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Sample records for leg extension force

  1. Effective force application in guided leg extensions

    NARCIS (Netherlands)

    Doorenbosch, C.A.M.; Veeger, H. E J; van Zandwijk, J. P.; van Ingen Schenau, G. J.

    1996-01-01

    In guided movements, limb kinematics is determined by the object on which a force is applied (as in cycling). Consequently, the force direction may deviate from the effective direction. It is examined how effective force application is related to maximal power output. A recent study, where subjects

  2. Muscle strategies for leg extensions on a "Reformer" apparatus.

    Science.gov (United States)

    Cantergi, Débora; Loss, Jefferson Fagundes; Jinha, Azim; Brodt, Guilherme Auler; Herzog, Walter

    2015-04-01

    Considering the kinematics of leg extensions performed on a Reformer apparatus, one would expect high activation of hip and knee extensor muscle groups. However, because of the bi-articular nature of some lower limb muscles, and the possibility to vary the direction of force application on the Reformer bar, muscles can be coordinated theoretically in a variety of ways and still achieve the desired outcome. Hence, the aim of this study was to determine the knee and hip moments during leg extensions performed on the Reformer apparatus and to estimate the forces in individual muscles crossing these joints using static optimization. Fifteen subjects performed leg extensions exercises on the Reformer apparatus using an individually chosen resistance. To our big surprise, we found that subjects performed the exercise using two conceptually different strategies (i) the first group used simultaneous hip and knee extension moments, (ii) while the second group used simultaneous hip flexion and knee extension moments to perform the exercise. These different strategies were achieved by changing the direction of the resultant force applied by the subject's feet on the Reformer bar. While leg extensions on the Reformer apparatus have been thought to strengthen the hip and knee extensors muscles, our results demonstrate that patients can perform the exercise in a different and unexpected way. In order to control the hip and knee moments and achieve the desired outcome of the exercise, the direction of force application on the Reformer bar must be controlled carefully. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Muscle recruitment patterns during the prone leg extension

    Directory of Open Access Journals (Sweden)

    Rayfield Ben

    2004-02-01

    Full Text Available Abstract Background The prone leg extension (PLE is a clinical test used to evaluate the function of the lumbopelvis. It has been theorized that a normal and consistent pattern of muscle activation exists. Previous research has found two contradictory patterns of muscle activation during PLE in normal individuals. One study shows an almost simultaneous activation of the lower erector spinae and hamstring muscle group with a delayed activation of the gluteus maximus, while the second describes the order of activation being ipsilateral erector spinae (to the leg being extended, hamstrings, contralateral erector spinae and gluteus maximus. Due to the different conclusions from these two studies and the lack of quantified muscle onset times, expressed in absolute time this study attempted to quantify the muscle onset times (in milliseconds during the prone leg extension, while noting if a consistent order of activation exists and whether a timing relationship also exists between the gluteus maximus and contralateral latissimus dorsi. Methods 10 asymptomatic males (Average height: 175.2 cm (SD 6.5, Average Weight 75.9 kg (SD 6.5, Average Age: 27.1(SD 1.28 and 4 asymptomatic females (Average height 164.5 (SD 2.9, weight: 56.2 (SD 8.9, Average Age: 25 (SD 1 performed the prone leg extension task while the myoelectric signal was recorded from the bilateral lower erector spinae, gluteus maximus and hamstring muscle groups. Activation onsets were determined from the rectified EMG signal relative to the onset of the hamstrings muscle group. Results No consistent recruitment patterns were detected for prone leg extension among the hamstring muscle group and the erector spinae. However, a consistent delay in the Gluteus Maximus firing of approximately 370 ms after the first muscle activated was found. Five out of 14 asymptomatic subjects showed a delay in gluteus maximus firing exceeding the average delay found in previous research of subjects considered to

  4. Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension.

    Science.gov (United States)

    Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar

    2014-08-01

    Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated single-joint movements. Thus, the purpose of this study was to determine force/torque-angle and force/torque-angular velocity properties for multi-joint leg extensions. Human leg extension was investigated (n = 18) on a motor-driven leg press dynamometer while measuring external reaction forces at the feet. Extensor torque in the knee joint was calculated using inverse dynamics. Isometric contractions were performed at eight joint angle configurations of the lower limb corresponding to increments of 10° at the knee from 30 to 100° of knee flexion. Concentric and eccentric contractions were performed over the same range of motion at mean angular velocities of the knee from 30 to 240° s(-1). For contractions of increasing velocity, optimum knee angle shifted from 52 ± 7 to 64 ± 4° knee flexion. Furthermore, the curvature of the concentric force/torque-angular velocity relations varied with joint angles and maximum angular velocities increased from 866 ± 79 to 1,238 ± 132° s(-1) for 90-50° knee flexion. Normalised eccentric forces/torques ranged from 0.85 ± 0.12 to 1.32 ± 0.16 of their isometric reference, only showing significant increases above isometric and an effect of angular velocity for joint angles greater than optimum knee angle. The findings reveal that force/torque production during multi-joint leg extension depends on the combined effects of angle and angular velocity. This finding should be accounted for in modelling and optimisation of human movement.

  5. Radial deformations of working cylinder of hydraulic Legs depending on their extension

    OpenAIRE

    Buyalich, Gennadiy Daniilovich; Buyalich, K. G.; Voyevodin, V. V.

    2015-01-01

    Current methods of calculation of parameters of hydraulic legs of powered supports are in most cases analytical and do not consider all complex of factors. Finite element model was developed to study this problem and used to analyze the influence of hydraulic legs extension on radial deformations of cylinder of different producers of powered supports at variation of hydraulic fluid pressure. It was revealed that radial deformations of cylinders along the axis of hydraulic legs increase in mag...

  6. Forced Use of the Paretic Leg Induced by a Constraint Force Applied to the Nonparetic Leg in Individuals Poststroke During Walking.

    Science.gov (United States)

    Hsu, Chao-Jung; Kim, Janis; Roth, Elliot J; Rymer, William Z; Wu, Ming

    2017-12-01

    Individuals with stroke usually show reduced muscle activities of the paretic leg and asymmetrical gait pattern during walking. To determine whether applying a resistance force to the nonparetic leg would enhance the muscle activities of the paretic leg and improve the symmetry of spatiotemporal gait parameters in individuals with poststroke hemiparesis. Fifteen individuals with chronic poststroke hemiparesis participated in this study. A controlled resistance force was applied to the nonparetic leg using a customized cable-driven robotic system while subjects walked on a treadmill. Subjects completed 2 test sections with the resistance force applied at different phases of gait (ie, early and late swing phases) and different magnitudes (10%, 20%, and 30% of maximum voluntary contraction [MVC] of nonparetic leg hip flexors). Electromyographic (EMG) activity of the muscles of the paretic leg and spatiotemporal gait parameters were collected. Significant increases in integrated EMG of medial gastrocnemius, medial hamstrings, vastus medialis, and tibialis anterior of the paretic leg were observed when the resistance was applied during the early swing phase of the nonparetic leg, compared with baseline. Additionally, resistance with 30% of MVC induced the greatest level of muscle activity than that with 10% or 20% of MVC. The symmetry index of gait parameters also improved with resistance applied during the early swing phase. Applying a controlled resistance force to the nonparetic leg during early swing phase may induce forced use on the paretic leg and improve the spatiotemporal symmetry of gait in individuals with poststroke hemiparesis.

  7. Differential glucose uptake in quadriceps and other leg muscles during one-legged dynamic submaximal knee-extension exercise

    DEFF Research Database (Denmark)

    Kalliokoski, Kari K; Boushel, Robert; Langberg, Henning

    2011-01-01

    to mean GU in QF (=100%), GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between......One-legged dynamic knee-extension exercise (DKE) is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron...... in the vastus intermedius (VI) and lowest in the vastus lateralis (VL; VI vs VL, p muscles in the exercising leg was 35 ± 9%. Compared...

  8. Differential glucose uptake in quadriceps and other leg muscles during one-legged dynamic submaximal knee-extension exercise

    Directory of Open Access Journals (Sweden)

    Kari eKalliokoski

    2011-10-01

    Full Text Available One-legged dynamic knee-extension exercise (DKE is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron emission tomography (PET determined uptake of [18F]-fluoro-deoxy-glucose (GU during DKE. Five healthy male subjects performed DKE at 25 W for 35 min and both the contracting and contralateral resting leg were scanned with PET from mid-thigh and distally. On average, exercise GU was the highest in the vastus intermedius (VI and lowest in the vastus lateralis (VL (VI vs VL, p<0.05, whereas the coefficient of variation was highest in VL (VL vs VI, p<0.05. Coefficient of variation between the mean values of the four QF muscles in the exercising leg was 35±9%. Compared to mean GU in QF (=100%, GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between individuals vary greatly during DKE, and suggests that muscle activity is not equal between quadriceps muscles in this exercise model. Furthermore, posterior thigh muscles and lower leg muscles are more active than hitherto thought even during this moderate exercise intensity.

  9. Force balance in the take-off of a pierid butterfly: relative importance and timing of leg impulsion and aerodynamic forces.

    Science.gov (United States)

    Bimbard, Gaëlle; Kolomenskiy, Dmitry; Bouteleux, Olivier; Casas, Jérôme; Godoy-Diana, Ramiro

    2013-09-15

    Up to now, the take-off stage has remained an elusive phase of insect flight that was relatively poorly explored compared with other maneuvers. An overall assessment of the different mechanisms involved in force production during take-off has never been explored. Focusing on the first downstroke, we have addressed this problem from a force balance perspective in butterflies taking off from the ground. In order to determine whether the sole aerodynamic wing force could explain the observed motion of the insect, we have firstly compared a simple analytical model of the wing force with the acceleration of the insect's center of mass estimated from video tracking of the wing and body motions. Secondly, wing kinematics were also used for numerical simulations of the aerodynamic flow field. Similar wing aerodynamic forces were obtained by the two methods. However, neither are sufficient, nor is the inclusion of the ground effect, to predict faithfully the body acceleration. We have to resort to the leg forces to obtain a model that best fits the data. We show that the median and hind legs display an active extension responsible for the initiation of the upward motion of the insect's body, occurring before the onset of the wing downstroke. We estimate that legs generate, at various times, an upward force that can be much larger than all other forces applied to the insect's body. The relative timing of leg and wing forces explains the large variability of trajectories observed during the maneuvers.

  10. Definable maximal discrete sets in forcing extensions

    DEFF Research Database (Denmark)

    Törnquist, Asger Dag; Schrittesser, David

    2018-01-01

    Let  be a Σ11 binary relation, and recall that a set A is -discrete if no two elements of A are related by . We show that in the Sacks and Miller forcing extensions of L there is a Δ12 maximal -discrete set. We use this to answer in the negative the main question posed in [5] by showing...

  11. Applying a pelvic corrective force induces forced use of the paretic leg and improves paretic leg EMG activities of individuals post-stroke during treadmill walking.

    Science.gov (United States)

    Hsu, Chao-Jung; Kim, Janis; Tang, Rongnian; Roth, Elliot J; Rymer, William Z; Wu, Ming

    2017-10-01

    To determine whether applying a mediolateral corrective force to the pelvis during treadmill walking would enhance muscle activity of the paretic leg and improve gait symmetry in individuals with post-stroke hemiparesis. Fifteen subjects with post-stroke hemiparesis participated in this study. A customized cable-driven robotic system based over a treadmill generated a mediolateral corrective force to the pelvis toward the paretic side during early stance phase. Three different amounts of corrective force were applied. Electromyographic (EMG) activity of the paretic leg, spatiotemporal gait parameters and pelvis lateral displacement were collected. Significant increases in integrated EMG of hip abductor, medial hamstrings, soleus, rectus femoris, vastus medialis and tibialis anterior were observed when pelvic corrective force was applied, with pelvic corrective force at 9% of body weight inducing greater muscle activity than 3% or 6% of body weight. Pelvis lateral displacement was more symmetric with pelvic corrective force at 9% of body weight. Applying a mediolateral pelvic corrective force toward the paretic side may enhance muscle activity of the paretic leg and improve pelvis displacement symmetry in individuals post-stroke. Forceful weight shift to the paretic side could potentially force additional use of the paretic leg and improve the walking pattern. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  12. Stride Leg Ground Reaction Forces Predict Throwing Velocity in Adult Recreational Baseball Pitchers.

    Science.gov (United States)

    McNally, Michael P; Borstad, John D; Oñate, James A; Chaudhari, Ajit M W

    2015-10-01

    Ground reaction forces produced during baseball pitching have a significant impact in the development of ball velocity. However, the measurement of only one leg and small sample sizes in these studies curb the understanding of ground reaction forces as they relate to pitching. This study aimed to further clarify the role ground reaction forces play in developing pitching velocity. Eighteen former competitive baseball players with previous high school or collegiate pitching experience threw 15 fastballs from a pitcher's mound instrumented to measure ground reaction forces under both the drive and stride legs. Peak ground reaction forces were recorded during each phase of the pitching cycle, between peak knee height and ball release, in the medial/lateral, anterior/posterior, and vertical directions, and the peak resultant ground reaction force. Stride leg ground reaction forces during the arm-cocking and arm-acceleration phases were strongly correlated with ball velocity (r2 = 0.45-0.61), whereas drive leg ground reaction forces showed no significant correlations. Stepwise linear regression analysis found that peak stride leg ground reaction force during the arm-cocking phase was the best predictor of ball velocity (r2 = 0.61) among drive and stride leg ground reaction forces. This study demonstrates the importance of ground reaction force development in pitching, with stride leg forces being strongly predictive of ball velocity. Further research is needed to further clarify the role of ground reaction forces in pitching and to develop training programs designed to improve upper extremity mechanics and pitching performance through effective force development.

  13. Proper Posture of Redundant Legged Biped Robot for Impact Force Suppression

    Science.gov (United States)

    Tasaki, Go; Shibata, Masaaki

    The paper describes proper initial posture of the swinging leg of a redundant legged biped robot for impact force suppression in landing onto the ground. The proposed robot has structural advantage for absorbing the impact because of its own redundancy of posture, and then, the proper posture of the landing leg contributes the further suppression. The validity of the proposed approach is confirmed in physical experimental results.

  14. Chronic ulceration of the leg following extensive scarring due to a snake bite complicated by squamous cell carcinoma

    International Nuclear Information System (INIS)

    Mello, L.F.B.; Barcelos, M.G.; Nogueira Neto, N.C.; Meohas, W.; Pinto, L.W.; Melo, P.A.; Smith, J.

    2000-01-01

    Chronic ulcers of the leg are common in Brazil, perhaps more common than in the developed world. We report a case of a chronic ulcer of the leg following extensive scarring due to a bite by a venomous snake, which eventually led to a squamous cell carcinoma. (orig.)

  15. Impact Force Suppression for Redundant Legged Biped Robot Based on Unified Decoupling Control Method

    Science.gov (United States)

    Shibata, Masaaki; Tasaki, Go; Natori, Takeshi

    A swinging leg of a biped robot landing, impact force usually occurs between the sole and the ground, and then it causes instability of the gait. The paper describes the advantages of adopting redundant legs to the robot in order to conquer the difficulty, and proposes a novel way of the motion control for the redundant legged biped robot. In general, each leg of a conventional biped robot consists of 3 joints, namely, hip, knee and ankle in the sagittal plane. On the other hand, the proposed robot has been added extra joints, and thereby has redundancy in terms of degrees-of-freedom. Since the redundant leg can select its arbitrary posture, regardless of the tip position, the structure enables to move the position of the center of mass (COM) of the leg independently. The impact force is suppressed by controlling the COM acceleration of the landing leg. In order to achieve the decoupled motions between the tip and the COM, the unified decoupling controller is introduced. The controller includes three types of the disturbance observers together, and both desired motions are realized consequently. The validity of the proposed approach is confirmed in physical experimental results.

  16. Dynamics and Optimal Feet Force Distributions of a Realistic Four-legged Robot

    Directory of Open Access Journals (Sweden)

    Saurav Agarwal

    2012-08-01

    Full Text Available This paper presents a detailed dynamic modeling of realistic four-legged robot. The direct and inverse kinematic analysis for each leg has been considered in order to develop an overall kinematic model of the robot, when it follows a straight path. This study also aims to estimate optimal feet force distributions of the said robot, which is necessary for its real-time control. Three different approaches namely, minimization of norm of feet forces (approach 1, minimization of norm of joint torques (approach 2 and minimization of norm of joint power (approach 3 have been developed. Simulation result shows that approach 3 is more energy efficient foot force formulation than other two approaches. Lagrange-Euler formulation has been utilized to determine the joint torques. The developed dynamic models have been examined through computer simulation of continuous gait of the four-legged robot.

  17. Prophylactic knee bracing alters lower-limb muscle forces during a double-leg drop landing.

    Science.gov (United States)

    Ewing, Katie A; Fernandez, Justin W; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

    2016-10-03

    Anterior cruciate ligament (ACL) injury can be a painful, debilitating and costly consequence of participating in sporting activities. Prophylactic knee bracing aims to reduce the number and severity of ACL injury, which commonly occurs during landing maneuvers and is more prevalent in female athletes, but a consensus on the effectiveness of prophylactic knee braces has not been established. The lower-limb muscles are believed to play an important role in stabilizing the knee joint. The purpose of this study was to investigate the changes in lower-limb muscle function with prophylactic knee bracing in male and female athletes during landing. Fifteen recreational athletes performed double-leg drop landing tasks from 0.30m and 0.60m with and without a prophylactic knee brace. Motion analysis data were used to create subject-specific musculoskeletal models in OpenSim. Static optimization was performed to calculate the lower-limb muscle forces. A linear mixed model determined that the hamstrings and vasti muscles produced significantly greater flexion and extension torques, respectively, and greater peak muscle forces with bracing. No differences in the timings of peak muscle forces were observed. These findings suggest that prophylactic knee bracing may help to provide stability to the knee joint by increasing the active stiffness of the hamstrings and vasti muscles later in the landing phase rather than by altering the timing of muscle forces. Further studies are necessary to quantify whether prophylactic knee bracing can reduce the load placed on the ACL during intense dynamic movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Novel Door-opening Method for Six-legged Robots Based on Only Force Sensing

    Science.gov (United States)

    Chen, Zhi-Jun; Gao, Feng; Pan, Yang

    2017-09-01

    Current door-opening methods are mainly developed on tracked, wheeled and biped robots by applying multi-DOF manipulators and vision systems. However, door-opening methods for six-legged robots are seldom studied, especially using 0-DOF tools to operate and only force sensing to detect. A novel door-opening method for six-legged robots is developed and implemented to the six-parallel-legged robot. The kinematic model of the six-parallel-legged robot is established and the model of measuring the positional relationship between the robot and the door is proposed. The measurement model is completely based on only force sensing. The real-time trajectory planning method and the control strategy are designed. The trajectory planning method allows the maximum angle between the sagittal axis of the robot body and the normal line of the door plane to be 45º. A 0-DOF tool mounted to the robot body is applied to operate. By integrating with the body, the tool has 6 DOFs and enough workspace to operate. The loose grasp achieved by the tool helps release the inner force in the tool. Experiments are carried out to validate the method. The results show that the method is effective and robust in opening doors wider than 1 m. This paper proposes a novel door-opening method for six-legged robots, which notably uses a 0-DOF tool and only force sensing to detect and open the door.

  19. 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.

  20. Wing and body motion and aerodynamic and leg forces during take-off in droneflies.

    Science.gov (United States)

    Chen, Mao Wei; Zhang, Yan Lai; Sun, Mao

    2013-12-06

    Here, we present a detailed analysis of the take-off mechanics in droneflies performing voluntary take-offs. Wing and body kinematics of the insects during take-off were measured using high-speed video techniques. Based on the measured data, the inertia force acting on the insect was computed and the aerodynamic force of the wings was calculated by the method of computational fluid dynamics. Subtracting the aerodynamic force and the weight from the inertia force gave the leg force. In take-off, a dronefly increases its stroke amplitude gradually in the first 10-14 wingbeats and becomes airborne at about the 12th wingbeat. The aerodynamic force increases monotonously from zero to a value a little larger than its weight, and the leg force decreases monotonously from a value equal to its weight to zero, showing that the droneflies do not jump and only use aerodynamic force of flapping wings to lift themselves into the air. Compared with take-offs in insects in previous studies, in which a very large force (5-10 times of the weight) generated either by jumping legs (locusts, milkweed bugs and fruit flies) or by the 'fling' mechanism of the wing pair (butterflies) is used in a short time, the take-off in the droneflies is relatively slow but smoother.

  1. Normalized knee-extension strength or leg-press power after fast-track total knee arthroplasty

    DEFF Research Database (Denmark)

    Aalund, Peter K; Larsen, Kristian; Hansen, Torben Bæk

    2013-01-01

    : Cross-sectional, exploratory study. SETTING: Laboratory at a regional hospital. PARTICIPANTS: Thirty-nine individuals with an average age of 65.5±10.3 yrs, who all had unilateral TKA 28 days prior. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The patients performed maximal isometric knee extensions......OBJECTIVE: (s): To investigate which of the two muscle-impairment measures for the operated leg, normalized knee extension strength or leg press power, is more closely associated to performance-based and self-reported measures of function shortly following total knee arthroplasty (TKA). DESIGN...... and dynamic leg presses to determine their body-mass normalized knee extension strength and leg press power, respectively. The 10-m fast speed walking and 30-s chair stand tests were used to determine performance-based function, while the Western Ontario McMaster University Osteoarthritis Index (WOMAC...

  2. Voluntary enhanced cocontraction of hamstring muscles during open kinetic chain leg extension exercise: its potential unloading effect on the anterior cruciate ligament.

    Science.gov (United States)

    Biscarini, Andrea; Benvenuti, Paolo; Botti, Fabio M; Brunetti, Antonella; Brunetti, Orazio; Pettorossi, Vito E

    2014-09-01

    A number of research studies provide evidence that hamstring cocontraction during open kinetic chain knee extension exercises enhances tibiofemoral (TF) stability and reduces the strain on the anterior cruciate ligament. To determine the possible increase in hamstring muscle coactivation caused by a voluntary cocontraction effort during open kinetic chain leg-extension exercises, and to assess whether an intentional hamstring cocontraction can completely suppress the anterior TF shear force during these exercises. Descriptive laboratory study. Knee kinematics as well as electromyographic activity in the semitendinosus (ST), semimembranosus (SM), biceps femoris (BF), and quadriceps femoris muscles were measured in 20 healthy men during isotonic leg extension exercises with resistance (R) ranging from 10% to 80% of the 1-repetition maximum (1RM). The same exercises were also performed while the participants attempted to enhance hamstring coactivation through a voluntary cocontraction effort. The data served as input parameters for a model to calculate the shear and compressive TF forces in leg extension exercises for any set of coactivation patterns of the different hamstring muscles. For R≤ 40% 1RM, the peak coactivation levels obtained with intentional cocontraction (l) were significantly higher (P hamstring muscle, maximum level l was reached at R = 30% 1RM, corresponding to 9.2%, 10.5%, and 24.5% maximum voluntary isometric contraction (MVIC) for the BF, ST, and SM, respectively, whereas the ratio l/l 0 reached its maximum at R = 20% 1RM and was approximately 2, 3, and 4 for the BF, SM, and ST, respectively. The voluntary enhanced coactivation level l obtained for R≤ 30% 1RM completely suppressed the anterior TF shear force developed by the quadriceps during the exercise. In leg extension exercises with resistance R≤ 40% 1RM, coactivation of the BF, SM, and ST can be significantly enhanced (up to 2, 3, and 4 times, respectively) by a voluntary hamstring

  3. Split-belt walking adaptation recalibrates sensorimotor estimates of leg speed but not position or force

    Science.gov (United States)

    Vazquez, Alejandro; Statton, Matthew A.; Busgang, Stefanie A.

    2015-01-01

    Motor learning during reaching not only recalibrates movement but can also lead to small but consistent changes in the sense of arm position. Studies have suggested that this sensory effect may be the result of recalibration of a forward model that associates motor commands with their sensory consequences. Here we investigated whether similar perceptual changes occur in the lower limbs after learning a new walking pattern on a split-belt treadmill—a task that critically involves proprioception. Specifically, we studied how this motor learning task affects perception of leg speed during walking, perception of leg position during standing or walking, and perception of contact force during stepping. Our results show that split-belt adaptation leads to robust motor aftereffects and alters the perception of leg speed during walking. This is specific to the direction of walking that was trained during adaptation (i.e., backward or forward). The change in leg speed perception accounts for roughly half of the observed motor aftereffect. In contrast, split-belt adaptation does not alter the perception of leg position during standing or walking and does not change the perception of stepping force. Our results demonstrate that there is a recalibration of a sensory percept specific to the domain of the perturbation that was applied during walking (i.e., speed but not position or force). Furthermore, the motor and sensory consequences of locomotor adaptation may be linked, suggesting overlapping mechanisms driving changes in the motor and sensory domains. PMID:26424576

  4. Lower Limb Force, Velocity, Power Capabilities during Leg Press and Squat Movements.

    Science.gov (United States)

    Padulo, Johnny; Migliaccio, Gian Mario; Ardigò, Luca Paolo; Leban, Bruno; Cosso, Marco; Samozino, Pierre

    2017-12-01

    The aim was to compare lower-limb power, force, and velocity capabilities between squat and leg press movements. Ten healthy sportsmen performed ballistic lower-limb push-offs against 5-to-12 different loads during both the squat and leg press. Individual linear force-velocity and polynomial power-velocity relationships were determined for both movements from push-off mean force and velocity measured continuously with a pressure sensor and linear encoder. Maximal power output, theoretical maximal force and velocity, force-velocity profile and optimal velocity were computed. During the squat, maximal power output (17.7±3.59 vs. 10.9±1.39 W·kg -1 ), theoretical maximal velocity (1.66±0.29 vs. 0.88±0.18 m·s -1 ), optimal velocity (0.839±0.144 vs. 0.465±0.107 m·s -1 ), and force-velocity profile (-27.2±8.5 vs. -64.3±29.5 N·s·m -1 ·kg -1 ) values were significantly higher than during the leg press (p=0.000, effect size=1.72-3.23), whereas theoretical maximal force values (43.1±8.6 vs. 51.9±14.0 N·kg -1 , p=0.034, effect size=0.75) were significantly lower. The mechanical capabilities of the lower-limb extensors were different in the squat compared with the leg press with higher maximal power due to much higher velocity capabilities (e.g. ability to produce force at high velocities) even if moderately lower maximal force qualities. © Georg Thieme Verlag KG Stuttgart · New York.

  5. The study of dynamic force acted on water strider leg departing from water surface

    Directory of Open Access Journals (Sweden)

    Peiyuan Sun

    2018-01-01

    Full Text Available Water-walking insects such as water striders can skate on the water surface easily with the help of the hierarchical structure on legs. Numerous theoretical and experimental studies show that the hierarchical structure would help water strider in quasi-static case such as load-bearing capacity. However, the advantage of the hierarchical structure in the dynamic stage has not been reported yet. In this paper, the function of super hydrophobicity and the hierarchical structure was investigated by measuring the adhesion force of legs departing from the water surface at different lifting speed by a dynamic force sensor. The results show that the adhesion force decreased with the increase of lifting speed from 0.02 m/s to 0.4 m/s, whose mechanic is investigated by Energy analysis. In addition, it can be found that the needle shape setae on water strider leg can help them depart from water surface easily. Thus, it can serve as a starting point to understand how the hierarchical structure on the legs help water-walking insects to jump upward rapidly to avoid preying by other insects.

  6. The study of dynamic force acted on water strider leg departing from water surface

    Science.gov (United States)

    Sun, Peiyuan; Zhao, Meirong; Jiang, Jile; Zheng, Yelong

    2018-01-01

    Water-walking insects such as water striders can skate on the water surface easily with the help of the hierarchical structure on legs. Numerous theoretical and experimental studies show that the hierarchical structure would help water strider in quasi-static case such as load-bearing capacity. However, the advantage of the hierarchical structure in the dynamic stage has not been reported yet. In this paper, the function of super hydrophobicity and the hierarchical structure was investigated by measuring the adhesion force of legs departing from the water surface at different lifting speed by a dynamic force sensor. The results show that the adhesion force decreased with the increase of lifting speed from 0.02 m/s to 0.4 m/s, whose mechanic is investigated by Energy analysis. In addition, it can be found that the needle shape setae on water strider leg can help them depart from water surface easily. Thus, it can serve as a starting point to understand how the hierarchical structure on the legs help water-walking insects to jump upward rapidly to avoid preying by other insects.

  7. Contribution of Leg-Muscle Forces to Paddle Force and Kayak Speed During Maximal-Effort Flat-Water Paddling.

    Science.gov (United States)

    Nilsson, Johnny E; Rosdahl, Hans G

    2016-01-01

    The purpose was to investigate the contribution of leg-muscle-generated forces to paddle force and kayak speed during maximal-effort flat-water paddling. Five elite male kayakers at national and international level participated. The participants warmed up at progressively increasing speeds and then performed a maximal-effort, nonrestricted paddling sequence. This was followed after 5 min rest by a maximal-effort paddling sequence with the leg action restricted--the knee joints "locked." Left- and right-side foot-bar and paddle forces were recorded with specially designed force devices. In addition, knee angular displacement of the right and left knees was recorded with electrogoniometric technique, and the kayak speed was calculated from GPS signals sampled at 5 Hz. The results showed that reduction in both push and pull foot-bar forces resulted in a reduction of 21% and 16% in mean paddle-stroke force and mean kayak speed, respectively. Thus, the contribution of foot-bar force from lower-limb action significantly contributes to kayakers' paddling performance.

  8. Kinesio Taping effects on knee extension force among soccer players

    Directory of Open Access Journals (Sweden)

    Maysa V. G. B. Serra

    2015-04-01

    Full Text Available Background : Kinesio Taping (KT is widely used, however the effects of KT on muscle activation and force are contradictory. Objective : To evaluate the effects of KT on knee extension force in soccer players. Method: This is a clinical trial study design. Thirty-four subjects performed two maximal isometric voluntary contractions of the lower limbs pre, immediately post, and 24 hours after tape application on the lower limbs. Both lower limbs were taped, using K-Tape and 3M Micropore tape randomly on the right and left thighs of the participants. Isometric knee extension force was measured for dominant side using a strain gauge. The following variables were assessed: peak force, time to peak force, rate of force development until peak force, time to peak rate of force development, and 200 ms pulse. Results : There were no statistically significant differences in the variables assessed between KT and Micropore conditions (F=0.645, p=0.666 or among testing sessions (pre, post, and 24h after (F=0.528, p=0.868, and there was no statistical significance (F=0.271, p=0.986 for interaction between tape conditions and testing session. Conclusion: KT did not affect the force-related measures assessed immediately and 24 hours after the KT application compared with Micropore application, during maximal isometric voluntary knee extension.

  9. Bilateral and unilateral vertical ground reaction forces and leg asymmetries in soccer players

    Directory of Open Access Journals (Sweden)

    J Yanci

    2016-04-01

    Full Text Available The purposes of this study were to assess unilateral and bilateral vertical jump performance characteristics, and to compare the vertical ground reaction force characteristics of the impulse and landing phase of a vertical jump between the dominant and non-dominant leg in soccer players. The sample consisted of 20 male soccer players (22.80 ± 2.71 years, 1.88 ± 0.06 m, 76.47 ± 8.80 kg who competed in the third division of the Spanish football league. Vertical jump performance was determined by testing the impulse and landing phase of a bilateral vertical jump, dominant leg vertical jump and non-dominant leg vertical jump. Significant differences (p < 0.05 between dominant and non-dominant legs were found in counter movement jump (CMJ flight time (LA = -2.38%, d = 0.33, CMJ flight height (LA = -4.55%, d = 0.33 and CMJ speed take-off (LA = -2.91%, d = 0.42. No significant differences were found between the dominant and non-dominant leg in the F1 and F2 magnitudes during the landing phase, the time from the first contact of the foot with the ground to the production of F1, the time from the second contact of the foot with the ground to the production of F2, and the time to stabilization of the landing phase. Although differences were found between the dominant and non-dominant leg in the impulse phase of the jump, no significant differences were found between dominant and non-dominant legs in the landing phase of vertical jump variables.

  10. Application of force-length curve for determination of leg stiffness during a vertical jump.

    Science.gov (United States)

    Struzik, Artur; Zawadzki, Jerzy

    2016-01-01

    The aim of this study was to present the methodology for estimation of a leg stiffness during a countermovement jump. The question was asked whether leg stiffness in the countermovement and take-off phases are similar to each other as demonstrated in previous reports. It was also examined whether the stiffness in left lower limb is similar to the one in right lower limb. The research was conducted on 35 basketball players. Each participant performed three countermovement jumps with arm swing to the maximum height. Measurements employed a Kistlerforce plate and a BTS SMART system for motion analysis. Leg stiffness (understood as an inclination of the curve of ground reaction forces vs. length) was computed for these parts of countermovement and take-off phases where its value was relatively constant and F(Δl) relationship was similar to linear. Mean value (±SD) of total stiffness of both lower limbs in the countermovement phase was 7.1 ± 2.3 kN/m, whereas this value in the take-off phase was 7.5 ± 1 kN/m. No statistically significant differences were found between the leg stiffness in the countermovement and the take-off phases. No statistically significant differences were found during the comparison of the stiffness in the right and left lower limb. The calculation methodology allows us to estimate the value of leg stiffness based on the actual shape of F(Δl) curve rather than on extreme values of ΔF and Δl. Despite different tasks of the countermovement and the take-off phases, leg stiffness in these phases is very similar. Leg stiffness during a single vertical jump maintains a relatively constant value in the parts with a small value of acceleration.

  11. Predicting muscle forces during the propulsion phase of single leg triple hop test.

    Science.gov (United States)

    Alvim, Felipe Costa; Lucareli, Paulo Roberto Garcia; Menegaldo, Luciano Luporini

    2018-01-01

    Functional biomechanical tests allow the assessment of musculoskeletal system impairments in a simple way. Muscle force synergies associated with movement can provide additional information for diagnosis. However, such forces cannot be directly measured noninvasively. This study aims to estimate muscle activations and forces exerted during the preparation phase of the single leg triple hop test. Two different approaches were tested: static optimization (SO) and computed muscle control (CMC). As an indirect validation, model-estimated muscle activations were compared with surface electromyography (EMG) of selected hip and thigh muscles. Ten physically healthy active women performed a series of jumps, and ground reaction forces, kinematics and EMG data were recorded. An existing OpenSim model with 92 musculotendon actuators was used to estimate muscle forces. Reflective markers data were processed using the OpenSim Inverse Kinematics tool. Residual Reduction Algorithm (RRA) was applied recursively before running the SO and CMC. For both, the same adjusted kinematics were used as inputs. Both approaches presented similar residuals amplitudes. SO showed a closer agreement between the estimated activations and the EMGs of some muscles. Due to inherent EMG methodological limitations, the superiority of SO in relation to CMC can be only hypothesized. It should be confirmed by conducting further studies comparing joint contact forces. The workflow presented in this study can be used to estimate muscle forces during the preparation phase of the single leg triple hop test and allows investigating muscle activation and coordination. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Pelvic movement strategies and leg extension power in patients with end-stage medial compartment knee osteoarthritis

    DEFF Research Database (Denmark)

    Kierkegaard, Signe; Jørgensen, Peter Bo; Dalgas, Ulrik

    2015-01-01

    INTRODUCTION: During movement tasks, patients with medial compartment knee osteoarthritis use compensatory strategies to minimise the joint load of the affected leg. Movement strategies of the knees and trunk have been investigated, but less is known about movement strategies of the pelvis during...... compartment knee osteoarthritis use greater pelvic movements during advanced functional performance tests, particularly when these involve descending tasks. Further studies should investigate if it is possible to alter these movement strategies by an intervention aimed at increasing strength and power...... advancing functional tasks, and how these strategies are associated with leg extension power. The aim of the study was to investigate pelvic movement strategies and leg extension power in patients with end-stage medial compartment knee osteoarthritis compared with controls. MATERIALS AND METHODS: 57...

  13. Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

    OpenAIRE

    Jingtao Lei; Jianmin Zhu

    2017-01-01

    Pneumatic artificial muscles (PAMs) have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and d...

  14. Self-Described Differences Between Legs in Ballet Dancers: Do They Relate to Postural Stability and Ground Reaction Force Measures?

    Science.gov (United States)

    Mertz, Laura; Docherty, Carrie

    2012-12-01

    Ballet technique classes are designed to train dancers symmetrically, but they may actually create a lateral bias. It is unknown whether dancers in general are functionally asymmetrical, or how an individual dancer's perceived imbalance between legs might manifest itself. The purpose of this study was to examine ballet dancers' lateral preference by analyzing their postural stability and ground reaction forces in fifth position when landing from dance-specific jumps. Thirty university ballet majors volunteered to participate in this study. The subjects wore their own ballet technique shoes and performed fundamental ballet jumps out of fifth position on a force plate. The force plate recorded center of pressure (COP) and ground reaction force (GRF) data. Each subject completed a laterality questionnaire that determined his or her preferred landing leg for ballet jumps, self-identified stronger leg, and self-identified leg with better balance. All statistical comparisons were made between the leg indicated on the laterality questionnaire and the other leg (i.e., if the dancer's response to a question was "left," the comparison was made with the left leg as the "preferred" leg and the right leg as the "non-preferred leg"). No significant differences were identified between the limbs in any of the analyses conducted (all statistical comparisons produced p values > 0.05). The results of this study indicate that a dancer's preferential use of one limb over the other has no bearing on GRFs or balance ability after landing jumps in ballet. Similarly, dancers' opinions of their leg characteristics (such as one leg being stronger than the other) seem not to correlate with the dancers' actual ability to absorb GRFs or to balance when landing from ballet jumps.

  15. Optimal Resistive Forces for Maximizing the Reliability of Leg Muscles' Capacities Tested on a Cycle Ergometer.

    Science.gov (United States)

    García-Ramos, Amador; Torrejón, Alejandro; Morales-Artacho, Antonio J; Pérez-Castilla, Alejandro; Jaric, Slobodan

    2018-02-01

    This study determined the optimal resistive forces for testing muscle capacities through the standard cycle ergometer test (1 resistive force applied) and a recently developed 2-point method (2 resistive forces used for force-velocity modelling). Twenty-six men were tested twice on maximal sprints performed on a leg cycle ergometer against 5 flywheel resistive forces (R1-R5). The reliability of the cadence and maximum power measured against the 5 individual resistive forces, as well as the reliability of the force-velocity relationship parameters obtained from the selected 2-point methods (R1-R2, R1-R3, R1-R4, and R1-R5), were compared. The reliability of outcomes obtained from individual resistive forces was high except for R5. As a consequence, the combination of R1 (≈175 rpm) and R4 (≈110 rpm) provided the most reliable 2-point method (CV: 1.46%-4.04%; ICC: 0.89-0.96). Although the reliability of power capacity was similar for the R1-R4 2-point method (CV: 3.18%; ICC: 0.96) and the standard test (CV: 3.31%; ICC: 0.95), the 2-point method should be recommended because it also reveals maximum force and velocity capacities. Finally, we conclude that the 2-point method in cycling should be based on 2 distant resistive forces, but avoiding cadences below 110 rpm.

  16. Posture effects on spontaneous limb movements, alternated stepping, and the leg extension response in neonatal rats.

    Science.gov (United States)

    Mendez-Gallardo, Valerie; Roberto, Megan E; Kauer, Sierra D; Brumley, Michele R

    2016-03-01

    The development of postural control is considered an important factor for the expression of coordinated behavior such as locomotion. In the natural setting of the nest, newborn rat pups adapt their posture to perform behaviors of ecological relevance such as those related to suckling. The current study explores the role of posture in the expression of three behaviors in the newborn rat: spontaneous limb activity, locomotor-like stepping behavior, and the leg extension response (LER). One-day-old rat pups were tested in one of two postures--prone or supine--on each of these behavioral measures. Results showed that pups expressed more spontaneous activity while supine, more stepping while prone, and no differences in LER expression between the two postures. Together these findings show that posture affects the expression of newborn behavior patterns in different ways, and suggest that posture may act as a facilitator or a limiting factor in the expression of different behaviors during early development. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Swing-leg trajectory of running guinea fowl suggests task-level priority of force regulation rather than disturbance rejection.

    Directory of Open Access Journals (Sweden)

    Yvonne Blum

    Full Text Available To achieve robust and stable legged locomotion in uneven terrain, animals must effectively coordinate limb swing and stance phases, which involve distinct yet coupled dynamics. Recent theoretical studies have highlighted the critical influence of swing-leg trajectory on stability, disturbance rejection, leg loading and economy of walking and running. Yet, simulations suggest that not all these factors can be simultaneously optimized. A potential trade-off arises between the optimal swing-leg trajectory for disturbance rejection (to maintain steady gait versus regulation of leg loading (for injury avoidance and economy. Here we investigate how running guinea fowl manage this potential trade-off by comparing experimental data to predictions of hypothesis-based simulations of running over a terrain drop perturbation. We use a simple model to predict swing-leg trajectory and running dynamics. In simulations, we generate optimized swing-leg trajectories based upon specific hypotheses for task-level control priorities. We optimized swing trajectories to achieve i constant peak force, ii constant axial impulse, or iii perfect disturbance rejection (steady gait in the stance following a terrain drop. We compare simulation predictions to experimental data on guinea fowl running over a visible step down. Swing and stance dynamics of running guinea fowl closely match simulations optimized to regulate leg loading (priorities i and ii, and do not match the simulations optimized for disturbance rejection (priority iii. The simulations reinforce previous findings that swing-leg trajectory targeting disturbance rejection demands large increases in stance leg force following a terrain drop. Guinea fowl negotiate a downward step using unsteady dynamics with forward acceleration, and recover to steady gait in subsequent steps. Our results suggest that guinea fowl use swing-leg trajectory consistent with priority for load regulation, and not for steadiness of gait

  18. Swing-Leg Trajectory of Running Guinea Fowl Suggests Task-Level Priority of Force Regulation Rather than Disturbance Rejection

    Science.gov (United States)

    Blum, Yvonne; Vejdani, Hamid R.; Birn-Jeffery, Aleksandra V.; Hubicki, Christian M.; Hurst, Jonathan W.; Daley, Monica A.

    2014-01-01

    To achieve robust and stable legged locomotion in uneven terrain, animals must effectively coordinate limb swing and stance phases, which involve distinct yet coupled dynamics. Recent theoretical studies have highlighted the critical influence of swing-leg trajectory on stability, disturbance rejection, leg loading and economy of walking and running. Yet, simulations suggest that not all these factors can be simultaneously optimized. A potential trade-off arises between the optimal swing-leg trajectory for disturbance rejection (to maintain steady gait) versus regulation of leg loading (for injury avoidance and economy). Here we investigate how running guinea fowl manage this potential trade-off by comparing experimental data to predictions of hypothesis-based simulations of running over a terrain drop perturbation. We use a simple model to predict swing-leg trajectory and running dynamics. In simulations, we generate optimized swing-leg trajectories based upon specific hypotheses for task-level control priorities. We optimized swing trajectories to achieve i) constant peak force, ii) constant axial impulse, or iii) perfect disturbance rejection (steady gait) in the stance following a terrain drop. We compare simulation predictions to experimental data on guinea fowl running over a visible step down. Swing and stance dynamics of running guinea fowl closely match simulations optimized to regulate leg loading (priorities i and ii), and do not match the simulations optimized for disturbance rejection (priority iii). The simulations reinforce previous findings that swing-leg trajectory targeting disturbance rejection demands large increases in stance leg force following a terrain drop. Guinea fowl negotiate a downward step using unsteady dynamics with forward acceleration, and recover to steady gait in subsequent steps. Our results suggest that guinea fowl use swing-leg trajectory consistent with priority for load regulation, and not for steadiness of gait. Swing-leg

  19. Effects of combined and classic training on different isometric rate of force development parameters of leg extensors in female volleyball players: Discriminative analysis approach

    Directory of Open Access Journals (Sweden)

    Rajić Branislav

    2013-01-01

    Full Text Available Background: The aim of this study is to verify the effects of the combined and classic training of different isometric rates of force development (RFD parameters of legs. Materials and Methods: Three groups of female athletes was tested: Experimental group (N = 12, classically trained group (N = 11, and control group (N = 20 of athletes. The isometric "standing leg extension" and "Rise on Toes" tests were conducted to evaluate the maximal force, time necessary time to reach it and the RFD analyzed at 100 ms, 180 ms, 250 ms from the onset, and 50-100% of its maximal result. Results: The maximal RFD of legs and calves are dominant explosive parameters. Special training enhanced the RFD of calves of GROUP SPEC at 100 ms (P = 0.05, at 180 ms (P = 0.039, at 250 ms (P = 0.039, at 50% of the F max (P = 0.031 and the F max (P = 0.05. Domination of GROUP SPEC toward GROUP CLASS and GROUP CONTROL is in case of legs at 100 ms (P = 0.04; at 180 ms (P = 0.04; at 250 ms (P = 0.00; at 50% of the F max (P = 0.01 and at the F max (P = 0.00; in case of calves at 100 ms (P = 0.07; 180 ms (P = 0.001; at 250 ms (P = 0.00; at 50% of the F max (P = 0.00 and at F max (P = 0.000. Conclusion: Dominant explosive factors are maximal RFD of leg extensors and calves, and legs at 250ms. Specific training enhanced explosiveness of calves of GROUP SPEC general and partial domination of GROUP SPEC by 87% over GROUP CLASS , and 35% over GROUP CONTROL .

  20. Integrin extension enables ultrasensitive regulation by cytoskeletal force.

    Science.gov (United States)

    Li, Jing; Springer, Timothy A

    2017-05-02

    Integrins undergo large-scale conformational changes upon activation. Signaling events driving integrin activation have previously been discussed conceptually, but not quantitatively. Here, recent measurements of the intrinsic ligand-binding affinity and free energy of each integrin conformational state on the cell surface, together with the length scales of conformational change, are used to quantitatively compare models of activation. We examine whether binding of cytoskeletal adaptors to integrin cytoplasmic domains is sufficient for activation or whether exertion of tensile force by the actin cytoskeleton across the integrin-ligand complex is also required. We find that only the combination of adaptor binding and cytoskeletal force provides ultrasensitive regulation. Moreover, switch-like activation by force depends on the large, >130 Å length-scale change in integrin extension, which is well tailored to match the free-energy difference between the inactive (bent-closed) and active (extended-open) conformations. The length scale and energy cost in integrin extension enable activation by force in the low pN range and appear to be the key specializations that enable cell adhesion through integrins to be coordinated with cytoskeletal dynamics.

  1. Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers.

    Science.gov (United States)

    Zhang, Songning; Clowers, Kurt G; Powell, Douglas

    2006-12-01

    Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (pboots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.

  2. Human Leg Model Predicts Muscle Forces, States, and Energetics during Walking.

    Science.gov (United States)

    Markowitz, Jared; Herr, Hugh

    2016-05-01

    Humans employ a high degree of redundancy in joint actuation, with different combinations of muscle and tendon action providing the same net joint torque. Both the resolution of these redundancies and the energetics of such systems depend on the dynamic properties of muscles and tendons, particularly their force-length relations. Current walking models that use stock parameters when simulating muscle-tendon dynamics tend to significantly overestimate metabolic consumption, perhaps because they do not adequately consider the role of elasticity. As an alternative, we posit that the muscle-tendon morphology of the human leg has evolved to maximize the metabolic efficiency of walking at self-selected speed. We use a data-driven approach to evaluate this hypothesis, utilizing kinematic, kinetic, electromyographic (EMG), and metabolic data taken from five participants walking at self-selected speed. The kinematic and kinetic data are used to estimate muscle-tendon lengths, muscle moment arms, and joint moments while the EMG data are used to estimate muscle activations. For each subject we perform an optimization using prescribed skeletal kinematics, varying the parameters that govern the force-length curve of each tendon as well as the strength and optimal fiber length of each muscle while seeking to simultaneously minimize metabolic cost and maximize agreement with the estimated joint moments. We find that the metabolic cost of transport (MCOT) values of our participants may be correctly matched (on average 0.36±0.02 predicted, 0.35±0.02 measured) with acceptable joint torque fidelity through application of a single constraint to the muscle metabolic budget. The associated optimal muscle-tendon parameter sets allow us to estimate the forces and states of individual muscles, resolving redundancies in joint actuation and lending insight into the potential roles and control objectives of the muscles of the leg throughout the gait cycle.

  3. Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

    Directory of Open Access Journals (Sweden)

    Jingtao Lei

    2017-03-01

    Full Text Available Pneumatic artificial muscles (PAMs have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and dynamic jumping performance. The experimental platform of PAM is conducted, and the static equal pressure experiments are performed to obtain the PAM force model. According to the testing data, parameter identification method is adopted to determine the force model of PAM. A simulation on the position and stiffness control of the knee joint is performed, and the simulation results show the effectiveness of the presented method.

  4. 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.

  5. Research on the Obstacle Negotiation Strategy for the Heavy-duty Six-legged Robot based on Force Control

    Directory of Open Access Journals (Sweden)

    Li Mantian

    2017-01-01

    Full Text Available To make heavy-duty six-legged robots without environment reconstruction system negotiate obstacles after the earthquake successfully, an obstacle negotiation strategy is described in this paper. The reflection strategy is generated by the information of plantar force sensors and Bezier Curve is used to plan trajectory. As the heavy-duty six-legged robot has a large inertia, force controller is necessary to ensure the robot not to lose stability while negotiating obstacles. Impedance control is applied to reduce the impact of collision and active force control is applied to adjust the pose of the robot. The robot can walk through zones that are filled with obstacles automatically because of force control. Finally, the algorithm is verified in a simulation environment.

  6. Why is the force-velocity relationship in leg press tasks quasi-linear rather than hyperbolic?

    NARCIS (Netherlands)

    Bobbert, M.F.

    2012-01-01

    Force-velocity relationships reported in the literature for functional tasks involving a combination of joint rotations tend to be quasilinear. The purpose of this study was to explain why they are not hyperbolic, like Hill's relationship. For this purpose, a leg press task was simulated with a

  7. Improvements in force variability and structure from vision- to memory-guided submaximal isometric knee extension in subacute stroke.

    Science.gov (United States)

    Chow, John W; Stokic, Dobrivoje S

    2018-03-01

    We examined changes in variability, accuracy, frequency composition, and temporal regularity of force signal from vision-guided to memory-guided force-matching tasks in 17 subacute stroke and 17 age-matched healthy subjects. Subjects performed a unilateral isometric knee extension at 10, 30, and 50% of peak torque [maximum voluntary contraction (MVC)] for 10 s (3 trials each). Visual feedback was removed at the 5-s mark in the first two trials (feedback withdrawal), and 30 s after the second trial the subjects were asked to produce the target force without visual feedback (force recall). The coefficient of variation and constant error were used to quantify force variability and accuracy. Force structure was assessed by the median frequency, relative spectral power in the 0-3-Hz band, and sample entropy of the force signal. At 10% MVC, the force signal in subacute stroke subjects became steadier, more broadband, and temporally more irregular after the withdrawal of visual feedback, with progressively larger error at higher contraction levels. Also, the lack of modulation in the spectral frequency at higher force levels with visual feedback persisted in both the withdrawal and recall conditions. In terms of changes from the visual feedback condition, the feedback withdrawal produced a greater difference between the paretic, nonparetic, and control legs than the force recall. The overall results suggest improvements in force variability and structure from vision- to memory-guided force control in subacute stroke despite decreased accuracy. Different sensory-motor memory retrieval mechanisms seem to be involved in the feedback withdrawal and force recall conditions, which deserves further study. NEW & NOTEWORTHY We demonstrate that in the subacute phase of stroke, force signals during a low-level isometric knee extension become steadier, more broadband in spectral power, and more complex after removal of visual feedback. Larger force errors are produced when recalling

  8. Molecular shape and binding force of Mycoplasma mobile's leg protein Gli349 revealed by an AFM study

    International Nuclear Information System (INIS)

    Lesoil, Charles; Nonaka, Takahiro; Sekiguchi, Hiroshi; Osada, Toshiya; Miyata, Makoto; Afrin, Rehana; Ikai, Atsushi

    2010-01-01

    Recent studies of the gliding bacteria Mycoplasma mobile have identified a family of proteins called the Gli family which was considered to be involved in this novel and yet fairly unknown motility system. The 349 kDa protein called Gli349 was successfully isolated and purified from the bacteria, and electron microscopy imaging and antibody experiments led to the hypothesis that it acts as the 'leg' of M. mobile, responsible for attachment to the substrate as well as for gliding motility. However, more precise evidence of the molecular shape and function of this protein was required to asses this theory any further. In this study, an atomic force microscope (AFM) was used both as an imaging and a force measurement device to provide new information about Gli349 and its role in gliding motility. AFM images of the protein were obtained revealing a complex structure with both rigid and flexible parts, consistent with previous electron micrographs of the protein. Single-molecular force spectroscopy experiments were also performed, revealing that Gli349 is able to specifically bind to sialyllactose molecules and withstand unbinding forces around 70 pN. These findings strongly support the idea that Gli349 is the 'leg' protein of M. mobile, responsible for binding and also most probably force generation during gliding motility.

  9. Prognostic implications of the Quebec Task Force classification of back-related leg pain

    DEFF Research Database (Denmark)

    Kongsted, Alice; Kent, Peter; Jensen, Tue Secher

    2013-01-01

    or below the knee. CONCLUSIONS: Subgrouping LBP patients, based on pain location and neurological signs, was associated with activity limitation and sick leave, but not with GPE. The presence of neurological signs and pain in the leg both have prognostic implications but whether that leg pain without...... if this was explained by measured baseline factors. METHODS: Routine clinical data were collected during the first visit to an outpatient department and follow-ups were performed after 3 and 12 months. Patients were divided into the four subgroups and associations between subgroups and the outcomes of activity...... limitation, global perceived effect (GPE) after 3 months, and sick leave after 3 months were tested by means of generalised estimating equations. Models were univariate (I), adjusted for duration (II), and adjusted for all baseline differences (III). RESULTS: A total of 1,752 patients were included...

  10. Assessing the force-velocity characteristics of the leg extensors in well-trained athletes: the incremental load power profile.

    Science.gov (United States)

    Sheppard, Jeremy M; Cormack, Stuart; Taylor, Kristie-Lee; McGuigan, Michael R; Newton, Robert U

    2008-07-01

    The purpose of this research project was to evaluate the methodology of an iso-inertial force-velocity assessment utilizing a range of loads and a group of high-performance athletes. A total of 26 subjects (19.8 +/- 2.6 years, 196.3 +/- 9.6 cm, 88.6 +/- 8.9 kg) participated in this study. Interday reliability of various force-time measures obtained during the performance of countermovement jumps with a range of loads was examined, followed by a validity assessment of the various measures' ability to discriminate among performance levels, while the ability of the test protocol to detect training-induced changes was assessed by comparing results before and after an intensive 12-week training period. Force and velocity variables were observed to be reliable (intraclass correlation coefficient 0.74-0.99). Large effect size statistic (ES > 0.50) differences among player groups were observed for peak power (1.36-2.25), relative peak power (1.57-2.42), and peak force (0.74-0.95). Significant (p 0.50) improvements were observed in the kinetic values after the intensive training period. The results of this study indicate that the incremental load power profile is an acceptably reliable, valid, and sensitive method of assessing force and power capabilities of the leg extensors in high-performance and elite volleyball players.

