilitate the delivery of lipids to enzymes responsible for oxidation, a task performed by the carnitine palmitoyl transferase (CPT) system in the rat gastrocnemius muscle. Male adult Wistar rats (160-250 g) were randomly distributed into 3 groups: sedentary (Sed, N = 5), HI-IT (N = 10), and moderate-intensity continuous training (MI-CT, N = 10). The trained groups were exercised for 8 weeks with a 10% (HI-IT) and a 5% (MI-CT) overload. The HI-IT group presented 11.8% decreased weight gain compared to the Sed group. The maximal activities of CPT-I, CPT-II, and citrate synthase were all increased in the HI-IT group compared to the Sed group (P < 0.01), as also was gene expression, measured by RT-PCR, of fatty acid binding protein (FABP; P < 0.01) and lipoprotein lipase (LPL; P < 0.05). Lactate dehydrogenase also presented a higher maximal activity (nmol·min −1 ·mg protein −1 ) in HI-IT (around 83%). We suggest that 8 weeks of HI-IT enhance mitochondrial lipid transport capacity thus facilitating the oxidation process in the gastrocnemius muscle. This adaptation may also be associated with the decrease in weight gain observed in the animals and was concomitant to a higher gene expression of both FABP and LPL in HI-IT, suggesting that intermittent exercise is a “time-efficient” strategy inducing metabolic adaptation

  14. Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats

    Directory of Open Access Journals (Sweden)

    L.C. Carnevali Jr

    2012-08-01

    Full Text Available We examined the capacity of high-intensity intermittent training (HI-IT to facilitate the delivery of lipids to enzymes responsible for oxidation, a task performed by the carnitine palmitoyl transferase (CPT system in the rat gastrocnemius muscle. Male adult Wistar rats (160-250 g were randomly distributed into 3 groups: sedentary (Sed, N = 5, HI-IT (N = 10, and moderate-intensity continuous training (MI-CT, N = 10. The trained groups were exercised for 8 weeks with a 10% (HI-IT and a 5% (MI-CT overload. The HI-IT group presented 11.8% decreased weight gain compared to the Sed group. The maximal activities of CPT-I, CPT-II, and citrate synthase were all increased in the HI-IT group compared to the Sed group (P < 0.01, as also was gene expression, measured by RT-PCR, of fatty acid binding protein (FABP; P < 0.01 and lipoprotein lipase (LPL; P < 0.05. Lactate dehydrogenase also presented a higher maximal activity (nmol·min-1·mg protein-1 in HI-IT (around 83%. We suggest that 8 weeks of HI-IT enhance mitochondrial lipid transport capacity thus facilitating the oxidation process in the gastrocnemius muscle. This adaptation may also be associated with the decrease in weight gain observed in the animals and was concomitant to a higher gene expression of both FABP and LPL in HI-IT, suggesting that intermittent exercise is a "time-efficient" strategy inducing metabolic adaptation.

  15. Effects of 2 weeks lower limb immobilization and two separate rehabilitation regimens on gastrocnemius muscle protein turnover signaling and normalization genes

    DEFF Research Database (Denmark)

    Nedergaard, Anders; Jespersen, Jakob G; Pingel, Jessica

    2012-01-01

    of resistance training and continued protein/carbohydrate supplementation (Study 2). We obtained muscle biopsies from the medial gastrocnemius prior to immobilization (PRE), post-immobilization (IMMO) and post-rehabilitation (REHAB) and measured protein expression and phosphorylation of Akt, mTOR, S6k, 4E-BP1...

  16. Temporal changes in ERK phosphorylation are harmonious with 4E-BP1, but not p70S6K, during clenbuterol-induced hypertrophy in the rat gastrocnemius.

    Science.gov (United States)

    Sumi, Koichiro; Higashi, Seiichiro; Natsume, Midori; Kawahata, Keiko; Nakazato, Koichi

    2014-08-01

    Extracellular signal-regulated kinase (ERK) is required for clenbuterol (CB)-dependent fast-type myofibril enlargement; however, its contribution to translation control is unclear. ERK mediates translational regulation through mammalian target of rapamycin complex 1 (mTORC1) activation and (or) mTORC1-independent pathways. In this study, we aimed to investigate the role of ERK in translational control during CB-induced muscular hypertrophy by measuring time-dependent changes in the phosphorylation statuses of ERK, p70 ribosomal S6 kinase (p70S6K; an indicator of mTORC1 activity), 4E-binding protein 1 (4E-BP1), eukaryotic elongation factor 2 (eEF2), and other related signaling molecules in rat gastrocnemius muscles. Five-day administration of CB induced phenotypes associated with muscular hypertrophy (significant increases in wet weight and isometric ankle flexion torque in the gastrocnemius muscle), but was not accompanied by elevated ERK or p70S6K phosphorylation. One-day administration of CB caused significant increases in the phosphorylation of ERK, p70S6K, and 4E-BP1. In contrast, 3-day administration of CB caused significant increases in the phosphorylation of ERK and 4E-BP1, but not p70S6K. In addition, positive correlations were observed between ERK and 4E-BP1 on days 1 and 3, whereas a correlation between ERK and p70S6K was only observed on day 1. eEF2 phosphorylation was unchanged on both days 1 and 3. These findings suggest that ERK accelerates the initiation of translation, but does not support the involvement of ERK in translational elongation. Furthermore, ERK may play a major role in promoting translational initiation by mediating the phosphorylation of 4E-BP1, and may contribute to the initial activation of mTORC1 during CB administration.

  17. Intestinal myoelectric activity and contractile motility in dogs with a reversed jejunal segment after extensive small bowel resection.

    Science.gov (United States)

    Uchiyama, M; Iwafuchi, M; Ohsawa, Y; Yagi, M; Iinuma, Y; Ohtani, S

    1992-06-01

    To evaluate the functioning and effectiveness of a reversed jejunal segment after extensive small bowel resection, we continuously measured the postoperative bowel motility (using bipolar electrodes and/or contractile strain gage force transducers) in interdigestive and postprandial conscious dogs at 2 to 5 weeks after surgery. The fasting duodenal migrating myoelectric (or motor) complex (MMC) occurred at markedly longer intervals in dogs with a 20-cm reversed jejunal segment created after 75% to 80% extensive small bowel resection (group 3) than in dogs that received extensive resection alone (group 2) or dogs that underwent construction of a reversed jejunal segment without bowel resection (group 1). The MMC arising from the duodenum was often interrupted at the jejunum above the proximal anastomosis and did not migrate smoothly to the reversed segment or terminal ileum in group 3. In addition, brief small discordant contractions were frequent in the reversed segment and the jejunum above the proximal anastomosis in group 3. The duration of the postprandial period without duodenal MMC activity was significantly prolonged in groups 2 and 3. These results suggest that the transit time and passage of intestinal contents were delayed and that the periodical MMC was disturbed in group 3. The delay of transit time was due to prolongation of the interval between duodenal MMCs, the interruption of MMC propagation at the jejunum above the proximal anastomosis, the dominance of MMCs that followed the inherent anatomical continuity of the bowel, and discordant movements across the proximal anastomosis. Functional obstruction could be a potential problem in a 20-cm reversed jejunal segment inserted after extensive small bowel resection.

  18. Experimental Study of Real-Time Classification of 17 Voluntary Movements for Multi-Degree Myoelectric Prosthetic Hand

    Directory of Open Access Journals (Sweden)

    Trongmun Jiralerspong

    2017-11-01

    Full Text Available The myoelectric prosthetic hand is a powerful tool developed to help people with upper limb loss restore the functions of a biological hand. Recognizing multiple hand motions from only a few electromyography (EMG sensors is one of the requirements for the development of prosthetic hands with high level of usability. This task is highly challenging because both classification rate and misclassification rate worsen with additional hand motions. This paper presents a signal processing technique that uses spectral features and an artificial neural network to classify 17 voluntary movements from EMG signals. The main highlight will be on the use of a small set of low-cost EMG sensor for classification of a reasonably large number of hand movements. The aim of this work is to extend the capabilities to recognize and produce multiple movements beyond what is currently feasible. This work will also show and discuss about how tailoring the number of hand motions for a specific task can help develop a more reliable prosthetic hand system. Online classification experiments have been conducted on seven male and five female participants to evaluate the validity of the proposed method. The proposed algorithm achieves an overall correct classification rate of up to 83%, thus, demonstrating the potential to classify 17 movements from 6 EMG sensors. Furthermore, classifying 9 motions using this method could achieve an accuracy of up to 92%. These results show that if the prosthetic hand is intended for a specific task, limiting the number of motions can significantly increase the performance and usability.

  19. Hip orthosis powered by pneumatic artificial muscle: voluntary activation in absence of myoelectrical signal.

    Science.gov (United States)

    do Nascimento, Breno Gontijo; Vimieiro, Claysson Bruno Santos; Nagem, Danilo Alves Pinto; Pinotti, Marcos

    2008-04-01

    Powered orthosis is a special class of gait assist device that employs a mechanical or electromechanical actuator to enhance movement of hip, knee, or ankle articulations. Pneumatic artificial muscle (PAM) has been suggested as a pneumatic actuator because its performance is similar to biological muscle. The electromyography (EMG) signal interpretation is the most popular and simplest method to establish the patient voluntary control of the orthosis. However, this technique is not suitable for patients presenting neurological lesions causing absence or very low quality of EMG signal. For those cases, an alternative control strategy should be provided. The aim of the present study is to develop a gait assistance orthosis for lower limb powered by PAMs controlled by a voluntary activation method based on the angular behavior of hip joint. In the present study, an orthosis that has been molded in a patient was employed and, by taking her anthropometric parameters and movement constraints, the adaptation of the existing orthosis to the powered orthosis was planned. A control system was devised allowing voluntary control of a powered orthosis suitable for patients presenting neurological lesions causing absence or very low quality of EMG signal. A pilot clinical study was reported where a patient, victim of poliovirus, successfully tested a hip orthosis especially modified for the gait test evaluation in the parallel bar system. The hip orthosis design and the control circuitry parameters were able to be set to provide satisfactory and comfortable use of the orthosis during the gait cycle.

  20. Non-weight-bearing neural control of a powered transfemoral prosthesis.

    Science.gov (United States)

    Hargrove, Levi J; Simon, Ann M; Lipschutz, Robert; Finucane, Suzanne B; Kuiken, Todd A

    2013-06-19

    Lower limb prostheses have traditionally been mechanically passive devices without electronic control systems. Microprocessor-controlled passive and powered devices have recently received much interest from the clinical and research communities. The control systems for these devices typically use finite-state controllers to interpret data measured from mechanical sensors embedded within the prosthesis. In this paper we investigated a control system that relied on information extracted from myoelectric signals to control a lower limb prosthesis while amputee patients were seated. Sagittal plane motions of the knee and ankle can be accurately (>90%) recognized and controlled in both a virtual environment and on an actuated transfemoral prosthesis using only myoelectric signals measured from nine residual thigh muscles. Patients also demonstrated accurate (~90%) control of both the femoral and tibial rotation degrees of freedom within the virtual environment. A channel subset investigation was completed and the results showed that only five residual thigh muscles are required to achieve accurate control. This research is the first step in our long-term goal of implementing myoelectric control of lower limb prostheses during both weight-bearing and non-weight-bearing activities for individuals with transfemoral amputation.

  1. Effect of angular velocity on soleus and medial gastrocnemius H-reflex during maximal concentric and eccentric muscle contraction.

    Science.gov (United States)

    Duclay, Julien; Robbe, Alice; Pousson, Michel; Martin, Alain

    2009-10-01

    At rest, the H-reflex is lower during lengthening than shortening actions. During passive lengthening, both soleus (SOL) and medial gastrocnemius (MG) H-reflex amplitudes decrease with increasing angular velocity. This study was designed to investigate whether H-reflex amplitude is affected by angular velocity during concentric and eccentric maximal voluntary contraction (MVC). Experiments were performed on nine healthy men. At a constant angular velocity of 60 degrees /s and 20 degrees /s, maximal H-reflex and M-wave potentials were evoked at rest (i.e., H(max) and M(max), respectively) and during concentric and eccentric MVC (i.e., H(sup) and M(sup), respectively). Regardless of the muscle, H(max)/M(max) was lower during lengthening than shortening actions and the H(sup)/M(sup) ratio was higher than H(max)/M(max) during lengthening actions. Whereas no action type and angular velocity effects on the MG H(sup)/M(sup) were found, the SOL H(sup)/M(sup) was lower during eccentric than concentric MVC and this depression was increased with higher angular velocity. Our findings indicate that the depression of the H-reflex amplitude during eccentric compared to concentric MVC depends mainly on the amount of inhibition induced by lengthening action. In conclusion, H-reflex should be evoked during both passive and active dynamic trials to evaluate the plasticity of the spinal loop.

  2. In vivo relationship between pelvis motion and deep fascia displacement of the medial gastrocnemius: anatomical and functional implications

    Science.gov (United States)

    Cruz-Montecinos, Carlos; González Blanche, Alberto; López Sánchez, David; Cerda, Mauricio; Sanzana-Cuche, Rodolfo; Cuesta-Vargas, Antonio

    2015-01-01

    Different authors have modelled myofascial tissue connectivity over a distance using cadaveric models, but in vivo models are scarce. The aim of this study was to evaluate the relationship between pelvic motion and deep fascia displacement in the medial gastrocnemius (MG). Deep fascia displacement of the MG was evaluated through automatic tracking with an ultrasound. Angular variation of the pelvis was determined by 2D kinematic analysis. The average maximum fascia displacement and pelvic motion were 1.501 ± 0.78 mm and 6.55 ± 2.47 °, respectively. The result of a simple linear regression between fascia displacement and pelvic motion for three task executions by 17 individuals was r = 0.791 (P hamstring flexibility was related to a lower anterior tilt of the pelvis (r = 0.544, P < 0.024) and a lower deep fascia displacement of the MG (r = 0.449, P < 0.042). These results support the concept of myofascial tissue connectivity over a distance in an in vivo model, reinforce the functional concept of force transmission through synergistic muscle groups, and grant new perspectives for the role of fasciae in restricting movement in remote zones. PMID:26467242

  3. Effects of sildenafil on the gastrocnemius and cardiac muscles of rats in a model of prolonged moderate exercise training.

    Directory of Open Access Journals (Sweden)

    Barbara Rinaldi

    Full Text Available Moderate exercise training improves energetic metabolism, tissue perfusion and induces cardiac and skeletal muscle remodeling. Sildenafil, a potent phosphodiesterase-5 inhibitor used to treat erectile dysfunction, reduces infarct size and increases tissue oxygenation in experimental models of cardiovascular disease. We have evaluated the effects of prolonged moderate exercise training and a repeat administration of sildenafil on the rat gastrocnemius and cardiac muscles. Animals were divided into two groups: sedentary and trained. Each group was subdivided into animals treated with vehicle or with two doses of sildenafil (10 or 15 mg/kg/day during the last week of training. Physical exercise did not induce cardiac hypertrophy, whereas it increased mRNA levels of the PGC-1α, HIF-1α and VEGF genes, which are involved in mitochondrial biogenesis and angiogenesis, and reduced mRNA levels of FoxO3a, MuRF-1 and Atrogin-1. Sildenafil dose-dependently promoted both angiogenesis, as shown by increased capillary density, and muscle atrophy, as shown by muscle fibre size. These effects were more pronounced in trained animals. Our data confirm the beneficial effects of a moderate and prolonged training on cardiovascular and skeletal systems and document the positive and negative effects of sildenafil on these tissues at doses higher than those used in clinical practice. This report may impact on the use of sildenafil as a substance able to influence sports performance.

  4. Effects of Sildenafil on the Gastrocnemius and Cardiac Muscles of Rats in a Model of Prolonged Moderate Exercise Training

    Science.gov (United States)

    Rinaldi, Barbara; Donniacuo, Maria; Sodano, Loredana; Gritti, Giulia; Signoriello, Simona; Parretta, Elisabetta; Berrino, Liberato; Urbanek, Konrad; Capuano, Annalisa; Rossi, Francesco

    2013-01-01

    Moderate exercise training improves energetic metabolism, tissue perfusion and induces cardiac and skeletal muscle remodeling. Sildenafil, a potent phosphodiesterase-5 inhibitor used to treat erectile dysfunction, reduces infarct size and increases tissue oxygenation in experimental models of cardiovascular disease. We have evaluated the effects of prolonged moderate exercise training and a repeat administration of sildenafil on the rat gastrocnemius and cardiac muscles. Animals were divided into two groups: sedentary and trained. Each group was subdivided into animals treated with vehicle or with two doses of sildenafil (10 or 15 mg/kg/day) during the last week of training. Physical exercise did not induce cardiac hypertrophy, whereas it increased mRNA levels of the PGC-1α, HIF-1α and VEGF genes, which are involved in mitochondrial biogenesis and angiogenesis, and reduced mRNA levels of FoxO3a, MuRF-1 and Atrogin-1. Sildenafil dose-dependently promoted both angiogenesis, as shown by increased capillary density, and muscle atrophy, as shown by muscle fibre size. These effects were more pronounced in trained animals. Our data confirm the beneficial effects of a moderate and prolonged training on cardiovascular and skeletal systems and document the positive and negative effects of sildenafil on these tissues at doses higher than those used in clinical practice. This report may impact on the use of sildenafil as a substance able to influence sports performance. PMID:23922868

  5. Does ankle joint power reflect type of muscle action of soleus and gastrocnemius during walking in cats and humans?

    Science.gov (United States)

    Cronin, Neil J; Prilutsky, Boris I; Lichtwark, Glen A; Maas, Huub

    2013-04-26

    The main objective of this paper is to highlight the difficulties of identifying shortening and lengthening contractions based on analysis of power produced by resultant joint moments. For that purpose, we present net ankle joint powers and muscle fascicle/muscle-tendon unit (MTU) velocities for medial gastrocnemius (MG) and soleus (SO) muscles during walking in species of different size (humans and cats). For the cat, patterns of ankle joint power and MTU velocity of MG and SO during stance were similar: negative power (ankle moment×angular velocityankle joint power and fascicle velocity patterns were observed for MG muscle. In humans, like cats, the patterns of ankle joint power and MTU velocity of SO and MG were similar. Unlike the cat, there were substantial differences between patterns of fascicle velocity and ankle joint power during stance in both muscles. These results indicate that during walking, only a small fraction of mechanical work of the ankle moment is either generated or absorbed by the muscle fascicles, thus confirming the contribution of in-series elastic structures and/or energy transfer via two-joint muscles. We conclude that ankle joint negative power does not necessarily indicate eccentric action of muscle fibers and that positive power cannot be exclusively attributed to muscle concentric action, especially in humans. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Association of Gastrocnemius Muscle Stiffness With Passive Ankle Joint Stiffness and Sex-Related Difference in the Joint Stiffness.

    Science.gov (United States)

    Chino, Kintaro; Takashi, Hideyuki

    2017-11-15

    Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, we assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggest that muscle stiffness of the MG would not be a prominent factor to determine passive ankle joint stiffness and the sex-related difference in the joint stiffness.

  7. Mechanomyogram amplitude correlates with human gastrocnemius medialis muscle and tendon stiffness both before and after acute passive stretching.

    Science.gov (United States)

    Longo, Stefano; Cè, Emiliano; Rampichini, Susanna; Devoto, Michela; Limonta, Eloisa; Esposito, Fabio

    2014-10-01

    The study aimed to assess the level of correlation between muscle-tendon unit (MTU) stiffness and mechanomyogram (MMG) signal amplitude of the human gastrocnemius medialis muscle, both before and after acute passive stretching. The passive torque (Tpass), electrically evoked peak torque (pT) and myotendinous junction displacement were determined at different angles of dorsiflexion (0, 10 and 20 deg), while maximum voluntary isometric torque (Tmax) was assessed only at 0 deg. Measurements were repeated after a bout of passive stretching. From the MMG signal, the root mean square (RMS) and peak to peak (p-p) were calculated. The MTU, muscle and tendon stiffness were determined by ultrasound and Tpass measurements. Before stretching, correlations between MMG RMS and MTU, muscle and tendon stiffness were found (R(2) = 0.22-0.46). After stretching, Tpass, Tmax, pT and MTU, muscle and tendon stiffness decreased by 25 ± 7, 16 ± 2, 9 ± 2, 22 ± 7, 23 ± 8 and 28 ± 5%, respectively (P muscle and tendon stiffness were still present after stretching (R(2) = 0.44-0.60). In conclusion, correlations between MMG RMS and stiffness exist both before and after stretching, suggesting that a slacker MTU leads to larger muscle fibre oscillations. However, care must be taken in using MMG amplitude as an indirect index to estimate stiffness owing to the relatively small R(2) values of the investigated correlations. © 2014 The Authors. Experimental Physiology © 2014 The Physiological Society.

  8. A preliminary study of the effect of restricted gastrocnemius length on foot kinematics and plantar pressure patterns during gait in children with Cerebral Palsy

    DEFF Research Database (Denmark)

    Curtis, Derek

    2008-01-01

      Summary/conclusion Kinematic foot modelling and pedobarography are complementary measurement methods for measuring foot biomechanics in children with cerebral palsy (CP). Pedobarography appears to be the most sensitive instrument measuring significantly decreased hindfoot and increased lateral...... forefoot mean plantar pressure and force in the children with gastrocnemius contracture, whilst the corresponding changes in foot kinematics were non-significant.   Introduction Foot deformity is common in CP and is often due to hypertonia and contracture in spastic muscles. The aim of this study...... was to establish the repeatability of two measurement techniques and establish whether they could be used in the quantification of altered foot kinematics and kinetics that result from gastrocnemius contracture.   Method The gait of 8 healthy children selected at random (5 girls, 3 boys, mean ± SD, 12 ± 3 yrs...

  9. Megane Pro: Myo-electricity, visual and gaze tracking data acquisitions to improve hand prosthetics.

    Science.gov (United States)

    Giordaniello, Francesca; Cognolato, Matteo; Graziani, Mara; Gijsberts, Arjan; Gregori, Valentina; Saetta, Gianluca; Hager, Anne-Gabrielle Mittaz; Tiengo, Cesare; Bassetto, Franco; Brugger, Peter; Caputo, Barbara; Muller, Henning; Atzori, Manfredo

    2017-07-01

    During the past 60 years scientific research proposed many techniques to control robotic hand prostheses with surface electromyography (sEMG). Few of them have been implemented in commercial systems also due to limited robustness that may be improved with multimodal data. This paper presents the first acquisition setup, acquisition protocol and dataset including sEMG, eye tracking and computer vision to study robotic hand control. A data analysis on healthy controls gives a first idea of the capabilities and constraints of the acquisition procedure that will be applied to amputees in a next step. Different data sources are not fused together in the analysis. Nevertheless, the results support the use of the proposed multimodal data acquisition approach for prosthesis control. The sEMG movement classification results confirm that it is possible to classify several grasps with sEMG alone. sEMG can detect the grasp type and also small differences in the grasped object (accuracy: 95%). The simultaneous recording of eye tracking and scene camera data shows that these sensors allow performing object detection for grasp selection and that several neurocognitive parameters need to be taken into account for this. In conclusion, this work on intact subjects presents an innovative acquisition setup and protocol. The first results in terms of data analysis are promising and set the basis for future work on amputees, aiming to improve the robustness of prostheses with multimodal data.

  10. Effect of side dominance on myoelectric manifestations of muscle fatigue in the human upper trapezius muscle

    NARCIS (Netherlands)

    Farina, Dario; Kallenberg, L.A.C.; Merletti, Roberto; Hermens, Hermanus J.

    2003-01-01

    The purpose of this study was to investigate whether differences in the peripheral and control properties of the neuromuscular system due to long-term preferential use, related to side dominance, affect postural muscles, such as the upper trapezius. Therefore, fatigability properties of the upper

  11. Effects of Shoes and a Prefabricated Medial Arch Support on Medial Gastrocnemius and Tibialis Anterior Activity while doing Leg Press Exercise in Normal Feet Athletes

    Directory of Open Access Journals (Sweden)

    Maryam Sheikhi

    2017-04-01

    Full Text Available Background: Nowadays, different types of exercise machines are being used in the field of athletic training, recreation, post-injury and post-operation rehabilitation. Leg press is a commonly-used one that retrains muscles and simulates natural functional activities. In this activity, feet are in contact with a footrest to exert muscular forces. In addition, the footrest inserts reactive forces to feet and from the feet load would transfer to structures that are more proximal. Any misalignment in foot structure may interfere its function. Objective: The aim of this study was to assess the effect of shoes and using a prefabricated medial arch support on the activity of Tibialis anterior and medial gastrocnemius muscles while doing leg press exercise in normal feet subjects. Method: 14 men with normal Medial Longitudinal Arch and normal Body Mass Index aged between 18-35 years old, with at least 6 months experience of doing leg press volunteered to participate in this study.  Medial gastrocnemius and Tibialis anterior activity were measured by surface electromyography while doing leg press with 70% of subjects 1 Repetition Maximum.  To increase accuracy, motion was divided into knee flexion and knee extension phases. Peak Amplitude, Time to Peak Amplitude and Root Mean Square variables were used for analysis. Wilcoxon nonparametric test was used to compare the results. Results: No statistically significant difference was found in the electromyographic parameters of Medial gastrocnemius nor Tibialis anterior in any phases of motion, except for an increase in Tibialis anterior time to peak amplitude in shod condition compared with barefoot in knee extension phase of motion (p-value=0.008 and Tibialis anterior RMS in knee flexion phase in orthotic condition compared to shod (p-value=0.03. Conclusion: It seems that in high loads shoes or medial arch supports cannot change electromyographic parameters in Medial gastrocnemius nor Tibialis anterior in

  12. Virtual Control of Prosthetic Hand Based on Grasping Patterns and Estimated Force from Semg

    Directory of Open Access Journals (Sweden)

    Zhu Gao-Ke

    2016-01-01

    Full Text Available Myoelectric prosthetic hands aim to serve upper limb amputees. The myoelectric control of the hand grasp action is a kind of real-time or online method. Thus it is of great necessity to carry on a study of online prosthetic hand electrical control. In this paper, the strategy of simultaneous EMG decoding of grasping patterns and grasping force was realized by controlling a virtual multi-degree-freedom prosthetic hand and a real one-degree-freedom prosthetic hand simultaneously. The former realized the grasping patterns from the recognition of the sEMG pattern. The other implemented the grasping force from sEMG force decoding. The results show that the control method is effective and feasible.

  13. The effect of subtalar inversion/eversion on the dynamic function of the tibialis anterior, soleus, and gastrocnemius during the stance phase of gait.

    Science.gov (United States)

    Wang, Ruoli; Gutierrez-Farewik, Elena M

    2011-05-01

    The purpose of this study was to determine how gait deviation in one plane (i.e. excessive subtalar inversion/eversion) can affect the dynamic function of the tibialis anterior, gastrocnemius, and soleus to accelerate the subtalar, ankle, knee and hip joints, as well as the body center of mass. Induced acceleration analysis was performed based on a subject-specific three-dimensional linkage model configured by stance phase gait data and driven by one unit of muscle force. Eight healthy adult subjects were examined in gait analysis. The subtalar inversion/eversion was modeled by offsetting up to 20° from the normal subtalar angle while other configurations remained unaltered. This study showed that the gastrocnemius, soleus and tibialis anterior generally functioned as their anatomical definition in normal gait, but counterintuitive function was occasionally found in the bi-articular gastrocnemius. The plantarflexors play important roles in the body support and forward progression. Excessive subtalar eversion was found to enlarge the plantarflexors and tibialis anterior's function. Induced acceleration analysis demonstrated its ability to isolate the contributions of individual muscle to a given factor, and as a means of studying effect of pathological gait on the dynamic muscle functions. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. A ketogenic amino acid rich diet benefits mitochondrial homeostasis by altering the AKT/4EBP1 and autophagy signaling pathways in the gastrocnemius and soleus.

    Science.gov (United States)

    Li, Jinpeng; Kanasaki, Megumi; Xu, Ling; Kitada, Munehiro; Nagao, Kenji; Adachi, Yusuke; Jinzu, Hiroko; Noguchi, Yasushi; Kohno, Miyuki; Kanasaki, Keizo; Koya, Daisuke

    2018-03-14

    Muscle biology is important topic in diabetes research. We have reported that a diet with ketogenic amino acids rich replacement (KAAR) ameliorated high-fat diet (HFD)-induced hepatosteatosis via activation of the autophagy system. Here, we found that a KAAR ameliorated the mitochondrial morphological alterations and associated mitochondrial dysfunction induced by an HFD through induction of the AKT/4EBP1 and autophagy signaling pathways in both fast and slow muscles. The mice were fed with a standard HFD (30% fat in food) or an HFD with KAAR (HFD KAAR ). In both the gastrocnemius and the soleus, HFD KAAR ameliorated HFD-impaired mitochondrial morphology and mitochondrial function, characterized by decreased mitofusin 2, optic atrophy 1, peroxisome proliferator-activated receptor (PPAR) γ coactivator-1α and PPARα levels and increased dynamin-related protein 1 levels. The decreased levels of phosphorylated AKT and 4EBP1 in the gastrocnemius and soleus of HFD-fed mice were remediated by HFD KAAR . Furthermore, the HFD KAAR ameliorated the HFD-induced autophagy defects in the gastrocnemius and soleus. These findings suggest that KAAR may be a novel strategy to combat obesity-induced mitochondrial dysfunction, likely through induction of the AKT/4EBP1 and autophagy pathways in skeletal muscle. Copyright © 2018. Published by Elsevier B.V.