  11. Trunk and hip muscle recruitment patterns during the prone leg extension following a lateral ankle sprain: A prospective case study pre and post injury

    Directory of Open Access Journals (Sweden)

    Lehman Gregory J

    2006-02-01

    Full Text Available Abstract Background and case presentation The prone leg extension (PLE is commonly used to identify dysfunction of muscle recruitment patterns. The prone leg extension is theorized to identify proximal muscle disturbances which are a result of distal injury or dysfunction (i.e. an ankle sprain. This case study compares the trunk and hip muscle (bilateral lower erector spine, ipsilateral hamstring and ipsilateral gluteus maximus timing during a PLE of a 27 year old female runner during a healthy state (pre ankle sprain and 2 and 8 weeks post ankle sprain. Results and discussion The gluteus maximus muscle onsets at 8 weeks post injury appeared to occur earlier compared with 2 weeks post injury. The Right Erector Spinae at 8 weeks post injury was also active earlier compared with the participant's non-injured state. A large degree of variability can be noted within trials on the same day for all muscle groups. Conclusion An acute ankle injury did not result in a delay in gluteus maximus muscle activation. The utility of the prone leg extension as a clinical and functional test is questionable due to the normal variability seen during the test and our current inability to determine what is normal and what is dysfunctional.

  12. Trunk and hip muscle recruitment patterns during the prone leg extension following a lateral ankle sprain: A prospective case study pre and post injury

    Science.gov (United States)

    Lehman, Gregory J

    2006-01-01

    Background and case presentation The prone leg extension (PLE) is commonly used to identify dysfunction of muscle recruitment patterns. The prone leg extension is theorized to identify proximal muscle disturbances which are a result of distal injury or dysfunction (i.e. an ankle sprain). This case study compares the trunk and hip muscle (bilateral lower erector spine, ipsilateral hamstring and ipsilateral gluteus maximus) timing during a PLE of a 27 year old female runner during a healthy state (pre ankle sprain) and 2 and 8 weeks post ankle sprain. Results and discussion The gluteus maximus muscle onsets at 8 weeks post injury appeared to occur earlier compared with 2 weeks post injury. The Right Erector Spinae at 8 weeks post injury was also active earlier compared with the participant's non-injured state. A large degree of variability can be noted within trials on the same day for all muscle groups. Conclusion An acute ankle injury did not result in a delay in gluteus maximus muscle activation. The utility of the prone leg extension as a clinical and functional test is questionable due to the normal variability seen during the test and our current inability to determine what is normal and what is dysfunctional. PMID:16504168

  13. The relationship of force output characteristics during a sit-to-stand movement with lower limb muscle mass and knee joint extension in the elderly.

    Science.gov (United States)

    Yamada, Takayoshi; Demura, Shinichi

    2010-01-01

    This study examined the reliability of ground reaction force (GRF) parameters during sit-to-stand (STS) movements and the relationships between the GRF parameters and lower limb muscle mass and knee extension muscle strength. Fifty elderly females performed an STS movement twice from a chair adjusted to their knee height and the GRF, lower limb muscle mass and isometric knee extension muscle strength were measured. Reliabilities of GRF parameters were high (intra-class correlation coefficient=ICC=0.70-0.95). Parameters on force output during trunk flexion phase (ground reaction force at hip-lift off, sum of force output between beginning of STS movement and hip-lift off) differed significantly between trials, but their effect sizes were small (0.15-0.23). GRF parameters during hip-lift off and knee-hip joint extension phases significantly correlated with knee extension strength (|r|=0.29-0.64) but not lower limb muscle mass. In conclusion, the reliability of GRF during STS movement is good in hip-lift off and knee-hip joint extension phases and these phases relate significantly with lower limb muscle function. These two phases are useful for evaluation of leg muscle function of the elderly. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  14. Roughness in Surface Force Measurements: Extension of DLVO Theory To Describe the Forces between Hafnia Surfaces.

    Science.gov (United States)

    Eom, Namsoon; Parsons, Drew F; Craig, Vincent S J

    2017-07-06

    The interaction between colloidal particles is commonly viewed through the lens of DLVO theory, whereby the interaction is described as the sum of the electrostatic and dispersion forces. For similar materials acting across a medium at pH values remote from the isoelectric point the theory typically involves an electrostatic repulsion that is overcome by dispersion forces at very small separations. However, the dominance of the dispersion forces at short separations is generally not seen in force measurements, with the exception of the interaction between mica surfaces. The discrepancy for silica surfaces has been attributed to hydration forces, but this does not explain the situation for titania surfaces where the dispersion forces are very much larger. Here, the interaction forces between very smooth hafnia surfaces have been measured using the colloid probe technique and the forces evaluated within the DLVO framework, including both hydration forces and the influence of roughness. The measured forces across a wide range of pH at different salt concentrations are well described with a single parameter for the surface roughness. These findings show that even small degrees of surface roughness significantly alter the form of the interaction force and therefore indicate that surface roughness needs to be included in the evaluation of surface forces between all surfaces that are not ideally smooth.

  15. Dual-energy X-ray absorptiometry and force-plate analysis of gait in dogs with healed femora after leg-lengthening plate fixation

    International Nuclear Information System (INIS)

    Muir, P.; Markel, M.D.; Bogdanske, J.J.; Johnson, K.A.

    1995-01-01

    Dual-energy x-ray absorptiometry was used to measure bone mineral density of four regions in healed femora of nine dogs after fracture fixation with a leg-lengthening plate. Six to 85 months (mean, 46 months) after surgery, the bone mineral density of healed femora was not significantly different from the contralateral uninjured femora (P > .05; power = 0.8 at delta = 15%). Radiolucencies around the proximal screws, apparently associated with screw loosening, were seen on radiographic views of the healed femora of three dogs. In one of these dogs, one screw in the proximal metaphysis had broken. Force-plate analysis of gait was also performed on dogs at the time of bone mineral density measurement. Peak vertical force was decreased in the pelvic limb with the healed fracture compared with the contralateral unoperated limb (P < 0.05). Clinically apparent lameness in three dogs did not appear to be associated with altered bone mineral density and may have been caused by hip osteoarthritis, a nondisplaced hairline diaphyseal fracture, and screw loosening in conjunction with extensive post-traumatic soft tissue injury

  16. Venogram - leg

    Science.gov (United States)

    Phlebogram - leg; Venography - leg; Angiogram - leg ... into a vein in the foot of the leg being looked at. An intravenous (IV) line is ... vein. A tourniquet may be placed on your leg so the dye flows into the deeper veins. ...

  17. Hierarchical atom type definitions and extensible all-atom force fields.

    Science.gov (United States)

    Jin, Zhao; Yang, Chunwei; Cao, Fenglei; Li, Feng; Jing, Zhifeng; Chen, Long; Shen, Zhe; Xin, Liang; Tong, Sijia; Sun, Huai

    2016-03-15

    The extensibility of force field is a key to solve the missing parameter problem commonly found in force field applications. The extensibility of conventional force fields is traditionally managed in the parameterization procedure, which becomes impractical as the coverage of the force field increases above a threshold. A hierarchical atom-type definition (HAD) scheme is proposed to make extensible atom type definitions, which ensures that the force field developed based on the definitions are extensible. To demonstrate how HAD works and to prepare a foundation for future developments, two general force fields based on AMBER and DFF functional forms are parameterized for common organic molecules. The force field parameters are derived from the same set of quantum mechanical data and experimental liquid data using an automated parameterization tool, and validated by calculating molecular and liquid properties. The hydration free energies are calculated successfully by introducing a polarization scaling factor to the dispersion term between the solvent and solute molecules. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  18. Trunk position modulates anterior cruciate ligament forces and strains during a single-leg squat

    NARCIS (Netherlands)

    Kulas, Anthony S.; Hortobagyi, Tibor; DeVita, Paul

    Background: Although the squat exercise and its variations are commonly prescribed for anterior cruciate ligament rehabilitation, whether trunk position affects these ligament forces and strains during the squat is unclear. Our purpose was to evaluate the effects of trunk position on anterior

  19. Estimation of the forces acting on the tibiofemoral joint during knee extension exercises

    Directory of Open Access Journals (Sweden)

    Rodrigo Rico Bini

    2008-02-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n1p35 The objectives of this study were to: (1 evaluate the resistive torque of an open kinetic chain strength-training machine for performing knee extensions, and (2 perform an analysis estimating internal forces in the tibiofemoral joint. During a fi rst phase of the study, measurements were taken of the machine under analysis (external forces, and then calculations were performed to estimate forces on the lower limb (internal forces. Equations were defi ned to calculate human force (HF, and the moment of muscular force (MMF. Perpendicular muscular force (MFp and joint force (JFp, axial muscular force (MF” and joint force (JF”, and total muscular force (MF and joint force (JF were all calculated. Five knee angles were analyzed (zero, 30, 45, 60, and 90 degrees. A reduction was observed in HF at higher knee angles, while MF and JF also increased at the same time. HF was always lower than the load selected on the machine, which indicates a reduced overload imposed by the machine. The reduction observed in MFp and JFp at higher knee angles indicates a lower tendency to shear the tibia in relation to the femur. At the same time, there was an increase in JF” due to higher MF”. The biomechanical model proposed in this study has shown itself adequate for the day-to-day needs of professionals who supervise orient strength training.

  20. Effects of carbohydrate supplementation on force output and time to exhaustion during static leg contractions superimposed with electromyostimulation.

    Science.gov (United States)

    Wax, Benjamin; Brown, Stanley P; Webb, Heather E; Kavazis, Andreas N

    2012-06-01

    The purpose of this study was to investigate the effects of carbohydrate ingestion on force output and time to exhaustion using single leg static contractions superimposed with brief periods of electromyostimulation. Six trained male subjects participated in a randomized, counterbalanced, double-blind study. The subjects were randomly assigned to placebo (PL) or carbohydrate (CHO). The subjects in CHO consumed 1 g of carbohydrate per kilogram of body mass loading dose and 0.17 g of carbohydrate per kilogram of body mass every 6 minutes during the exercise protocol. The PL received an equal volume of a solution made of saccharin and aspartame. The exercise protocol consisted of repeated 20-second static contractions of quadriceps muscle at 50% maximal voluntary contraction followed by 40-second rest until failure occurred. Importantly, the force output during quadriceps maximal voluntary contraction strength with superimposed electromyostimulation was measured in the beginning and every 5 minutes during the last 3 seconds of static contractions throughout the exercise protocol. Venous blood samples were taken preexercise, immediately postexercise, and at 5 minutes postexercise and analyzed for blood lactate. Our results indicate that time to exhaustion (PL = 16.0 ± 8.1 minutes; CHO = 29.0 ± 13.1 minutes) and force output (PL = 3,638.7 ± 524.5 N; CHO = 5,540.1 ± 726.1 N) were significantly higher (p static muscle contractions can increase force output and increase time to exhaustion. Therefore, our data suggest that carbohydrate supplementation before and during resistance exercise might help increase the training volume of athletes.

  1. Patellofemoral and tibiofemoral forces during knee extension: simulations to strength training and rehabilitation exercises

    Directory of Open Access Journals (Sweden)

    Rodrigo Rico Bini

    Full Text Available Abstract Introduction: Limited evidence has been shown on ways to optimize the mechanical design of machines in order to minimize knee loads. Objective: This study compared six computer simulated models of open kinetic knee extension exercises for patellofemoral pressure and tibiofemoral forces. Methods: A musculoskeletal model of the lower limb was developed using six different cam radius to change resistive forces. A default machine, a constant cam radius, a torque-angle model, a free-weight model and two optimized models were simulated. Optimized models reduced cam radius at target knee flexion angles to minimize knee forces. Cam radius, human force, tibiofemoral compressive and shear force, and patellofemoral pressure were compared for the six models using data from five knee flexion angles. Results: Large reductions in cam radius comparing the free-weight model to other models (73-180% were limited to the large human force for the constant cam model to other models (9-36%. Larger human force (13 -36% was estimated to perform knee extension using a constant cam radius compared other models without large effects in knee joint forces. Conclusion: Changes in cam design effected human without a potential impact in knee loads.

  2. Are hamstrings activated to counteract shear forces during isometric knee extension efforts in healthy subjects?

    NARCIS (Netherlands)

    Kingma, I.; Aalbersberg-van Berkel, S.; van Dieen, J.H.

    2004-01-01

    The hamstring muscles have the potential to counteract anterior shear forces at the knee joint by co-contracting during knee extension efforts. Such a muscle recruitment pattern might protect the anterior cruciate ligament (ACL) by reducing its strain. In this study we investigated to what extent

  3. Force-extension behavior of DNA in the presence of DNA-bending nucleoid associated proteins

    Science.gov (United States)

    Dahlke, K.; Sing, C. E.

    2018-02-01

    Interactions between nucleoid associated proteins (NAPs) and DNA affect DNA polymer conformation, leading to phenomena such as concentration dependent force-extension behavior. These effects, in turn, also impact the local binding behavior of the protein, such as high forces causing proteins to unbind, or proteins binding favorably to locally bent DNA. We develop a coarse-grained NAP-DNA simulation model that incorporates both force- and concentration-dependent behaviors, in order to study the interplay between NAP binding and DNA conformation. This model system includes multi-state protein binding and unbinding, motivated by prior work, but is now dependent on the local structure of the DNA, which is related to external forces acting on the DNA strand. We observe the expected qualitative binding behavior, where more proteins are bound at lower forces than at higher forces. Our model also includes NAP-induced DNA bending, which affects DNA elasticity. We see semi-quantitative matching of our simulated force-extension behavior to the reported experimental data. By using a coarse-grained simulation, we are also able to look at non-equilibrium behaviors, such as dynamic extension of a DNA strand. We stretch a DNA strand at different rates and at different NAP concentrations to observe how the time scales of the system (such as pulling time and unbinding time) work in concert. When these time scales are similar, we observe measurable rate-dependent changes in the system, which include the number of proteins bound and the force required to extend the DNA molecule. This suggests that the relative time scales of different dynamic processes play an important role in the behavior of NAP-DNA systems.

  4. Quadriceps force during knee extension in different replacement scenarios with a modular partial prosthesis.

    Science.gov (United States)

    Calliess, Tilman; Schado, Ssuheib; Richter, Berna I; Becher, Christoph; Ezechieli, Marco; Ostermeier, Sven

    2014-02-01

    Previous biomechanical studies have shown that bi-cruciate retaining knee replacement does not significantly alter normal knee kinematics, however, there are no data on the influence of a combined medial and patellofemoral bi-compartimental arthroplasty. The purpose of this in vitro study was to evaluate the effect of different replacement scenarios with a modular partial knee replacement system on the amount of quadriceps force required to extend the knee during an isokinetic extension cycle. Ten human knee specimens were tested in a kinematic knee simulator under (1) physiologic condition and after subsequent implantation of (2) a medial unicondylar and (3) a trochlear replacement. An isokinetic extension cycle of the knee with a constant extension moment of 31 Nm was simulated. The resulting quadriceps extension force was measured from 120° to full knee extension. The quadriceps force curve described a typically sinusoidal characteristic before and after each replacement scenario. The isolated medial replacement resulted in a slightly, but significantly higher maximum quadriceps force (1510 N vs. 1585 N, P = 0.006) as well as the subsequent trochlear replacement showed an additional increase (1801 N, P = 0.008). However, for both replacements no significant difference to the untreated condition could be detected in mid-flexion (10-50°). When considering a bi-compartimental replacement an increase of required maximum quadriceps force needed to extend the knee has to keep in mind. However, the close to physiological movement in mid-flexion suggests that patients with a bi-crutiate retaining arthroplasty might have an advantage in knee stability compared to total knee arthroplasty. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Prevention and treatment of exercise related leg pain in young soldiers; a review of the literature and current practice in the Dutch Armed Forces.

    Science.gov (United States)

    Zimmermann, Wes O; Helmhout, P H; Beutler, A

    2017-04-01

    Overuse injuries of the leg are a common problem for young soldiers. This article reviews the literature concerning the prevention and treatment of exercise related leg pain in military settings and presents the latest developments in proposed mechanisms and treatments. Current practice and treatment protocols from the Dutch Armed Forces are reviewed, with an emphasis on the most prevalent conditions of medial tibial stress syndrome and chronic exertional compartment syndrome. The conclusion is that exercise related leg pain in the military is an occupational problem that deserves further study. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  6. Multi-Finger Interaction and Synergies in Finger Flexion and Extension Force Production

    Directory of Open Access Journals (Sweden)

    Jaebum Park

    2017-06-01

    Full Text Available The aim of this study was to discover finger interaction indices during single-finger ramp tasks and multi-finger coordination during a steady state force production in two directions, flexion, and extension. Furthermore, the indices of anticipatory adjustment of elemental variables (i.e., finger forces prior to a quick pulse force production were quantified. It is currently unknown whether the organization and anticipatory modulation of stability properties are affected by force directions and strengths of in multi-finger actions. We expected to observe a smaller finger independency and larger indices of multi-finger coordination during extension than during flexion due to both neural and peripheral differences between the finger flexion and extension actions. We also examined the indices of the anticipatory adjustment between different force direction conditions. The anticipatory adjustment could be a neural process, which may be affected by the properties of the muscles and by the direction of the motions. The maximal voluntary contraction (MVC force was larger for flexion than for extension, which confirmed the fact that the strength of finger flexor muscles (e.g., flexor digitorum profundus was larger than that of finger extensor (e.g., extensor digitorum. The analysis within the uncontrolled manifold (UCM hypothesis was used to quantify the motor synergy of elemental variables by decomposing two sources of variances across repetitive trials, which identifies the variances in the uncontrolled manifold (VUCM and that are orthogonal to the UCM (VORT. The presence of motor synergy and its strength were quantified by the relative amount of VUCM and VORT. The strength of motor synergies at the steady state was larger in the extension condition, which suggests that the stability property (i.e., multi-finger synergies may be a direction specific quantity. However, the results for the existence of anticipatory adjustment; however, no difference

  7. A Comparison of Musculo-Articular Stiffness and Maximal Isometric Plantar Flexion and Knee Extension Force in Dancers and Untrained Individuals.

    Science.gov (United States)

    Rice, Paige E; van Werkhoven, Herman; Dejournette, Denzel J; Gurchiek, Reed D; Mackall, John W; McBride, Jeffrey M

    2017-12-15

    Dance involves a high volume of aesthetic, stretch-shortening cycle (SSC) actions, which may cause unique adaptations to performance. The strength dancers possess to withstand such frequency of SSCs remains elusive. The extensive training that dancers experience from a young age, however, yields anatomical and strength development that may contrast with that of untrained individuals. Therefore, the purpose of this study was to investigate differences in musculo-articular stiffness and maximal isometric plantar flexion and knee extension force between dancers and untrained individuals. A total of 16 females volunteered to participate in the study (N = 8 dancers; N = 8 untrained individuals). Dancers had a minimum of 10 years of dance experience and were currently training at the collegiate dance level three or more times per week. Untrained individuals had no dance background, nor were they currently involved in any form of regularized physical activity. All subjects completed a series of lower leg measurements and strength tests. This included a musculo-articular stiffness measurement using a free-oscillation technique, along with maximal isometric plantar flexion (MIP) and maximal isometric knee extension (MIKE) testing. The data indicate that dancers had a significantly greater rate of force development and peak force during MIP and rate of force development during MIKE in comparison to untrained individuals. Dancers also possessed significantly greater musculo-articular stiffness. Hence, the data provide some evidence that involvement in dance can result in greater muscle force generating capacity and musculo-articular stiffness due to the SSC mechanisms involved in dance movements.

  8. The forces that shape embryos: physical aspects of convergent extension by cell intercalation

    International Nuclear Information System (INIS)

    Keller, Ray; Shook, David; Skoglund, Paul

    2008-01-01

    We discuss the physical aspects of the morphogenic process of convergence (narrowing) and extension (lengthening) of tissues by cell intercalation. These movements, often referred to as 'convergent extension', occur in both epithelial and mesenchymal tissues during embryogenesis and organogenesis of invertebrates and vertebrates, and they play large roles in shaping the body plan during development. Our focus is on the presumptive mesodermal and neural tissues of the Xenopus (frog) embryo, tissues for which some physical measurements have been made. We discuss the physical aspects of how polarized cell motility, oriented along future tissue axes, generate the forces that drive oriented cell intercalation and how this intercalation results in convergence and extension or convergence and thickening of the tissue. Our goal is to identify aspects of these morphogenic movements for further biophysical, molecular and cell biological, and modeling studies

  9. Effects of Second-Order Sum- and Difference-Frequency Wave Forces on the Motion Response of a Tension-Leg Platform Considering the Set-down Motion

    Science.gov (United States)

    Wang, Bin; Tang, Yougang; Li, Yan; Cai, Runbo

    2018-04-01

    This paper presents a study on the motion response of a tension-leg platform (TLP) under first- and second-order wave forces, including the mean-drift force, difference and sum-frequency forces. The second-order wave force is calculated using the full-field quadratic transfer function (QTF). The coupled effect of the horizontal motions, such as surge, sway and yaw motions, and the set-down motion are taken into consideration by the nonlinear restoring matrix. The time-domain analysis with 50-yr random sea state is performed. A comparison of the results of different case studies is made to assess the influence of second-order wave force on the motions of the platform. The analysis shows that the second-order wave force has a major impact on motions of the TLP. The second-order difference-frequency wave force has an obvious influence on the low-frequency motions of surge and sway, and also will induce a large set-down motion which is an important part of heave motion. Besides, the second-order sum-frequency force will induce a set of high-frequency motions of roll and pitch. However, little influence of second-order wave force is found on the yaw motion.

  10. Greater Hip Extension but Not Hip Abduction Explosive Strength Is Associated With Lesser Hip Adduction and Knee Valgus Motion During a Single-Leg Jump-Cut.

    Science.gov (United States)

    Cronin, Baker; Johnson, Samuel T; Chang, Eunwook; Pollard, Christine D; Norcross, Marc F

    2016-04-01

    The relationships between hip abductor and extensor strength and frontal plane hip and knee motions that are associated with anterior cruciate ligament injury risk are equivocal. However, previous research on these relationships has evaluated relatively low-level movement tasks and peak torque rather than a time-critical strength measure such as the rate of torque development (RTD). Females with greater hip abduction and extension RTD would exhibit lesser frontal plane hip and knee motion during a single-leg jump-cutting task. Descriptive laboratory study. Forty recreationally active females performed maximal isometric contractions and single-leg jump-cuts. From recorded torque data, hip extension and abduction RTD was calculated from torque onset to 200 ms after onset. Three-dimensional motion analysis was used to quantify frontal plane hip and knee kinematics during the movement task. For each RTD measure, jump-cut biomechanics were compared between participants in the highest (high) and lowest (low) RTD tertiles. No differences in frontal plane hip and knee kinematics were identified between high and low hip abduction RTD groups. However, those in the high hip extension RTD group exhibited lower hip adduction (high, 3.8° ± 3.0°; low, 6.5° ± 3.0°; P = .019) and knee valgus (high, -2.5° ± 2.3°; low, -4.4° ± 3.2°; P = .046) displacements during the jump-cut. In movements such as cutting that are performed with the hip in a relatively abducted and flexed position, the ability of the gluteus medius to control hip adduction may be compromised. However, the gluteus maximus, functioning as a hip abductor, may take on a pivotal role in controlling hip adduction and knee valgus motion during these types of tasks. Training with a specific emphasis on increasing explosive strength of the hip extensors may be a means through which to improve frontal plane hip and knee control during high-risk maneuvers such as cutting.

  11. Dynamic elastic response prostheses alter approach angles and ground reaction forces but not leg stiffness during a start-stop task.

    Science.gov (United States)

    Haber, Cassandra Kay; Ritchie, Laura J; Strike, Siobhan C

    2018-04-01

    In a dynamic elastic response prosthesis (DERP), spring-like properties aim to replace the loss of musculature and soft tissues and optimise dynamic movement biomechanics, yet higher intact limb (IL) loading exists. It is unknown how amputees wearing a DERP will perform in start-stop movements and how altering the prosthetic stiffness will influence the performance and loading. This study assessed movement dynamics through comparisons in spatiotemporal, kinematic and kinetic variables and leg stiffness of intact, prosthetic and control limbs. The effect of prosthetic stiffness on movement dynamics was also determined. Eleven male unilateral transtibial amputees performed a start-stop task with one DERP set at two different stiffness - Prescribed and Stiffer. Eleven control participants performed the movement with the dominant limb. Kinematic and kinetic data were collected by a twelve-camera motion capture system synchronised with a Kistler force platform. Selected variables were compared between intact, prosthetic and control limbs, and against prosthetic stiffness using ANOVA and effect size. Pearson's Correlation was used to analyse relationship between leg stiffness and prosthetic deflection. Amputees showed a more horizontal approach to the bound during the start-stop movement, with lower horizontal velocities and a longer stance time on the IL compared to controls. In both stiffness conditions, the IL showed selected higher anteroposterior and vertical forces and impulses when compared to the controls. Leg stiffness was not significantly different between limbs as a result of the interplay between angle swept and magnitude of force, even with the change in prosthetic stiffness. A main effect for prosthetic stiffness was found only in higher impact forces of the prosthetic limb and more horizontal touchdown angles of the IL when using the prescribed DERP. In conclusion, amputees achieve the movement with a horizontal approach when compared to controls which

  12. Nuclear Weapons: DOD Assessed the Need for Each Leg of the Strategic Triad and Considered Other Reductions to Nuclear Forces

    Science.gov (United States)

    2016-09-01

    NUCLEAR WEAPONS DOD Assessed the Need for Each Leg of the Strategic Triad and Considered Other Reductions to...Government Accountability Office Highlights of GAO-16-740, a report to congressional requesters September 2016 NUCLEAR WEAPONS DOD Assessed...Since the 1960s, the United States has deployed nuclear weapons on three types of strategic delivery vehicles collectively known as the strategic

  13. Effect of excluded volume on the force-extension of wormlike chains in slit confinement

    Science.gov (United States)

    Li, Xiaolan; Dorfman, Kevin

    We will present a quantitative phase diagram for the stretching of a wormlike chain confined in a slit with excluded volume interactions. Using pruned-enriched Rosenbluth method (PERM) simulations, we demonstrate the existence of a ``confined Pincus'' regime in slit confinement. This regime is similar to the Pincus regime in free solution, where excluded volume effects are sensible. The lower bound for the confined Pincus regime in the force-contour length plane and the dependence of the extension with force and slit size are in agreement with scaling theory. The upper bound of the confined Pincus regime depends on the confinement strength; it ends in strong confinement when the Pincus blobs do not have excluded volume, while it ends in weak confinement when the Pincus blobs do not fit in the slit. We also show the existence of a free-solution Pincus regime in weak confinement that exists before ideal chain behavior sets in under strong forces. We will discuss the implication of our results on the analysis of experiments on the ``tug-of-war'' stretching of DNA partially confined to a slit.

  14. Minimal detectable change of knee extension force measurements obtained by handheld dynamometry from older patients in 2 settings.

    Science.gov (United States)

    Bohannon, Richard W

    2012-01-01

    The measurement properties of handheld dynamometry (HHD) have been studied extensively, but information about the responsiveness of the procedure is scant. The purpose of this study, therefore, was to determine the responsiveness (minimal detectable change [MDC]) for measurements of knee extension force obtained by HHD from older adult patients in 2 different settings. This study involved the retrospective retrieval of knee extension force data of the left and right sides from 2 sources (acute rehabilitation [n = 53] and home care [n = 46]). The standard deviation of the forces and the weighted mean intraclass correlation coefficient (ICC) from 3 previous studies (ICC = 0.90) were then used to calculate the MDC95%. The MDC95% ranged from 46.0 to 79.0 N. It was lower for patients measured in a home care setting than for those measured in an acute rehabilitation setting. By describing the MDC for knee extension force obtained by HHD from older adults in 2 settings, this study provides an indication of the changes in force that would have to be surpassed to conclude that a real change in knee extension strength was observed. The MDCs reported have a role in the interpretation of repeated measurements and in setting goals for changes in knee extension force.

  15. Scaling of the Spring in the Leg during Bouncing Gaits of Mammals

    Science.gov (United States)

    Lee, David V.; Isaacs, Michael R.; Higgins, Trevor E.; Biewener, Andrew A.; McGowan, Craig P.

    2014-01-01

    Trotting, bipedal running, and especially hopping have long been considered the principal bouncing gaits of legged animals. We use the radial-leg spring constant krad to quantify the stiffness of the physical leg during bouncing gaits. The radial-leg is modeled as an extensible strut between the hip and the ground and krad is determined from the force and deflection of this strut in each instance of stance. A Hookean spring is modeled in-series with a linear actuator and the stiffness of this spring krad is determined by minimizing the work of the actuator while reproducing the measured force-deflection dynamics of an individual leg during trotting or running, and of the paired legs during hopping. Prior studies have estimated leg stiffness using kleg, a metric that imagines a virtual-leg connected to the center of mass. While kleg has been applied extensively in human and comparative biomechanics, we show that krad more accurately models the spring in the leg when actuation is allowed, as is the case in biological and robotic systems. Our allometric analysis of krad in the kangaroo rat, tammar wallaby, dog, goat, and human during hopping, trotting, or running show that krad scales as body mass to the two-third power, which is consistent with the predictions of dynamic similarity and with the scaling of kleg. Hence, two-third scaling of locomotor spring constants among mammals is supported by both the radial-leg and virtual-leg models, yet the scaling of krad emerges from work-minimization in the radial-leg model instead of being a defacto result of the ratio of force to length used to compute kleg. Another key distinction between the virtual-leg and radial-leg is that krad is substantially greater than kleg, as indicated by a 30–37% greater scaling coefficient for krad. We also show that the legs of goats are on average twice as stiff as those of dogs of the same mass and that goats increase the stiffness of their legs, in part, by more nearly aligning their

  16. Properties of Force Output and Spectral EMG in Young Patients with Nonspecific Low Back Pain during Isometric Trunk Extension

    OpenAIRE

    Miura, Tatsuhiro; Sakuraba, Keishoku

    2014-01-01

    [Purpose] To clarify the influence of nonspecific low back pain (NSLBP) on force fluctuation and the myoelectric data of back muscles during isometric trunk extension at low to high force levels. [Subjects] Fourteen male subjects with NSLBP and 14 healthy male control subjects participated in this study. [Methods] All participants extended their trunk isometrically maintaining 10 levels of target force [2, 5, 10, 15, 20, 30, 50, 70, 80 and 90% of maximal voluntary contraction (MVC) in a rando...

  17. Effect of body mass index and fat mass on balance force platform measurements during a one-legged stance in older adults.

    Science.gov (United States)

    Pereira, Camila; Silva, Rubens A da; de Oliveira, Marcio R; Souza, Rejane D N; Borges, Renata J; Vieira, Edgar R

    2017-07-05

    The purpose of this study was to evaluate the impact of body mass index (BMI) and fat mass on balance force platform measurements in older adults. The sample consisted of 257 participants who were stratified into four groups by BMI: low weight, normal weight, pre-obesity and obesity. For fat mass variables, older individuals were classified into low and high-fat mass. All groups investigated performed three trials of one-legged stance balance on a force platform. Center of pressure (COP) domain parameters were computed from the mean across trials. Analysis of variance results revealed no significant interactions for groups and sexes for all COP parameters. Comparable balance results were found for BMI and fat groups for all COP parameters. A statistical effect (P COP parameters, regardless of BMI and fat mass variables. Overall, women presented better balance than men. In conclusion, BMI and fat mass do not seem to influence the balance of older adults during a one-leg stance task.

  18. Fractional-order active fault-tolerant force-position controller design for the legged robots using saturated actuator with unknown bias and gain degradation

    Science.gov (United States)

    Farid, Yousef; Majd, Vahid Johari; Ehsani-Seresht, Abbas

    2018-05-01

    In this paper, a novel fault accommodation strategy is proposed for the legged robots subject to the actuator faults including actuation bias and effective gain degradation as well as the actuator saturation. First, the combined dynamics of two coupled subsystems consisting of the dynamics of the legs subsystem and the body subsystem are developed. Then, the interaction of the robot with the environment is formulated as the contact force optimization problem with equality and inequality constraints. The desired force is obtained by a dynamic model. A robust super twisting fault estimator is proposed to precisely estimate the defective torque amplitude of the faulty actuator in finite time. Defining a novel fractional sliding surface, a fractional nonsingular terminal sliding mode control law is developed. Moreover, by introducing a suitable auxiliary system and using its state vector in the designed controller, the proposed fault-tolerant control (FTC) scheme guarantees the finite-time stability of the closed-loop control system. The robustness and finite-time convergence of the proposed control law is established using the Lyapunov stability theory. Finally, numerical simulations are performed on a quadruped robot to demonstrate the stable walking of the robot with and without actuator faults, and actuator saturation constraints, and the results are compared to results with an integer order fault-tolerant controller.

  19. The use of forced flexion/extension views in the obtunded trauma patient

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, Harry J.; Wagner, Jason; Anglen, Jeff; Bunn, Paul; Metzler, Michael [Department of Radiology, Departments of Radiology/Orthopaedics and Surgery, University of Missouri-Columbia, One Hospital Drive - DC069.10, Columbia, MO 65212 (United States)

    2002-10-01

    To determine whether forced flexion/extension (F/E) films for ''clearing'' the cervical spine in unconscious or semiconscious patients are useful or actually dangerous.Design and patients. Of 810 patients admitted for blunt trauma over a 5-year period, 479 patients whose films and charts were available received passive F/E film views of the cervical spine. Of these, 447 were reviewed retrospectively in masked fashion for any exacerbation of neurological changes subsequent to the procedure and with respect to the final neurological status at discharge.Results. Twenty-nine patients (6%) had various abnormalities including fractures and ligamentous injuries seen on the initial films. Following forced F/E films no change was made in the diagnosis of 23 patients. Of the remaining six patients, two required no treatment, two only required the use of a collar but two did have surgical intervention, this decision being based on the findings seen in the initial films. However, 285 films (59%) were judged inadequate due either to inadequate F/E (150 patients, 31%) or poor visualization (194 patients, 40%). There were three false positives all subsequently cleared by other studies and there were no false negatives. From the chart review, there were no complications or deaths attributable to the procedure.Conclusion. Although we were unable to find any complication or deaths directly attributable to the procedure, the clinicians abandoned passive F/E views in obtunded patients on the grounds of expense. Our present method of ''clearing'' a cervical spine in an obtunded patient is a cross-table lateral radiograph followed by a high-resolution thin-slice CT scan with sagittal and coronal reconstruction. We are against the use of routine MRI studies and of a forced F/E view in these patients. (orig.)

  20. The use of forced flexion/extension views in the obtunded trauma patient

    International Nuclear Information System (INIS)

    Griffiths, Harry J.; Wagner, Jason; Anglen, Jeff; Bunn, Paul; Metzler, Michael

    2002-01-01

    To determine whether forced flexion/extension (F/E) films for ''clearing'' the cervical spine in unconscious or semiconscious patients are useful or actually dangerous.Design and patients. Of 810 patients admitted for blunt trauma over a 5-year period, 479 patients whose films and charts were available received passive F/E film views of the cervical spine. Of these, 447 were reviewed retrospectively in masked fashion for any exacerbation of neurological changes subsequent to the procedure and with respect to the final neurological status at discharge.Results. Twenty-nine patients (6%) had various abnormalities including fractures and ligamentous injuries seen on the initial films. Following forced F/E films no change was made in the diagnosis of 23 patients. Of the remaining six patients, two required no treatment, two only required the use of a collar but two did have surgical intervention, this decision being based on the findings seen in the initial films. However, 285 films (59%) were judged inadequate due either to inadequate F/E (150 patients, 31%) or poor visualization (194 patients, 40%). There were three false positives all subsequently cleared by other studies and there were no false negatives. From the chart review, there were no complications or deaths attributable to the procedure.Conclusion. Although we were unable to find any complication or deaths directly attributable to the procedure, the clinicians abandoned passive F/E views in obtunded patients on the grounds of expense. Our present method of ''clearing'' a cervical spine in an obtunded patient is a cross-table lateral radiograph followed by a high-resolution thin-slice CT scan with sagittal and coronal reconstruction. We are against the use of routine MRI studies and of a forced F/E view in these patients. (orig.)

  1. Properties of Force Output and Spectral EMG in Young Patients with Nonspecific Low Back Pain during Isometric Trunk Extension.

    Science.gov (United States)

    Miura, Tatsuhiro; Sakuraba, Keishoku

    2014-03-01

    [Purpose] To clarify the influence of nonspecific low back pain (NSLBP) on force fluctuation and the myoelectric data of back muscles during isometric trunk extension at low to high force levels. [Subjects] Fourteen male subjects with NSLBP and 14 healthy male control subjects participated in this study. [Methods] All participants extended their trunk isometrically maintaining 10 levels of target force [2, 5, 10, 15, 20, 30, 50, 70, 80 and 90% of maximal voluntary contraction (MVC) in a random order] for about 4 seconds with visual feedback. A force transducer and tri-axis force sensor were positioned at the 7th thoracic vertebra to measure force output and the direction of force. Myoelectric activities of the back muscles (longissimus thoracis, L2 level; multifidus, S1 level) were recorded by surface electromyography. [Results] Force output of NSLBP subjects fluctuated more than that of healthy subjects at 30% and 50%MVC. Higher median power frequency in the multifidus was observed in NSLBP subjects at moderate to high force levels. [Conclusion] These results show that the properties of force output in NSLBP subjects differ from those in healthy subjects, suggesting that the assessment of force fluctuation of back muscles at moderate force levels is a useful index for evaluating and discriminating NSLBP.

  2. Producing a Data Dictionary from an Extensible Markup Language (XML) Schemain the Global Force Management Data Initiative

    Science.gov (United States)

    2017-02-01

    Management Data Initiative by Frederick S Brundick Approved for public release; distribution is unlimited. NOTICES Disclaimers The findings in this report...Schema in the Global Force Management Data Initiative by Frederick S Brundick Computing and Information Sciences Directorate, ARL Approved for public...Technical Report Producing a Data Dictionary from an Extensible Markup Language (XML) Schema in the Global Force Management Data Initiative Frederick S

  3. A comparison of one-legged and two-legged countermovement jumps

    NARCIS (Netherlands)

    van Soest, A J; Roebroeck, M.E.; Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    1985-01-01

    Ten well-trained male volleyball players performed one-legged and two-legged vertical countermovement jumps. Ground reaction forces, cinematographic data, and electromyographic data were recorded. Jumping height in one-legged jumps was 58.5% of that reached in two-legged jumps. Mean net torques in

  4. Leg Swelling

    Science.gov (United States)

    ... ed. New York, N.Y.: The McGraw Hill Companies; 2016. http://www.accessmedicine.com. Accessed Dec. 31, ... http://www.mayoclinic.org/symptoms/leg-swelling/basics/definition/SYM-20050910 . Mayo Clinic Footer Legal Conditions and ...

  5. Effects of knee extension constraint training on knee flexion angle and peak impact ground-reaction force.

    Science.gov (United States)

    Liu, Hui; Wu, Will; Yao, Wanxiang; Spang, Jeffrey T; Creighton, R Alexander; Garrett, William E; Yu, Bing

    2014-04-01

    Low compliance with training programs is likely to be one of the major reasons for inconsistency of the data regarding the effectiveness of current anterior cruciate ligament (ACL) injury prevention programs. Training methods that reduce training time and cost could favorably influence the effectiveness of ACL injury prevention programs. A newly designed knee extension constraint training device may serve this purpose. (1) Knee extension constraint training for 4 weeks would significantly increase the knee flexion angle at the time of peak impact posterior ground-reaction force and decrease peak impact ground-reaction forces during landing of a stop-jump task and a side-cutting task, and (2) the training effects would be retained 4 weeks after completion of the training program. Controlled laboratory study. Twenty-four recreational athletes were randomly assigned to group A or B. Participants in group A played sports without wearing a knee extension constraint device for 4 weeks and then played sports while wearing the device for 4 weeks, while participants in group B underwent a reversed protocol. Both groups were tested at the beginning of week 1 and at the ends of weeks 4 and 8 without wearing the device. Knee joint angles were obtained from 3-dimensional videographic data, while ground-reaction forces were measured simultaneously using force plates. Analyses of variance were performed to determine the training effects and the retention of training effects. Participants in group A significantly increased knee flexion angles and decreased ground-reaction forces at the end of week 8 (P ≤ .012). Participants in group B significantly increased knee flexion angles and decreased ground-reaction forces at the ends of weeks 4 and 8 (P ≤ .007). However, participants in group B decreased knee flexion angles and increased ground-reaction forces at the end of week 8 in comparison with the end of week 4 (P ≤ .009). Knee extension constraint training for 4 weeks

  6. Leg extension power is a pre-disaster modifiable risk factor for post-traumatic stress disorder among survivors of the Great East Japan Earthquake: a retrospective cohort study.

    Science.gov (United States)

    Momma, Haruki; Niu, Kaijun; Kobayashi, Yoritoshi; Huang, Cong; Otomo, Atsushi; Chujo, Masahiko; Tadaura, Hiroko; Nagatomi, Ryoichi

    2014-01-01

    Post-traumatic stress disorder (PTSD) is a common psychological problem following natural disasters. Although pre-disaster risk factors are important for early detection and proactive support, the examination of such has been limited to sociodemographic factors, which were largely unaffected by the disasters. We examined the association between pre-disaster physical functioning and lifestyle and PTSD symptoms five months after the earthquake in the Great East Japan Earthquake survivors who were participating in a pre-existing cohort study. We designed a retrospective cohort study of a cooperative association in Sendai from August 2010 to August 2011. In 2010, lifestyle, physical condition, and sociodemographic factors were examined by self-reported questionnaires completed by 522 employees of this organization. We also measured the leg extension power of all the participants. PTSD symptoms were evaluated by the Japanese version of the Impact of Event Scale-Revised (IES-R-J) following the earthquake of 2011. In multivariate linear regression analysis, leg extension power (β = -0.128, P = 0.025), daily drinking (β  = 0.203, P = 0.006), and depressive symptoms (β  = 0.139, P = 0.008) were associated with total score of the IES-R-J among men. Moreover, for the IES-R-J subscale, leg extension power was also negatively associated with Intrusion (β = -0.114, P = 0.045) and Hyperarousal (β = -0.163, P = 0.004) after adjusting for all other significant variables. For women, hypertension (β  = 0.226, P = 0.032) and depressive symptoms (β  = 0.205, P = 0.046) were associated with the total score of the IES-R-J. Leg extension power is a potentially modifiable pre-disaster risk factor among men for attenuating the severity of PTSD symptoms associated with great disasters such as the Great East Japan Earthquake among men.

  7. Leg extension power is a pre-disaster modifiable risk factor for post-traumatic stress disorder among survivors of the Great East Japan Earthquake: a retrospective cohort study.

    Directory of Open Access Journals (Sweden)

    Haruki Momma

    Full Text Available BACKGROUND: Post-traumatic stress disorder (PTSD is a common psychological problem following natural disasters. Although pre-disaster risk factors are important for early detection and proactive support, the examination of such has been limited to sociodemographic factors, which were largely unaffected by the disasters. We examined the association between pre-disaster physical functioning and lifestyle and PTSD symptoms five months after the earthquake in the Great East Japan Earthquake survivors who were participating in a pre-existing cohort study. METHODS: We designed a retrospective cohort study of a cooperative association in Sendai from August 2010 to August 2011. In 2010, lifestyle, physical condition, and sociodemographic factors were examined by self-reported questionnaires completed by 522 employees of this organization. We also measured the leg extension power of all the participants. PTSD symptoms were evaluated by the Japanese version of the Impact of Event Scale-Revised (IES-R-J following the earthquake of 2011. RESULTS: In multivariate linear regression analysis, leg extension power (β = -0.128, P = 0.025, daily drinking (β  = 0.203, P = 0.006, and depressive symptoms (β  = 0.139, P = 0.008 were associated with total score of the IES-R-J among men. Moreover, for the IES-R-J subscale, leg extension power was also negatively associated with Intrusion (β = -0.114, P = 0.045 and Hyperarousal (β = -0.163, P = 0.004 after adjusting for all other significant variables. For women, hypertension (β  = 0.226, P = 0.032 and depressive symptoms (β  = 0.205, P = 0.046 were associated with the total score of the IES-R-J. CONCLUSIONS: Leg extension power is a potentially modifiable pre-disaster risk factor among men for attenuating the severity of PTSD symptoms associated with great disasters such as the Great East Japan Earthquake among men.

  8. Cortical activity differs between position- and force-control knee extension tasks.

    Science.gov (United States)

    Poortvliet, Peter C; Tucker, Kylie J; Finnigan, Simon; Scott, Dion; Sowman, Paul; Hodges, Paul W

    2015-12-01

    Neural control differs between position- and force-control tasks as evident from divergent effects of fatigue and pain. Unlike force-control tasks, position-control tasks focus on a postural goal to maintain a joint angle. Cortical involvement is suggested to be less during postural control, but whether this differs between position- and force-control paradigms remains unclear. Coherence estimates the functional communication between spatially distinct active regions within the cortex (cortico-cortical coherence; CCC) and between the cortex and muscles (corticomuscular coherence; CMC). We investigated whether cortical involvement differed between force-control and more posturally focused, position-control tasks. Seventeen adults performed position- and force-control knee extensor efforts at a submaximal load (10 % maximum voluntary contraction). Surface electromyography was recorded from the right knee extensor and flexor muscles and brain activity using electroencephalography (EEG). CCC and CMC in the beta (13-30 Hz) and gamma (30-45 Hz) frequency bands were calculated between combinations of intra- and inter-hemispheric pairs of electrodes, and between four EEG electrodes that approximated the left motor cortical area, and right knee extensor EMG, respectively. Differences in EEG power and muscle activity were also calculated. CCC was greater across distributed regions in the force-control task. Beta EEG power in the left hemisphere was higher for the position-control task. Although averaged CMC data differed between tasks, there was no task difference for individual CMC data. Muscle activity and force did not differ between tasks. The results demonstrate differential cortical contributions to control force- versus position-control tasks. This might contribute to differences in performance outcomes of these tasks that have been shown previously.

  9. An analysis of the extension of a ZnO piezoelectric semiconductor nanofiber under an axial force

    Science.gov (United States)

    Zhang, Chunli; Wang, Xiaoyuan; Chen, Weiqiu; Yang, Jiashi

    2017-02-01

    This paper presents a theoretical analysis on the axial extension of an n-type ZnO piezoelectric semiconductor nanofiber under an axial force. The phenomenological theory of piezoelectric semiconductors consisting of Newton’s second law of motion, the charge equation of electrostatics and the conservation of charge was used. The equations were linearized for small axial force and hence small electron concentration perturbation, and were reduced to one-dimensional equations for thin fibers. Simple and analytical expressions for the electromechanical fields and electron concentration in the fiber were obtained. The fields are either totally or partially described by hyperbolic functions relatively large near the ends of the fiber and change rapidly there. The behavior of the fields is sensitive to the initial electron concentration and the applied axial force. For higher initial electron concentrations the fields are larger near the ends and change more rapidly there.

  10. Comparison of a laboratory grade force platform with a Nintendo Wii Balance Board on measurement of postural control in single-leg stance balance tasks.

    Science.gov (United States)

    Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; van Dieën, Jaap H

    2013-04-26

    Training and testing of balance have potential applications in sports and medicine. Laboratory grade force plates (FP) are considered the gold standard for the measurement of balance performance. Measurements in these systems are based on the parameterization of center of pressure (CoP) trajectories. Previous research validated the inexpensive, widely available and portable Nintendo Wii Balance Board (WBB). The novelty of the present study is that FP and WBB are compared on CoP data that was collected simultaneously, by placing the WBB on the FP. Fourteen healthy participants performed ten sequences of single-leg stance tasks with eyes open (EO), eyes closed (EC) and after a sideways hop (HOP). Within trial comparison of the two systems showed small root-mean-square differences for the CoP trajectories in the x and y direction during the three tasks (mean±SD; EO: 0.33±0.10 and 0.31±0.16 mm; EC: 0.58±0.17 and 0.63±0.19 mm; HOP: 0.74±0.34 and 0.74±0.27 mm, respectively). Additionally, during all 420 trials, comparison of FP and WBB revealed very high Pearson's correlation coefficients (r) of the CoP trajectories (x: 0.999±0.002; y: 0.998±0.003). A general overestimation was found on the WBB compared to the FP for 'CoP path velocity' (EO: 5.3±1.9%; EC: 4.0±1.4%; HOP: 4.6±1.6%) and 'mean absolute CoP sway' (EO: 3.5±0.7%; EC: 3.7±0.5%; HOP: 3.6±1.0%). This overestimation was highly consistent over the 140 trials per task (r>0.996). The present findings demonstrate that WBB is sufficiently accurate in quantifying CoP trajectory, and overall amplitude and velocity during single-leg stance balance tasks. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. OSU Extension, Ohio Aging Network Join Forces: Creating Resources for Successful Aging

    Science.gov (United States)

    Goard, Linnette Mizer

    2010-01-01

    Ohio State University Extension and Ohio's Aging Network professionals have worked together for more than a decade to address issues of importance to Ohio's older adult population. The team's mission is to provide education, training, and resources to empower older Ohioans to achieve an optimal level of well-being. The Senior Series team initially…

  12. Broken Leg

    Science.gov (United States)

    ... the leg, which can result in a fracture. Stress fractures outside of sport situations are more common in people who have: ... shoes. Choose the appropriate shoe for your favorite sports or activities. And ... can prevent stress fractures. Rotate running with swimming or biking. If ...

  13. Support Leg Loading in Punt Kicking

    Science.gov (United States)

    Kermond, John; Konz, Stephen

    1978-01-01

    Maximum distance in football punt kicking is associated with a maximum force transfer to the ball rather than a maximum force transfer through the ground via the support leg. For maximum distance, tred lightly. (Author)

  14. Tests and indicators for improving the pedagogical control of the legs force of long and middle distance, as well as sport walk 12-15 school categories athletes

    Directory of Open Access Journals (Sweden)

    Ernesto Santana-García

    2014-04-01

    Full Text Available The control of the yield inside the process of sport training is one of the instruments that guarantee that it is made on the base of solid arguments as for the correspondence among the loads or preparation stimuli that must receive the sportsman and its condition to assimilate it. Due to the deficiencies, detected during a preliminary diagnosis based on the content analysis, measurement and mathematical statistical methods that corroborate the necessity to perfect elements of the sportsmen preparation management, a study begins with the in o rde r to give solution to the scientific problem: How to improve the pedagogic control of the legs force on Long and Middle distance, as well as Sport Walk athletes at 12 - 15 yeas school categories from “Ormani Arenado” Initial Sport School of Pinar del Río? It has the objective to select tests and indicators that improve this pedagogic control. There were used different methods and investigation instruments such as, analysis and synthesis, the measurement, as well as the descriptive and inferential statistic, which allowed the selection of the test of the ten jumps to include it in the protocol of evaluation of the physical performance set for the school categories, with procedures that brings forth four indicators on the sportsman's state. Its feasibility is being evaluating at present in an extended study certified by the provincial commission of Athletics. The contributions of this research, favor to the results of the investigative project “The evaluation and planning of the training in Long and Middle distance, as well as Sport Walk athletes in Pinar del Río”, answering, at the same time, to the fourth technological demand of the Athletics in this western county of Cuba.

  15. Night Leg Cramps

    Science.gov (United States)

    Symptoms Night leg cramps By Mayo Clinic Staff Night leg cramps, also called nocturnal leg cramps, are painful, involuntary contractions or spasms of muscles in your legs, usually occurring when you're in bed. Night ...

  16. The definition of necessary axial force for extension of initial borehole for soft soil compaction process design

    Directory of Open Access Journals (Sweden)

    Ter-Martirosyan Zaven

    2016-01-01

    Full Text Available The article provides an analytical solution of the soil pile and surrounding soil cylinder interaction problem, with the possibility of extension of the pile shaft in its construction. Presents a closed solution for determination of radial and tangential stresses in the process of expansion of the pile shaft, as well as the minimum vertical force sufficient for the crushing of the pile material and move it in radial direction to the specified value. The problem is most actual for compacted soil bases with use of piles-drains of sand and sand-gravel mixture.

  17. The Relationship of Static Anthropometric Measurements to Lower Leg, Ankle, and Foot Injuries in Air Force Academy Cadets: A Prospective Longitudinal Study

    National Research Council Canada - National Science Library

    McMahon, Thomas

    2001-01-01

    The purpose of this prospective cohort study was to investigate the relationship between static anthropometric measures or demographical information and overuse injuries in the lower leg, ankle and foot...

  18. Leg-adjustment strategies for stable running in three dimensions

    International Nuclear Information System (INIS)

    Peuker, Frank; Maufroy, Christophe; Seyfarth, André

    2012-01-01

    The dynamics of the center of mass (CoM) in the sagittal plane in humans and animals during running is well described by the spring-loaded inverted pendulum (SLIP). With appropriate parameters, SLIP running patterns are stable, and these models can recover from perturbations without the need for corrective strategies, such as the application of additional forces. Rather, it is sufficient to adjust the leg to a fixed angle relative to the ground. In this work, we consider the extension of the SLIP to three dimensions (3D SLIP) and investigate feed-forward strategies for leg adjustment during the flight phase. As in the SLIP model, the leg is placed at a fixed angle. We extend the scope of possible reference axes from only fixed horizontal and vertical axes to include the CoM velocity vector as a movement-related reference, resulting in six leg-adjustment strategies. Only leg-adjustment strategies that include the CoM velocity vector produced stable running and large parameter domains of stability. The ability of the model to recover from perturbations along the direction of motion (directional stability) depended on the strategy for lateral leg adjustment. Specifically, asymptotic and neutral directional stability was observed for strategies based on the global reference axis and the velocity vector, respectively. Additional features of velocity-based leg adjustment are running at arbitrary low speed (kinetic energy) and the emergence of large domains of stable 3D running that are smoothly transferred to 2D SLIP stability and even to 1D SLIP hopping. One of the additional leg-adjustment strategies represented a large convex region of parameters where stable and robust hopping and running patterns exist. Therefore, this strategy is a promising candidate for implementation into engineering applications, such as robots, for instance. In a preliminary comparison, the model predictions were in good agreement with the experimental data, suggesting that the 3D SLIP is an

  19. Greater Hip Extension but Not Hip Abduction Explosive Strength Is Associated With Lesser Hip Adduction and Knee Valgus Motion During a Single-Leg Jump-Cut

    OpenAIRE

    Cronin, Baker; Johnson, Samuel T.; Chang, Eunwook; Pollard, Christine D.; Norcross, Marc F.

    2016-01-01

    Background: The relationships between hip abductor and extensor strength and frontal plane hip and knee motions that are associated with anterior cruciate ligament injury risk are equivocal. However, previous research on these relationships has evaluated relatively low-level movement tasks and peak torque rather than a time-critical strength measure such as the rate of torque development (RTD). Hypothesis: Females with greater hip abduction and extension RTD would exhibit lesser frontal plane...

  20. Extension of the ReaxFF Combustion Force Field toward Syngas Combustion and Initial Oxidation Kinetics.

    Science.gov (United States)

    Ashraf, Chowdhury; van Duin, Adri C T

    2017-02-09

    A detailed insight of key reactive events related to oxidation and pyrolysis of hydrocarbon fuels further enhances our understanding of combustion chemistry. Though comprehensive kinetic models are available for smaller hydrocarbons (typically C 3 or lower), developing and validating reaction mechanisms for larger hydrocarbons is a daunting task, due to the complexity of their reaction networks. The ReaxFF method provides an attractive computational method to obtain reaction kinetics for complex fuel and fuel mixtures, providing an accuracy approaching ab-initio-based methods but with a significantly lower computational expense. The development of the first ReaxFF combustion force field by Chenoweth et al. (CHO-2008 parameter set) in 2008 has opened new avenues for researchers to investigate combustion chemistry from the atomistic level. In this article, we seek to address two issues with the CHO-2008 ReaxFF description. While the CHO-2008 description has achieved significant popularity for studying large hydrocarbon combustion, it fails to accurately describe the chemistry of small hydrocarbon oxidation, especially conversion of CO 2 from CO, which is highly relevant to syngas combustion. Additionally, the CHO-2008 description was obtained faster than expected H abstraction by O 2 from hydrocarbons, thus underestimating the oxidation initiation temperature. In this study, we seek to systemically improve the CHO-2008 description and validate it for these cases. Additionally, our aim was to retain the accuracy of the 2008 description for larger hydrocarbons and provide similar quality results. Thus, we expanded the ReaxFF CHO-2008 DFT-based training set by including reactions and transition state structures relevant to the syngas and oxidation initiation pathways and retrained the parameters. To validate the quality of our force field, we performed high-temperature NVT-MD simulations to study oxidation and pyrolysis of four different hydrocarbon fuels, namely

  1. Extensive wet episodes in Late Glacial Australia resulting from high-latitude forcings

    Science.gov (United States)

    Bayon, Germain; de Deckker, Patrick; Magee, John W.; Germain, Yoan; Bermell, Sylvain; Tachikawa, Kazuyo; Norman, Marc D.

    2017-03-01

    Millennial-scale cooling events termed Heinrich Stadials punctuated Northern Hemisphere climate during the last glacial period. Latitudinal shifts of the intertropical convergence zone (ITCZ) are thought to have rapidly propagated these abrupt climatic signals southward, influencing the evolution of Southern Hemisphere climates and contributing to major reorganisation of the global ocean-atmosphere system. Here, we use neodymium isotopes from a marine sediment core to reconstruct the hydroclimatic evolution of subtropical Australia between 90 to 20 thousand years ago. We find a strong correlation between our sediment provenance proxy data and records for western Pacific tropical precipitations and Australian palaeolakes, which indicates that Northern Hemisphere cooling phases were accompanied by pronounced excursions of the ITCZ and associated rainfall as far south as about 32°S. Comparatively, however, each of these humid periods lasted substantially longer than the mean duration of Heinrich Stadials, overlapping with subsequent warming phases of the southern high-latitudes recorded in Antarctic ice cores. In addition to ITCZ-driven hydroclimate forcing, we infer that changes in Southern Ocean climate also played an important role in regulating late glacial atmospheric patterns of the Southern Hemisphere subtropical regions.

  2. Scaling of the spring in the leg during bouncing gaits of mammals.

    Science.gov (United States)

    Lee, David V; Isaacs, Michael R; Higgins, Trevor E; Biewener, Andrew A; McGowan, Craig P

    2014-12-01

    Trotting, bipedal running, and especially hopping have long been considered the principal bouncing gaits of legged animals. We use the radial-leg spring constant [Formula: see text] to quantify the stiffness of the physical leg during bouncing gaits. The radial-leg is modeled as an extensible strut between the hip and the ground and [Formula: see text] is determined from the force and deflection of this strut in each instance of stance. A Hookean spring is modeled in-series with a linear actuator and the stiffness of this spring [Formula: see text] is determined by minimizing the work of the actuator while reproducing the measured force-deflection dynamics of an individual leg during trotting or running, and of the paired legs during hopping. Prior studies have estimated leg stiffness using [Formula: see text], a metric that imagines a virtual-leg connected to the center of mass. While [Formula: see text] has been applied extensively in human and comparative biomechanics, we show that [Formula: see text] more accurately models the spring in the leg when actuation is allowed, as is the case in biological and robotic systems. Our allometric analysis of [Formula: see text] in the kangaroo rat, tammar wallaby, dog, goat, and human during hopping, trotting, or running show that [Formula: see text] scales as body mass to the two-third power, which is consistent with the predictions of dynamic similarity and with the scaling of [Formula: see text]. Hence, two-third scaling of locomotor spring constants among mammals is supported by both the radial-leg and virtual-leg models, yet the scaling of [Formula: see text] emerges from work-minimization in the radial-leg model instead of being a defacto result of the ratio of force to length used to compute [Formula: see text]. Another key distinction between the virtual-leg and radial-leg is that [Formula: see text] is substantially greater than [Formula: see text], as indicated by a 30-37% greater scaling coefficient for [Formula

  3. Loading and performance of the support leg in kicking.

    Science.gov (United States)

    Ball, Kevin

    2013-09-01

    The punt kick is important in many football codes and support leg kinematics and ground reaction forces have been implicated in injury and performance in kicking. To evaluate ground reaction forces and support leg kinematics in the punt kick. Cross sectional study. Seven elite Australian football players performed maximal kicks into a net using both the preferred and non-preferred legs. A force plate measured ground reaction forces and an optical motion capture system (200Hz) collected kinematic data during the stance phase of the kick. Preferred and non-preferred legs were compared and performance was evaluated by correlating parameters with foot speed at ball contact. Vertical forces were larger than running at a similar speed but did not reach levels that might be considered an injury risk. Braking forces were directed solely posteriorly, as for soccer kicks, but lateral force patterns varied with some players experiencing greater forces medially and others laterally. A more extended support leg, larger peak vertical and braking force during the stance phase and a shorter stance contact time was associated with larger kick leg foot speed at ball contact. No difference existed between the preferred and non-preferred legs for ground reaction forces or support leg mechanics. To punt kick longer, a straighter support leg, less time on the ground and stronger braking should be encouraged. Conditioning the support leg to provide stronger braking potential is recommended. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  4. Time series of ground reaction forces following a single leg drop jump landing in elite youth soccer players consist of four distinct phases

    NARCIS (Netherlands)

    Fransz, Duncan P.; Huurnink, Arnold; de Boode, Vosse A.; Kingma, Idsart; van Dieën, Jaap H.

    2016-01-01

    The single leg drop jump landing test may assess dynamic and static balance abilities in different phases of the landing. However objective definitions of different phases following landing and associated reliability are lacking. Therefore, we determined the existence of possible distinct phases of

  5. Running with a load increases leg stiffness.

    Science.gov (United States)

    Silder, Amy; Besier, Thor; Delp, Scott L

    2015-04-13

    Spring-mass models have been used to characterize running mechanics and leg stiffness in a variety of conditions, yet it remains unknown how running while carrying a load affects running mechanics and leg stiffness. The purpose of this study was to test the hypothesis that running with a load increases leg stiffness. Twenty-seven subjects ran at a constant speed on a force-measuring treadmill while carrying no load, and while wearing weight vests loaded with 10%, 20%, and 30% of body weight. We measured lower extremity motion and created a scaled musculoskeletal model of each subject, which we used to estimate lower extremity joint angles and leg length. We estimated dimensionless leg stiffness as the ratio of the peak vertical ground reaction force (normalized to body weight) and the change in stance phase leg length (normalized to leg length at initial foot contact). Leg length was calculated as the distance from the center of the pelvis to the center-of-pressure under the foot. We found that dimensionless leg stiffness increased when running with load (p=0.001); this resulted from an increase in the peak vertical ground reaction force (pleg length (p=0.025). When running with load, subjects had longer ground contact times (pleg stiffness to accommodate an added load. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Leg Injuries and Disorders

    Science.gov (United States)

    Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion ... falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint ...

  7. Peripheral artery disease - legs

    Science.gov (United States)

    Peripheral vascular disease; PVD; PAD; Arteriosclerosis obliterans; Blockage of leg arteries; Claudication; Intermittent claudication; Vaso-occlusive disease of the legs; Arterial insufficiency of ...

  8. Effect of telescopic distal extension removable partial dentures on oral health related quality of life and maximum bite force: A preliminary cross over study.

    Science.gov (United States)

    Elsyad, Moustafa Abdou; Mostafa, Aisha Zakaria

    2018-01-01

    This cross over study aimed to evaluate the effect of telescopic distal extension removable partial dentures on oral health related quality of life and maximum bite force MATERIALS AND METHODS: Twenty patients with complete maxillary edentulism and partially edentulous mandibles with anterior teeth only remaining were selected for this cross over study. All patients received complete maxillary dentures and mandibular partial removable dental prosthesis (PRDP, control). After 3 months of adaptation, PRDP was replaced with conventional telescopic partial dentures (TPD) or telescopic partial dentures with cantilevered extensions (TCPD) in a quasi-random method. Oral health related quality of life (OHRQoL) was measured using OHIP-14 questionnaire and Maximum bite force (MBF) was measured using a bite force transducer. Measurements were performed 3 months after using each of the following prostheses; PRDP, TPD, and TCPD. TCPD showed the OHIP-14 lowest scores (i.e., the highest patient satisfaction with their OHRQoL), followed by TPD, and PRDP showed the highest OHIP-14 scores (i.e., the lowest patient satisfaction with OHRQoL). TCPD showed the highest MBF (70.7 ± 3.71), followed by TPD (57.4 ± 3.43) and the lowest MBF (40.2 ± 2.20) was noted with PRDP. WITHIN The Limitations of This Study, Mandibular Telescopic Distal Extension Removable Partial Dentures with Cantilevered Extensions Were Associated with Improved Oral Health Related Quality of Life and Maximum Bite Force Compared to Telescopic or Conventional PRDP. Telescopic distal extension removable prostheses is an esthetic restoration in partially edentulous patients with free end saddle. This article describes the addition of cantilevered extensions of this prosthesis. The results showed that telescopic distal extension removable prostheses with cantilevered extensions were associated with improved oral health related quality of life and maximum bite force compared to telescopic or conventional RPDs

  9. Force

    CERN Document Server

    Graybill, George

    2007-01-01

    Forces are at work all around us. Discover what a force is, and different kinds of forces that work on contact and at a distance. We use simple language and vocabulary to make this invisible world easy for students to ""see"" and understand. Examine how forces ""add up"" to create the total force on an object, and reinforce concepts and extend learning with sample problems.

  10. Estimations of One Repetition Maximum and Isometric Peak Torque in Knee Extension Based on the Relationship Between Force and Velocity.

    Science.gov (United States)

    Sugiura, Yoshito; Hatanaka, Yasuhiko; Arai, Tomoaki; Sakurai, Hiroaki; Kanada, Yoshikiyo

    2016-04-01

    We aimed to investigate whether a linear regression formula based on the relationship between joint torque and angular velocity measured using a high-speed video camera and image measurement software is effective for estimating 1 repetition maximum (1RM) and isometric peak torque in knee extension. Subjects comprised 20 healthy men (mean ± SD; age, 27.4 ± 4.9 years; height, 170.3 ± 4.4 cm; and body weight, 66.1 ± 10.9 kg). The exercise load ranged from 40% to 150% 1RM. Peak angular velocity (PAV) and peak torque were used to estimate 1RM and isometric peak torque. To elucidate the relationship between force and velocity in knee extension, the relationship between the relative proportion of 1RM (% 1RM) and PAV was examined using simple regression analysis. The concordance rate between the estimated value and actual measurement of 1RM and isometric peak torque was examined using intraclass correlation coefficients (ICCs). Reliability of the regression line of PAV and % 1RM was 0.95. The concordance rate between the actual measurement and estimated value of 1RM resulted in an ICC(2,1) of 0.93 and that of isometric peak torque had an ICC(2,1) of 0.87 and 0.86 for 6 and 3 levels of load, respectively. Our method for estimating 1RM was effective for decreasing the measurement time and reducing patients' burden. Additionally, isometric peak torque can be estimated using 3 levels of load, as we obtained the same results as those reported previously. We plan to expand the range of subjects and examine the generalizability of our results.

  11. Guidelines for the first-line treatment of restless legs syndrome/Willis-Ekbom disease, prevention and treatment of dopaminergic augmentation: a combined task force of the IRLSSG, EURLSSG, and the RLS-foundation.

    Science.gov (United States)

    Garcia-Borreguero, Diego; Silber, Michael H; Winkelman, John W; Högl, Birgit; Bainbridge, Jacquelyn; Buchfuhrer, Mark; Hadjigeorgiou, Georgios; Inoue, Yuichi; Manconi, Mauro; Oertel, Wolfgang; Ondo, William; Winkelmann, Juliane; Allen, Richard P

    2016-05-01

    A Task Force was established by the International Restless Legs Syndrome Study Group (IRLSSG) in conjunction with the European Restless Legs Syndrome Study Group (EURLSSG) and the RLS Foundation (RLS-F) to develop evidence-based and consensus-based recommendations for the prevention and treatment of long-term pharmacologic treatment of dopaminergic-induced augmentation in restless legs syndrome/Willis-Ekbom disease (RLS/WED). The Task Force made the following prevention and treatment recommendations: As a means to prevent augmentation, medications such as α2δ ligands may be considered for initial RLS/WED treatment; these drugs are effective and have little risk of augmentation. Alternatively, if dopaminergic drugs are elected as initial treatment, then the daily dose should be as low as possible and not exceed that recommended for RLS/WED treatment. However, the physician should be aware that even low dose dopaminergics can cause augmentation. Patients with low iron stores should be given appropriate iron supplementation. Daily treatment by either medication should start only when symptoms have a significant impact on quality of life in terms of frequency and severity; intermittent treatment might be considered in intermediate cases. Treatment of existing augmentation should be initiated, where possible, with the elimination/correction of extrinsic exacerbating factors (iron levels, antidepressants, antihistamines, etc.). In cases of mild augmentation, dopamine agonist therapy can be continued by dividing or advancing the dose, or increasing the dose if there are breakthrough night-time symptoms. Alternatively, the patient can be switched to an α2δ ligand or rotigotine. For severe augmentation the patient can be switched either to an α2δ ligand or rotigotine, noting that rotigotine may also produce augmentation at higher doses with long-term use. In more severe cases of augmentation an opioid may be considered, bypassing α2δ ligands and rotigotine

  12. Déficit bilateral nos movimentos de flexão e extensão de perna e flexão do cotovelo Déficit bilateral en los movimientos de flexion y extension de la pierna y flexion del codo Bilateral deficit in leg flexion and extension and elbow flexion movements

    Directory of Open Access Journals (Sweden)

    Christianne Pereira Giesbrecht Chaves

    2004-12-01

    áxima (CM en la flexión y extensión de pierna e flexión del de codo aisladamente y entre la suma de esos dos resultados con aquel desarrollado simultaneamente por las dos piernas y los dos brazos, respectivamente. Sometemos a 60 indivíduos al ejercicio de flexión y extensión de pierna y a flexión de codo a un test de 1RM. Los resultados para los movimientos de flexión y extensión de pierna y flexión de codo izquierdos y derechos en la CM fueron de 31,6 (± 7,9, 32,0 (± 8,0, 20,2 (± 9,2, 20,2 (± 9,8, 29,3 (± 13,9 e 29,8 (± 14,1 kg respectivamente, y se mostraron similares (p > 0,05 y fuertemente asociados (r = 0,96, 0,96 e 0,98. Comparando la suma de los valores unilaterales con los de ejecución bilateral, la CM presentó una diferencia significativa para los movimientos de extensión de pierna (p = 0,04 y flexión de codo (p = 0,03, el mismo no fué observado en el movimiento de flexión de pierna (p = 0,75. Este resultado puede ser explicado por el menor incremento de carga - dos kilos y medio en este último movimiento en relación a los dos movimientos anteriores - cinco kilos. A pesar de la mayoría de los sujetos sean diestros, no hubo diferencias unilaterales en la CM a pesar de no todos estar entrenados. La suma de los resultados unilaterales fué mayor en 9,8% y 4,0% para los movimientos de extensión de la pierna y flexión del codo, respectivamente, de aquel obtenido bilateralmente, mostrando, probablemente una limitación central en la coordenación motora de un movimiento complejo hecho en máxima velocidad y con carga elevada. Por otro lado, en el movimiento de flexión de pierna, la suma de los resultados unilaterales fué inferior a la bilateral (-0,6%, presentando un posible aprendizage del movimiento y adaptación al entrenamiento con pesos a partir de las doce semanas.Endurance exercises (EE may be performed unilaterally and bilaterally. The objective was to compare the maximum load (ML in leg flexion and extension and elbow flexion alone

  13. Comparison of Static Force Sense of Knee Extension between Women with Patellofemoral Pain Syndrome and Healthy Women

    Directory of Open Access Journals (Sweden)

    Zahra Salah-Zadeh

    2008-01-01

    Full Text Available Objectives: Patellofemoaral pain syndrome (PFPS is a common musculoskeletal disorder. Proprioception is important factor in neuromuscular control. Others studies showed that, because of pain and abnormal stresses on soft tissue around joint and Proprioception may be change in these patients. The aim of this study was investigation of sense of quadriceps muscle force accuracy in patients with PFPS. Materials & Methods: In this cross-sectional and case –control study, thirty four young women with and without PFPS were participated. Biodex isokinetic dynamometer was used to measure isometric torque and sense of quadriceps static force. Force matching with ipsilateral limb was used by determining of reference force levels (20 and 60% of maximal voluntary isometric force (MVIF in 20 and 60 degree of knee flexion and attempting to perception and reproduction of target forces .Absolute error (AE, constant error (CE and variability error (VE were calculated for evaluation sense of force accuracy. Data were analyzed by independent T test and Logistics Regression. Results: There was statistically difference in force reproduction error in 60 degree and 60% MVIF between two groups (P<0.005. Sense of force errors were high in patient group. Conclusion: The results confirmed the past studies and showed that proprioception may be altered in PFPS patients because of changes proprioception afferents, specially for quadriceps muscle receptors.

  14. Leg lengthening - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100127.htm Leg lengthening - series—Indications To use the sharing features ... with lengthening procedures are the bones of the leg, the tibia and the femur. Surgical treatment may ...

  15. Arterial bypass leg - slideshow

    Science.gov (United States)

    ... medlineplus.gov/ency/presentations/100155.htm Arterial bypass leg - series—Normal anatomy To use the sharing features ... Overview The arteries which supply blood to the leg originate from the aorta and iliac vessels. Review ...

  16. Leg lengthening and shortening

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002965.htm Leg lengthening and shortening To use the sharing features on this page, please enable JavaScript. Leg lengthening and shortening are types of surgery to ...

  17. Comparison of a laboratory grade force platform with a Nintendo Wii balance board in measurement of postural control in single-legged stance balance tasks

    NARCIS (Netherlands)

    Huurnink, A.; Fransz, D.P.; Kingma, I.; van Dieen, J.H.

    2013-01-01

    Training and testing of balance have potential applications in sports and medicine. Laboratory grade force plates (FP) are considered the gold standard for the measurement of balance performance. Measurements in these systems are based on the parameterization of center of pressure (CoP)

  18. Foot, leg, and ankle swelling

    Science.gov (United States)

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Foot, leg, and ankle swelling is common when the person also: Is overweight Has a blood clot in the leg Is older Has ...

  19. Restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Ovallath S

    2012-10-01

    Full Text Available Sujith Ovallath, P DeepaJames Parkinson's Movement Disorder Research Centre, Kannur Medical College, Kerala, IndiaBackground: Restless legs syndrome (RLS is a common sleep-related disorder characterized by abnormal sensation and an urge to move the lower limbs. Symptoms occur at rest in the evening or at night, and they are alleviated by moving the affected extremity or by walking. Although the exact etiopathogenesis of RLS remains elusive, the rapid improvement of symptoms with dopaminergic agents suggests that dopaminergic system dysfunction may be a basic mechanism. Dopaminergic agents are the best-studied agents, and are considered first-line treatment of RLS.Objective: To review the diagnostic criteria, clinical features, etiopathogenesis, and the treatment options of RLS.Methods: The suggestions are based on evidence from studies published in peer-reviewed journals, or upon a comprehensive review of the medical literature.Results/conclusion: Extensive data are available for proving the link between the dopaminergic system and RLS. A possible genetic link also has been studied extensively. Dopamine agonists, especially pramipexole and ropinirole, are particularly useful in the treatment of RLS. Pharmacological treatment should however be limited to those patients who suffer from clinically relevant RLS with impaired sleep quality or quality of life.Keywords: dopamine, levodopa, pramipexole

  20. Pediatric restless legs syndrome diagnostic criteria: an update by the International Restless Legs Syndrome Study Group.

    Science.gov (United States)

    Picchietti, Daniel L; Bruni, Oliviero; de Weerd, Al; Durmer, Jeffrey S; Kotagal, Suresh; Owens, Judith A; Simakajornboon, Narong

    2013-12-01

    Specific diagnostic criteria for pediatric restless legs syndrome (RLS) were published in 2003 following a workshop at the National Institutes of Health. Due to substantial new research and revision of the adult RLS diagnostic criteria, a task force was chosen by the International Restless Legs Syndrome Study Group (IRLSSG) to consider updates to the pediatric diagnostic criteria. A committee of seven pediatric RLS experts developed a set of 15 consensus questions to review, conducted a comprehensive literature search, and extensively discussed potential revisions. The committee recommendations were approved by the IRLSSG executive committee and reviewed by the IRLSSG membership. The pediatric RLS diagnostic criteria were simplified and integrated with the newly revised adult RLS criteria. Specific recommendations were developed for pediatric application of the criteria, including consideration of typical words used by children to describe their symptoms. Pediatric aspects of differential diagnosis, comorbidity, and clinical significance were then defined. In addition, the research criteria for probable and possible pediatric RLS were updated and criteria for a related condition, periodic limb movement disorder (PLMD), were clarified. Revised diagnostic criteria for pediatric RLS have been developed, which are intended to improve clinical practice and promote further research. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Comparison of a laboratory grade force platform with a Nintendo Wii balance board in measurement of postural control in single-legged stance balance tasks

    OpenAIRE

    Huurnink, A.; Fransz, D.P.; Kingma, I.; van Dieen, J.H.

    2013-01-01

    Training and testing of balance have potential applications in sports and medicine. Laboratory grade force plates (FP) are considered the gold standard for the measurement of balance performance. Measurements in these systems are based on the parameterization of center of pressure (CoP) trajectories. Previous research validated the inexpensive, widely available and portable Nintendo Wii Balance Board (WBB). The novelty of the present study is that FP and WBB are compared on CoP data that was ...

  2. Venous leg ulcers.

    Science.gov (United States)

    Nelson, E Andrea; Adderley, Una

    2016-01-15

    Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0 in 1000 people have active leg ulcers. Prevalence increases with age to about 20 in 1000 people aged over 80 years. We conducted a systematic overview, aiming to answer the following clinical questions: What are the effects of treatments for venous leg ulcers? What are the effects of organisational interventions for venous leg ulcers? What are the effects of advice about self-help interventions in people receiving usual care for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2014 (Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview). At this update, searching of electronic databases retrieved 116 studies. After deduplication and removal of conference abstracts, 63 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 43 studies and the further review of 20 full publications. Of the 20 full articles evaluated, four systematic reviews were updated and four RCTs were added at this update. We performed a GRADE evaluation for 23 PICO combinations. In this systematic overview, we categorised the efficacy for 13 interventions based on information about the effectiveness and safety of advice to elevate leg, advice to keep leg active, compression stockings for prevention of recurrence, compression bandages and stockings to treat venous leg ulcers, laser treatment (low level), leg ulcer clinics, pentoxifylline, skin grafting, superficial vein surgery for prevention of recurrence, superficial vein surgery to treat venous leg ulcers, therapeutic ultrasound, and topical negative pressure.

  3. Muscle fatigue and exhaustion during dynamic leg exercise in normoxia and hypobaric hypoxia

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1996-01-01

    Using an exercise device that integrates maximal voluntary static contraction (MVC) of knee extensor muscles with dynamic knee extension, we compared progressive muscle fatigue, i.e., rate of decline in force-generating capacity, in normoxia (758 Torr) and hypobaric hypoxia (464 Torr). Eight...... healthy men performed exhaustive constant work rate knee extension (21 +/- 3 W, 79 +/- 2 and 87 +/- 2% of 1-leg knee extension O2 peak uptake for normoxia and hypobaria, respectively) from knee angles of 90-150 degrees at a rate of 1 Hz. MVC (90 degrees knee angle) was performed before dynamic exercise...... and during MVC force was 578 +/- 29 N in normoxia and 569 +/- 29 N in hypobaria before exercise and fell, at exhaustion, to similar levels (265 +/- 10 and 284 +/- 20 N for normoxia and hypobaria, respectively; P > 0.05) that were higher (P

  4. Effects of bodyweight-based exercise training on muscle functions of leg multi-joint movement in elderly individuals.

    Science.gov (United States)

    Yamauchi, Junichiro; Nakayama, Satoshi; Ishii, Naokata

    2009-09-01

    Because demands of functional exercise training with using own bodyweight for elderly individuals were increasing, the present study investigated the effects of bodyweight-based exercise training on muscle functions of leg multi-joint movements in elderly individuals. Twenty-seven untrained healthy elderly individuals (mean +/- standard deviation, 66.0 +/- 5.7 years) completed the training program for 10 months. The exercise program consisted mainly of exercises for large leg muscle groups without using external weight, performing 10-50 repetitions and 1-3 sets for each exercise. Before and after the training period, force-velocity relations of knee-hip extension movements were measured with a servo-controlled dynamometer and the maximum force (Fmax), velocity (Vmax) and power (Pmax) were determined. After the training, Fmax and Pmax increased and these increases represented 15% (P elderly individuals; however, the initial training status is important for progressive increases in muscle force.

  5. Transverse forces versus modified ashworth scale for upper limb flexion/extension in para-sagittal plane.

    Science.gov (United States)

    Seth, Nitin; Johnson, Denise; Abdullah, Hussein A

    2017-07-01

    Spasticity is a common impairment following an upper motor neuron lesion in conditions such as stroke and brain injury. A clinical issue is how to best quantify and measure spasticity. Recently, research has been performed to develop new methods of spasticity quantification using various systems. This paper follows up on previous work taking a closer look at the role of transversal forces obtained via rehabilitation robot for motions in the para-sagittal plane. Results from 45 healthy individuals and 40 individuals with acquired brain injury demonstrate that although the passive upper motions are vertical, horizontal forces into and away from the individual's body demonstrate a relationship with the Modified Ashworth Scale. This finding leads the way to new avenues of spasticity quantification and monitoring.

  6. Steerable Hopping Six-Legged Robot

    Science.gov (United States)

    Younse, Paulo; Aghazarian, Hrand

    2010-01-01

    The figure depicts selected aspects of a six-legged robot that moves by hopping and that can be steered in the sense that it can be launched into a hop in a controllable direction. This is a prototype of hopping robots being developed for use in scientific exploration of rough terrain on remote planets that have surface gravitation less than that of Earth. Hopping robots could also be used on Earth, albeit at diminished hopping distances associated with the greater Earth gravitation. The upper end of each leg is connected through two universal joints to an upper and a lower hexagonal frame, such that the tilt of the leg depends on the relative position of the two frames. Two non-back-driveable worm-gear motor drives are used to control the relative position of the two frames along two axes 120 apart, thereby controlling the common tilt of all six legs and thereby, further, controlling the direction of hopping. Each leg includes an upper and a lower aluminum frame segment with a joint between them. A fiberglass spring, connected via hinges to both segments, is used to store hopping energy prior to launch into a hop and to cushion the landing at the end of the hop. A cable for loading the spring is run into each leg through the center of the universal joints and then down along the center lines of the segments to the lower end of the leg. A central spool actuated by a motor with a harmonic drive and an electromagnetic clutch winds in all six cables to compress all six springs (thereby also flexing all six legs) simultaneously. To ensure that all the legs push off and land in the same direction, timing- belt pulley drives are attached to the leg segments, restricting the flexing and extension of all six legs to a common linear motion. In preparation for a hop, the spool can be driven to load the spring legs by an amount corresponding to a desired hop distance within range. The amount of compression can be computed from the reading of a shaft-angle encoder that

  7. Dynamically Stable Legged Locomotion.

    Science.gov (United States)

    1983-01-27

    balanced itself in 31) using a tabular ctontrol sclwnme. With only thUiee actuated degrees it used a shuffling gait to balance that reminds one of Charlie ... Chaplin . * The present study explores the control of a physical one-legged hopping machine. The objective of using a machine with only one leg was to

  8. Lyden-af-Leg

    DEFF Research Database (Denmark)

    Toft, Herdis

    Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform.......Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform....

  9. Secondary hyperparathyroidism: Uncommon cause of a leg ulcer

    NARCIS (Netherlands)

    van Rijssen, L. B.; Brenninkmeijer, E. E. A.; Nieveen van Dijkum, E. J. M.

    2012-01-01

    Most leg ulcers are vascular based. Only if vascular therapy fails other causes are considered. We report the case of a female with incapacitating leg ulcers caused by a rare condition which was only diagnosed after failing treatment. PRESENTATION OF CASE: The female had an extensive previous

  10. Effects of unilateral leg muscle fatigue on balance control in perturbed and unperturbed gait in healthy elderly.

    Science.gov (United States)

    Toebes, Marcel J P; Hoozemans, Marco J M; Dekker, Joost; van Dieën, Jaap H

    2014-01-01

    This study assessed effects of unilateral leg muscle fatigue (ULMF) on balance control in gait during the stance and swing phases of the fatigued leg in healthy elderly, to test the assumption that leg muscle strength limits balance control during the stance-phase. Ten subjects (aged 63.4, SD 5.5 years) walked on a treadmill in 4 conditions: unperturbed unfatigued, unperturbed fatigued, perturbed unfatigued, and perturbed fatigued. The perturbations were lateral trunk pulls just before contralateral heel contact. ULMF was evoked by unilateral squat exercise until task failure. Isometric knee extension strength was measured to verify the presence of muscle fatigue. Between-stride standard deviations and Lyapunov exponents of trunk kinematics were used as indicators of balance control. Required perturbation force and the deviation of trunk kinematics from unperturbed gait were used to assess perturbation responses. Knee extension strength decreased considerably (17.3% SD 8.6%) as a result ULMF. ULMF did not affect steady-state gait balance. Less force was required to perturb subjects when the fatigued leg was in the stance-phase compared to the swing-phase. Subjects showed a faster return to the unperturbed gait pattern in the fatigued than in the unfatigued condition, after perturbations in swing and stance of the fatigued leg. The results of this study are not in line with the hypothesized effects of leg muscle fatigue on balance in gait. The healthy elderly subjects were able to cope with substantial ULMF during steady-state gait and demonstrated faster balance recovery after laterally directed mechanical perturbations in the fatigued than in the unfatigued condition. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography.

    Science.gov (United States)

    Ali, Asraf; Sundaraj, Kenneth; Badlishah Ahmad, R; Ahamed, Nizam Uddin; Islam, Anamul; Sundaraj, Sebastian

    2015-06-27

    The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = -2.863), followed by the medial head (slope = -2.412) and the lateral head (slope = -1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

  12. Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography

    Directory of Open Access Journals (Sweden)

    Ali Md. Asraf

    2015-06-01

    Full Text Available The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = −2.863, followed by the medial head (slope = −2.412 and the lateral head (slope = −1.877 of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

  13. Epidemiology of extensive drug resistant Acinetobacter baumannii (XDRAB) at Security Forces Hospital (SFH) in Kingdom of Saudi Arabia (KSA).

    Science.gov (United States)

    Al-Obeid, Suleiman; Jabri, Lina; Al-Agamy, Mohammad; Al-Omari, Awad; Shibl, Atef

    2015-06-01

    Extensively drug-resistant Acinetobacter baumannii (XDRAB) became a worldwide nosocomial threat. The aim of this study was to assess the epidemiology and to evaluate the prevalence of carbapenem-resistant A. baumannii (CRAB). We also discuss therapeutic options for the management of their infections. Antibiotic susceptibility was determined in 506, 510 and 936 duplicate isolates of A. baumannii isolated in 2006, 2009 and 2012, respectively. In 2012, 12 unique XDRAB strains were isolated from patients with serious ventilator-associated pneumonia (VAP). Susceptibility tests were performed using the microdilution method according to Clinical and Laboratory Standards Institute (CLSI) recommendations. MICs were determined in triplicate by E-test according to the manufacturer's recommendations. Susceptible and multidrug-resistant A. baumannii (MDRAB) strains were detected using CHROMagar Acinetobacter medium. Carbapenem resistant A. baumannii was investigated for carbapenemase production by the modified Hodge test (MHT) and by multiplex PCR. A Synergy test was performed using the E-test method. Considering years 2006, 2009 and 2012, the susceptibilities to meropenem and imipenem were 64-81.2%, 34.5-45.3%, and 8.3-11%, respectively. Concerning the 12 XDRAB strains, all isolates were susceptible to colistin and resistant to meropenem and imipenem. Culture on CHROMagar Acinetobacter confirmed that all are MDRAB. The gene profiles detected in PCR assays showed that all the strains possess OXA-51.Out of the 12 isolates, 11 possess the oxa-23 gene and one harbours the gene 24/40. A good synergistic effect was detected between colistin and tigecycline. In this study, A. baumannii susceptibility to carbapenems showed a drastic reduction and represents a major epidemiological concern. The main carbapenem resistance mechanism is mediated by class D-OXA-type enzymes (oxa-23 and oxa-24/40) with Carbapenemase activity. Therapeutic options are exceedingly limited, relying on polymyxin

  14. RESTLESS LEGS SYNDROME

    Directory of Open Access Journals (Sweden)

    Dmitriy Valer'evich Artem'ev

    2009-01-01

    Full Text Available The paper describes the epidemiology, etiology, pathogenesis, clinical picture, diagnosis, differential diagnosis, and treatment of restless legs syndrome. Recommendations are given how to choose therapeutic modalities and drugs in relation to different factors.

  15. Restless legs syndrome.

    Science.gov (United States)

    Venkateshiah, Saiprakash B; Ioachimescu, Octavian C

    2015-07-01

    Restless legs syndrome is a common sensorimotor disorder characterized by an urge to move, and associated with uncomfortable sensations in the legs (limbs). Restless legs syndrome can lead to sleep-onset or sleep-maintenance insomnia, and occasionally excessive daytime sleepiness, all leading to significant morbidity. Brain iron deficiency and dopaminergic neurotransmission abnormalities play a central role in the pathogenesis of this disorder, along with other nondopaminergic systems, although the exact mechanisms are still. Intensive care unit patients are especially vulnerable to have unmasking or exacerbation of restless legs syndrome because of sleep deprivation, circadian rhythm disturbance, immobilization, iron deficiency, and use of multiple medications that can antagonize dopamine. Published by Elsevier Inc.

  16. Joint variable stiffness of musculoskeletal leg mechanism for quadruped robot

    OpenAIRE

    Lei, J; Zhu, J; Xie, P; Tokhi, MO

    2017-01-01

    © The Author(s) 2017. When the quadruped robot is in locomotion such as jumping and running with higher speed, there is non-continuous contact force between the foot and the environment inevitably. In order to achieve the flexible force interaction of the bionic legs with the environment, it is necessary to analyze the joint angular stiffness of the bionic leg. In this article, based on the designing principles of the bionics, light-weighted, and flexible, a kind of musculoskeletal bionic leg...

  17. Venous leg ulcers.

    Science.gov (United States)

    Nelson, E Andrea

    2011-12-21

    Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0/1000 people have active leg ulcers. Prevalence increases with age to about 20/1000 in people aged over 80 years. We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of standard treatments, adjuvant treatments, and organisational interventions for venous leg ulcers? What are the effects of advice about self-help interventions in people receiving usual care for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 101 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: compression bandages and stockings, cultured allogenic (single or bilayer) skin replacement, debriding agents, dressings (cellulose, collagen, film, foam, hyaluronic acid-derived, semi-occlusive alginate), hydrocolloid (occlusive) dressings in the presence of compression, intermittent pneumatic compression, intravenous prostaglandin E1, larval therapy, laser treatment (low-level), leg ulcer clinics, multilayer elastic system, multilayer elastomeric (or non-elastomeric) high-compression regimens or bandages, oral treatments (aspirin, flavonoids, pentoxifylline, rutosides, stanozolol, sulodexide

  18. Proprioceptive Actuation Design for Dynamic Legged locomotion

    Science.gov (United States)

    Kim, Sangbae; Wensing, Patrick; Biomimetic Robotics Lab Team

    Designing an actuator system for highly-dynamic legged locomotion exhibited by animals has been one of the grand challenges in robotics research. Conventional actuators designed for manufacturing applications have difficulty satisfying challenging requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. It is critical to introduce a new actuator design paradigm and provide guidelines for its incorporation in future mobile robots for research and industry. To this end, we suggest a paradigm called proprioceptive actuation, which enables highly- dynamic operation in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. Results show that the proposed design provides an impact mitigation factor that is comparable to other quadruped designs with series springs to handle impact. The paradigm is shown to enable the MIT Cheetah to manage the application of contact forces during dynamic bounding, with results given down to contact times of 85ms and peak forces over 450N. As a result, the MIT Cheetah achieves high-speed 3D running up to 13mph and jumping over an 18-inch high obstacle. The project is sponsored by DARPA M3 program.

  19. Three-dimensional topographies of water surface dimples formed by superhydrophobic water strider legs

    Science.gov (United States)

    Yin, W.; Zheng, Y. L.; Lu, H. Y.; Zhang, X. J.; Tian, Y.

    2016-10-01

    A water strider has a remarkable capability to stand and walk freely on water. Supporting forces of a water strider and a bionic robot have been calculated from the side view of pressed depth of legs to reconstruct the water surface dimples. However, in situ measurements of the multiple leg forces and significantly small leg/water contact dimples have not been realized yet. In this study, a shadow method was proposed to reconstruct the in situ three-dimensional topographies of leg/water contact dimples and their corresponding supporting forces. Results indicated that the supporting forces were affected by the depth, width, and length of the dimple, and that the maximum dimple depth was not proportional to the supporting forces. The shadow method also has advantages in disclosing tiny supporting force of legs in their subtle actions. These results are helpful for understanding the locomotion principles of water-walking insects and the design of biomimetic aquatic devices.

  20. Differences in take-off leg kinetics between horizontal and vertical single-leg rebound jumps.

    Science.gov (United States)

    Kariyama, Yasushi; Hobara, Hiroaki; Zushi, Koji

    2017-06-01

    This study aimed to clarify the differences between the horizontal single-leg rebound jump (HJ) and vertical single-leg rebound jump (VJ) in terms of three-dimensional joint kinetics for the take-off leg, while focusing on frontal and transverse plane movements. Eleven male track and field athletes performed HJ and VJ. Kinematic and kinetic data were calculated using data recorded with a motion capture system and force platforms. The hip abduction torque, trunk lateral flexion torque (flexion for the swing-leg side), hip external and internal torque, trunk rotational torque, and the powers associated with these torques were larger when performing HJ because of resistance to the impact ground reaction force and because of pelvic and posture control. Pelvic rotation was noted in HJ, and this was controlled not only by the hip and trunk joint torque from the transverse plane but also by the hip abduction torque. Therefore, hip and trunk joint kinetics in the frontal and transverse plane play an important role in a single-leg jump, regardless of the jumping direction, and may also play a more important role in HJ than in VJ.

  1. Does weightlifting increase residual force enhancement?

    Science.gov (United States)

    Siebert, Tobias; Kurch, David; Blickhan, Reinhard; Stutzig, Norman

    2016-07-05

    The force maintained following stretching of an active muscle exceeds the isometric force at the same muscle length. This residual force enhancement (RFE) is different for various muscles. It is currently unknown whether training induces changes in RFE. Weightlifters perform a large number of eccentric contractions during training, and RFE might be functionally relevant. The aim of this study was to examine whether there is increased RFE in weightlifters versus a reference group. Therefore, we measured external reaction forces during a multi-joint leg extension in weightlifters (n=10) and a reference group (n=11) using a motor driven leg press dynamometer (ISOMED 2000). Steady state isometric forces after stretching were compared to the corresponding forces obtained during isometric reference contractions. Statistical analyses yielded a significant RFE for both groups (pweightlifting group versus the reference group. We conclude that long-term weightlifting has only a minor influence on RFE. We speculate that the specific training including a combination of eccentric and concentric exercises induced almost no changes in titin-isoform expression which may be responsible for generation of RFE after active muscle stretching. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. ORTHOPEDIC LEG BRACE

    Science.gov (United States)

    Myers, William Neil (Inventor)

    2005-01-01

    Knee braces generally have been rigid in both the knee bending direction and in the knee straightening direction unless a manually operated release is incorporated in them to allow the knee to bend. Desirably a braced knee joint should effectively duplicate the compound, complex, actions of a normal knee. The key to knee braces is the knee joint housing. The housing herein carries a number of cam action pawls. with teeth adapted to engage the internal teeth of a ratchet ring mounted in the housing. Cam action return springs and the shape of the cam action pawl teeth allow rotation of the ratchet ring in a leg straightening direction while still supporting a load. The leg can then be extended during walking while at the same time being prevented by the cam action pawls from buckling in the knee bending direction.

  3. Hind wings in Basal birds and the evolution of leg feathers.

    Science.gov (United States)

    Zheng, Xiaoting; Zhou, Zhonghe; Wang, Xiaoli; Zhang, Fucheng; Zhang, Xiaomei; Wang, Yan; Wei, Guangjin; Wang, Shuo; Xu, Xing

    2013-03-15

    Recent discoveries of large leg feathers in some theropods have implications for our understanding of the evolution of integumentary features on the avialan leg, and particularly of their relevance for the origin of avialan flight. Here we report 11 basal avialan specimens that will greatly improve our knowledge of leg integumentary features among early birds. In particular, they provide solid evidence for the existence of enlarged leg feathers on a variety of basal birds, suggest that extensively scaled feet might have appeared secondarily at an early stage in ornithuromorph evolution, and demonstrate a distal-to-proximal reduction pattern for leg feathers in avialan evolution.

  4. Legāti

    OpenAIRE

    Segliņa, Aiga

    2010-01-01

    Autore teorētiski analizē legāta jēdzienu testamentārās mantošanas ietvaros un atspoguļo praktiska pētījuma rezultātus. Teorētiskā daļa apskata legāta nodibināšanas formu un spēkā esamību, tā iegūšanu un atraidīšanu, izpildi un zaudēšanu, novēlējuma robežas un aprobežojumus. Pētījums veikts aptaujas veidā ar mērķi noskaidrot, cik liela Latvijas iedzīvotāju daļa apzinās legāta nodrošinātās priekšrocības testamentārajā mantošanā. Apskatīts notāra neitralitātes jautājums attiecībā pret mantošana...

  5. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

    2011-01-01

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  6. 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.

  7. Reconstruction of human swing leg motion with passive biarticular muscle models.

    Science.gov (United States)

    Ahmad Sharbafi, Maziar; Mohammadi Nejad Rashty, Aida; Rode, Christian; Seyfarth, Andre

    2017-04-01

    Template models, which are utilized to demonstrate general aspects in human locomotion, mostly investigate stance leg operation. The goal of this paper is presenting a new conceptual walking model benefiting from swing leg dynamics. Considering a double pendulum equipped with combinations of biarticular springs for the swing leg beside spring-mass (SLIP) model for the stance leg, a novel SLIP-based model, is proposed to explain human-like leg behavior in walking. The action of biarticular muscles in swing leg motion helps represent human walking features, like leg retraction, ground reaction force and generating symmetric walking patterns, in simulations. In order to stabilize the motion by the proposed passive structure, swing leg biarticular muscle parameters such as lever arm ratios, stiffnesses and rest lengths need to be properly adjusted. Comparison of simulation results with human experiments shows the ability of the proposed model in replicating kinematic and kinetic behavior of both stance and swing legs as well as biarticular thigh muscle force of the swing leg. This substantiates the important functional role of biarticular muscles in leg swing. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Comparison between Unilateral and Bilateral Plyometric Training on Single and Double Leg Jumping Performance and Strength.

    Science.gov (United States)

    Bogdanis, Gregory C; Tsoukos, Athanasios; Kaloheri, Olga; Terzis, Gerasimos; Veligekas, Panagiotis; Brown, Lee E

    2017-04-18

    This study compared the effects of unilateral and bilateral plyometric training on single and double-leg jumping performance, maximal strength and rate of force development (RFD). Fifteen moderately trained subjects were randomly assigned to either a unilateral (U, n=7) or bilateral group (B, n=8). Both groups performed maximal effort plyometric leg exercises two times per week for 6 weeks. The B group performed all exercises with both legs, while the U group performed half the repetitions with each leg, so that total exercise volume was the same. Jumping performance was assessed by countermovement jumps (CMJ) and drop jumps (DJ), while maximal isometric leg press strength and RFD were measured before and after training for each leg separately and both legs together. CMJ improvement with both legs was not significantly different between U (12.1±7.2%) and B (11.0±5.5%) groups. However, the sum of right and left leg CMJ only improved in the U group (19.0±7.1%, pplyometric training was more effective at increasing both single and double-leg jumping performance, isometric leg press maximal force and RFD when compared to bilateral training.

  9. How does postural stability following a single leg drop jump landing task relate to postural stability during a single leg stance balance task?

    NARCIS (Netherlands)

    Fransz, Duncan P.; Huurnink, Arnold; Kingma, Idsart; van Dieën, Jaap H.

    2014-01-01

    We aimed to verify whether the static phase after a single leg drop jump (DJ) landing on a force plate may serve as a proxy for a single leg stance (SLS) balance task, as this would increase the application possibilities of landing tasks in the evaluation of sensorimotor function in relation to

  10. Leg cramps and restless legs syndrome during pregnancy.

    Science.gov (United States)

    Hensley, Jennifer G

    2009-01-01

    Sleep disturbance during pregnancy can result in excessive daytime sleepiness, diminished daytime performance, inability to concentrate, irritability, and the potential for an increased length of labor and increased risk of operative birth. Sleep disturbance may be the result of a sleep disorder, such as leg cramps, a common yet benign disorder, or restless legs syndrome, a sensorimotor disorder. Both disrupt sleep, are distressing to the pregnant woman, and mimic one another and other serious disorders. During pregnancy, up to 30% of women can be affected by leg cramps, and up to 26% can be affected by restless legs syndrome.

  11. [Swollen leg with blisters].

    Science.gov (United States)

    Rafeiner, Ph; Templeton, A J; Vonesch, H J

    2005-10-05

    We report the case of a 84-year-old woman suffering from strong pain in her right leg initially resembling thrombosis of deep veins. Eight hours after admission a superficial blister developed at the calf with following hemorrhagic aspect and spontanous eruption of clear yellowish fluid. Later on a new blister appeared at the thigh. The patient died 33 hours after admission of streptococcal toxic shock syndrome. The latter was based on a necrotizing fasciitis. Streptoccus pyogenes (group A) could be cultivated from the blood and fluid of the blister. We discuss the clinical presentation of necrotizing fasciitis with "pain out of proportion" as characteristic complaint and the appropriate management.

  12. Textiloma in the leg

    Directory of Open Access Journals (Sweden)

    Patel Amol

    2007-01-01

    Full Text Available Textiloma is defined as a tumor formed due to retained gauze. It is rarely reported in the musculoskeletal system. We are presenting a case with a soft tissue swelling over the lateral aspect of the lower third of the leg, come for implant removal of the distal tibia and fibular fracture. We removed the soft tissue mass enbloc thinking it to be a benign tumor. On cutting the mass on the operation table, a gauze piece encased by fibrous tissue was found. Textiloma can present as tumoral forms and can mimic as a pseudo-tumor.

  13. Myonecrosis in the leg caused by Salmonella enteritidis

    DEFF Research Database (Denmark)

    Jørring, S; Kolmos, H J; Klareskov, B

    1994-01-01

    Five weeks after an episode of gastroenteritis, a 65-year-old diabetic male developed an extensive myonecrosis, with gas production in the left leg caused by Salmonella enteritidis. The patient was treated with surgical revision and antibiotics. To our knowledge, this is the first case of myonecr......Five weeks after an episode of gastroenteritis, a 65-year-old diabetic male developed an extensive myonecrosis, with gas production in the left leg caused by Salmonella enteritidis. The patient was treated with surgical revision and antibiotics. To our knowledge, this is the first case...

  14. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    OpenAIRE

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, ...

  15. The effect of spinal manipulation on imbalances in leg strength.

    Science.gov (United States)

    Chilibeck, Philip D; Cornish, Stephen M; Schulte, Al; Jantz, Nathan; Magnus, Charlene R A; Schwanbeck, Shane; Juurlink, Bernhard H J

    2011-09-01

    We hypothesized that spinal manipulation (SM) would reduce strength imbalances between legs. Using an un-blinded randomized design, 28 males and 21 females (54 ± 19y) with at least a 15% difference in isometric strength between legs for hip flexion, extension, abduction, or knee flexion were randomized to treatment or placebo (mock spinal manipulation). Strength of the stronger and weaker legs for hip flexion, extension, abduction, and/or knee flexion was assessed before and after the intervention. SM reduced the relative strength difference between legs for knee flexion (mean ± SD 57 ± 53 to 5 ± 14%) and hip flexion (24 ± 12 to 11 ± 15%) compared to placebo (34 ± 29 to 24 ± 36%, and 20 ± 18 to 22 ± 26%, respectively) (p = 0.05). SM also improved strength in the weak leg for hip abduction (104 ± 43 to 116 ± 43 Nm) compared to placebo (84 ± 24 to 85 ± 31 Nm) (p = 0.03). This study suggests that spinal manipulation may reduce imbalances in strength between legs for knee and hip flexion.

  16. Effects of Heavy-Resistance Strength and Balance Training on Unilateral and Bilateral Leg Strength Performance in Old Adults

    Science.gov (United States)

    Beurskens, Rainer; Gollhofer, Albert; Muehlbauer, Thomas; Cardinale, Marco; Granacher, Urs

    2015-01-01

    The term “bilateral deficit” (BLD) has been used to describe a reduction in performance during bilateral contractions when compared to the sum of identical unilateral contractions. In old age, maximal isometric force production (MIF) decreases and BLD increases indicating the need for training interventions to mitigate this impact in seniors. In a cross-sectional approach, we examined age-related differences in MIF and BLD in young (age: 20–30 years) and old adults (age: >65 years). In addition, a randomized-controlled trial was conducted to investigate training-specific effects of resistance vs. balance training on MIF and BLD of the leg extensors in old adults. Subjects were randomly assigned to resistance training (n = 19), balance training (n = 14), or a control group (n = 20). Bilateral heavy-resistance training for the lower extremities was performed for 13 weeks (3 × / week) at 80% of the one repetition maximum. Balance training was conducted using predominately unilateral exercises on wobble boards, soft mats, and uneven surfaces for the same duration. Pre- and post-tests included uni- and bilateral measurements of maximal isometric leg extension force. At baseline, young subjects outperformed older adults in uni- and bilateral MIF (all p training (all p training (all p training (p training regimens resulted in increased MIF and decreased BLD of the leg extensors (HRT-group more than BAL-group), almost reaching the levels of young adults. PMID:25695770

  17. Modeling posture-dependent leg actuation in sagittal plane locomotion

    International Nuclear Information System (INIS)

    Schmitt, J; Clark, J

    2009-01-01

    The spring loaded inverted pendulum template has been shown to accurately model the steady locomotion dynamics of a variety of running animals, and has served as the inspiration for an entire class of dynamic running robots. While the template models the leg dynamics by an energy-conserving spring, insects and animals have structures that dissipate, store and produce energy during a stance phase. Recent investigations into the spring-like properties of limbs, as well as animal response to drop-step perturbations, suggest that animals use their legs to manage energy storage and dissipation, and that this management is important for gait stability. In this paper, we extend our previous analysis of control of the spring loaded inverted pendulum template via changes in the leg touch-down angle to include energy variations during the stance phase. Energy variations are incorporated through leg actuation that varies the force-free leg length during the stance phase, yet maintains qualitatively correct force and velocity profiles. In contrast to the partially asymptotically stable gaits identified in previous analyses, incorporating energy and leg angle variations in this manner produces complete asymptotic stability. Drop-step perturbation simulations reveal that the control strategy is rather robust, with gaits recovering from drops of up to 30% of the nominal hip height.

  18. Modeling posture-dependent leg actuation in sagittal plane locomotion

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, J [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331 (United States); Clark, J, E-mail: schmitjo@engr.orst.ed [Department of Mechanical Engineering, Florida State University, Tallahassee, FL 32310 (United States)

    2009-12-15

    The spring loaded inverted pendulum template has been shown to accurately model the steady locomotion dynamics of a variety of running animals, and has served as the inspiration for an entire class of dynamic running robots. While the template models the leg dynamics by an energy-conserving spring, insects and animals have structures that dissipate, store and produce energy during a stance phase. Recent investigations into the spring-like properties of limbs, as well as animal response to drop-step perturbations, suggest that animals use their legs to manage energy storage and dissipation, and that this management is important for gait stability. In this paper, we extend our previous analysis of control of the spring loaded inverted pendulum template via changes in the leg touch-down angle to include energy variations during the stance phase. Energy variations are incorporated through leg actuation that varies the force-free leg length during the stance phase, yet maintains qualitatively correct force and velocity profiles. In contrast to the partially asymptotically stable gaits identified in previous analyses, incorporating energy and leg angle variations in this manner produces complete asymptotic stability. Drop-step perturbation simulations reveal that the control strategy is rather robust, with gaits recovering from drops of up to 30% of the nominal hip height.

  19. 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

  20. Emphysematous Pyelonephritis Presenting as Necrotizing Fasciitis of the Leg

    Directory of Open Access Journals (Sweden)

    Yu-Xiong Ye

    2009-03-01

    Full Text Available We report a 50-year-old man with poorly controlled diabetes mellitus who presented with a painful, swollen right leg. He had also experienced right flank pain for 1 week prior to admission. Physical examination was notable for tenderness over the right flank. The right leg was diffusely swollen and exquisitely tender to touch, with palpable crepitance. Laboratory tests revealed leukocytosis and pyuria. Computed tomography showed a right ureteral stone with hydronephrosis and characteristic findings of emphysematous pyelonephritis. Furthermore, a right perirenal gas-forming abscess with extension to the right leg was noted. The patient was successfully treated with antibiotic therapy, aggressive control of blood sugar, percutaneous drainage of the hydronephrosis and perirenal abscess, and aggressive debridement of the leg.

  1. Dynamic Leg Exercise Improves Tolerance to Lower Body Negative Pressure

    Science.gov (United States)

    Watenpaugh, D. E.; Ballard, R. E.; Stout, M. S.; Murthy, G.; Whalen, R. T.; Hargens, A. R.