  15. Especificidade da atividade mioelétrica no agachamento excêntrico declinado em 25º e no agachamento padrão com diferentes sobrecargas Specificity of the myoelectrical activity on the eccentric decline squat at 25º and standard squat with different overloads

    Directory of Open Access Journals (Sweden)

    Gustavo Leporace

    2010-06-01

    sugerem que esse exercício deve ser utilizado com cautela, já que o sinergismo muscular entre os músculos testados mostrou-se alterado em decorrência de modificações no status direcional da superfície de apoio, o que pode comprometer a especificidade da exercitação em relação a atividades específicas, como as esportivas, nomeadamente quanto ao aspecto coordenação.OBJECTIVE: The aim of this study was to compare the myoelectrical activity between the single-leg decline squat and the single-leg standard squat, with two different overloads. PARTICIPANTS: A group of eight recreationally trained subjects with no signs or symptoms of injury in the lower limb. PROCEDURES: On different days, the subjects performed two distinct kinds of unilateral eccentric squat, differentiated by the direction of the base of support, being one flat and the other declined at 25°. These two squats were carried out with two different overloads: with no extra overload and with an overload that represented 15 maximum repetitions (RM. OUTCOME MEASURES: The myoelectrical activities of the rectus femoris, vastus lateralis, medial hamstrings and gastrocnemius medialis were measured in the four test conditions (Flat and Decline Squat with and without extra overload. RESULTS: The quadriceps muscles were sensitive to the platform angle, showing greater activity on the decline squat; however, they did not show increase in the activation when overload was added. The medial hamstrings and gastrocnemius medialis were not sensitive to the platform angle or to the overload increase. In spite of the alterations in the muscular co-contraction ratio in several situations, we did not find any statistically significant differences among the four conditions tested. CONCLUSION: The results confirmed the higher activation of quadriceps generated in the decline squat compared to the standard squat, suggesting that this exercise is an interesting choice for rehabilitation management of patellar tendinopathy

  16. Can We Achieve Intuitive Prosthetic Elbow Control Based on Healthy Upper Limb Motor Strategies?

    Science.gov (United States)

    Merad, Manelle; de Montalivet, Étienne; Touillet, Amélie; Martinet, Noël; Roby-Brami, Agnès; Jarrassé, Nathanaël

    2018-01-01

    Most transhumeral amputees report that their prosthetic device lacks functionality, citing the control strategy as a major limitation. Indeed, they are required to control several degrees of freedom with muscle groups primarily used for elbow actuation. As a result, most of them choose to have a one-degree-of-freedom myoelectric hand for grasping objects, a myoelectric wrist for pronation/supination, and a body-powered elbow. Unlike healthy upper limb movements, the prosthetic elbow joint angle, adjusted prior to the motion, is not involved in the overall upper limb movements, causing the rest of the body to compensate for the lack of mobility of the prosthesis. A promising solution to improve upper limb prosthesis control exploits the residual limb mobility: like in healthy movements, shoulder and prosthetic elbow motions are coupled using inter-joint coordination models. The present study aims to test this approach. A transhumeral amputated individual used a prosthesis with a residual limb motion-driven elbow to point at targets. The prosthetic elbow motion was derived from IMU-based shoulder measurements and a generic model of inter-joint coordinations built from healthy individuals data. For comparison, the participant also performed the task while the prosthetic elbow was implemented with his own myoelectric control strategy. The results show that although the transhumeral amputated participant achieved the pointing task with a better precision when the elbow was myoelectrically-controlled, he had to develop large compensatory trunk movements. Automatic elbow control reduced trunk displacements, and enabled a more natural body behavior with synchronous shoulder and elbow motions. However, due to socket impairments, the residual limb amplitudes were not as large as those of healthy shoulder movements. Therefore, this work also investigates if a control strategy whereby prosthetic joints are automatized according to healthy individuals' coordination models can

  17. Can We Achieve Intuitive Prosthetic Elbow Control Based on Healthy Upper Limb Motor Strategies?

    Directory of Open Access Journals (Sweden)

    Manelle Merad

    2018-02-01

    Full Text Available Most transhumeral amputees report that their prosthetic device lacks functionality, citing the control strategy as a major limitation. Indeed, they are required to control several degrees of freedom with muscle groups primarily used for elbow actuation. As a result, most of them choose to have a one-degree-of-freedom myoelectric hand for grasping objects, a myoelectric wrist for pronation/supination, and a body-powered elbow. Unlike healthy upper limb movements, the prosthetic elbow joint angle, adjusted prior to the motion, is not involved in the overall upper limb movements, causing the rest of the body to compensate for the lack of mobility of the prosthesis. A promising solution to improve upper limb prosthesis control exploits the residual limb mobility: like in healthy movements, shoulder and prosthetic elbow motions are coupled using inter-joint coordination models. The present study aims to test this approach. A transhumeral amputated individual used a prosthesis with a residual limb motion-driven elbow to point at targets. The prosthetic elbow motion was derived from IMU-based shoulder measurements and a generic model of inter-joint coordinations built from healthy individuals data. For comparison, the participant also performed the task while the prosthetic elbow was implemented with his own myoelectric control strategy. The results show that although the transhumeral amputated participant achieved the pointing task with a better precision when the elbow was myoelectrically-controlled, he had to develop large compensatory trunk movements. Automatic elbow control reduced trunk displacements, and enabled a more natural body behavior with synchronous shoulder and elbow motions. However, due to socket impairments, the residual limb amplitudes were not as large as those of healthy shoulder movements. Therefore, this work also investigates if a control strategy whereby prosthetic joints are automatized according to healthy individuals

  18. Cross Time-Frequency Analysis of Gastrocnemius Electromyographic Signals in Hypertensive and Nonhypertensive Subjects

    Science.gov (United States)

    Mitchell, Patrick; Krotish, Debra; Shin, Yong-June; Hirth, Victor

    2010-12-01

    The effects of hypertension are chronic and continuous; it affects gait, balance, and fall risk. Therefore, it is desirable to assess gait health across hypertensive and nonhypertensive subjects in order to prevent or reduce the risk of falls. Analysis of electromyography (EMG) signals can identify age related changes of neuromuscular activation due to various neuropathies and myopathies, but it is difficult to translate these medical changes to clinical diagnosis. To examine and compare geriatrics patients with these gait-altering diseases, we acquire EMG muscle activation signals, and by use of a timesynchronized mat capable of recording pressure information, we localize the EMG data to the gait cycle, ensuring identical comparison across subjects. Using time-frequency analysis on the EMG signal, in conjunction with several parameters obtained from the time-frequency analyses, we can determine the statistical discrepancy between diseases. We base these parameters on physiological manifestations caused by hypertension, as well as other comorbities that affect the geriatrics community. Using these metrics in a small population, we identify a statistical discrepancy between a control group and subjects with hypertension, neuropathy, diabetes, osteoporosis, arthritis, and several other common diseases which severely affect the geriatrics community.

  19. Wavelet transform and real-time learning method for myoelectric signal in motion discrimination

    International Nuclear Information System (INIS)

    Liu Haihua; Chen Xinhao; Chen Yaguang

    2005-01-01

    This paper discusses the applicability of the Wavelet transform for analyzing an EMG signal and discriminating motion classes. In many previous works, researchers have dealt with steady EMG and have proposed suitable analyzing methods for the EMG, for example FFT and STFT. Therefore, it is difficult for the previous approaches to discriminate motions from the EMG in the different phases of muscle activity, i.e., pre-activity, in activity, postactivity phases, as well as the period of motion transition from one to another. In this paper, we introduce the Wavelet transform using the Coiflet mother wavelet into our real-time EMG prosthetic hand controller for discriminating motions from steady and unsteady EMG. A preliminary experiment to discriminate three hand motions from four channel EMG in the initial pre-activity and in activity phase is carried out to show the effectiveness of the approach. However, future research efforts are necessary to discriminate more motions much precisely

  20. GLIMPSE: Google Glass interface for sensory feedback in myoelectric hand prostheses

    Science.gov (United States)

    Markovic, Marko; Karnal, Hemanth; Graimann, Bernhard; Farina, Dario; Dosen, Strahinja

    2017-06-01

    Objective. Providing sensory feedback to the user of the prosthesis is an important challenge. The common approach is to use tactile stimulation, which is easy to implement but requires training and has limited information bandwidth. In this study, we propose an alternative approach based on augmented reality. Approach. We have developed the GLIMPSE, a Google Glass application which connects to the prosthesis via a Bluetooth interface and renders the prosthesis states (EMG signals, aperture, force and contact) using augmented reality (see-through display) and sound (bone conduction transducer). The interface was tested in healthy subjects that used the prosthesis with (FB group) and without (NFB group) feedback during a modified clothespins test that allowed us to vary the difficulty of the task. The outcome measures were the number of unsuccessful trials, the time to accomplish the task, and the subjective ratings of the relevance of the feedback. Main results. There was no difference in performance between FB and NFB groups in the case of a simple task (basic, same-color clothespins test), but the feedback significantly improved the performance in a more complex task (pins of different resistances). Importantly, the GLIMPSE feedback did not increase the time to accomplish the task. Therefore, the supplemental feedback might be useful in the tasks which are more demanding, and thereby less likely to benefit from learning and feedforward control. The subjects integrated the supplemental feedback with the intrinsic sources (vision and muscle proprioception), developing their own idiosyncratic strategies to accomplish the task. Significance. The present study demonstrates a novel self-contained, ready-to-deploy, wearable feedback interface. The interface was successfully tested and was proven to be feasible and functionally beneficial. The GLIMPSE can be used as a practical solution but also as a general and flexible instrument to investigate closed-loop prosthesis

  1. How much does the human medial gastrocnemius muscle contribute to ankle torques outside the sagittal plane?☆

    Science.gov (United States)

    Vieira, Taian M.M.; Minetto, Marco A.; Hodson-Tole, Emma F.; Botter, Alberto

    2013-01-01

    Ankle movements in the frontal plane are less prominent though not less relevant than movements in the plantar or dorsal flexion direction. Walking on uneven terrains and standing on narrow stances are examples of circumstances likely imposing marked demands on the ankle medio-lateral stabilization. Following our previous evidence associating lateral bodily sways in quiet standing to activation of the medial gastrocnemius (MG) muscle, in this study we ask: how large is the MG contribution to ankle torque in the frontal plane? By arranging stimulation electrodes in a selective configuration, current pulses were applied primarily to the MG nerve branch of ten subjects. The contribution of populations of MG motor units of progressively smaller recruitment threshold to ankle torque was evaluated by increasing the stimulation amplitude by fixed amounts. From smallest intensities (12–32 mA) leading to the firstly observable MG twitches in force-plate recordings, current pulses reached intensities (56–90 mA) below which twitches in other muscles could not be observed from the skin. Key results showed a substantial MG torque contribution tending to rotate upward the foot medial aspect (ankle inversion). Nerve stimulation further revealed a linear relationship between the peak torque of ankle plantar flexion and inversion, across participants (Pearson R > .81, p torque of ankle inversion amounted to about 13% of plantar flexion peak torque. Physiologically, these results provide experimental evidence that MG activation may contribute to stabilize the body in the frontal plane, especially under situations of challenged stability. PMID:23992638

  2. Sensor fusion and computer vision for context-aware control of a multi degree-of-freedom prosthesis

    Science.gov (United States)

    Markovic, Marko; Dosen, Strahinja; Popovic, Dejan; Graimann, Bernhard; Farina, Dario

    2015-12-01

    Objective. Myoelectric activity volitionally generated by the user is often used for controlling hand prostheses in order to replicate the synergistic actions of muscles in healthy humans during grasping. Muscle synergies in healthy humans are based on the integration of visual perception, heuristics and proprioception. Here, we demonstrate how sensor fusion that combines artificial vision and proprioceptive information with the high-level processing characteristics of biological systems can be effectively used in transradial prosthesis control. Approach. We developed a novel context- and user-aware prosthesis (CASP) controller integrating computer vision and inertial sensing with myoelectric activity in order to achieve semi-autonomous and reactive control of a prosthetic hand. The presented method semi-automatically provides simultaneous and proportional control of multiple degrees-of-freedom (DOFs), thus decreasing overall physical effort while retaining full user control. The system was compared against the major commercial state-of-the art myoelectric control system in ten able-bodied and one amputee subject. All subjects used transradial prosthesis with an active wrist to grasp objects typically associated with activities of daily living. Main results. The CASP significantly outperformed the myoelectric interface when controlling all of the prosthesis DOF. However, when tested with less complex prosthetic system (smaller number of DOF), the CASP was slower but resulted with reaching motions that contained less compensatory movements. Another important finding is that the CASP system required minimal user adaptation and training. Significance. The CASP constitutes a substantial improvement for the control of multi-DOF prostheses. The application of the CASP will have a significant impact when translated to real-life scenarious, particularly with respect to improving the usability and acceptance of highly complex systems (e.g., full prosthetic arms) by amputees.

  3. Sensor fusion and computer vision for context-aware control of a multi degree-of-freedom prosthesis.

    Science.gov (United States)

    Markovic, Marko; Dosen, Strahinja; Popovic, Dejan; Graimann, Bernhard; Farina, Dario

    2015-12-01

    Myoelectric activity volitionally generated by the user is often used for controlling hand prostheses in order to replicate the synergistic actions of muscles in healthy humans during grasping. Muscle synergies in healthy humans are based on the integration of visual perception, heuristics and proprioception. Here, we demonstrate how sensor fusion that combines artificial vision and proprioceptive information with the high-level processing characteristics of biological systems can be effectively used in transradial prosthesis control. We developed a novel context- and user-aware prosthesis (CASP) controller integrating computer vision and inertial sensing with myoelectric activity in order to achieve semi-autonomous and reactive control of a prosthetic hand. The presented method semi-automatically provides simultaneous and proportional control of multiple degrees-of-freedom (DOFs), thus decreasing overall physical effort while retaining full user control. The system was compared against the major commercial state-of-the art myoelectric control system in ten able-bodied and one amputee subject. All subjects used transradial prosthesis with an active wrist to grasp objects typically associated with activities of daily living. The CASP significantly outperformed the myoelectric interface when controlling all of the prosthesis DOF. However, when tested with less complex prosthetic system (smaller number of DOF), the CASP was slower but resulted with reaching motions that contained less compensatory movements. Another important finding is that the CASP system required minimal user adaptation and training. The CASP constitutes a substantial improvement for the control of multi-DOF prostheses. The application of the CASP will have a significant impact when translated to real-life scenarious, particularly with respect to improving the usability and acceptance of highly complex systems (e.g., full prosthetic arms) by amputees.

  4. High-density EMG E-textile systems for the control of active prostheses.

    Science.gov (United States)

    Farina, Dario; Lorrain, Thomas; Negro, Francesco; Jiang, Ning

    2010-01-01

    Myoelectric control of active prostheses requires electrode systems that are easy to apply for daily repositioning of the electrodes by the user. In this study we propose the use of Smart Fabric and Interactive Textile (SFIT) systems as an alternative solution for recording high-density EMG signals for myoelectric control. A sleeve covering the upper and lower arm, which contains 100 electrodes arranged in four grids of 5 × 5 electrodes, was used to record EMG signals in 3 subjects during the execution of 9 tasks of the wrist and hand. The signals were analyzed by extracting wavelet coefficients which were classified with linear discriminant analysis. The average classification accuracy for the nine tasks was 89.1 ± 1.9 %. These results show that SFIT systems can be used as an effective way for muscle-machine interfacing.

  5. Relationship of medial gastrocnemius relative fascicle excursion and ankle joint power and work performance during gait in typically developing children: A cross-sectional study.

    Science.gov (United States)

    Martín Lorenzo, Teresa; Albi Rodríguez, Gustavo; Rocon, Eduardo; Martínez Caballero, Ignacio; Lerma Lara, Sergio

    2017-07-01

    Muscle fascicles lengthen in response to chronic passive stretch through in-series sarcomere addition in order to maintain an optimum sarcomere length. In turn, the muscles' force generating capacity, maximum excursion, and contraction velocity is enhanced. Thus, longer fascicles suggest a greater capacity to develop joint power and work. However, static fascicle length measurements may not be taking sarcomere length differences into account. Thus, we considered relative fascicle excursions through passive ankle dorsiflexion may better correlate with the capacity to generate joint power and work than fascicle length. Therefore, the aim of the present study was to determine if medial gastrocnemius relative fascicle excursions correlate with ankle joint power and work generation during gait in typically developing children. A sample of typically developing children (n = 10) were recruited for this study and data analysis was carried out on 20 legs. Medial gastrocnemius relative fascicle excursion from resting joint angle to maximum dorsiflexion was estimated from trigonometric relations of medial gastrocnemius pennation angle and thickness obtained from B-mode real-time ultrasonography. Furthermore, a three-dimensional motion capture system was used to obtain ankle joint work and power during the stance phase of gait. Significant correlations were found between relative fascicle excursion and peak power absorption (-) r(14) = -0.61, P = .012 accounting for 31% variability, positive work r(18) = 0.56, P = .021 accounting for 31% variability, and late stance positive work r(15) = 0.51, P = .037 accounting for 26% variability. The large unexplained variance may be attributed to mechanics of neighboring structures (e.g., soleus or Achilles tendon mechanics) and proximal joint kinetics which may also contribute to ankle joint power and work performance, and were not taken into account. Further studies are encouraged to provide greater insight

  6. Task-dependent inhibition of slow-twitch soleus and excitation of fast-twitch gastrocnemius do not require high movement speed and velocity-dependent sensory feedback

    Directory of Open Access Journals (Sweden)

    Ricky eMehta

    2014-10-01

    Full Text Available Although individual heads of triceps surae, soleus (SO and medial gastrocnemius (MG muscles, are often considered close functional synergists, previous studies have shown distinct activity patterns between them in some motor behaviors. The goal of this study was to test two hypotheses explaining inhibition of slow SO with respect to fast MG: (1 inhibition occurs at high movement velocities and mediated by velocity-dependent sensory feedback and (2 inhibition depends on the ankle-knee joint moment combination and does not require high movement velocities. The hypotheses were tested by comparing the SO EMG/MG EMG ratio during fast and slow motor behaviors (cat paw shake responses vs. back, straight leg load lifting in humans, which had the same ankle extension-knee flexion moment combination; and during fast and slow behaviors with the ankle extension-knee extension moment combination (human vertical jumping and stance phase of walking in cats and leg load lifting in humans. In addition, SO EMG/MG EMG ratio was determined during cat paw shake responses and walking before and after removal of stretch velocity-dependent sensory feedback by self-reinnervating SO and/or gastrocnemius. We found the ratio SO EMG/MG EMG below 1 (p<0.05 during fast paw shake responses and slow back load lifting, requiring the ankle extension-knee flexion moment combination; whereas the ratio SO EMG/MG EMG was above 1 (p<0.05 during fast vertical jumping and slow tasks of walking and leg load lifting, requiring ankle extension-knee extension moments. Removal of velocity-dependent sensory feedback did not affect the SO EMG/MG EMG ratio in cats. We concluded that the relative inhibition of SO does not require high muscle velocities, depends on ankle-knee moment combinations, and is mechanically advantageous for allowing a greater MG contribution to ankle extension and knee flexion moments.

  7. Evaluation of Reliability of H-Reflex Recruitment Curve Parameters of Soleus and Lateral Gastrocnemius Muscles in Assessment of Motor Neuron Pools Excitability

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    Rasool Bagheri

    2013-09-01

    Full Text Available Background and Objectives: In Recent years, recording of the H-reflex recruitment curve for assessment of the excitability of group Ia afferent monosynaptic reflex has been growing. The purpose of this study was to evaluate the reliability of H-reflex recruitment curve parameters of gasterosoleus muscle in the assessment of motor neuron pool excitability.Methods: In this descriptive study, 50 non-athlete healthy volunteers were assessed. Percutaneously, 40 electrical pulses of 1 millisecond duration and 3 stimulations per each stimulus intensity were induced on tibial nerves and H-reflex recruitment curve were recorded in 4 phases. Also, each person was assessed in two sessions with 1-week interval.Results: The intraclass correlation coefficients ICCs( was obtained between 0.97-0.99 for inter-session reliability of intensity for recording the threshold, HMax and HLast reflexes, amplitude of HMax, and the total slope of the ascending and descending arms. The inter-session correlation coefficient (test-retest of these variables were obtained between 0.91-0.95 for soleus muscle, and the inter-session ICCs for peak-to-peak amplitude of HMax and the total slope of the ascending arm of gastrocnemius were obtained 0.65 and 0.67. The slope of initial and final three points of the ascending arm revealed a different reliability in inter-session and intra-session reliability analysis (0.64-0.96. Conclusion: The reliability analysis showed a high inter-session and intra-session ICCs for the functional principal components of soleus recruitment curve. Also, recruitment curve parameters, such as intensity for record of threshold and HMax of soleus and lateral gastrocnemius muscles as well as total slope of ascending and descending arms, and peak to peak amplitude of HMax of soleus muscle had a very high Reliability.

  8. Propriedades mecânicas do músculo gastrocnêmio de ratas, imobilizado e posteriormente submetido a diferentes protocolos de alongamento Mechanical properties of gastrocnemius muscle of female rats immobilized and posteriorly submitted to different stretching protocols

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    Juliana Cristina Polizello

    2009-06-01

    Full Text Available O alongamento é amplamente utilizado na prática clínica da fisioterapia e no desporto, porém, as alterações mecânicas que essa técnica gera no músculo esquelético são pouco exploradas cientificamente. Este estudo avaliou as alterações mecânicas que acometem o músculo gastrocnêmio de ratas Wistar, adultas jovens, após 14 dias de imobilização e, secundariamente, submetido a alongamento manual passivo por 10 dias consecutivos, aplicado uma ou duas vezes ao dia. Foram utilizados 50 animais, sendo 10 para cada grupo: Controle (GC; Imobilizado (GI; Imobilizado e Liberado (GIL; Imobilizado e alongado uma vez ao dia (GIA1; e Imobilizado e alongado duas vezes ao dia (GIA2. O músculo gastrocnêmio foi submetido ao ensaio mecânico de tração, onde foram avaliadas as propriedades de carga e alongamento nos limites máximo e proporcional, além de rigidez e resiliência. A imobilização reduziu os valores das propriedades mecânicas de carga no limite máximo (CLM, carga no limite proporcional (CLP, alongamento no limite máximo (ALM, rigidez e resiliência, em 44,4%, 34,4%, 27,6%, 64,4% e 54%, respectivamente, quando comparados com os valores do GC. A remobilização livre e o alongamento restauraram as propriedades de CLM, CLP, ALM, rigidez e resiliência do músculo, exceto para o GIA2, que foi incapaz de restabelecer a propriedade de ALM (31,3% menor que GC. Concluí-se, portanto que, após 14 dias de imobilização segmentar, cargas individuais de alongamento e a livre movimentação permitem restituir as propriedades mecânicas do tecido muscular.Stretching is widely employed in physiotherapeutic clinical practice and in sportive activities; however, the mechanical alterations of the skeletal muscle generated by this technique are poorly scientifically investigated. This study evaluated the mechanical alterations suffered by the gastrocnemius muscle of young adult female Wistar rats, submitted to14 days of immobilization followed

  9. Central motor control failure in fibromyalgia: a surface electromyography study

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    Buskila Dan

    2009-07-01

    Full Text Available Abstract Background Fibromyalgia (FM is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Methods Eight female patients aged 55.6 ± 13.6 years (FM group and eight healthy female volunteers aged 50.3 ± 9.3 years (MCG were studied by means of non-invasive surface electromyography (s-EMG involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited contractions. Maximal voluntary contractions (MVCs, motor unit action potential conduction velocity distributions (mean ± SD and skewness, and the mean power frequency of the spectrum (MNF were estimated in order to assess whether there were any significant differences between the two groups and contraction types. Results The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 ± 0.052%/s in FM vs -0.196 ± 0.133%/s in MCG; normalised MNF rate of changes: -0.29 ± 0.16%/s in FM vs -0.66 ± 0.34%/s in MCG. Mean conduction velocity distribution and skewnesses values were higher (p Conclusion The apparent paradox of fewer myoelectrical manifestations of fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered

  10. Time course of functional recovery during the first 3 mo after surgical transection and repair of nerves to the feline soleus and lateral gastrocnemius muscles.

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    Gregor, Robert J; Maas, Huub; Bulgakova, Margarita A; Oliver, Alanna; English, Arthur W; Prilutsky, Boris I

    2018-03-01

    Locomotion outcomes after peripheral nerve injury and repair in cats have been described in the literature for the period immediately following the injury (muscle denervation period) and then again for an ensuing period of long-term recovery (at 3 mo and longer) resulting in muscle self-reinnervation. Little is known about the changes in muscle activity and walking mechanics during midrecovery, i.e., the early reinnervation period that takes place between 5 and 10 wk of recovery. Here, we investigated hindlimb mechanics and electromyogram (EMG) activity of ankle extensors in six cats during level and slope walking before and every 2 wk thereafter in a 14-wk period of recovery after the soleus (SO) and lateral gastrocnemius (LG) muscle nerves in one hindlimb were surgically transected and repaired. We found that the continued increase in SO and LG EMG magnitudes and corresponding changes in hindlimb mechanics coincided with the formation of neuromuscular synapses revealed in muscle biopsies. Throughout the recovery period, EMG magnitude of SO and LG during the stance phase and the duration of the stance-related activity were load dependent, similar to those in the intact synergistic medial gastrocnemius and plantaris. These results and the fact that EMG activity of ankle extensors and locomotor mechanics during level and upslope walking recovered 14 wk after nerve transection and repair suggest that loss of the stretch reflex in self-reinnervated muscles may be compensated by the recovered force-dependent feedback in self-reinnervated muscles, by increased central drive, and by increased gain in intermuscular motion-dependent pathways from intact ankle extensors. NEW & NOTEWORTHY This study provides new evidence that the timeline for functional recovery of gait after peripheral nerve injury and repair is consistent with the time required for neuromuscular junctions to form and muscles to reach preoperative tensions. Our findings suggest that a permanent loss of

  11. Medial gastrocnemius muscle stiffness cannot explain the increased ankle joint range of motion following passive stretching in children with cerebral palsy.

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    Kalkman, Barbara M; Bar-On, Lynn; Cenni, Francesco; Maganaris, Constantinos N; Bass, Alfie; Holmes, Gill; Desloovere, Kaat; Barton, Gabor J; O'Brien, Thomas D

    2018-03-01

    What is the central question of this study? Can the increased range of motion seen acutely after stretching in children with cerebral palsy be explained by changes in the stiffness of the medial gastrocnemius fascicles? What is the main finding and its importance? We show, for the first time, that passive muscle and tendon properties are not changed acutely after a single bout of stretching in children with cerebral palsy and, therefore, do not contribute to the increase in range of motion. This contradicts common belief and what happens in healthy adults. Stretching is often used to increase or maintain the joint range of motion (ROM) in children with cerebral palsy (CP), but the effectiveness of these interventions is limited. Therefore, our aim was to determine the acute changes in muscle-tendon lengthening properties that contribute to increased ROM after a bout of stretching in children with CP. Eleven children with spastic CP [age 12.1 (3 SD) years, 5/6 hemiplegia/diplegia, 7/4 gross motor function classification system level I/II] participated. Each child received three sets of five × 20 s passive, manual static dorsiflexion stretches separated by 30 s rest, with 60 s rest between sets. Before and immediately after stretching, ultrasound was used to measure medial gastrocnemius fascicle lengthening continuously over the full ROM and an individual common ROM pre- to post-stretching. Simultaneously, three-dimensional motion of two marker clusters on the shank and the foot was captured to calculate ankle angle, and ankle joint torque was calculated from manually applied torques and forces on a six degrees-of-freedom load cell. After stretching, the ROM was increased [by 9.9 (12.0) deg, P = 0.005]. Over a ROM common to both pre- and post-measurements, there were no changes in fascicle lengthening or torque. The maximal ankle joint torque tolerated by the participants increased [by 2.9 (2.4) N m, P = 0.003], and at this highest passive torque the

  12. The Acute Effects of Unilateral Ankle Plantar Flexors Static- Stretching on Postural Sway and Gastrocnemius Muscle Activity During Single-Leg Balance Tasks

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    Bráulio N. Lima, Paulo R.G. Lucareli, Willy A. Gomes, Josinaldo J. Silva, Andre S. Bley, Erin H. Hartigan, Paulo H. Marchetti

    2014-09-01

    Full Text Available The aim of this study was to investigate the acute effects of unilateral ankle plantar flexors static- stretching on surface electromyography (sEMG and the center of pressure (COP during a single-leg balance task in both lower limbs. Fourteen young healthy, non-athletic individuals performed unipodal quiet standing for 30s before and after (stretched limb: immediately post-stretch, 10 and 20 minutes and non-stretched limb: immediately post-stretch a unilateral ankle plantar flexor static- stretching protocol [6 sets of 45s/15s, 70-90% point of discomfort (POD]. Postural sway was described using the COP area, COP speed (antero-posterior and medio-lateral directions and COP frequency (antero-posterior and medio-lateral directions. Surface EMG (EMG integral [IEMG] and Median frequency[FM] was used to describe the muscular activity of gastrocnemius lateralis. Ankle dorsiflexion passive range of motion increased in the stretched limb before and after the static-stretching protocol (mean ± SD: 15.0° ± 6.0 and 21.5° ± 7.0 [p < 0.001]. COP area and IEMG increased in the stretch limb between pre-stretching and immediately post-stretching (p = 0.015 and p = 0.036, respectively. In conclusion, our static- stretching protocol effectively increased passive ankle ROM. The increased ROM appears to increase postural sway and muscle activity; however these finding were only a temporary or transient effect.

  13. Effect of frozen storage duration and cooking on physical and oxidative changes in M. Gastrocnemius pars interna and M. Iliofiburalis of Rhea americana.

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    Filgueras, R S; Gatellier, P; Zambiazi, R C; Santé-Lhoutellier, V

    2011-08-01

    This study was conducted to evaluate the effect of frozen storage time (30, 60, 90 or 180 days) and cooking (100 °C, 30 min) on the physical characteristics and oxidative stability of M. Gastrocnemius pars interna (GN) and M. Iliofiburalis (IF) of rhea americana. Physical parameters measured included thawing and cooking loss, colour parameters (L*a*b*), while oxidation was assessed by determining the TBA-RS, carbonyl and aromatic amino acid content. Prolonged frozen storage of rhea meat decreased lightness (L*), yellowness (b*), and increased the discoloration parameter hue angle and redness a*. During storage, muscle IF was more prone to lipid and myoglobin oxidation than muscle GN. Cooking loss declined with the increase of storage time and was higher in GN than in IF muscle. With cooking, TBA-RS, carbonyl content, and aromatic amino acids (phenylalanine, tyrosine, and tryptophan) were highly affected, but the extent of oxidation ranged according to muscle and duration of frozen storage. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Structural adaptations of rat lateral gastrocnemius muscle-tendon complex to a chronic stretching program and their quantification based on ultrasound biomicroscopy and optical microscopic images.