    1994-01-01

    These results clearly demonstrate that dynamic leg exercise against the footward force produced by LBNP substantially improves tolerance to LBNP, and that even cyclic ankle flexion without load bearing also increases tolerance. This exercise-induced increase of tolerance was actually an underestimate, because subjects who completed the tolerance test while exercising could have continued for longer periods. Exercise probably increases LBNP tolerance by multiple mechanisms. Tolerance was increased in part by skeletal muscle pumping venous blood from the legs. Rosenhamer and Linnarsson and Rosenhamer also deduced this for subjects cycling during centrifugation, although no measurements of leg volume were made in those studies: they found that male subjects cycling at 98 W could endure 3 Gz centrifugation longer than when they remained relaxed during centrifugation. Skeletal muscle pumping helps maintain cardiac filling pressure by opposing gravity-, centrifugation-, or LBNP-induced accumulation of blood and extravascular fluid in the legs.

  2. Immobilization tests and periodic leg movements in sleep for the diagnosis of restless leg syndrome.

    Science.gov (United States)

    Montplaisir, J; Boucher, S; Nicolas, A; Lesperance, P; Gosselin, A; Rompré, P; Lavigne, G

    1998-03-01

    Patients with restless leg syndrome (RLS) complain of motor restlessness, usually occurring while they rest in the evening. Two immobilization tests have been described to assess leg restlessness in these patients. In the first test, the patient sits in bed with his or her legs outstretched while electromyograms are recorded from right and left anterior tibialis muscles for an hour (Suggested Immobilization Test [SIT]); in the second test, the legs are immobilized in a stretcher (Forced Immobilization Test [FIT]). In the current study, the SIT and the FIT were compared in patients with RLS and normal control subjects matched for age and sex. More leg movements were seen in patients than in controls during immobilization tests, especially the SIT. These movements were periodic, occurring at a frequency of approximately one every 12 seconds. The SIT (index > 40) was found to discriminate between RLS and control subjects better than the FIT (index > 25). Patients were also recorded during two consecutive nights to measure periodic leg movements in sleep (PLMS). A SIT index greater than 40 and a PLMS index greater than 11 (highest PLMS index of 2 consecutive nights) were found to discriminate patients with RLS from control subjects with similar power. With each of these two measures, the clinical diagnosis was correctly predicted in 81% of patients and 81% of the control subjects. The SIT has several advantages over the measure of the PLMS index; it does not require an all-night polygraphic recording and can be administered several times a day to measure circadian fluctuation of motor restlessness.

  3. Propulsive force calculations in swimming frogs. I. A momentum-impulse approach.

    Science.gov (United States)

    Nauwelaerts, Sandra; Stamhuis, Eize J; Aerts, Peter

    2005-04-01

    Frogs are animals that are capable of locomotion in two physically different media, aquatic and terrestrial. A comparison of the kinematics of swimming frogs in a previous study revealed a difference in propulsive impulse between jumping and swimming. To explore this difference further, we determined the instantaneous forces during propulsion in swimming using an impulse-momentum approach based on DPIV flow data. The force profile obtained was compared with force profiles obtained from drag-thrust equilibrium of the centre of mass and with the force profiles generated during jumping. The new approach to quantifying the instantaneous forces during swimming was tested and proved to be a valid method for determining the external forces on the feet of swimming frogs. On the kinematic profiles of swimming, leg extension precedes propulsion. This means that it is not only the acceleration of water backwards that provides thrust, but also that the deceleration of water flowing towards the frog as a result of recovery accelerates the centre of mass prior to leg extension. The force profile obtained from the impulse-momentum approach exposed an overestimation of drag by 30% in the drag-thrust calculations. This means that the difference in impulse between jumping and swimming in frogs is even larger than previously stated. The difference between the force profiles, apart from a slightly higher peak force during jumping, lies mainly in a difference in shape. During swimming, maximal force is reached early in the extension phase, 20% into it, while during jumping, peak force is attained at 80% of the extension phase. This difference is caused by a difference in inter-limb coordination.

  4. Differentiating nocturnal leg cramps and restless legs syndrome.

    Science.gov (United States)

    Rana, Abdul Qayyum; Khan, Fatima; Mosabbir, Abdullah; Ondo, William

    2014-07-01

    Leg pain and discomfort are common complaints in any primary physician's clinic. Two common causes of pain or discomfort in legs are nocturnal leg cramps (NLC) and restless leg syndrome (RLS). NLC present as painful and sudden contractions mostly in part of the calf. Diagnosis of NLC is mainly clinical and sometimes involves investigations to rule out other mimics. RLS is a condition characterized by the discomfort or urge to move the lower limbs, which occurs at rest or in the evening/night. The similarity of RLS and leg cramps poses the issue of errors in diagnosing and differentiating the two. In this paper we review the pathopysiology of each entity and their diagnosis as well as treatment. The two conditions are then compared to appreciate the differences and similarities. Finally, suggestions are recommended for complete assessment.

  5. Military boot attenuates axial loading to the lower leg.

    Science.gov (United States)

    Yoganandan, Narayan; Schlick, Michael; Arun, Mike W J; Pintar, Frank A

    2014-01-01

    Biomechanical tests to understand injury mechanisms and derive injury tolerance information using Post-Mortem Human Subjects (PMHS) have not used foot protection and they have primarily focused on civilian environments such as automotive and athletic- and sports-related events. As military personnel use boots, tests with the boot are required to understand their effect on attenuating lower leg loads. The purpose of this study was therefore, to determine the modulation of human lower leg kinematics with boot compressions and share of the force absorbed by the boot from underbody blast loading. Axial impacts were delivered to the Hybrid III dummy lower leg in the neutral position. The dummy leg was instrumented with its internal upper and lower tibia load cells, and in addition, a knee load cell was attached to the proximal end. Tests were conducted at 4.4 to 8.9 m/s, with and without boots, and repeat tests were done. Morphologies of the force-time responses were similar at the three load cell locations and for all input combinations and booted and unbooted conditions. However, booted tests resulted in considerably lower maximum forces (approximately two-third reduction) than unbooted tests. These results clearly show that boots can absorb a considerable share of the impact energy and decrease impact loads transmitted to the lower leg under vertical loading, thus necessitating the generation of tolerance data using PMHS for this environment.

  6. On voluntary rhythmic leg movement behaviour and control during pedalling.

    Science.gov (United States)

    Hansen, E A

    2015-06-01

    The overall purpose of the present dissertation was to contribute to the understanding of voluntary human rhythmic leg movement behaviour and control. This was achieved by applying pedalling as a movement model and exposing healthy and recreationally active individuals as well as trained cyclists to for example cardiopulmonary and mechanical loading, fatiguing exercise, and heavy strength training. As a part of the background, the effect of pedalling frequency on diverse relevant biomechanical, physiological, and psychophysiological variables as well as on performance was initially explored. Freely chosen pedalling frequency is considerably higher than the energetically optimal pedalling frequency. This has been shown by others and was confirmed in the present work. As a result, pedal force is relatively low while rates of VO2 and energy turnover are relatively high during freely chosen pedalling as compared to a condition where a lower and more efficient pedalling frequency is imposed. The freely chosen pedalling frequency was in the present work, and by others, found to most likely be less advantageous than the lower energetically optimal pedalling frequency with respect to performance during intensive cycling following prolonged submaximal cycling. This stimulates the motivation to understand the behaviour and control of the freely chosen pedalling frequency during cycling. Freely chosen pedalling frequency was in the present work shown to be highly individual. In addition, the pedalling frequency was shown to be steady in a longitudinal perspective across 12 weeks. Further, it was shown to be unaffected by both fatiguing hip extension exercise and hip flexion exercise as well as by increased loading on the cardiopulmonary system at constant mechanical loading, and vice versa. Based on this, the freely chosen pedalling frequency is considered to be characterised as a highly individual, steady, and robust innate voluntary motor rhythm under primary influence of

  7. Klinefelter Syndrome With Leg Ulcers

    Directory of Open Access Journals (Sweden)

    Narendra G

    1999-01-01

    Full Text Available Leg ulcers are frequently caused by venous insufficiency, arterial insufficiency, neuropathy, or a combination of these factors. Klinefelter syndrome in association with chronic leg ulcers have been reported earlier. We report a case of Klinefelter syndrome with non- healing ulcer. The diagnosis of the Klinefelter syndrome was confirmed by karyotyping.

  8. Unilateral Eccentric Contraction of the Plantarflexors Leads to Bilateral Alterations in Leg Dexterity.

    Science.gov (United States)

    Nagamori, Akira; Valero-Cuevas, Francisco J; Finley, James M

    2016-01-01

    Eccentric contractions can affect musculotendon mechanical properties and disrupt muscle proprioception, but their behavioral consequences are poorly understood. We tested whether repeated eccentric contractions of plantarflexor muscles of one leg affected the dexterity of either leg. Twenty healthy male subjects (27.3 ± 4.0 yrs) compressed a compliant and slender spring prone to buckling with each isolated leg. The maximal instability they could control (i.e., the maximal average sustained compression force, or lower extremity dexterity force, LED force ) quantified the dexterity of each leg. We found that eccentric contractions did not affect LED force , but reduced force variability (LED SD ). Surprisingly, LED force increased in the non-exposed, contralateral leg. These effects were specific to exposure to eccentric contractions because an effort-matched exposure to walking did not affect leg dexterity. In the exposed leg, eccentric contractions (i) reduced voluntary error corrections during spring compressions (i.e., reduced 0.5-4 Hz power of LED force ); (ii) did not change spinal excitability (i.e., unaffected H-reflexes); and (iii) changed the structure of the neural drive to the α-motoneuron pool (i.e., reduced EMG power within the 4-8 Hz physiological tremor band). These results suggest that repeated eccentric contractions alter the feedback control for dexterity in the exposed leg by reducing muscle spindle sensitivity. Moreover, the unexpected improvement in LED force in the non-exposed contralateral leg was likely a consequence of crossed-effects on its spinal and supraspinal feedback control. We discuss the implications of these bilateral effects of unilateral eccentric contractions, their effect on spinal and supraspinal control of dynamic foot-ground interactions, and their potential to facilitate rehabilitation from musculoskeletal and neuromotor impairments.

  9. Spring-like leg behaviour, musculoskeletal mechanics and control in maximum and submaximum height human hopping

    NARCIS (Netherlands)

    Bobbert, M.F.

    2011-01-01

    The purpose of this study was to understand how humans regulate their 'leg stiffness' in hopping, and to determine whether this regulation is intended to minimize energy expenditure. 'Leg stiffness' is the slope of the relationship between ground reaction force and displacement of the centre of mass

  10. Biomechanical analysis of the single-leg decline squat

    NARCIS (Netherlands)

    Zwerver, J.; Bredeweg, S. W.; Hof, A. L.

    Background: The single-leg squat on a 25 decline board has been described as a clinical assessment tool and as a rehabilitation exercise for patients with patellar tendinopathy. Several assumptions have been made about its working mechanism on patellar load and patellofemoral forces, but these are

  11. Contralateral leg deficits in kinetic and kinematic variables during running in Australian rules football players with previous hamstring injuries.

    Science.gov (United States)

    Brughelli, Matt; Cronin, John; Mendiguchia, Jurdan; Kinsella, Dave; Nosaka, Ken

    2010-09-01

    Contralateral leg deficits between lower limbs during athletic movements are thought to increase the risk of injury and compromise performance. The purpose of this study was to quantify the magnitude of leg deficits during running in noninjured and previously injured Australian Rules football (ARF) players. The players included a group of noninjured ARF players (n = 11) and a group of previously injured ARF players (n = 11; hamstring injuries only). The players in the injured group (IG) had at least 1 acute hamstring injury in the previous 2 years. The legs of the noninjured players (NIG) were classified as right and left, whereas the legs of the injured players were classified as injured or noninjured. The players ran on a nonmotorized force treadmill at approximately 80% of their maximum velocity (Vmax). For the NIG, there were no significant differences between right and left legs for any of the variables. For the IG, the only variable that was significantly (p force (175 +/- 30 vs. 326 +/- 44 N). Furthermore, horizontal force was significantly greater in the noninjured leg (IG) in comparison with either legs in the NIG (19.2% and 20.5%) and significantly less in the injured leg (IG) in comparison with either legs of the NIG (31.5% and 32.7%). In the present study, athletes with previous hamstring injuries had contralateral leg deficits in horizontal but not vertical force during running at submaximal velocities.

  12. Restless legs syndrome: literature review

    Directory of Open Access Journals (Sweden)

    Emmanouil Symvoulakis

    Full Text Available Restless legs syndrome is a distressing condition, with negative effects on sleep and daytime activities that affect personal, family and occupational life. The overall impact of restless legs syndrome on quality of life is comparable to that of chronic and frustrating conditions such as depression and diabetes. Misdiagnosis and inappropriate treatment may increase patients' suffering in terms of uncertainty, overuse or misuse of care services and lack of trust. Presenting a synthesis of the main topics in the literature on restless legs syndrome facilitates for a better understanding and its management in primary care settings.

  13. Measurement of body fat using leg to leg bioimpedance

    OpenAIRE

    Sung, R; Lau, P; Yu, C; Lam, P; Nelson, E

    2001-01-01

    AIMS—(1) To validate a leg to leg bioimpedance analysis (BIA) device in the measurement of body composition in children by assessment of its agreement with dual energy x ray absorptiometry (DXA) and its repeatability. (2) To establish a reference range of percentage body fat in Hong Kong Chinese children.
METHODS—Sequential BIA and DXA methods were used to determine body composition in 49 children aged 7-18 years; agreement between the two methods was calculated. Repea...

  14. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect–machine hybrid legged robot). PMID:25140875

  15. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  16. Design of a Quasi-Passive Parallel Leg Exoskeleton to Augment Load Carrying for Walking

    National Research Council Canada - National Science Library

    Valiente, Andrew

    2005-01-01

    .... The exoskeleton structure runs parallel to the legs, transferring payload forces to the ground. In an attempt to make the exoskeleton more efficient, passive hip and ankle springs are employed to store and release energy throughout the gait cycle...

  17. Leg stiffness during sprinting in transfemoral amputees with running-specific prosthesis.

    Science.gov (United States)

    Sano, Yoko; Makimoto, Atsushi; Hashizume, Satoru; Murai, Akihiko; Kobayashi, Yoshiyuki; Takemura, Hiroshi; Hobara, Hiroaki

    2017-07-01

    Carbon fiber running-specific prostheses are designed to reproduce the spring-like stepping behavior of individuals similar to springs loaded by the entire body mass (i.e. spring-mass model). The aim of this study was to test whether leg stiffness would be modulated differently between intact and prosthetic legs in transfemoral amputees wearing RSP during sprinting. Eight unilateral transfemoral amputees performed maximum sprinting along an indoor overground runway. Leg stiffness was calculated from kinetic and kinematic data in intact and prosthetic legs. The results showed that leg stiffness was for the prosthetic limb approximately 12% decreased compared to the intact limb. Although there was no difference in leg compression between the legs, maximal vertical ground reaction force was significantly greater in the intact leg than in the prosthetic one. These results indicate that asymmetric modulation of leg stiffness in transfemoral amputees with running-specific prostheses is mainly associated with asymmetric ground reaction force. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Gait Planning Research for an Electrically Driven Large-Load-Ratio Six-Legged Robot

    Directory of Open Access Journals (Sweden)

    Hong-Chao Zhuang

    2017-03-01

    Full Text Available Gait planning is an important basis for the walking of a legged robot. To improve the walking stability of multi-legged robots and to reduce the impact force between the foot and the ground, gait planning strategies are presented for an electrically driven large-load-ratio six-legged robot. First, the configuration and walking gait of the electrically driven large-load-ratio six-legged robot are designed. The higher-stable swing sequences of legs and typical walking modes are respectively obtained. Based on the Denavit–Hartenberg (D–H method, the analyses of the forward and inverse kinematics are implemented. The mathematical models of the articulated rotation angles are respectively established. In view of the buffer device installed at the end of shin to decrease the impact force between the foot and the ground, an initial lift height of the leg is brought into gait planning when the support phase changes into the transfer phase. The mathematical models of foot trajectories are established. Finally, a prototype of the electrically driven large-load-ratio six-legged robot is developed. The experiments of the prototype are carried out regarding the aspects of the walking speed and surmounting obstacle. Then, the reasonableness of gait planning is verified based on the experimental results. The proposed strategies of gait planning lay the foundation for effectively reducing the foot–ground impact force and can provide a reference for other large-load-ratio multi-legged robots.

  19. Whole-body 3D kinematics of bird take-off: key role of the legs to propel the trunk

    Science.gov (United States)

    Provini, Pauline; Abourachid, Anick

    2018-02-01

    Previous studies showed that birds primarily use their hindlimbs to propel themselves into the air in order to take-off. Yet, it remains unclear how the different parts of their musculoskeletal system move to produce the necessary acceleration. To quantify the relative motions of the bones during the terrestrial phase of take-off, we used biplanar fluoroscopy in two species of birds, diamond dove ( Geopelia cuneata) and zebra finch ( Taeniopygia guttata). We obtained a detailed 3D kinematics analysis of the head, the trunk and the three long bones of the left leg. We found that the entire body assisted the production of the needed forces to take-off, during two distinct but complementary phases. The first one, a relatively slow preparatory phase, started with a movement of the head and an alignment of the different groups of bones with the future take-off direction. It was associated with a pitch down of the trunk and a flexion of the ankle, of the hip and, to a lesser extent, of the knee. This crouching movement could contribute to the loading of the leg muscles and store elastic energy that could be released in the propulsive phase of take-off, during the extension of the leg joints. Combined with the fact that the head, together with the trunk, produced a forward momentum, the entire body assisted the production of the needed forces to take-off. The second phase was faster with mostly horizontal forward and vertical upward translation motions, synchronous to an extension of the entire lower articulated musculoskeletal system. It led to the propulsion of the bird in the air with a fundamental role of the hip and ankle joints to move the trunk upward and forward. Take-off kinematics were similar in both studied species, with a more pronounced crouching movement in diamond dove, which can be related to a large body mass compared to zebra finch.

  20. Characterizing rapid-onset vasodilation to single muscle contractions in the human leg

    Science.gov (United States)

    Credeur, Daniel P.; Holwerda, Seth W.; Restaino, Robert M.; King, Phillip M.; Crutcher, Kiera L.; Laughlin, M. Harold; Padilla, Jaume

    2014-01-01

    Rapid-onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their maximum voluntary contraction (MVC) using isometric knee extension made with the leg above and below heart level, and these were compared with single isometric contractions of the forearm (handgrip). Single thigh cuff compressions (300 mmHg) were utilized to estimate the mechanical contribution to leg ROV. Continuous blood flow was determined by duplex-Doppler ultrasound and blood pressure via finger photoplethysmography (Finometer). Single isometric knee extensor contractions produced intensity-dependent increases in peak leg vascular conductance that were significantly greater than the forearm in both the above- and below-heart level positions (e.g., above heart level: leg 20% MVC, +138 ± 28% vs. arm 20% MVC, +89 ± 17%; P leg. Collectively, these data demonstrate the presence of a rapid and robust vasodilation to single muscle contractions in the leg that is largely independent of mechanical factors, thus establishing the leg as a viable model to study ROV in humans. PMID:25539935

  1. Leg pain and gynecologic malignancy.

    Science.gov (United States)

    Singh, Lilly; Stevens, Erin E

    2013-09-01

    Gynecologic malignancies affect more than 83 000 women in the United States, each year. Because the disease involves the pelvis, many patients have side effects distal to this area in their lower extremities. The differential diagnosis of leg pain can be divided into vascular, neurologic, and musculoskeletal causes. In this review article, we address numerous etiologies of leg pain, reviewing the prevalence of disease, physical examination findings, diagnostic as well as treatment modalities.

  2. Restless legs syndrome (RLS) with expansion of symptoms to the face.

    Science.gov (United States)

    Buchfuhrer, Mark J

    2008-01-01

    It has been well established that restless legs syndrome (RLS) manifests with symptoms most frequently in the legs followed by the arms. Other body parts may be affected but it has been somewhat controversial as to whether symptoms may extend to the face. We are reporting two cases of RLS showing unusual extension of symptoms. These two patients presented with symptoms which extended to body parts beyond the legs, including to the face. The facial symptoms can be relieved by walking, massage or medication. It is important to be aware of unusual extension of symptoms either as progression of the disease or as manifestation of augmentation.

  3. Restless Legs Syndrome and Leg Motor Restlessness in Parkinson's Disease.

    Science.gov (United States)

    Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi

    2015-01-01

    Sleep disturbances are important nonmotor symptoms in Parkinson's disease (PD) that are associated with a negative impact on quality of life. Restless legs syndrome (RLS), which is characterized by an urge to move the legs accompanied by abnormal leg sensations, can coexist with PD, although the pathophysiology of these disorders appears to be different. RLS and PD both respond favorably to dopaminergic treatment, and several investigators have reported a significant relationship between RLS and PD. Sensory symptoms, pain, motor restlessness, akathisia, and the wearing-off phenomenon observed in PD should be differentiated from RLS. RLS in PD may be confounded by chronic dopaminergic treatment; thus, more studies are needed to investigate RLS in drug-naïve patients with PD. Recently, leg motor restlessness (LMR), which is characterized by an urge to move the legs that does not fulfill the diagnostic criteria for RLS, has been reported to be observed more frequently in de novo patients with PD than in age-matched healthy controls, suggesting that LMR may be a part of sensorimotor symptoms intrinsic to PD. In this paper, we provide an overview of RLS, LMR, and PD and of the relationships among these disorders.

  4. Leg 179 summary

    Digital Repository Service at National Institute of Oceanography (India)

    Pettigrew, T.J.; Casey, J.F.; Miller, D.J.; Araki, E.; Boissonnas, R.; Busby, R.; Einaudi, F.; Gerdom, M.; Guo, Z.P.; Hopkins, H.; Myers, G.; Rao, D.G.; Shibata, T.; Thy, P.

    on the east rim of the Atlantis II Fracture Zone, ~200 m northwest of Hole 735B (32°43.32′S, 57°15.85′E; Fig. F2). This site was selected based on a video survey beginning at Hole 735B, by which we sought to find a reasonably flat, large outcrop to initiate... of the system. A frequency analyzer for monitoring hammer operations was built and installed during the transit. After a 4-hr video survey starting at the Hole 735B guide base, we selected a location with extensive, relatively flat-appearing outcrop and set...

  5. Influence of “J”-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion

    Directory of Open Access Journals (Sweden)

    Runxiao Wang

    2016-01-01

    Full Text Available Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of “J”-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with “J”-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with “J”-curve spring stiffness reveals that (1 both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2 at fast running speed from 25 to 40/92 m s−1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with “J”-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

  6. Influence of "J"-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion.

    Science.gov (United States)

    Wang, Runxiao; Zhao, Wentao; Li, Shujun; Zhang, Shunqi

    2016-01-01

    Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of "J"-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with "J"-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with "J"-curve spring stiffness reveals that (1) both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2) at fast running speed from 25 to 40/92 m s -1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with "J"-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

  7. Restless legs syndrome and periodic leg movements of sleep.

    Science.gov (United States)

    Rye, David B; Trotti, Lynn Marie

    2012-11-01

    Women are more commonly affected than men by restless legs syndrome, and prevalence is highest amongst those of northern European heritage. The motor manifestations include nonvolitional myoclonus (periodic leg movements). Disinhibition of spinal sensorimotor circuits may underlie these primary features and can be affected by peripheral as well as supraspinal networks. Insufficient mobilizable iron stores increase expressivity in some individuals. The sensorimotor features are relieved by dopamine, especially dopamine agonists, gabapentin and its derivatives, and opioids. A diagnosis relies on recognition of key primary and supportive features, and treatments are generally well tolerated, efficacious, and life-changing. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Promethus Hot Leg Piping Concept

    International Nuclear Information System (INIS)

    AM Girbik; PA Dilorenzo

    2006-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept

  9. Leg ulcers due to hyperhomocysteinemia

    Directory of Open Access Journals (Sweden)

    Krupa Shankar D

    2006-01-01

    Full Text Available Chronic leg ulcers are rare in young adults and generally indicate a vascular cause. We report a case of a 26-year-old man with leg ulcers of eight months duration. Doppler study indicated venous incompetence and a postphlebitic limb. However, as the distribution and number of ulcers was not consistent with stasis alone and no features of collagen vascular disease were noted, a hyperviscosity state was considered and confirmed with significantly elevated homocysteine level in the serum. Administration of vitamins B1, B2, B6 and B12, trimethyl-glycine, mecobalamine, folic acid and povidone iodine dressings with culture-directed antibiotic therapy led to a satisfactory healing of ulcers over a period of one month. Hyperhomocysteinemia must be considered in the differential diagnosis of leg ulcers in young individuals.

  10. Running over unknown rough terrain with a one-legged planar robot

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Ben; Miller, Bruce; Clark, Jonathan E [Department of Mechanical Engineering, Florida State University, Tallahassee, FL 32310 (United States); Schmitt, John, E-mail: clarkj@eng.fsu.edu [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331 (United States)

    2011-06-15

    The ability to traverse unknown, rough terrain is an advantage that legged locomoters have over their wheeled counterparts. However, due to the complexity of multi-legged systems, research in legged robotics has not yet been able to reproduce the agility found in the animal kingdom. In an effort to reduce the complexity of the problem, researchers have developed single-legged models to gain insight into the fundamental dynamics of legged running. Inspired by studies of animal locomotion, researchers have proposed numerous control strategies to achieve stable, one-legged running over unknown, rough terrain. One such control strategy incorporates energy variations into the system during the stance phase by changing the force-free leg length as a sinusoidal function of time. In this research, a one-legged planar robot capable of implementing this and other state-of-the-art control strategies was designed and built. Both simulated and experimental results were used to determine and compare the stability of the proposed controllers as the robot was subjected to unknown drop and raised step perturbations equal to 25% of the nominal leg length. This study illustrates the relative advantages of utilizing a minimal-sensing, active energy removal control scheme to stabilize running over rough terrain.

  11. Running over unknown rough terrain with a one-legged planar robot

    International Nuclear Information System (INIS)

    Andrews, Ben; Miller, Bruce; Clark, Jonathan E; Schmitt, John

    2011-01-01

    The ability to traverse unknown, rough terrain is an advantage that legged locomoters have over their wheeled counterparts. However, due to the complexity of multi-legged systems, research in legged robotics has not yet been able to reproduce the agility found in the animal kingdom. In an effort to reduce the complexity of the problem, researchers have developed single-legged models to gain insight into the fundamental dynamics of legged running. Inspired by studies of animal locomotion, researchers have proposed numerous control strategies to achieve stable, one-legged running over unknown, rough terrain. One such control strategy incorporates energy variations into the system during the stance phase by changing the force-free leg length as a sinusoidal function of time. In this research, a one-legged planar robot capable of implementing this and other state-of-the-art control strategies was designed and built. Both simulated and experimental results were used to determine and compare the stability of the proposed controllers as the robot was subjected to unknown drop and raised step perturbations equal to 25% of the nominal leg length. This study illustrates the relative advantages of utilizing a minimal-sensing, active energy removal control scheme to stabilize running over rough terrain.

  12. The development and evaluation of a program for leg-strengthening exercises and balance assessment using Kinect

    OpenAIRE

    Choi, Jin-Seung; Kang, Dong-Won; Seo, Jeong-Woo; Kim, Dae-Hyeok; Yang, Seung-Tae; Tack, Gye-Rae

    2016-01-01

    [Purpose] In this study, a program was developed for leg-strengthening exercises and balance assessment using Microsoft Kinect. [Subjects and Methods] The program consists of three leg-strengthening exercises (knee flexion, hip flexion, and hip extension) and the one-leg standing test (OLST). The program recognizes the correct exercise posture by comparison with the range of motion of the hip and knee joints and provides a number of correct action examples to improve training. The program mea...

  13. Cross-legged Gods and One-legged Foresters

    NARCIS (Netherlands)

    Petrovskaia, N.I.

    The present article is a re-evaluation of a marvellous element in a medieval Welsh romance, Chwedl Iarlles y Ffynnawn ‘Tale of the Lady of the Fountain’, also known as Owein. One of the characters encountered by the hero is a one-eyed one-legged dark giant forester who appears to have a particular

  14. The one-leg standing radiograph

    OpenAIRE

    Pinsornsak, P.; Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis wa...

  15. Alterations to the orientation of the ground reaction force vector affect sprint acceleration performance in team sports athletes.

    Science.gov (United States)

    Bezodis, Neil E; North, Jamie S; Razavet, Jane L

    2017-09-01

    A more horizontally oriented ground reaction force vector is related to higher levels of sprint acceleration performance across a range of athletes. However, the effects of acute experimental alterations to the force vector orientation within athletes are unknown. Fifteen male team sports athletes completed maximal effort 10-m accelerations in three conditions following different verbal instructions intended to manipulate the force vector orientation. Ground reaction forces (GRFs) were collected from the step nearest 5-m and stance leg kinematics at touchdown were also analysed to understand specific kinematic features of touchdown technique which may influence the consequent force vector orientation. Magnitude-based inferences were used to compare findings between conditions. There was a likely more horizontally oriented ground reaction force vector and a likely lower peak vertical force in the control condition compared with the experimental conditions. 10-m sprint time was very likely quickest in the control condition which confirmed the importance of force vector orientation for acceleration performance on a within-athlete basis. The stance leg kinematics revealed that a more horizontally oriented force vector during stance was preceded at touchdown by a likely more dorsiflexed ankle, a likely more flexed knee, and a possibly or likely greater hip extension velocity.

  16. Back Pain with Leg Pain.

    Science.gov (United States)

    Vulfsons, Simon; Bar, Negev; Eisenberg, Elon

    2017-07-01

    The clinical diagnostic dilemma of low back pain that is associated with lower limb pain is very common. In relation to back pain that radiates to the leg, the International Association for the Study of Pain (IASP) states: "Pain in the lower limb should be described specifically as either referred pain or radicular pain. In cases of doubt no implication should be made and the pain should be described as pain in the lower limb." Bogduks' editorial in the journal PAIN (2009) helps us to differentiate and define the terms somatic referred pain, radicular pain, and radiculopathy. In addition, there are other pathologies distal to the nerve root that could be relevant to patients with back pain and leg pain such as plexus and peripheral nerve involvement. Hence, the diagnosis of back pain with leg pain can still be challenging. In this article, we present a patient with back and leg pain. The patient appears to have a radicular pain syndrome, but has no neurological impairment and shows signs of myofascial involvement. Is there a single diagnosis or indeed two overlapping syndromes? The scope of our article encompasses the common diagnostic possibilities for this type of patient. A discussion of treatment is beyond the scope of this article and depends on the final diagnosis/diagnoses made.

  17. Kan leg skabe fremtidens vindere?

    DEFF Research Database (Denmark)

    Holm, Claus

    2006-01-01

    Dansk Boldspil Union skruer ned for den præstationsorienterede tilgang til børnefodbold. I stedet skal børnenes leg med bolden i fokus. Målet er at forhindre massivt frafald i børne- og ungdomsfodbolden og højne niveauet hos topspillerne....

  18. Doppler ultrasound exam of an arm or leg

    Science.gov (United States)

    Peripheral vascular disease - Doppler; PVD - Doppler; PAD - Doppler; Blockage of leg arteries - Doppler; Intermittent claudication - Doppler; Arterial insufficiency of the legs - Doppler; Leg pain and ...

  19. Asymmetrical stabilization and mobilization exploited during static single leg stance and goal directed kicking.

    Science.gov (United States)

    King, Adam C; Wang, Zheng

    2017-08-01

    The motor control properties of the right and left legs are dependent on the stabilization and mobilization features of the motor tasks. The current investigation examined the right and left leg control differences - interlateral asymmetries - during static single leg stance and dynamic goal directed kicking with an emphasis of the asymmetrical stabilization and mobilization components of movements. Ten young, healthy, right-leg preferred individuals with minimal kicking experience completed both tests on each limb. During static single leg stance, participants were requested to stand as still as possible with one leg in contact with a force platform. Interlateral asymmetries of the standing leg were quantified using postural variability measures of the center of pressure (COP) standard deviation in the anterior-posterior (SD-COP AP ) and medial-lateral (SD-COP ML ) directions, resultant COP length and velocity, and 95% COP elliptical area. During dynamic goal directed kicking, participants stood on two adjacent force platforms in a side-by-side foot position and kicked a soccer ball toward three different directions as soon as they received an auditory cue of kicking. Three targets were located -30°, 0° or 30° in front and 3.05 m away from the participants' midline. Participants kicked the ball toward the targets with each of their feet. The vertical ground reaction force (vGRF) of the kicking leg was used to define the preparation (from above two standard deviations of vGRF baseline to toe-off) and swing (from toe-off to toe-return) phases of dynamic kicking. To determine the presence of interlateral asymmetries during dynamic kicking, the magnitude and timing of the anticipatory postural adjustments (APA) during the preparation phase of kicking were quantified using the lateral net COP (COPnet-ML) time series derived from both force platforms. Postural variability measures of the support leg and the kinematic joint range of motion (JROM) trajectories of the

  20. Leg tissue composition and physico-chemical parameters of sheep meat fed annatto coproduct

    Directory of Open Access Journals (Sweden)

    Dorgival Morais de Lima Júnior

    2017-10-01

    Full Text Available Our objective was to evaluate leg tissue composition and physico-chemical quality parameters of sheep meat fed with increasing levels of annatto coproduct. 32 male uncastrated animals without a defined breed were randomized in four treatments (0, 100, 200 and 300 g kg-1 of annatto coproduct in the DM diet. After 78 days of confinement, the animals were slaughtered and body components were recorded. Reconstituted leg weight, total muscle weight, biceps weight and semitendinosus weight showed a negative linear behavior (P 0.05 were found for leg tissue composition (%, muscle:bone ratio, relative fat or leg muscle. Meat physico-chemical parameters (color, shear force, water retention capacity and cooking losses were not affected by the inclusion of the annatto coproduct in the diet. The annatto coproduct can be included in up to 300 g kg-1 of dietary dry matter without negative effects to the leg tissue composition (% and physical parameters of confined sheep meat.

  1. A legged anchoring mechanism for capsule endoscopes using micropatterned adhesives.

    Science.gov (United States)

    Glass, Paul; Cheung, Eugene; Sitti, Metin

    2008-12-01

    This paper presents a new concept for an anchoring mechanism to enhance existing capsule endoscopes. The mechanism consists of three actuated legs with compliant feet lined with micropillar adhesives to be pressed into the intestine wall to anchor the device at a fixed location. These adhesive systems are inspired by gecko and beetle foot hairs. Single-leg and full capsule mathematical models of the forces generated by the legs are analyzed to understand capsule performance. Empirical friction models for the interaction of the adhesives with an intestinal substrate were experimentally determined in vitro using dry and oil-coated elastomer micropillar arrays with 140 microm pillar diameter, 105 microm spacing between pillars, and an aspect ratio of 1:1 on fresh porcine small intestine specimens. Capsule prototypes were also tested in a simulated intestine environment and compared with predicted peristaltic loads to assess the viability of the proposed design. The experimental results showed that a deployed 10 gr capsule robot can withstand axial peristaltic loads and anchor reliably when actuation forces are greater than 0.27 N using dry micropillars. Required actuation forces may be reduced significantly by using micropillars coated with a thin silicone oil layer.

  2. Algorithms for the diagnosis and treatment of restless legs syndrome in primary care

    Directory of Open Access Journals (Sweden)

    Monti Giorgio

    2011-02-01

    Full Text Available Abstract Background Restless legs syndrome (RLS is a neurological disorder with a lifetime prevalence of 3-10%. in European studies. However, the diagnosis of RLS in primary care remains low and mistreatment is common. Methods The current article reports on the considerations of RLS diagnosis and management that were made during a European Restless Legs Syndrome Study Group (EURLSSG-sponsored task force consisting of experts and primary care practioners. The task force sought to develop a better understanding of barriers to diagnosis in primary care practice and overcome these barriers with diagnostic and treatment algorithms. Results The barriers to diagnosis identified by the task force include the presentation of symptoms, the language used to describe them, the actual term "restless legs syndrome" and difficulties in the differential diagnosis of RLS. Conclusion The EURLSSG task force reached a consensus and agreed on the diagnostic and treatment algorithms published here.

  3. Algorithms for the diagnosis and treatment of restless legs syndrome in primary care.

    Science.gov (United States)

    Garcia-Borreguero, Diego; Stillman, Paul; Benes, Heike; Buschmann, Heiner; Chaudhuri, K Ray; Gonzalez Rodríguez, Victor M; Högl, Birgit; Kohnen, Ralf; Monti, Giorgio Carlo; Stiasny-Kolster, Karin; Trenkwalder, Claudia; Williams, Anne-Marie; Zucconi, Marco

    2011-02-27

    Restless legs syndrome (RLS) is a neurological disorder with a lifetime prevalence of 3-10%. in European studies. However, the diagnosis of RLS in primary care remains low and mistreatment is common. The current article reports on the considerations of RLS diagnosis and management that were made during a European Restless Legs Syndrome Study Group (EURLSSG)-sponsored task force consisting of experts and primary care practitioners. The task force sought to develop a better understanding of barriers to diagnosis in primary care practice and overcome these barriers with diagnostic and treatment algorithms. The barriers to diagnosis identified by the task force include the presentation of symptoms, the language used to describe them, the actual term "restless legs syndrome" and difficulties in the differential diagnosis of RLS. The EURLSSG task force reached a consensus and agreed on the diagnostic and treatment algorithms published here.

  4. Unilateral eccentric contraction of the plantarflexors leads to bilateral alterations in leg dexterity

    Directory of Open Access Journals (Sweden)

    Akira Nagamori

    2016-11-01

    Full Text Available Eccentric contractions can affect musculotendon mechanical properties and disrupt muscle proprioception, but their behavioral consequences are poorly understood. We tested whether repeated eccentric contractions of plantarflexor muscles of one leg affected the dexterity of either leg. Twenty healthy male subjects (27.3+/-4.0 yrs compressed a compliant and slender spring prone to buckling with each isolated leg. The maximal instability they could control (i.e., the maximal average sustained compression force, or lower extremity dexterity force, LEDForce quantified the dexterity of each leg. We found that eccentric contractions did not affect LEDForce, but reduced force variability (LEDSD. Surprisingly, LEDForce increased in the non-exposed, contralateral leg. These effects were specific to exposure to eccentric contractions because an effort-matched exposure to walking did not affect leg dexterity. In the exposed leg, eccentric contractions (i reduced voluntary error corrections during spring compressions (i.e., reduced 0.5-4 Hz power of LEDForce; (ii did not change spinal excitability (i.e., unaffected H-reflexes; and (iii changed the structure of the neural drive to the alpha-motoneuron pool (i.e., reduced EMG power within the 4-8 Hz physiological tremor band. These results suggest that repeated eccentric contractions alter the feedback control for dexterity in the exposed leg by reducing muscle spindle sensitivity. Moreover, the unexpected improvement in LEDForce in the non-exposed contralateral leg was likely a consequence of crossed-effects on its spinal and supraspinal feedback control. We discuss the implications of these bilateral effects of unilateral eccentric contractions, their effect on spinal and supraspinal control of dynamic foot-ground interactions, and their potential to facilitate rehabilitation from musculoskeletal and neuromotor impairments.

  5. Trunk orientation causes asymmetries in leg function in small bird terrestrial locomotion.

    Science.gov (United States)

    Andrada, Emanuel; Rode, Christian; Sutedja, Yefta; Nyakatura, John A; Blickhan, Reinhard

    2014-12-22

    In contrast to the upright trunk in humans, trunk orientation in most birds is almost horizontal (pronograde). It is conceivable that the orientation of the heavy trunk strongly influences the dynamics of bipedal terrestrial locomotion. Here, we analyse for the first time the effects of a pronograde trunk orientation on leg function and stability during bipedal locomotion. For this, we first inferred the leg function and trunk control strategy applied by a generalized small bird during terrestrial locomotion by analysing synchronously recorded kinematic (three-dimensional X-ray videography) and kinetic (three-dimensional force measurement) quail locomotion data. Then, by simulating quail gaits using a simplistic bioinspired numerical model which made use of parameters obtained in in vivo experiments with real quail, we show that the observed asymmetric leg function (left-skewed ground reaction force and longer leg at touchdown than at lift-off) is necessary for pronograde steady-state locomotion. In addition, steady-state locomotion becomes stable for specific morphological parameters. For quail-like parameters, the most common stable solution is grounded running, a gait preferred by quail and most of the other small birds. We hypothesize that stability of bipedal locomotion is a functional demand that, depending on trunk orientation and centre of mass location, constrains basic hind limb morphology and function, such as leg length, leg stiffness and leg damping. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  6. [Restless legs syndrome and nocturnal leg pain : Differential diagnosis and treatment].

    Science.gov (United States)

    Hornyak, M; Stiasny-Kolster, K; Evers, S; Happe, S

    2011-09-01

    Pain in the legs belongs to the five most frequent regional pain symptoms. Restless legs syndrome (RLS) presents a particular differential diagnosis for pain in the legs, which is characterized by a nocturnal urge to move the legs often associated with painful sensations in the legs. It is one of the most common neurological disorders and probably the leading cause of nocturnal pain in the legs. In this overview, the diagnosis and therapy of RLS as well as aspects of pain therapy of the disorder are presented. In addition, the differential diagnoses for exclusion of other specific causes of nocturnal pain in the legs are discussed.

  7. Relative Contribution of Arms and Legs in 30 s Fully Tethered Front Crawl Swimming

    Directory of Open Access Journals (Sweden)

    Pedro G. Morouço

    2015-01-01

    Full Text Available The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking. A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50 m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking. Estimated relative contributions of arm stroke and leg kicking were 70.3% versus 29.7% for males and 66.6% versus 33.4% for females, with 15.6% and 13.1% force deficits, respectively. To obtain higher velocities, male swimmers are highly dependent on the maximum forces they can exert with the arm stroke (r=0.77, P<0.01, whereas female swimmers swimming velocity is more related to whole-body mean forces (r=0.81, P<0.01. The obtained results point that leg kicking plays an important role over short duration high intensity bouts and that the used methodology may be useful to identify strength and/or coordination flaws.

  8. Relative Contribution of Arms and Legs in 30 s Fully Tethered Front Crawl Swimming.

    Science.gov (United States)

    Morouço, Pedro G; Marinho, Daniel A; Izquierdo, Mikel; Neiva, Henrique; Marques, Mário C

    2015-01-01

    The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female) randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking). A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50 m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking. Estimated relative contributions of arm stroke and leg kicking were 70.3% versus 29.7% for males and 66.6% versus 33.4% for females, with 15.6% and 13.1% force deficits, respectively. To obtain higher velocities, male swimmers are highly dependent on the maximum forces they can exert with the arm stroke (r = 0.77, P swimming velocity is more related to whole-body mean forces (r = 0.81, P < 0.01). The obtained results point that leg kicking plays an important role over short duration high intensity bouts and that the used methodology may be useful to identify strength and/or coordination flaws.

  9. [Compression therapy of chronic leg ulcers : Practical aspects].

    Science.gov (United States)

    Dissemond, J; Protz, K; Hug, J; Reich-Schupke, S; Kröger, K

    2017-02-16

    Compression therapy, together with modern moist wound treatment, is the basis for a successful conservative treatment of patients with chronic leg ulcers. In clinical practice, it is often the patients themselves who apply compression therapies. Many of the mostly elderly patients, however, are not able to reach their legs and feet due to movement restrictions, such as arthritis, arthrosis and even obesity. An adequate compression therapy also requires extensive experience and regular training. In practice only the minority of patients can perform bandaging well and therefore this should not be recommended. Self-management with do-it-yourself medical devices will become more and more important in the future. In addition to the psychological factors, cost aspects and demographic change, an expected lack of qualified nursing staff due to the number of elderly patients who are potentially in need of care means that self-management is becoming increasingly more important. For the essentially important compression therapy of patients with chronic leg ulcers, there already exist various therapy options. The needs, preferences and abilities of the patients concerned can be considered when selecting the appropriate system. Particularly for the self-management of compression therapy, adaptive compression bandages are suitable for patients with leg ulcers during the initial decompression phase and ulcer stocking systems in the subsequent maintenance phase.

  10. [Etiological diagnosis of leg ulcers].

    Science.gov (United States)

    Debure, Clélia

    2010-09-20

    Etiological diagnosis of leg ulcers must be the first step of treatment, even if we know that veinous disease is often present. We can build a clinical decisional diagram, which helps us to understand and not forget the other causes of chronic wounds and choose some basic examination, like ultrasound and histological findings. This diagnosis helps to choose the right treatment in order to cure even the oldest venous ulcers. Educational programs should be improved to prevent recurrence.

  11. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  12. Thick legs - not always lipedema.

    Science.gov (United States)

    Reich-Schupke, Stefanie; Altmeyer, Peter; Stücker, Markus

    2013-03-01

    Due to its increased presence in the press and on television, the diagnosis of lipedema is on the way to becoming a trendy diagnosis for those with thick legs. Despite this, one must recognize that lipedema is a very rare disease. It is characterized by disproportional obesity of the extremities, especially in the region of the hip and the legs, hematoma development after minimal trauma, and increased pressure-induced or spontaneous pain. Aids for making the correct diagnosis are (duplex) sonography, the waist-hip index or the waist-height index and lymphoscintigraphy. Important differential diagnoses are constitutional variability of the legs, lipohypertrophy in obesity, edema in immobility, edema in chronic venous insufficiency and rheumatic diseases. The symptom-based therapy of lipedema consists of conservative (compression, manual lymphatic drainage, exercise) and surgical treatments (liposuction). Until now there is no curative therapy. Obesity is an important risk factor for the severity and prognosis of lipedema. Further studies for a better understanding of the pathogenesis of lipedema and in the end possible curative treatments are urgently needed. © The Authors | Journal compilation © Blackwell Verlag GmbH, Berlin.

  13. Leg muscle power in 12-year-old black and white Tunisian football players.

    Science.gov (United States)

    Ben Ayed, Karim; Latiri, Imed; Dore, Eric; Tabka, Zouhair

    2011-04-01

    This study examined leg muscle power of young male Tunisian black and white football players and extended the analysis to determine whether there is a relationship between cycling peak power output (PPO) and some field tests. A total of 113 children (white group (WG) = n = 56; black group (BG) = n = 57) participated in this investigation. Anthropometric data included age, body mass (BM), height, leg length (LL), body mass index (BMI), and leg muscle volume (LMV). Cycling PPO was measured including a force-velocity test. Peak power output (PPO; W and W/kg), Fopt (optimal braking force), and Vopt (optimal velocity) were significantly higher in the WG compared with the BG (p force-velocity test as explanatory factors showed that 33% of the variance of PPO of BG was explained by qualitative factors that may be related to cycling skill, muscle composition, and socioeconomic and training status.

  14. Epilepsy and restless legs syndrome.

    Science.gov (United States)

    Geyer, James D; Geyer, Emery E; Fetterman, Zachary; Carney, Paul R

    2017-03-01

    Restless legs syndrome (RLS) is a common neurological movement disorder occurring in approximately 10% of the general population. The prevalence of moderately severe RLS is 2.7% overall (3.7% for women and 1.7% for men). Epilepsy is also a common neurological disorder with significant associated morbidity and impact on quality of life. We evaluated the severity and frequency of primary RLS in patients with localization-related temporal lobe epilepsy (TLE) and investigated the role of prodromal RLS symptoms as a warning sign and lateralizing indicator. All epilepsy patients seen in the outpatient clinic were screened for movement disorders from 2005 to 2015. Ninety-eight consecutive patients with localization-related TLE (50 right TLE and 48 left TLE) who met inclusion criteria were seen in the outpatient clinic. The control group consisted of 50 individuals with no history or immediate family history of epilepsy. Each patient was evaluated with the International Restless Legs Study Group (IRLSSG) questionnaire, NIH RLS diagnostic criteria, ferritin level, and comprehensive sleep screening including polysomnography. Furthermore, patients with obstructive sleep apnea or a definite cause of secondary restless legs syndrome such as low serum ferritin or serum iron levels were also excluded from the study. There was a significant association between the type of epilepsy and whether or not patients had RLS χ 2 (1)=10.17, prestlessness was typically described as moderately severe. The RLS symptoms were more common and somewhat more severe in the right TLE group than the left TLE group. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Quinine for Nocturnal Leg Cramps

    Science.gov (United States)

    Man-Son-Hing, Malcolm; Wells, George; Lau, Anita

    1998-01-01

    OBJECTIVE With respect to the use of quinine for the treatment of nocturnal leg cramps, to determine whether the findings of a previously performed meta-analysis of published data are altered with the addition of unpublished data, and whether publication bias is present in this area. DESIGN A meta-analysis of eight (four published and four unpublished) randomized, double-blind, placebo-controlled trials, seven of which had a crossover design. SETTING Randomized trials that were available as of July 1997. SUBJECTS Ambulatory patients (659) who suffered from regular nocturnal leg cramps. MAIN RESULTS When individual patient data from all crossover studies were pooled, persons had 3.60 (95% confidence interval [CI] 2.15, 5.05) fewer cramps in a 4-week period when taking quinine compared with placebo. This compared with an estimate of 8.83 fewer cramps (95% CI 4.16, 13.49) from pooling published studies alone. The corresponding relative risk reductions were 21% (95% CI 12%, 30%) and 43% (95% CI 21%, 65%), respectively. Compared with placebo, the use of quinine was associated with an increased incidence of side effects, particularly tinnitus. Publication bias is present in the reporting of the efficacy of quinine for this indication, as almost all published studies reported larger estimates of its efficacy than did unpublished studies. CONCLUSIONS This study confirms that quinine is efficacious in the prevention of nocturnal leg cramps. However, its benefit may not be as large as reported from the pooling of published studies alone. Given the side effect profile of quinine, nonpharmacologic therapy (e.g., regular passive stretching of the affected muscle) is the best first-line treatment. For persons who find this ineffective and whose quality of life is significantly affected, a trial of quinine is warranted. Prescribing physicians must closely monitor the risks and benefits in individual patients. Publication bias is present in this area even though there is

  16. Common mechanics of mode switching in locomotion of limbless and legged animals

    Science.gov (United States)

    Kuroda, Shigeru; Kunita, Itsuki; Tanaka, Yoshimi; Ishiguro, Akio; Kobayashi, Ryo; Nakagaki, Toshiyuki

    2014-01-01

    Crawling using muscular waves is observed in many species, including planaria, leeches, nemertea, aplysia, snails, chitons, earthworms and maggots. Contraction or extension waves propagate along the antero-posterior axis of the body as the crawler pushes the ground substratum backward. However, the observation that locomotory waves can be directed forward or backward has attracted much attention over the past hundred years. Legged organisms such as centipedes and millipedes exhibit parallel phenomena; leg tips form density waves that propagate backward or forward. Mechanical considerations reveal that leg-density waves play a similar role to locomotory waves in limbless species, and that locomotory waves are used by a mechanism common to both legged and limbless species to achieve crawling. Here, we report that both mode switching of the wave direction and friction control were achieved when backward motion was induced in the laboratory. We show that the many variations of switching in different animals can essentially be classified in two types according to mechanical considerations. We propose that during their evolution, limbless crawlers first moved in a manner similar to walking before legs were obtained. Therefore, legged crawlers might have learned the mechanical mode of movement involved in walking long before obtaining legs. PMID:24718452

  17. Effects of technique variations on knee biomechanics during the squat and leg press.

    Science.gov (United States)

    Escamilla, R F; Fleisig, G S; Zheng, N; Lander, J E; Barrentine, S W; Andrews, J R; Bergemann, B W; Moorman, C T

    2001-09-01

    The specific aim of this project was to quantify knee forces and muscle activity while performing squat and leg press exercises with technique variations. Ten experienced male lifters performed the squat, a high foot placement leg press (LPH), and a low foot placement leg press (LPL) employing a wide stance (WS), narrow stance (NS), and two foot angle positions (feet straight and feet turned out 30 degrees ). No differences were found in muscle activity or knee forces between foot angle variations. The squat generated greater quadriceps and hamstrings activity than the LPH and LPL, the WS-LPH generated greater hamstrings activity than the NS-LPH, whereas the NS squat produced greater gastrocnemius activity than the WS squat. No ACL forces were produced for any exercise variation. Tibiofemoral (TF) compressive forces, PCL tensile forces, and patellofemoral (PF) compressive forces were generally greater in the squat than the LPH and LPL, and there were no differences in knee forces between the LPH and LPL. For all exercises, the WS generated greater PCL tensile forces than the NS, the NS produced greater TF and PF compressive forces than the WS during the LPH and LPL, whereas the WS generated greater TF and PF compressive forces than the NS during the squat. For all exercises, muscle activity and knee forces were generally greater in the knee extending phase than the knee flexing phase. The greater muscle activity and knee forces in the squat compared with the LPL and LPH implies the squat may be more effective in muscle development but should be used cautiously in those with PCL and PF disorders, especially at greater knee flexion angles. Because all forces increased with knee flexion, training within the functional 0-50 degrees range may be efficacious for those whose goal is to minimize knee forces. The lack of ACL forces implies that all exercises may be effective during ACL rehabilitation.

  18. Leg fluid accumulation during prolonged sitting.

    Science.gov (United States)

    Vena, Daniel; Rubianto, Jonathan; Popovic, Milos; Yadollahi, Azadeh

    2016-08-01

    The accumulation of fluid in the legs due to sedentariness can be a health risk in extreme cases. Negative health impacts associated with leg fluid accumulation include leg edema and risk of blood clots. Furthermore, fluid accumulating in the legs is accompanied by fluid shift into the upper body which is also associated with health risks such as: increased blood pressure when lying down, respiratory problems in people with heart failure, and increased sleep apnea. Understanding the pattern by which fluid accumulates in the legs can aid in the development of devices for reducing leg fluid accumulation. The purpose of this study was to characterize the time course of fluid accumulation over a two-and-half-hour seated period. Non-obese participants with sleep apnea and no other co-morbidities were included in the sample as part of a larger study. Leg fluid was measured continuously using a method of bioelectrical impedance. Participants were first asked to lie supine for 30 minutes as a washout, and then sat with their legs still for two and a half hours. The main finding of this study is that the pattern of leg fluid accumulation differed in the first 45 minutes compared to the latter 105 minutes. In the first 45 minutes, fluid accumulated according to first order exponential function. In the latter period, fluid accumulated according to a linear function. The initial exponential accumulation is likely due to the large increase in capillary pressure caused by rapid blood flow into the legs due to gravity, leading to substantial filtration of blood plasma into the tissue spaces. The latter linear portion likely represents continued slow filtration of fluid out of the vasculature and into the tissue spaces. This is the first study to show that fluid accumulation in the legs is a combination of an exponential and linear functions. The linear increase identifies that there is no foreseeable point in which leg fluid stops accumulating while sitting for prolonged periods.

  19. Twins Bed Rest Project: LBNP/Exercise Minimizes Changes in Lean Leg Mass, Strength and Endurance

    Science.gov (United States)

    Amorim, Fabiano T.; Schneider, Suzanne M.; Lee, Stuart M. C.; Boda, Wanda L.; Watenpaugh, Donald E.; Hargens, Alan R.

    2006-01-01

    Decreases in muscle strength and endurance frequently are observed in non-weightbearing conditions such as bed rest (BR), spaceflight or limb immobilization. Purpose: Ow purpose was to determine if supine treadmill exercise against simulated gravity, by application of lower body negative pressure (LBNP), prevents loss of lean leg mass, strength and endurance during 30 d of 6deg head-down bed rest (BR). Methods: Fifteen pairs of monozygous twins (8 male, 7 female pairs; 26+/-4 yrs; 170+/-12 cm; 62.6+/-11.3 kg; mean+/-SD) were subjects in the present study. One sibling of each pair of twins was randomly assigned to either an exercise (EX) or non-exercise (CON) group. The EX twin walked/jogged on a vertical treadmill within LBNP chamber 6 d/wk using a 40-min interval exercise protocol at 40-80% of pre-BR VO(sub 2peak). LBNP was adjusted individually for each subject such that footward force was between 1.0 and 1.2 times body weight (-53+/-5 mmHg LBNP). The CON twin performed no exercise during BR. Subjects performed isokinetic knee (60 and 120deg/s) and ankle (60deg/s) testing to assess strength and endurance (End) before and after BR. They also had their lean leg mass (L(sub mass)) evaluated by DEXA before and after BR. Results: Changes in peak torque (T(sub pk)) were smaller for flexion (flex) than for extension (ext) after BR and did not differ between groups. The CON group had larger decreases (P<0.05) in L(sub mass), knee and ankle ext T(sub pk), and knee ext End.

  20. Bio-inspired swing leg control for spring-mass robots running on ground with unexpected height disturbance.

    Science.gov (United States)

    Vejdani, H R; Blum, Y; Daley, M A; Hurst, J W

    2013-12-01

    We proposed three swing leg control policies for spring-mass running robots, inspired by experimental data from our recent collaborative work on ground running birds. Previous investigations suggest that animals may prioritize injury avoidance and/or efficiency as their objective function during running rather than maintaining limit-cycle stability. Therefore, in this study we targeted structural capacity (maximum leg force to avoid damage) and efficiency as the main goals for our control policies, since these objective functions are crucial to reduce motor size and structure weight. Each proposed policy controls the leg angle as a function of time during flight phase such that its objective function during the subsequent stance phase is regulated. The three objective functions that are regulated in the control policies are (i) the leg peak force, (ii) the axial impulse, and (iii) the leg actuator work. It should be noted that each control policy regulates one single objective function. Surprisingly, all three swing leg control policies result in nearly identical subsequent stance phase dynamics. This implies that the implementation of any of the proposed control policies would satisfy both goals (damage avoidance and efficiency) at once. Furthermore, all three control policies require a surprisingly simple leg angle adjustment: leg retraction with constant angular acceleration.

  1. Restless legs syndrome and periodic leg movements in patients with movement disorders: Specific considerations.

    Science.gov (United States)

    Högl, Birgit; Stefani, Ambra

    2017-05-01

    Restless legs syndrome is a frequent neurological disorder with potentially serious and highly distressing treatment complications. The role and potential implications of periodic leg movements during sleep range from being a genetic risk marker for restless legs syndrome to being a cardiovascular risk factor. The diagnosis of restless legs syndrome in patients with daytime movement disorders is challenging and restless legs syndrome needs to be differentiated from other sleep-related movement disorders. This article provides an update on the diagnosis of restless legs syndrome as an independent disorder and the role of periodic leg movements and reviews the association of restless legs syndrome with Parkinson's disease and other movement disorders. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

  2. Reliability of Single-Leg Balance and Landing Tests in Rugby Union; Prospect of Using Postural Control to Monitor Fatigue

    Directory of Open Access Journals (Sweden)

    Jordan C. Troester, Jason G. Jasmin, Rob Duffield

    2018-06-01

    Full Text Available The present study examined the inter-trial (within test and inter-test (between test reliability of single-leg balance and single-leg landing measures performed on a force plate in professional rugby union players using commercially available software (SpartaMARS, Menlo Park, USA. Twenty-four players undertook test – re-test measures on two occasions (7 days apart on the first training day of two respective pre-season weeks following 48h rest and similar weekly training loads. Two 20s single-leg balance trials were performed on a force plate with eyes closed. Three single-leg landing trials were performed by jumping off two feet and landing on one foot in the middle of a force plate 1m from the starting position. Single-leg balance results demonstrated acceptable inter-trial reliability (ICC = 0.60-0.81, CV = 11-13% for sway velocity, anterior-posterior sway velocity, and mediolateral sway velocity variables. Acceptable inter-test reliability (ICC = 0.61-0.89, CV = 7-13% was evident for all variables except mediolateral sway velocity on the dominant leg (ICC = 0.41, CV = 15%. Single-leg landing results only demonstrated acceptable inter-trial reliability for force based measures of relative peak landing force and impulse (ICC = 0.54-0.72, CV = 9-15%. Inter-test results indicate improved reliability through the averaging of three trials with force based measures again demonstrating acceptable reliability (ICC = 0.58-0.71, CV = 7-14%. Of the variables investigated here, total sway velocity and relative landing impulse are the most reliable measures of single-leg balance and landing performance, respectively. These measures should be considered for monitoring potential changes in postural control in professional rugby union.

  3. Leg stiffness during phases of countermovement and take-off in vertical jump.

    Science.gov (United States)

    Struzik, Artur; Zawadzki, Jerzy

    2013-01-01

    With respect to cyclic movements such as human gait, running or hopping, leg stiffness is a little variable parameter. The aim of this study was to investigate changes in leg stiffness during the phase of countermovement and take-off when performing a single maximum counter-movement jump. Kistler force plates and a BTS SMART system for comprehensive motion analysis were employed in the study. The study covered a group of 12 athletes from university basketball teams. Leg stiffness was calculated in those parts of countermovement and take-off phases where its level is relatively constant and the relationship F(Δl) is similar to linear one. Mean total stiffness (±SD) in both legs in the countermovement phase amounted to 6.5 ± 1.5 kN/m, whereas during the take-off phase this value was 6.9 ± 1 kN/m. No statistically significant differences were found between leg stiffness during the countermovement phase and takeoff phase in the study group at the level of significance set at α = 0.05. This suggests that the leg stiffness in phase of countermovement and phase of take-off are much similar to each other, despite different function of both phases. Similar to cyclic movements, leg stiffness turned out relatively constant when performing a single vertical jump. There are also reported statistically significant correlations between body mass, body height, length of lower limbs and leg stiffness. The stiffness analysed by the authors should be understood as quasi-stiffness because the measurements of ΔF(Δl) were made during transient states where inertia and dumping forces are likely to affect the final result.

  4. Restless legs syndrome mimicking S1 radiculopathy.

    Science.gov (United States)

    Zambelis, Th; Wolgamuth, B R; Papoutsi, S N; Economou, N T

    2016-01-01

    Α case of a chronic idiopathic form of a severe type of Restless Legs Syndrome (RLS), which developed during pregnancy and persisted after this, misdiagnosed for 34 years as radiculopathy S1, is reported. In spite of the thorough clinical and laboratory investigation, in addition to constant changes of the therapeutic approach, the diagnosis of S1 radiculopathy could not be confirmed, resulting in a chronic clinical course; the latter was characterized by relapses and remissions not attributed or linked in any way to the treatment (various types of). In fact, it was due to a routine workup in a sleep clinic, where the patient was referred because of a coincident chronic insomnia (Restless Legs Syndrome is a known and important cause of insomnia/chronic insomnia), which resulted in a proper diagnosis and treatment of this case. With the use of Restless Legs Syndrome appropriate treatment (Pramipexole 0.18 mg taken at bedtime, a dopaminergic agent and Level A recommended drug for Restless Legs Syndrome) an excellent response and immediate elimination of symptoms was achieved. Restless Legs Syndrome may present with a variety of symptoms (with the most prominent shortly being reported with the acronym URGE: Urge to move the legs usually associated with unpleasant leg sensations, Rest induces symptoms, Getting active brings relief, Evening and night deteriorate symptoms); given the fact that Restless Legs Syndrome presents with a great variety and heterogeneity of symptoms (mostly pain, dysesthesia and paresthesia), which may occur in several other diseases (the so called "RLS mimics"), proper diagnosis of Restless Legs Syndrome usually fails. Restless Legs Syndrome misinterpreted as S1 radiculopathy, to the best of our knowledge, has not been reported yet in the literature. Here, case history, clinical course and common RLS mimics are presented. Different forms of Restless Legs Syndrome manifestations, which are commonly -as in this case- misinterpreted due to their

  5. TRUNK LEAN DURING A SINGLE-LEG SQUAT IS ASSOCIATED WITH TRUNK LEAN DURING PITCHING.

    Science.gov (United States)

    Plummer, Hillary A; Oliver, Gretchen D; Powers, Christopher M; Michener, Lori A

    2018-02-01

    Impaired trunk motion during pitching may be a risk factor for upper extremity injuries. Specifically, increased forces about the shoulder and elbow have been observed in pitchers with excessive contralateral trunk lean during pitching. Because of the difficulty in identifying abnormal trunk motions during a high-speed task such as pitching, a clinical screening test is needed to identify pitchers who have impaired trunk motion during pitching. The purpose of this study was to determine the relationship between the degree of lateral trunk lean during the single-leg squat and amount of trunk lean during pitching and if trunk lean during pitching can be predicted from lean during the single-leg squat. Controlled Laboratory Study; Cross-sectional. Seventy-three young baseball pitchers (11.4 ± 1.7 years; 156.3 ± 11.9 cm; 50.5 ± 8.8 kg) participated. An electromagnetic tracking system was used to obtain trunk kinematic data during a single-leg squat task (lead leg) and at maximum shoulder external rotation of a fastball pitch. Pearson correlation coefficients for trunk lean during the single-leg squat and pitching were calculated. A linear regression analysis was performed to determine if trunk lean during pitching can be predicted from lean during the single-leg squat. There was a positive correlation between trunk lean during the single-leg squat and trunk lean during pitching (r = 0.53; plean during the single-leg squat predicted the amount of lateral trunk lean during pitching (R 2 = 0.28; p lean during an SLS and pitching. Trunk lean during the single-leg squat explained 28% of the variance in trunk lean during pitching. Diagnosis, level 3.

  6. Multiple joint muscle function with ageing: the force-velocity and power-velocity relationships in young and older men.

    Science.gov (United States)

    Allison, Sarah J; Brooke-Wavell, Katherine; Folland, Jonathan P

    2013-05-01

    Whilst extensive research has detailed the loss of muscle strength with ageing for isolated single joint actions, there has been little attention to power production during more functionally relevant multiple joint movements. The extent to which force or velocity are responsible for the loss in power with ageing is also equivocal. The aim of this study was to evaluate the contribution of force and velocity to the differences in power with age by comparing the force-velocity and power-velocity relationships in young and older men during a multiple joint leg press movement. Twenty-one older men (66 ± 3 years) and twenty-three young men (24 ± 2 years) completed a series of isometric (maximum and explosive) and dynamic contractions on a leg press dynamometer instrumented to record force and displacement. The force-velocity relationship was lower for the older men as reflected by their 19 % lower maximum isometric strength (p velocity relationship was lower for the older men as shown by reduced maximum power (-28 %, p velocity (-11 %, p velocity were lower in older men, the decrement in force was greater and therefore the major explanation for the attenuation of power during a functionally relevant multiple joint movement.

  7. Intensive treatment of leg lymphedema

    Directory of Open Access Journals (Sweden)

    Pereira de Godoy Jose

    2010-01-01

    Full Text Available Background: Despite of all the problems caused by lymphedema, this disease continues to affect millions of people worldwide. Thus, the identification of the most efficacious forms of treatment is necessary. Aim: The aim of this study was to evaluate a novel intensive outpatient treatment for leg lymphedema. Methods: Twenty-three legs of 19 patients were evaluated in a prospective randomized study. The inclusion criteria were patients with Grade II and III lymphedema, where the difference, measured by volumetry, between the affected limb below the knee and the healthy limb was greater than 1.5 kg. Intensive treatment was carried out for 6- to 8-h sessions in the outpatient clinic. Analysis of variance was utilized for statistical analysis with an alpha error of 5% (P-value < 0.05 being considered significant. Results: All limbs had significant reductions in size with the final mean loss being 81.1% of the volume of edema. The greatest losses occurred in the first week (P-value < 0.001. Losses of more than 90% of the lymphedema occurred in 9 (39.13% patients; losses of more than 80% in 13 (56.52%, losses of more than 70% in 17 (73.91% and losses of more than 50% were recorded for 95.65% of the patients; only 1 patient lost less than 50% (37.9% of the edema. Conclusion: The intensive treatment of lymphedema in the outpatient clinic can produce significant reductions in the volume of edema over a short period of time and can be recommended for any grade of lymphedema, in particular the more advanced degrees.

  8. Leg blood flow during static exercise.

    Science.gov (United States)

    Kilbom, A; Persson, J

    1982-01-01

    Leg blood flow was studied with the constant infusion dye technique during static exercise of the thigh muscles (quadriceps) and during hand-grips at 15 and 25-30% of MVC. Blood flow and oxygen uptake in the leg increased in quadriceps exercise and reached their highest values (around 1.21/min and 165 ml/min respectively) at 25-30% of MVC, whereas leg vascular resistance decreased. Regional circulatory adaptations and the oxygen uptake - leg blood flow relationship were in close agreement with the responses found in dynamic leg exercise. In view of the marked rise in intramuscular pressure previously observed during quadriceps contractions, a restriction of blood flow and an increased vascular resistance had been expected. Involuntary activation of leg muscles other than the quadriceps may explain the finding. Contractions of the contralateral quadriceps induced a slight increase in leg blood flow, whereas hand-grips had no influence on blood flow or vascular resistance in the leg. The distribution of the cardiac output during static contractions is discussed, and it is concluded that during hand-grips the increase in blood flow is predominantly distributed to the upper part of the body.

  9. Børns leg og eksperimenterende virksomhed

    DEFF Research Database (Denmark)

    Damgaard Warrer, Sarah; Broström, Stig

    Børns leg og eksperimenterende virksomhed er et rigt felt med mange perspektiver, indgangsvinkler og nuancer. I denne bog kædes leg og det eksperimenterende og skabende sammen som to gensidigt forbundne fænomener og belyses i pædagogisk og didaktisk perspektiv. Desuden beskrives potentialet i båd...

  10. TF Inner Leg Space Allocation for Pilot Plant Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    Peter H. Titus and Ali Zolfaghari

    2012-09-06

    A critical design feature of any tokamak is the space taken up by the inner leg of the toroidal field (TF) coil. The radial build needed for the TF inner leg, along with shield thickness , size of the central solenoid and plasma minor radius set the major radius of the machine. The cost of the tokamak core roughly scales with the cube of the major radius. Small reductions in the TF build can have a big impact on the overall cost of the reactor. The cross section of the TF inner leg must structurally support the centering force and that portion of the vertical separating force that is not supported by the outer structures. In this paper, the TF inner leg equatorial plane cross sections are considered. Out-of- Plane (OOP) forces must also be supported, but these are largest away from the equatorial plane, in the inner upper and lower corners and outboard sections of the TF coil. OOP forces are taken by structures that are not closely coupled with the radial build of the central column at the equatorial plane. The "Vertical Access AT Pilot Plant" currently under consideration at PPPL is used as a starting point for the structural, field and current requirements. Other TF structural concepts are considered. Most are drawn from existing designs such as ITER's circular conduits in radial plates bearing on a heavy nose section, and TPX's square conduits in a case, Each of these concepts can rely on full wedging, or partial wedging. Vaulted TF coils are considered as are those with some component of bucking against a central solenoid or bucking post. With the expectation that the pilot plant will be a steady state machine, a static stress criteria is used for all the concepts. The coils are assumed to be superconducting, with the superconductor not contributing to the structural strength. Limit analysis is employed to assess the degree of conservatism in the static criteria as it is applied to a linear elastic stress analysis. TF concepts, and in particular the PPPL AT

  11. Evaluation of Flexible Force Sensors for Pressure Monitoring in Treatment of Chronic Venous Disorders.

    Science.gov (United States)

    Parmar, Suresh; Khodasevych, Iryna; Troynikov, Olga

    2017-08-21

    The recent use of graduated compression therapy for treatment of chronic venous disorders such as leg ulcers and oedema has led to considerable research interest in flexible and low-cost force sensors. Properly applied low pressure during compression therapy can substantially improve the treatment of chronic venous disorders. However, achievement of the recommended low pressure levels and its accurate determination in real-life conditions is still a challenge. Several thin and flexible force sensors, which can also function as pressure sensors, are commercially available, but their real-life sensing performance has not been evaluated. Moreover, no researchers have reported information on sensor performance during static and dynamic loading within the realistic test conditions required for compression therapy. This research investigated the sensing performance of five low-cost commercial pressure sensors on a human-leg-like test apparatus and presents quantitative results on the accuracy and drift behaviour of these sensors in both static and dynamic conditions required for compression therapy. Extensive experimental work on this new human-leg-like test setup demonstrated its utility for evaluating the sensors. Results showed variation in static and dynamic sensing performance, including accuracy and drift characteristics. Only one commercially available pressure sensor was found to reliably deliver accuracy of 95% and above for all three test pressure points of 30, 50 and 70 mmHg.

  12. Active and Inactive Leg Hemodynamics during Sequential Single-Leg Interval Cycling.

    Science.gov (United States)

    Gordon, Nicole; Abbiss, Chris R; Ihsan, Mohammed; Maiorana, Andrew J; Peiffer, Jeremiah J

    2018-01-11

    Leg order during sequential single-leg cycling (i.e. exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. Ten young healthy adults (28 ± 6 y) completed six 1-min double-leg intervals interspersed with one minute of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with one minute of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume and power output were measured throughout each session. Oxygen consumption, heart rate and power output were not different between sets of single-leg intervals but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 mmHg vs. 104 ± 9 mmHg; p<0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 mmHg vs. 101 ± 10 mmHg; p<0.05). The increase in muscle blood volume from baseline was similar between the active single-leg and double-leg (267 ± 150 μM[BULLET OPERATOR]cm vs. 214 ± 169 μM[BULLET OPERATOR]cm; p=0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (p<0.05) when the leg was active in the initial (-52.3 ± 111.6%) compared with second set (65.1 ± 152.9%). These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.

  13. Peripheral artery bypass - leg - discharge

    Science.gov (United States)

    ... in the bath tub, a hot tub, or swimming pool. Ask your provider when you can start ... College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol . 2013; ...

  14. Principal component structure and sport-specific differences in the running one-leg vertical jump.

    Science.gov (United States)

    Laffaye, G; Bardy, B G; Durey, A

    2007-05-01

    The aim of this study is to identify the kinetic principal components involved in one-leg running vertical jumps, as well as the potential differences between specialists from different sports. The sample was composed of 25 regional skilled athletes who play different jumping sports (volleyball players, handball players, basketball players, high jumpers and novices), who performed a running one-leg jump. A principal component analysis was performed on the data obtained from the 200 tested jumps in order to identify the principal components summarizing the six variables extracted from the force-time curve. Two principal components including six variables accounted for 78 % of the variance in jump height. Running one-leg vertical jump performance was predicted by a temporal component (that brings together impulse time, eccentric time and vertical displacement of the center of mass) and a force component (who brings together relative peak of force and power, and rate of force development). A comparison made among athletes revealed a temporal-prevailing profile for volleyball players, and a force-dominant profile for Fosbury high jumpers. Novices showed an ineffective utilization of the force component, while handball and basketball players showed heterogeneous and neutral component profiles. Participants will use a jumping strategy in which variables related to either the magnitude or timing of force production will be closely coupled; athletes from different sporting backgrounds will use a jumping strategy that reflects the inherent demands of their chosen sport.

  15. Effect of leg length on ROM, VJ and leg dexterity in dance.

    Science.gov (United States)

    Wyon, M A; Nevill, A M; Dekker, K; Brown, D D; Clarke, F; Pelly, J; Koutedakis, Y

    2010-09-01

    We investigated the associations between leg length and specific ballet movements in different skill groups. Volunteers were from an undergraduate dance programme (n=18), a pre-professional school (n=43) and from an elite classical ballet company (n=45). Individual data were collected for anthropometry, vertical jump, leg dexterity, and leg active and passive ROM. ANCOVA identified both main effects as significant with regard to vertical jump (gender Peffects with gender, skill or leg length. Active and passive range of motion noted gender (P=0.001) and skill (Peffects of leg length on fundamental ballet skills. The longer legs that benefit vertical jump have a negative influence on range of motion and leg dexterity except for highly skilled dancers, who through skill, seem to have overcome the effects of some of these dichotomies. Georg Thieme Verlag KG Stuttgart . New York.

  16. The Comparing the Leg Muscles Electromyography during Single Leg Drop Landing in Pesplanus and Normal Men

    Directory of Open Access Journals (Sweden)

    mostafa bazvand

    2016-03-01

    Full Text Available Objective: pesplanus is one of the changes that brings about changes in muscle activation patterns. Being aware of muscles activity changes in various standing positions among pesplanus patients provides insights into preventing lower extremity injuries in this population. The aim of this study was to compare leg muscles electromyography during various standing positions in pesplanus and normal subjects. Methods: 60 healthy male university students, 30 subjects with pesplanus deformity (with average age 23/54±3/57 year, average height 175/34±7/62 cm, average weight 74/87±10/72 kg and 30 normal subjects (with average age 22/97±2/38 year, average height 176/6±5/59 cm, average weight 73/58±8/36 kg participated in this comparative study. Deformity of pesplanus was assessed with navicular drop test. Each subject performed single-leg landing dropping from 30cm height onto a force platform where muscles activity was recorded with EMG device. For data analysis, Matlab and Spss softwares were used and independent sample t-test was used to compare the dependent variables at a significance level of P &le 0/05. Results: Significant differences were observed between the two groups for the activities of the longus peroneus and anterior tibialis muscles ( p&le0/05 while no significant differences were observed in other muscles. Conclusion: The changes in the normal structure of the foot might affect muscle activities during standing, which can cause changes in the injury patterns. Therefore, it is proposed that focusing on corrective exercises and therapy plan can reduce these risks.

  17. Giant recurrent infantile myofi bromatosis of the leg in a 3 year-old ...

    African Journals Online (AJOL)

    Infantile myofi bromatosis is a rare mesenchymal disorder of infancy and childhood characterised by the formation of tumours in the soft tissues, muscles, bones and viscera. Only 61 cases have been reported in the literature. This paper describes the management of a 3 year-old boy with extensive IMF of the right leg.

  18. 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...

  19. Relation between subjective and objective scores on the active straight leg raising test.

    NARCIS (Netherlands)

    Pool-Goudzwaard, A.L.; Mens, Jan M A; Beekmans, RE; Tijhuis, MT

    2010-01-01

    DESIGN: Cross sectional. OBJECTIVE: To fill a gap in the validation of the active straight leg raising (ASLR) test concerning the relation between a patient's subjective score on the ASLR test and the objective measured force. SUMMARY OF BACKGROUND DATA: The ASLR test is used to classify patients

  20. Model-Based Experimental Development of Passive Compliant Robot Legs from Fiberglass Composites

    OpenAIRE

    Lin, Shang-Chang; Hu, Chia-Jui; Shih, Wen-Pin; Lin, Pei-Chun

    2015-01-01

    We report on the methodology of developing compliant, half-circular, and composite robot legs with designable stiffness. First, force-displacement experiments on flat cantilever composites made by one or multifiberglass cloths are executed. By mapping the cantilever mechanics to the virtual spring model, the equivalent elastic ...

  1. Controlling propulsive forces in gait initiation in transfemoral amputees

    NARCIS (Netherlands)

    van Keeken, Helco G.; Vrieling, Aline H.; Hof, At L.; Halbertsma, Jan P. K.; Schoppen, Tanneke; Postema, Klaas; Otten, Bert

    During prosthetic gait initiation, transfemoral (TF) amputees control the spatial and temporal parameters that modulate the propulsive forces, the positions of the center of pressure (CoP), and the center of mass (CoM). Whether their sound leg or the prosthetic leg is leading, the TF amputees reach

  2. Modelling equation of knee force during instep kicking using ...

    African Journals Online (AJOL)

    This paper presents the biomechanics analysis of the football players, to obtain the equation that relates with the variables and to get the force model equation when the kicking was made. The subjects delivered instep kicking by using the dominant's leg where one subjects using right and left leg. 2 Dimensional analysis ...

  3. Creatine supplementation enhances muscle force recovery after eccentrically-induced muscle damage in healthy individuals

    Directory of Open Access Journals (Sweden)

    Cribb Paul J

    2009-06-01

    Full Text Available Abstract Background Eccentric exercise-induced damage leads to reductions in muscle force, increased soreness, and impaired muscle function. Creatine monohydrate's (Cr ergogenic potential is well established; however few studies have directly examined the effects of Cr supplementation on recovery after damage. We examined the effects of Cr supplementation on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals. Methods Fourteen untrained male participants (22.1 ± 2.3 yrs, 173 ± 7.7 cm, 76.2 ± 9.3 kg were randomly separated into 2 supplement groups: i Cr and carbohydrate (Cr-CHO; n = 7; or ii carbohydrate (CHO; n = 7. Participants consumed their supplement for a period of 5 days prior to, and 14 days following a resistance exercise session. Participants performed 4 sets of 10 eccentric-only repetitions at 120% of their maximum concentric 1-RM on the leg press, leg extension and leg flexion exercise machine. Plasma creatine kinase (CK and lactate dehydrogenase (LDH activity were assessed as relevant blood markers of muscle damage. Muscle strength was examined by voluntary isokinetic knee extension using a Cybex dynamometer. Data were analyzed using repeated measures ANOVA with an alpha of 0.05. Results The Cr-supplemented group had significantly greater isokinetic (10% higher and isometric (21% higher knee extension strength during recovery from exercise-induced muscle damage. Furthermore, plasma CK activity was significantly lower (by an average of 84% after 48 hrs (P Conclusion The major finding of this investigation was a significant improvement in the rate of recovery of knee extensor muscle function after Cr supplementation following injury.

  4. Locomotor Adaptability Task Promotes Intense and Task-Appropriate Output From the Paretic Leg During Walking.

    Science.gov (United States)

    Clark, David J; Neptune, Richard R; Behrman, Andrea L; Kautz, Steven A

    2016-03-01

    To test the hypothesis that participants with stroke will exhibit appropriate increase in muscle activation of the paretic leg when taking a long step with the nonparetic leg compared to during steady-state walking, with a consequent increase in biomechanical output and symmetry during the stance phase of the modified gait cycle. Single-session observational study. Clinical research center in an outpatient hospital setting. Adults with chronic poststroke hemiparesis (N=15). Participants walked on an instrumented treadmill while kinetic, kinematic, and electromyogram data were recorded. Participants performed steady-state walking and a separate trial of the long-step adaptability task in which they were instructed to intermittently take a longer step with the nonparetic leg. Forward progression, propulsive force, and neuromuscular activation during walking. Participants performed the adaptability task successfully and demonstrated greater neuromuscular activation in appropriate paretic leg muscles, particularly increased activity in paretic plantarflexor muscles. Propulsion and forward progression by the paretic leg were also increased. These findings support the assertion that the nonparetic long-step task may be effective for use in poststroke locomotor rehabilitation to engage the paretic leg and promote recovery of walking. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. Severe Pelvic Obliquity Affects Femoral Offset in Patients with Total Hip Arthroplasty but Not Leg-Length Inequality

    OpenAIRE

    Zhou, Xiaoxiao; Wang, Qi; Zhang, Xianlong; Chen, Yunsu; Peng, Xiaochun; Mao, Yuanqing; Yang, Yang; Fu, Beigang; Wang, Xiuhui; Tang, Tingting

    2015-01-01

    Leg-length inequality is an extensively studied complication of total hip arthroplasty in normal patients. However, few studies have focused on the pelvic obliquity of coronal pelvic malrotation. We hypothesized that pelvic obliquity with a fixed abduction/adduction contracture deformity of the hip may intraoperatively affect the release of soft tissues, ultimately resulting in a leg-length inequality. This study also investigated whether the femoral and vertical offsets of total hip arthropl...

  6. Relation between peak knee flexion angle and knee ankle kinetics in single-leg jump landing from running: a pilot study on male handball players to prevent ACL injury.

    Science.gov (United States)

    Ameer, Mariam A; Muaidi, Qassim I

    2017-09-01

    The relationship between knee kinematics and knee-ankle kinetics during the landing phase of single leg jumping has been widely studied to identify proper strategies for preventing non-contact ACL injury. However, there is a lack of study on knee-ankle kinetics at peak knee flexion angle during jumping from running. Hence, the purpose of this study is to establish the relationship between peak knee flexion angle, knee extension moment, ankle plantar flexion moment and ground reaction force in handball players in order to protect ACL from excessive stress during single leg jumping. In addition, the study also clarifies the role of calf muscles in relieving part of ACL stresses with different knee flexion angles during landing. Fifteen active male elite handball players of Saudi Arabia have participated in this study (Age = 22.6 ± 3.5years, Height = 182 ± 3.7 cm, Weight = 87.5 ± 10.2 kg). The players performed three successful landings of single-leg jump following running a fixed distance of about 450cm. The data were collected using a 3D motion capture and analysis system (VICON). Pearson product moment correlation coefficients showed that greater peak knee flexion angle is related significantly to both lesser knee extension moment (r = -.623, P = .013) and vertical component of ground reaction force (VGRF) (r = -.688, P = .005) in landing phase. Moreover, increasing the peak knee flexion angle in landing phase tends to increase the ankle plantar flexion moment significantly (r = .832, P = .000). With an increase of the peak knee flexion angle during single leg jump landing from running, there would be less knee extension moment, low impact force and more plantar flexion moment. As such, the clinical implication of this study is that there may be a possible protective mechanism by increasing the knee flexion angle during landing phase, which tends to protect the ACL from vigorous strain and injuries.

  7. Hot Leg Piping Materials Issues

    International Nuclear Information System (INIS)

    V. Munne

    2006-01-01

    With Naval Reactors (NR) approval of the Naval Reactors Prime Contractor Team (NRPCT) recommendation to develop a gas cooled reactor directly coupled to a Brayton power conversion system as the space nuclear power plant (SNPP) for Project Prometheus (References a and b) the reactor outlet piping was recognized to require a design that utilizes internal insulation (Reference c). The initial pipe design suggested ceramic fiber blanket as the insulation material based on requirements associated with service temperature capability within the expected range, very low thermal conductivity, and low density. Nevertheless, it was not considered to be well suited for internal insulation use because its very high surface area and proclivity for holding adsorbed gases, especially water, would make outgassing a source of contaminant gases in the He-Xe working fluid. Additionally, ceramic fiber blanket insulating materials become very friable after relatively short service periods at working temperatures and small pieces of fiber could be dislodged and contaminate the system. Consequently, alternative insulation materials were sought that would have comparable thermal properties and density but superior structural integrity and greatly reduced outgassing. This letter provides technical information regarding insulation and materials issues for the Hot Leg Piping preconceptual design developed for the Project Prometheus space nuclear power plant (SNPP)

  8. Effects of a powered ankle-foot prosthesis on kinetic loading of the unaffected leg during level-ground walking

    OpenAIRE

    Grabowski, Alena M; D?Andrea, Susan

    2013-01-01

    Background People with a lower-extremity amputation that use conventional passive-elastic ankle-foot prostheses encounter a series of stress-related challenges during walking such as greater forces on their unaffected leg, and may thus be predisposed to secondary musculoskeletal injuries such as chronic joint disorders. Specifically, people with a unilateral transtibial amputation have an increased susceptibility to knee osteoarthritis, especially in their unaffected leg. Previous studies hav...

  9. A highly adaptive magnetorheological fluid robotic leg for efficient terrestrial locomotion

    Science.gov (United States)

    Jiang, Nan; Sun, Shuaishuai; Ouyang, Yiming; Xu, Min; Li, Weihua; Zhang, Shiwu

    2016-09-01

    To survive in nature, animals adjust the characteristics of their legs or fins to adapt the motion to their environment. Inspired by the locomotion of animals, a study on the tunable stiffness and damping of a leg will help in the development of intelligent locomotion robots. In this paper we report on the development and experiment of a novel and simple robotic leg that can be adapted to the environment via a smart magnetorheological fluid (MRF). The robotic leg consists of a rotation MRF damper, a torsional spring, a ‘foot’ and a ‘leg’. The curved part of the ‘foot’ makes contact with the grounds while the other end is linked to an outer cylinder of the MRF damper with an inelastic cable. The variable force arm rising from the MRF damper and the torsional spring can help the leg adapt to a changing environment. The characteristics of the MRF damper have been investigated and a model is built to describe its mechanical features when different currents are applied to the MRF damper. A test on a linear dynamic test instrument has been conducted to verify the accuracy of the model. The robotic leg is installed in a locomotion platform to investigate the speed of its locomotion and the cost of the transport; the result demonstrated the feasibility and adaptability of the leg when walking on hard terrain. Its simple structure, high adaptability, and easy control of the MRF leg helped in the design and development of a high performance field robot that can adapt to various environments.

  10. Passive Control of Attachment in Legged Space Robots

    Directory of Open Access Journals (Sweden)

    Alessandro Gasparetto

    2010-01-01

    Full Text Available In the space environment the absence of gravity calls for constant safe attachment of any loose object, but the low-pressure conditions prohibit the use of glue-type adhesives. The attachment system of freely hunting spiders, e.g. Evarcha arcuata, employs van der Waals forces and mechanical interlocking. Furthermore, detachment is achieved passively and requires little force. Hence, the spider serves as a model for a versatile legged robot for space applications, e.g. on the outer surface of a space station. In this paper, we analyse the dry attachment systems of E. arcuata and geckos as well as the kinematics of freely hunting spiders. We generalise the results of biological studies on spider locomotion and mobility, including the major movement and the position constraints set by the dry adhesion system. From these results, we define a simplified spider model and study the overall kinematics of the legs both in flight and in contact with the surface. The kinematic model, the data on spider gait characteristics and the adhesion constraints are implemented in a kinematic simulator. The simulator results confirm the principal functionality of our concept.

  11. Leg pain (Osgood-Schlatter) (image)

    Science.gov (United States)

    Leg pain in older children or young adolescents can occur for many reasons. An Osgood-Schlatter lesion results from continued trauma to the anterior tibial bone and causes a visible lump below the knee.

  12. Sturge-Weber syndrome - legs (image)

    Science.gov (United States)

    ... nervous system (neurocutaneous) and is associated with Port Wine Stain, red vascular markings on the face and other parts of the body (shown here on the legs). This is an unusual case, due to the large size of the lesion ( ...

  13. Leg or foot amputation - dressing change

    Science.gov (United States)

    ... patientinstructions/000018.htm Leg or foot amputation - dressing change To use the sharing features on this page, please enable JavaScript. You will need to change the dressing on your limb. This will help ...

  14. Conjoined legs: Sirenomelia or caudal regression syndrome?

    OpenAIRE

    Das, Sakti Prasad; Ojha, Niranjan; Ganesh, G Shankar; Mohanty, Ram Narayan

    2013-01-01

    Presence of single umbilical persistent vitelline artery distinguishes sirenomelia from caudal regression syndrome. We report a case of a12-year-old boy who had bilateral umbilical arteries presented with fusion of both legs in the lower one third of leg. Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting re...

  15. Efficiency and Speed in Legged Robots

    Science.gov (United States)

    2011-03-22

    which we substitute into (4.42) : ( -mv s J O=-km+ mvc -k __ c __ V v 2 c c 46 (4.43) (4.44) (4.45) (4.46) to fInd the switching curve m 3 s...Legged Mechanisms. IVSS. Traverse City, MI Muench, P., Alexander, J., Quinn, R., & Aschenbeck, K. (2005) Pneumatic Spring for Legged Walker. SPIE

  16. Flexural characteristics of a stack leg

    International Nuclear Information System (INIS)

    Cook, J.

    1979-06-01

    A 30 MV tandem Van de Graaff accelerator is at present under construction at Daresbury Laboratory. The insulating stack of the machine is of modular construction, each module being 860 mm in length. Each live section stack module contains 8 insulating legs mounted between bulkhead rings. The design, fabrication (from glass discs bonded to stainless steel discs using an epoxy film adhesive) and testing of the stack legs is described. (U.K.)

  17. Three-dimensional knee joint contact forces during walking in unilateral transtibial amputees.

    Science.gov (United States)

    Silverman, Anne K; Neptune, Richard R

    2014-08-22

    Individuals with unilateral transtibial amputations have greater prevalence of osteoarthritis in the intact knee joint relative to the residual leg and non-amputees, but the cause of this greater prevalence is unclear. The purpose of this study was to compare knee joint contact forces and the muscles contributing to these forces between amputees and non-amputees during walking using forward dynamics simulations. We predicted that the intact knee contact forces would be higher than those of the residual leg and non-amputees. In the axial and mediolateral directions, the intact and non-amputee legs had greater peak tibio-femoral contact forces and impulses relative to the residual leg. The peak axial contact force was greater in the intact leg relative to the non-amputee leg, but the stance phase impulse was greater in the non-amputee leg. The vasti and hamstrings muscles in early stance and gastrocnemius in late stance were the largest contributors to the joint contact forces in the non-amputee and intact legs. Through dynamic coupling, the soleus and gluteus medius also had large contributions, even though they do not span the knee joint. In the residual leg, the prosthesis had large contributions to the joint forces, similar to the soleus in the intact and non-amputee legs. These results identify the muscles that contribute to knee joint contact forces during transtibial amputee walking and suggest that the peak knee contact forces may be more important than the knee contact impulses in explaining the high prevalence of intact leg osteoarthritis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Three cross leg flaps for lower leg reconstruction of Gustilo type III C open fracture

    Directory of Open Access Journals (Sweden)

    Kazufumi Sano

    2016-01-01

    Full Text Available A 60 year old male had Gustilo type III C open fracture of the right lower leg. After radical debridement, the large open defect including certain loss of the bone tissue was successfully augmented and covered, by consecutive three cross-leg flaps, which consisted of the free rectus abdominis musculocutaneous flap, the fibula osteocutaneous flap and the conventional sural flap. Although indication for amputation or preservation is decided with multiple factors in each case, a strategic combination of cross-leg flap, free flap, external fixation and vascular delay could increase the potential of preservation of the lower leg with even disastrous Gustilo type III C.

  19. Single-leg drop landing movement strategies 6 months following first-time acute lateral ankle sprain injury.

    Science.gov (United States)

    Doherty, C; Bleakley, C; Hertel, J; Caulfield, B; Ryan, J; Delahunt, E

    2015-12-01

    No research exists predicating a link between acute ankle sprain injury-affiliated movement patterns and those of chronic ankle instability (CAI) populations. The aim of the current study was to perform a biomechanical analysis of participants, 6 months after they sustained a first-time acute lateral ankle sprain (LAS) injury to establish this link. Fifty-seven participants with a 6-month history of first-time LAS and 20 noninjured participants completed a single-leg drop landing task on both limbs. Three-dimensional kinematic (angular displacement) and sagittal plane kinetic (moment of force) data were acquired for the joints of the lower extremity, from 200 ms pre-initial contact (IC) to 200 ms post-IC. Individual joint stiffnesses and the peak magnitude of the vertical component of the ground reaction force (GRF) were also computed. LAS participants displayed increases in hip flexion and ankle inversion on their injured limb (P < 0.05); this coincided with a reduction in the net flexion-extension moment at the hip joint, with an increase in its stiffness (P < 0.05). There was no difference in the magnitude of the peak vertical GRF for either limb compared with controls. These results demonstrate that altered movement strategies persist in participants, 6 months following acute LAS, which may precipitate the onset of CAI. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Athletes Rated as Poor Single-Leg Squat Performers Display Measureable Differences in Single-Leg Squat Biomechanics Compared to Good Performers.

    Science.gov (United States)

    Garrick, Lachlan E; Alexander, Bryce C; Schache, Anthony G; Pandy, Marcus G; Crossley, Kay M; Collins, Natalie J

    2017-11-15

    It is important to validate single-leg squat visual rating criteria used in clinical practice and research. Foot orthoses may improve single-leg squat performance in those who demonstrate biomechanics associated with increased risk of lower-limb injury. Validate visual rating criteria proposed by Crossley et al, by determining whether athletes rated as poor single-leg squat performers display different single-leg squat biomechanics than good performers; and evaluate immediate effects of foot orthoses on single-leg squat biomechanics in poor performers. Comparative cross-sectional study. University laboratory. 79 asymptomatic athletes underwent video classification of single-leg squat performance based on established visual rating criteria (overall impression, trunk posture, pelvis 'in space', hip movement, knee movement), and were rated as good (n=23), fair (n=41) or poor (n=15) performers. A subset of good (n=16) and poor (n=12) performers underwent biomechanical assessment, completing five continuous single-leg squats on their dominant limb while three-dimensional motion analysis and ground reaction force data were recorded. Poor performers repeated the task standing on prefabricated foot orthoses. Peak external knee adduction moment (KAM) and peak angles for the trunk, hip, knee and ankle. Compared to good performers, poor performers had a significantly lower peak KAM (mean difference 0.11 Nm/kg, 95% confidence interval [CI] 0.02 to 0.2 Nm/kg), higher peak hip adduction angle (-4.3°, -7.6° to -0.9°), and higher peak trunk axial rotation towards their stance limb (3.8°, 0.4° to 7.2°). Foot orthoses significantly increased the peak KAM in poor performers (-0.06 Nm/kg, -0.1 to -0.01 Nm/kg), with values approximating those observed in good performers. Findings validate Crossley et al's visual rating criteria for single-leg squat performance in asymptomatic athletes, and suggest that 'off-the-shelf' foot orthoses may be a simple intervention for poor performers

  1. Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength.

    Science.gov (United States)

    Douma, K W; Regterschot, G R H; Krijnen, W P; Slager, G E C; van der Schans, C P; Zijlstra, W

    2016-01-01

    The ability to generate muscle strength is a pre-requisite for all human movement. Decreased quadriceps muscle strength is frequently observed in older adults and is associated with a decreased performance and activity limitations. To quantify the quadriceps muscle strength and to monitor changes over time, instruments and procedures with a sufficient reliability are needed. The Q Force is an innovative mobile muscle strength measurement instrument suitable to measure in various degrees of extension. Measurements between 110 and 130° extension present the highest values and the most significant increase after training. The objective of this study is to determine the test-retest reliability of muscle strength measurements by the Q Force in older adults in 110° extension. Forty-one healthy older adults, 13 males and 28 females were included in the study. Mean (SD) age was 81.9 (4.89) years. Isometric muscle strength of the Quadriceps muscle was assessed with the Q Force at 110° of knee extension. Participants were measured at two sessions with a three to eight day interval between sessions. To determine relative reliability, the intraclass correlation coefficient (ICC) was calculated. To determine absolute reliability, Bland and Altman Limits of Agreement (LOA) were calculated and t-tests were performed. Relative reliability of the Q Force is good to excellent as all ICC coefficients are higher than 0.75. Generally a large 95 % LOA, reflecting only moderate absolute reliability, is found as exemplified for the peak torque left leg of -18.6 N to 33.8 N and the right leg of -9.2 N to 26.4 N was between 15.7 and 23.6 Newton representing 25.2 % to 39.9 % of the size of the mean. Small systematic differences in mean were found between measurement session 1 and 2. The present study shows that the Q Force has excellent relative test-retest reliability, but limited absolute test-retest reliability. Since the Q Force is relatively cheap and mobile it is suitable for

  2. The acute effects of static stretching on peak force, peak rate of force development and muscle activity during single- and multiple-joint actions in older women.

    Science.gov (United States)

    Gonçalves, Raquel; Gurjão, André Luiz Demantova; Jambassi Filho, José Claudio; Farinatti, Paulo De Tarso Veras; Gobbi, Lilian Teresa Bucken; Gobbi, Sebastião

    2013-01-01

    The present study investigated the acute effects of static stretching on peak force, peak rate of force development and integrated electromyography (iEMG) in 27 older women (65 ± 4 years; 69 ± 9 kg; 157 ± 1 cm; 28 ± 4 kg · m(-2)). The participants were tested during two exercises (leg press and knee extension) after two conditions: stretching and control. The data were collected on four days (counterbalanced with a 24-hour rest period). In the stretching condition, the quadriceps muscle was stretched (knee flexion) for three sets of 30 s with 30 s rest intervals. No significant difference was detected for peak force and peak rate of force development during the single- and multiple-joint exercises, regardless of the following interactions: condition (stretching and control) vs. time (pre x post x 10 x 20 x 30 minutes post; P > 0.05) and exercise vs. time (P > 0.05). Additionally, no significant interaction was found for the iEMG activity (condition vs. time; P > 0.05) in the single- and multiple-joint exercises. In conclusion, a small amount of stretching of an agonist muscle (quadriceps) did not affect the peak force, peak rate of force development and EMG activity in older women during single- and multiple-joint exercises.

  3. BWR operation for life extension

    International Nuclear Information System (INIS)

    Stancavage, P.

    1987-01-01

    Most nuclear power plant life extension studies conducted to date focus on the technology, licensing, and economics of extended service life. The most significant factor in plant longevity, however, is proper operation and maintenance. This paper highlights the benefits of boiling water reactor (BWR) operation for life extension and discusses specific recommendations that will enhance the prospects for safe, reliable, and economic power production in the long term. The benefits of BWR operation for life extension include a lower cost of electric energy production, increased capacity and availability factors, a lower forced outage rate, and reduced occupational exposure to radiation. Operating experience and advanced in technology have provided a wealth of knowledge that can be used to develop specific recommendations for adding years to the expected life of BWR plants. This paper discusses key factors in operation for life extension

  4. Genetic parameters for claw and leg health, foot and leg conformation, and locomotion in Danish Holsteins

    DEFF Research Database (Denmark)

    Laursen, M. V.; Boelling, D.; Mark, Thomas

    2009-01-01

    The purpose of this study was to estimate the genetic correlations among claw and leg health and potential indicator traits. Claw health was defined as absence of heel horn erosion, interdigital dermatitis, interdigital phlegmon, interdigital hyperplasia, laminitis, and sole ulcer. Leg health...

  5. Two-legged hopping in autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Matthew F. Moran

    2013-03-01

    Full Text Available Sensory processing deficits are common within autism spectrum disorders (ASD. Deficits have a heterogeneous dispersion across the spectrum and multimodal processing tasks are thought to magnify integration difficulties. Two-legged hopping in place in sync with an auditory cue (2.3, 3.0 Hz was studied in a group of six individuals with expressive language impaired ASD (ELI-ASD and an age-matched control group. Vertical ground reaction force data were collected and discrete Fourier transforms were utilized to determine dominant hopping cadence. Effective leg stiffness was computed through a mass-spring model representation. The ELI-ASD group were unsuccessful in matching their hopping cadence (2.21±0.30 hops•sec-1, 2.35±0.41 hops•sec-1 to either auditory cue with greater deviations at the 3.0 Hz cue. In contrast, the control group was able to match hopping cadence (2.35±0.06 hops•sec-1, 3.02±0.10 hops•sec-1 to either cue via an adjustment of effective leg stiffness. The ELI-ASD group demonstrated a varied response with an interquartile range (IQR in excess of 0.5 hops•sec-1 as compared to the control group with an IQR < 0.03 hops•sec-1. Several sensorimotor mechanisms could explain the inability of participants with ELI-ASD to modulate motor output to match an external auditory cue. These results suggest that a multimodal gross motor task can (1 discriminate performance among a group of individuals with severe autism, and (2 could be a useful quantitative tool for evaluating motor performance in individuals with ASD individuals.

  6. Leg stiffness can be maintained during reactive hopping despite modified acceleration conditions.

    Science.gov (United States)

    Kramer, A; Ritzmann, R; Gruber, M; Gollhofer, A

    2012-06-26

    The aim of the present study was to evaluate reactive hops under systematically modified acceleration conditions. It was hypothesized that a high preactivity of the leg extensors and phase-specific adjustments of the leg muscle activation would compensate the alterations caused by the various acceleration levels in order to maintain a high leg stiffness, thus enabling the jumper to perform truly reactive jumps with short ground contact times despite the unaccustomed acceleration conditions. Ground reaction forces (GRF), kinematic and electromyographic data of 20 healthy subjects were recorded during reactive hopping in a special sledge jump system for seven different acceleration levels: three acceleration levels with lower than normal gravity (0.7g, 0.8g, 0.9g), one with gravitational acceleration (1g) and three with higher acceleration (1.1g, 1.2g, 1.3g). The increase of the acceleration from 0.7g to 1.3g had no significant effect on the preactivity of the leg extensors, the leg stiffness and the rate of force development. However, it resulted in increased peak GRF (+15%), longer ground contact time (+10%) and increased angular excursion at the ankle and knee joints (+3°). Throughout a wide acceleration range, the subjects were able to maintain a high leg stiffness and perform reactive hops by keeping the preactivity constantly high and adjusting the muscle activity in the later phases. In consequence, it can be concluded that the neuromuscular system can cope with different acceleration levels, at least in the acceleration range used in this study. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Leg and Joint Stiffness in Children with Spastic Diplegic Cerebral Palsy during Level Walking.

    Science.gov (United States)

    Wang, Ting-Ming; Huang, Hsing-Po; Li, Jia-Da; Hong, Shih-Wun; Lo, Wei-Ching; Lu, Tung-Wu

    2015-01-01

    Individual joint deviations are often identified in the analysis of cerebral palsy (CP) gait. However, knowledge is limited as to how these deviations affect the control of the locomotor system as a whole when striving to meet the demands of walking. The current study aimed to bridge the gap by describing the control of the locomotor system in children with diplegic CP in terms of their leg stiffness, both skeletal and muscular components, and associated joint stiffness during gait. Twelve children with spastic diplegia CP and 12 healthy controls walked at a self-selected pace in a gait laboratory while their kinematic and forceplate data were measured and analyzed during loading response, mid-stance, terminal stance and pre-swing. For calculating the leg stiffness, each of the lower limbs was modeled as a non-linear spring, connecting the hip joint center and the corresponding center of pressure, with varying stiffness that was calculated as the slope (gradient) of the axial force vs. the deformation curve. The leg stiffness was further decomposed into skeletal and muscular components considering the alignment of the lower limb. The ankle, knee and hip of the limb were modeled as revolute joints with torsional springs whose stiffness was calculated as the slope of the moment vs. the angle curve of the joint. Independent t-tests were performed for between-group comparisons of all the variables. The CP group significantly decreased the leg stiffness but increased the joint stiffness during stance phase, except during terminal stance where the leg stiffness was increased. They appeared to rely more on muscular contributions to achieve the required leg stiffness, increasing the muscular demands in maintaining the body posture against collapse. Leg stiffness plays a critical role in modulating the kinematics and kinetics of the locomotor system during gait in the diplegic CP.

  8. Leg Length, Body Proportion, and Health: A Review with a Note on Beauty

    Science.gov (United States)

    Bogin, Barry; Varela-Silva, Maria Inês

    2010-01-01

    Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature × 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility. PMID:20617018

  9. Leg and Joint Stiffness in Children with Spastic Diplegic Cerebral Palsy during Level Walking.

    Directory of Open Access Journals (Sweden)

    Ting-Ming Wang

    Full Text Available Individual joint deviations are often identified in the analysis of cerebral palsy (CP gait. However, knowledge is limited as to how these deviations affect the control of the locomotor system as a whole when striving to meet the demands of walking. The current study aimed to bridge the gap by describing the control of the locomotor system in children with diplegic CP in terms of their leg stiffness, both skeletal and muscular components, and associated joint stiffness during gait. Twelve children with spastic diplegia CP and 12 healthy controls walked at a self-selected pace in a gait laboratory while their kinematic and forceplate data were measured and analyzed during loading response, mid-stance, terminal stance and pre-swing. For calculating the leg stiffness, each of the lower limbs was modeled as a non-linear spring, connecting the hip joint center and the corresponding center of pressure, with varying stiffness that was calculated as the slope (gradient of the axial force vs. the deformation curve. The leg stiffness was further decomposed into skeletal and muscular components considering the alignment of the lower limb. The ankle, knee and hip of the limb were modeled as revolute joints with torsional springs whose stiffness was calculated as the slope of the moment vs. the angle curve of the joint. Independent t-tests were performed for between-group comparisons of all the variables. The CP group significantly decreased the leg stiffness but increased the joint stiffness during stance phase, except during terminal stance where the leg stiffness was increased. They appeared to rely more on muscular contributions to achieve the required leg stiffness, increasing the muscular demands in maintaining the body posture against collapse. Leg stiffness plays a critical role in modulating the kinematics and kinetics of the locomotor system during gait in the diplegic CP.

  10. Analysis of risk management practices among extension workers in ...

    African Journals Online (AJOL)

    The extension workers were exposed to hazards / risks such as accident on the farm, car/motor/bicycle accident, injury to the leg/hand, encounter with ... practices among workers in government establishment include: lack of safety training, absence of risk management policy and non-provision of safety gargets. Keywords: ...

  11. Chemical composition of chicken meat produced in extensive indoor ...

    African Journals Online (AJOL)

    Cooled carcasses were dissected into primal cuts. Breast and leg muscle (thigh and drumstick) samples were used for chemical analyses. The obtained results suggested that free range rearing system was more favourable than extensive indoor system, as it resulted in a significantly higher protein content and a lower fat ...

  12. One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise

    DEFF Research Database (Denmark)

    Rud, B; Foss, O; Krustrup, Peter

    2012-01-01

    Aim: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO(2) max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases...... muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. Methods: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO(2) during cycling and one-legged cycling was tested before and after...... training, while VO(2) of the trained leg (TL) and control leg (CL) during cycling was determined after training. Results: VO(2) max for cycling was unaffected by training, although one-legged VO(2) max became 6.7 (2.3)% (mean ± SE) larger with TL than with CL. Also TL citrate synthase activity was higher...

  13. Comparison of the Power Knee and C-Leg during step-up and sit-to-stand tasks.

    Science.gov (United States)

    Wolf, Erik J; Everding, Vanessa Q; Linberg, Alison A; Czerniecki, Joseph M; Gambel, Jeffrey M

    2013-07-01

    For U.S. military service members with transfemoral amputations there are different prosthetic knee systems available that function differently. For example the C-Leg(®) (C-Leg, Otto Bock Healthcare, GmbH, Duderstadt, Germany) is a passive microprocessor knee, and the Power Knee™ (PK, Ossur, Reykjavík, Iceland) provides active positive power generation at the knee joint. This study examined both step-up and sit-to-stand tasks performed by service members using C-Leg and PK systems to determine if the addition of positive power generation to a prosthetic knee can improve symmetry and reduce impact to the remaining joints. For both tasks, average peak sagittal knee powers and vertical ground reaction forces (GRFs) were greater for the intact limb versus the amputated limb across PK and C-Leg groups. For the sit-to-stand task, peak knee power of the amputated limb was greater for PK users versus C-Leg users. Vertical GRFs of the intact limb were greater for the C-Leg versus the PK. The performance of the PK relative to the C-Leg during a STS task illustrated few differences between components and no effect on the intact limb. Published by Elsevier B.V.