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    Peixinho, Carolina Carneiro; Martins, Natália Santos Fonseca; de Oliveira, Liliam Fernandes; Machado, João Carlos

    2014-01-01

    A chronic regimen of flexibility training can increase range of motion, with the increase mechanisms believed to be a change in the muscle material properties or in the neural components associated with this type of training. This study followed chronic structural adaptations of lateral gastrocnemius muscle of rats submitted to stretching training (3 times a week during 8weeks), based on muscle architecture measurements including pennation angle, muscle thickness and tendon length obtained from ultrasound biomicroscopic images, in vivo. Fiber length and sarcomere number per 100μm were determined in 3 fibers of each muscle (ex vivo and in vitro, respectively), using conventional optical microscopy. Stretching training resulted in a significant pennation angle reduction of the stretched leg after 12 sessions (25%, P=0.002 to 0.024). Muscle thickness and tendon length presented no significant changes. Fiber length presented a significant increase for the stretched leg (8.5%, P=0.00006), with the simultaneous increase in sarcomere length (5%, P=0.041) since the stretched muscles presented less sarcomeres per 100μm. A stretching protocol with characteristics similar to those applied in humans was sufficient to modify muscle architecture of rats with absence of a sarcomerogenesis process. The results indicate that structural adaptations take place in skeletal muscle tissue submitted to moderate-intensity stretching training. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Changes in Passive Properties of the Gastrocnemius Muscle-Tendon Unit During a 4-Week Routine Static-Stretching Program.

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    Nakamura, Masatoshi; Ikezoe, Tome; Umegaki, Hiroki; Kobayashi, Takuya; Nishishita, Satoru; Ichihashi, Noriaki

    2017-07-01

    Static stretching (SS) is commonly performed in a warm-up routine to increase joint range of motion (ROM) and to decrease muscle stiffness. However, the time course of changes in ankle-dorsiflexion (DF) ROM and muscle stiffness during a routine SS program is unclear. To investigate changes in ankle-DF ROM, passive torque at DF ROM, and muscle stiffness during a routine SS program performed 3 times weekly for 4 wk. A quasi-randomized controlled-trial design. The subjects comprised 24 male volunteers (age 23.8 ± 2.3 y, height 172.0 ± 4.3 cm, body mass 63.1 ± 4.5 kg) randomly assigned to either a group performing a 4-wk stretching program (SS group) or a control group. DF ROM, passive torque, and muscle stiffness were measured during passive ankle dorsiflexion in both groups using a dynamometer and ultrasonography once weekly during the 4-wk intervention period. In the SS group, DF ROM and passive torque at DF ROM significantly increased after 2, 3, and 4 wk compared with the initial measurements. Muscle stiffness also decreased significantly after 3 and 4 wk in the SS group. However, there were no significant changes in the control group. Based on these results, the SS program effectively increased DF ROM and decreased muscle stiffness. Furthermore, an SS program of more than 2 wk duration effectively increased DF ROM and changed the stretch tolerance, and an SS program more than 3 wk in duration effectively decreased muscle stiffness.

  16. Surveying the interest of individuals with upper limb loss in novel prosthetic control techniques.

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    Engdahl, Susannah M; Christie, Breanne P; Kelly, Brian; Davis, Alicia; Chestek, Cynthia A; Gates, Deanna H

    2015-06-13

    Novel techniques for the control of upper limb prostheses may allow users to operate more complex prostheses than those that are currently available. Because many of these techniques are surgically invasive, it is important to understand whether individuals with upper limb loss would accept the associated risks in order to use a prosthesis. An online survey of individuals with upper limb loss was conducted. Participants read descriptions of four prosthetic control techniques. One technique was noninvasive (myoelectric) and three were invasive (targeted muscle reinnervation, peripheral nerve interfaces, cortical interfaces). Participants rated how likely they were to try each technique if it offered each of six different functional features. They also rated their general interest in each of the six features. A two-way repeated measures analysis of variance with Greenhouse-Geisser corrections was used to examine the effect of the technique type and feature on participants' interest in each technique. Responses from 104 individuals were analyzed. Many participants were interested in trying the techniques - 83 % responded positively toward myoelectric control, 63 % toward targeted muscle reinnervation, 68 % toward peripheral nerve interfaces, and 39 % toward cortical interfaces. Common concerns about myoelectric control were weight, cost, durability, and difficulty of use, while the most common concern about the invasive techniques was surgical risk. Participants expressed greatest interest in basic prosthesis features (e.g., opening and closing the hand slowly), as opposed to advanced features like fine motor control and touch sensation. The results of these investigations may be used to inform the development of future prosthetic technologies that are appealing to individuals with upper limb loss.

  17. Effect of vibrotactile feedback on an EMG-based proportional cursor control system.

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    Li, Shunchong; Chen, Xingyu; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

    2013-01-01

    Surface electromyography (sEMG) has been introduced into the bio-mechatronics systems, however, most of them are lack of the sensory feedback. In this paper, the effect of vibrotactile feedback for a myoelectric cursor control system is investigated quantitatively. Simultaneous and proportional control signals are extracted from EMG using a muscle synergy model. Different types of feedback including vibrotactile feedback and visual feedback are added, assessed and compared with each other. The results show that vibrotactile feedback is capable of improving the performance of EMG-based human machine interface.

  18. Factors associated with interest in novel interfaces for upper limb prosthesis control.

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    Susannah M Engdahl

    Full Text Available Surgically invasive interfaces for upper limb prosthesis control may allow users to operate advanced, multi-articulated devices. Given the potential medical risks of these invasive interfaces, it is important to understand what factors influence an individual's decision to try one.We conducted an anonymous online survey of individuals with upper limb loss. A total of 232 participants provided personal information (such as age, amputation level, etc. and rated how likely they would be to try noninvasive (myoelectric and invasive (targeted muscle reinnervation, peripheral nerve interfaces, cortical interfaces interfaces for prosthesis control. Bivariate relationships between interest in each interface and 16 personal descriptors were examined. Significant variables from the bivariate analyses were then entered into multiple logistic regression models to predict interest in each interface.While many of the bivariate relationships were significant, only a few variables remained significant in the regression models. The regression models showed that participants were more likely to be interested in all interfaces if they had unilateral limb loss (p ≤ 0.001, odds ratio ≥ 2.799. Participants were more likely to be interested in the three invasive interfaces if they were younger (p < 0.001, odds ratio ≤ 0.959 and had acquired limb loss (p ≤ 0.012, odds ratio ≥ 3.287. Participants who used a myoelectric device were more likely to be interested in myoelectric control than those who did not (p = 0.003, odds ratio = 24.958.Novel prosthesis control interfaces may be accepted most readily by individuals who are young, have unilateral limb loss, and/or have acquired limb loss However, this analysis did not include all possible factors that may have influenced participant's opinions on the interfaces, so additional exploration is warranted.

  19. Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis.

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    Schiefer, Matthew; Tan, Daniel; Sidek, Steven M; Tyler, Dustin J

    2016-02-01

    Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject's sense of embodiment with a survey and his self-confidence. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

  20. Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis

    Science.gov (United States)

    Schiefer, Matthew; Tan, Daniel; Sidek, Steven M.; Tyler, Dustin J.

    2016-02-01

    Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Approach. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject’s sense of embodiment with a survey and his self-confidence. Main results. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Significance. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

  1. EFFECT OF POSTURAL CORRECTION WITH DIFFERENT TAPING MATERIALS ON SCAPULAR KINEMATICS AND MYOELECTRIC ACTIVITIES OF SCAPULAR ROTATORS IN SUBACROMIAL IMPINGEMENT SYNDROME A RANDOMIZED PLACEBO-CONTROLLED TRIAL

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    Eman Mohamad Abd Al-Gawad

    2016-06-01

    Full Text Available Background: Rigid and kinesio tapings are commonly used in the rehabilitation of subacromial impingement syndrome (SIS. Yet; the effect of postural correction with the two taping materials in SIS has not been extensively studied. The purpose of the study is to examine the effect of postural correction with two different taping materials on scapular kinematics and electromyography of scapular upward rotators in patients with SIS. Methods: Twenty female patients with SIS participated in this study. Their age ranged from 30-60 years. Participants were randomly assigned into: Group I (Kinesio tape, n=10 and Group II (rigid tape, n=10. Thoracic and scapular taping with posture correction was applied to both groups. Scapular upward rotation at 0˚, 60˚, 90˚ and 120˚ of shoulder elevation and the activity level of the upper fibers of trapezius (UT, lower fibers of trapezius (LT and serratus anterior (SA muscles were measured before and immediately after taping application. Results: Both taping materials significantly increased scapular upward rotation at 60°, 90° and 120° angles (P =.004,.002 and .047 respectively after the application of tape as compared to the before. In addition, significantly greater muscle activity of the LT and SA muscles (P =.027 and 0.05 respectively were demonstrated by the kinesio-taping group as compared to rigid taping group during real taping condition. Conclusion: Both taping materials are effective in restoring scapular kinematics. Furthermore, kinesio taping has a facilitatory effect on the LT and SA muscles. Kinesio taping may be considered an alternative to rigid taping in patients with SIS.

  2. Feasibility and repeatability of localized (31) P-MRS four-angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T.

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    Tušek Jelenc, Marjeta; Chmelík, Marek; Bogner, Wolfgang; Krššák, Martin; Trattnig, Siegfried; Valkovič, Ladislav

    2016-01-01

    Phosphorus ((31) P) MRS, combined with saturation transfer (ST), provides non-invasive insight into muscle energy metabolism. However, even at 7 T, the standard ST method with T1 (app) measured by inversion recovery takes about 10 min, making it impractical for dynamic examinations. An alternative method, i.e. four-angle saturation transfer (FAST), can shorten the examination time. The aim of this study was to test the feasibility, repeatability, and possible time resolution of the localized FAST technique measurement on an ultra-high-field MR system, to accelerate the measurement of both Pi -to-ATP and PCr-to-ATP reaction rates in the human gastrocnemius muscle and to test the feasibility of using the FAST method for dynamic measurements. We measured the exchange rates and metabolic fluxes in the gastrocnemius muscle of eight healthy subjects at 7 T with the depth-resolved surface coil MRS (DRESS)-localized FAST method. For comparison, a standard ST localized method was also used. The measurement time for the localized FAST experiment was 3.5 min compared with the 10 min for the standard localized ST experiment. In addition, in five healthy volunteers, Pi -to-ATP and PCr-to-ATP metabolic fluxes were measured in the gastrocnemius muscle at rest and during plantar flexion by the DRESS-localized FAST method. The repeatability of PCr-to-ATP and Pi -to-ATP exchange rate constants, determined by the slab-selective localized FAST method at 7 T, is high, as the coefficients of variation remained below 20%, and the results of the exchange rates measured with the FAST method are comparable to those measured with standard ST. During physical activity, the PCr-to-ATP metabolic flux decreased (from FCK  = 8.21 ± 1.15 mM s(-1) to FCK  = 3.86 ± 1.38 mM s(-1) ) and the Pi -to-ATP flux increased (from FATP  = 0.43 ± 0.14 mM s(-1) to FATP  = 0.74 ± 0.13 mM s(-1) ). In conclusion, we could demonstrate that measurements

  3. Combining two open source tools for neural computation (BioPatRec and Netlab) improves movement classification for prosthetic control.

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    Prahm, Cosima; Eckstein, Korbinian; Ortiz-Catalan, Max; Dorffner, Georg; Kaniusas, Eugenijus; Aszmann, Oskar C

    2016-08-31

    Controlling a myoelectric prosthesis for upper limbs is increasingly challenging for the user as more electrodes and joints become available. Motion classification based on pattern recognition with a multi-electrode array allows multiple joints to be controlled simultaneously. Previous pattern recognition studies are difficult to compare, because individual research groups use their own data sets. To resolve this shortcoming and to facilitate comparisons, open access data sets were analysed using components of BioPatRec and Netlab pattern recognition models. Performances of the artificial neural networks, linear models, and training program components were compared. Evaluation took place within the BioPatRec environment, a Matlab-based open source platform that provides feature extraction, processing and motion classification algorithms for prosthetic control. The algorithms were applied to myoelectric signals for individual and simultaneous classification of movements, with the aim of finding the best performing algorithm and network model. Evaluation criteria included classification accuracy and training time. Results in both the linear and the artificial neural network models demonstrated that Netlab's implementation using scaled conjugate training algorithm reached significantly higher accuracies than BioPatRec. It is concluded that the best movement classification performance would be achieved through integrating Netlab training algorithms in the BioPatRec environment so that future prosthesis training can be shortened and control made more reliable. Netlab was therefore included into the newest release of BioPatRec (v4.0).

  4. Wireless radio channel for intramuscular electrode implants in the control of upper limb prostheses.

    Science.gov (United States)

    Stango, Antonietta; Yazdandoost, Kamya Yekeh; Farina, Dario

    2015-01-01

    In the last few years the use of implanted devices has been considered also in the field of myoelectric hand prostheses. Wireless implanted EMG (Electromyogram) sensors can improve the functioning of the prosthesis, providing information without the disadvantage of the wires, and the usability by amputees. The solutions proposed in the literature are based on proprietary communication protocols between the implanted devices and the prosthesis controller, using frequency bands that are already assigned to other purposes. This study proposes the use of a standard communication protocol (IEEE 802.15.6), specific for wireless body area networks (WBANs), which assign a specific bandwidth to implanted devices. The propagation losses from in-to-on body were investigated by numerical simulation with a 3D human model and an electromagnetic solver. The channel model resulting from the study represents the first step towards the development of myoelectric prosthetic hands which are driven by signals acquired by implanted sensors. However these results can provide important information to researchers for further developments, and manufacturers, which can decrease the production costs for hand prostheses having a common standard of communication with assigned frequencies of operation.

  5. Controlling

    OpenAIRE

    Hriňáková, Daniela

    2014-01-01

    The topic of my diploma thesis is controlling. The first part is theoretical where I describe the history, meaning and functions of controlling. After that I also specify the methods of strategical, operational and cost controlling. The practical part applied method of controlling to the selected company. The aim of this study is to determine the benefits of controlling for the company. At the operational level it describes the process of controlling in the firm and there are given suggestion...

  6. EFFECTS OF ELECTRIC STIMULATION ON THE HEALING OF TENDON OF THE GASTROCNEMIUS MUSCLE IN RABBITS (Oryctolagus cunicullus EFEITOS DA ESTIMULAÇÃO ELÉTRICA NA CICATRIZAÇÃO DO TENDÃO DO MÚSCULO GASTROCNÊMIO EM COELHOS (Oryctolagus cunicullus

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    Weslay Souza de Oliveira

    2009-09-01

    Full Text Available The aim of this study was to evaluate the effect of transcutaneous electrical stimulation with alternate electrical current on gastrocnemius muscle tendon healing, in rabbits submitted to experimental tenotomy and tenorrhaphy. Twenty-four male rabbits, New Zealand breed, were divided into four groups of the same number, in order to evaluate the cicatricial tendon repair at 7, 15, 21 and 30 days post-surgery. The middle third of the tendon of the gastocnemius muscle was sectioned transversall and submitted to a synthesis with Kessler modified suture. After 24 hours, daily at the same schedule, were done near the cutaneous wound of the right pelvic member, applications of 2 mA of alternative current, during six minutes, at a frequence of 100 Hz. The material collected was examined by light microscopy. Significant difference wasn´t found between the treated member and the control. Transcutaneous electrotherapy was used in our experimental protocol, despite not leading to tissue damage and being less invasive in comparison to other methods, was incapable to promote a more efficient healing response on the gastrocnemius muscle tendon repair in rabbits.

    KEY WORDS: Achilles tendon, electrotherapy, surgery, tenotomy, tissue repair. Este trabalho teve como objetivo avaliar o efeito da estimulação elétrica transcutânea de corrente alternada na regeneração do tendão do músculo gastrocnêmio, em coelhos submetidos à tenotomia e tenorrafia experimental. Dividiram-se vinte e quatro coelhos adultos da raça Nova Zelândia em quatro grupos iguais para avaliação da cicatrização tendínea aos sete, quinze, vinte e um e trinta dias de pós-operatório. Após incisão cutânea de aproximadamente três centímetros, o terço médio do tendão do músculo gastrocnêmio foi individualizado, seccionado transversalmente e suturado com sutura de Kessler modificada. Decorridas 24 horas, diariamente em um mesmo horário aplicaram-se, próxima

  7. Central motor control failure in fibromyalgia: a surface electromyography study.

    Science.gov (United States)

    Casale, Roberto; Sarzi-Puttini, Piercarlo; Atzeni, Fabiola; Gazzoni, Marco; Buskila, Dan; Rainoldi, Alberto

    2009-07-01

    Fibromyalgia (FM) is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Eight female patients aged 55.6 +/- 13.6 years (FM group) and eight healthy female volunteers aged 50.3 +/- 9.3 years (MCG) were studied by means of non-invasive surface electromyography (s-EMG) involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited) contractions. Maximal voluntary contractions (MVCs), motor unit action potential conduction velocity distributions (mean +/- SD and skewness), and the mean power frequency of the spectrum (MNF) were estimated in order to assess whether there were any significant differences between the two groups and contraction types. The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 +/- 0.052%/s in FM vs -0.196 +/- 0.133%/s in MCG; normalised MNF rate of changes: -0.29 +/- 0.16%/s in FM vs -0.66 +/- 0.34%/s in MCG). Mean conduction velocity distribution and skewnesses values were higher (p fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered suprasegmental control.

  8. Central motor control failure in fibromyalgia: a surface electromyography study

    Science.gov (United States)

    Casale, Roberto; Sarzi-Puttini, Piercarlo; Atzeni, Fabiola; Gazzoni, Marco; Buskila, Dan; Rainoldi, Alberto

    2009-01-01

    Background Fibromyalgia (FM) is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Methods Eight female patients aged 55.6 ± 13.6 years (FM group) and eight healthy female volunteers aged 50.3 ± 9.3 years (MCG) were studied by means of non-invasive surface electromyography (s-EMG) involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited) contractions. Maximal voluntary contractions (MVCs), motor unit action potential conduction velocity distributions (mean ± SD and skewness), and the mean power frequency of the spectrum (MNF) were estimated in order to assess whether there were any significant differences between the two groups and contraction types. Results The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 ± 0.052%/s in FM vs -0.196 ± 0.133%/s in MCG; normalised MNF rate of changes: -0.29 ± 0.16%/s in FM vs -0.66 ± 0.34%/s in MCG). Mean conduction velocity distribution and skewnesses values were higher (p fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered suprasegmental control. PMID:19570214

  9. An implementation of movement classification for prosthesis control using custom-made EMG system

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    Mejić Luka

    2017-01-01

    Full Text Available Electromyography (EMG is a well known technique used for recording electrical activity produced by human muscles. In the last few decades, EMG signals are used as a control input for prosthetic hands. There are several multifunctional myoelectric prosthetic hands for amputees on the market, but so forth, none of these devices permits the natural control of more than two degrees of freedom. In this paper we present our implementation of the pattern classification using custom made components (electrodes and an embedded EMG amplifier. The components were evaluated in offline and online tests, in able bodied as well as amputee subjects. This type of control is based on computing the time domain features of the EMG signals recorded from the forearm and using these features as input for a Linear Discriminant Analysis (LDA classifier estimating the intention of the prosthetic user. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III - 41007

  10. Embedded System for Prosthetic Control Using Implanted Neuromuscular Interfaces Accessed Via an Osseointegrated Implant.

    Science.gov (United States)

    Mastinu, Enzo; Doguet, Pascal; Botquin, Yohan; Hakansson, Bo; Ortiz-Catalan, Max

    2017-08-01

    Despite the technological progress in robotics achieved in the last decades, prosthetic limbs still lack functionality, reliability, and comfort. Recently, an implanted neuromusculoskeletal interface built upon osseointegration was developed and tested in humans, namely the Osseointegrated Human-Machine Gateway. Here, we present an embedded system to exploit the advantages of this technology. Our artificial limb controller allows for bioelectric signals acquisition, processing, decoding of motor intent, prosthetic control, and sensory feedback. It includes a neurostimulator to provide direct neural feedback based on sensory information. The system was validated using real-time tasks characterization, power consumption evaluation, and myoelectric pattern recognition performance. Functionality was proven in a first pilot patient from whom results of daily usage were obtained. The system was designed to be reliably used in activities of daily living, as well as a research platform to monitor prosthesis usage and training, machine-learning-based control algorithms, and neural stimulation paradigms.

  11. Avaliação das propriedades mecânicas do músculo gastrocnêmio de ratas imobilizado e submetido à corrente russa Mechanical property analysis of the gastrocnemius muscle of rats immobilized and submitted to the russian current

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    Douglas Reis Abdalla

    2009-03-01

    Full Text Available A eletroestimulação neuromuscular por corrente russa, recurso utilizado na reabilitação, pode aumentar o trofismo e restabelecer a força muscular, sobretudo dos músculos que apresentam deficit pós-imobilização, como é o caso de lesões durante a prática esportiva. Objetivou-se avaliar as propriedades mecânicas do músculo gastrocnêmio de ratas imobilizadas por 14 dias e posteriormente submetidas à eletroestimulação por corrente russa durante 10 dias. Utilizaram-se 32 ratas Wistar divididas em quatro grupos: controle (G1, imobilizado (G2; imobilizado e liberado por 10 dias (G3 e imobilizado e submetido à corrente russa por 10 dias (G4. A avaliação das propriedades mecânicas - carga, alongamento, rigidez e resiliência - foi feita por ensaio de tração longitudinal. Quanto à carga no limite máximo, o G4 apresentou valores mais elevados quando comparado ao grupo apenas imobilizado (G2, pNeuromuscular electric stimulation by Russian current, used in rehabilitation, is able to increase muscle trophism and strength, especially in muscles with post-immobilization deficit, as is the case of injuries during sports practice. The purpose here was to assess the gastrocnemius muscle mechanical properties of rats immobilized for 14 days and subjected to electric stimulation by Russian current for 10 days. Thirty two Wistar female rats were divided into four groups: control (G1, immobilized (G2, immobilized and freed (G3, and immobilized and afterwards submitted to Russian current (G4. Mechanical properties - maximum load and stretch, stiffness, and resilience - were assessed by longitudinal traction. As to maximum load, G4 showed higher values when compared to the only-immobilized group (G2, p<0.001, though not attaining G1 values. In the analysis of maximum elongation results, G3 and G4 presented significantly higher values than G2 (p<0.001. Concerning stiffness, only G2 reached higher values (p<0.05 than G1. As to resilience, G4

  12. Combining human volitional control with intrinsic controller on robotic prosthesis: A case study on adaptive slope walking.

    Science.gov (United States)

    Chen, Baojun; Wang, Qining

    2015-01-01

    Affording lower-limb amputees the ability to volitionally control robotic prostheses can improve the adaptability to terrain changes as well as enhancing proprioception. However, it also increases amputees' conscious burdens for prosthesis control. Therefore, in this paper, we aim to propose a hybrid controller which combines human volitional control with the intrinsic controller on the robotic transtibial prosthesis, enabling the amputee actively controlling prosthesis with little conscious attention. In this preliminary study, a hybrid controller for adaptive slope walking was designed. A slope estimator was embedded in the intrinsic controller to estimate the ground slope of the previous step using signals measured by prosthetic sensors. And a myoelectric controller allows the amputee subject to convey slope changes to prosthetic controller by volitionally contract his residual muscles, whose electromyography signals were mapped to the slope increment. The hybrid controller combined these two results to obtain the estimated slope. One male transtibial amputee subject was recruited in this research. Experiment results showed that the intrinsic slope estimator produced satisfactory estimation results with an average absolute error of 0.70 ± 0.54 degrees. By adding amputee's volitional control, the hybrid controller is able to predict the upcoming slope changes.

  13. Effect of carnitine supplementation on fatigue level in the gastrocnemius muscle of trained and sedentary rats. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p324

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    Fabio Pinhero Ramos

    2012-05-01

    Full Text Available L-carnitine, considered to be of great value in metabolic processes, plays an important role in the mitochondrial β-oxidation process. It may be used to improve athletic performance and to maintain a higher workload during exercise. This study aimed to investigate the effect of L-carnitine supplementation on muscle fatigue in sciatic nerve-gastrocnemius muscle preparations in sedentary and trained rats. The animals were divided into 4 groups: non-supplemented sedentary (NSS, supplemented sedentary (SS, non-supplemented trained (NST, and supplemented trained (ST rats. The animals were trained in daily 1-h sessions (5 days/week and received chronic oral L-carnitine supplementation (1 mg/mL for 4 weeks. Muscle fatigue was determined by supramaximal tetanic stimulation of the sciatic nerve (50 Hz. Time values for strength reduction were significantly different (p<0.05 between NSS vs. SS and NST vs. ST rats. No significant differences were observed between SS vs. ST and NST vs. NSS rats. These findings demonstrate that L-carnitine lengthen the time required for induction of muscle fatigue.

  14. Dual window pattern recognition classifier for improved partial-hand prosthesis control

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    Eric Joseph Earley

    2016-02-01

    Full Text Available Although partial-hand amputees largely retain the ability to use their wrist, it is difficult to preserve wrist motion while using a myoelectric partial-hand prosthesis without severely impacting control performance. Electromyogram (EMG pattern recognition is a well-studied control method; however, EMG from wrist motion can obscure myoelectric finger control signals. Thus, to accommodate wrist motion and to provide high classification accuracy and minimize system latency, we developed a training protocol and a classifier that switches between long and short EMG analysis window lengths.Seventeen non-amputee and two partial-hand amputee subjects participated in a study to determine the effects of including EMG from different arm and hand locations during static and/or dynamic wrist motion in the classifier training data. We evaluated several real-time classification techniques to determine which control scheme yielded the highest performance in virtual real-time tasks using a 3-way ANOVA. We found significant interaction between analysis window length and the number of grasps available. Including static and dynamic wrist motion and intrinsic hand muscle EMG with extrinsic muscle EMG significantly reduced pattern recognition classification error by 35%. Classification delay or majority voting techniques significantly improved real-time task completion rates (17%, selection (23% and completion (11% times, and selection attempts (15% for non-amputee subjects, and the dual window classifier significantly reduced the time (8% and average number of attempts required to complete grasp selections (14% made in various wrist positions. Amputee subjects demonstrated improved task timeout rates, and made fewer grasp selection attempts, with classification delay or majority voting techniques.Thus, the proposed techniques show promise for improving control of partial-hand prostheses and more effectively restoring function to individuals using these devices.

  15. Controlling a virtual forehand prosthesis using an adaptive and affective Human-Machine Interface.

    Science.gov (United States)

    Rezazadeh, I Mohammad; Firoozabadi, S M P; Golpayegani, S M R Hashemi; Hu, H

    2011-01-01

    This paper presents the design of an adaptable Human-Machine Interface (HMI) for controlling virtual forearm prosthesis. Direct physical performance measures (obtained score and completion time) for the requested tasks were calculated. Furthermore, bioelectric signals from the forehead were recorded using one pair of electrodes placed on the frontal region of the subject head to extract the mental (affective) measures while performing the tasks. By employing the proposed algorithm and above measures, the proposed HMI can adapt itself to the subject's mental states, thus improving the usability of the interface. The quantitative results from 15 subjects show that the proposed HMI achieved better physical performance measures in comparison to a conventional non-adaptive myoelectric controller (p < 0.001).

  16. Elevated gastrocnemius forces compensate for decreased hamstrings forces during the weight-acceptance phase of single-leg jump landing: implications for anterior cruciate ligament injury risk.

    Science.gov (United States)

    Morgan, Kristin D; Donnelly, Cyril J; Reinbolt, Jeffrey A

    2014-10-17

    Approximately 320,000 anterior cruciate ligament (ACL) injuries in the United States each year are non-contact injuries, with many occurring during a single-leg jump landing. To reduce ACL injury risk, one option is to improve muscle strength and/or the activation of muscles crossing the knee under elevated external loading. This study's purpose was to characterize the relative force production of the muscles supporting the knee during the weight-acceptance (WA) phase of single-leg jump landing and investigate the gastrocnemii forces compared to the hamstrings forces. Amateur male Western Australian Rules Football players completed a single-leg jump landing protocol and six participants were randomly chosen for further modeling and simulation. A three-dimensional, 14-segment, 37 degree-of-freedom, 92 muscle-tendon actuated model was created for each participant in OpenSim. Computed muscle control was used to generate 12 muscle-driven simulations, 2 trials per participant, of the WA phase of single-leg jump landing. A one-way ANOVA and Tukey post-hoc analysis showed both the quadriceps and gastrocnemii muscle force estimates were significantly greater than the hamstrings (p<0.001). Elevated gastrocnemii forces corresponded with increased joint compression and lower ACL forces. The elevated quadriceps and gastrocnemii forces during landing may represent a generalized muscle strategy to increase knee joint stiffness, protecting the knee and ACL from external knee loading and injury risk. These results contribute to our understanding of how muscle's function during single-leg jump landing and should serve as the foundation for novel muscle-targeted training intervention programs aimed to reduce ACL injuries in sport. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Development of regenerative peripheral nerve interfaces for motor control of neuroprosthetic devices

    Science.gov (United States)

    Kemp, Stephen W. P.; Urbanchek, Melanie G.; Irwin, Zachary T.; Chestek, Cynthia A.; Cederna, Paul S.

    2017-05-01

    Traumatic peripheral nerve injuries suffered during amputation commonly results in debilitating neuropathic pain in the affected limb. Modern prosthetic technologies allow for intuitive, simultaneous control of multiple degrees of freedom. However, these state-of-the-art devices require separate, independent control signals for each degree of freedom, which is currently not possible. As a result, amputees reject up to 75% of myoelectric devices preferring instead to use body-powered artificial limbs which offer subtle sensory feedback. Without meaningful and intuitive sensory feedback, even the most advanced myoelectric prostheses remain insensate, burdensome, and are associated with enormous cognitive demand and mental fatigue. The ideal prosthetic device is one which is capable of providing intuitive somatosensory feedback essential for interaction with the environment. Critical to the design of such a bioprosthetic device is the development of a reliable biologic interface between human and machine. This ideal patient-prosthetic interface allows for transmission of both afferent somatosensory information and efferent motor signals for a closed-loop feedback system of neural control. Our lab has developed the Regenerative Peripheral Nerve Interface (RPNI) as a biologic nerve interface designed for stable integration of a prosthetic device with transected peripheral nerves in a residual limb. The RPNI is constructed by surgically implanting the distal end of a transected peripheral nerve into an autogenous muscle graft. Animal experiments in our lab have shown recording of motor signals from RPNI's implanted into both rodents and monkeys. Here, we achieve high amplitude EMG signals with a high signal to noise (SNR) ratio.