  14. The kinematic differences between off-spin and leg-spin bowling in cricket.

    Science.gov (United States)

    Beach, Aaron J; Ferdinands, René E D; Sinclair, Peter J

    2016-09-01

    Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.

  15. High-throughput genotyping of Anopheles mosquitoes using intact legs by Agena Biosciences iPLEX.

    Science.gov (United States)

    Fabrigar, Danica Joy; Hubbart, Christina; Miles, Alistair; Rockett, Kirk

    2016-03-01

    Recent developments in genotyping technologies coupled with the growing desire to characterize genome variation in Anopheles populations open the opportunity to develop more effective genotyping strategies for high-throughput screening. A major bottleneck of this goal is nucleic acid extraction. Here, we examined the feasibility of using intact portions of a mosquito's leg as sources of template DNA for whole-genome amplification (WGA) by primer-extension preamplification. We used the Agena Biosciences MassARRAY(®) platform (formerly Sequenom) to genotype 78 SNPs for 265 WGA leg samples. We performed nucleic acid extraction on 36 mosquito carcasses and compared the genotype call concordance with their corresponding legs and observed full concordance. Using three legs instead of one improved genotyping success rates (96% vs. 89%, respectively), although this difference was not significant. We provide a proof of concept that WGA reactions can be performed directly on mosquito legs, thereby eliminating the need to extract nucleic acid. This approach is straightforward and sensitive and allows both species determination and genotyping of Anopheles mosquitoes to be performed in a high-throughput manner. Our protocol also leaves the mosquito body intact facilitating other experimental analysis to be undertaken on the same sample. Based on our findings, this method would also be suitable for use with other insect species. © 2015 John Wiley & Sons Ltd.

  16. Association between Thigh Muscle Volume and Leg Muscle Power in Older Women.

    Directory of Open Access Journals (Sweden)

    Ulrich Lindemann

    Full Text Available The construct of sarcopenia is still discussed with regard to best appropriate measures of muscle volume and muscle function. The aim of this post-hoc analysis of a cross-sectional experimental study was to investigate and describe the hierarchy of the association between thigh muscle volume and measurements of functional performance in older women. Thigh muscle volume of 68 independently living older women (mean age 77.6 years was measured via magnetic resonance imaging. Isometric strength was assessed for leg extension in a movement laboratory in sitting position with the knee flexed at 90° and for hand grip. Maximum and habitual gait speed was measured on an electronic walk way. Leg muscle power was measured during single leg push and during sit-to-stand performance. Thigh muscle volume was associated with sit-to-stand performance power (r = 0.628, leg push power (r = 0.550, isometric quadriceps strength (r = 0.442, hand grip strength (r = 0.367, fast gait speed (r = 0.291, habitual gait speed (r = 0.256, body mass index (r = 0.411 and age (r = -0.392. Muscle power showed the highest association with thigh muscle volume in healthy older women. Sit-to-stand performance power showed an even higher association with thigh muscle volume compared to single leg push power.

  17. Hop performance and leg muscle power in athletes: Reliability of a test battery.

    Science.gov (United States)

    Kockum, Britta; Heijne, Annette I-L M

    2015-08-01

    To measure the absolute and relative reliability and the smallest real difference (SRD) in three commonly used hop tests, two leg-power tests and the single-leg squat jump. Methodological study. Clinical setting. Fourteen healthy athletes (seven women and seven men) were evaluated in a standardized test-retest design. The Intra-class correlation coefficient (ICC2.1), Standard Error of Measurement (SEM) and SRD were calculated for the vertical jump, one-leg hop for distance, side-hop, single-leg squat jump and knee-flexion and knee-extension power tests. All tests showed good to excellent ICC (0.84-0.98). The SEM (%) ranged between 3.4 and 11.1 for the four hop tests and between 8.1 and 12.4 for the leg-power tests. The SRD (%) for the hop tests ranged between 9.3 and 30.7 and for the three power tests between 22.4 and 34.3. The absolute reliability of this test protocol showed good to excellent ICC values and measurement errors of approximately 10%. This instrument can be recommended for determining function in terms of power in healthy athletes or late in the rehabilitation process. The tests' methodological errors must be considered and caution should be taken regarding the standardization procedure during testing. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Analysis of the body mass index and leg profiles of Asian women after total leg sculpture.

    Science.gov (United States)

    Tsai, Feng-Chou; Chen, Chien-Hao; Lin, Chan-Yi; Ho, Li-Yung

    2009-08-01

    In addition to the conventional methods used to improve leg contours, total leg sculpture, including liposuction, selective neurectomy, and transilluminated powered phlebectomy, provides a one-time solution of leg contour problems, which is a major aesthetic concern among Asian women. The authors present the postoperative results of total leg sculpture and determine any significance and correlation between the leg variables and body mass index by statistical analysis. Thirty female patients who underwent total leg sculpture between 2005 and 2008 were included in the study, and prospective analysis of the patients' data was performed during a follow-up period of 1 year. Local measurement variables and body mass index were recorded, and the correlation between them was determined by Pearson's correlation and regression analysis. A paired t test was used to compare the postoperative outcomes. Subjectively, all patient results were satisfactory. There were significant differences between preoperative and postoperative measurements for all variables for total leg sculpture. Body mass index was strongly correlated with all leg indexes, and there was a significant positive correlation between the index and variables related to the buttocks and upper thigh. The satisfactory postoperative leg variables were buttocks circumference (87.85 cm), thigh circumference (T60, 44.20 cm), maximal calf circumference (32.24 cm), and calf ratio (0.78). Each preoperative body mass index increment represents a 0.3 percent circumference improvement around the buttocks after surgery. No obvious morbidities or long-term hospital stays were noted. Total leg sculpture provides a combined aesthetic solution for improving limb contours with minimal morbidity. Patients with larger body mass index values exhibit better aesthetic improvement than those with smaller values.

  19. Bioinspired legged-robot based on large deformation of flexible skeleton

    International Nuclear Information System (INIS)

    Mayyas, Mohammad

    2014-01-01

    In this article we present STARbot, a bioinspired legged robot capable of multiple locomotion modalities by using large deformation of its skeleton. We construct STARbot by using origami-style folding of flexible laminates. The long-term goal is to provide a robotic platform with maximum mobility on multiple surfaces. This paper particularly studies the quasistatic model of STARbot’s leg under different conditions. We describe the large elastic deformation of a leg under external force, payload, and friction by using a set of non-dimensional, nonlinear approximate equations. We developed a test mechanism that models the motion of a leg in STARbot. We augmented several foot shapes and then tested them on soft to rough grounds. Both simulation and experimental findings were in good agreement. We utilized the model to develop several scales of tri and quad STARbot. We demonstrated the capability of these robots to locomote by combining their leg deformations with their foot motions. The combination provided a design platform for an active suspension STARbot with controlled foot locomotion. This included the ability of STARbot to change size, run over obstacles, walk and slide. Furthermore, in this paper we discuss a cost effective manufacturing and production method for manufacturing STARbot. (paper)

  20. Evaluation of a single leg stance balance test in children.

    Science.gov (United States)

    Zumbrunn, Thomas; MacWilliams, Bruce A; Johnson, Barbara A

    2011-06-01

    Balance is a major determinate of gait. In high functioning individuals without significant vestibular or vision impairments, a ceiling effect may be present when using a double limb support protocol to assess balance function. For these populations, a single leg stance protocol may be more suitable. 47 typically developing (TD) subjects and 10 patients with CEV performed a single leg stance test on a force plate. The center of pressure (COP) was determined and several COP derived variables were calculated. Included measurements were: standard deviation, maximum excursion, area, average radial displacement, path velocity and frequency of the COP. Directional components of suitable variables were used to analyze anterior/posterior and medial/lateral contributions. Correlations with age of TD subjects indicated that all balance variables except frequency were significantly correlated. Most parameters were highly inter-correlated. Age adjusted COP balance variables also correlated to the Bruininks-Oseretsky balance subtest. Highest correlations were determined by the maximum excursion and velocity of the COP in the anterior/posterior direction. Statistical comparisons between the CEV group and a 4-6 TD group indicated significant differences between groups for most COP balance parameters. These results indicated that a single limb balance assessment may be a useful assessment for determining balance impairments in higher functioning children with orthopedic impairments. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Leg muscles activities during hyperventilation following a cycling exercise.

    Science.gov (United States)

    David, P; Mora, I; Terrien, J; Lelard, T; Petitjean, M

    2010-01-01

    The goal of this study was to establish how increased ventilation modifies postural stability, as characterized by body sway and leg muscle activities. Twelve healthy subjects had to perform six 30-second postural tests: one pre-exercise test while breathing gently and then one test every minute for the five minutes immediately following a maximum-intensity, incremental cycling exercise test. Subjects were asked to maintain an upright stance on a force plate for 30 s, with their eyes open. Movement of the centre of pressure in the sagittal plane was monitored in the time and spectral domains. Myoelectric activities of the soleus and tibialis anterior muscles were recorded using surface electromyography. Ventilatory parameters were measured with a portable, telemetric device. Postural changes related to respiratory variations were quantified by coherence analysis. The results showed that hyperventilation induced by exercise was accompanied by a significant increase in postural parameters, indicating a reduction in postural stability following a change in ventilatory drive. Coherence analysis confirmed the ventilatory origin of the postural oscillations. The results suggest that ventilation may be an important factor in postural disturbance during physical activity. The observed increases in leg muscle activities were most likely related to musculo-articular stiffening.

  2. Therapeutic advances in restless legs syndrome (RLS).

    Science.gov (United States)

    Högl, Birgit; Comella, Cynthia

    2015-09-15

    Levodopa and dopamine agonists have been the main treatment for restless legs syndrome during the past decades. Although their efficacy has been well documented over the short term, long-term dopaminergic treatment is often complicated by augmentation, loss of efficacy, and other side effects. Recent large randomized controlled trials provide new evidence for the efficacy of high-potency opioids and α2δ ligands, and several post hoc analyses, meta-analyses, algorithms, and guidelines have been published, often with a specific focus, for example, on augmentation, or on management of restless legs syndrome during pregnancy. Several new contributions to understanding the pathophysiology of restless legs syndrome have been published, but at this time, whether they will have an impact on treatment possibilities in the future cannot be estimated. © 2015 International Parkinson and Movement Disorder Society.

  3. Conjoined legs: Sirenomelia or caudal regression syndrome?

    Directory of Open Access Journals (Sweden)

    Sakti Prasad Das

    2013-01-01

    Full Text Available Presence of single umbilical persistent vitelline artery distinguishes sirenomelia from caudal regression syndrome. We report a case of a12-year-old boy who had bilateral umbilical arteries presented with fusion of both legs in the lower one third of leg. Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting revealed pigeon chest and elevated right shoulder. Posterior examination of the trunk showed thoracic scoliosis with convexity to right. The patient was operated and at 1 year followup the boy had two separate legs with a good aesthetic and functional results.

  4. The extensor tibiae muscle of the stick insect: biomechanical properties of an insect walking leg muscle.

    Science.gov (United States)

    Guschlbauer, Christoph; Scharstein, Hans; Büschges, Ansgar

    2007-03-01

    We investigated the properties of the extensor tibiae muscle of the stick insect (Carausius morosus) middle leg. Muscle geometry of the middle leg was compared to that of the front and hind legs and to the flexor tibiae, respectively. The mean length of the extensor tibiae fibres is 1.41+/-0.23 mm and flexor fibres are 2.11+/-0.30 mm long. The change of fibre length with joint angle was measured and closely follows a cosine function. Its amplitude gives effective moment arm lengths of 0.28+/-0.02 mm for the extensor and 0.56+/-0.04 mm for the flexor. Resting extensor tibiae muscle passive tonic force increased from 2 to 5 mN in the maximum femur-tibia (FT)-joint working range when stretched by ramps. Active muscle properties were measured with simultaneous activation (up to 200 pulses s(-1)) of all three motoneurons innervating the extensor tibiae, because this reflects most closely physiological muscle activation during leg swing. The force-length relationship corresponds closely to the typical characteristic according to the sliding filament hypothesis: it has a plateau at medium fibre lengths, declines nearly linearly in force at both longer and shorter fibre lengths, and the muscle's working range lies in the short to medium fibre length range. Maximum contraction velocity showed a similar relationship. The force-velocity relationship was the traditional Hill curve hyperbola, but deviated from the hyperbolic shape in the region of maximum contraction force close to the isometric contraction. Step-like changes in muscle length induced by loaded release experiments characterised the non-linear series elasticity as a quadratic spring.

  5. Leg Spasticity and Ambulation in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Swathi Balantrapu

    2014-01-01

    Full Text Available Background. Spasticity of the legs is common in multiple sclerosis (MS, but there has been limited research examining its association with ambulatory outcomes. Objective. This study examined spasticity of the legs and its association with multiple measures of ambulation in persons with MS. Methods. The sample included 84 patients with MS. Spasticity of the legs was measured using a 5-point rating scale ranging between 0 (normal and 4 (contracted. Patients completed the 6-minute walk (6 MW, timed 25 foot walk (T25FW, and timed up-and-go (TUG, and O2 cost of walking was measured during the 6 MW. The patients undertook two walking trials on a GAITRite (CIR systems, Inc. for measuring spatial and temporal parameters of gait. The patients completed the Multiple Sclerosis Walking Scale-12 (MSWS-12 and wore an accelerometer over a seven-day period. Results. 52% (n=44 of the sample presented with spasticity of the legs. Those with leg spasticity had significantly worse ambulation as measured by 6 MW (P=0.0001, d=-0.86, T25FW (P=0.003,d=0.72, TUG (P=0.001, d=0.84, MSWS-12 (P=0.0001,d=1.09, O2 cost of walking (P=0.001, d=0.75, average steps/day (P<0.05, d=-0.45, and walking velocity (P<0.05, d=-0.53 and cadence (P<0.05, d=-0.46. Conclusion. Leg spasticity was associated with impairments in ambulation, including alterations in spatiotemporal parameters and free-living walking.

  6. Influence of running velocity on vertical, leg and joint stiffness : modelling and recommendations for future research.

    Science.gov (United States)

    Brughelli, Matt; Cronin, John

    2008-01-01

    Human running can be modelled as either a spring-mass model or multiple springs in series. A force is required to stretch or compress the spring, and thus stiffness, the variable of interest in this paper, can be calculated from the ratio of this force to the change in spring length. Given the link between force and length change, muscle stiffness and mechanical stiffness have been areas of interest to researchers, clinicians, and strength and conditioning practitioners for many years. This review focuses on mechanical stiffness, and in particular, vertical, leg and joint stiffness, since these are the only stiffness types that have been directly calculated during human running. It has been established that as running velocity increases from slow-to-moderate values, leg stiffness remains constant while both vertical stiffness and joint stiffness increase. However, no studies have calculated vertical, leg or joint stiffness over a range of slow-to-moderate values to maximum values in an athletic population. Therefore, the effects of faster running velocities on stiffness are relatively unexplored. Furthermore, no experimental research has examined the effects of training on vertical, leg or joint stiffness and the subsequent effects on running performance. Various methods of training (Olympic style weightlifting, heavy resistance training, plyometrics, eccentric strength training) have shown to be effective at improving running performance. However, the effects of these training methods on vertical, leg and joint stiffness are unknown. As a result, the true importance of stiffness to running performance remains unexplored, and the best practice for changing stiffness to optimize running performance is speculative at best. It is our hope that a better understanding of stiffness, and the influence of running speed on stiffness, will lead to greater interest and an increase in experimental research in this area.

  7. Dynamics of underwater legged locomotion: modeling and experiments on an octopus-inspired robot.

    Science.gov (United States)

    Calisti, M; Corucci, F; Arienti, A; Laschi, C

    2015-07-30

    This paper studies underwater legged locomotion (ULL) by means of a robotic octopus-inspired prototype and its associated model. Two different types of propulsive actions are embedded into the robot model: reaction forces due to leg contact with the ground and hydrodynamic forces such as the drag arising from the sculling motion of the legs. Dynamic parameters of the model are estimated by means of evolutionary techniques and subsequently the model is exploited to highlight some distinctive features of ULL. Specifically, the separation between the center of buoyancy (CoB)/center of mass and density affect the stability and speed of the robot, whereas the sculling movements contribute to propelling the robot even when its legs are detached from the ground. The relevance of these effects is demonstrated through robotic experiments and model simulations; moreover, by slightly changing the position of the CoB in the presence of the same feed-forward activation, a number of different behaviors (i.e. forward and backward locomotion at different speeds) are achieved.

  8. The Molecular Genetics of Restless Legs Syndrome.

    Science.gov (United States)

    Rye, David B

    2015-09-01

    Restless legs syndrome (RLS) is a common sensorimotor trait defined by symptoms that interfere with sleep onset and maintenance in a clinically meaningful way. Nonvolitional myoclonus while awake and asleep is a sign of the disorder and an informative endophenotype. The genetic contributions to RLS/periodic leg movements are substantial, are among the most robust defined to date for a common disease, and account for much of the variance in disease expressivity. The disorder is polygenic, as revealed by recent genome-wide association studies. Experimental studies are revealing mechanistic details of how these common variants might influence RLS expressivity. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Nocturnal leg cramps in older people

    Science.gov (United States)

    Butler, J; Mulkerrin, E; O'Keeffe, S

    2002-01-01

    Nocturnal leg cramps are common in older people. Such cramps are associated with many common diseases and medications. Physiological methods may be useful for preventing cramps in some people, but there have been no controlled trials of these approaches. Quinine is moderately effective in preventing nocturnal leg cramps. However, there are concerns about the risk/benefit ratio with this drug. In patients with severe symptoms, a trial of 4–6 weeks' treatment with quinine is probably still justified, but the efficacy of treatment should be monitored, for example using a sleep and cramp diary. PMID:12415081

  10. Symptom Severity of Restless Legs Syndrome Predicts Its Clinical Course.

    Science.gov (United States)

    Lee, Chung Suk; Kim, Tae; Lee, Sumin; Jeon, Hong Jun; Bang, Young Rong; Yoon, In-Young

    2016-04-01

    This study examines the clinical course of restless legs syndrome according to its severity and factors associated with the remission of restless legs syndrome symptoms. The remission or persistence of restless legs syndrome symptoms was investigated by considering patients with restless legs syndrome at the sleep clinic of Seoul National University Bundang Hospital. All subjects were observed for at least 18 months, and an incidence of remission was defined as having no restless legs syndrome symptoms for at least 1 year. Restless legs syndrome severity was evaluated by the International Restless Legs Syndrome Study Group Rating Scale. A total of 306 patients participated in this study. Over the observation periods of 4.1 ± 1.6 years, the cumulative incidence of remission is 32.5% (95% confidence interval [CI], 27.0-38.0) and decreased with baseline restless legs syndrome severity (P restless legs syndrome cases, respectively. Most cases of remission (82/96) were observed within 1 year, and the remission occurred sooner for mild restless legs syndrome. The hazard ratios of remission by Cox proportional hazards model were lower for moderate (0.556; 95% CI, 0.340-0.909) and severe to very severe (0.193; 95% CI, 0.108-0.343) restless legs syndrome than for mild restless legs syndrome. The remission incidence was lower for those patients who had a family history of restless legs syndrome and were older at restless legs syndrome diagnosis. Mild restless legs syndrome severity, no family history, and young age at restless legs syndrome diagnosis were significant predictors of restless legs syndrome remission. More than 80% of patients with severe restless legs syndrome showed a chronic clinical course. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Review of periodic limb movement and restless leg syndrome

    Directory of Open Access Journals (Sweden)

    Natarajan R

    2010-01-01

    Full Text Available Periodic limb movement (PLM and Restless leg syndrome (RLS are types of sleep disorders that are not very well recognized in clinical practice. While RLS is a clinical diagnosis, the diagnosis of PLM is made by polysomnography. They share the same pathophysiology and often respond to the same treatment. To date all the epidemiological studies have reported the prevalence between 2% and 15%. It has recently become known that mild obstructive sleep apnea and upper airway resistance syndrome (UARS can masquerade as PLM syndrome. New discoveries have been made with regard to genetics and PLM and RLS. Detailed review on this subject should improve the awareness of these disorders, both among general physicians and specialists. Extensive review of journals in the past 20 years was made using Medline search.

  12. THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

    Directory of Open Access Journals (Sweden)

    Nining W. Kusnanik

    2015-05-01

    Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

  13. Clinical characteristics of leg restlessness in Parkinson's disease compared with idiopathic Restless Legs Syndrome.

    Science.gov (United States)

    Zhu, Xiao-Ying; Liu, Ye; Zhang, Xiao-Jin; Yang, Wen-Hao; Feng, Ya; Ondo, William G; Tan, Eng-King; Wu, Yun-Cheng

    2015-10-15

    There is limited data on motor restlessness in Parkinson's disease (PD). Here we evaluate for clinical differences between cohorts of idiopathic Restless Legs Syndrome (iRLS), PD patients with leg restlessness, and PD with RLS. We examined 276 consecutive PD patients for leg restlessness symptoms, we compared clinical features of PD patients with RLS, PD patients with leg restlessness but not meeting RLS criteria, PD patient without RLS and iRLS. A total of 262 PD patients who satisfied the inclusion criteria were analyzed. After excluding 23 possible secondary RLS or mimics, 28 were diagnosed with RLS and 18 with leg motor restlessness (LMR). Compared with iRLS patients, PD patients with RLS or LMR had older age of RLS/LMR onset, shorter duration of leg restlessness, less positive family history, different seasonal trends and more unilaterality of leg restlessness symptom (Pleg restlessness. PD with LMR had less severe Parkinsonism (Pleg restlessness (P<0.01) symptoms than PD with RLS. Clinical characteristics of PD patients with RLS and LMR were different from iRLS, differentiating these various subtypes can facilitate optimal treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Task driven optimal leg trajectories in insect-scale legged microrobots

    Science.gov (United States)

    Doshi, Neel; Goldberg, Benjamin; Jayaram, Kaushik; Wood, Robert

    Origami inspired layered manufacturing techniques and 3D-printing have enabled the development of highly articulated legged robots at the insect-scale, including the 1.43g Harvard Ambulatory MicroRobot (HAMR). Research on these platforms has expanded its focus from manufacturing aspects to include design optimization and control for application-driven tasks. Consequently, the choice of gait selection, body morphology, leg trajectory, foot design, etc. have become areas of active research. HAMR has two controlled degrees-of-freedom per leg, making it an ideal candidate for exploring leg trajectory. We will discuss our work towards optimizing HAMR's leg trajectories for two different tasks: climbing using electroadhesives and level ground running (5-10 BL/s). These tasks demonstrate the ability of single platform to adapt to vastly different locomotive scenarios: quasi-static climbing with controlled ground contact, and dynamic running with un-controlled ground contact. We will utilize trajectory optimization methods informed by existing models and experimental studies to determine leg trajectories for each task. We also plan to discuss how task specifications and choice of objective function have contributed to the shape of these optimal leg trajectories.

  15. Impaired voluntary quadriceps force control following anterior cruciate ligament reconstruction: relationship with knee function.

    Science.gov (United States)

    Perraton, Luke; Clark, Ross; Crossley, Kay; Pua, Yong-Hao; Whitehead, Tim; Morris, Hayden; Telianidis, Stacey; Bryant, Adam

    2017-05-01

    Impairments in quadriceps force control and altered quadriceps and hamstring muscle activation strategies have been observed following anterior cruciate ligament reconstruction; however, the functional implications of these impairments are unclear. This study examined the cross-sectional associations between quadriceps force control, quadriceps activation, hamstring coactivation and clinically assessed knee function following anterior cruciate ligament reconstruction with a hamstring graft. Sixty-six patients (18 ± 3 months following surgery) and 41 uninjured individuals participated. Quadriceps force control was assessed using an isometric knee extension task. Participants cyclically increased and decreased quadriceps force at slow speeds between 5 and 30 % maximum voluntary isometric contraction matching a moving target displayed on a screen. Quadriceps activation and hamstring coactivation were assessed concurrently using surface electromyography. Knee function was assessed with the Cincinnati Knee Rating Scale and three single-leg hop tests. The reconstructed group completed the task with 48 % greater root-mean-square error (RMSE), indicating significantly worse quadriceps force control (p anterior cruciate ligament reconstruction and may contribute to irregular knee joint loading and the onset or progression of knee osteoarthritis. Impairments in quadriceps force control and altered muscle activation strategies may be modifiable through neuromuscular training, and this is an area for future research. Case-control study, Level III.

  16. The Reactive Leg Drop: a Simple and Novel Sensory-Motor Assessment to Predict Fall Risk in Older Individuals.

    Science.gov (United States)

    Magrini, Mitchel A; Thiele, Ryan M; Colquhoun, Ryan J; Barrera Curiel, Alejandra; Blackstock, Taryn S; DeFreitas, Jason M

    2018-01-10

    There is need for a functional ability test that appropriately assesses the rapid integration of the sensory and motor systems required for older adults to recover from a slip. The purpose of this study was to assess the efficacy and reliability of a novel test, the reactive leg drop, for assessing sensory-motor function in older adults. Fourteen young (YW; mean age = 20yrs) and 11 older women (OW; mean age = 76yrs) participated in this study. For each drop, the leg was passively moved to full extension and then released. The subjects had to recognize their leg was free-falling and reactively kick up as quickly as possible during varying sensory conditions. To assess the leg drop's reliance on proprioception, other proprioceptive tests (e.g. patellar tendon reflexes and balance) were separately performed. Leg drops performed with the eyes closed (p=0.011) and with a blocked view of their leg (p=0.033) showed significant differences in drop angle between the YW and OW. Significant relationships between leg drop conditions and balance were observed in the OW that were not present within YW. When collapsed across groups, reflex latency was correlated with drop angle when the eyes were closed. The reactive leg drop was age sensitive, reliable, and likely reliant on proprioception, as shown by relationships to other sensory-motor assessments, such as balance and the patellar reflex. Although more research is needed, we propose that the reactive leg drop is an effective tool to assess sensory-motor integration in a manner that may mimic fall recovery.

  17. Radioprotection by WR-151327 against the late normal tissue damage in mouse hind legs from gamma ray radiation

    International Nuclear Information System (INIS)

    Matsushita, Satoru; Ando, Koichi; Koike, Sachiko

    1994-01-01

    To evaluate the protective effect of WR-151327 on late radiation-induced damaged to normal tissues in mice, the right hind legs of mice with or without WR-151327 administration (400 mg/kg) were irradiated with 137 Cs gamma rays. Leg contracture and skin shrinkage assays were performed at 380 days after irradiation. The mice were killed on day 400 postirradiation and histological sections of the legs were made. The thickness of the dermis, epidermis, and skin (dermis plus epidermis) was measured. The muscular area of the legs and the posterior knee angle between the femur and tibia were also measured. The left hind legs were similarly assessed as nonirradiated controls. Group means and standard deviations were calculated and dose-response curves were drawn for every endpoint. Then, the dose modifying factor (DMF) for each endpoint and the correlations among endpoints were determined. Latae damage assayed by leg contracture and skin shrinkage progressed with increasing radiation dose. However, it was reduced by drug treatment. The significant effect was indicated for skin shrinkage by a DMF of 1.8 at 35%. The DMF for leg contracture was 1.3 at 6 mm. In the irradiated legs, epidermal hyperplasia and dermal fibrosis in the skin, muscular atrophy, and extension disturbance of the knee joint were observed. These changes progressed with increasing radiation dose. Skin damage assayed by the present endpoints was also reduced by drug treatment by DMFs of 1.4 to 1.7. However, DMFs for damage to the muscle and knee were not determined because no isoeffect was observed. There were good correlations between leg contracture or skin shrinkage and the other endpoints in both untreated and drug-treated mice. WR-151327 has the potential to protect against radiation-induced late normal tissue damage. 17 refs., 6 figs., 2 tabs

  18. Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg and Mauch SNS prosthetic knees.

    Science.gov (United States)

    Segal, Ava D; Orendurff, Michael S; Klute, Glenn K; McDowell, Martin L; Pecoraro, Janice A; Shofer, Jane; Czerniecki, Joseph M

    2006-01-01

    The C-Leg (Otto Bock, Duderstadt, Germany) is a microprocessor-controlled prosthetic knee that may enhance amputee gait. This intrasubject randomized study compared the gait biomechanics of transfemoral amputees wearing the C-Leg with those wearing a common noncomputerized prosthesis, the Mauch SNS (Ossur, Reykjavik, Iceland). After subjects had a 3-month acclimation period with each prosthetic knee, typical gait biomechanical data were collected in a gait laboratory. At a controlled walking speed (CWS), peak swing phase knee-flexion angle decreased for the C-Leg group compared with the Mauch SNS group (55.2 degrees +/- 6.5 degrees vs 64.41 degrees +/- 5.8 degrees , respectively; p = 0.005); the C-Leg group was similar to control subjects' peak swing knee-flexion angle (56.0 degrees +/- 3.4 degrees ). Stance knee-flexion moment increased for the C-Leg group compared with the Mauch SNS group (0.142 +/- 0.05 vs 0.067 +/- 0.07 N"m, respectively; p = 0.01), but remained significantly reduced compared with control subjects (0.477 +/- 0.1 N"m). Prosthetic limb step length at CWS was less for the C-Leg group compared with the Mauch SNS group (0.66 +/- 0.04 vs 0.70 +/- 0.06 m, respectively; p = 0.005), which resulted in increased symmetry between limbs for the C-Leg group. Subjects also walked faster with the C-Leg versus the Mauch SNS (1.30 +/- 0.1 vs 1.21 +/- 0.1 m/s, respectively; p = 0.004). The C-Leg prosthetic limb vertical ground reaction force decreased compared with the Mauch SNS (96.3 +/- 4.7 vs 100.3 +/- 7.5 % body weight, respectively; p = 0.0092).

  19. Elegant Shadow Making Tiny Force Visible for Water-Walking Arthropods and Updated Archimedes' Principle.

    Science.gov (United States)

    Zheng, Yelong; Lu, Hongyu; Yin, Wei; Tao, Dashuai; Shi, Lichun; Tian, Yu

    2016-10-07

    Forces acted on legs of water-walking arthropods with weights in dynes are of great interest for entomologist, physicists, and engineers. While their floating mechanism has been recognized, the in vivo leg forces stationary have not yet been simultaneously achieved. In this study, their elegant bright-edged leg shadows are used to make the tiny forces visible and measurable based on the updated Archimedes' principle. The force was approximately proportional to the shadow area with a resolution from nanonewton to piconewton/pixel. The sum of leg forces agreed well with the body weight measured with an accurate electronic balance, which verified updated Archimedes' principle at the arthropod level. The slight changes of vertical body weight focus position and the body pitch angle have also been revealed for the first time. The visualization of tiny force by shadow is cost-effective and very sensitive and could be used in many other applications.

  20. Analysis of Foot Slippage Effects on an Actuated Spring-Mass Model of Dynamic Legged Locomotion

    Directory of Open Access Journals (Sweden)

    Yizhar Or

    2016-04-01

    Full Text Available The classical model of spring-loaded inverted pendulum (SLIP and its extensions have been widely accepted as a simple description of dynamic legged locomotion at various scales in humans, legged robots and animals. Similar to the majority of models in the literature, the SLIP model assumes ideal sticking contact of the foot. However, there are practical scenarios of low ground friction that causes foot slippage, which can have a significant influence on dynamic behaviour. In this work, an extension of the SLIP model with two masses and torque actuation is considered, which accounts for possible slippage under Coulomb's friction law. The hybrid dynamics of this model is formulated and numerical simulations under representative parameter values reveal several types of stable periodic solutions with stick-slip transitions. Remarkably, it is found that slippage due to low friction can sometimes increase average speed and improve energetic efficiency by significantly reducing the mechanical cost of transport.

  1. [The influence of the leg load and the support mobility under leg on the anticipatory postural adjustment].

    Science.gov (United States)

    Kazennikov, O V; Kireeva, T B; Shlykov, V Iu

    2015-01-01

    Anticipatory postural adjustment is an essential part of equilibrium maintainance during standing in human. So changes in stance condition could affect both control of equilibrium and anticipatory adjustment. Anticipatory changes in the stabilogram of each leg were studied in standing subject during the early stage of quick right arm lifting while legs were on two separated supports. The center of pressure (CP) movement was analyzed in three variants of experiment: both legs on immovable support, with only right leg on the movable support and with only left leg on the moveable support. In each standing condition subject stood with symmetrical load on two legs or with the load voluntary transferred to one leg. The anticipatory CP shift depended on the mobility of the support under the leg and on loading of the leg. While standing on unmovable supports with symmetrical load on the legs before lifting of the right arm CP of right leg shifted backward and CP of left leg--forward. While standing with one leg on movable support the anticipatory CP shift of this leg was small and did not depend on the load on the leg. However the shift of CP of the leg that was placed on the unmovable support depended on the load in the same way as in the case when both legs were on unmovable supports. Results suggested that since on movable support the support and proprioceptive afferent flow from distal part of the leg that was did not supply unambiguous information about body position, the role of distal joints in posture control is reduced.

  2. ForcePAD

    DEFF Research Database (Denmark)

    Lindemann, J.; Damkilde, Lars

    2009-01-01

    ForcePAD is a 2-dimensional finite element application that started as a concept application for finite element modeling. Over the course of 10 years the application has been evolved into an application that is used extensively in both an educational setting as well as a tool for design and engin......ForcePAD is a 2-dimensional finite element application that started as a concept application for finite element modeling. Over the course of 10 years the application has been evolved into an application that is used extensively in both an educational setting as well as a tool for design...

  3. An automatic hinge system for leg orthoses

    NARCIS (Netherlands)

    Rietman, J. S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J. P. K.; Geertzen, J. H. B.

    2004-01-01

    This paper describes a new automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients, fitted

  4. An automatic hinge system for leg orthoses

    NARCIS (Netherlands)

    Rietman, J.S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J.P.K.; Geertzen, J.H.B.

    This paper describes a new, automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients,

  5. Chronic leg ulcer caused by Mycobacterium immunogenum

    NARCIS (Netherlands)

    Loots, Miriam A. M.; de Jong, Menno D.; van Soolingen, Dick; Wetsteyn, José C. F. M.; Faber, William R.

    2005-01-01

    Rare tropical skin diseases are seen more frequently in Western countries because of the increased popularity of visiting tropical regions. A 55-year-old white man developed a painless leg ulcer after traveling in Guatemala and Belize. A mycobacterium was cultured from a biopsy specimen and was

  6. X-Ray Exam: Femur (Upper Leg)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Femur (Upper Leg) KidsHealth / For Parents / X- ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  7. The restless legs syndrome (Ekbom's syndrome)

    African Journals Online (AJOL)

    1983-04-30

    Apr 30, 1983 ... same distribution as the paraesthesiae; and (v) anxiety, tension or mild depression. Paraesthesiae or creeping sensations are usually confined to the calves. They are extremely unpleasant and deep-seated in muscles or bones rather than in the skin, mostly affecting the legs between the knee and ankle.

  8. Leg og læring

    DEFF Research Database (Denmark)

    Pedersen, Annette

    2008-01-01

    Leg synes at have et potentiale som metode til at fremme læring. Men hvordan? Legen har en vis grad af parallelitet med den virkelige verden i dens interaktive og relationelle strukturer. Det bliver muligt at finde nye meninger i interaktioner, som refererer til vante interaktionsformer, men...

  9. Functional scoliosis caused by leg length discrepancy

    Science.gov (United States)

    Daniszewska, Barbara; Zolynski, Krystian

    2010-01-01

    Introduction Leg length discrepancy (LLD) causes pelvic obliquity in the frontal plane and lumbar scoliosis with convexity towards the shorter extremity. Leg length discrepancy is observed in 3-15% of the population. Unequalized lower limb length discrepancy leads to posture deformation, gait asymmetry, low back pain and discopathy. Material and methods In the years 1998-2006, 369 children, aged 5 to 17 years (209 girls, 160 boys) with LLD-related functional scoliosis were treated. An external or internal shoe lift was applied. Results Among 369 children the discrepancy of 0.5 cm was observed in 27, 1 cm in 329, 1.5 cm in 9 and 2 cm in 4 children. During the first follow-up examination, within 2 weeks, the adjustment of the spine to new static conditions was noted and correction of the curve in 316 examined children (83.7%). In 53 children (14.7%) the correction was observed later and was accompanied by slight low back pain. The time needed for real equalization of limbs was 3 to 24 months. The time needed for real equalization of the discrepancy was 11.3 months. Conclusions Leg length discrepancy equalization results in elimination of scoliosis. Leg length discrepancy < 2 cm is a static disorder; that is why measurements should be performed in a standing position using blocks of adequate thickness and the position of the posterior superior iliac spine should be estimated. PMID:22371777

  10. Omnidirectional Wheel-Legged Hybrid Mobile Robot

    Directory of Open Access Journals (Sweden)

    István Vilikó

    2015-06-01

    Full Text Available The purpose of developing hybrid locomotion systems is to merge the advantages and to eliminate the disadvantages of different type of locomotion. The proposed solution combines wheeled and legged locomotion methods. This paper presents the mechatronic design approach and the development stages of the prototype.

  11. Parallel kinematics robot with five legs

    NARCIS (Netherlands)

    Lambert, P.

    2011-01-01

    Robot with multiple degrees of freedom comprising five legs (2) linked at a first of their ends to a base ( 3), and at a second of their ends opposite to the first ends to a mobile platform (4), which platform carries at least one tool (5, 6, 121, 12 "), and wherein the robot further comprises an

  12. Sociologists in Extension

    Science.gov (United States)

    Christenson, James A.; And Others

    1977-01-01

    The article describes the work activities of the extension sociologist, the relative advantage and disadvantage of extension roles in relation to teaching/research roles, and the relevance of sociological training and research for extension work. (NQ)

  13. Blast Performance of Commercially Available Demining Footwear: A Summary of Experimental Trials on Surrogate Legs

    Science.gov (United States)

    2008-10-01

    of definitions NAVICULAR SECOND CUNEIFORM FIRST CUNEIFORM PHALANGES The lower limb (left) and the foot/ankle complex anatomy [ Tortora . 1984. 2003...talus, which is the only bone to articulate with the tibia and the fibula, transmits all the forces from the foot to the leg. References Tortora , G...Anagnostakos. N. (1984), Principles of Anatomy and Physiology, Fourth Edition, Harper & Row, Publishers, Inc.. New York, NY. Tortora G.J. and

  14. Effect of Running Speed and Leg Prostheses on Mediolateral Foot Placement and Its Variability

    Science.gov (United States)

    Arellano, Christopher J.; McDermott, William J.; Kram, Rodger; Grabowski, Alena M.

    2015-01-01

    This study examined the effects of speed and leg prostheses on mediolateral (ML) foot placement and its variability in sprinters with and without transtibial amputations. We hypothesized that ML foot placement variability would: 1. increase with running speed up to maximum speed and 2. be symmetrical between the legs of non-amputee sprinters but asymmetrically greater for the affected leg of sprinters with a unilateral transtibial amputation. We measured the midline of the body (kinematic data) and center of pressure (kinetic data) in the ML direction while 12 non-amputee sprinters and 7 Paralympic sprinters with transtibial amputations (6 unilateral, 1 bilateral) ran across a range of speeds up to maximum speed on a high-speed force measuring treadmill. We quantified ML foot placement relative to the body’s midline and its variability. We interpret our results with respect to a hypothesized relation between ML foot placement variability and lateral balance. We infer that greater ML foot placement variability indicates greater challenges with maintaining lateral balance. In non-amputee sprinters, ML foot placement variability for each leg increased substantially and symmetrically across speed. In sprinters with a unilateral amputation, ML foot placement variability for the affected and unaffected leg also increased substantially, but was asymmetric across speeds. In general, ML foot placement variability for sprinters with a unilateral amputation was within the range observed in non-amputee sprinters. For the sprinter with bilateral amputations, both affected legs exhibited the greatest increase in ML foot placement variability with speed. Overall, we find that maintaining lateral balance becomes increasingly challenging at faster speeds up to maximum speed but was equally challenging for sprinters with and without a unilateral transtibial amputation. Finally, when compared to all other sprinters in our subject pool, maintaining lateral balance appears to be the

  15. Effect of running speed and leg prostheses on mediolateral foot placement and its variability.

    Directory of Open Access Journals (Sweden)

    Christopher J Arellano

    Full Text Available This study examined the effects of speed and leg prostheses on mediolateral (ML foot placement and its variability in sprinters with and without transtibial amputations. We hypothesized that ML foot placement variability would: 1. increase with running speed up to maximum speed and 2. be symmetrical between the legs of non-amputee sprinters but asymmetrically greater for the affected leg of sprinters with a unilateral transtibial amputation. We measured the midline of the body (kinematic data and center of pressure (kinetic data in the ML direction while 12 non-amputee sprinters and 7 Paralympic sprinters with transtibial amputations (6 unilateral, 1 bilateral ran across a range of speeds up to maximum speed on a high-speed force measuring treadmill. We quantified ML foot placement relative to the body's midline and its variability. We interpret our results with respect to a hypothesized relation between ML foot placement variability and lateral balance. We infer that greater ML foot placement variability indicates greater challenges with maintaining lateral balance. In non-amputee sprinters, ML foot placement variability for each leg increased substantially and symmetrically across speed. In sprinters with a unilateral amputation, ML foot placement variability for the affected and unaffected leg also increased substantially, but was asymmetric across speeds. In general, ML foot placement variability for sprinters with a unilateral amputation was within the range observed in non-amputee sprinters. For the sprinter with bilateral amputations, both affected legs exhibited the greatest increase in ML foot placement variability with speed. Overall, we find that maintaining lateral balance becomes increasingly challenging at faster speeds up to maximum speed but was equally challenging for sprinters with and without a unilateral transtibial amputation. Finally, when compared to all other sprinters in our subject pool, maintaining lateral balance

  16. Interventions for leg cramps in pregnancy.

    Science.gov (United States)

    Zhou, Kunyan; West, Helen M; Zhang, Jing; Xu, Liangzhi; Li, Wenjuan

    2015-08-11

    Leg cramps are a common problem in pregnancy. Various interventions have been used to treat them, including drug, electrolyte and vitamin therapies, and non-drug therapies. To assess the effectiveness and safety of different interventions for treating leg cramps in pregnancy. We searched the Cochrane Pregnancy and Childbirth Group's Register (31 March 2015) and reference lists of retrieved studies. Randomised controlled trials (RCTs) of any intervention (drug, electrolyte, vitamin or non-drug therapies) for treatment of leg cramps in pregnancy compared with placebo, no treatment or other treatment. Quinine was excluded for its known adverse effects (teratogenicity). Cluster-RCTS were considered for inclusion. Quasi-RCTs and cross-over studies were excluded. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We included six studies (390 women). Four trials compared oral magnesium with placebo/no treatment, two compared oral calcium with no treatment, one compared oral vitamin B versus no treatment, and one compared oral calcium with oral vitamin C. Two of the trials were well-conducted and reported, the other four had design limitations. The process of random allocation was sub-optimal in three studies, and blinding was not attempted in two. Outcomes were reported in different ways, precluding the use of meta-analysis and limiting the strength of our conclusions.The 'no treatment' group in one four-arm trial has been used as the comparison group for the composite outcome (intensity and frequency of leg cramps) in magnesium, calcium, and vitamin B versus no treatment. This gives it disproportionate weight in the overall analysis, thus interpretation of these results should be cautious. Oral magnesium versus placebo/no treatmentMagnesium (taken orally for two to four weeks) did not consistently reduce the frequency of leg cramps compared with placebo or no treatment. Outcomes that showed

  17. An eight-legged tactile sensor to estimate coefficient of static friction.

    Science.gov (United States)

    Wei Chen; Rodpongpun, Sura; Luo, William; Isaacson, Nathan; Kark, Lauren; Khamis, Heba; Redmond, Stephen J

    2015-08-01

    It is well known that a tangential force larger than the maximum static friction force is required to initiate the sliding motion between two objects, which is governed by a material constant called the coefficient of static friction. Therefore, knowing the coefficient of static friction is of great importance for robot grippers which wish to maintain a stable and precise grip on an object during various manipulation tasks. Importantly, it is most useful if grippers can estimate the coefficient of static friction without having to explicitly explore the object first, such as lifting the object and reducing the grip force until it slips. A novel eight-legged sensor, based on simplified theoretical principles of friction is presented here to estimate the coefficient of static friction between a planar surface and the prototype sensor. Each of the sensor's eight legs are straight and rigid, and oriented at a specified angle with respect to the vertical, allowing it to estimate one of five ranges (5 = 8/2 + 1) that the coefficient of static friction can occupy. The coefficient of friction can be estimated by determining whether the legs have slipped or not when pressed against a surface. The coefficients of static friction between the sensor and five different materials were estimated and compared to a measurement from traditional methods. A least-squares linear fit of the sensor estimated coefficient showed good correlation with the reference coefficient with a gradient close to one and an r(2) value greater than 0.9.

  18. Leg power among malaysian netball players | Geok | African Journal ...

    African Journals Online (AJOL)

    The purpose of the study was to compare the leg power among Malaysian national netball players according to their age and playing position. The Vertical Jump Test was chosen to measure the leg power by using “Digital Indication Jump Meter” device. The results of the Vertical Jump Test were used to compare the leg ...

  19. Protection against high intravascular pressure in giraffe legs

    DEFF Research Database (Denmark)

    Petersen, Karin K; Hørlyck, Arne; Østergaard, Kristine Hovkjær

    2013-01-01

    The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination...

  20. Protection by S-2-(3-aminopropylamino)ethylphosphorothioic acid against radiation-induced leg contractures in mice

    International Nuclear Information System (INIS)

    Hunter, N.; Milas, L.

    1983-01-01

    S-2-(3-Aminopropylamino)ethylphosphorothioic acid (WR-2721) was shown to provide marked protection against development of radiation-induced leg contractures in C3Hf/Kam mice whose legs were exposed to single doses of gamma-radiation. The radiation doses ranged from 3300 to 6200 rads delivered to the right hind thighs from two parallelly opposed 137Cs sources. WR-2721 was given i.p. 30 min before irradiation. The severity of radiation-induced leg contractures in untreated and WR-2721-treated mice was followed for 342 days after irradiation. The degree of leg contractures in both control and WR-2721-treated mice increased up to 100 days after radiation, when the change stabilized, remaining more or less at the same level to the end of the observation period. During this entire period, the severity of contractures was less in WR-2721-treated mice. The dose-modifying factor for the level of 5 mm reduction in leg extension was 1.5 at 182 days after irradiation. Since WR-2721 did not prevent the radiocurability of 8-mm fibrosarcomas growing in the same legs, these data imply that WR-2721 has a high potential for increasing therapeutic gain when combined with irradiation in the treatment of tumors of an appreciable size

  1. Immediate effects of the trunk stabilizing exercise on static balance parameters in double-leg and one-leg stances

    OpenAIRE

    Kim, Jwa-jun; Park, Se-yeon

    2016-01-01

    [Purpose] The purpose of this study was to evaluate the immediate effect of stabilizing exercise using the PNF technique on standing balance in one-leg and double-leg stances. [Subjects and Methods] The present study recruited 34 healthy participants from a local university. The Participants performed four balance tests (double-leg stance with and without vision, one-leg stance with and without vision), before and after exercise. The exercise consisted of exercises performed using PNF techniq...

  2. Correlation between Changes in Leg Blood Flow and Ankle-Brachial Pressure Index: A Study Using Laser Doppler Flowmeter -The 1st Report-.

    Science.gov (United States)

    Suzuki, Kazuyoshi; Sekiguchi, Miho; Midorikawa, Hirofumi; Sato, Koichi; Akase, Kazuyoshi; Sawada, Renshi; Konno, Shin-Ichi

    2011-01-01

    The objective of this study was to use non-invasive laser Doppler flowmeter to measure changes in blood flow in peripheral vessels in the legs before and after stress induced by leg elevation stress test and investigate correlations with the ankle-brachial pressure index (ABI). Subjects included 28 patients over 20 years of age (mean, 73 years) who reported chiefly of leg symptoms such as intermittent claudication, numbness, chills, or cramps had been examined at the study institution, and agreed to participate in the study. The ABI of both legs was measured, and patients were divided into two groups: low ABI (ABI ≤0.9) and normal ABI (ABI ≥0.9). Blood flow in the big toe was measured using a box-type laser Doppler flowmeter before, during, and after leg-elevation stress. Amplitude of the recorded waveform and changes in blood flow were compared. Average ABI was 1.09 ± 0.10 in the normal ABI group (33 legs) and 0.68 ± 0.17 in the low ABI group (21 legs). Amplitude before and during stress was significantly smaller in the low ABI group than in the normal ABI group (p leg extension and elevation stress, there was a correlation between change in blood flow and amplitude, and ABI during stress. A box-type laser Doppler flowmeter may provide a means of screening for peripheral arterial disease.

  3. Unraveling protein-protein interactions in clathrin assemblies via atomic force spectroscopy.

    Science.gov (United States)

    Jin, Albert J; Lafer, Eileen M; Peng, Jennifer Q; Smith, Paul D; Nossal, Ralph

    2013-03-01

    Atomic force microscopy (AFM), single molecule force spectroscopy (SMFS), and single particle force spectroscopy (SPFS) are used to characterize intermolecular interactions and domain structures of clathrin triskelia and clathrin-coated vesicles (CCVs). The latter are involved in receptor-mediated endocytosis (RME) and other trafficking pathways. Here, we subject individual triskelia, bovine-brain CCVs, and reconstituted clathrin-AP180 coats to AFM-SMFS and AFM-SPFS pulling experiments and apply novel analytics to extract force-extension relations from very large data sets. The spectroscopic fingerprints of these samples differ markedly, providing important new information about the mechanism of CCV uncoating. For individual triskelia, SMFS reveals a series of events associated with heavy chain alpha-helix hairpin unfolding, as well as cooperative unraveling of several hairpin domains. SPFS of clathrin assemblies exposes weaker clathrin-clathrin interactions that are indicative of inter-leg association essential for RME and intracellular trafficking. Clathrin-AP180 coats are energetically easier to unravel than the coats of CCVs, with a non-trivial dependence on force-loading rate. Published by Elsevier Inc.

  4. Clinical quality indicators of venous leg ulcers

    DEFF Research Database (Denmark)

    Kjaer, Monica L; Mainz, Jan; Soernsen, Lars T

    2005-01-01

    and reliable evidence-based quality indicators of venous leg ulcer care. A Scandinavian multidisciplinary, cross-sectional panel of wound healing experts developed clinical quality indicators on the basis of scientific evidence from the literature and subsequent group nominal consensus of the panel......; an independent medical doctor tested the feasibility and reliability of these clinical indicators, assessing the quality of medical technical care on 100 consecutive venous leg ulcer patients. Main outcome measures were healing, recurrence, pain, venous disease diagnosis, differential diagnosis and treatment......%) were assessed for venous surgery. Distal arterial pressure was measured following initial examination in 33 of the patients (34%). All patients (100%) were prescribed compression therapy. Of the 98 patients, 11 (11%) had ulcers recur in 3 months and 72 (73%) healed in 12 months, which is in line...

  5. Effects of Prophylactic Knee Bracing on Lower Limb Kinematics, Kinetics, and Energetics During Double-Leg Drop Landing at 2 Heights.

    Science.gov (United States)

    Ewing, Katie A; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

    2016-07-01

    Anterior cruciate ligament (ACL) injuries commonly occur during landing maneuvers. Prophylactic knee braces were introduced to reduce the risk of ACL injuries, but their effectiveness is debated. We hypothesized that bracing would improve biomechanical factors previously related to the risk of ACL injuries, such as increased hip and knee flexion angles at initial contact and at peak vertical ground-reaction force (GRF), increased ankle plantar flexion angles at initial contact, decreased peak GRFs, and decreased peak knee extension moment. We also hypothesized that bracing would increase the negative power and work of the hip joint and would decrease the negative power and work of the knee and ankle joints. Controlled laboratory study. Three-dimensional motion and force plate data were collected from 8 female and 7 male recreational athletes performing double-leg drop landings from 0.30 m and 0.60 m with and without a prophylactic knee brace. GRFs, joint angles, moments, power, and work were calculated for each athlete with and without a knee brace. Prophylactic knee bracing increased the hip flexion angle at peak GRF by 5.56° (P knee flexion angle at peak GRF by 4.75° (P = .001), and peak hip extension moment by 0.44 N·m/kg (P knee and ankle. No differences in peak GRFs and peak knee extension moment were observed with bracing. The application of a prophylactic knee brace resulted in improvements in important biomechanical factors associated with the risk of ACL injuries. Prophylactic knee braces may help reduce the risk of noncontact knee injuries in recreational and professional athletes while playing sports. Further studies should investigate different types of prophylactic knee braces in conjunction with existing training interventions so that the sports medicine community can better assess the effectiveness of prophylactic knee bracing. © 2016 The Author(s).

  6. Explosive resistance training increases rate of force development in ankle dorsiflexors and gait function in adults with cerebral palsy

    DEFF Research Database (Denmark)

    Kirk, Henrik; Geertsen, Svend Sparre; Lorentzen, Jakob

    2016-01-01

    dorsiflexion, plantarflexion, leg press, hamstring curls, abdominal curls and back extension 3 days/week for 12 weeks, with 3 sets per exercise and progressing during the training period from 12-6 RM. RFDdf, 3-D gait analysis, functional performance and ankle joint passive- and reflex-mediated muscle stiffness......Alterations in passive elastic properties of muscles and reduced ability to quickly generate muscle force contribute to impaired gait function in adults with cerebral palsy (CP). Here, we investigated if 12 weeks of progressive and explosive resistance training (PRT) increases rate of force...... development of ankle dorsiflexors (RFDdf), improves gait function and affects passive ankle joint stiffness in adults with CP.Thirty-five adults (age 36.5; range: 18-59 years) with CP were non-randomly assigned to a PRT or non-training control (CON) group in this explorative trial. The PRT group trained ankle...

  7. Ulcer pain in patients with venous leg ulcers related to antibiotic treatment and compression therapy.

    Science.gov (United States)

    Akesson, Nina; Oien, Rut Frank; Forssell, Henrik; Fagerström, Cecilia

    2014-09-01

    The aim of this study was to compare venous leg ulcer patients with and without ulcer pain to see whether ulcer pain affected the use of antibiotic treatment and compression therapy throughout healing. A total of 431 patients with venous leg ulcers were included during the study period. Every patient was registered in a national quality registry for patients with hard-to-heal leg, foot, and pressure ulcers. A high incidence of ulcer pain (57%) was found when the patients entered the study. Patients with ulcer pain had been treated more extensively with antibiotics both before and during the study period. Throughout healing there was a significant reduction of antibiotic use among patients in the 'no pain' group, from 44% to 23% (P=0.008). There was no significant difference between the two groups concerning compression therapy (85% vs. 88%), but 12% of patients in the 'pain' group did not get their prescribed compression compared with 6% of patients in the 'no pain' group. The groups did not differ significantly in terms of ulcer duration, ulcer size or healing time. This study shows a high incidence of ulcer pain, confirming that pain has a great impact on patients with venous leg ulcers. Results further suggest that the presence of ulcer pain increases the prescription of antibiotics but does not affect the use of compression therapy. Several advantages were found from using a national quality registry. The registry is a valuable clinical tool showing the importance of accurate diagnosis and effective treatment.

  8. Is preeclampsia associated with restless legs syndrome?

    OpenAIRE

    Ramirez, J O; Cabrera, S A S; Hidalgo, H; Cabrera, S G; Linnebank, M; Bassetti, C L; Kallweit, U

    2013-01-01

    OBJECTIVE: Restless legs syndrome (RLS) is a common neurologic disorder. Secondary RLS includes pregnancy and iron deficiency. Prevalence of RLS in pregnancy ranges from 11% to 27%. We aimed to assess the frequency and characteristics of RLS in pregnancy in a Peruvian population and to evaluate the possible pregnancy or delivery complications due to RLS. METHODS: We assessed 218 consecutive expectant mothers at the inpatient clinic of the Hospital San Bartolome in Lima, Peru. Assessment wa...

  9. Genetic aspects of restless legs syndrome

    OpenAIRE

    Dhawan, V; Ali, M; Chaudhuri, K R

    2006-01-01

    Restless legs syndrome (RLS), also known as Ekbom syndrome, is a common movement disorder with sensorimotor symptoms occurring during sleep and quiet wakefulness. The underlying cause for RLS is unknown but genetic influences play a strong part in the pathogenesis of RLS, particularly when the condition starts at a young age. This review explores the genetic basis of RLS and related phenotypic variations. Recently, three loci showing vulnerability to RLS have been described in French‐Canadian...

  10. Restless legs syndrome and pregnancy: A review

    OpenAIRE

    Srivanitchapoom, Prachaya; Pandey, Sanjay; Hallett, Mark

    2014-01-01

    Restless legs syndrome (RLS) is a common sensorimotor neurological disorder that is diagnosed according to the revised criteria of the International RLS Study Group (IRLSSG). The pathophysiology of RLS is still unknown and its prevalence is influenced by ethnicity, age, and gender. RLS is divided into two types by etiology: primary or idiopathic and secondary. Primary RLS is strongly influenced by a genetic component while secondary RLS is caused by other associated conditions such as end-sta...

  11. Effect of armor and carrying load on body balance and leg muscle function.

    Science.gov (United States)

    Park, Huiju; Branson, Donna; Kim, Seonyoung; Warren, Aric; Jacobson, Bert; Petrova, Adriana; Peksoz, Semra; Kamenidis, Panagiotis

    2014-01-01

    This study investigated the impact of weight and weight distribution of body armor and load carriage on static body balance and leg muscle function. A series of human performance tests were conducted with seven male, healthy, right-handed military students in seven garment conditions with varying weight and weight distributions. Static body balance was assessed by analyzing the trajectory of center of plantar pressure and symmetry of weight bearing in the feet. Leg muscle functions were assessed by analyzing the peak electromyography amplitude of four selected leg muscles during walking. Results of this study showed that uneven weight distribution of garment and load beyond an additional 9 kg impaired static body balance as evidenced by increased sway of center of plantar pressure and asymmetry of weight bearing in the feet. Added weight on non-dominant side of the body created greater impediment to static balance. Increased garment weight also elevated peak EMG amplitude in the rectus femoris to maintain body balance and in the medial gastrocnemius to increase propulsive force. Negative impacts on balance and leg muscle function with increased carrying loads, particularly with an uneven weight distribution, should be stressed to soldiers, designers, and sports enthusiasts. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Sleep board review question: restless legs

    Directory of Open Access Journals (Sweden)

    Omobomi O

    2018-02-01

    Full Text Available No abstract available. Article truncated after 150 words. Ms. Jones (not her real name is a 63-year-old woman who states that she gets very fidgety when sitting in a theater, watching a movie or when flying long distances on a plane. She is unable to find words to describe the sensation but she states that moving her legs make them feel better. Lately, she has been getting this feeling almost every night. She reports no leg discomfort in the daytime. She denies muscle cramps her legs. She had some recent investigations done by her primary care physician because of complaints of fatigue. Which of the following will be helpful in the diagnosis and management in this patient? 1. An overnight polysomnogram showing apnea hypopnea index of 1.6 events per hour and no periodic limb movements (PLMs 2. Ferritin level of 18 ng/ml (normal range 20-200 ng/ml 3. Serum Bicarbonate of 29 mEq/L (normal range 23-29 mEq/L 4. Thyroid …

  13. Restless Legs Syndrome Among the Elderly

    Directory of Open Access Journals (Sweden)

    Pei-Hao Chen

    2009-12-01

    Full Text Available Restless legs syndrome is a sleep and movement disorder that affects 5–15% of the general population, with an increased prevalence among the elderly population. It not only affects quality of life but also increases risk of mortality among older adults. The diagnosis is based on clinical symptoms of the patient by four minimal essential criteria. Restless legs syndrome can be divided into primary or secondary causes. Examination should be performed to rule out potentially treatable illnesses, such as iron deficiency, renal failure or peripheral neuropathy, especially among elderly patients. The initial approach to restless legs syndrome should be nonpharmacologic management, such as good sleep hygiene, regular exercise, cognitive behavioral therapy and avoidance of certain aggravating drugs. An algorithm based on scientific evidence and expert opinion was developed for guidance of treatment. Combination or change of medication can be applied to resistant or difficult cases. Since elderly patients are prone to treatment-related side effects, the best strategy is to start medication cautiously and at the lowest recommended dosage.

  14. Relationships between ground reaction force parameters during a sit-to-stand movement and physical activity and falling risk of the elderly and a comparison of the movement characteristics between the young and the elderly.

    Science.gov (United States)

    Yamada, Takayoshi; Demura, Shin-ichi

    2009-01-01

    This study aimed to examine the relationships between ground reaction force during a sit-to-stand (STS) movement and physical activity and falling risk of the elderly and the difference of the movement characteristics between the young and the elderly. Sixty elderly females who can achieve a STS movement by themselves and 30 healthy young females were measured for ground reaction force during STS movement from a chair, adjusted for lower leg length height. The elderly's physical activity and falling risk were also assessed. Physical activity and falling risk significantly correlated with parameters on force exertion during hip lift-off and knee-hip joint extension phases (|r|=0.26-0.41). Significant differences were found in ground reaction force parameters of all phases between the young and the elderly and STS movement of the elderly was suggested to result in poor force exertion and slowing down. The above tendency was noticeable in the hip lift-off and knee-hip joint extension phases. In conclusion, force exertion in hip lift-off and knee-hip joint extension phases of STS movement is related to physical activity and falling risk in the elderly. These phases may be useful to evaluate the elderly's physical activity and falling risk.

  15. Do ground reaction forces during unilateral and bilateral movements exhibit compensation strategies following ACL reconstruction?

    NARCIS (Netherlands)

    Baumgart, Christian; Schubert, Markus; Hoppe, Matthias W.; Gokeler, Alli; Freiwald, Juergen

    The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces (GRFs) during unilateral and bilateral movements of different knee loads in anterior cruciate ligament (ACL) reconstructed patients and (2) to investigate differences in leg asymmetry depending on the

  16. Leg position influences early blood loss and functional recovery following total knee arthroplasty: A randomized study.

    Science.gov (United States)

    Yang, Yang; Yong-Ming, Lv; Pei-jian, Ding; Jia, Li; Ying-ze, Zhang

    2015-11-01

    Hidden blood loss is a major factor influencing functional recovery and quality of life in patients undergoing total knee arthroplasty. Special hip and knee flexion positions after have been reported to have promising results with respect to reducing perioperative blood loss. The purpose of this study was to determine the effect of postoperative leg position on blood loss and functional recovery after total knee arthroplasty. We enrolled 46 consecutive patients with degenerative osteoarthritis of the knee in this prospective, randomized study. The patients were randomly allocated to a flexion or an extension group. In the flexion group, the affected leg was elevated by 60° at the hip, and the knee was flexed by 60°, while in the extension group, the affected knee was fully extended postoperatively. Blood loss, hemoglobin level, knee circumference and range of motion (ROM) were recorded to determine the influence of postoperative leg position on clinical outcomes. Although the transfusion rate was similar between the two groups (P > 0.05), other parameters related to blood loss (including calculated blood loss, hidden blood loss and postoperative knee circumference) were significantly lower in the flexion group than in the extension group (P group had gained a better ROM in the affected knee than had patients from the extension group (P = 0.04). At 6 months, however, the ROM of the affected knee was similar in both groups. The hospital stay was 1.9 days shorter in the flexion group than in the extension group. Wound infection rates were similar in both groups, and no proven case of deep vein thrombosis was observed in either group. Elevation of the hip by 60° with 60° knee flexion is an effective and simple method to reduce blood loss after primary unilateral total knee arthroplasty, and contributes to better recovery of the functional ROM in the early postoperative period. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights

  17. Can't Curb the Urge to Move? Living with Restless Legs Syndrome

    Science.gov (United States)

    ... Sleep? Wise Choices Recognizing Restless Legs Restless legs syndrome brings all 4 of these characteristics: A strong urge to move your legs, often with unpleasant feelings like tingling, burning or throbbing in the legs. Symptoms that get better ... Legs Syndrome Fact Sheet What Is Restless Legs Syndrome? Brain ...

  18. Restless Legs Syndrome and Leg Motor Restlessness in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Keisuke Suzuki

    2015-01-01

    Full Text Available Sleep disturbances are important nonmotor symptoms in Parkinson’s disease (PD that are associated with a negative impact on quality of life. Restless legs syndrome (RLS, which is characterized by an urge to move the legs accompanied by abnormal leg sensations, can coexist with PD, although the pathophysiology of these disorders appears to be different. RLS and PD both respond favorably to dopaminergic treatment, and several investigators have reported a significant relationship between RLS and PD. Sensory symptoms, pain, motor restlessness, akathisia, and the wearing-off phenomenon observed in PD should be differentiated from RLS. RLS in PD may be confounded by chronic dopaminergic treatment; thus, more studies are needed to investigate RLS in drug-naïve patients with PD. Recently, leg motor restlessness (LMR, which is characterized by an urge to move the legs that does not fulfill the diagnostic criteria for RLS, has been reported to be observed more frequently in de novo patients with PD than in age-matched healthy controls, suggesting that LMR may be a part of sensorimotor symptoms intrinsic to PD. In this paper, we provide an overview of RLS, LMR, and PD and of the relationships among these disorders.

  19. A Case of Painless Legs and Moving Toes Syndrome in Parkinson’s Disease Responsive to Dopaminergic Therapy

    Directory of Open Access Journals (Sweden)

    Sumihiro Kawajiri

    2016-01-01

    Full Text Available Painless Legs and Moving Toes Syndrome (PoLMT is a rare movement disorder characterized by flexion, extension, abduction, adduction, and torsion of toes without pain. It is considered a variant of Painful Legs and Moving Toes Syndrome (PLMT, which is characterized by similar movements but with pain. Although neuropathy and several central nervous system (CNS involvements have been reported to be associated with PoLMT, the actual cause and mechanism remain unclear. Here we describe the first case of PoLMT in Parkinson’s Disease (PD, parallel to parkinsonism in severity, who demonstrated a good response to dopaminergic therapy.

  20. Effect of Renal Transplantation in Restless Legs Syndrome.

    Science.gov (United States)

    Kahvecioglu, Serdar; Yildiz, Demet; Buyukkoyuncu, Nilufer; Celik, Huseyin; Tufan, Fatih; Kılıç, Ahmet Kasım; Gul, Bulent; Yildiz, Abdulmecid

    2016-02-01

    Restless legs syndrome is a disorder in which patients have irresistible urge to move legs during rest. Restless legs syndrome seems to be common in end-stage renal disease. After a successful renal transplant, symptoms ameliorate with renal function improvement and restless legs syndrome is seen less in this population. Here, we aimed to investigate restless legs syndrome frequency and associated factors in renal transplant patients. In a cross-sectional study with 193 patients (116 hemodialysis patients, 45 transplant patients, and 32 controls), the presence of restless legs syndrome was assessed using the Restless Legs Syndrome Questionnaire. Medical history, demographic, and laboratory data were collected from the patients' medical records. Patients were questioned about the presence of restless legs syndrome using the Restless Legs Syndrome Questionnaire. Patients were evaluated with Beck Depression Scale for depression and Pittsburgh tests for sleep disturbances. While the rate of restless legs syndrome was similar between transplants and controls, it was significantly greater in hemodialysis patients. Hemodialysis patients and controls had similar depression scores that were higher compared with transplant patients. Pittsburgh score was similar in transplant patients and controls and significantly increased in the hemodialysis patients. The rate of insomnia was significantly higher in the hemodialysis patients compared with the other 2 groups. Logistic regression analysis revealed independent correlates of restless legs syndrome as insomnia, Beck depression score, and being on hemodialysis. Linear regression analysis showed that independent correlates of higher Pittsburgh score were higher depression score, higher age, and presence of restless legs syndrome. The prevalence of restless legs syndrome is significantly lower in transplant patients than it is in patients on maintenance dialysis. In renal transplant patients, restless legs syndrome frequency was

  1. Leg movements during wakefulness in restless legs syndrome: time structure and relationships with periodic leg movements during sleep.

    Science.gov (United States)

    Ferri, Raffaele; Manconi, Mauro; Plazzi, Giuseppe; Bruni, Oliviero; Cosentino, Filomena I I; Ferini-Strambi, Luigi; Zucconi, Marco

    2012-05-01

    Approximately one third of patients with restless legs syndrome (RLS) also show periodic leg movements (PLM) during relaxed wake fulness (PLMW). In contrast with the large amount of data published on periodic leg movements during sleep (PLMS), PLMW have received less attention from the scientific community. The objective of this study was to evaluate the correlations/differences of time-structure and response to a dopamine-agonist between PLMW and PLMS in patients with RLS. Ninety idiopathic RLS patients and 28 controls were recruited. Subjects underwent clinical and neurophysiological evaluation, hematological screening, and one or two consecutive full-night polysomnographic studies. A subset of patients received 0.25mg of pramipexole or placebo before the second recording. Polysomnographic recordings were scored and LM activity was analyzed during sleep and during the epochs of wakefulness occurring during the first recording hour. RLS patients had higher LM activity during wakefulness than controls, but with a similar periodicity. Even if correlated, the ability of the PLMW index to predict the PLMS index decreased with increasing LM activity. Intermovement intervals during wakefulness showed one peak only at approximately 4s, gradually decreasing with increasing interval in both patients and controls. The effect of pramipexole was very limited and involved the small periodic portion of LM activity during wakefulness. PLMW index and PLMS index were correlated; however, the magnitude of this correlation was not sufficient to suggest that PLMW can be good predictors of PLMS. Short-interval LM activity during wakefulness and sleep might be linked to the severity of sleep disruption in RLS patients and the differences between their features obtained during wakefulness or sleep might be relevant for the diagnosis of sleep disturbances in RLS. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Restless legs syndrome and nocturnal leg cramps: a review and guide to diagnosis and treatment.

    Science.gov (United States)

    Tipton, Philip W; Wszołek, Zbigniew K

    2017-12-22

    Restless legs syndrome (RLS) and nocturnal leg cramps (NLCs) are common disorders affecting 7.0% and 24.1% of the population in some European countries, respectively. Patients suffering from RLS experience uncomfortable nocturnal sensations in the legs with the urge to move that dissipates while moving. NLC is characterized by abrupt muscle contraction, most often in the gastrocnemius or foot muscles, which occurs at night and may result in significant sleep disturbances. The diagnosis of these disorders has presented a challenge to health care providers because of symptom overlap with other sensory and motor disturbances with nocturnal predominance. Treatment options and approaches are lacking, partially because of our currently incomplete understanding of the pathophysiological mechanisms underlying these conditions. We reviewed the medical literature to provide a comprehensive assessment of RLS and NLC with a focus on improved diagnostic accuracy and treatment approaches.

  3. Lower Leg Morphology and Stretch-Shortening Cycle Performance of Dancers.

    Science.gov (United States)

    Rice, Paige E; van Werkhoven, Herman; Merritt, Edward K; McBride, Jeffrey M

    2018-01-24

    Greater levels of bone ultimate fracture load, bone stress-strain index, muscle cross-sectional area, and maximal voluntary isometric plantarflexion strength of the lower leg may be adaptations from chronic exposure to stretch-shortening cycle (SSC) actions. Dancers, a population that habitually performs SSC movements primarily about the ankle-joint, may serve as a novel population to gain broader understanding of SSC function. Ten female collegiate dancers and ten untrained controls underwent peripheral quantitative computed tomography scans of both lower legs and performed maximal voluntary isometric plantarflexions, countermovement hops and drop hops at 20 cm, 30 cm and 40 cm on a custom-made inclined sled. Dancers had greater right and left ultimate fracture load values and significantly (p ≤ 0.05) greater left leg stress-strain index than controls. Dancers had significantly larger right and left muscle cross-sectional area and maximal voluntary isometric plantarflexion values and hopped significantly higher during all hopping conditions in comparison to controls. Average force- and power-time curves revealed significantly greater relative force and power measurements during the concentric phase for all hopping conditions in dancers when compared to controls. This investigation provides evidence that dance may be a stimulus for positive muscle and bone adaptations, strength levels and enhanced SSC capabilities.

  4. The Effect of Single-Leg Stance on Dancer and Control Group Static Balance.

    Science.gov (United States)

    Kilroy, Elisabeth A; Crabtree, Olivia M; Crosby, Brittany; Parker, Amanda; Barfield, William R

    The purpose of this study was to compare kinetic differences of static balance between female dancers (D) with at least seven years of dance experience and female non-dancers (ND) who were typical college students. Participants were tested in single-leg stance. Both the dominant leg (DL) and non-dominant leg (NDL) were tested with the participants shod (S) and barefoot (BF). Kinetic variables (vertical, medio-lateral [ML], antero-posterior [AP] maximum ground reaction forces (GRF), and center of pressure (COP) ML and AP) were measured by a Bertec force platform at 1000 Hz with participants S and BF. Each subject's stance was measured over 3 × 30-second intervals. No significant differences (p≥0.05) existed between groups for height, body mass, or age. Significant differences existed between groups for balance time, AP GRF in both BF and S conditions for both DL and NDL, and ML GRF in BF NDL and S DL and NDL conditions. D and ND in BF and S conditions with DL and NDL static stance demonstrate different AP and ML GRF when balancing over a 30-second time interval. Data may suggest that ND are more prone to lose their balance. Further investigation is warranted to understand whether individuals in the rehabilitative field and athletic populations can use dance therapy for injury prevention and rehabilitation.

  5. Performance Calculation of Floating Wind Turbine Tension Leg Platform in the South China Sea

    Directory of Open Access Journals (Sweden)

    Hai Feng Wang

    2015-10-01

    Full Text Available The harvesting of wind energy is expected to increase greatly in the future because of its stability, abundance, and renewability in large coastal states such as China. The floating support structure will likely become the major structural form for wind turbines in the future due to its cost advantages when the water depth reaches 50 m. The 5MW wind turbine model from National Renewable Energy Lab (NREL and the modified tension leg platform model proposed by Harbin Institute of Technology (HIT were applied to certain sea conditions in the South China Sea in order to consider the effects of external load coupling actions. In this study, the internal force, mooring system force, as well as the acceleration, displacement and velocity of the floating structure of the modified HIT Tension Leg Platform (HIT-TLP were calculated. During this process, the physical parameters of its tension leg structure at a specific frequency domain were obtained to find the technical reserves for its practical application in the future.

  6. Forces in yeast flocculation

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stéphane P.; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N.; Dufrêne, Yves F.

    2015-01-01

    In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion (``flocculation'') is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.

  7. Actigraphic assessment of periodic leg movements in patients with restless legs syndrome.

    Science.gov (United States)

    Cippà, Maria A T; Baumann, Christian R; Siccoli, Massimiliano M; Bassetti, Claudio L; Poryazova, Rositsa; Werth, Esther

    2013-10-01

    The diagnosis of restless legs syndrome (RLS) relies upon diagnostic criteria which are based on history only, and dopaminergic treatment is not normally the first choice of treatment for all patients. It would be worthwhile to identify patients non-responsive to dopaminergic treatment beforehand, because they may suffer from a restless legs-like syndrome and may require alternative treatment. We included retrospectively 24 adult patients fulfilling the four essential criteria for restless legs and 12 age-matched healthy controls. They were investigated by ambulatory actigraphy from both legs over three nights, and patients started treatment with dopamine agonists after this diagnostic work-up. We examined 12 responders to dopaminergic treatment and 12 non-responders and studied the association between response to dopaminergic treatment and the periodic limb movement index (PLMI) as assessed with actigraphy. Demographic characteristics, excessive daytime sleepiness and fatigue at baseline were similar in all three groups. Baseline RLS severity was similar between responders and non-responders [International Restless Legs Severity Scale (IRLS): 25 ± 9 and 24 ± 8]. Group comparisons of PLMI before treatment initiation showed significant differences between the three groups. Post-hoc pairwise comparisons revealed that healthy controls had significantly lower PLMI (4.9 ± 4.5) than responders (29.3 ± 22.7) and non-responders (13.3 ± 11.2). Similarly, the PLMI in responders was lower than in non-responders. PLMI day-to-day variability did not differ between responders and non-responders and there was no correlation between treatment effect, as assessed by the decrease of the IRLS and baseline PLMI. Our retrospective study indicates that actigraphy to assess periodic limb movements may contribute to a better diagnosis of dopamine-responsive restless legs syndrome. © 2013 European Sleep Research Society.

  8. Profile of altered brain iron acquisition in restless legs syndrome

    Science.gov (United States)

    Ponnuru, Padmavathi; Wang, Xin-Sheng; Patton, Stephanie M.; Allen, Richard P.; Earley, Christopher J.

    2011-01-01

    Restless legs syndrome is a neurological disorder characterized by an urgency to move the legs during periods of rest. Data from a variety of sources provide a compelling argument that the amount of iron in the brain is lower in individuals with restless legs syndrome compared with neurologically normal individuals. Moreover, a significant percentage of patients with restless legs syndrome are responsive to intravenous iron therapy. The mechanism underlying the decreased iron concentrations in restless legs syndrome brains is unknown. We hypothesize that the source of the brain iron deficit is at the blood–brain interface. Thus we analysed the expression of iron management proteins in the epithelial cells of the choroid plexus and the brain microvasculature in post-mortem tissues. The choroid plexus, obtained at autopsy, from 18 neurologically normal controls and 14 individuals who had primary restless legs syndrome was subjected to histochemical staining for iron and immunostaining for iron management proteins. Iron and heavy chain ferritin staining was reduced in the epithelial cells of choroid plexus in restless legs syndrome. Divalent metal transporter, ferroportin, transferrin and its receptor were upregulated in the choroid plexus in restless legs syndrome. Microvessels were isolated from the motor cortex of 11 restless legs syndrome and 14 control brains obtained at autopsy and quantitative immunoblot analyses was performed. Expression of heavy chain ferritin, transferrin and its receptor in the microvessels from restless legs syndrome was significantly decreased compared with the controls but divalent metal protein 1, ferroportin, prohepcidin, mitochondrial ferritin and light-chain ferritin remained unchanged. The presence of an iron regulatory protein was demonstrated in the brain microvasculature and the activity of this protein is decreased in restless legs syndrome; a finding similar to our earlier report in neuromelanin cells from the substantia

  9. A Range-Balanced Force: An Alternate Force Structure Adapted to New Defense Priorities

    Science.gov (United States)

    2013-06-01

    forces will likely feature two aircraft types not currently contemplated in Air Force budgets—a medium-range unmanned combat aerial vehi- cle ( UCAV ...Dassault nEURon UCAV , scheduled to fly in 2012, doing what they think America’s cutting-edge Air Force is “supposed to do.” That pres- sure includes the OSD...long-legged, stealthy UCAV will cer- tainly cause policy analysts, budget-waste cutters, and Congress to ask why the Air Force isn’t buying the same

  10. Predicting Diaphyseal Cortical Bone Status Using Measures of Muscle Force Capacity.

    Science.gov (United States)

    Higgins, Simon; Sokolowski, Chester M; Vishwanathan, Megha; Anderson, Jessica G; Schmidt, Michael D; Lewis, Richard D; Evans, Ellen M

    2018-02-16

    Muscle cross sectional area (MCSA) is often used as a surrogate for the forces applied to bones during physical activity. Though MCSA is a strong predictor of cortical bone status, its use makes assumptions about the relationship between muscle size and force that are inaccurate. Furthermore, to measure MCSA and other muscle force surrogates typically requires expensive and/or radiative laboratory equipment. Thus, this study aimed to determine whether clinical lab- and field-based methodologies for measuring muscular force capacity accounted for similar variance in diaphyseal cortical bone status as a commonly used muscular force surrogate; MCSA, at the mid-tibia in young men and women. Healthy young adults (n = 142, 19.7 ± 0.7 yo, 52.8% female) were assessed via peripheral quantitative computed tomography at the mid-tibia for cortical bone status and MCSA. Muscle force capacity was measured via Biodex dynamometer, Nottingham leg extensor power rig, and Vertec vertical jump. Regression analysis compared the independent variance predicted by each muscle force measure to that of MCSA, accounting for relevant confounders. MCSA, knee extension peak torque, and peak anaerobic power from vertical jump were independent predictors of select cortical structural outcomes (cortical thickness and area, periosteal and endosteal circumference, and estimated strength) accounting for up to 78.4% of the variance explained (all p<.05). However, cortical volumetric bone mineral density was unrelated to any measure or surrogate of muscle force capacity. MCSA is a strong independent predictor of cortical bone structure; however, both lab- and field-based measures of peak torque and/or peak anaerobic power are promising alternatives, explaining similar and sometimes greater variance than MCSA.

  11. Leg movement tracking in automatic video-based one-leg stance evaluation.

    Science.gov (United States)

    Kawa, Jacek; Stępień, Paula; Kapko, Wojciech; Niedziela, Aleksandra; Derejczyk, Jarosław

    2018-04-01

    Falls are a major risk in elder population. Early diagnosis is therefore an important step towards increasing the safety of elders. One of the common diagnostic tests is the Berg Balance Scale (BBS), consisting of 14 exercises arranged from the easiest (sitting-to-standing) to the most demanding (one-leg stance). In this study a novel approach to the automatic assessment of the time in which the patient can remain in the one-leg stance position without loosing balance is introduced. The data is collected using a regular video camera. No markers, special garments, or system calibration are required. Two groups are examined. The first group consists of 16 students: healthy, young adults (12 female, 4 male, avg. 20yrs±1). The second group consists of 50 elders (39 female, 11 male, avg. 78.8yrs±5.9). Data (short, one minute recordings) are collected in a controlled environment using a digital video recorder (50fps, 1920×1080) fixed to a tripod. Data are processed off-line. First, the region of interest is determined. Next, the Kanade-Lucas-Tomasi tracking is performed. Best tracks are selected based on the registered vertical movement and two tracks are obtained corresponding to the left and right leg movements. Tracks are later subjected to the sparse signal baseline estimation, denoising and thresholding to detect the raised leg. Results are compared frame-wise to the ground truth reference obtained in the manual processing procedure. Both legs are evaluated in the elder group (in all cases several attempts featuring both legs were registered), resulting in 89.18%±11.27% DICE, 93.07%±5.43% sensitivity and 96.94%±6.11% specificity values for both legs. The signal of a single leg is evaluated in the student group (in all cases only one attempt was needed to perform the full examination) resulting in 98.96%±1.2% DICE, 98.78%±1.65% sensitivity and 98.73%±2.69% specificity values. This is the first step towards a video-based system enabling the automatic

  12. Relationship between Leg Mass, Leg Composition and Foot Velocity on Kicking Accuracy in Australian Football.

    Science.gov (United States)

    Hart, Nicolas H; Nimphius, Sophia; Spiteri, Tania; Cochrane, Jodie L; Newton, Robert U

    2016-06-01

    Kicking a ball accurately over a desired distance to an intended target is arguably the most important skill to acquire in Australian Football. Therefore, understanding the potential mechanisms which underpin kicking accuracy is warranted. The aim of this study was to examine the relationship between leg mass, leg composition and foot velocity on kicking accuracy in Australian Football. Thirty-one Australian Footballers (n = 31; age: 22.1 ± 2.8 years; height: 1.81 ± 0.07 m; weight: 85.1 ± 13.0 kg; BMI: 25.9 ± 3.2) each performed ten drop punt kicks over twenty metres to a player target. Athletes were separated into accurate (n = 15) and inaccurate (n = 16) kicking groups. Leg mass characteristics were assessed using whole body DXA scans. Foot velocity was determined using a ten-camera optoelectronic, three-dimensional motion capture system. Interactions between leg mass and foot velocity evident within accurate kickers only (r = -0.670 to -0.701). Relative lean mass was positively correlated with kicking accuracy (r = 0.631), while no relationship between foot velocity and kicking accuracy was evident in isolation (r = -0.047 to -0.083). Given the evident importance of lean mass, and its interaction with foot velocity for accurate kickers; future research should explore speed-accuracy, impulse-variability, limb co-ordination and foot-ball interaction constructs in kicking using controlled with-in subject studies to examine the effects of resistance training and skill acquisition programs on the development of kicking accuracy. Key pointsAccurate kickers expressed a very strong inverse relationship between leg mass and foot velocity. Inaccurate kickers were unable to replicate this, with greater volatility in their performance, indicating an ability of accurate kickers to mediate foot velocity to compensate for leg mass in order to deliver the ball over the required distance.Accurate kickers exhibited larger quantities of relative lean mass and lower quantities

  13. A self-adjusting negative feedback joint controller for legs standing on moving substrates of unknown compliance

    Science.gov (United States)

    Schneider, Axel; Cruse, Holk; Fischer, Björn; Schmitz, Josef

    2007-05-01

    Some recent robot controllers for hexapod walking have been developed based on investigations of stick insects. These animals live in an unpredictable environment that consists of twigs and leaves. Supports like twigs, leaves and branches induce a considerable amount of movement to the legs and their elastic joints. Earlier studies proposed negative feedback PD-controllers to regulate the angles of the knee joints to handle this situation. Recent studies suggest that the behaviour of the joint controller depends on the compliance of the substrate the insect is standing on. On highly elastic substrates (e.g. leaves) the joint controller exhibits an I-characteristic. Deviations from the original position are compensated completely. On moderately elastic substrates (e.g. twigs) the joint controller comprises a P-characteristic. The leg attains a resting position that differs from the original position through application of a specific compensation force. On stiff substrates the knee joint seems to be controlled by a D-controller. If the leg endpoint is forced away from the original position by an external disturbance (e.g. a moving branch), the controller compensates this deviation by activation of the according muscle which results in a counter force. After some time the controller seems to "give up." The force decreases to zero. To model these results, we propose a self-adjusting joint controller that changes its own setpoint in dependance of the substrate stiffness. The substrate stiffness is determined by means of a correlator circuit that compares (superimposed) movement commands with the actual responses of the leg joint. The new controller can be used for the control of legged robots.

  14. Force Dynamics of Verb Complementation

    Directory of Open Access Journals (Sweden)

    Jacek Woźny

    2015-12-01

    Full Text Available Force Dynamics of Verb Complementation The concepts of motion and force are both extensively discussed in cognitive linguistics literature. But they are discussed separately. The first usually in the context of ‘motion situations’ (Talmy, Slobin, Zlatev, the other as part of the Force Dynamics framework, which was developed by Talmy. The aim of this paper is twofold: first, to argue that the concepts of force and motion should not be isolated but considered as two inseparable parts of force-motion events. The second goal is to prove that the modified Force Dynamics (force-motion framework can be used for precise characterization of the verb complementation patterns. To this end, a random sample of 50 sentences containing the verb ‘went’ is analyzed, demonstrating the differences between the categories of intensive and intransitive complementation with respect to the linguistically coded parameters of force and motion.

  15. On the biomimetic design of agile-robot legs.

    Science.gov (United States)

    Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

    2011-01-01

    The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

  16. On the Biomimetic Design of Agile-Robot Legs

    Directory of Open Access Journals (Sweden)

    Pablo Gonzalez-de-Santos

    2011-11-01

    Full Text Available The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

  17. Robust and efficient walking with spring-like legs

    International Nuclear Information System (INIS)

    Rummel, J; Blum, Y; Seyfarth, A

    2010-01-01

    The development of bipedal walking robots is inspired by human walking. A way of implementing walking could be performed by mimicking human leg dynamics. A fundamental model, representing human leg dynamics during walking and running, is the bipedal spring-mass model which is the basis for this paper. The aim of this study is the identification of leg parameters leading to a compromise between robustness and energy efficiency in walking. It is found that, compared to asymmetric walking, symmetric walking with flatter angles of attack reveals such a compromise. With increasing leg stiffness, energy efficiency increases continuously. However, robustness is the maximum at moderate leg stiffness and decreases slightly with increasing stiffness. Hence, an adjustable leg compliance would be preferred, which is adaptable to the environment. If the ground is even, a high leg stiffness leads to energy efficient walking. However, if external perturbations are expected, e.g. when the robot walks on uneven terrain, the leg should be softer and the angle of attack flatter. In the case of underactuated robots with constant physical springs, the leg stiffness should be larger than k-tilde = 14 in order to use the most robust gait. Soft legs, however, lack in both robustness and efficiency.

  18. On the Biomimetic Design of Agile-Robot Legs

    Science.gov (United States)

    Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

    2011-01-01

    The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented. PMID:22247667

  19. Leg stiffness and sprint ability in amputee sprinters.

    Science.gov (United States)

    Hobara, Hiroaki; Tominaga, Shuichi; Umezawa, Shingo; Iwashita, Koudai; Okino, Atsuo; Saito, Taku; Usui, Fumio; Ogata, Toru

    2012-09-01

    Understanding leg stiffness (K (leg)) in amputee sprinters is important for the evaluation of their sprint ability and development of running-specific prostheses (RSP). To investigate K (leg) during hopping in amputee sprinters. Cross-sectional study. Seven transtibial (TT) and seven transfemoral (TF) amputee sprinters, as well as seven non-active able-bodied subjects, performed one-legged hopping matching metronome beats at 2.2 Hz. Amputees hopped on their sound limb whereas able-bodied (AB) subjects hopped on their dominant limb. Using a spring-mass model, K (leg) was calculated from the subjects' body mass, ground contact and flight times. Both TT and TF sprinters demonstrated significantly higher K (leg) than AB subjects. K (leg) during hopping on the sound leg significantly correlated with personal records attained in a 100-m sprint in both TT (r = -0.757) and TF sprinters (r = -0.855). The results of the present study suggest that amputee sprinters have a greater K (leg) during hopping than inactive non-amputees, and that their sprint ability can be predicted from the K (leg) during hopping at 2.2 Hz on the sound limb.

  20. Job burnout and coping strategies among extension agents in south ...

    African Journals Online (AJOL)

    The need to maintain a non-mineral dependent economy and daunting food import bills have been the drive for the provision of extension services, which is dependent on motivated extension work force.. Extension personnel will not stay motivated under circumstances where the risk of job burnout is high. A simple random ...

  1. Association between serum hepcidin level and restless legs syndrome.

    Science.gov (United States)

    Dauvilliers, Yves; Chenini, Sofiene; Vialaret, Jérôme; Delaby, Constance; Guiraud, Lily; Gabelle, Audrey; Lopez, Regis; Hirtz, Christophe; Jaussent, Isabelle; Lehmann, Sylvain

    2018-02-08

    To better understand the role of iron homeostasis dysregulation in restless legs syndrome, we compared serum hepcidin and ferritin levels in drug-free patients with primary restless legs syndrome and healthy controls and studied the relationship between hepcidin level and restless legs syndrome severity. One hundred and eight drug-free patients with primary restless legs syndrome (65 women; median age, 61.5 years) and 45 controls (28 women; median age, 53.9 years) were enrolled. Inclusion criteria were: normal ferritin level (>50 ng/mL) and absence of iron disorders, chronic renal or liver failure, and inflammatory or neurological diseases. Each subject underwent a thorough clinical examination and a polysomnography assessment. Serum hepcidin-25 was quantified using a validated mass spectrometry method. Restless legs syndrome severity was evaluated according to the International Restless Legs Syndrome Study Group. Despite no group difference between normal ferritin levels and demographic features, serum hepcidin level and hepcidin/ferritin ratio were higher in patients than in controls. Hepcidin level and hepcidin/ferritin ratio, but not ferritin level, were positively correlated with periodic leg movements during sleep and wakefulness in the whole sample. Hepcidin level seem to be associated with restless legs syndrome severity in a complex U-shaped relationship, without relationship with age at restless legs syndrome onset, positive family history, sleep and depressive symptoms, genetic background, and polysomnographic measurements. No relationship was found between ferritin level and restless legs syndrome severity. In drug-free patients with primary restless legs syndrome, hepcidin level is higher than in controls and may be associated with restless legs syndrome clinical severity. This result emphasizes the complex peripheral iron metabolism deregulation in restless legs syndrome, opening potential perspectives for a personalized approach with a hepcidin

  2. Hamstrings co-activation in ACL-deficient subjects during isometric whole-leg extensions

    NARCIS (Netherlands)

    Aalbersberg, S.; Kingma, I.; van Dieen, J.H.

    2009-01-01

    It has been reported that anterior cruciate ligament (ACL)-deficient subjects increase the level of hamstrings activation and this has been interpreted as a means to cope with increased anterior tibial laxity in the knee. This study aimed to establish to what extent co-activation strategies in

  3. Biomechanical Comparison of Single- and Double-Leg Jump Landings in the Sagittal and Frontal Plane.

    Science.gov (United States)

    Taylor, Jeffrey B; Ford, Kevin R; Nguyen, Anh-Dung; Shultz, Sandra J

    2016-06-01

    Double-leg forward or drop-jump landing activities are typically used to screen for high-risk movement strategies and to determine the success of neuromuscular injury prevention programs. However, research suggests that these tasks that occur primarily in the sagittal plane may not adequately represent the lower extremity biomechanics that occur during unilateral foot contact or non-sagittal plane movements that are characteristic of many multidirectional sports. To examine the extent to which lower extremity biomechanics measured during a jump landing on a double leg (DL) after a sagittal plane (SAG) movement is representative of biomechanics measured during single-leg (SL) or frontal plane (FRONT) jump landing tasks. Controlled laboratory study. Lower extremity biomechanics were measured in 15 recreationally active females (mean age [±SD], 19.4 ± 2.1 years; mean height, 163.3 ± 5.9 cm; mean weight, 61.1 ± 7.1 kg) while performing SAGDL, SAGSL, FRONTDL, and FRONTSL jump landing tasks. Repeated-measures analyses of variance examined differences in lower extremity biomechanics between the 4 tasks, and linear regressions examined the extent to which an individual's biomechanics during SAGDL were representative of their biomechanics during SAGSL, FRONTDL, and FRONTSL. Lower extremity kinematics and kinetics differed by condition, with the SAGDL task generally eliciting greater hip and knee flexion angles and lower hip and knee forces than the other tasks (P plane jump landing tasks used to screen for ACL injury risk and the effectiveness of ACL injury prevention programs may not adequately represent the lower extremity biomechanics that occur during single-leg activities. These results support further investigation of single-leg multidirectional landings to identify high-risk movement strategies in female athletes playing multidirectional sports.

  4. Bilateral differences in muscle fascicle architecture are not related to the preferred leg in jumping athletes.

    Science.gov (United States)

    Aeles, Jeroen; Lenchant, Sietske; Vanlommel, Liesbeth; Vanwanseele, Benedicte

    2017-07-01

    In many sports, athletes have a preferred leg for sport-specific tasks, such as jumping, which leads to strength differences between both legs, yet the underlying changes in force-generating mechanical properties of the muscle remain unknown. The purpose of this study was to investigate whether the muscle architecture of the medial gastrocnemius (MG) is different between both legs in well-trained jumping athletes and untrained individuals. In addition, we investigated the effect of two ankle joint positions on ultrasound muscle architecture measurements. Muscle architecture of both legs was measured in 16 athletes and 11 untrained individuals at two ankle joint angles: one with the ankle joint in a tendon slack length (TSL) angle and one in a 90° angle. Fascicle lengths and pennation angles at TSL were not different between the preferred and non-preferred legs in either group. The comparison between groups showed no difference in fascicle length, but greater pennation angles were found in the athletes (21.7° ± 0.5°) compared to the untrained individuals (19.8° ± 0.6°). Analyses of the muscle architecture at a 90° angle yielded different results, mainly in the comparison between groups. These results provide only partial support for the notion of training-induced changes in muscle architecture as only differences in pennation angles were found between athletes and untrained individuals. Furthermore, our results provide support to the recommendation to take into account the tension-length relationship and to measure muscle architecture at individually determined tendon slack joint angles.

  5. Implementation of molecular dynamics and its extensions with the coarse-grained UNRES force field on massively parallel systems; towards millisecond-scale simulations of protein structure, dynamics, and thermodynamics.

    Science.gov (United States)

    Liwo, Adam; Ołdziej, Stanisław; Czaplewski, Cezary; Kleinerman, Dana S; Blood, Philip; Scheraga, Harold A

    2010-03-09

    We report the implementation of our united-residue UNRES force field for simulations of protein structure and dynamics with massively parallel architectures. In addition to coarse-grained parallelism already implemented in our previous work, in which each conformation was treated by a different task, we introduce a fine-grained level in which energy and gradient evaluation are split between several tasks. The Message Passing Interface (MPI) libraries have been utilized to construct the parallel code. The parallel performance of the code has been tested on a professional Beowulf cluster (Xeon Quad Core), a Cray XT3 supercomputer, and two IBM BlueGene/P supercomputers with canonical and replica-exchange molecular dynamics. With IBM BlueGene/P, about 50 % efficiency and 120-fold speed-up of the fine-grained part was achieved for a single trajectory of a 767-residue protein with use of 256 processors/trajectory. Because of averaging over the fast degrees of freedom, UNRES provides an effective 1000-fold speed-up compared to the experimental time scale and, therefore, enables us to effectively carry out millisecond-scale simulations of proteins with 500 and more amino-acid residues in days of wall-clock time.

  6. Multiple-step model-experiment matching allows precise definition of dynamical leg parameters in human running.

    Science.gov (United States)

    Ludwig, C; Grimmer, S; Seyfarth, A; Maus, H-M

    2012-09-21

    The spring-loaded inverted pendulum (SLIP) model is a well established model for describing bouncy gaits like human running. The notion of spring-like leg behavior has led many researchers to compute the corresponding parameters, predominantly stiffness, in various experimental setups and in various ways. However, different methods yield different results, making the comparison between studies difficult. Further, a model simulation with experimentally obtained leg parameters typically results in comparatively large differences between model and experimental center of mass trajectories. Here, we pursue the opposite approach which is calculating model parameters that allow reproduction of an experimental sequence of steps. In addition, to capture energy fluctuations, an extension of the SLIP (ESLIP) is required and presented. The excellent match of the models with the experiment validates the description of human running by the SLIP with the obtained parameters which we hence call dynamical leg parameters. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Sleep disturbances in restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Jović Jasmina

    2018-01-01

    Full Text Available Background/Aim. Resteless legs syndrome (RLS is chronical neurological disorder characterized by urge to move legs that is usually accompanied by unpleasant sensations in the lower extremities. Sleep disturbance is one of the main accompanying symptoms of RLS which exists in approximatelly 90% of patients. Impairment of sleep is related to daily sleepiness, depressive and anxiety disorders. The aim of this study was to detect frequency and characterisitics of sleep-related symptoms in patients with RLS, and its impairrment to daily sleepiness, fatique, anxiety and depression. Methods. We have examinated 94 patients with RLS. The diagnose of RLS was based on questionnaire with 4 specific questions according to the International Restless Legs Syndrome Study Group (IRLSSG criteria updated in 2003. Severity of symptoms was astimated with IRLSSG Rating Scale, depression and anxiety with Hamilton Depression Rating Scale (HDRS and Hamilton Anxiety Rating Scale (HARS and sleepiness with Epworth Sleepiness scale (ESS. We astimated sleep characteristics and disturbances with specific questionnaire. Results. In our study 79.9% of patients had sleep-related symptoms. Average sleep duration was 6.50 ± 1.42 hours, with average frequency of awakening 2.34 ± 1.69 times per night. Average ESS score was 5.12 ± 4.08 (0–17. Patients with more severe symptoms had higher degree of sleepiness (p = 0.005. Patients with higher symptoms frequency, significantly more often had sleep disturbance (p = 0.016, tiredness and daily sleepiness (p = 0.001. Daily sleepiness (ESS also significantly correlates with depression (p < 0.05 and anxiety (p = 0.012. Conclusion. Our results confirm that sleep disturbances are one of the key accompanying symptoms of RLS which cause daily sleepiness, tiredness, depression and anxiety. Therefore, their early recognition and appropriate treatment must be a priority in RLS patients.

  8. [Bow legged adjectives in ancient literature].

    Science.gov (United States)

    Simon, Frantisek; Steger, Florian

    2011-01-01

    This article addresses the issue of capturing the medical entity called 'curved legs' in a terminologically exact way. In so doing, it refers to the long-lasting process of differentiation of exact nuances of meaning in Ancient Greek and Latin. In the chronological perusal of ancient Greek literature, it becomes evident that the various adjectives employed are often vague when looking at non-medical literature. By contrast, in the Hippocratic corpus these terms are for the first time annotated with explanations intended to lead to a more precise understanding of the described deformity. Further attempts of differentiation can be found in the writings of Galen, who not only distinguishes between outward and inward curvatures, but also between deformities of the thigh and lower leg as well as between pathological and natural curvatures. Latin literature also provides a series of adjectives that were initially often used in the meaning of 'curved' but it was not until Celsus that these were differentiated with respect to the type and direction of the curvature. When comparing Greek and Latin adjectives, it turns out that though the Latin term blaesus can be traced back etymologically to the Greek word beta lambda alpha iota sigma ó zeta, the meaning of beta lambda alpha iota sigma ó zeta does not fully correspond to that of the Latin word. It is not before the later common transliteration of Greek words that this adjective took on the meaning of beta lambda alpha iota sigma ó zeta; however, this was finally lost again. In summary, the article concludes that exact word meanings in ancient literature are often unclear and precise ascriptions of meanings are inconsistent. In the case of "curved legs," this has led to misunderstandings regarding the respective types and directions of the curvature.

  9. Exploration of Planetary Terrains with a Legged Robot as a Scout Adjunct to a Rover

    Science.gov (United States)

    Colombano, Silvano; Kirchner, Frank; Spenneberg, Dirk; Hanratty, James

    2004-01-01

    The Scorpion robot is an innovative, biologically inspired 8-legged walking robot. It currently runs a novel approach to control which utilizes a central pattern generator (CPG) and local reflex action for each leg. From this starting point we are proposing to both extend the system's individual capabilities and its capacity to function as a "scout", cooperating with a larger wheeled rover. For this purpose we propose to develop a distributed system architecture that extends the system's capabilities both in the direction of high level planning and execution in collaboration with a rover, and in the direction of force-feedback based low level behaviors that will greatly enhance its ability to walk and climb in rough varied terrains. The final test of this improved ability will be a rappelling experiment where the Scorpion explores a steep cliff side in cooperation with a rover that serves as both anchor and planner/executive.

  10. Strategies for equilibrium maintenance during single leg standing on a wobble board

    DEFF Research Database (Denmark)

    Silva, Priscila de Brito; Oliveira, Anderson Souza; Mrachacz-Kersting, Natalie

    2016-01-01

    (p CoP and WB angular movement measures were weakly and not significantly correlated between tasks. This lack of correlation indicates that WB balance maintenance...... to calculate trunk and contralateral-leg excursion (EXC) and velocity (VEL), and center of pressure (CoP) EXC and VEL during FS on a force platform. From the WB test, standing time (WBTIME) was determined and the board's angular EXC and VEL were calculated from four markers on the WB as surrogate measures...... for CoP dynamics. Electromyographic average rectified values (ARV) from eight leg and thigh muscles of the supporting limb were calculated for both tasks. WB ARV amplitudes were normalized with respect to the value of FS ARV and presented significantly higher peroneus longus and biceps femoris activity...

  11. 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

    There is virtually no published information on muscle fatigue, defined as a gradual decline in force-generating capacity, during conventional dynamic (D) leg exercise. To quantitate progression of fatigue, we developed 1) a model featuring integration of maximal voluntary static contraction (MVC.......05) for matched DKE work rates. To track fatigue, MVC (90 degrees knee angle) was performed every 2 min of DKE. After 4 min of DKE at work rates corresponding to (mean +/- SE) 66 +/- 2, 78 +/- 2, and 100% of peak DKE O2 uptake, MVC fell to 95 +/- 3, 90 +/- 5, and 65 +/- 7%* of MVC of rested muscle, respectively...... (*P fatigue during D leg exercise provides a framework to study the effects of a variety...

  12. Single-leg landing neuromechanical data following load and land height manipulations

    Directory of Open Access Journals (Sweden)

    Andrew D. Nordin

    2016-09-01

    Full Text Available Lower extremity sagittal kinematic and kinetic data are summarized alongside electrical muscle activities during single-leg landing trials completed in contrasting external load and landing height conditions. Nineteen subjects were analyzed during 9 landing trials in each of 6 experimental conditions computed as percentages of subject anthropometrics (bodyweight: BW and subject height: H; BW, BW+12.5%, BW+25%, and H12.5%, H25%. Twelve lower extremity variables (sagittal hip, knee, ankle angles and moments, vertical ground reaction force (GRFz, gluteus maximus, biceps femoris, vastus medials, medial gastrocnemius, and tibialis anterior muscles were assessed using separate principal component analyses (PCA. Variable trends across conditions were summarized in “Neuromechanical synergies in single-leg landing reveal changes in movement control. Human Movement Science” (Nordin and Dufek, 2016 [1], revealing changes in landing biomechanics and movement control.

  13. An anterior cruciate ligament injury does not affect the neuromuscular function of the non-injured leg except for dynamic balance and voluntary quadriceps activation.

    Science.gov (United States)

    Zult, Tjerk; Gokeler, Alli; van Raay, Jos J A M; Brouwer, Reinoud W; Zijdewind, Inge; Hortobágyi, Tibor

    2017-01-01

    The function of the anterior cruciate ligament (ACL) patients' non-injured leg is relevant in light of the high incidence of secondary ACL injuries on the contralateral side. However, the non-injured leg's function has only been examined for a selected number of neuromuscular outcomes and often without appropriate control groups. We measured a broad array of neuromuscular functions between legs of ACL patients and compared outcomes to age, sex, and physical activity matched controls. Thirty-two ACL-deficient patients (208 ± 145 days post-injury) and active and less-active controls (N = 20 each) participated in the study. We measured single- and multi-joint neuromuscular function in both legs in each group and expressed the overall neuromuscular function in each leg by calculating a mean z-score across all neuromuscular measures. A group by leg MANOVA and ANOVA were performed to examine group and leg differences for the selected outcomes. After an ACL injury, duration (-4.3 h/week) and level (Tegner activity score of -3.9) of sports activity decreased and was comparable to less-active controls. ACL patients showed bilateral impairments in the star excursion balance test compared to both control groups (P ≤ 0.004) and for central activation ratio compared to active controls (P ≤ 0.002). There were between-leg differences within each group for maximal quadriceps and hamstring strength, voluntary quadriceps activation, star excursion balance test performance, and single-leg hop distance (all P quadriceps force accuracy and variability, knee joint proprioception, and static balance. Overall neuromuscular function (mean z-score) did not differ between groups, but ACL patients' non-injured leg displayed better neuromuscular function than the injured leg (P quadriceps activation, ACL patients had no bilateral neuromuscular deficits despite reductions in physical activity after injury. Therapists can use the non-injured leg as a reference to assess the

  14. Consistent force fields for saccharides

    DEFF Research Database (Denmark)

    Rasmussen, Kjeld

    1999-01-01

    Consistent force fields for carbohydrates were hitherto developed by extensive optimization ofpotential energy function parameters on experimental data and on ab initio results. A wide range of experimental data is used: internal structures obtained from gas phase electron diffraction and from x......-anomeric effects are accounted for without addition of specific terms. The work is done in the framework of the Consistent Force Field which originatedin Israel and was further developed in Denmark. The actual methods and strategies employed havebeen described previously. Extensive testing of the force field...

  15. Giant VAC in a patient with extensive necrotizing fasciitis.

    Science.gov (United States)

    Steinstraesser, Lars; Sand, Michael; Steinau, Hans-Ulrich

    2009-03-01

    The authors present a case of an extensive fulminant necrotizing fasciitis of the left flank, thigh, and lower parts of the leg treated with debridement, split-thickness skin grafting, and a giant negative pressure wound dressing covering 0.53 m( 2) or 18% of the body surface. To the authors' knowledge, this is the largest split-thickness grafted body surface successfully treated with negative pressure wound dressing documented in the literature.

  16. Pseudo Algebraically Closed Extensions

    Science.gov (United States)

    Bary-Soroker, Lior

    2009-07-01

    This PhD deals with the notion of pseudo algebraically closed (PAC) extensions of fields. It develops a group-theoretic machinery, based on a generalization of embedding problems, to study these extensions. Perhaps the main result is that although there are many PAC extensions, the Galois closure of a proper PAC extension is separably closed. The dissertation also contains the following subjects. The group theoretical counterpart of pseudo algebraically closed extensions, the so-called projective pairs. Applications to seemingly unrelated subjects, e.g., an analog of Dirichlet's theorem about primes in arithmetic progression for polynomial rings in one variable over infinite fields.

  17. Nice snake, shame about the legs.

    Science.gov (United States)

    Coates; Ruta

    2000-12-01

    Snakes are one of the most extraordinary groups of terrestrial vertebrates, with numerous specializations distinguishing them from other squamates (lizards and their allies). Their musculoskeletal system allows creeping, burrowing, swimming and even gliding, and their predatory habits are aided by chemo- and thermoreceptors, an extraordinary degree of cranial kinesis and, sometimes, powerful venoms. Recent discoveries of indisputable early fossil snakes with posterior legs are generating intense debate about the evolutionary origin of these reptiles. New cladistic analyses dispute the precise significance and phylogenetic placement of these fossils. These conflicting hypotheses imply radically different scenarios of snake origins and relationships with wide biological implications.