  18. Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans.

    Science.gov (United States)

    Makihara, Yukiko; Segal, Richard L; Wolpaw, Jonathan R; Thompson, Aiko K

    2014-09-15

    In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion. Copyright © 2014 the American Physiological Society.

  19. KOMBINASI LATIHAN EKSENTRIK M.GASTROCNEMIUS DAN LATIHAN PLYOMETRIC LEBIH BAIK DARI PADA LATIHAN EKSENTRIK M.QUADRICEPS DAN LATIHAN PLYOMETRIC TERHADAP PENINGKATAN AGILITY PADA MAHASISWA DI UNIVERSITAS ESA UNGGUL

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    Miranti Yolanda Anggita

    2015-08-01

    Full Text Available Increase agility for students is determined by muscular strength, speed, and flexibility. The ability of muscles to contract quickly will increase the speed of muscle in motion. Increase in speed, strength and flexibility of muscles due to stretch muscle-tendinous unit. The mechanism become the basis for moving in the shortest possible time. Agility on student issues has not received much attention, the attention of the agility found better in many athletes. This research is an experimental study to analysis at the difference between the intervention of with gastrocmineus muscle eccentric exercises and plyometric exercises with eccentric exercise quadriceps muscle and plyometric to increase agility on students at the University of Esa Unggul. A total of 40 students aged 18-21 years old who meet the criteria inclusion were randomly divided into 2 treatment groups. The old treatment group I was given quadriceps muscle eccentric and plyometric treatment group II eccentric exercise gastrocmineus muscle and plyometric exercises. Both exercise was done 3 times was given per week for 6 weeks. Agility is measured by Right-Boomerang Run Test. The results of the hypothesis testing using t-test related and different mean values obtained agility treatment group I (16,43±0.89secon and a second treatment group (16,01± 1,04seconwith p?0.05. Conclusion of the study is a combination of eccentric exercise m.gastrocnemius with plyometric exercise no better than the m.quadriceps eceentric exercises with plyometric exercises to increase agility on student at Esa Unggul University.

  20. Reliability and validity of a dual-probe personal computer-based muscle viewer for measuring the pennation angle of the medial gastrocnemius muscle in patients who have had a stroke.

    Science.gov (United States)

    Cho, Ji-Eun; Cho, Ki Hun; Yoo, Jun Sang; Lee, Su Jin; Lee, Wan-Hee

    2018-01-01

    Background A dual-probe personal computer-based muscle viewer (DPC-BMW) is advantageous in that it is relatively lightweight and easy to apply. Objective To investigate the reliability and validity of the DPC-BMW in comparison with those of a portable ultrasonography (P-US) device for measuring the pennation angle of the medial gastrocnemius (MG) muscle at rest and during contraction. Methods Twenty-four patients who had a stroke (18 men and 6 women) participated in this study. Using the DPC-BMW and P-US device, the pennation angle of the MG muscle on the affected side was randomly measured. Two examiners randomly obtained the images of all the participants in two separate test sessions, 7 days apart. Intraclass correlation coefficient (ICC), confidence interval, standard error of measurement, Bland-Altman plot, and Pearson correlation coefficient were used to estimate their reliability and validity. Results The ICC for the intrarater reliability of the MG muscle pennation angle measured using the DPC-BMW was > 0.916, indicating excellent reliability, and that for the interrater reliability ranged from 0.964 to 0.994. The P-US device also exhibited good reliability. A high correlation was found between the measurements of MG muscle pennation angle obtained using the DPC-BMW and that obtained using the P-US device (p < 0.01). Conclusion The DPC-BMW can provide clear images for accurate measurements, including measurements using dual probes. It has the advantage of rehabilitative US imaging for individuals who have had a stroke. More research studies are needed to evaluate the usefulness of the DPC-BMW in rehabilitation.

  1. Early-age feed restriction affects viability and gene expression of satellite cells isolated from the gastrocnemius muscle of broiler chicks

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    Li Yue

    2012-11-01

    Full Text Available Abstract Background Muscle growth depends on the fusion of proliferate satellite cells to existing myofibers. We reported previously that 0–14 day intermittent feeding led to persistent retardation in myofiber hypertrophy. However, how satellite cells respond to such nutritional insult has not been adequately elucidated. Results One-day-old broiler chicks were allocated to control (Con, ad libitum feeding, intermittent feeding (IF, feed provided on alternate days and re-feeding (RF, 2 days ad libitum feeding after 12 days of intermittent feeding groups. Chickens were killed on Day 15 and satellite cells were isolated. When cultured, satellite cells from the IF group demonstrated significant retardation in proliferation and differentiation potential, while RF partly restored the proliferation rate and differentiation potential of the satellite cells. Significant up-regulation of insulin like growth factor I receptor (IGF-IR (P0.05 and thyroid hormone receptor α (TRα (P0.05, and down-regulation of growth hormone receptor (GHR (P0.01 and IGF-I (P0.01 mRNA expression was observed in freshly isolated IF satellite cells when compared with Con cells. In RF cells, the mRNA expression of IGF-I was higher (P0.05 and of TRα was lower (P0.01 than in IF cells, suggesting that RF restored the mRNA expression of TRα and IGF-I, but not of GHR and IGF-IR. The Bax/Bcl-2 ratio tended to increase in the IF group, which was reversed in the RF group (P0.05, indicating that RF reduced the pro-apoptotic influence of IF. Moreover, no significant effect of T3 was detected on cell survival in IF cells compared with Con (PP0.05 cells. Conclusions These data suggest that early-age feed restriction inhibits the proliferation and differentiation of satellite cells, induces changes in mRNA expression of the GH/IGF-I and thyroid hormone receptors in satellite cells, as well as blunted sensitivity of satellite cells to T3, and that RF partially reverses these effects. Thus

  2. Estudo morfológico no músculo gastrocnêmio de camundongos C57 BL10 submetidos à ingestão prolongada de etanol Study of ultrastructural alterations in gastrocnemius muscle of C57 BL10 mice after prolonged ethanol ingestion

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    João Batista Guedes e Silva

    1996-06-01

    foi vista no citoplasma dos hepatócitos parecendo constituir uma evidência a mais da ação tóxica do etanol sobre o organismo. Concluímos que a ingestão prolongada de etanol, representando 14,4% de calorias totais, produz no músculo gastrocnêmio de camundongos C57BL10 bem nutridos um elenco de alterações ultraestruturais que refletem um efeito tóxico direto sobre o músculo esquelético. As alterações constatadas são semelhantes àquelas descritas na miopatia alcoólica crônica humanaThe effects of chronic alcoholism on gastrocnemius muscle of well-nourished mice were morphologically studied to test the direct toxic role of ethanol on skeletal muscle. Thirty male young adult C57BL10 mice were divided in two groups: Group A (control consisting of ten mice that drank water and Group B (alcoholic consisting of twenty mice that drank 25% ethanol. All mice were allowed a balanced laboratory chow. The animals were kept on this ad libitum regimen under the same conditions of environment for 48 weeks and were weighed once a week. The daily dietary consumption and caloric intake were estimated, the animals having had a substantial weight gain, showing no signs of malnutrition. At the end of the experiment the animals were killed for morphological studies. No abnormalities were observed by conventional microscopy.Striking deviations from normal were verified by electron microscopy in all specimens. Dilatation of sarcoplasmic reticulum was a common feature, sometimes resulting in the formation of large vesicles and involving the terminal cisternae with the displacement of the triads. Areas of narrowing, splitting and loss of myofibrils were seen. Zones of complete disorganization of miofibrils could be occasionally observed. Mitochondria were generally normal. Peculiar tubular aggregates seen commonly in periodic paralysis and other human pathological conditions, were encountered in both control and alcoholic mice. Intramuscular nerves and neuromuscular junctions

  3. Employing 3D virtual reality games to develop ANN for device control: a pilot study.

    Science.gov (United States)

    Patterson, P E

    2001-01-01

    Non-immersive virtual reality (VR) game scenarios were developed to aid in the collection of EMG parameters from the biceps and triceps while subjects performed a sequenced series of tasks in the virtual environment. For each subject the best ANN configuration (combination of hidden layers and transfer functions) was chosen, with the resulting optimized algorithms used to classify the sequence of contractions and the function type of the subjects while playing new game scenarios. The wide variety of individually configured ANN developed show why it is difficult to train new users of myoelectric devices with a single algorithm. The use of VR-based games shows promise as a training technique for individuals needing to develop control for prosthetic limbs.

  4. Energetics of anaerobic glycolysis in dog gastrocnemius.

    Science.gov (United States)

    di Prampero, P E; Meyer, M; Cerretelli, P; Piiper, J

    1978-10-18

    Thermally isolated gastrocnemii were stimulated to exhaustion, by rhythmic isotonic (70 N) tetanic contractions, during complete occlusion of blood flow. Enthalpy change (h = work + heat) and work output (w) (kJ/kg) were obtained from records of deep muscle temperature and shortening. The lactate produced (LA, mol/kg) was measured in the outflow after reestablishement of blood flow. The following relationships were obtained: h = 76LA + 1.2, and w = 19.8LA + 0.30. As the energy liberated at exhaustion by alactic energy sources (approximately P and O2 stores) is constant, deltah/deltaLA = 76 (+/- 10.5; S.E.) kJ/mol is the enthalpy change for lactate formation (delta HLA). The neutralization heat was estimated on muscle homogenates at 12kJ/mol, leaving approximately 64 kJ/MOL for deltaH of LA formation proper. The mechanical efficiencies of work related to LA formation (ELA) and of that not related to LA formation (EnonLA) were practically identical (0.25). From these values and from deltaHLA, the enthalpy change of approximately P splitting was estimated in the range of 52--62kJ/mol, depending on the value of the ratio delta approximately P/deltaLA assumed in the calculation.

  5. Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

    Science.gov (United States)

    2012-01-01

    Background Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user’s nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. Methods We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. Results We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Conclusion Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee’s nervous system. PMID:22882763

  6. Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

    Directory of Open Access Journals (Sweden)

    Huang Stephanie

    2012-08-01

    Full Text Available Abstract Background Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user’s nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. Methods We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. Results We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Conclusion Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee’s nervous system.

  7. Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface.

    Science.gov (United States)

    Huang, Stephanie; Ferris, Daniel P

    2012-08-10

    Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user's nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee's nervous system.

  8. Estimulação elétrica neuromuscular e o alongamento passivo manual na recuperação das propriedades mecânicas do músculo gastrocnêmio imobilizado Neuromuscular electric stimulation and manual passive stretching when recovering mechanical properties of immobilized gastrocnemius muscles

    Directory of Open Access Journals (Sweden)

    Leonardo César Carvalho

    2008-01-01

    Full Text Available Avaliamos a influência da imobilização, remobilização livre, remobilização com alongamento passivo manual, remobilização com estimulação elétrica neuromuscular (NMES e remobilização por NMES e alongamento passivo manual associados sobre algumas propriedades mecânicas do músculo gastrocnêmio de ratas. Foram avaliadas 60 ratas divididas em seis grupos.Um destes grupos foi usado como controle. Todos os outros grupos tiveram o membro posterior direito imobilizado por 14 dias consecutivos. Destes grupos um foi imobilizado e em seguida avaliado, um foi liberado da imobilização e permaneceu nas gaiolas plásticas por 10 dias, outro foi submetido a técnica de alongamento passivo manual por 10 dias consecutivos, outro foi submetido a NMES por 10 dias consecutivos e o último foi submetido a NMES somado ao alongamento passivo manual por 10 dias consecutivos. Observamos que a imobilização reduziu os valores das propriedades mecânicas avaliadas no músculo. A remobilização livre não restabeleceu nenhuma das propriedades avaliadas. A remobilização por alongamento passivo manual devolveu ao músculo as propriedades de alongamento no limite de proporcionalidade, rigidez e resiliência. A remobilização estimulada por NMES restabeleceu todas as propriedades estudadas. A remobilização por NMES somada ao alongamento passivo restabeleceu as propriedades mecânicas de alongamento no limite máximo e de proporcionalidade e rigidez.We evaluated the influence of immobilization, free remobilization, remobilization with manual passive stretching, remobilization with neuromuscular electric stimulation (NMES and remobilization with electric stimulation and associated passive stretching on some mechanical properties of the gastrocnemius muscle of female rats. Sixty female rats were assessed, being distributed into 6 experimental groups. One of these groups served as control. The animals of the five remaining groups had their right posterior

  9. Co-contraction patterns of trans-tibial amputee ankle and knee musculature during gait

    Science.gov (United States)

    2012-01-01

    Background Myoelectric control of upper extremity powered prostheses has been used clinically for many years, however this approach has not been fully developed for lower extremity prosthetic devices. With the advent of powered lower extremity prosthetic components, the potential role of myoelectric control systems is of increasing importance. An understanding of muscle activation patterns and their relationship to functional ambulation is a vital step in the future development of myoelectric control. Unusual knee muscle co-contractions have been reported in both limbs of trans-tibial amputees. It is currently unknown what differences exist in co-contraction between trans-tibial amputees and controls. This study compares the activation and co-contraction patterns of the ankle and knee musculature of trans-tibial amputees (intact and residual limbs), and able-bodied control subjects during three speeds of gait. It was hypothesized that residual limbs would have greater ankle muscle co-contraction than intact and able-bodied control limbs and that knee muscle co-contraction would be different among all limbs. Lastly it was hypothesized that the extent of muscle co-contraction would increase with walking speed. Methods Nine unilateral traumatic trans-tibial amputees and five matched controls participated. Surface electromyography recorded activation from the Tibialis Anterior, Medial Gastrocnemius, Vastus Lateralis and Biceps Femoris of the residual, intact and control limbs. A series of filters were applied to the signal to obtain a linear envelope of the activation patterns. A co-contraction area (ratio of the integrated agonist and antagonist activity) was calculated during specific phases of gait. Results Co-contraction of the ankle muscles was greater in the residual limb than in the intact and control limbs during all phases of gait. Knee muscle co-contraction was greater in the residual limb than in the control limb during all phases of gait. Conclusion Co

  10. Co-contraction patterns of trans-tibial amputee ankle and knee musculature during gait

    Directory of Open Access Journals (Sweden)

    Seyedali Mahyo

    2012-05-01

    Full Text Available Abstract Background Myoelectric control of upper extremity powered prostheses has been used clinically for many years, however this approach has not been fully developed for lower extremity prosthetic devices. With the advent of powered lower extremity prosthetic components, the potential role of myoelectric control systems is of increasing importance. An understanding of muscle activation patterns and their relationship to functional ambulation is a vital step in the future development of myoelectric control. Unusual knee muscle co-contractions have been reported in both limbs of trans-tibial amputees. It is currently unknown what differences exist in co-contraction between trans-tibial amputees and controls. This study compares the activation and co-contraction patterns of the ankle and knee musculature of trans-tibial amputees (intact and residual limbs, and able-bodied control subjects during three speeds of gait. It was hypothesized that residual limbs would have greater ankle muscle co-contraction than intact and able-bodied control limbs and that knee muscle co-contraction would be different among all limbs. Lastly it was hypothesized that the extent of muscle co-contraction would increase with walking speed. Methods Nine unilateral traumatic trans-tibial amputees and five matched controls participated. Surface electromyography recorded activation from the Tibialis Anterior, Medial Gastrocnemius, Vastus Lateralis and Biceps Femoris of the residual, intact and control limbs. A series of filters were applied to the signal to obtain a linear envelope of the activation patterns. A co-contraction area (ratio of the integrated agonist and antagonist activity was calculated during specific phases of gait. Results Co-contraction of the ankle muscles was greater in the residual limb than in the intact and control limbs during all phases of gait. Knee muscle co-contraction was greater in the residual limb than in the control limb during all phases

  11. Electrotactile EMG feedback improves the control of prosthesis grasping force

    Science.gov (United States)

    Schweisfurth, Meike A.; Markovic, Marko; Dosen, Strahinja; Teich, Florian; Graimann, Bernhard; Farina, Dario

    2016-10-01

    Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for

  12. Natural control capabilities of robotic hands by hand amputated subjects.

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Caputo, Barbara; Muller, Henning

    2014-01-01

    People with transradial hand amputations who own a myoelectric prosthesis currently have some control capabilities via sEMG. However, the control systems are still limited and not natural. The Ninapro project is aiming at helping the scientific community to overcome these limits through the creation of publicly available electromyography data sources to develop and test machine learning algorithms. In this paper we describe the movement classification results gained from three subjects with an homogeneous level of amputation, and we compare them with the results of 40 intact subjects. The number of considered subjects can seem small at first sight, but it is not considering the literature of the field (which has to face the difficulty of recruiting trans-radial hand amputated subjects). The classification is performed with four different classifiers and the obtained balanced classification rates are up to 58.6% on 50 movements, which is an excellent result compared to the current literature. Successively, for each subject we find a subset of up to 9 highly independent movements, (defined as movements that can be distinguished with more than 90% accuracy), which is a deeply innovative step in literature. The natural control of a robotic hand in so many movements could lead to an immediate progress in robotic hand prosthetics and it could deeply change the quality of life of amputated subjects.

  13. Comparison of regional skeletal muscle tissue oxygenation in college athletes and sedentary control subjects using quantitative BOLD MR imaging.

    Science.gov (United States)

    Stacy, Mitchel R; Caracciolo, Christopher M; Qiu, Maolin; Pal, Prasanta; Varga, Tyler; Constable, Robert Todd; Sinusas, Albert J

    2016-08-01

    Blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging permits noninvasive assessment of tissue oxygenation. We hypothesized that BOLD imaging would allow for regional evaluation of differences in skeletal muscle oxygenation between athletes and sedentary control subjects, and dynamic BOLD responses to ischemia (i.e., proximal cuff occlusion) and reactive hyperemia (i.e., rapid cuff deflation) would relate to lower extremity function, as assessed by jumping ability. College football athletes (linemen, defensive backs/wide receivers) were compared to sedentary healthy controls. BOLD signal of the gastrocnemius, soleus, anterior tibialis, and peroneus longus was assessed for peak hyperemic value (PHV), time to peak (TTP), minimum ischemic value (MIV), and time to recovery (TTR). Significantly higher PHVs were identified in athletes versus controls for the gastrocnemius (linemen, 15.8 ± 9.1%; defensive backs/wide receivers, 17.9 ± 5.1%; controls, 7.4 ± 3.5%), soleus (linemen, 25.9 ± 11.5%; backs/receivers, 22.0 ± 9.4%; controls, 12.9 ± 5.8%), and anterior tibialis (linemen, 12.8 ± 5.3%; backs/receivers, 12.6 ± 3.9%; controls, 7.7 ± 4.0%), whereas no differences in PHV were found for the peroneus longus (linemen, 14.1 ± 6.9%; backs/receivers, 11.7 ± 4.6%; controls, 9.0 ± 4.9%). In all subject groups, the gastrocnemius and soleus muscles exhibited the lowest MIVs during cuff occlusion. No differences in TTR were found between muscles for any subject group. PHV of the gastrocnemius muscle was significantly and positively related to maximal vertical (r = 0.56, P = 0.002) and broad jump (r = 0.47, P = 0.01). These results suggest that BOLD MR imaging is a useful noninvasive tool for evaluating differences in tissue oxygenation of specific muscles between active and sedentary individuals, and peak BOLD responses may relate to functional capacity. © 2016 The Authors. Physiological Reports published by Wiley

  14. Flexible cortical control of task-specific muscle synergies.

    Science.gov (United States)

    Nazarpour, Kianoush; Barnard, Amy; Jackson, Andrew

    2012-09-05

    Correlation structure in the activity of muscles across movements is often interpreted as evidence for low-level, hardwired constraints on upper-limb function. However, muscle synergies may also emerge from optimal strategies to achieve high-level task goals within a redundant control space. To distinguish these contrasting interpretations, we examined the structure of muscle variability during operation of a myoelectric interface in which task constraints were dissociated from natural limb biomechanics. We found that, with practice, human subjects learned to shape patterns of covariation between arbitrary pairs of hand and forearm muscles appropriately for elliptical targets whose orientation varied on a trial-by-trial basis. Thus, despite arriving at the same average location in the effector space, performance was improved by buffering variability into those dimensions that least impacted task success. Task modulation of beta-frequency intermuscular coherence indicated that differential recruitment of divergent corticospinal pathways contributed to positive correlations among muscles. However, this feedforward mechanism could not account for negative correlations observed in the presence of visual feedback. A second experiment revealed the development of fast, target-dependent visual responses consistent with "minimum intervention" control correcting predominantly task-relevant errors. Together, these mechanisms contribute to the dynamic emergence of task-specific muscle synergies appropriate for a wide range of abstract task goals.

  15. Stereovision and augmented reality for closed-loop control of grasping in hand prostheses

    Science.gov (United States)

    Markovic, Marko; Dosen, Strahinja; Cipriani, Christian; Popovic, Dejan; Farina, Dario

    2014-08-01

    Objective. Technologically advanced assistive devices are nowadays available to restore grasping, but effective and effortless control integrating both feed-forward (commands) and feedback (sensory information) is still missing. The goal of this work was to develop a user friendly interface for the semi-automatic and closed-loop control of grasping and to test its feasibility. Approach. We developed a controller based on stereovision to automatically select grasp type and size and augmented reality (AR) to provide artificial proprioceptive feedback. The system was experimentally tested in healthy subjects using a dexterous hand prosthesis to grasp a set of daily objects. The subjects wore AR glasses with an integrated stereo-camera pair, and triggered the system via a simple myoelectric interface. Main results. The results demonstrated that the subjects got easily acquainted with the semi-autonomous control. The stereovision grasp decoder successfully estimated the grasp type and size in realistic, cluttered environments. When allowed (forced) to correct the automatic system decisions, the subjects successfully utilized the AR feedback and achieved close to ideal system performance. Significance. The new method implements a high level, low effort control of complex functions in addition to the low level closed-loop control. The latter is achieved by providing rich visual feedback, which is integrated into the real life environment. The proposed system is an effective interface applicable with small alterations for many advanced prosthetic and orthotic/therapeutic rehabilitation devices.

  16. Stereovision and augmented reality for closed-loop control of grasping in hand prostheses.

    Science.gov (United States)

    Markovic, Marko; Dosen, Strahinja; Cipriani, Christian; Popovic, Dejan; Farina, Dario

    2014-08-01

    Technologically advanced assistive devices are nowadays available to restore grasping, but effective and effortless control integrating both feed-forward (commands) and feedback (sensory information) is still missing. The goal of this work was to develop a user friendly interface for the semi-automatic and closed-loop control of grasping and to test its feasibility. We developed a controller based on stereovision to automatically select grasp type and size and augmented reality (AR) to provide artificial proprioceptive feedback. The system was experimentally tested in healthy subjects using a dexterous hand prosthesis to grasp a set of daily objects. The subjects wore AR glasses with an integrated stereo-camera pair, and triggered the system via a simple myoelectric interface. The results demonstrated that the subjects got easily acquainted with the semi-autonomous control. The stereovision grasp decoder successfully estimated the grasp type and size in realistic, cluttered environments. When allowed (forced) to correct the automatic system decisions, the subjects successfully utilized the AR feedback and achieved close to ideal system performance. The new method implements a high level, low effort control of complex functions in addition to the low level closed-loop control. The latter is achieved by providing rich visual feedback, which is integrated into the real life environment. The proposed system is an effective interface applicable with small alterations for many advanced prosthetic and orthotic/therapeutic rehabilitation devices.

  17. Electromyography data for non-invasive naturally-controlled robotic hand prostheses.

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Castellini, Claudio; Caputo, Barbara; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Müller, Henning

    2014-01-01

    Recent advances in rehabilitation robotics suggest that it may be possible for hand-amputated subjects to recover at least a significant part of the lost hand functionality. The control of robotic prosthetic hands using non-invasive techniques is still a challenge in real life: myoelectric prostheses give limited control capabilities, the control is often unnatural and must be learned through long training times. Meanwhile, scientific literature results are promising but they are still far from fulfilling real-life needs. This work aims to close this gap by allowing worldwide research groups to develop and test movement recognition and force control algorithms on a benchmark scientific database. The database is targeted at studying the relationship between surface electromyography, hand kinematics and hand forces, with the final goal of developing non-invasive, naturally controlled, robotic hand prostheses. The validation section verifies that the data are similar to data acquired in real-life conditions, and that recognition of different hand tasks by applying state-of-the-art signal features and machine-learning algorithms is possible.

  18. Electromyography data for non-invasive naturally-controlled robotic hand prostheses

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Castellini, Claudio; Caputo, Barbara; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Müller, Henning

    2014-01-01

    Recent advances in rehabilitation robotics suggest that it may be possible for hand-amputated subjects to recover at least a significant part of the lost hand functionality. The control of robotic prosthetic hands using non-invasive techniques is still a challenge in real life: myoelectric prostheses give limited control capabilities, the control is often unnatural and must be learned through long training times. Meanwhile, scientific literature results are promising but they are still far from fulfilling real-life needs. This work aims to close this gap by allowing worldwide research groups to develop and test movement recognition and force control algorithms on a benchmark scientific database. The database is targeted at studying the relationship between surface electromyography, hand kinematics and hand forces, with the final goal of developing non-invasive, naturally controlled, robotic hand prostheses. The validation section verifies that the data are similar to data acquired in real-life conditions, and that recognition of different hand tasks by applying state-of-the-art signal features and machine-learning algorithms is possible. PMID:25977804

  19. Learning an EMG Controlled Game: Task-Specific Adaptations and Transfer.

    Science.gov (United States)

    van Dijk, Ludger; van der Sluis, Corry K; van Dijk, Hylke W; Bongers, Raoul M

    2016-01-01

    Video games that aim to improve myoelectric control (myogames) are gaining popularity and are often part of the rehabilitation process following an upper limb amputation. However, direct evidence for their effect on prosthetic skill is limited. This study aimed to determine whether and how myogaming improves EMG control and whether performance improvements transfer to a prosthesis-simulator task. Able-bodied right-handed participants (N = 28) were randomly assigned to 1 of 2 groups. The intervention group was trained to control a video game (Breakout-EMG) using the myosignals of wrist flexors and extensors. Controls played a regular Mario computer game. Both groups trained 20 minutes a day for 4 consecutive days. Before and after training, two tests were conducted: one level of the Breakout-EMG game, and grasping objects with a prosthesis-simulator. Results showed a larger increase of in-game accuracy for the Breakout-EMG group than for controls. The Breakout-EMG group moreover showed increased adaptation of the EMG signal to the game. No differences were found in using a prosthesis-simulator. This study demonstrated that myogames lead to task-specific myocontrol skills. Transfer to a prosthesis task is therefore far from easy. We discuss several implications for future myogame designs.

  20. Humans can integrate force feedback to toes in their sensorimotor control of a robotic hand.

    Science.gov (United States)

    Panarese, Alessandro; Edin, Benoni B; Vecchi, Fabrizio; Carrozza, Maria C; Johansson, Roland S

    2009-12-01

    Tactile sensory feedback is essential for dexterous object manipulation. Users of hand myoelectric prostheses without tactile feedback must depend essentially on vision to control their device. Indeed, improved tactile feedback is one of their main priorities. Previous research has provided evidence that conveying tactile feedback can improve prostheses control, although additional effort is required to solve problems related to pattern recognition learning, unpleasant sensations, sensory adaptation, and low spatiotemporal resolution. Still, these studies have mainly focused on providing stimulation to hairy skin regions close to the amputation site, i.e., usually to the upper arm. Here, we explored the possibility to provide tactile feedback to the glabrous skin of toes, which have mechanical and neurophysiological properties similar to the fingertips. We explored this paradigm in a grasp-and-lift task, in which healthy participants controlled two opposing digits of a robotic hand by changing the spacing of their index finger and thumb. The normal forces applied by the robotic fingertips to a test object were fed back to the right big and second toe. We show that within a few lifting trials, all the participants incorporated the force feedback received by the foot in their sensorimotor control of the robotic hand.

  1. Hand synergies: Integration of robotics and neuroscience for understanding the control of biological and artificial hands

    Science.gov (United States)

    Santello, Marco; Bianchi, Matteo; Gabiccini, Marco; Ricciardi, Emiliano; Salvietti, Gionata; Prattichizzo, Domenico; Ernst, Marc; Moscatelli, Alessandro; Jörntell, Henrik; Kappers, Astrid M. L.; Kyriakopoulos, Kostas; Albu-Schäffer, Alin; Castellini, Claudio; Bicchi, Antonio

    2016-07-01

    The term 'synergy' - from the Greek synergia - means 'working together'. The concept of multiple elements working together towards a common goal has been extensively used in neuroscience to develop theoretical frameworks, experimental approaches, and analytical techniques to understand neural control of movement, and for applications for neuro-rehabilitation. In the past decade, roboticists have successfully applied the framework of synergies to create novel design and control concepts for artificial hands, i.e., robotic hands and prostheses. At the same time, robotic research on the sensorimotor integration underlying the control and sensing of artificial hands has inspired new research approaches in neuroscience, and has provided useful instruments for novel experiments. The ambitious goal of integrating expertise and research approaches in robotics and neuroscience to study the properties and applications of the concept of synergies is generating a number of multidisciplinary cooperative projects, among which the recently finished 4-year European project ;The Hand Embodied; (THE). This paper reviews the main insights provided by this framework. Specifically, we provide an overview of neuroscientific bases of hand synergies and introduce how robotics has leveraged the insights from neuroscience for innovative design in hardware and controllers for biomedical engineering applications, including myoelectric hand prostheses, devices for haptics research, and wearable sensing of human hand kinematics. The review also emphasizes how this multidisciplinary collaboration has generated new ways to conceptualize a synergy-based approach for robotics, and provides guidelines and principles for analyzing human behavior and synthesizing artificial robotic systems based on a theory of synergies.

  2. Colgajo de avance en V-Y de gastrocnemio medial basado en perforante para cierre de defectos del tercio medio de la pierna V-Y advancement gastrocnemius perforant based flap for closure of defects of the medial third of the leg

    Directory of Open Access Journals (Sweden)

    V. Spröhnle

    2010-06-01

    Full Text Available Los colgajos de avance en V-Y han sido una alternativa popular para el cierre de heridas profundas, pero su movilidad es limitada. Los colgajos basados en perforantes son especialmente útiles cuando se necesita un mayor avance y cobertura. Diseñamos un colgajo de gastrocnemio que utiliza ambas técnicas para cubrir los defectos del tercio medio y superior de la pierna en sus caras lateral y posterolateral. Evaluamos en forma retrospectiva 5 pacientes con heridas en el tercio medio y superior de la pierna, tratados entre enero de 2005 y septiembre de 2007 en un solo centro y por un mismo cirujano. Todos fueron varones, con un promedio de edad de 48 años y la etiología fue traumática en todos los casos. El vaso perforante se evaluó preoperatoriamente por medio de doppler color en todos los casos. Valoramos telefónicamente la satisfacción del paciente en el postoperatorio tardío. En todos los casos, encontramos los vasos perforantes identificados en el preoperatorio; el tiempo operatorio promedio fue de 1.8 horas. No hubo complicaciones; la cobertura fue exitosa en todos los casos y los pacientes se mostraron satisfechos en la encuesta realizada. El tiempo medio de seguimiento postoperatorio fue de 19 meses. En conclusión, creemos que el colgajo de avance en V-Y de gastrocnemio basado en perforante se presenta como una alternativa segura para el cierre de defectos del tercio medial y superior de la pierna, en un sólo tiempo quirúrgico y con buenos resultados estéticos y funcionales a largo plazo.Advancement V-Y flaps have been a popular choice for closure of deep wounds but their mobility is limited. Perforant based flaps are specially useful when greater advancement and bigger coverage are needed. We designed a gastrocnemius based flap that uses both techniques for covering the defects of the medial third of the leg. We follow a retrospective evaluation of 5 patients that had their wounds in the medial and superior third of the leg

  3. Prediction of distal arm joint angles from EMG and shoulder orientation for prosthesis control.

    Science.gov (United States)

    Akhtar, Aadeel; Hargrove, Levi J; Bretl, Timothy

    2012-01-01

    Current state-of-the-art upper limb myoelectric prostheses are limited by only being able to control a single degree of freedom at a time. However, recent studies have separately shown that the joint angles corresponding to shoulder orientation and upper arm EMG can predict the joint angles corresponding to elbow flexion/extension and forearm pronation/ supination, which would allow for simultaneous control over both degrees of freedom. In this preliminary study, we show that the combination of both upper arm EMG and shoulder joint angles may predict the distal arm joint angles better than each set of inputs alone. Also, with the advent of surgical techniques like targeted muscle reinnervation, which allows a person with an amputation intuitive muscular control over his or her prosthetic, our results suggest that including a set of EMG electrodes around the forearm increases performance when compared to upper arm EMG and shoulder orientation. We used a Time-Delayed Adaptive Neural Network to predict distal arm joint angles. Our results show that our network's root mean square error (RMSE) decreases and coefficient of determination (R(2)) increases when combining both shoulder orientation and EMG as inputs.

  4. Effects of noxious stimulation and pain expectations on neuromuscular control of the spine in patients with chronic low back pain.

    Science.gov (United States)

    Henchoz, Yves; Tétreau, Charles; Abboud, Jacques; Piché, Mathieu; Descarreaux, Martin

    2013-10-01

    Alterations of the neuromuscular control of the lumbar spine have been reported in patients with chronic low back pain (LBP). During trunk flexion and extension tasks, the reduced myoelectric activity of the low back extensor musculature observed during full trunk flexion is typically absent in patients with chronic LBP. To determine whether pain expectations could modulate neuromuscular responses to experimental LBP to a higher extent in patients with chronic LBP compared with controls. A cross-sectional, case-control study. Twenty-two patients with nonspecific chronic LBP and 22 age- and sex-matched control participants. Trunk flexion-extension tasks were performed under three experimental conditions: innocuous heat, noxious stimulation with low pain expectation, and noxious stimulation with high pain expectation. Noxious stimulations were delivered using a contact heat thermode applied on the skin of the lumbar region (L4-L5), whereas low or high pain expectations were induced by verbal and visual instructions. Surface electromyography of erector spinae at L2-L3 and L4-L5, as well as lumbopelvic kinematic variables were collected during the tasks. Pain was evaluated using a numerical rating scale. Pain catastrophizing, disability, anxiety, and fear-avoidance beliefs were measured using validated questionnaires. Two-way mixed analysis of variance revealed that pain was significantly different among the three experimental conditions (F2,84=317.5; plow back extensor musculature during full trunk flexion was observed in the high compared with low pain expectations condition at the L2-L3 level (F2,84=9.5; ppain catastrophizing in patients with chronic LBP (r=0.54; p=.012). Repeated exposure to pain appears to generate rigid and less variable patterns of muscle activation in patients with chronic LBP, which attenuate their response to pain expectations. Patients with high levels of pain catastrophizing show higher myoelectric activity of lumbar muscles in full flexion

  5. Feasibility of using combined EMG and kinematic signals for prosthesis control: A simulation study using a virtual reality environment.

    Science.gov (United States)

    Blana, Dimitra; Kyriacou, Theocharis; Lambrecht, Joris M; Chadwick, Edward K

    2016-08-01

    Transhumeral amputation has a significant effect on a person's independence and quality of life. Myoelectric prostheses have the potential to restore upper limb function, however their use is currently limited due to lack of intuitive and natural control of multiple degrees of freedom. The goal of this study was to evaluate a novel transhumeral prosthesis controller that uses a combination of kinematic and electromyographic (EMG) signals recorded from the person's proximal humerus. Specifically, we trained a time-delayed artificial neural network to predict elbow flexion/extension and forearm pronation/supination from six proximal EMG signals, and humeral angular velocity and linear acceleration. We evaluated this scheme with ten able-bodied subjects offline, as well as in a target-reaching task presented in an immersive virtual reality environment. The offline training had a target of 4° for flexion/extension and 8° for pronation/supination, which it easily exceeded (2.7° and 5.5° respectively). During online testing, all subjects completed the target-reaching task with path efficiency of 78% and minimal overshoot (1.5%). Thus, combining kinematic and muscle activity signals from the proximal humerus can provide adequate prosthesis control, and testing in a virtual reality environment can provide meaningful data on controller performance. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. The immediate effect of triceps surae myofascial trigger point therapy on restricted active ankle joint dorsiflexion in recreational runners: a crossover randomised controlled trial.

    Science.gov (United States)

    Grieve, Rob; Cranston, Amy; Henderson, Andrew; John, Rachel; Malone, George; Mayall, Christopher

    2013-10-01

    To investigate the immediate effect on restricted active ankle joint dorsiflexion range of motion (ROM), after a single intervention of myofascial trigger point (MTrP) therapy on latent triceps surae MTrPs in recreational runners. A crossover randomised controlled trial. Twenty-two recreational runners (11 men and 11 women; mean age 24.57; ±8.7 years) with a restricted active ankle joint dorsiflexion and presence of latent MTrPs. Participants were screened for a restriction in active ankle dorsiflexion in either knee flexion (soleus) or knee extension (gastrocnemius) and the presence of latent MTrPs. Participants were randomly allocated a week apart to both the intervention (combined pressure release and 10 s passive stretch) and the control condition. A clinically meaningful (large effect size) and statistically significant increase in ankle ROM in the intervention compared to the control group was achieved, for the soleus (p = 0.004) and the gastrocnemius (p = 0.026). Apart from the statistical significance (p < 0.05), these results are clinically relevant due to the immediate increase in ankle dorsiflexion. These results must be viewed in caution due to the carry-over effect in the RCT crossover design and the combined MTrP therapy approach. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Musculoskeletal model-based control interface mimics physiologic hand dynamics during path tracing task

    Science.gov (United States)

    Crouch, Dustin L.; (Helen Huang, He

    2017-06-01

    Objective. We investigated the feasibility of a novel, customizable, simplified EMG-driven musculoskeletal model for estimating coordinated hand and wrist motions during a real-time path tracing task. Approach. A two-degree-of-freedom computational musculoskeletal model was implemented for real-time EMG-driven control of a stick figure hand displayed on a computer screen. After 5-10 minutes of undirected practice, subjects were given three attempts to trace 10 straight paths, one at a time, with the fingertip of the virtual hand. Able-bodied subjects completed the task on two separate test days. Main results. Across subjects and test days, there was a significant linear relationship between log-transformed measures of accuracy and speed (Pearson’s r  =  0.25, p  bodied subjects in 8 of 10 trials. For able-bodied subjects, tracing accuracy was lower at the extremes of the model’s range of motion, though there was no apparent relationship between tracing accuracy and fingertip location for the amputee. Our result suggests that, unlike able-bodied subjects, the amputee’s motor control patterns were not accustomed to the multi-joint dynamics of the wrist and hand, possibly as a result of post-amputation cortical plasticity, disuse, or sensory deficits. Significance. To our knowledge, our study is one of very few that have demonstrated the real-time simultaneous control of multi-joint movements, especially wrist and finger movements, using an EMG-driven musculoskeletal model, which differs from the many data-driven algorithms that dominate the literature on EMG-driven prosthesis control. Real-time control was achieved with very little training and simple, quick (~15 s) calibration. Thus, our model is potentially a practical and effective control platform for multifunctional myoelectric prostheses that could restore more life-like hand function for individuals with upper limb amputation.

  8. Biomechanical Reconstruction Using the Tacit Learning System: Intuitive Control of Prosthetic Hand Rotation.

    Science.gov (United States)

    Oyama, Shintaro; Shimoda, Shingo; Alnajjar, Fady S K; Iwatsuki, Katsuyuki; Hoshiyama, Minoru; Tanaka, Hirotaka; Hirata, Hitoshi

    2016-01-01

    Background: For mechanically reconstructing human biomechanical function, intuitive proportional control, and robustness to unexpected situations are required. Particularly, creating a functional hand prosthesis is a typical challenge in the reconstruction of lost biomechanical function. Nevertheless, currently available control algorithms are in the development phase. The most advanced algorithms for controlling multifunctional prosthesis are machine learning and pattern recognition of myoelectric signals. Despite the increase in computational speed, these methods cannot avoid the requirement of user consciousness and classified separation errors. "Tacit Learning System" is a simple but novel adaptive control strategy that can self-adapt its posture to environment changes. We introduced the strategy in the prosthesis rotation control to achieve compensatory reduction, as well as evaluated the system and its effects on the user. Methods: We conducted a non-randomized study involving eight prosthesis users to perform a bar relocation task with/without Tacit Learning System support. Hand piece and body motions were recorded continuously with goniometers, videos, and a motion-capture system. Findings: Reduction in the participants' upper extremity rotatory compensation motion was monitored during the relocation task in all participants. The estimated profile of total body energy consumption improved in five out of six participants. Interpretation: Our system rapidly accomplished nearly natural motion without unexpected errors. The Tacit Learning System not only adapts human motions but also enhances the human ability to adapt to the system quickly, while the system amplifies compensation generated by the residual limb. The concept can be extended to various situations for reconstructing lost functions that can be compensated.

  9. Primary Hydatid Cyst in Gastrocnemius Muscle | Bharati | Nigerian ...

    African Journals Online (AJOL)

    Cystic echinococcosis, which is caused by the larval stages of Echinococcus granulosus, results from the presence of one or more massive cysts or hydatids, and can involve any organ, including the liver, lungs, heart, brain, kidneys, and long bones. Muscle hydatidosis is usually secondary in nature, resulting from spread of ...

  10. Sensitivity and Specificity of Hypnosis Effects on Gastric Myoelectrical Activity

    Science.gov (United States)

    Enck, Paul; Weimer, Katja; Muth, Eric R.; Zipfel, Stephan; Martens, Ute

    2013-01-01

    Objectives The effects of hypnosis on physiological (gastrointestinal) functions are incompletely understood, and it is unknown whether they are hypnosis-specific and gut-specific, or simply unspecific effects of relaxation. Design Sixty-two healthy female volunteers were randomly assigned to either a single session of hypnotic suggestion of ingesting an appetizing meal and an unappetizing meal, or to relax and concentrate on having an appetizing or unappetizing meal, while the electrogastrogram (EGG) was recorded. At the end of the session, participants drank water until they felt full, in order to detect EGG-signal changes after ingestion of a true gastric load. During both conditions participants reported their subjective well-being, hunger and disgust at several time points. Results Imagining eating food induced subjective feelings of hunger and disgust as well as changes in the EGG similar to, but more pronounced than those seen with a real gastric water load during both hypnosis and relaxation conditions. These effects were more pronounced when imagining an appetizing meal than with an unappetizing meal. There was no significant difference between the hypnosis and relaxation conditions. Conclusion Imagination with and without hypnosis exhibits similar changes in subjective and objective measures in response to imagining an appetizing and an unappetizing food, indicating high sensitivity but low specificity. PMID:24358287

  11. Hand synergies: Integration of robotics and neuroscience for understanding the control of biological and artificial hands

    Science.gov (United States)

    Santello, Marco; Bianchi, Matteo; Gabiccini, Marco; Ricciardi, Emiliano; Salvietti, Gionata; Prattichizzo, Domenico; Ernst, Marc; Moscatelli, Alessandro; Jörntell, Henrik; Kappers, Astrid M.L.; Kyriakopoulos, Kostas; Albu-Schäffer, Alin; Castellini, Claudio; Bicchi, Antonio

    2017-01-01

    The term ‘synergy’ – from the Greek synergia – means ‘working together’. The concept of multiple elements working together towards a common goal has been extensively used in neuroscience to develop theoretical frameworks, experimental approaches, and analytical techniques to understand neural control of movement, and for applications for neuro-rehabilitation. In the past decade, roboticists have successfully applied the framework of synergies to create novel design and control concepts for artificial hands, i.e., robotic hands and prostheses. At the same time, robotic research on the sensorimotor integration underlying the control and sensing of artificial hands has inspired new research approaches in neuroscience, and has provided useful instruments for novel experiments. The ambitious goal of integrating expertise and research approaches in robotics and neuroscience to study the properties and applications of the concept of synergies is generating a number of multidisciplinary cooperative projects, among which the recently finished 4-year European project “The Hand Embodied” (THE). This paper reviews the main insights provided by this framework. Specifically, we provide an overview of neuroscientific bases of hand synergies and introduce how robotics has leveraged the insights from neuroscience for innovative design in hardware and controllers for biomedical engineering applications, including myoelectric hand prostheses, devices for haptics research, and wearable sensing of human hand kinematics. The review also emphasizes how this multidisciplinary collaboration has generated new ways to conceptualize a synergy-based approach for robotics, and provides guidelines and principles for analyzing human behavior and synthesizing artificial robotic systems based on a theory of synergies. PMID:26923030

  12. Hand synergies: Integration of robotics and neuroscience for understanding the control of biological and artificial hands.

    Science.gov (United States)

    Santello, Marco; Bianchi, Matteo; Gabiccini, Marco; Ricciardi, Emiliano; Salvietti, Gionata; Prattichizzo, Domenico; Ernst, Marc; Moscatelli, Alessandro; Jörntell, Henrik; Kappers, Astrid M L; Kyriakopoulos, Kostas; Albu-Schäffer, Alin; Castellini, Claudio; Bicchi, Antonio

    2016-07-01

    The term 'synergy' - from the Greek synergia - means 'working together'. The concept of multiple elements working together towards a common goal has been extensively used in neuroscience to develop theoretical frameworks, experimental approaches, and analytical techniques to understand neural control of movement, and for applications for neuro-rehabilitation. In the past decade, roboticists have successfully applied the framework of synergies to create novel design and control concepts for artificial hands, i.e., robotic hands and prostheses. At the same time, robotic research on the sensorimotor integration underlying the control and sensing of artificial hands has inspired new research approaches in neuroscience, and has provided useful instruments for novel experiments. The ambitious goal of integrating expertise and research approaches in robotics and neuroscience to study the properties and applications of the concept of synergies is generating a number of multidisciplinary cooperative projects, among which the recently finished 4-year European project "The Hand Embodied" (THE). This paper reviews the main insights provided by this framework. Specifically, we provide an overview of neuroscientific bases of hand synergies and introduce how robotics has leveraged the insights from neuroscience for innovative design in hardware and controllers for biomedical engineering applications, including myoelectric hand prostheses, devices for haptics research, and wearable sensing of human hand kinematics. The review also emphasizes how this multidisciplinary collaboration has generated new ways to conceptualize a synergy-based approach for robotics, and provides guidelines and principles for analyzing human behavior and synthesizing artificial robotic systems based on a theory of synergies. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. A series of case studies on the effect of a midfoot control ankle foot orthosis in the prevention of unresolved pressure areas in children with cerebral palsy.

    Science.gov (United States)

    Bill, M; McIntosh, R; Myers, P

    2001-12-01

    This paper reports on a series of case studies where improvements were sought in muscle tone and gait in children with cerebral palsy. A Midfoot Control Ankle Foot Orthosis (AFO) was developed to control foot position in a cohort of patients with cerebral palsy (CP). The concept of controlling midfoot and hindfoot with an encapsulated internal Supra-Malleolar AFO that fitted into an external AFO was shown to be effective in ambulant children with CP. Some initial problems of compliance were noted and postulated to be due to difficulties associated with previous orthotic devices. Evidence from the case studies suggest that the developed Supra-Malleolar AFO orthoses enables children with CP to maintain mobility without skin tissue damage, delays the need for surgery and at the same time maintains the length of the Triceps Surae (Gastrocnemius and Soleus) complex. Plans for further research are discussed which will contribute to the evidence base for this particular orthotic device.

  14. Evaluating EMG Feature and Classifier Selection for Application to Partial-Hand Prosthesis Control

    Directory of Open Access Journals (Sweden)

    Adenike A. Adewuyi

    2016-10-01

    Full Text Available Pattern recognition-based myoelectric control of upper limb prostheses has the potential to restore control of multiple degrees of freedom. Though this control method has been extensively studied in individuals with higher-level amputations, few studies have investigated its effectiveness for individuals with partial-hand amputations. Most partial-hand amputees retain a functional wrist and the ability of pattern recognition-based methods to correctly classify hand motions from different wrist positions is not well studied. In this study, focusing on partial-hand amputees, we evaluate (1 the performance of non-linear and linear pattern recognition algorithms and (2 the performance of optimal EMG feature subsets for classification of four hand motion classes in different wrist positions for 16 non-amputees and 4 amputees. Our results show that linear discriminant analysis and linear and non-linear artificial neural networks perform significantly better than the quadratic discriminant analysis for both non-amputees and partial-hand amputees. For amputees, including information from multiple wrist positions significantly decreased error (p<0.001 but no further significant decrease in error occurred when more than 4, 2, or 3 positions were included for the extrinsic (p=0.07, intrinsic (p=0.06, or combined extrinsic and intrinsic muscle EMG (p=0.08, respectively. Finally, we found that a feature set determined by selecting optimal features from each channel outperformed the commonly used time domain (p<0.001 and time domain/autoregressive feature sets (p<0.01. This method can be used as a screening filter to select the features from each channel that provide the best classification of hand postures across different wrist positions.

  15. Computer-controlled pneumatic pressure algometry--a new technique for quantitative sensory testing.

    Science.gov (United States)

    Polianskis, R; Graven-Nielsen, T; Arendt-Nielsen, L

    2001-01-01

    Hand-held pressure algometry usually assesses pressure-pain detection thresholds and provides little information on pressure-pain stimulus-response function. In this article, a cuff pressure algometry for advanced pressure-pain function evaluation is proposed. The experimental set-up consisted of a pneumatic tourniquet cuff, a computer-controlled air compressor and an electronic visual analogue scale (VAS) for constant pain intensity rating. Twelve healthy volunteers were included in the study. In the first part, hand-held algometry and cuff algometry were performed over the gastrocnemius muscle with constant compression rate. In the second part, the cuff algometry was performed with different compression rates to evaluate the influence of the compression rate on pain thresholds and other psychophysical data. Pressure-pain detection threshold (PDT), pain tolerance threshold (PTT), pain intensity, PDT-PTT time and other psychophysical variables were evaluated.Pressure-pain detection thresholds recorded over the gastrocnemius muscle with a hand-held and with a cuff algometer, were 482 +/- 19 kPa and 26 +/- 1.6 kPa, respectively. Pressure and pain intensities were correlated during cuff algometry. During increasing cuff compression, the subjective pain tolerance limit on VAS was 5.6 +/- 0.95 cm. There was a direct correlation between the number of compressions, the compression rate and pain thresholds. The cuff algometry technique is appropriate for pressure-pain stimulus-response studies. Cuff algometry allowed quantification of psychophysical response to the change of stimulus configuration. Copyright 2001 European Federation of Chapters of the International Association for the Study of Pain.

  16. Template model inspired leg force feedback based control can assist human walking.

    Science.gov (United States)

    Zhao, Guoping; Sharbafi, Maziar; Vlutters, Mark; van Asseldonk, Edwin; Seyfarth, Andre

    2017-07-01

    We present a novel control approach for assistive lower-extremity exoskeletons. In particular, we implement a virtual pivot point (VPP) template model inspired leg force feedback based controller on a lower-extremity powered exoskeleton (LOPES II) and demonstrate that it can effectively assist humans during walking. It has been shown that the VPP template model is capable of stabilizing the trunk and reproduce a human-like hip torque during the stance phase of walking. With leg force and joint angle feedback inspired by the VPP template model, our controller provides hip and knee torque assistance during the stance phase. A pilot experiment was conducted with four healthy subjects. Joint kinematics, leg muscle electromyography (EMG), and metabolic cost were measured during walking with and without assistance. Results show that, for 0.6 m/s walking, our controller can reduce leg muscle activations, especially for the medial gastrocnemius (about 16.0%), while hip and knee joint kinematics remain similar to the condition without the controller. Besides, the controller also reduces 10% of the net metabolic cost during walking. This paper demonstrates walking assistance benefits of the VPP template model for the first time. The support of human walking is achieved by a force feedback of leg force applied to the control of hip and knee joints. It can help us to provide a framework for investigating walking assistance control in the future.

  17. Altered knee joint neuromuscular control during landing from a jump in 10-15 year old children with generalised joint hypermobility. A substudy of the CHAMPS-study Denmark

    DEFF Research Database (Denmark)

    Junge, Tina; Juul-Kristensen, B; Bloch Thorlund, Jonas

    Generalised Joint Hypermobility (GJH) is considered an intrinsic risk factor for knee injuries. Knee neuromuscular control during landing may be altered in GJH due to reduced passive stability. The aim was to identify differences in knee neuromuscular control during landing of the Single......-Leg-Hop-for-Distance test (SLHD) in 25 children with GJH compared to 29 children without GJH (controls), all 10-15 years. Inclusion criteria for GJH: Beighton score ≥5/9 and minimum one hypermobile knee. EMG was recorded from the quadriceps, the hamstring and the calf muscles, presented relative to Maximum Voluntary...... Electrical activity (MVE). There was no difference in jump length between groups. Before landing, GJH had 33% lower Semitendinosus, but 32% higher Gastrocnemius Medialis activity and 39% higher co-contraction of the lateral knee muscles, than controls. After landing, GJH had 36% lower Semitendinosus activity...

  18. Altered knee joint neuromuscular control during landing from a jump in 10-15year old children with Generalised Joint Hypermobility. A substudy of the CHAMPS-study Denmark

    DEFF Research Database (Denmark)

    Junge, Tina; Wedderkopp, Niels; Thorlund, Jonas Bloch

    2015-01-01

    Generalised Joint Hypermobility (GJH) is considered an intrinsic risk factor for knee injuries. Knee neuromuscular control during landing may be altered in GJH due to reduced passive stability. The aim was to identify differences in knee neuromuscular control during landing of the Single......-Leg-Hop-for-Distance test (SLHD) in 25 children with GJH compared to 29 children without GJH (controls), all 10-15years. Inclusion criteria for GJH: Beighton score⩾5/9 and minimum one hypermobile knee. EMG was recorded from the quadriceps, the hamstring and the calf muscles, presented relative to Maximum Voluntary...... Electrical activity (MVE). There was no difference in jump length between groups. Before landing, GJH had 33% lower Semitendinosus, but 32% higher Gastrocnemius Medialis activity and 39% higher co contraction of the lateral knee muscles, than controls. After landing, GJH had 36% lower Semitendinosus activity...

  19. Does giving segmental muscle vibration alter the response to botulinum toxin injections in the treatment of spasticity in people with multiple sclerosis? A single-blind randomized controlled trial.

    Science.gov (United States)

    Paoloni, Marco; Giovannelli, Morena; Mangone, Massimiliano; Leonardi, Laura; Tavernese, Emanuela; Di Pangrazio, Elisabetta; Bernetti, Andrea; Santilli, Valter; Pozzilli, Carlo

    2013-09-01

    To determine if segmental muscle vibration and botulinum toxin-A injection, either alone or in combination, reduces spasticity in a sample of patients with multiple sclerosis. Single-blind, randomized controlled trial. Physical medicine and rehabilitation outpatients service. Forty-two patients affected by the secondary progressive form of multiple sclerosis randomized to group A (30 minutes of 120 Hz segmental muscle vibration over the rectus femoris and gastrocnemius medial and lateral, three per week, over a period of four weeks), group B (botulinum toxin in the rectus femoris, gastrocnemius medial and lateral and soleus, and segmental muscle vibration) and group C (botulinum toxin). Modified Ashworth Scale at knee and ankle, and Fatigue Severity Scale. All the measurements were performed at baseline (T0), 10 weeks (T1) and 22 weeks (T2) postallocation. Modified Ashworth Scale at knee and ankle significantly decreased over time (p spasticity at T2 when compared with T1 (p spasticity and improves fatigue in the medium-term follow-up in patients with multiple sclerosis.

  20. Real-time muscle state estimation from EMG signals during isometric contractions using Kalman filters.

    Science.gov (United States)

    Menegaldo, Luciano L

    2017-12-01

    State-space control of myoelectric devices and real-time visualization of muscle forces in virtual rehabilitation require measuring or estimating muscle dynamic states: neuromuscular activation, tendon force and muscle length. This paper investigates whether regular (KF) and extended Kalman filters (eKF), derived directly from Hill-type muscle mechanics equations, can be used as real-time muscle state estimators for isometric contractions using raw electromyography signals (EMG) as the only available measurement. The estimators' amplitude error, computational cost, filtering lags and smoothness are compared with usual EMG-driven analysis, performed offline, by integrating the nonlinear Hill-type muscle model differential equations (offline simulations-OS). EMG activity of the three triceps surae components (soleus, gastrocnemius medialis and gastrocnemius lateralis), in three torque levels, was collected for ten subjects. The actualization interval (AI) between two updates of the KF and eKF was also varied. The results show that computational costs are significantly reduced (70x for KF and 17[Formula: see text] for eKF). The filtering lags presented sharp linear relationships with the AI (0-300 ms), depending on the state and activation level. Under maximum excitation, amplitude errors varied in the range 10-24% for activation, 5-8% for tendon force and 1.4-1.8% for muscle length, reducing linearly with the excitation level. Smoothness, measured by the ratio between the average standard variations of KF/eKF and OS estimations, was greatly reduced for activation but converged exponentially to 1 for the other states by increasing AI. Compared to regular KF, extended KF does not seem to improve estimation accuracy significantly. Depending on the particular application requirements, the most appropriate KF actualization interval can be selected.

  1. Muscle-tendon units localization and activation level analysis based on high-density surface EMG array and NMF algorithm

    Science.gov (United States)

    Huang, Chengjun; Chen, Xiang; Cao, Shuai; Zhang, Xu

    2016-12-01

    Objective. Some skeletal muscles can be subdivided into smaller segments called muscle-tendon units (MTUs). The purpose of this paper is to propose a framework to locate the active region of the corresponding MTUs within a single skeletal muscle and to analyze the activation level varieties of different MTUs during a dynamic motion task. Approach. Biceps brachii and gastrocnemius were selected as targeted muscles and three dynamic motion tasks were designed and studied. Eight healthy male subjects participated in the data collection experiments, and 128-channel surface electromyographic (sEMG) signals were collected with a high-density sEMG electrode grid (a grid consists of 8 rows and 16 columns). Then the sEMG envelopes matrix was factorized into a matrix of weighting vectors and a matrix of time-varying coefficients by nonnegative matrix factorization algorithm. Main results. The experimental results demonstrated that the weightings vectors, which represent invariant pattern of muscle activity across all channels, could be used to estimate the location of MTUs and the time-varying coefficients could be used to depict the variation of MTUs activation level during dynamic motion task. Significance. The proposed method provides one way to analyze in-depth the functional state of MTUs during dynamic tasks and thus can be employed on multiple noteworthy sEMG-based applications such as muscle force estimation, muscle fatigue research and the control of myoelectric prostheses. This work was supported by the National Nature Science Foundation of China under Grant 61431017 and 61271138.

  2. Effects of wearing lower leg compression sleeves on locomotion economy.

    Science.gov (United States)

    Kurz, Eduard; Anders, Christoph

    2018-02-15

    The purpose of this investigation was to assess the effect of compression sleeves on muscle activation cost during locomotion. Twenty-two recreationally active men (age: 25 ± 3 years) ran on a treadmill at four different speeds (ordered sequence of 2.8, 3.3, 2.2, and 3.9 m/s). The tests were performed without (control situation, CON) and while wearing specially designed lower leg compression sleeves (SL). Myoelectric activity of five lower leg muscles (tibialis anterior, fibularis longus, lateral and medial head of gastrocnemius, and soleus) was captured using Surface EMG. To assess muscle activation cost, the cumulative muscle activity per distance travelled (CMAPD) of the CON and SL situations was determined. Repeated measures analyses of variance were performed separately for each muscle. The analyses revealed a reduced lower leg muscle activation cost with respect to test situation for SL for all muscles (p  0.18). The respective significant reductions of CMAPD values during SL ranged between 4% and 16% and were largest at 2.8 m/s. The findings presented point towards an improved muscle activation cost while wearing lower leg compression sleeves during locomotion that have potential to postpone muscle fatigue.

  3. Evaluation of lower limb electromyographic activity when using unstable shoes for the first time: a pilot quasi control trial.

    Science.gov (United States)

    Branthwaite, Helen; Chockalingam, Nachiappan; Pandyan, Anand; Khatri, Gaurav

    2013-08-01

    Unstable shoes, which have recently become popular, claim to provide additional physiological and biomechanical advantages to people who wear them. Alterations in postural stability have been shown when using the shoe after training. However, the immediate effect on muscle activity when walking in unstable shoes for the first time has not been investigated. To evaluate muscle activity and temporal parameters of gait when wearing Masai Barefoot Technology shoes(®) for the first time compared to the subject's own regular trainer shoes. A pilot repeated-measures quasi control trial. Electromyographic measurements of lower leg muscles (soleus, medial gastrocnemius, lateral gastrocnemius, tibialis anterior, peroneus longus, rectus femoris, biceps femoris and gluteus medius) were measured in 15 healthy participants using Masai Barefoot Technology shoes and trainer shoes over a 10-m walkway. Muscle activity of the third and sixth steps was used to study the difference in behaviour of the muscles under the two shoe conditions. Temporal parameters were captured with footswitches to highlight heel strike, heel lift and toe off. Paired samples t-test was completed to compare mean muscle activity for Masai Barefoot Technology and trainer shoes. Indicated that the use of Masai Barefoot Technology shoes increased the intensity of the magnitude of muscle activity. While this increase in the activity was not significant across the subjects, there were inter-individual differences in muscle activity. This variance between the participants demonstrates that some subjects do alter muscle behaviour while wearing such shoes. A more rigorous and specific assessment is required when advising patients to purchase the Masai Barefoot Technology shoe. Not all subjects respond positively to using unstable shoes, and the point in time when muscle behaviour can change is variable. Use of Masai Barefoot Technology shoe in patient management should be monitored closely as the individual muscle

  4. Locomotor adaptation to a soleus EMG-controlled antagonistic exoskeleton

    Science.gov (United States)

    Kinnaird, Catherine R.; Ferris, Daniel P.

    2013-01-01

    Locomotor adaptation in humans is not well understood. To provide insight into the neural reorganization that occurs following a significant disruption to one's learned neuromuscular map relating a given motor command to its resulting muscular action, we tied the mechanical action of a robotic exoskeleton to the electromyography (EMG) profile of the soleus muscle during walking. The powered exoskeleton produced an ankle dorsiflexion torque proportional to soleus muscle recruitment thus limiting the soleus' plantar flexion torque capability. We hypothesized that neurologically intact subjects would alter muscle activation patterns in response to the antagonistic exoskeleton by decreasing soleus recruitment. Subjects practiced walking with the exoskeleton for two 30-min sessions. The initial response to the perturbation was to “fight” the resistive exoskeleton by increasing soleus activation. By the end of training, subjects had significantly reduced soleus recruitment resulting in a gait pattern with almost no ankle push-off. In addition, there was a trend for subjects to reduce gastrocnemius recruitment in proportion to the soleus even though only the soleus EMG was used to control the exoskeleton. The results from this study demonstrate the ability of the nervous system to recalibrate locomotor output in response to substantial changes in the mechanical output of the soleus muscle and associated sensory feedback. This study provides further evidence that the human locomotor system of intact individuals is highly flexible and able to adapt to achieve effective locomotion in response to a broad range of neuromuscular perturbations. PMID:23307949

  5. Multisession, noninvasive closed-loop neuroprosthetic control of grasping by upper limb amputees.

    Science.gov (United States)

    Agashe, H A; Paek, A Y; Contreras-Vidal, J L

    2016-01-01

    Upper limb amputation results in a severe reduction in the quality of life of affected individuals due to their inability to easily perform activities of daily living. Brain-machine interfaces (BMIs) that translate grasping intent from the brain's neural activity into prosthetic control may increase the level of natural control currently available in myoelectric prostheses. Current BMI techniques demonstrate accurate arm position and single degree-of-freedom grasp control but are invasive and require daily recalibration. In this study we tested if transradial amputees (A1 and A2) could control grasp preshaping in a prosthetic device using a noninvasive electroencephalography (EEG)-based closed-loop BMI system. Participants attempted to grasp presented objects by controlling two grasping synergies, in 12 sessions performed over 5 weeks. Prior to closed-loop control, the first six sessions included a decoder calibration phase using action observation by the participants; thereafter, the decoder was fixed to examine neuroprosthetic performance in the absence of decoder recalibration. Ability of participants to control the prosthetic was measured by the success rate of grasping; ie, the percentage of trials within a session in which presented objects were successfully grasped. Participant A1 maintained a steady success rate (63±3%) across sessions (significantly above chance [41±5%] for 11 sessions). Participant A2, who was under the influence of pharmacological treatment for depression, hormone imbalance, pain management (for phantom pain as well as shoulder joint inflammation), and drug dependence, achieved a success rate of 32±2% across sessions (significantly above chance [27±5%] in only two sessions). EEG signal quality was stable across sessions, but the decoders created during the first six sessions showed variation, indicating EEG features relevant to decoding at a smaller timescale (100ms) may not be stable. Overall, our results show that (a) an EEG

  6. Noninvasive Reactivation of Motor Descending Control after Paralysis.

    Science.gov (United States)

    Gerasimenko, Yury P; Lu, Daniel C; Modaber, Morteza; Zdunowski, Sharon; Gad, Parag; Sayenko, Dimitry G; Morikawa, Erika; Haakana, Piia; Ferguson, Adam R; Roy, Roland R; Edgerton, V Reggie

    2015-12-15

    The present prognosis for the recovery of voluntary control of movement in patients diagnosed as motor complete is generally poor. Herein we introduce a novel and noninvasive stimulation strategy of painless transcutaneous electrical enabling motor control and a pharmacological enabling motor control strategy to neuromodulate the physiological state of the spinal cord. This neuromodulation enabled the spinal locomotor networks of individuals with motor complete paralysis for 2-6 years American Spinal Cord Injury Association Impairment Scale (AIS) to be re-engaged and trained. We showed that locomotor-like stepping could be induced without voluntary effort within a single test session using electrical stimulation and training. We also observed significant facilitation of voluntary influence on the stepping movements in the presence of stimulation over a 4-week period in each subject. Using these strategies we transformed brain-spinal neuronal networks from a dormant to a functional state sufficiently to enable recovery of voluntary movement in five out of five subjects. Pharmacological intervention combined with stimulation and training resulted in further improvement in voluntary motor control of stepping-like movements in all subjects. We also observed on-command selective activation of the gastrocnemius and soleus muscles when attempting to plantarflex. At the end of 18 weeks of weekly interventions the mean changes in the amplitude of voluntarily controlled movement without stimulation was as high as occurred when combined with electrical stimulation. Additionally, spinally evoked motor potentials were readily modulated in the presence of voluntary effort, providing electrophysiological evidence of the re-establishment of functional connectivity among neural networks between the brain and the spinal cord.

  7. Neuromuscular Control Mechanisms During Single-Leg Jump Landing in Subacute Ankle Sprain Patients: A Case Control Study.

    Science.gov (United States)

    Allet, Lara; Zumstein, Franziska; Eichelberger, Patric; Armand, Stéphane; Punt, Ilona M

    2017-03-01

    Optimal neuromuscular control mechanisms are essential for preparing, maintaining, and restoring functional joint stability during jump landing and to prevent ankle injuries. In subacute ankle sprain patients, neither muscle activity nor kinematics during jump landing has previously been assessed. To compare neuromuscular control mechanisms and kinematics between subacute ankle sprain patients and healthy persons before and during the initial contact phase of a 25-cm single-leg jump. Case-control study. University hospital. Fifteen patients with grade I or II acute ankle sprains were followed up after 4 weeks of conservative management not involving physical therapy. Subjects performed alternately 3 single-leg forward jumps of 25 cm (toe-to-heel distance) barefoot. Their results were compared with the data of 15 healthy subjects. Electromyographic (EMG) activity of the musculus (m.) gastrocnemius lateralis, m. tibialis anterior, and m. peroneus longus as well as kinematics for ankle, knee, and hip joint were recorded for pre-initial contact (IC) phase, post-initial contact phase, and reflex-induced phase. The results showed that EMG activity of the 3 muscles did not differ between ankle sprain patients (n = 15) and healthy persons (n = 15) for any of the analyzed time intervals (all P > .05). However, during the pre-IC phase, ankle sprain patients presented less plantar flexion, as well as during the post-IC phase after jump landing, compared to healthy persons (P ankle joint can lead to neuromuscular control mechanism disturbances through which functional instability might arise. III. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  8. How does practise of internal Chinese martial arts influence postural reaction control?

    Science.gov (United States)

    Gorgy, Olivier; Vercher, Jean-Louis; Coyle, Thelma

    2008-04-01

    The aim of this study was to determine the effects of Chinese martial arts practice on postural reaction control after perturbation. Participants standing in Romberg tandem posture were subjected to an unexpected lateral platform translation with the eyes open or closed at two translation amplitudes. The peak displacement of the centre of pressure and of the centre of mass, and the onset latency of muscular activity (tibialis anterior, gastrocnemius, lumbodorsal muscular group, and rectus abdominis), were evaluated for martial arts practitioners and for sport and non-sport participants. Compared with the sport and non-sport participants, the martial arts group showed lower maximal centre of pressure and centre of mass peak displacements in both the lateral and anterior - posterior directions, but no difference was found in the onset of muscular responses. We conclude that martial arts practice influences postural reaction control during a fixed-support strategy in a tandem task. The martial arts group used the ankle joint more frequently than the sport and non-sport participants, especially in the eyes-closed conditions. Our results suggest that the better balance recovery in the martial arts group is a consequence of better control of biomechanical properties of the lower limbs (e.g. through muscular response by co-contraction), not a change in the neuromuscular temporal pattern.

  9. Immediate therapeutic effect of interferential current therapy on spasticity, balance, and gait function in chronic stroke patients: a randomized control trial.

    Science.gov (United States)

    Suh, Hye Rim; Han, Hee Chul; Cho, Hwi-Young

    2014-09-01

    To determine whether a single trial of interferential current therapy (ICT) can immediately alleviate spasticity and improve balance and gait performance in patients with chronic stroke. Randomized, placebo-controlled clinical trial. Inpatient rehabilitation in a local center. A total of 42 adult patients with chronic stroke with plantar flexor spasticity of the lower limb. The ICT group received a single 60-minute ICT stimulation of the gastrocnemius in conjunction with air-pump massage. In the placebo-ICT group, electrodes were placed and air-pump massage performed without electrical stimulation. After a single ICT application, spasticity was measured immediately using the Modified Ashworth Scale (MAS), and balance and functional gait performance were assessed using the following clinical tools: Functional Reach Test (FRT), Berg Balance Scale (BBS), Timed Up and Go Test (TUG), and 10-m Walk Test (10MWT). Gastrocnemius spasticity significantly decreased in the ICT group than in the placebo-ICT group (MAS: ICT vs placebo-ICT: 1.55±0.76 vs 0.40±0.50). The ICT group showed significantly greater improvement in balance and gait abilities than the placebo-ICT group (FRT: 2.62±1.21 vs 0.61±1.34, BBS: 1.75±1.52 vs 0.40±0.88, TUG: 6.07±6.11 vs 1.68±2.39, 10MWT: 7.02±7.02 vs 1.96±3.13). Spasticity correlated significantly with balance and gait abilities (P < 0.05). A single trial of ICT is a useful intervention for immediately improving spasticity, balance, and gait abilities in chronic stroke patients, but not for long-term effects. Further study on the effects of repeated ICT is needed. © The Author(s) 2014.

  10. Control rod control device

    International Nuclear Information System (INIS)

    Seiji, Takehiko; Obara, Kohei; Yanagihashi, Kazumi

    1998-01-01

    The present invention provides a device suitable for switching of electric motors for driving each of control rods in a nuclear reactor. Namely, in a control rod controlling device, a plurality of previously allotted electric motors connected in parallel as groups, and electric motors of any selected group are driven. In this case, a voltage of not driving predetermined selected electric motors is at first applied. In this state an electric current supplied to the circuit of predetermined electric motors is detected. Whether integration or failure of a power source and the circuit of the predetermined electric motors are normal or not is judged by the detected electric current supplied. After they are judged normal, the electric motors are driven by a regular voltage. With such procedures, whether the selected circuit is normal or not can be accurately confirmed previously. Since the electric motors are not driven just at the selected time, the control rods are not operated erroneously. (I.S.)

  11. A Neuro-Fuzzy System for Characterization of Arm Movements

    Science.gov (United States)

    Balbinot, Alexandre; Favieiro, Gabriela

    2013-01-01

    The myoelectric signal reflects the electrical activity of skeletal muscles and contains information about the structure and function of the muscles which make different parts of the body move. Advances in engineering have extended electromyography beyond the traditional diagnostic applications to also include applications in diverse areas such as rehabilitation, movement analysis and myoelectric control of prosthesis. This paper aims to study and develop a system that uses myoelectric signals, acquired by surface electrodes, to characterize certain movements of the human arm. To recognize certain hand-arm segment movements, was developed an algorithm for pattern recognition technique based on neuro-fuzzy, representing the core of this research. This algorithm has as input the preprocessed myoelectric signal, to disclosed specific characteristics of the signal, and as output the performed movement. The average accuracy obtained was 86% to 7 distinct movements in tests of long duration (about three hours). PMID:23429579

  12. A Neuro-Fuzzy System for Characterization of Arm Movements

    Directory of Open Access Journals (Sweden)

    Alexandre Balbinot

    2013-02-01

    Full Text Available The myoelectric signal reflects the electrical activity of skeletal muscles and contains information about the structure and function of the muscles which make different parts of the body move. Advances in engineering have extended electromyography beyond the traditional diagnostic applications to also include applications in diverse areas such as rehabilitation, movement analysis and myoelectric control of prosthesis. This paper aims to study and develop a system that uses myoelectric signals, acquired by surface electrodes, to characterize certain movements of the human arm. To recognize certain hand-arm segment movements, was developed an algorithm for pattern recognition technique based on neuro-fuzzy, representing the core of this research. This algorithm has as input the preprocessed myoelectric signal, to disclosed specific characteristics of the signal, and as output the performed movement. The average accuracy obtained was 86% to 7 distinct movements in tests of long duration (about three hours.

  13. Perancangan Controller

    OpenAIRE

    Santoso, Djunaidi

    2010-01-01

    In making controller, there must be knowledge about component controlling functions that used for controller designing. In the control unit, it needs simple method as micro programming. This micro programming is to create a micro program in binary numbering that used for controlling pin’s component controller and outside the controller. Controller design in general needs several prerequisites, which are digital system and controller and assembly language. 

  14. Controllable dose; Dosis controlable

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T.; Anaya M, R.A. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)]. E-mail: jtar@nuclear.inin.mx

    2004-07-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  15. Dream controller

    Science.gov (United States)

    Cheng, George Shu-Xing; Mulkey, Steven L; Wang, Qiang; Chow, Andrew J

    2013-11-26

    A method and apparatus for intelligently controlling continuous process variables. A Dream Controller comprises an Intelligent Engine mechanism and a number of Model-Free Adaptive (MFA) controllers, each of which is suitable to control a process with specific behaviors. The Intelligent Engine can automatically select the appropriate MFA controller and its parameters so that the Dream Controller can be easily used by people with limited control experience and those who do not have the time to commission, tune, and maintain automatic controllers.

  16. Muscle Recruitment and Coordination following Constraint-Induced Movement Therapy with Electrical Stimulation on Children with Hemiplegic Cerebral Palsy: A Randomized Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Kaishou Xu

    Full Text Available To investigate changes of muscle recruitment and coordination following constraint-induced movement therapy, constraint-induced movement therapy plus electrical stimulation, and traditional occupational therapy in treating hand dysfunction.In a randomized, single-blind, controlled trial, children with hemiplegic cerebral palsy were randomly assigned to receive constraint-induced movement therapy (n = 22, constraint-induced movement therapy plus electrical stimulation (n = 23, or traditional occupational therapy (n = 23. Three groups received a 2-week hospital-based intervention and a 6-month home-based exercise program following hospital-based intervention. Constraint-induced movement therapy involved intensive functional training of the involved hand during which the uninvolved hand was constrained. Electrical stimulation was applied on wrist extensors of the involved hand. Traditional occupational therapy involved functional unimanual and bimanual training. All children underwent clinical assessments and surface electromyography (EMG at baseline, 2 weeks, 3 and 6 months after treatment. Surface myoelectric signals were integrated EMG, root mean square and cocontraction ratio. Clinical measures were grip strength and upper extremity functional test.Constraint-induced movement therapy plus electrical stimulation group showed both a greater rate of improvement in integrated EMG of the involved wrist extensors and cocontraction ratio compared to the other two groups at 3 and 6 months, as well as improving in root mean square of the involved wrist extensors than traditional occupational therapy group (p<0.05. Positive correlations were found between both upper extremity functional test scores and integrated EMG of the involved wrist as well as grip strength and integrated EMG of the involved wrist extensors (p<0.05.Constraint-induced movement therapy plus electrical stimulation is likely to produce the best outcome in improving muscle recruitment

  17. The effect of Functional Electric Stimulation in stroke patients' motor control - a case report

    International Nuclear Information System (INIS)

    Pripas, Denise; Rogers Venditi Beas, Allan; Fioramonte, Caroline; Gonsales de Castro, Pedro Claudio; Goroso, Daniel Gustavo; Santos Moreira, Maria Cecília dos

    2011-01-01

    Functional Electric Stimulation (FES) has been studied as a therapeutic resource to reduce spasticity in hemiplegic patients, however there are no studies about the effects of FES in motor control of these patients during functional tasks like balance maintenance. Muscular activation of gastrocnemius medialis and semitendinosus was investigated in both limbs of a hemiparetic patient during self-disturbed quiet stance before and after FES on tibialis anterior, by surface electromyography. The instant of maximum activation peak of GM and ST were calculated immediately after a motor self-disturbance, in order to observe muscular synergy between these two muscles, and possible balance strategies used (ankle or hip strategy). At the preserved limb there occurred distal-proximal synergy (GM followed by ST), expected for small perturbations; however, at spastic limb there was inversion of this synergy (proximal-distal) after FES. It is possible that intervention of electricity had inhibited synergical pathways due to antidromic effect, making it difficult to use ankle strategy in the spastic limb.

  18. Mosquito Control

    Science.gov (United States)

    ... Protection Agency Search Search Contact Us Share Mosquito Control About Mosquitoes General Information Life Cycle Information from ... Repellent that is Right for You DEET Mosquito Control Methods Success in mosquito control: an integrated approach ...

  19. Adaptive Admittance Control for an Ankle Exoskeleton Using an EMG-Driven Musculoskeletal Model

    Directory of Open Access Journals (Sweden)

    Shaowei Yao

    2018-04-01

    Full Text Available Various rehabilitation robots have been employed to recover the motor function of stroke patients. To improve the effect of rehabilitation, robots should promote patient participation and provide compliant assistance. This paper proposes an adaptive admittance control scheme (AACS consisting of an admittance filter, inner position controller, and electromyography (EMG-driven musculoskeletal model (EDMM. The admittance filter generates the subject's intended motion according to the joint torque estimated by the EDMM. The inner position controller tracks the intended motion, and its parameters are adjusted according to the estimated joint stiffness. Eight healthy subjects were instructed to wear the ankle exoskeleton robot, and they completed a series of sinusoidal tracking tasks involving ankle dorsiflexion and plantarflexion. The robot was controlled by the AACS and a non-adaptive admittance control scheme (NAACS at four fixed parameter levels. The tracking performance was evaluated using the jerk value, position error, interaction torque, and EMG levels of the tibialis anterior (TA and gastrocnemius (GAS. For the NAACS, the jerk value and position error increased with the parameter levels, and the interaction torque and EMG levels of the TA tended to decrease. In contrast, the AACS could maintain a moderate jerk value, position error, interaction torque, and TA EMG level. These results demonstrate that the AACS achieves a good tradeoff between accurate tracking and compliant assistance because it can produce a real-time response to stiffness changes in the ankle joint. The AACS can alleviate the conflict between accurate tracking and compliant assistance and has potential for application in robot-assisted rehabilitation.

  20. The influence of mechanical vibration on local and central balance control.

    Science.gov (United States)

    Ehsani, Hossein; Mohler, Jane; Marlinski, Vladimir; Rashedi, Ehsan; Toosizadeh, Nima

    2018-04-11

    Fall prevention has an indispensable role in enhancing life expectancy and quality of life among older adults. The first step to prevent falls is to devise reliable methods to identify individuals at high fall risk. The purpose of the current study was to assess alterations in local postural muscle and central sensory balance control mechanisms due to low-frequency externally applied vibration among elders at high fall risk, in comparison with healthy controls, as a potential tool for assessing fall risk. Three groups of participants were recruited: healthy young (n = 10; age = 23 ± 2 years), healthy elders (n = 10; age = 73 ± 3 years), and elders at high fall risk (n = 10; age = 84 ± 9 years). Eyes-open and eyes-closed upright standing balance performance was measured with no vibration, 30 Hz, and 40 Hz vibration of Gastrocnemius muscles. When vibratory stimulation was applied, changes in local-control performance manifested significant differences among the groups (p control performance were not significant between groups (p ≥ 0.19). Results suggest that local-control deficits are responsible for balance behavior alterations among elders at high fall risk and healthy individuals. This observation may be attributable to deterioration of short-latency reflexive loop in elders at high fall risk. On the other hand, we could not ascribe the balance alterations to problems related to central nervous system performance or long-latency responses. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Control rods

    International Nuclear Information System (INIS)

    Maruyama, Hiromi.

    1984-01-01

    Purpose: To realize effective utilization, cost reduction and weight reduction in neutron absorbing materials. Constitution: Residual amount of neutron absorbing material is averaged between the top end region and other regions of a control rod upon reaching to the control rod working life, by using a single kind of neutron absorbing material and increasing the amount of the neutron absorber material at the top end region of the control rod as compared with that in the other regions. Further, in a case of a control rod having control rod blades such as in a cross-like control rod, the amount of the neutron absorbing material is decreased in the middle portion than in the both end portions of the control rod blade along the transversal direction of the rod, so that the residual amount of the neutron absorbing material is balanced between the central region and both end regions upon reaching the working life of the control rod. (Yoshihara, H.)

  2. Control apparatus

    International Nuclear Information System (INIS)

    Doll, D.W.

    1977-01-01

    A nuclear reactor system is described in which flexible control rods are used to enable insertion of the control rods into guide holes in the core which are distributed over an area larger than the cross section of the control rod penetration in the reactor pressure vessel. Guide tubes extend from the penetration and fan out to the guide holes for guiding the control rods from the penetration to the guide holes

  3. Helicopter controllability

    OpenAIRE

    Carico, Dean

    1989-01-01

    Approved for public release; distribution is unlimited The concept of helicopter controllability is explained. A background study reviews helicopter development in the U.S. General helicopter configurations, linearized equations of motion, stability, and piloting requirements are discussed. Helicopter flight controls, handling qualities, and associated specification are reviewed. Analytical, simulation and flight test methods for evaluating helicopter automatic flight control systems ar...

  4. Gaining control

    NARCIS (Netherlands)

    Enden, van der E.; Laan, van der R.

    2008-01-01

    The article reports on the efforts of companies to find a solution for tax risk management, tax accounting and being in control. In trying to find a solution, companies work towards an integrated tax control framework (TCF), a tax risk management and control environment embedded in the internal

  5. Neurofuzzy Control

    DEFF Research Database (Denmark)

    Jantzen, Jan

    1997-01-01

    These notes are for a course in fuzzy control and neural networks. By neural networks we more precisely mean neurofuzzy systems rather than pure neural network theory. The notes are an extension to the existing notes on fuzzy control (Jantzen, Fuzzy Control, 1994)....

  6. Associational control

    DEFF Research Database (Denmark)

    Hvid, Helge Søndergaard; Lund, Henrik Lambrecht; Grosen, Sidsel Lond

    2010-01-01

    Over the last 30 years, the concept of control has had a central position in research into the psychological working environment. Control has been understood as individual autonomy and individual opportunities for development. This article examines whether the concept of control has the same key...

  7. Vestibular control of standing balance is enhanced with increased cognitive load.

    Science.gov (United States)

    McGeehan, Michael A; Woollacott, Marjorie H; Dalton, Brian H

    2017-04-01

    When cognitive load is elevated during a motor task, cortical inhibition and reaction time are increased; yet, standing balance control is often unchanged. This disconnect is likely explained by compensatory mechanisms within the balance system such as increased sensitivity of the vestibulomotor pathway. This study aimed to determine the effects of increased cognitive load on the vestibular control of standing balance. Participants stood blindfolded on a force plate with their head facing left and arms relaxed at their sides for two trials while exposed to continuous electrical vestibular stimulation (EVS). Participants either stood quietly or executed a cognitive task (double-digit arithmetic). Surface electromyography (EMG) and anterior-posterior ground-body forces (APF) were measured in order to evaluate vestibular-evoked balance responses in the frequency (coherence and gain) and time (cumulant density) domains. Total distance traveled for anterior-posterior center of pressure (COP) was assessed as a metric of balance variability. Despite similar distances traveled for COP, EVS-medial gastrocnemius (MG) EMG and EVS-APF coherence and EVS-TA EMG and EVS-MG EMG gain were elevated for multiple frequencies when standing with increased cognitive load. For the time domain, medium-latency peak amplitudes increased by 13-54% for EVS-APF and EVS-EMG relationships with the cognitive task compared to without. Peak short-latency amplitudes were unchanged. These results indicate that reliance on vestibular control of balance is enhanced when cognitive load is elevated. This augmented neural strategy may act to supplement divided cortical processing resources within the balance system and compensate for the acute neuromuscular modifications associated with increased cognitive demand.

  8. An investigation of motor learning during side-step cutting, design of a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Lemmink Koen APM

    2010-10-01

    Full Text Available Abstract Background Of all athletic knee injuries an anterior cruciate ligament (ACL rupture results in the longest time loss from sport. Regardless of the therapy chosen, conservative or reconstructive, athletes are often forced to reduce their level of physical activity and their involvement in sport. Moreover, a recent review reported prevalences of osteoarthritis ranging from 0% to 13% for patients with isolated ACL-deficient (ACL-D knees and respectively 21% to 48% in patients with combined injuries. The need for ACL injury prevention is clear. The identification of risk factors and the development of prevention strategies may therefore have widespread health and economic implications. The focus of this investigation is to assess the role of implicit and explicit motor learning in optimising the performance of a side-step-cutting task. Methods/design A randomized controlled laboratory study will be conducted. Healthy basketball players, females and males, 18 years and older, with no previous lower extremity injuries, playing at the highest recreational level will be included. Subjects will receive a dynamic feedback intervention. Kinematic and kinetic data of the hip, knee and ankle and EMG activity of the quadriceps, hamstrings and gastrocnemius will be recorded. Discussion Female athletes have a significantly higher risk of sustaining an ACL injury than male athletes. Poor biomechanical and neuromuscular control of the lower limb is suggested to be a primary risk factor of an ACL injury mechanism in females. This randomized controlled trial has been designed to investigate whether individual feedback on task performance appears to be an effective intervention method. Results and principles found in this study will be applied to future ACL injury prevention programs, which should maybe more focus on individual injury predisposition. Trial registration Trial registration number NTR2250.

  9. An investigation of motor learning during side-step cutting: design of a randomised controlled trial.

    Science.gov (United States)

    Benjaminse, Anne; Lemmink, Koen A P M; Diercks, Ron L; Otten, Bert

    2010-10-13

    Of all athletic knee injuries an anterior cruciate ligament (ACL) rupture results in the longest time loss from sport. Regardless of the therapy chosen, conservative or reconstructive, athletes are often forced to reduce their level of physical activity and their involvement in sport. Moreover, a recent review reported prevalences of osteoarthritis ranging from 0% to 13% for patients with isolated ACL-deficient (ACL-D) knees and respectively 21% to 48% in patients with combined injuries. The need for ACL injury prevention is clear. The identification of risk factors and the development of prevention strategies may therefore have widespread health and economic implications. The focus of this investigation is to assess the role of implicit and explicit motor learning in optimising the performance of a side-step-cutting task. A randomized controlled laboratory study will be conducted. Healthy basketball players, females and males, 18 years and older, with no previous lower extremity injuries, playing at the highest recreational level will be included. Subjects will receive a dynamic feedback intervention. Kinematic and kinetic data of the hip, knee and ankle and EMG activity of the quadriceps, hamstrings and gastrocnemius will be recorded. Female athletes have a significantly higher risk of sustaining an ACL injury than male athletes. Poor biomechanical and neuromuscular control of the lower limb is suggested to be a primary risk factor of an ACL injury mechanism in females. This randomized controlled trial has been designed to investigate whether individual feedback on task performance appears to be an effective intervention method. Results and principles found in this study will be applied to future ACL injury prevention programs, which should maybe more focus on individual injury predisposition. Trial registration number NTR2250.

  10. Effects of Neuromuscular Electrical Stimulation on the Frequency of Skeletal Muscle Cramps: A Prospective Controlled Clinical Trial.

    Science.gov (United States)

    Behringer, Michael; Harmsen, Jan-Frieder; Fasse, Alessandro; Mester, Joachim

    2017-11-22

    We investigated if neuromuscular electrical stimulation (NMES) of calf muscles prevents spontaneous calf cramps. In 19 individuals affected by more than or equal to one calf cramp per week the gastrocnemius of the predominantly affected leg was stimulated twice a week (intervention leg, IL) over six weeks (3 × 6 stimulation trains at 30 Hz above the individual cramp threshold frequency). The other leg served as control (CL). The participants were advised to record all spontaneous muscle cramps from two weeks before the intervention until two weeks after the last NMES session. The number of spontaneous calf cramps in the two weeks after the intervention was 78% lower (2.1 ± 6.8 cramps) in the stimulated (p cramps) in the unstimulated calves (p cramps; CL: 5.5 ± 12.7 cramps). Only in the IL, this improvement was accompanied by an increase in the cramp threshold frequency from 15.5 ± 8.5 Hz before the NMES intervention to 21.7 ± 12.4 Hz after the intervention. The severity of the remaining calf cramps tended to be lower in both legs after the intervention. The applied stimulation protocol seems to provide an effective prevention strategy in individuals affected by regular calf cramps. © 2017 International Neuromodulation Society.

  11. Heme arginate improves reperfusion patterns after ischemia: a randomized, placebo-controlled trial in healthy male subjects

    Directory of Open Access Journals (Sweden)

    Andreas Martin

    2012-08-01

    Full Text Available Abstract Background Heme arginate can induce heme oxygenase-1 to protect tissue against ischemia-reperfusion injury. Blood oxygen level dependent (BOLD functional magnetic resonance imaging measures changes in tissue oxygenation with a high spatial and temporal resolution. BOLD imaging was applied to test the effect of heme arginate on experimental ischemia reperfusion injury in the calf muscles. Methods A two period, controlled, observer blinded, crossover trial was performed in 12 healthy male subjects. Heme arginate (1 mg/kg body weight or placebo were infused 24 h prior to a 20 min leg ischemia induced by a thigh cuff. 3 Tesla BOLD-imaging of the calf was performed and signal time courses from soleus, gastrocnemius and tibialis anterior muscle were available from 11 participants for technical reasons. Results Peak reactive hyperemia signal of the musculature was significantly increased and occurred earlier after heme arginate compared to placebo (106.2±0.6% at 175±16s vs. 104.5±0.6% at 221±19s; p = 0.025 for peak reperfusion and p = 0.012 for time to peak. Conclusions A single high dose of heme arginate improves reperfusion patterns during ischemia reperfusion injury in humans. BOLD sensitive, functional MRI is applicable for the assessment of experimental ischemia reperfusion injury in skeletal muscle. Trial registration ClinicalTrials: NCT01461512 EudraCT: 2008-006967-35

  12. Control rod

    International Nuclear Information System (INIS)

    Takahashi, Akio.

    1982-01-01

    Purpose: To prevent distortion in control rod elements such as cladding tubes by decreasing the temperature difference between them. Constitution: In the case of housing a plurality of control rod elements in a protection pipe, flow rate control members are disposed in the protection pipe to equalize the flow resistance in each of coolant flow passages formed between the control rod elements and between the control rod elements and the inner surface of the protection pipe, to thereby unify the flow rate of the coolants flowing through these coolant flowing passages. Accordingly, each of the control rod elements can be cooled uniformly to thereby unify the temperature distribution and avoid the distortion in the cladding tubes, which may be resulted from bending due to the difference in thermal expansion and ununiform swelling due to the temperature difference. (Aizawa, K.)

  13. Optimal control

    CERN Document Server

    Aschepkov, Leonid T; Kim, Taekyun; Agarwal, Ravi P

    2016-01-01

    This book is based on lectures from a one-year course at the Far Eastern Federal University (Vladivostok, Russia) as well as on workshops on optimal control offered to students at various mathematical departments at the university level. The main themes of the theory of linear and nonlinear systems are considered, including the basic problem of establishing the necessary and sufficient conditions of optimal processes. In the first part of the course, the theory of linear control systems is constructed on the basis of the separation theorem and the concept of a reachability set. The authors prove the closure of a reachability set in the class of piecewise continuous controls, and the problems of controllability, observability, identification, performance and terminal control are also considered. The second part of the course is devoted to nonlinear control systems. Using the method of variations and the Lagrange multipliers rule of nonlinear problems, the authors prove the Pontryagin maximum principle for prob...

  14. Pressure Controller

    Science.gov (United States)

    1981-01-01

    EPIC is Electronic Pressure Indicating Controller produced by North American Manufacturing Company. It is a high-sensitivity device for improving combustion efficiency in industrial furnaces that interprets a signal from a pressure transducer on a furnace and regulates furnace pressure accordingly. A controller can provide savings of from five to 25 percent of an industrial user's annual furnace fuel bill.

  15. Taking Control

    Centers for Disease Control (CDC) Podcasts

    2007-11-01

    This podcast gives action steps and reasons to control diabetes.  Created: 11/1/2007 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 11/2/2007.

  16. Control Theory.

    Science.gov (United States)

    Toso, Robert B.

    2000-01-01

    Inspired by William Glasser's Reality Therapy ideas, Control Theory (CT) is a disciplinary approach that stresses people's ability to control only their own behavior, based on internal motivations to satisfy five basic needs. At one North Dakota high school, CT-trained teachers are the program's best recruiters. (MLH)

  17. Comparação da ativação mioelétrica do glúteo máximo e bíceps femoral entre os agachamentos paralelo e com passada à frente Comparación de la activación mioeléctrica de los glúteos y bíceps femoral entre las sentadillas con los pies paralelos y los pies uno frente al otro Comparison of myoelectric activity of gluteus maximus and biceps femoris between parallel and lunge squat

    Directory of Open Access Journals (Sweden)

    Gustavo Leporace

    2012-09-01

    .The purpose of this study was to compare the EMG of the gluteus maximus and biceps femoris between the lunge and the parallel squat. Seven subjects, with experience in strength training, performed eight repetitions of the parallel squat (PS and the lunge (LU with an overload corresponding to 50% of body mass. The EMG of the gluteus maximus and biceps femoris was captured, filtered by a forth order Butterworth filter (20-400 Hz and calculated RMS values. The Wilcoxon Ranked test was used to compare the normalized EMG of each muscle between the two exercises. Both the biceps femoris (p = 0.041 and the gluteus maximus (p = 0.0059 showed increased activation in LU compared to the PS. Despite the moderate activation in both exercises, ranging from 25% to 45%, the myoelectric response of the analyzed muscles was higher, for the participants, in the lunge exercise.

  18. Comparison of the effect of focused and radial extracorporeal shock waves on spastic equinus in patients with stroke: a randomized controlled trial.

    Science.gov (United States)

    Wu, Yah-Ting; Chang, Chih-Ning; Chen, Yi-Min; Hu, Gwo-Chi

    2017-10-25

    Recent studies have suggested that either focused or radial shock wave therapy is an effect method for the treatment of spasticity in patients with stroke. However, no previous study compared these two types of extracorporeal shock wave on spasticity in patients with stroke. This study aimed to compare the effect of focused and radial shock wave therapy for the treatment of spastic equinus in patients with stroke. Randomized control trial. Outpatient rehabilitation center in a medical center. 32 stroke patients with spastic equinus (18 males and 14 women; mean age, 60.1±10.6 years). Patients were randomly assigned to receive three sessions of either focused or radial shock wave therapy at 1-week intervals. The intensities that were used during focused shock wave therapy (0.12 mJ/mm2) and radial shock wave therapy (2.4 bar) were comparable. The patients were evaluated at baseline and at 1, 4, and 8 weeks after the final shockwave treatment. The primary outcome measure was change of modified Ashworth scale score of gastrocnemius muscle. The secondary outcome measures were Tardieu scale, ankle passive range of motion, dynamic foot contact area and gait speed. A linear mixed model with repeated measures was used to compare each outcome measure between the two groups. Both groups improved significantly in terms of modified Ashworth scale score and Tardieu scale, and no differences were found between the two groups. In terms of ankle passive range of motion and plantar contact area during gait, the radial shock wave therapy yielded a significantly greater improvement than the focused shock wave therapy. No significant changes were observed in gait speed in either group. Our study suggested that focused and radial shock wave therapy resulted in similar significant improvements in the modified Ashworth scale score and Tardieu scale, but those in the radial shock wave therapy group experienced greater improvements in the ankle passive range of motion and plantar contact

  19. Describing control

    International Nuclear Information System (INIS)

    Fouet, J.M.; Starynkevitch, B.

    1987-01-01

    Incremental development and maintenance of large systems imply that control be clearly separated from knowledge. Finding efficient control for a given class of knowledge is itself a matter of expertise, to which knowledge-based methods may and should be applied. We present here two attempts at building root systems that may later be tuned by knowledge engineers, using the semantics of each particular application. These systems are given heuristics in a declarative manner, which they use to control the application of heuristics. Eventually, some heuristics may be used to compile others (or themselves) into efficient pieces of programmed code

  20. Institutional Controls

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset consists of institutional control data from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different...

  1. CONTROL SYSTEM

    Science.gov (United States)

    Shannon, R.H.; Williamson, H.E.

    1962-10-30

    A boiling water type nuclear reactor power system having improved means of control is described. These means include provisions for either heating the coolant-moderator prior to entry into the reactor or shunting the coolantmoderator around the heating means in response to the demand from the heat engine. These provisions are in addition to means for withdrawing the control rods from the reactor. (AEC)

  2. Effects of concurrent training on oxidative capacity in rat gastrocnemius muscle

    NARCIS (Netherlands)

    Furrer, R.; Bravenboer, N.; Kos, D.; Lips, P.; de Haan, A.; Jaspers, R.T.

    2013-01-01

    PURPOSE: Training for improvement of oxidative capacity of muscle fibers may be attenuated when concurrently training for peak power. However, because of fiber type-specific recruitment, such attenuation may only account for high-oxidative muscle fibers. Here, we investigate the effects of

  3. Effects of growth on geometry of gastrocnemius muscle in children: a three-dimensional ultrasound analysis

    NARCIS (Netherlands)

    Benard, M.R.; Harlaar, J.; Becher, J.G.; Huijing, P.A.; Jaspers, R.T.

    2011-01-01

    During development, muscle growth is usually finely adapted to meet functional demands in daily activities. However, how muscle geometry changes in typically developing children and how these changes are related to functional and mechanical properties is largely unknown. In rodents, longitudinal

  4. The effects of gastrocnemius-soleus muscle forces on ankle biomechanics during triple arthrodesis

    DEFF Research Database (Denmark)

    Hejazi, Shima; Rouhi, Gholamreza; Rasmussen, John

    2017-01-01

    This paper presents a finite element model of the ankle, taking into account the effects of muscle forces, determined by a musculoskeletal analysis, to investigate the contact stress distribution in the tibio-talar joint in patients with triple arthrodesis and in normal subjects. Forces of major...... ankle muscles were simulated and corresponded well with the trend of ‎their EMG signals. These forces were applied to the finite element model to obtain stress distributions for patients with triple arthrodesis and normal subjects in three stages of the gait cycle, i.e. heel strike, midstance and heel...

  5. Influence of a low-frequency magnetic field on the 133Xe clearance of the gastrocnemius

    International Nuclear Information System (INIS)

    Stroehmann, F.; Strangfeld, D.; Conradi, E.

    1985-01-01

    In 14 patients with disturbances of the arterial blood supply the influence of a 50 Hz changing magnetic field of 24 mT on the microcirculation of the musculature was tested by means of 133 Xe clearance. An influence of the magnetic field could not be proved. (author)

  6. Rodent Research-1 (RR1) NASA Validation Flight: Mouse gastrocnemius muscle transcriptomic proteomic and epigenomic data

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA s Rodent Research (RR) project is playing a critical role in advancing biomedical research on the physiological effects of space environments. Due to the...

  7. Effect of meal temperature on the frequency of gastric myoelectrical activity

    NARCIS (Netherlands)

    Verhagen, M. A.; Luijk, H. D.; Samsom, M.; Smout, A. J.

    1998-01-01

    It was hypothesized that the transient post-prandial decrease of the dominant frequency in the electrogastrogram (EGG) is related to the temperature of the meal. In a randomized three-period cross-over design. EGG recordings were made in 10 healthy volunteers. A liquid meal (36 kcal, 300 mL) was

  8. At-home computer-aided myoelectric training system for wrist prosthesis

    OpenAIRE

    Vilouras, Anastasios; Heidari, Hadi; Navaraj, William Taube; Dahiya, Ravinder

    2016-01-01

    Development of tools for rehabilitation and restoration of the movement after amputation can benefit from the real time interactive virtual animation model of the human hand. Here, we report a computer-aided training/learning system for wrist disarticulated amputees, using the open source integrated development environment called “Processing”. This work also presents the development of a low-cost surface Electro-MyoGraphic (sEMG) interface, which is an ideal tool for training and rehabilitati...

  9. Operator Alertness/Workload Assessment Using Stochastic Model-Based Analysis of Myoelectric Signals

    Science.gov (United States)

    1984-04-30

    Systems; Forward Technology, Inc.; Plexus ; and Dual Systems Corp. Our criteria for selecting the system was three-fold: cost, availability and support by...maskable interrupts, the only way to * do this is to use an interrupt channel that can’t be locked out -- namely the nonmaskable interrupt. A driver

  10. Time and frequency domain analysis of surface myoelectric signals during electrically-elicited cramps.

    Science.gov (United States)

    Minetto, M A; Botter, A; De Grandis, D; Merletti, R

    2009-02-01

    To examine if different frequencies of electrical stimulation trigger different sized cramps in the abductor hallucis muscle and to analyze their surface electromyographic (EMG) behaviour in both time and frequency domains. Fifteen subjects were studied. Stimulation trains of 150 pulses were applied to the muscle motor point. Frequency was increased (starting from 4pps with 2-pps steps) until a cramp developed. Current intensity was 30% higher than that eliciting maximal M-waves. After the first cramp ("threshold cramp"), a 30-minute rest was provided before a second cramp ("above-threshold cramp") was elicited with a frequency increased by 50% with respect to that eliciting the first cramp. We found greater EMG amplitude and a compression of the power spectrum for above-threshold cramps with respect to threshold cramps. M-wave changes (ranging between small decreases of M-wave amplitude to complete M-wave disappearance) occurred and progressively increased throughout stimulation trains. Significant positive correlations were found between estimates of EMG amplitude during cramps and estimated reductions of M-wave amplitude. Varying frequencies of electrical stimulation triggered different sized cramps. Moreover, decreases in M-wave amplitude were observed during both threshold and above-threshold stimulations. The choice of the stimulation frequency has relevance for optimizing electrical stimulation protocols for the study of muscle cramps in both healthy and pathological subjects.

  11. Grasp specific and user friendly interface design for myoelectric hand prostheses.

    Science.gov (United States)

    Mohammadi, Alireza; Lavranos, Jim; Howe, Rob; Choong, Peter; Oetomo, Denny

    2017-07-01

    This paper presents the design and characterisation of a hand prosthesis and its user interface, focusing on performing the most commonly used grasps in activities of daily living (ADLs). Since the operation of a multi-articulated powered hand prosthesis is difficult to learn and master, there is a significant rate of abandonment by amputees in preference for simpler devices. In choosing so, amputees chose to live with fewer features in their prosthesis that would more reliably perform the basic operations. In this paper, we look simultaneously at a hand prosthesis design method that aims for a small number of grasps, a low complexity user interface and an alternative method to the current use of EMG as a preshape selection method through the use of a simple button; to enable amputees to get to and execute the intended hand movements intuitively, quickly and reliably. An experiment is reported at the end of the paper comparing the speed and accuracy with which able-bodied naive subjects are able to select the intended preshapes through the use of a simplified EMG method and a simple button. It is shown that the button was significantly superior in the speed of successful task completion and marginally superior in accuracy (success of first attempt).

  12. Quality function deployment QFD: benefits and limitations when applied to designing myoelectric prosthesis hand

    Directory of Open Access Journals (Sweden)

    Erika Sofía Olaya Escobar

    2005-01-01

    Full Text Available Quality, cost and time spent in developing products have a direct impact on a company's productivity, market share and profitability. Greater attention must be paid to quality and quicker responses made as customers become more aware of satisfying their longings. This means that a company must be first in delivering a product or service which customers desire if ti wishes to gain and maintain market share. A company's market share and profit margin will depend on the balance and optimisation achieved between quality, cost and time. It is thus important to implant a method like Quality Function Deployment (QFD leading to planning product development during eartly design stages and consequently establish such equilibrium. This article's purpose is to present benefits and limitations regarding QFD; one should be aware of them and QFD development when identifying the most viable to be applied according to each company's inherent characteristics.

  13. Spectral properties of multiple myoelectric signals: New insights into the neural origin of muscle synergies.

    Science.gov (United States)

    Frère, Julien

    2017-07-04

    It is still unclear if muscle synergies reflect neural strategies or mirror the underlying mechanical constraints. Therefore, this study aimed to verify the consistency of muscle groupings between the synergies based on the linear envelope (LE) of muscle activities and those incorporating the time-frequency (TF) features of the electromyographic (EMG) signals. Twelve healthy participants performed six 20-m walking trials at a comfort and fast self-selected speed, while the activity of eleven lower limb muscles was recorded by means of surface EMG. Wavelet-transformed EMG was used to obtain the TF pattern and muscle synergies were extracted by non-negative matrix factorization. When five muscle synergies were extracted, both methods defined similar muscle groupings whatever the walking speed. When accounting the reconstruction level of the initial dataset, a new TF synergy emerged. This new synergy dissociated the activity of the rectus femoris from those of the vastii muscles (synergy #1) and from the one of the tensor fascia latae (synergy #5). Overall, extracting TF muscle synergies supports the neural origin of muscle synergies and provides an opportunity to distinguish between prescriptive and descriptive muscle synergies. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Analysis of Large Array Surface Myoelectric Potentials for the Low Back Muscles

    National Research Council Canada - National Science Library

    Reger, Steven

    2001-01-01

    .... The surface EMC distribution from the low back of 161 healthy and 44 acute LBP subjects were collected in three minimum stress postural positions including standing, 20 degrees of lumbar flexion...

  15. Management control or control management?

    Directory of Open Access Journals (Sweden)

    José Carlos Dextre Flores

    2012-12-01

    Full Text Available The attempt to answer the title of this article frames the analysis of the concept of control as a key role of the management, which any entity applies in pursuit of its institutional fulfillment. The control intervention in the development of the activities carried out by organizations to achieve the planned objectives of economic, social or political order constitutes its core business, as it seeks to ensure that those activities—operations and processes—are conducted safely, continuous and reliable. This applies both to those who constitute the organization and those who have expectations of management efficiency and the effectiveness of the expected results. In this paper, on the one hand, we propose to revise the control concept and its application in the exercise of monitoring the management performance; on the other hand, we seek to show how control should be managed to achieve efficient and effective results.

  16. Resveratrol Improves Glycemic Control in Type 2 Diabetic Obese Mice by Regulating Glucose Transporter Expression in Skeletal Muscle and Liver.

    Science.gov (United States)

    Yonamine, Caio Y; Pinheiro-Machado, Erika; Michalani, Maria L; Alves-Wagner, Ana B; Esteves, João V; Freitas, Helayne S; Machado, Ubiratan F

    2017-07-14

    Insulin resistance participates in the glycaemic control disruption in type 2 diabetes mellitus (T2DM), by reducing muscle glucose influx and increasing liver glucose efflux. GLUT4 ( Slc2a4 gene) and GLUT2 ( Slc2a2 gene) proteins play a fundamental role in the muscle and liver glucose fluxes, respectively. Resveratrol is a polyphenol suggested to have an insulin sensitizer effect; however, this effect, and related mechanisms, have not been clearly demonstrated in T2DM. We hypothesized that resveratrol can improve glycaemic control by restoring GLUT4 and GLUT2 expression in muscle and liver. Mice were rendered obese T2DM in adult life by neonatal injection of monosodium glutamate. Then, T2DM mice were treated with resveratrol for 60 days or not. Glycaemic homeostasis, GLUT4, GLUT2, and SIRT1 (sirtuin 1) proteins (Western blotting); Slc2a4 , Slc2a2 , and Pck1 (key gluconeogenic enzyme codifier) mRNAs (RT-qPCR); and hepatic glucose efflux were analysed. T2DM mice revealed: high plasma concentration of glucose, fructosamine, and insulin; insulin resistance (insulin tolerance test); decreased Slc2a4 /GLUT4 content in gastrocnemius and increased Slc2a2 /GLUT2 content in liver; and increased Pck1 mRNA and gluconeogenic activity (pyruvate tolerance test) in liver. All alterations were restored by resveratrol treatment. Additionally, in both muscle and liver, resveratrol increased SIRT1 nuclear content, which must participate in gene expression regulations. In sum, the results indisputably reveals that resveratrol improves glycaemic control in T2DM, and that involves an increase in muscle Slc2a4 /GLUT4 and a decrease in liver Slc2a2 /GLUT2 expression. This study contributes to our understanding how resveratrol might be prescribed for T2DM according to the principles of evidence-based medicine.

  17. Postural control deficits in people with fibromyalgia: a pilot study

    Science.gov (United States)

    2011-01-01

    Introduction Postural instability and falls are increasingly recognized problems in patients with fibromyalgia (FM). The purpose of this study was to determine whether FM patients, compared to age-matched healthy controls (HCs), have differences in dynamic posturography, including sensory, motor, and limits of stability. We further sought to determine whether postural instability is associated with strength, proprioception and lower-extremity myofascial trigger points (MTPs); FM symptoms and physical function; dyscognition; balance confidence; and medication use. Last, we evaluated self-reported of falls over the past six months. Methods In this cross-sectional study, we compared middle-aged FM patients and age-matched HCs who underwent computerized dynamic posturography testing and completed the Fibromyalgia Impact Questionnaire-Revised (FIQR) and balance and fall questionnaires. All subjects underwent a neurological and musculoskeletal examination. Descriptive statistics were used to characterize the sample and explore the relationships between variables. The relationships between subjective, clinical and objective variables were evaluated by correlation and regression analyses. Results Twenty-five FM patients and twenty-seven HCs (combined mean age ± standard deviation (SD): 48.6 ± 9.7 years) completed testing. FM patients scored statistically lower on composite sensory organization tests (primary outcome; P < 0.010), as well as with regard to vestibular, visual and somatosensory ratio scores on dynamic posturography. Balance confidence was significantly different between groups, with FM patients reporting less confidence than HCs (mean ± SD: 81.24 ± 19.52 vs. 98.52 ± 2.45; P < 0.001). Interestingly, 76% to 84% of FM patients had gastrocnemius and/or anterior tibialis MTPs. Postural stability was best predicted by dyscognition, FIQR score and body mass index. Regarding falls, 3 (11%) of 27 HCs had fallen only once during the past 6 months, whereas 18 (72

  18. Slackline training and neuromuscular performance in seniors: A randomized controlled trial.

    Science.gov (United States)

    Donath, L; Roth, R; Zahner, L; Faude, O

    2016-03-01

    Slackline training (balancing on nylon ribbons) has been shown to improve neuromuscular performance in children and adults. Comparable studies in seniors are lacking. Thus, 32 seniors were randomly assigned [strata: age, gender, physical activity (PA)] to an intervention [INT; n = 16, age: 65 ± 4 years, PA: 9 ± 5 h/week] or control [CON, n = 16, age: 63 ± 4 years, PA: 8 ± 4 h/week] group. Slackline training was given for 6 weeks (3 times per week, attendance 97%). Static and slackline standing balance performance, force development, and maximal strength of the ankle muscles were assessed before and after slackline training. Muscle activity (lower limb and trunk) was recorded during balance testing. Moderate to large group × time interactions (0.02 slackline standing times (INT: left, +278%, P = 0.02; right, +328%, P = 0.03; tandem, +94%, P = 0.007) and muscle activity during single-limb slackline standing [INT: right: rectus abdominis (RA), P = 0.003, -15%; multifidus (MF), P = 0.01, -15%; left: tibialis anterior (TIB), P = 0.03, -12%; soleus (SOL), P = 0.006, -18%; RA, P = 0.04, -11%; MF, P = 0.01, -16%; gastrocnemius medialis (GM), P = 0.02, -19%]. Static balance performance, ankle strength, and power were not affected. Slackline training induced large task-specific improvements of slackline standing performance accompanied with reductions of lower limb and trunk muscle activity. Transfer effects to static balance and strength measures seem limited. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. CYCLE CONTROL

    African Journals Online (AJOL)

    changed to gestodene. Although large- scale comparative trials are needed to confirm this finding, evidence suggests that cycle control with gestodene is better than for monophasic preparations containing desogestrel, norgestimate or levonorgestrel,10 as well as for levonorg- estrel-or norethisterone-containing triphasics.

  20. TOBACCO CONTROL

    International Development Research Centre (IDRC) Digital Library (Canada)

    of tobacco control laws, and limited public awareness about the hazards of tobacco com- bine to create a growing health crisis. Currently, 70% of .... exposure to tobacco smoke in “workplaces, public transport, and indoor public places.” At the time, Guatemalan law prohibited smoking in schools and hospitals — but had only ...

  1. Rent Control

    African Journals Online (AJOL)

    macuser

    The article considers the nature of rent control as a regulatory law that should ideally accord with the ..... for instance to terminate a periodic tenancy the landlord might lose some commercial gain, if anything at all. ...... the tenant with a proprietary interest but rather affords the tenant with a "status of irremovability". A statutory ...

  2. Factors in delayed onset muscular soreness of man

    NARCIS (Netherlands)

    Bobbert, M F; Hollander, A P; Huijing, P A

    In this study 11 subjects performed exercise resulting in delayed onset muscular soreness in m. gastrocnemius with one leg, the experimental leg. The other leg served as control. Pre-exercise and 24, 48 and 72 h postexercise, soreness perception, resting EMG level of m. gastrocnemius, and volume and

  3. COPD - control drugs

    Science.gov (United States)

    Chronic obstructive pulmonary disease - control drugs; Bronchodilators - COPD - control drugs; Beta agonist inhaler - COPD - control drugs; Anticholinergic inhaler - COPD - control drugs; Long-acting inhaler - COPD - control drugs; ...

  4. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  5. Vehicle Controller

    Science.gov (United States)

    1985-01-01

    UNISTICK is an airplane-like joystick being developed by Johnson Engineering under NASA and VA sponsorship. It allows a driver to control a vehicle with one hand, and is based upon technology developed for the Apollo Lunar Landings of the 1970's. It allows severely handicapped drivers to operate an automobile or van easily. The system is expected to be in production by March 1986.

  6. Losing control

    DEFF Research Database (Denmark)

    Leppink, Eric; Odlaug, Brian Lawrence; Lust, Katherine

    2014-01-01

    OBJECTIVE: Assaultive behaviors are common among young people and have been associated with a range of other unhealthy, impulsive behaviors such as substance use and problem gambling. This study sought to determine the predictive ability of single assaultive incidents for impulse control disorders...... morbidity. Additional research is needed to develop specific prevention and treatment strategies for young adults attending college who report problems with assaultive behaviors....

  7. Control rod

    International Nuclear Information System (INIS)

    Fukumoto, Takashi; Hirakawa, Hiromasa; Kawashima, Norio; Goto, Yasuyuki.

    1994-01-01

    Neutron absorbers are contained in a tubular member comprising, integrally a tubular portion and four corners disposed at the outer circumference of the tubular portion at every 90deg, to provide a neutron absorbing tube. A plurality of neutron absorbing tubes are arranged in parallel in the lateral direction, and adjacent corners are joined, into a blade to constitute a control rod. Such a control rod has a great structural strength, simple in the structure and relatively light in weight and can contain a great amount of neutron absorbers. Upon formation of the control rod by arranging the blades in a cross-like shape, at least a portion thereof is constituted with short neutron absorbing tubes shorter than the entire length of the blade, and gaps are formed at positions in adjacent in the axial direction. With such a constitution, there is no worry that a wing end of the blade collides against or be abraded with a fuel channel box or a fuel support. Even if fuel channels are vibrated upon scram of the reactor, such as occurrence of earthquakes, it can be inserted to the reactor easily. (N.H.)

  8. Environmental control.

    Science.gov (United States)

    Squillace, S P

    1992-12-01

    Environmental control measures help eliminate triggers that initiate the allergic reaction and reduce the conditions that sustain it. The most frequent offenders are the ubiquitous dust mites, which are ideally suited to living in the home environment. Control measures consist of minimizing their reservoirs in the patient's bedding, carpets, and upholstered furniture; decreasing humidity; and using acaricides. Cats are the source of another important indoor allergen that becomes and stays airborne as small particles. Removal of the animal (or washing it weekly) and the use of high-efficiency particulate air filters for air ducts and vacuum cleaners are useful in reducing dust mite and cat allergens. Dogs and rodents also produce allergens offensive to the sensitized patient and should be removed or relegated outdoors. Cockroaches have become an increasingly prevalent source of allergens responsible for asthma and rhinitis. Their removal is the focus of research, because current control measures are usually inadequate. Molds, which thrive in any moist environment, produce allergens. Closed windows prevent further influx of outdoor molds and pollens, whereas those harbored indoors, including those residing on plants, should be eliminated.

  9. Dynamic ankle control in athletes with ankle instability during sports maneuvers.

    Science.gov (United States)

    Lin, Cheng-Feng; Chen, Chin-Yang; Lin, Chia-Wei

    2011-09-01

    Ankle sprain is a common sports injury. While the effects of static constraints in stabilizing the ankle joint are relatively well understood, those of dynamic constraints are less clear and require further investigation. This study was undertaken to evaluate the dynamic stability of the ankle joint during the landing phase of running and stop-jump maneuvers in athletes with and without chronic ankle instability (CAI). Controlled laboratory study. Fifteen athletes with CAI and 15 age-matched athletes without CAI performed running and stop-jump landing tasks. The dynamic ankle joint stiffness, tibialis anterior (TA)/peroneus longus (PL) and TA/gastrocnemius lateralis (GL) co-contraction indices, ankle joint angle, and root-mean-square (RMS) of the TA, PL, and GL electromyographic signals were measured during each task. During running, the CAI group exhibited a greater ankle inversion angle than the control group in the pre-landing phase (P = .012-.042) and a lower dynamic ankle joint stiffness in the post-landing phase (CAI: 0.109 ± 0.039 N·m/deg; control: 0.150 ± 0.068 N·m/deg; P = .048). In the stop-jump landing task, athletes with CAI had a significantly lower TA/PL co-contraction index during the pre-landing phase (CAI: 49.1 ± 19; control: 64.8 ± 16; P = .009). In addition, the CAI group exhibited a greater ankle inversion (P = .049), a lower peak eversion (P = .04), and a smaller RMS of the PL electromyographic signal in the post-landing phase (CAI: 0.73 ± 0.32; control: 0.51 ± 0.22; P = .04). Athletes with CAI had a relatively inverted ankle, reduced muscle co-contraction, and a lower dynamic stiffness in the ankle joint during the landing phase of sports maneuvers and this may jeopardize the stability of the ankle. Sports training or rehabilitation programs should differentiate between the pre-landing and post-landing phases of sports maneuvers, and should educate athletes to land with an appropriate ankle position and muscle recruitment.

  10. The effect of shoe design and lateral wedges on knee load and neuromuscular control in healthy subjects during walking

    DEFF Research Database (Denmark)

    Mølgaard, Carsten Møller; Kersting, Uwe G.

    2013-01-01

    and second peak knee adduction moments. However, the variability of this moment between shoe designs was of similar magnitude as the effect of laterally wedged insoles. Only marginal changes in muscle activity for gastrocnemius when walking with the wedged Oxford shoe were revealed. Conclusion: Lateral...

  11. Control Prenatal

    Directory of Open Access Journals (Sweden)

    P. Susana Aguilera, DRA.

    2014-11-01

    Full Text Available Los principales objetivos del control prenatal son identificar aquellos pacientes de mayor riesgo, con el fin de realizar intervenciones en forma oportuna que permitan prevenir dichos riesgos y así lograr un buen resultado perinatal. Esto se realiza a través de la historia médica y reproductiva de la mujer, el examen físico, la realización de algunos exámenes de laboratorio y exámenes de ultrasonido. Además es importante promover estilos de vida saludables, la suplementación de ácido fólico, una consejería nutricional y educación al respecto.

  12. Control rod

    International Nuclear Information System (INIS)

    Igarashi, Takao; Sugawara, Satoshi; Yoshimoto, Yuichiro; Saito, Shozo; Fukumoto, Takashi.

    1987-01-01

    Purpose: To reduce the weight and thereby obtain satisfactory operationability of control rods by combining absorbing nuclear chain type neutron absorbers and conventional type neutron absorbers in the axial direction of blades. Constitution: Neutron absorber rods and long life type neutron absorber rods are disposed in a tie rod and a sheath. The neutron absorber rod comprises a poison tube made of stainless steels and packed with B 4 C powder. The long life type neutron absorber rod is prepared by packing B-10 enriched boron carbide powder into a hafnium metal rod, hafnium pipe, europium and stainless made poison tube. Since the long life type absorber rod uses HF as the absorbing nuclear chain type neutron absorber, it absorbs neutrons to form new neutron absorbers to increase the nuclear life. (Yoshino, Y.)

  13. Control Valve

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Wayne R.

    2018-03-20

    A control valve includes a first conduit having a first inlet and a first outlet and defining a first passage; a second conduit having a second inlet and a second outlet and defining a second passage, the second conduit extending into the first passage such that the second inlet is located within the first passage; and a valve plate disposed pivotably within the first passage, the valve plate defining a valve plate surface. Pivoting of the valve plate within the first passage varies flow from the first inlet to the first outlet and the valve plate is pivotal between a first position and a second position such that in the first position the valve plate substantially prevents fluid communication between the first passage and the second passage and such that in the second position the valve plate permits fluid communication between the first passage and the second passage.

  14. A murine model of a novel surgical architecture for proprioceptive muscle feedback and its potential application to control of advanced limb prostheses

    Science.gov (United States)

    Clites, Tyler R.; Carty, Matthew J.; Srinivasan, Shriya; Zorzos, Anthony N.; Herr, Hugh M.

    2017-06-01

    Objective. Proprioceptive mechanisms play a critical role in both reflexive and volitional lower extremity control. Significant strides have been made in the development of bionic limbs that are capable of bi-directional communication with the peripheral nervous system, but none of these systems have been capable of providing physiologically-relevant muscle-based proprioceptive feedback through natural neural pathways. In this study, we present the agonist-antagonist myoneural interface (AMI), a surgical approach with the capacity to provide graded kinesthetic feedback from a prosthesis through mechanical activation of native mechanoreceptors within residual agonist-antagonist muscle pairs. Approach. (1) Sonomicrometery and electroneurography measurement systems were validated using a servo-based muscle tensioning system. (2) A heuristic controller was implemented to modulate functional electrical stimulation of an agonist muscle, using sonomicrometric measurements of stretch from a mechanically-coupled antagonist muscle as feedback. (3) One AMI was surgically constructed in the hindlimb of each rat. (4) The gastrocnemius-soleus complex of the rat was cycled through a series of ramp-and-hold stretches in two different muscle architectures: native (physiologically-intact) and AMI (modified). Integrated electroneurography from the tibial nerve was compared across the two architectures. Main results. Correlation between stretch and afferent signal demonstrated that the AMI is capable of provoking graded afferent signals in response to ramp-and-hold stretches, in a manner similar to the native muscle architecture. The response magnitude in the AMI was reduced when compared to the native architecture, likely due to lower stretch amplitudes. The closed-loop control system showed robustness at high stretch magnitudes, with some oscillation at low stretch magnitudes. Significance. These results indicate that the AMI has the potential to communicate meaningful kinesthetic

  15. Consequences of simulated car driving at constant high speed on the sensorimotor control of leg muscles and the braking response.

    Science.gov (United States)

    Jammes, Yves; Behr, Michel; Weber, Jean P; Berdah, Stephane

    2017-11-01

    Due to the increase in time spent seated in cars, there is a risk of fatigue of the leg muscles which adjust the force exerted on the accelerator pedal. Any change in their sensorimotor control could lengthen the response to emergency braking. Fourteen healthy male subjects (mean age: 42 ± 4 years) were explored. Before and after a 1-h driving trial at 120 km h -1 , we measured the braking response, the maximal leg extension and foot inversion forces, the tonic vibratory response (TVR) in gastrocnemius medialis (GM) and tibialis anterior (TA) muscles to explore the myotatic reflex, and the Hoffmann reflex (H-reflex). During driving, surface electromyograms (EMGs) of GM and TA were recorded and the ratio between high (H) and low (L) EMG energies allowed to evaluate the recruitment of high- and low-frequency motor unit discharges. During driving, the H/L ratio decreased in TA, whereas modest and often no significant H/L changes occurred in GM muscle. After driving, the maximal foot inversion force decreased (-19%), while the leg extension force did not vary. Reduced TVR amplitude (-29%) was measured in TA, but no H-reflex changes were noted. The braking reaction time was not modified after the driving trial. Driving at constant elevated speed reduced the myotatic reflex and the recruitment of motor units in TA muscle. The corresponding changes were rarely present in the GM muscle that plays a key role in the braking response, and this could explain the absence of a reduced braking reaction time. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  16. Overload and neovascularization of Achilles tendons in young artistic and rhythmic gymnasts compared with controls: an observational study.

    Science.gov (United States)

    Notarnicola, A; Maccagnano, G; Di Leo, M; Tafuri, S; Moretti, B

    2014-08-01

    The incidence of Achilles tendinopathy is very high in young female gymnasts (17.5 %). According to literature, ecography screenings show the tendons thickening, but at the same time it does not reveal a direct link to the clinical picture. The neovessels are involved in the pathophysiological process of Achilles tendinopathy. For this reason, we wanted to verify there between perfusion tendon values and the type of sport activity. We performed a clinical observational study monitoring the oximetry of the Achilles tendon and the epidemiological data of 52 elite female (artistic and rhythmic) gymnasts versus 21 age-matched controls. Analyzing the main limb, we revealed statistically higher oximetry values in the artistic gymnasts group (69.5 %) compared to the rhythmic gymnasts group (67.1 %) (t = 2.13; p = 0.01) and the sedentary group (66.2 %) (t = 2.70; p = 0.004), but we did not find any differences between rhythmic gymnasts group and the sedentary group (t = 0.68; p = 0.24). The multiple logistic regression model highlighted that the oximetry value of the main limb is not influenced by age, knowledge of the main limb, years of general and gymnastic sports activity (p > 0.05). We discovered an increase of Achilles tendon perfusion in the main limb in the artistic gymnast group. We hypothesize that specific figures of artistic sports activity are responsible for muscle overload and gastrocnemius-soleus group and, at the same time, these figures cause hyperperfusion of the tendon. Prospective longitudinal studies could explain if this could become a predictive sign of the next Achilles tendinopathy onset.

  17. Influence of long-term wearing of unstable shoes on compensatory control of posture: an electromyography-based analysis.

    Science.gov (United States)

    Sousa, Andreia S P; Silva, Andreia; Macedo, Rui; Santos, Rubim; Tavares, João Manuel R S

    2014-01-01

    This study investigated the influence of long-term wearing of unstable shoes (WUS) on compensatory postural adjustments (CPA) to an external perturbation. Participants were divided into two groups: one wore unstable shoes while the other wore conventional shoes for 8 weeks. The ground reaction force signal was used to calculate the anterior-posterior (AP) displacement of the centre of pressure (CoP) and the electromyographic signal of gastrocnemius medialis (GM), tibialis anterior (TA), rectus femoris (RF) and biceps femoris (BF) muscles was used to assess individual muscle activity, antagonist co-activation and reciprocal activation at the joint (TA/GM and RF/(BF+GM) pairs) and muscle group levels (ventral (TA+RF)/dorsal (GM+BF) pair) within time intervals typical for CPA. The electromyographic signal was also used to assess muscle latency. The variables described were evaluated before and after the 8-week period while wearing the unstable shoes and barefoot. Long-term WUS led to: an increase of BF activity in both conditions (barefoot and wearing the unstable shoes); a decrease of GM activity; an increase of antagonist co-activation and a decrease of reciprocal activation level at the TA/GM and ventral/dorsal pairs in the unstable shoe condition. Additionally, WUS led to a decrease in CoP displacement. However, no differences were observed in muscle onset and offset. Results suggest that the prolonged use of unstable shoes leads to increased ankle and muscle groups' antagonist co-activation levels and higher performance by the postural control system. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Radiation control

    International Nuclear Information System (INIS)

    Uchida, Akira

    1981-01-01

    This paper describes on how the condition of radiation level in the ring (storage ring) experimentation room changes corresponding to the operating stage of SOR-ring (synchrotron radiation storage ring), and does not describe on the present radiation control in the SOR facility. The operating stage of SOR is divided into the following five: (1) 307 MeV electron injection, (2) 307 MeV electron storage (used for SOR experiments), (3) energy increase from 307 to 380 MeV, (4) 380 MeV electron storage, (5) re-injection and completion of operation. Gamma and X ray levels are shown when electron beam is injected from the electron synchrotron to the SOR-ring. Two main causes of the high level are reported. Spatial dose rate in storing 307 MeV electrons in also illustrated. This is sufficiently lower than that at electron incidence. The measurement of radiation level at the time of energy increase from 307 to 380 MeV has just started. Since the radiation level in 380 MeV storage, measured at the points about 20 cm apart from the electron orbit, showed several mR/h, the level seems to be negligible at the points where experiments are carried out, 1 m away from the measurement points. The radiation level in electron reinjection and completion of operation may be large during a short period (a few Roentgen) like the time of energy increase. Therefore, the beam shall be re-injected or decreased after confirming that all experimenters have retreated into the predetermined place. (Wakatsuki, Y.)

  19. Non-neural Muscle Weakness Has Limited Influence on Complexity of Motor Control during Gait

    Directory of Open Access Journals (Sweden)

    Marije Goudriaan

    2018-01-01

    Full Text Available Cerebral palsy (CP and Duchenne muscular dystrophy (DMD are neuromuscular disorders characterized by muscle weakness. Weakness in CP has neural and non-neural components, whereas in DMD, weakness can be considered as a predominantly non-neural problem. Despite the different underlying causes, weakness is a constraint for the central nervous system when controlling gait. CP demonstrates decreased complexity of motor control during gait from muscle synergy analysis, which is reflected by a higher total variance accounted for by one synergy (tVAF1. However, it remains unclear if weakness directly contributes to higher tVAF1 in CP, or whether altered tVAF1 reflects mainly neural impairments. If muscle weakness directly contributes to higher tVAF1, then tVAF1 should also be increased in DMD. To examine the etiology of increased tVAF1, muscle activity data of gluteus medius, rectus femoris, medial hamstrings, medial gastrocnemius, and tibialis anterior were measured at self-selected walking speed, and strength data from knee extensors, knee flexors, dorsiflexors and plantar flexors, were analyzed in 15 children with CP [median (IQR age: 8.9 (2.2], 15 boys with DMD [8.7 (3.1], and 15 typical developing (TD children [8.6 (2.7]. We computed tVAF1 from 10 concatenated steps with non-negative matrix factorization, and compared tVAF1 between the three groups with a Mann-Whiney U-test. Spearman's rank correlation coefficients were used to determine if weakness in specific muscle groups contributed to altered tVAF1. No significant differences in tVAF1 were found between DMD [tVAF1: 0.60 (0.07] and TD children [0.65 (0.07], while tVAF1 was significantly higher in CP [(0.74 (0.09] than in the other groups (both p < 0.005. In CP, weakness in the plantar flexors was related to higher tVAF1 (r = −0.72. In DMD, knee extensor weakness related to increased tVAF1 (r = −0.50. These results suggest that the non-neural weakness in DMD had limited influence on

  20. Control without Controllers: Toward a Distributed Neuroscience of Executive Control.

    Science.gov (United States)

    Eisenreich, Benjamin R; Akaishi, Rei; Hayden, Benjamin Y

    2017-10-01

    Executive control refers to the regulation of cognition and behavior by mental processes and is a hallmark of higher cognition. Most approaches to understanding its mechanisms begin with the assumption that our brains have anatomically segregated and functionally specialized control modules. The modular approach is intuitive: Control is conceptually distinct from basic mental processing, so an organization that reifies that distinction makes sense. An alternative approach sees executive control as self-organizing principles of a distributed organization. In distributed systems, control and controlled processes are colocalized within large numbers of dispersed computational agents. Control then is often an emergent consequence of simple rules governing the interaction between agents. Because these systems are unfamiliar and unintuitive, here we review several well-understood examples of distributed control systems, group living insects and social animals, and emphasize their parallels with neural systems. We then reexamine the cognitive neuroscience literature on executive control for evidence that its neural control systems may be distributed.

  1. Active vibration control by robust control techniques

    International Nuclear Information System (INIS)

    Lohar, F.A.

    2001-01-01

    This paper studies active vibration control of multi-degree-of-freedom system. The control techniques considered are LTR, H/sup 2/ and H/sup infinite/. The results show that LTR controls the vibration but its respective settling time is higher than that of the other techniques. The control performance of H/sup infinite/ control is similar to that of H/sup 2/ control in the case of it weighting functions. However, H/sup infinite/ control is superior to H/sup 2/ control with respect to robustness, steady state error and settling time. (author)

  2. Quantitation of progressive muscle fatigue during dynamic leg exercise in humans

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1995-01-01

    , a product of a contraction rate (1 Hz), force measured at the ankle, and distance of ankle movement from 90 degrees to 150 degrees of KE, was precisely controlled. Lack of rise in myoelectric activity in biceps femoris of the active leg during DKE and MVC was consistent with restriction of muscle action...

  3. Anthropometry. A Bibliography with Abstracts

    Science.gov (United States)

    1975-08-01

    population strengths with anthropometry matching that of astronauts. (Author) DESCRIPTORS: *Biodynamics, * Bionics # *Hand (anatomy), *Huscular...PTB sockets with a thermoplastic material; Human locomotion ; Multichannel myoelectric control—experimental report; Guidelines for standards tor...years of wheelchair evaluation; Some observations on the transverse rotations of the human trunk during locomotion ; Hydraulic knee controls for knee

  4. Electromyography physiology engineering and noninvasive applications

    CERN Document Server

    Parker, Philip; John Wiley & Sons

    2004-01-01

    "Featuring contributions from key innovators working in the field today, Electromyography reveals the broad applications of EMG data in areas as diverse as neurology, ergonomics, exercise physiology, rehabilitation, movement analysis, biofeedback, and myoelectric control of prostheses." "Electromyography offers physiologists, medical professionals, and students in biomedical engineering a new window into the possibilities of this technology."--Jacket.

  5. Bouncing on Mars and the Moon-the role of gravity on neuromuscular control: correlation of muscle activity and rate of force development.

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Krause, Anne; Gollhofer, Albert

    2016-11-01

    On our astronomical neighbors Mars and the Moon, bouncing movements are the preferred locomotor techniques. During bouncing, the stretch-shortening cycle describes the muscular activation pattern. This study aimed to identify gravity-dependent changes in kinematic and neuromuscular characteristics in the stretch-shortening cycle. Hence, neuromuscular control of limb muscles as well as correlations between the muscles' pre-activation, reflex components, and force output were assessed in lunar, Martian, and Earth gravity. During parabolic flights, peak force (F max ), ground-contact-time, rate of force development (RFD), height, and impulse were measured. Electromyographic (EMG) activities in the m. soleus (SOL) and gastrocnemius medialis (GM) were assessed before (PRE) and during bounces for the reflex phases short-, medium-, and long-latency response (SLR, MLR, LLR). With gradually decreasing gravitation, F max , RFD, and impulse were reduced, whereas ground-contact time and height increased. Concomitantly, EMG_GM decreased for PRE, SLR, MLR, and LLR, and in EMG_SOL in SLR, MLR, and LLR. For SLR and MLR, F max and RFD were positively correlated to EMG_SOL. For PRE and LLR, RFD and F max were positively correlated to EMG_GM. Findings emphasize that biomechanically relevant kinematic adaptations in response to gravity variation were accompanied by muscle- and phase-specific modulations in neural control. Gravitational variation is anticipated and compensated for by gravity-adjusted muscle activities. Importantly, the pre-activation and reflex phases were differently affected: in SLR and MLR, SOL is assumed to contribute to the decline in force output with a decreasing load, and, complementary in PRE and LLR, GM seems to be of major importance for force generation. Copyright © 2016 the American Physiological Society.

  6. Control panel for CMC 8080 crate controller

    International Nuclear Information System (INIS)

    Masayuki Inokuchi

    1978-01-01

    The main features of Control Panel for CAMAC Crate Controller CMC 8080 are described. The control panel can be directly connected with CRATE CONTROLLER's front panel connector with a 50 lines cable without any changes in CMC 8080 system circuits. (author)

  7. Hierarchical Control of Thermostatically Controller Loads for Primary Frequency Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Huang, Shaojun

    2016-01-01

    This paper proposes a hierarchical control of Thermostatically Controlled Loads (TCLs) to provide primary frequency control support. The control architecture is comprised of three levels. At the high level, an aggregator coordinates multiple distribution substations and dispatches the primary...... reserve references. At the middle level, distribution substations estimate the available power of TCLs based on the aggregated bin model, and dispatch control signals to individual TCLs. At the local level, a supplementary frequency control loop is implemented at the local controller, which makes TCLs...... respond to the frequency event autonomously. Case studies show that the proposed controller can efficiently respond to frequency events and fulfill the requirement specified by the system operator. The users’ comforts are not compromised and the short cycling of TCLs is largely reduced. Due...

  8. Performance of electromyography recorded using textile electrodes in classifying arm movements.

    Science.gov (United States)

    Li, Guanglin; Geng, Yanjuan; Tao, Dandan; Zhou, Ping

    2011-01-01

    Electromyography (EMG) signals are commonly recorded using the Ag/AgCl gel electrodes in myoelectric prosthetic control. While a gelled electrode may provide high-quality EMG recordings, it is inconvenient in clinical application of a myoelectric prosthesis. A novel type of signal sensors-textile electrodes should be ideal in control of myoelectric prostheses. However, it is unknown whether the performance of textile electrodes is comparable to commonly used electrodes in classifying arm movements. In this study, the custom-made bipolar textile electrodes were fabricated using copper-based nickel-plated conductive fabric and were used to record EMG signals. The performance of EMG signals recorded with textile electrodes in identifying nine arm and hand movements were investigated. Our pilot results showed that the average classification accuracy across six able-bodied subjects was 94.05% when using textile electrodes and 94.26% when using conventional electrodes, with no significant difference between the two types of electrodes (p=0.81). The pilot results suggest that the textile electrodes could achieve similar performance in classifying arm movements in control of myoelectric prostheses as the gelled metal electrodes.

  9. An intelligent traffic controller

    Science.gov (United States)

    1995-11-01

    Advances in computing sciences have not been applied to traffic control. This paper describes the development of an intelligent controller. A controller with advanced control logic can significantly improve traffic flows at intersections. In this vei...

  10. Incoherent control of locally controllable quantum systems

    International Nuclear Information System (INIS)

    Dong Daoyi; Zhang Chenbin; Rabitz, Herschel; Pechen, Alexander; Tarn, T.-J.

    2008-01-01

    An incoherent control scheme for state control of locally controllable quantum systems is proposed. This scheme includes three steps: (1) amplitude amplification of the initial state by a suitable unitary transformation, (2) projective measurement of the amplified state, and (3) final optimization by a unitary controlled transformation. The first step increases the amplitudes of some desired eigenstates and the corresponding probability of observing these eigenstates, the second step projects, with high probability, the amplified state into a desired eigenstate, and the last step steers this eigenstate into the target state. Within this scheme, two control algorithms are presented for two classes of quantum systems. As an example, the incoherent control scheme is applied to the control of a hydrogen atom by an external field. The results support the suggestion that projective measurements can serve as an effective control and local controllability information can be used to design control laws for quantum systems. Thus, this scheme establishes a subtle connection between control design and controllability analysis of quantum systems and provides an effective engineering approach in controlling quantum systems with partial controllability information.

  11. Contact Control, Version 1

    Energy Technology Data Exchange (ETDEWEB)

    2016-07-21

    The contact control code is a generalized force control scheme meant to interface with a robotic arm being controlled using the Robot Operating System (ROS). The code allows the user to specify a control scheme for each control dimension in a way that many different control task controllers could be built from the same generalized controller. The input to the code includes maximum velocity, maximum force, maximum displacement, and a control law assigned to each direction and the output is a 6 degree of freedom velocity command that is sent to the robot controller.

  12. Control Augmentation Using Fuzzy Logic Control

    Science.gov (United States)

    Kato, Akio; Inukai, Daisuke

    Overall control to improve the control characteristics of an aircraft, CA (Control Augmentation), is used to realize the desirable motion of the aircraft in relation to the pilot’s control action. C∗ criterion is an important factor for the pilot’s preferred longitudinal motion. The time history of C∗ corresponding to the step input is specified within the upper and lower envelope, and it is desirable to be near the center of the envelope. In this research, the control laws of control augmentation for small supersonic aircraft were designed with the use of fuzzy logic control to obtain the C∗ response near the center of the envelope. The evaluation of the designed control laws showed good performance in all flight conditions. Here the control laws were varied by only one scaling factor for dynamic pressure. This means that virtually no gain schedules by the Mach number and the angle of attack are necessary. This paper shows that fuzzy logic control is an effective and flexible method when applied to control laws for the control augmentation of aircraft.

  13. Personal exposure control system

    International Nuclear Information System (INIS)

    Tanabe, Ken-ichi; Akashi, Michio

    1994-01-01

    Nuclear power stations are under strict radiation control. Exposure control for nuclear workers is the most important operation, and so carefully thought out measures are taken. This paper introduces Fuji Electric's personal exposure control system that meets strict exposure control and rationalizes control operations. The system has a merit that it can provide required information in an optimum form using the interconnection of a super minicomputer and exposure control facilities and realizes sophisticated exposure control operations. (author)

  14. Effects of TRPV1 and TRPA1 activators on the cramp threshold frequency: a randomized, double-blind placebo-controlled trial.

    Science.gov (United States)

    Behringer, Michael; Nowak, Stephanie; Leyendecker, Jannik; Mester, Joachim

    2017-08-01

    Previous data indicate that a strong sensory input from orally administered TRPV1 and TRPA1 activators alleviates muscle cramps in foot muscles by reducing the α-motor neuron hyperexcitability. We investigated if TRP activators increase the cramp threshold frequency of the medial gastrocnemius. We randomly assigned 22 healthy male participants to an intervention (IG) and a control group (CG). While participants of the IG ingested a mixture of TRPV1 and TRPA1 activators, the CG received a placebo. We tested the cramp threshold frequency (CTF), the cramp intensity (EMG activity), and the perceived pain of electrically induced muscle cramps before (pre), and 15 min, 4, 8, and 24 h after either treatment. We further measured the maximal isometric force of knee extensors at pre, 4, and 24 h to assess potential side-effects on the force output. When we included all measurement time points, no group-by-time interaction was observed for the CTF. However, when only pre and 15 min values were incorporated, a significant interaction, with a slightly greater CTF increase in IG (3.1 ± 1.5) compared to the CG (2.0 ± 1.5), was observed. No significant group by time interaction was found for the cramp intensity, the perceived pain, and the maximal isometric force. Our data indicate that orally administered TRPV1 and TRPA1 activators exert a small short-term effect on the CTF, but not on the other parameters tested. Future studies need to investigate whether such small CTF increments are sufficient to prevent exercise-associated muscle cramps.

  15. Modulation of GLUT4 expression by oral administration of Mg(2+) to control sugar levels in STZ-induced diabetic rats.

    Science.gov (United States)

    Solaimani, Haniah; Soltani, Nepton; MaleKzadeh, Kianoosh; Sohrabipour, Shahla; Zhang, Nina; Nasri, Sema; Wang, Qinghua

    2014-06-01

    It has been previously shown that oral magnesium administration decreases the levels of glucose in the plasma. However, the mechanisms are not fully understood. The aim of this study was to determine the potential role of GLUT4 on plasma glucose levels by orally administering magnesium sulfate to diabetic rats. Animals were distributed among 4 groups (n = 10 rats per group): one group served as the non-diabetic control, while the other groups had diabetes induced by streptozotocin (intraperitoneal (i.p.) injection). The diabetic rats were either given insulin by i.p. injection (2.5 U·(kg body mass)(-1)·day(-1)), or magnesium sulfate in their drinking water (10 g·L(-1)). After 8 weeks of treatment, we conducted an i.p. glucose tolerance test (IPGTT), measured blood glucose and plasma magnesium levels, and performed in-vitro and in-vivo insulin level measurements by radioimmunoassay. Gastrocnemius (leg) muscles were isolated for the measurement of GLU4 mRNA expression using real-time PCR. Administration of magnesium sulfate improved IPGTT and lowered blood glucose levels almost to the normal range. However, the insulin levels were not changed in either of the in-vitro or in-vivo studies. The expression of GLU4 mRNA increased 23% and 10% in diabetic magnesium-treated and insulin-treated groups, respectively. Our findings suggest that magnesium lowers blood glucose levels via increased GLU4 mRNA expression, independent to insulin secretion.

  16. Day vs. day-night use of ankle-foot orthoses in young children with spastic diplegia: a randomized controlled study.

    Science.gov (United States)

    Zhao, Xiaoke; Xiao, Nong; Li, Hongying; Du, Senjie

    2013-10-01

    The aim of this study was to compare the effectiveness of treatment with hinged ankle-foot orthoses (AFOs) during the day vs. during both the day and the night in young ambulant children with spastic diplegia. In this prospective randomized controlled trial, 112 ambulatory children (70 boys and 42 girls; mean age, 2 yrs 6.93 mos; range, 1 yr 1 mo to 4 yrs 0 mo) with spastic diplegia participated. Forty-eight were classified at level I of the Gross Motor Function Classification System; the remaining 64 were at level II. Using stratified randomization, all children were assigned to either the day AFO-wearing group (n = 56, wearing AFOs all day) or the day-night AFO-wearing group (n = 56, wearing AFOs all day and all night). The two groups underwent conventional rehabilitative treatments five times a week for 8 wks. The primary outcomes measured were passive ankle dorsiflexion angle and sections D and E of the 66-item Gross Motor Function Measure; the root mean square of surface electromyography in the ventral and dorsal lower limb muscles was compared in a subgroup (ten from each group). Seven children did not complete the full intervention: three in the day AFO-wearing group and four in the day-night AFO-wearing group. Significant baseline-postintervention improvements were found for passive ankle dorsiflexion angle and the 66-item Gross Motor Function Measure in both groups (P AFO-wearing group (P AFO-wearing group, whereas the muscles affected in the day-night AFO-wearing group were the gastrocnemius (P AFOs was more effective in improving Gross Motor Function Measure scores than the day-night use. In addition, the prolonged wearing of AFOs may influence muscle activity, which should be monitored in the clinic.

  17. PID control with robust disturbance feedback control

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Vinther, Kasper; Andersen, Palle

    2015-01-01

    Disturbance Feedback Control (DFC) is a technique, originally proposed by Fuji Electric, for augmenting existing control systems with an extra feedback for attenuation of disturbances and model errors. In this work, we analyze the robustness and performance of a PID-based control system with DFC...... and performance (if such gains exist). Finally, two different simulation case studies are evaluated and compared. Our numerical studies indicate that better performance can be achieved with the proposed method compared with a conservatively tuned PID controller and comparable performance can be achieved when...... compared with an H-infinity controller....

  18. Superconducting fault current controller/current controller

    Science.gov (United States)

    Cha, Yung S.

    2004-06-15

    A superconducting fault current controller/current controller employs a superconducting-shielded core reactor (SSCR) with a variable impedance in a secondary circuit to control current in a primary circuit such as an electrical distribution system. In a second embodiment, a variable current source is employed in a secondary circuit of an SSCR to control current in the primary circuit. In a third embodiment, both a variable impedance in one secondary circuit and a variable current source in a second circuit of an SSCR are employed for separate and independent control of current in the primary circuit.

  19. Solid state controller three axes controller

    Science.gov (United States)

    Bailey, C. L., Jr. (Inventor)

    1973-01-01

    The reported flight controller features a handle grip which is mounted on a longitudinally extending control element. The handle grip is pivotally mounted on the control element about a pitch axis which is perpendicular to the longitudinal axis through the control element. The pivotal mounting includes a resilient force mounting mechanism which centers the grip relative to the control element. Rotation of the handle grip produces a direct rotation of a transducer element in a transducer which provides an electrical indication of the rotative movement about three mutually perpendicular axes.

  20. Adaptive Extremum Control and Wind Turbine Control

    DEFF Research Database (Denmark)

    Ma, Xin

    1997-01-01

    This thesis is divided into two parts, i.e., adaptive extremum control and modelling and control of a wind turbine. The rst part of the thesis deals with the design of adaptive extremum controllers for some processes which have the behaviour that process should have as high e ciency as possible...... in parameters, and thus directly lends itself to parameter estimation and adaptive control. The extremum control law is derived based on static optimization of a performance function. For a process with nonlinearity at output the intermediate signal between the linear part and nonlinear part plays an important...... role. If it can be emphasis on control design. The models have beenvalidated by experimental data obtained from an existing wind turbine. The e ective wind speed experienced by the rotor of a wind turbine, which is often required by some control methods, is estimated by using a wind turbine as a wind...