  18. Leg ulcer in lepromatous leprosy - Case report*

    Science.gov (United States)

    Fernandes, Tania Rita Moreno de Oliveira; dos Santos, Talita Suzany Siqueira; Lopes, Ramon Rodrigues de Macedo

    2016-01-01

    In Brazil, leprosy is a widespread infectious and contagious disease. Clinicians and specialists view leprosy broadly as a systemic infection, since, in its manifestations, it mimics many conditions, such as rheumatic, vascular, ENT, neurological and dermatological diseases. There are few studies that characterize the factors associated with ulcers in leprosy. These injuries should be prevented and treated promptly to avoid serious problems like secondary infections, sepsis, carcinomatous degeneration and amputations. We describe a patient with ulcers on his legs, involving late diagnosis of lepromatous leprosy. PMID:27828650

  19. Painful legs and moving toes syndrome

    Directory of Open Access Journals (Sweden)

    Qiu-ying Ma

    2015-10-01

    Full Text Available Painful legs and moving toes syndrome (PLMT is a rare movement disorder with low diagnostic rate, which is characterized by lower limb pain with involuntary movements of feet or toes. Etiology and pathogenesis of this disease is still unclear. Patients have different clinical manifestations, so the diagnosis is difficult. Treatment methods for PLMT are numerous, but so far the treatment of this disease is still a major challenge for clinicians. Further research is still needed to guide clinical work. DOI: 10.3969/j.issn.1672-6731.2015.10.013

  20. Labor Force

    Science.gov (United States)

    Occupational Outlook Quarterly, 2012

    2012-01-01

    The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two…

  1. One-Leg Standing Time of the Affected Side Moderately Predicts for Postdischarge Falls in Community Stroke Patients.

    Science.gov (United States)

    Yoshimoto, Yoshinobu; Oyama, Yukitsuna; Tanaka, Mamoru; Sakamoto, Asuka

    2016-08-01

    The purpose of the present study was to investigate the predictive accuracy of one-leg standing time at hospital discharge on falls in stroke patients. This was a retrospective cohort study. Participants included stroke patients (n = 65) who could walk when discharged from inpatient rehabilitation ward. To investigate the relationship between one-leg standing time and falls, logistic analysis was utilized with a criterion variable including the presence or absence of falls after 1-year hospital discharge as well as explanatory variables including Brunnstrom stage, knee extension strength on the affected side, Barthel Index, 10-m walking speed, and one-leg standing time on both sides. The accuracy of prediction by one-leg standing time was measured by the area under the curve of the receiver operating characteristic curve. Among the 65 patients, 38 (58.5%) experienced a fall 1 year after discharge. One-leg standing time of the affected side was not significantly associated with the falls (odds ratio: .89; 95% confidence interval: .79-1.01). When the fall incidents were assessed by area under the curve of the receiver operating characteristic curve, one-leg standing time of the affected side was observed to have increased marginally to .93 (95% confidence interval: .87-.99) as compared to the traditional prediction mode area under the curve (area under the curve .88; 95% confidence interval: .81-.97). One-leg standing time of the affected side may be considered as a moderately effective and simple assessment method for predicting postdischarge falls in a clinical setting. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Restless Legs Syndrome After Single Low Dose Quetiapine Administration.

    Science.gov (United States)

    Soyata, Ahmet Z; Celebi, Fahri; Yargc, Lutfi I

    2016-01-01

    Restless legs syndrome is an underdiagnosed sensori-motor disorder and psychotropic drugs are one of the main secondary causes of the illness. The most common psychotropic agents that cause restless legs syndrome are antidepressants; however, antipsychotics have also been reported to induce restless legs syndrome. The prevalence, vulnerability factors and the underlying mechanism of antipsychotic-induced restless legs syndrome are unclear. A possible explanation is that dopaminergic blockade is the main precipitator of the syndrome. Quetiapine-induced restless legs syndrome is another point of interest because of its low binding to D2 receptors. We herein report the case of a restless legs syndrome that emerged after a single low dose quetiapine administration.

  3. Immediate Effect of Positioning Devices on Infant Leg Movement Characteristics.

    Science.gov (United States)

    Jiang, Crystal; de Armendi, Joyce T; Smith, Beth A

    2016-01-01

    To determine the immediate effects of constraining or encouraging positioning devices on leg movement of infants with typical development (TD) and at-risk for developmental delay (AR). Twenty-six infants (13 TD, 13 AR) were placed in the supine position, a jungle gym, or a car seat. Movement sensors on infants' ankles measured acceleration and angular velocity. We calculated the number of leg movements, peak acceleration, and peak rotational rate of each leg movement. A 2 (group) × 3 (condition) analysis of variance with repeated measures on condition tested for a group effect, a condition effect, and a group by condition interaction for leg movement quantity, average peak acceleration, and average peak rotation. Leg movement quantity and average peak acceleration were significantly lower for the car seat condition compared with the supine position or the gym. Positioning device use has an immediate effect on infant leg movement characteristics. Long-term effects remain unknown.

  4. Greater bilateral deficit in leg press than in handgrip exercise might be linked to differences in postural stability requirements.

    Science.gov (United States)

    Magnus, Charlene R A; Farthing, Jonathan P

    2008-12-01

    Bilateral deficit is defined as the difference in the summed force between contracting muscles alone and contracting contralateral homologous muscles in combination. The purpose of the study was to investigate how postural stability influences bilateral deficit by comparing an exercise requiring more postural stability (the leg press) with an exercise requiring less postural stability (the handgrip). Eight participants volunteered for the study (3 males, 5 females). Maximal strength was determined by a 1-repetition maximum for the leg press (weight machine) and handgrip (dynamometer) exercises. Electromyography was used to measure activation of the effectors (flexor carpi ulnaris for the handgrip and vastus lateralis for the leg press) and the core muscles (rectus abdominis and external obliques). Bilateral deficit was greater in the leg press (-12.08 +/- 10.22%) than the handgrip (-0.677 +/- 5.00%; p < 0.05). Muscle activation of the effectors and core muscles was not significantly different between unilateral and bilateral conditions for either exercise. However, core muscle activation was significantly greater during the leg press (48.30 +/- 19.60 microV) than during the handgrip (16.50 +/- 8.10 microV; p < 0.05) exercise. These results support the hypothesis that an exercise requiring more postural stability (e.g., the leg press) will have a larger deficit and greater activation of core muscles than an exercise requiring less postural stability (e.g., the handgrip). Since the bilateral deficit was only apparent for the leg press exercise, we conclude that postural stability requirements might influence the magnitude of bilateral deficit.

  5. Minimizing the cost of locomotion with inclined trunk predicts crouched leg kinematics of small birds at realistic levels of elastic recoil.

    Science.gov (United States)

    Rode, Christian; Sutedja, Yefta; Kilbourne, Brandon M; Blickhan, Reinhard; Andrada, Emanuel

    2016-02-01

    Small birds move with pronograde trunk orientation and crouched legs. Although the pronograde trunk has been suggested to be beneficial for grounded running, the cause(s) of the specific leg kinematics are unknown. Here we show that three charadriiform bird species (northern lapwing, oystercatcher, and avocet; great examples of closely related species that differ remarkably in their hind limb design) move their leg segments during stance in a way that minimizes the cost of locomotion. We imposed measured trunk motions and ground reaction forces on a kinematic model of the birds. The model was used to search for leg configurations that minimize leg work that accounts for two factors: elastic recoil in the intertarsal joint, and cheaper negative muscle work relative to positive muscle work. A physiological level of elasticity (∼ 0.6) yielded segment motions that match the experimental data best, with a root mean square of angular deviations of ∼ 2.1 deg. This finding suggests that the exploitation of elastic recoil shapes the crouched leg kinematics of small birds under the constraint of pronograde trunk motion. Considering that an upright trunk and more extended legs likely decrease the cost of locomotion, our results imply that the cost of locomotion is a secondary movement criterion for small birds. Scaling arguments suggest that our approach may be utilized to provide new insights into the motion of extinct species such as dinosaurs. © 2016. Published by The Company of Biologists Ltd.

  6. Nocturnal leg cramps in children: incidence and clinical characteristics.

    Science.gov (United States)

    Leung, A. K.; Wong, B. E.; Chan, P. Y.; Cho, H. Y.

    1999-01-01

    The records of 2527 healthy children seen in an ambulatory care clinic were evaluated for nocturnal leg cramps in the preceding 12 months, frequency and duration of the cramps, whether the cramps affected one leg or both legs at a time, whether there was associated muscle cramps in feet, whether the cramps occurred when the child was awake or asleep, and whether there was residual tenderness in the affected muscles. Nocturnal leg cramps were present in 185 children for an overall incidence of 7.3%. Leg cramps were noted only in children aged > or = 8 years. The incidence increased at 12 years and peaked at 16 to 18 years of age. A majority (81.6%) of the affected children had nocturnal leg cramps 1 to 4 times per year. The mean duration of episodes was 1.7 minutes. Leg cramps were unilateral in 98.9% of cases and the ipsilateral foot also was involved in 18.9% of cases. One hundred thirty-five (73%) children had leg cramps while asleep, and the remaining 23 (12.4%) children had leg cramps in either state. Fifty-seven (30.8%) children had residual tenderness in the affected muscles. The mean duration of residual tenderness was 33.2 minutes (range: 2 minutes-1 day). We conclude that nocturnal leg cramps are common in children aged > 12 years. A majority of the affected children have leg cramps 1 to 4 times per year. The cramps are usually unilateral and occur when the children are asleep. Normal duration of the leg cramp is < 2 minutes. Residual tenderness is present in approximately 30% of the affected children. Residual tenderness, if present, usually lasts for half an hour. PMID:10388258

  7. Severe Pelvic Obliquity Affects Femoral Offset in Patients with Total Hip Arthroplasty but Not Leg-Length Inequality.

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Zhou

    Full Text Available Leg-length inequality is an extensively studied complication of total hip arthroplasty in normal patients. However, few studies have focused on the pelvic obliquity of coronal pelvic malrotation. We hypothesized that pelvic obliquity with a fixed abduction/adduction contracture deformity of the hip may intraoperatively affect the release of soft tissues, ultimately resulting in a leg-length inequality. This study also investigated whether the femoral and vertical offsets of total hip arthroplasty were correlated with pelvic obliquity. This prospective study divided 98 patients into six groups based on the inclination of pelvic obliquity before total hip arthroplasty. Leg-length inequality, variation of pelvic obliquity, offset, and vertical offset were measured after total hip arthroplasty. Leg-length inequality and vertical offset were not significantly different among groups, whereas the variation of pelvic obliquity was significantly higher in type IIC pelvic obliquity than in other groups. Type IC pelvic obliquity had a significantly shorter offset than did the other groups, which may have been an important factor leading to type IC pelvic obliquity. Pelvic obliquity exhibited no significant effect on leg-length inequality in patients with total hip arthroplasty. A shorter offset may be caused by the higher tension of the abductor in the operated hip, which may result in the formation of type IC pelvic obliquity. Releasing the abductor contracture and restoring femoral offset are important for increasing hip stability and maintaining pelvic balance following total hip arthroplasty.

  8. Severe Pelvic Obliquity Affects Femoral Offset in Patients with Total Hip Arthroplasty but Not Leg-Length Inequality.

    Science.gov (United States)

    Zhou, Xiaoxiao; Wang, Qi; Zhang, Xianlong; Chen, Yunsu; Peng, Xiaochun; Mao, Yuanqing; Yang, Yang; Fu, Beigang; Wang, Xiuhui; Tang, Tingting

    2015-01-01

    Leg-length inequality is an extensively studied complication of total hip arthroplasty in normal patients. However, few studies have focused on the pelvic obliquity of coronal pelvic malrotation. We hypothesized that pelvic obliquity with a fixed abduction/adduction contracture deformity of the hip may intraoperatively affect the release of soft tissues, ultimately resulting in a leg-length inequality. This study also investigated whether the femoral and vertical offsets of total hip arthroplasty were correlated with pelvic obliquity. This prospective study divided 98 patients into six groups based on the inclination of pelvic obliquity before total hip arthroplasty. Leg-length inequality, variation of pelvic obliquity, offset, and vertical offset were measured after total hip arthroplasty. Leg-length inequality and vertical offset were not significantly different among groups, whereas the variation of pelvic obliquity was significantly higher in type IIC pelvic obliquity than in other groups. Type IC pelvic obliquity had a significantly shorter offset than did the other groups, which may have been an important factor leading to type IC pelvic obliquity. Pelvic obliquity exhibited no significant effect on leg-length inequality in patients with total hip arthroplasty. A shorter offset may be caused by the higher tension of the abductor in the operated hip, which may result in the formation of type IC pelvic obliquity. Releasing the abductor contracture and restoring femoral offset are important for increasing hip stability and maintaining pelvic balance following total hip arthroplasty.

  9. Six weeks' aerobic retraining after two weeks' immobilization restores leg lean mass and aerobic capacity but does not fully rehabilitate leg strenght in young and older men

    DEFF Research Database (Denmark)

    Vigelsø Hansen, Andreas; Gram, Martin; Wiuff, Caroline

    2015-01-01

    OBJECTIVE: To determine the effect of aerobic retraining as rehabilitation after short-term leg immobilization on leg strength, leg work capacity, leg lean mass, leg muscle fibre type composition and leg capillary supply, in young and older men. SUBJECTS AND DESIGN: Seventeen young (23 ± 1 years...... immobilization had marked effects on leg strength, and work capacity and 6 weeks' retraining was sufficient to increase, but not completely rehabilitate, muscle strength, and to rehabilitate aerobic work capacity and leg lean mass (in the young men)....

  10. An Ultralightweight and Living Legged Robot.

    Science.gov (United States)

    Vo Doan, Tat Thang; Tan, Melvin Y W; Bui, Xuan Hien; Sato, Hirotaka

    2018-02-01

    In this study, we describe the most ultralightweight living legged robot to date that makes it a strong candidate for a search and rescue mission. The robot is a living beetle with a wireless electronic backpack stimulator mounted on its thorax. Inheriting from the living insect, the robot employs a compliant body made of soft actuators, rigid exoskeletons, and flexure hinges. Such structure would allow the robot to easily adapt to any complex terrain due to the benefit of soft interface, self-balance, and self-adaptation of the insect without any complex controller. The antenna stimulation enables the robot to perform not only left/right turning but also backward walking and even cessation of walking. We were also able to grade the turning and backward walking speeds by changing the stimulation frequency. The power required to drive the robot is low as the power consumption of the antenna stimulation is in the order of hundreds of microwatts. In contrast to the traditional legged robots, this robot is of low cost, easy to construct, simple to control, and has ultralow power consumption.

  11. Restless legs syndrome in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Shahram Rafie

    2016-01-01

    Full Text Available Restless legs syndrome (RLS is a neurological disorder characterized by uncomfortable sensation of paresthesia in legs that subsequently causes involuntary and continuous movement of the lower limbs, especially at rest. Its prevalence in hemodialysis is more than that in the general population. Different risk factors have been suggested for RLS. We studied the prevalence and risk factors of RLS in 137 hemodialysis patients followed up at our center. The patients completed at least three months on dialysis and fulfilled four criteria for the diagnosis of RLS. We compared the patients with and without RLS, and the odds ratios (ORs were estimated by the logistic regression models. The prevalence of RLS was 36.5% in the study patients. Among the variables, diabetes was the only predicting factor for the development of RLS. The diabetic patients may be afflicted with RLS 2.25 times more than the non-diabetics. Women developed severe RLS 5.23 times more than men. Neurodegeneration, decrease in dopamine level, higher total oxidant status, and neuropathy in diabetic patients may explain the RLS symptoms.

  12. Compression Stockings for Treating Venous Leg Ulcers

    Directory of Open Access Journals (Sweden)

    J. P. Benigni

    2013-01-01

    Full Text Available Background. In order to treat venous leg ulcers, it is recommended to use high pressure compression (30–40 mmHg at the ankle. Compression stockings which are not operator dependant could be the best option because of their pressure control. However 30–40 mmHg compression stockings are often hard to put on. Putting two lower pressure compression stockings over each other could be a good therapeutic alternative. Objectives. To compare the in vitro pressures given by the manufacturers of 2 antiulcer kits with the in vivo interface pressures measured in healthy subjects and to evaluate the stiffness and friction indices from those kits based on the interface pressure in order to assess their clinical properties. Material and Methods. Using a Kikuhime pressure device, interface pressure was measured in 12 healthy subjects at the reference point B1. One stiffness index (Static Stiffness Index (SSI and a friction index have been calculated. Results. Mediven Ulcer kit gets the recommended pressures whereas Jobst’s Ulcer Care kit does not for treating a venous leg ulcer. Jobst’s Ulcer Care transmits entirely the pressure in relation to a friction index close to 1. Conclusion. This antiulcer kit study underlines that in vivo and in vitro pressures can be different (Jobst’s Ulcer Care kit and Mediven Ulcer kit. In order not to lose pressure, it is important to take into account the friction index when superimposing two stockings.

  13. Dispersion Forces

    CERN Document Server

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  14. Leg Rejuvenation: A Combination Approach: A Review and Our Experience.

    Science.gov (United States)

    Weiss, Margaret; Mahoney, Anne M; Gold, Michael; Lawrence, Naomi

    2016-05-01

    Patients increasingly seek to enhance the appearance of their legs. Elimination of unwanted leg veins, reduction of epidermal photo-aging changes such as solar lentigines and keratoses, tightening of skin laxity and reduction of adipose tissue are among the most commonly requested goals. Many patients require a combination approach to address their concerns. It is important for dermatologists to be aware of the multitude of procedures that can be performed, often in combination, to rejuvenate the leg. The purpose of this review article was to discuss procedures for improving the appearance of the leg and to share the authors experience, especially in the combination approach to leg rejuvenation. A literature search was performed to investigate cosmetic procedures being performed on the leg, with an emphasis on controlled or randomized studies. In addition, the authors contributed their personal experience. Our discussion of the literature review highlights the treatments for leg veins, unwanted fat, cellulite, and photodamage of the legs that are most supported in peer-reviewed publications. A synergistic, combination approach to leg rejuvenation works best. This includes the use of injectable agents, energy-based devices, and more invasive surgical procedures.

  15. Kinematic analysis of leg alignment during conventional versus navigated total knee arthroplasty: Initial results of a prospective study

    Directory of Open Access Journals (Sweden)

    Chih-Wei Chang

    2012-09-01

    Full Text Available Current kinematic navigation systems provide real-time spatial analyses of leg alignments during total knee arthroplasty (TKA instead of delayed radiographic verification after surgery. A prospective study was conducted to investigate leg alignments of TKAs that underwent different surgical guidance [intramedullary (IM jig-based vs. navigation-assisted] using a kinematic navigation system. Since May 2007, patients admitted for primary TKA were considered for inclusion. Within 6 months, 38 sets of intraoperative analyses on the operated legs have been performed. Excluding seven unreliable data sets, 15 conventional IM jig-based TKAs and 16 navigation-assisted TKAs were available. The leg alignments in maximum knee extension were retrieved for comparison. Although similar final coronal alignments were accurately achieved in both groups (0.21 valgus in the IM group vs. 0.17 valgus in the NA group, p=0.993, a more flexed sagittal axis was constructed with conventional IM jigs (1.93 flexion in the IM group vs. 0.58 extension in the NA group, p<0.05. The study suggests that comparable coronal precision could be achieved with conventional IM jigs by trained surgeons, although computer-assisted navigation is a documented method to restore accurate alignment. Different sagittal alignments observed in this study indicate the inherent discrepancy between different surgical guides as well as their according concepts.

  16. Summertime blues? A re-examination of the seasonality of web searches for restless legs and leg cramps.

    Science.gov (United States)

    O'Keeffe, Shaun T

    2017-09-01

    Studies that examined Internet searches for restless legs and leg cramps have found a strong seasonal effect with peaks in summer and troughs in winter months. The present study used an econometric approach to examine the seasonality of such searches in greater detail. Monthly relative search volumes for 'restless legs' and 'leg cramps' from 2004 to March 2017 in the United Kingdom (UK) and Australia were obtained from Google Trends. Average percentage change from winter to summer months was examined. The TRAMO-SEATS procedure from the DEMETRA statistical software was used to decompose the data into trend, seasonal and noise components and to determine whether a combined seasonality test was positive. There were substantial percentage increases in Google Trends searches between winter and summer months regarding restless legs in the UK (median increase 46%) and Australia (33%) and regarding leg cramps in the UK (95%) and Australia (50%). However, the combined seasonality test was positive only for leg cramps and not for restless legs in both countries: although there was significant stable seasonality in restless legs searches, this was outweighed by substantial moving seasonality and noise components. Examination of average percentage increase in search volume from winter to summer exaggerates the degree of seasonality. Seasonal effects for restless legs searches are non-significant when the trend and noise components of the data are considered, although this does not exclude a clinical significance for the identified stable seasonality. Significant seasonality, with a summer peak, is present for leg cramps searches and suggests an increase in the incidence or severity of leg cramps in summer. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Balancing Control of AIT Leg Exoskeleton Using ZMP based FLC

    Directory of Open Access Journals (Sweden)

    Narong Aphiratsakun

    2009-12-01

    Full Text Available This paper is focused on the use of Zero Moment Point (ZMP concept for balancing control of the Asian Institute of Technology Leg EXoskeleton-I (ALEX-I. ALEX-I has been developed to assist patients who suffer from paraplegia or immobility due to the loss of power on lower limbs. The balanced posture set-points (joint trajectories under ZMP criterion are generated offline. The ZMP based set points are provided as the desired postures to ALEX-I. Fuzzy Logic Controller (FLC determines the modified set points based on postures balancing sensed by loadcells. Ground Contact Point (GCP is used to find the “ZMP-like in real time”. GCP data is obtained by placing 4 loadcells forming a force plate on each foot of ALEX-I. This GCP data is then compared with the reference ZMP. Uncertainties of the model parameters, backlash, and joint tolerance are considered as disturbance. The differences of ZMP and GCP on x-z plane are used as the inputs to the FLC. The 4 outputs from FLC are the compensated angles of left and right ankles joints in roll and pitch axes that make the actual ZMP locate in the convex hull of the supporting area.

  18. Towards Biomimetic Virtual Constraint Control of a Powered Prosthetic Leg.

    Science.gov (United States)

    Gregg, Robert D; Sensinger, Jonathon W

    2014-01-01

    This brief presents a novel control strategy for a powered prosthetic ankle based on a biomimetic virtual constraint. We first derive a kinematic constraint for the "effective shape" of the human ankle-foot complex during locomotion. This shape characterizes ankle motion as a function of the Center of Pressure (COP)-the point on the foot sole where the resultant ground reaction force is imparted. Since the COP moves monotonically from heel to toe during steady walking, we adopt the COP as a mechanical representation of the gait cycle phase in an autonomous feedback controller. We show that our kinematic constraint can be enforced as a virtual constraint by an output linearizing controller that uses only feedback available to sensors onboard a prosthetic leg. Using simulations of a passive walking model with feet, we show that this novel controller exactly enforces the desired effective shape whereas a standard impedance (i.e., proportional-derivative) controller cannot. This work provides a single, biomimetic control law for the entire single-support period during robot-assisted locomotion.

  19. X-pod: a small footprint multi-legged piezoelectric single-crystal unimorph-based actuator concept

    Science.gov (United States)

    Shukla, Rahul; Lim, Leong-Chew; Gandhi, Prasanna

    2012-06-01

    Multi-legged piezoelectric single-crystal actuators with small footprints using an X-pod approach, namely, the Tripod and Tetrapod, have been conceptualized, each leg being a unimorph driven by Pb(Zn1/3Nb2/3)O3-(6-7)%PbTiO3 (PZN-(6-7)%PT) single crystals of [110]L × [001]T cut. Both finite-element analysis and experimental investigations are carried out to evaluate the performance of the Tripod and Tetrapod actuators. When operated at 0.57 kV mm-1, both actuators exhibit an axial displacement of nearly 60 µm. Blocking forces of about 10 N and 14 N are observed for the Tripod and the Tetrapod, respectively. The blocking forces are roughly doubled if the perfectly clamped condition is imposed for the legs at the pedestal end while the axial displacement is lowered marginally by 12%. In addition to small footprints, other attractive features of the actuators include greater flexibility to modify the leg geometry and their inclination to suit the application.

  20. Evaluation of the effectiveness of toe board energy-absorbing material for foot, ankle, and lower leg injury reduction.

    Science.gov (United States)

    Patalak, John P; Stitzel, Joel D

    2018-02-17

    Since 2000, numerous improvements have been made to the National Association for Stock Car Auto Racing, Incorporated (NASCAR®) driver restraint system, resulting in improved crash protection for motorsports drivers. Advancements have included seats, head and neck restraints (HNRs), seat belt restraint systems, driver helmets, and others. These enhancements have increased protection for drivers from severe crash loading. Extending protection to the driver's extremities remains challenging. Though the drivers' legs are well contained for lateral and vertical crashes, they remain largely unrestrained in frontal and frontal oblique crashes. Sled testing was conducted for the evaluation of an energy-absorbing (EA) toe board material to be used as a countermeasure for leg and foot injuries. Testing included baseline rigid toe boards, tests with EA material-covered toe boards, and pretest positioning of the 50th percentile male frontal Hybrid III anthropomorphic test device (ATD) lower extremities. ATD leg and foot instrumentation included foot acceleration and tibia forces and moments. The sled test data were evaluated using established injury criteria for tibial plateau fractures, leg shaft fractures, and calcaneus, talus, ankle, and midfoot fractures. A polyurethane EA foam was found to be effective in limiting axial tibia force and foot accelerations when subjected to frontal impacts using the NASCAR motorsport restraint system.

  1. Less extensive surgery compared to extensive surgery

    DEFF Research Database (Denmark)

    Lauszus, Finn F; Petersen, Astrid Christine; Neumann, Gudrun

    2014-01-01

    in postmenopausal women was associated with surgery including hysterectomy and bilateral oophorectomy (pcarcinoma was found 138 times (95% CI: 48, 275) more prevalent than the expected rate. CONCLUSION......: The survival of women was better in AGCT than in epithelial ovarian tumor. Age and type of surgery, besides stage, influenced survival. Total abdominal hysterectomy and bilateral salpingo-oophorectomy is the recommended treatment with advancing age. At younger age less extensive surgery was associated...

  2. Marketing Extension Needs for Sustainable Extension Practices ...

    African Journals Online (AJOL)

    However, Age (ƒÓ2 =39.33;ƒâ>0.05), religion (ƒÓ2 =2.752; ƒâ >0.05) and cassava association membership (ƒÓ2= 3.438, ƒâ>0.05) were not significant. Therefore, agricultural marketing techniques should be incorporated into agricultural extension delivery packages to ensure continuous farming practices and adoption of ...

  3. Forced marriage.

    Science.gov (United States)

    2007-06-01

    Guidelines to help A&E staff and other healthcare professionals who suspect cases of forced marriage were launched this month by the government. The guidelines provide practical advice on how to recognise the warning signs, and what to do if patients disclose that they have been, or are about to be, forced to marry. The guidelines, Dealing with Cases of Forced Marriage, are available at www.fco.gov.uk/forcedmarriage.

  4. Effects of vibration training on force production in female basketball players.

    Science.gov (United States)

    Fernandez-Rio, Javier; Terrados, Nicolas; Fernandez-Garcia, Benjamin; Suman, Oscar E

    2010-05-01

    The goal of this research project was to investigate the long-term effects of whole-body vibration (WBV) training on force production. Thirty-one female basketball players were randomly distributed in an experimental group: VG (vibration) and a control group: CG (no vibration). Both groups participated in the same training program; however, the experimental group (VG) performed a set of exercises on a vibration platform (Power Plate) at 30- to 35-Hz frequency and 4 mm amplitude, whereas the CG performed the same exercises at 0 Hz. Muscle performance of the legs was tested on a contact-time platform (Ergojump, Finland) through several tests: squat jump (SJ), countermovement jump (CMJ), and 15-second maximal performance jump; squat leg power (knee extension) was also evaluated using an Ergopower machine (Bosco, Italy). After 14 weeks, there was a significant increase (p training has no additive or discernible effect on the strength development of female basketball players after several weeks of use, suggesting that the application of this technology has no advantages over traditional strength training methods.

  5. Priorities for Extension.

    Science.gov (United States)

    Hayward, J. A.

    Agricultural extension is one component in an array including research, training, education, marketing, international trade, etc. which develop together to bring about growth, and sustained growth determines the priorities for extension. These priorities depend inevitably on the stage of development of a country or region, and on the current…

  6. Gabapentin Enacarbil: Pharmacotherapy of Restless Legs Syndrome

    Directory of Open Access Journals (Sweden)

    Ruth Jones

    2010-01-01

    Full Text Available Restless Legs Syndrome (RLS is a prevalent sleep-associated movement disorder greatly affecting patients’ quality of life (QoL. Several drugs can be used to control this condition although the first-line dopamine agents often cause adverse effects. Non-dopaminergic drugs such as oral gabapentin (GBP have been more recently advocated. Despite ameliorating RLS symptoms, GBP's pharmacokinetic limitations restrict its overall effectiveness. A novel specifically designed prodrug, gabapentin enacarbil (GE, has demonstrated successful RLS alleviation with a superior pharmacokinetic profile. This review aims to examine the efficacy and tolerability of both GBP and GE as pharmacotherapy for RLS. Despite some heterogeneity and limitations across research methodologies, GE appears to be a potential RLS therapy superior to GBP and other dopaminergic agents.

  7. [Lipedema of the leg associated with dermatomyositis].

    Science.gov (United States)

    Ignjatović, M; Cerović, S

    1999-01-01

    Lipedema represents a form of lipodistrophy, which consists of abnormal accumulation of fat in subcutaneous tissue of the lower limbs with consecutive development of lymphostasis and lymphedema. The aim of this article was to review one clear case of lower limbs lipedema, of unusual occurrence and appearance, which was associated with dermatomyositis. A moderately manifested lipedema in 8 years old little girl was reported with its expressive segmental distribution to upper and lower legs, without significant increase in its size during last 10 years and without signs of lymphostasis. The hereditary influence was not confirmed. Histological examination of lipedematous tissue revealed significant presentation of immune component of the disease. According to the available literature, association between lipedema and dermatomyositis, lower limbs lipedema with segmental distribution as noticed above and its appearance as a consequence of corticosteroid therapy have not yet been published.

  8. [Pseudo-radicular referred leg pain].

    Science.gov (United States)

    von Heymann, W

    2015-12-01

    Pseudo-radicular leg pain as initially described by Bruegger more than 55 years ago was at that time a genius explanation for so many non-radicular pain syndromes that needed not any kind of surgical intervention but in first line a manual treatment or a treatment by therapeutic local anesthetics. Today we describe this pain as a "referred pain" originating from other anatomic structures that may occur during the development of chronic pain. Nevertheless this pain is found in many patients and it still seems to be a big problem for many physicians and surgeons. Imaging does not help either. The history and the clinical symptoms, the examinations, the chain reactions in the motor system as well as the treatment options from the point of view of manual medicine are described.

  9. Endovenous management of venous leg ulcers.

    Science.gov (United States)

    Raju, Seshadri; Kirk, Orla K; Jones, Tamekia L

    2013-04-01

    Compression is the current "standard" in the treatment of venous leg ulcers, and corrective surgery is ancillary. The emergence of safe and effective minimally invasive corrective techniques prompts a reappraisal of this paradigm. Among 192 consecutive limbs with venous leg ulcers, 189 were treated by (1) endovenous laser ablation (n = 30), (2) iliac vein stent placement (n = 89), or (3) both (n = 69). Residual deep reflux was not treated. No specialized wound care was used, and 38% of patients did not use stockings. Outcome measures were time to heal the ulcer and cumulative long-term healing. Sixty percent of the limbs were post-thrombotic. The median reflux segment score was 3 (range, 0-7). Thirty-seven percent had deep axial reflux. Median intravascular ultrasound-detected stenosis was 70% (range, 0%-100%) in stented patients. Sensitivity of venography to iliac vein obstruction was 52%. Postprocedural mortality was 0%, and 2% had deep venous thrombosis (ulcers approximately ≤1 inch in diameter had healed. Larger ulcers were slower in healing (P pressure). However, long-term ulcer healing was inferior in limbs with reflux segment score of ≥3 (P ulcers in this consecutive series achieved long-term healing with the described minimally invasive algorithm. Uncorrected residual reflux was not an impediment to ulcer healing. Ulcers sized ≤1 inch required no specialized or prolonged wound care. Compression was not necessary to achieve or maintain healing after interventional correction. Copyright © 2013 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  10. Restless legs syndrome in patients on hemodialysis

    Directory of Open Access Journals (Sweden)

    Saleh Mohammad Yaser Salman

    2011-01-01

    Full Text Available Restless legs syndrome (RLS is common among dialysis patients, with a reported prevalence of 6-60%. The prevalence of RLS in Syrian patients on hemodialysis (HD is not known. The purpose of this study is to determine the prevalence of RLS in patients on regular HD, and to find the possible correlation between the presence of RLS and demographic, clinical, and biochemical factors. One hundred and twenty-three patients (male/female = 70/53, mean age = 41.95 ± 15.11 years on HD therapy at the Aleppo University Hospital were enrolled into the study. RLS was diagnosed based on criteria established by the International Restless Legs Syn-drome Study Group (IRLSSG. Data procured were compared between patients with and without RLS. Applying the IRLSSG criteria for the diagnosis, RLS was seen in 20.3% of the study pa-tients. No significant difference in age, gender, and intake of nicotine and caffeine was found between patients with and without the RLS. Similarly, there was no difference between the two groups in the duration of end-stage renal disease (ESRD, the period of dialysis dependence, dialysis adequacy, urea and creatinine levels, and the presence of anemia. The co-morbidities and the use of drugs also did not differ in the two groups. Our study suggests that the high prevalence of RLS among patients on HD requires careful attention and correct diagnosis can lead to better therapy and better quality of life. The pathogenesis of RLS is not clear and further studies are required to identify any possible cause as well as to discover the impact of this syndrome on sleep, quality of life, and possibly other complications such as cardiovasculare disease.

  11. ODYSSEUS autonomous walking robot: The leg/arm design

    Science.gov (United States)

    Bourbakis, N. G.; Maas, M.; Tascillo, A.; Vandewinckel, C.

    1994-01-01

    ODYSSEUS is an autonomous walking robot, which makes use of three wheels and three legs for its movement in the free navigation space. More specifically, it makes use of its autonomous wheels to move around in an environment where the surface is smooth and not uneven. However, in the case that there are small height obstacles, stairs, or small height unevenness in the navigation environment, the robot makes use of both wheels and legs to travel efficiently. In this paper we present the detailed hardware design and the simulated behavior of the extended leg/arm part of the robot, since it plays a very significant role in the robot actions (movements, selection of objects, etc.). In particular, the leg/arm consists of three major parts: The first part is a pipe attached to the robot base with a flexible 3-D joint. This pipe has a rotated bar as an extended part, which terminates in a 3-D flexible joint. The second part of the leg/arm is also a pipe similar to the first. The extended bar of the second part ends at a 2-D joint. The last part of the leg/arm is a clip-hand. It is used for selecting several small weight and size objects, and when it is in a 'closed' mode, it is used as a supporting part of the robot leg. The entire leg/arm part is controlled and synchronized by a microcontroller (68CH11) attached to the robot base.

  12. Impact of Restless Legs Syndrome on Cardiovascular Autonomic Control.

    Science.gov (United States)

    Bertisch, Suzanne M; Muresan, Cristen; Schoerning, Laura; Winkelman, John W; Taylor, J Andrew

    2016-03-01

    To examine whether patients with restless legs syndrome demonstrate specific alterations in cardiovascular autonomic control. Patients with moderate-severe restless legs syndrome (n = 20, 80% female) and controls (n = 20) matched for age, sex, body mass index, and free of hypertension and cardiovascular disease were enrolled. We assessed cardiovagal baroreflex gain via the modified Oxford technique, sympathetically mediated vascular responses to isometric exercise to fatigue, bradycardiac response to Valsalva maneuver, and respiratory sinus arrhythmia during paced breathing. Standard electrocardiography, beat-by-beat arterial pressure, respiration, and popliteal blood flow velocity were recorded continuously. Resting blood pressure and heart rate were similar between groups. However, baroreflex gain averaged 14.3 ± 1.4 msec/mm Hg in restless legs syndrome and was lower than in controls (22.6 ± 3.5 msec/mm Hg, P = 0.04). Hemodynamic responses to isometric exercise were similar between groups, though participants with restless legs syndrome had lower leg blood flow (P leg vascular resistance (P restless legs syndrome demonstrate compromised cardiovagal control, specific to the arterial baroreflex, with greater peripheral vascular resistance, potentially due to heightened sympathetic outflow. These autonomic alterations may directly relate to the higher prevalence of cardiovascular disease in restless legs syndrome. © 2016 Associated Professional Sleep Societies, LLC.

  13. Criteria in diagnosing nocturnal leg cramps : A systematic review

    NARCIS (Netherlands)

    Hallegraeff, Joannes; de Greef, Mathieu; Krijnen, Wim; van der Schans, Cees

    2017-01-01

    Background: Up to 33% of the general population over 50 years of age are affected by nocturnal leg cramps. Currently there are no generally accepted clinical characteristics, which identify nocturnal leg cramps. This study aims to identify these clinical characteristics and to differentiate between

  14. How Can I Relieve My Pregnancy Leg Cramps?

    Science.gov (United States)

    ... Español How Can I Relieve My Pregnancy Leg Cramps? KidsHealth / For Parents / How Can I Relieve My Pregnancy Leg Cramps? Print Now that I'm in my third trimester, I keep getting these painful cramps in my calves. Sometimes they even wake me ...

  15. Ubx regulates differential enlargement and diversification of insect hind legs.

    Directory of Open Access Journals (Sweden)

    Najmus Mahfooz

    2007-09-01

    Full Text Available Differential enlargement of hind (T3 legs represents one of the hallmarks of insect evolution. However, the actual mechanism(s responsible are yet to be determined. To address this issue, we have now studied the molecular basis of T3 leg enlargement in Oncopeltus fasciatus (milkweed bug and Acheta domesticus (house cricket. In Oncopeltus, the T3 tibia displays a moderate increase in size, whereas in Acheta, the T3 femur, tibia, and tarsus are all greatly enlarged. Here, we show that the hox gene Ultrabithorax (Ubx is expressed in the enlarged segments of hind legs. Furthermore, we demonstrate that depletion of Ubx during embryogenesis has a primary effect in T3 legs and causes shortening of leg segments that are enlarged in a wild type. This result shows that Ubx is regulating the differential growth and enlargement of T3 legs in both Oncopeltus and Acheta. The emerging view suggests that Ubx was co-opted for a novel role in regulating leg growth and that the transcriptional modification of its expression may be a universal mechanism for the evolutionary diversification of insect hind legs.

  16. Recurrent Metachronous Acute Compartment Syndrome in the Legs ...

    African Journals Online (AJOL)

    METHODS: A seven-year-old boy presented with four separate episodes of acute compartment syndrome of the legs within three years. The recurrent nature of the illness prompted detail review of the records of the child. RESULTS: There was involvement of each leg twice between the ages of three and seven years ...

  17. In-patient management of leg ulcers | Ohanaka | East African ...

    African Journals Online (AJOL)

    Objective: To review in-patient management of leg ulcers and to compare our experiences with those from other similar centres. Design: A retrospective study. Setting: University of Benin Teaching Hospital, Nigeria. Patients: Forty five patients hospitalisad with leg ulcers. Results: There were 27 male and 18 females (MF 3:2) ...

  18. Common Leg Aliment Of Poultry In Plateau State, Nigeria | Ogbe ...

    African Journals Online (AJOL)

    A study was carried out to investigate the occurrence and causes of leg ailment in poultrythrough questionnaire survey and farm visitation. Post mortem and laboratory examination were also conducted. The results showed that different species of poultry were affected with varous types of leg ailments; out of which local ...

  19. Leg length, sitting height and postmenopausal breast cancer risk

    DEFF Research Database (Denmark)

    Mellemkjær, L; Christensen, J; Frederiksen, K

    2012-01-01

    Tallness has consistently been associated with an increased risk of breast cancer. We investigated the association further by decomposing height into leg length and sitting height.......Tallness has consistently been associated with an increased risk of breast cancer. We investigated the association further by decomposing height into leg length and sitting height....

  20. Leg ulcers: a review of their impact on daily life.

    NARCIS (Netherlands)

    Persoon, A.; Heinen, M.M.; Vleuten, C.J.M. van der; Rooij, M.J.M. de; Kerkhof, P.C.M. van de; Achterberg, T. van

    2004-01-01

    BACKGROUND: Current nursing care for leg ulcer patients often focuses on wound care and providing compression therapy. Nurses perceive leg ulcer patients as 'under-served' with regard to problems patients experience in daily life. An overview of patient problems is a first and essential step in the

  1. The recalcitrant venous leg ulcer - A never ending story?

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan); M.B. Maessen-Visch (Birgitte); S.I. Langendoen; K.P. de Roos; H.A.M. Neumann (Martino)

    2013-01-01

    textabstractIntroduction: In general, four particular causes of recalcitrant venous leg ulcers may be distinguished. These are foot pump insufficiency, chronic venous compartment syndrome and non-re-canalized popliteal vein thrombosis. The fourth cause of recalcitrant venous leg ulcers is

  2. Vibration transmission characteristics of the legs of freely standing honeybees

    DEFF Research Database (Denmark)

    Rohrseitz, Kristin; Kilpinen, Ole

    1997-01-01

    The leg vibrations of honeybees standing on a vibrating substrate were measured with laser Doppler vibrometry, both in freely standing bees and in bees attached to a holder. In both cases, no resonances were found. In the fixed bee preparation, the legs moved with approximately the same amplitude...

  3. A Brief Survey Paper on Multi-Legged Robots

    Directory of Open Access Journals (Sweden)

    Mohammad Behmanesh

    2015-03-01

    Full Text Available This paper presents a brief survey on multi-legged robots and their applications in agriculture such as for harvesting. Multi-legged robots have the benefit of more flexibility and adapt to different rough terrain in a better way. They also have very important applications in fulfilling the dangerous tasks such as mine detecting.

  4. Ubx Regulates Differential Enlargement and Diversification of Insect Hind Legs

    Science.gov (United States)

    Mahfooz, Najmus; Turchyn, Nataliya; Mihajlovic, Michelle; Hrycaj, Steven; Popadić, Aleksandar

    2007-01-01

    Differential enlargement of hind (T3) legs represents one of the hallmarks of insect evolution. However, the actual mechanism(s) responsible are yet to be determined. To address this issue, we have now studied the molecular basis of T3 leg enlargement in Oncopeltus fasciatus (milkweed bug) and Acheta domesticus (house cricket). In Oncopeltus, the T3 tibia displays a moderate increase in size, whereas in Acheta, the T3 femur, tibia, and tarsus are all greatly enlarged. Here, we show that the hox gene Ultrabithorax (Ubx) is expressed in the enlarged segments of hind legs. Furthermore, we demonstrate that depletion of Ubx during embryogenesis has a primary effect in T3 legs and causes shortening of leg segments that are enlarged in a wild type. This result shows that Ubx is regulating the differential growth and enlargement of T3 legs in both Oncopeltus and Acheta. The emerging view suggests that Ubx was co-opted for a novel role in regulating leg growth and that the transcriptional modification of its expression may be a universal mechanism for the evolutionary diversification of insect hind legs. PMID:17848997

  5. Computer-assisted 3D kinematic analysis of all leg joints in walking insects.

    Directory of Open Access Journals (Sweden)

    John A Bender

    Full Text Available High-speed video can provide fine-scaled analysis of animal behavior. However, extracting behavioral data from video sequences is a time-consuming, tedious, subjective task. These issues are exacerbated where accurate behavioral descriptions require analysis of multiple points in three dimensions. We describe a new computer program written to assist a user in simultaneously extracting three-dimensional kinematics of multiple points on each of an insect's six legs. Digital video of a walking cockroach was collected in grayscale at 500 fps from two synchronized, calibrated cameras. We improved the legs' visibility by painting white dots on the joints, similar to techniques used for digitizing human motion. Compared to manual digitization of 26 points on the legs over a single, 8-second bout of walking (or 106,496 individual 3D points, our software achieved approximately 90% of the accuracy with 10% of the labor. Our experimental design reduced the complexity of the tracking problem by tethering the insect and allowing it to walk in place on a lightly oiled glass surface, but in principle, the algorithms implemented are extensible to free walking. Our software is free and open-source, written in the free language Python and including a graphical user interface for configuration and control. We encourage collaborative enhancements to make this tool both better and widely utilized.

  6. The first leg video endoscopic groin lymphadenectomy in vulvar cancer: A case report

    Science.gov (United States)

    Naldini, Angelica; Rossitto, Cristiano; Morciano, Andrea; Panico, Giovanni; Campagna, Giuseppe; Paparella, Pierluigi; Scambia, Giovanni

    2014-01-01

    INTRODUCTION The current management of vulvar cancer depends on the extension of disease, and includes primary tumor resection with safety margin as well as inguinofemoral lymph node staging. We report the case of the first leg videoendoscopic inguinal lymphadenectomy performed in a woman with a squamous cell vulvar carcinoma. PRESENTATION OF CASE A 74 years old female referred to our institution complaining of vulvar mass associated with bleeding and swelling from external genitals, vaginal burning sensation and dysuria for 5 months. A vulvar–vaginal examination under narcosis reported a right major labium lesion of 5 cm with an irregular and ulcerated surface, easily bleeding on palpation, involving anteriorly the clitoral region and with a histological finding of a poorly differentiated squamous cell invasive carcinoma of the vulva ulcerating the surface epithelium. We performed, after adequate informed consent, a radical vulvectomy with a standard right inguinofemoral lymphadenectomy and a contralateral simultaneous video endoscopic inguinal lymphadenectomy-Leg procedure. DISCUSSION Our minimally invasive VEIL-Leg approach, performed for the first time in literature in a woman with vulvar cancer, could reduce the presence of high risk factors represented by surgical incision and by procedure-related complications, including wound infection and breakdown, hematoma, cellulitis and hernia formation. CONCLUSION A multicenter prospective randomized study will be helpful to clarify how this procedure could replace the standard laparotomic approach to inguinal lymphadenectomy in the vulvar cancer treatment and staging. PMID:24973526

  7. Factors Determining the Size of Sealing Clearance in Hydraulic Legs of Powered Supports

    Science.gov (United States)

    Buyalich, Gennady; Buyalich, Konstantin; Byakov, Maxim

    2017-11-01

    The factors that directly influence the formation of a sealing clearance between the piston and the working cylinder in hydraulic legs of powered supports are considered in this article, the size thereof has a direct effect on the tightness of the legs and, as a result, on the safety of work at the production face. A detailed description of these factors is given, which is supported by the dependencies obtained from the results of finite element modeling of various types of legs under various strength and geometric parameters, external load types and locations in the support section. The problems of formation of radial deformations of a working cylinder loaded with working fluid pressure are considered, and their dependence on the level of this pressure and extension. Based on the simulation results, the mechanisms for the formation of additional clearances due to rod and cylinder misalignments are described, and the conditions and causes of the resonant phenomena development are given. The classification of these factors according to the degree of generalization and the functional interaction between each other is proposed.

  8. Computer-assisted 3D kinematic analysis of all leg joints in walking insects.

    Science.gov (United States)

    Bender, John A; Simpson, Elaine M; Ritzmann, Roy E

    2010-10-26

    High-speed video can provide fine-scaled analysis of animal behavior. However, extracting behavioral data from video sequences is a time-consuming, tedious, subjective task. These issues are exacerbated where accurate behavioral descriptions require analysis of multiple points in three dimensions. We describe a new computer program written to assist a user in simultaneously extracting three-dimensional kinematics of multiple points on each of an insect's six legs. Digital video of a walking cockroach was collected in grayscale at 500 fps from two synchronized, calibrated cameras. We improved the legs' visibility by painting white dots on the joints, similar to techniques used for digitizing human motion. Compared to manual digitization of 26 points on the legs over a single, 8-second bout of walking (or 106,496 individual 3D points), our software achieved approximately 90% of the accuracy with 10% of the labor. Our experimental design reduced the complexity of the tracking problem by tethering the insect and allowing it to walk in place on a lightly oiled glass surface, but in principle, the algorithms implemented are extensible to free walking. Our software is free and open-source, written in the free language Python and including a graphical user interface for configuration and control. We encourage collaborative enhancements to make this tool both better and widely utilized.

  9. May 2015 critical care case of the month: an infected leg

    Directory of Open Access Journals (Sweden)

    Till SL

    2015-05-01

    Full Text Available No abstract available. Article truncated at 150 words. History of Present Illness: A 46-year-old transferred due to concern for necrotizing fasciitis. One the day prior to transfer purple discoloration was not noted in the lower portion of the left leg. On the day of transfer the leg became more purple, painful, and swollen. She presented to a pain clinic that advised her to go to an emergency room. The emergency room performed arterial Doppler ultrasound, which was normal and transferred her due to concern of necrotizing fasciitis. Past Medical History, Social History and Family History: She has a past medical history of fibromyalgia. She had an extensive surgical history including an appendectomy, bladder implant, cholecystectomy, dilatation and curettage, esophageal repair, left femoral artery repair due to a motor vehicle accident, partial hysterectomy, left knee surgery, and several left leg operations with grafting. Family history was non-contributory. The patient was single with two children, and smoked 1-2 packs of ...

  10. Diurnal variations in lower leg subcutaneous blood flow rate in patients with chronic venous leg ulcers

    DEFF Research Database (Denmark)

    Sindrup, J H; Kastrup, J; Kristensen, J K

    1991-01-01

    The blood flow rate in subcutaneous adipose tissue was measured on the lower legs of 11 patients with chronic lower-leg venous insufficiency and ulceration and in eight age-matched control subjects for 12-20 h, under ambulatory conditions, using the 133Xe wash-out technique with portable Cadmium...... telluride (CdTe(Cl)) detectors. In both groups, the change from an upright to a supine position at the beginning of the night period elicited an instantaneous increment in the blood flow rate of 30-40% with a decrease in the central and local postural sympathetic vasoconstrictor activity. After...... approximately 1 h of sleep, a considerable increase in blood flow rate was seen in both patient and control groups which persisted for nearly 100 min. In the patient group, the mean increase was 137% compared to a mean increase of 68% in the control group (P less than 0.01). The blood flow then returned...

  11. The response of the MiL-Lx leg fitted with combat boots under impact loading

    CSIR Research Space (South Africa)

    Pandelani, T

    2014-01-01

    Full Text Available methods and concepts. Barbir [7] used the Wayne State University’s linear impactor to show that a standard issue U.S. Army combat boot fitted to HIII leg can decrease peak tibia axial force by as much as 50 percent while increasing the time to peak... weighed 0.615 kg and 0.595 kg, respectively. Although Wang et al. [11] noted that the average velocity and acceleration of a floorplate of a medium sized armoured vehicle may exceed 12 m/s and 100 g’s (1000 m/s2) during an under AVL incident...

  12. Short-interval leg movements during sleep entail greater cardiac activation than periodic leg movements during sleep in restless legs syndrome patients.

    Science.gov (United States)

    Ferri, Raffaele; Rundo, Francesco; Silvani, Alessandro; Zucconi, Marco; Aricò, Debora; Bruni, Oliviero; Lanuzza, Bartolo; Ferini-Strambi, Luigi; Manconi, Mauro

    2017-10-01

    Periodic leg movements during sleep (PLMS) are sequences of ≥4 motor events with intermovement intervals (IMI) of 10-90 s. PLMS are a supportive diagnostic criterion for restless legs syndrome (RLS) and entail cardiac activation, particularly when associated with arousal. RLS patients also over-express short-interval leg movements during sleep (SILMS), which have IMI leg movements. We found that the duration of the R-R interval decrease with SILMS doublets was significantly longer than that with PLMS, whereas the maximal decrease in R-R interval was similar. Scoring SILMS in RLS patients may therefore be relevant from a cardiac autonomic perspective. © 2017 European Sleep Research Society.

  13. Forces in strategy formation

    DEFF Research Database (Denmark)

    Steensen, Elmer Fly; Sanchez, Ron

    2008-01-01

    This chapter proposes that organizational strategy formation should be characterized theoretically as a process that is subject to several interacting forces, rather than represented by separate discrete decisionmodels or theoretic perspectives, as is commonly done in the strategic management...... literature. Based on an extensive review of relevant theory and empirical work in strategic decision-making, organizational change theory, cognitive and social psychology, and strategy processes, seven kinds of ''forces'' - rational, imposed, teleological, learning, political, heuristic, and social...... - are identified as interacting in and having significant influence on the strategy formation process. It is further argued that by applying a holistic ''forces-view'' of the significant and interacting influences on strategy formation, we can better understand the dynamics and challenges in managing the process...

  14. Net joint moments and muscle activation in barbell squats without and with restricted anterior leg rotation.

    Science.gov (United States)

    Chiu, Loren Z F; vonGaza, Gabriella L; Jean, Liane M Y

    2017-01-01

    Muscle utilisation in squat exercise depends on technique. The purpose of this study was to compare net joint moments (NJMs) and muscle activation during squats without and with restricted leg dorsiflexion. Experienced men (n = 5) and women (n = 4) performed full squats at 80% one repetition maximum. 3D motion analysis, force platform and (EMG) data were collected. Restricting anterior leg rotation reduced anterior leg (P = 0.001) and posterior thigh (P  0.05), vastus medialis (P > 0.05) and rectus femoris (P > 0.05) EMG were not different between squat types. Unrestricted squats have higher ankle plantar flexor and knee extensor NJM than previously reported from jumping and landing. However, ankle plantar flexor and knee extensor NJM are lower in restricted squats than previous studies of jumping and landing. The high NJM in unrestricted squat exercise performed through a full range of motion suggests this squat type would be more effective to stimulate adaptations in the lower extremity musculature than restricted squats.

  15. Laboratory on Legs: An Architecture for Adjustable Morphology with Legged Robots

    Science.gov (United States)

    2012-04-01

    evenly throughout the body, all mounted on the waterjet cut frame. Through the use of a USB bus as the common communication method within the robot...according to the overarching “spring assisted actuation” hypothesis just described. The body of Canid is similar to XRL, built from waterjet cut aluminum...on cheap, relatively fast turn-around water jet cut frame components and compliant leg and spine materials offers some useful lessons in effective

  16. Relationship between Leg Mass, Leg Composition and Foot Velocity on Kicking Accuracy in Australian Football

    Directory of Open Access Journals (Sweden)

    Nicolas H. Hart, Jodie L. Cochrane, Tania Spiteri, Sophia Nimphius, Robert U. Newton

    2016-06-01

    Full Text Available Kicking a ball accurately over a desired distance to an intended target is arguably the most important skill to acquire in Australian Football. Therefore, understanding the potential mechanisms which underpin kicking accuracy is warranted. The aim of this study was to examine the relationship between leg mass, leg composition and foot velocity on kicking accuracy in Australian Football. Thirty-one Australian Footballers (n = 31; age: 22.1 ± 2.8 years; height: 1.81 ± 0.07 m; weight: 85.1 ± 13.0 kg; BMI: 25.9 ± 3.2 each performed ten drop punt kicks over twenty metres to a player target. Athletes were separated into accurate (n = 15 and inaccurate (n = 16 kicking groups. Leg mass characteristics were assessed using whole body DXA scans. Foot velocity was determined using a ten-camera optoelectronic, three-dimensional motion capture system. Interactions between leg mass and foot velocity evident within accurate kickers only (r = -0.670 to -0.701. Relative lean mass was positively correlated with kicking accuracy (r = 0.631, while no relationship between foot velocity and kicking accuracy was evident in isolation (r = -0.047 to -0.083. Given the evident importance of lean mass, and its interaction with foot velocity for accurate kickers; future research should explore speed-accuracy, impulse-variability, limb co-ordination and foot-ball interaction constructs in kicking using controlled with-in subject studies to examine the effects of resistance training and skill acquisition programs on the development of kicking accuracy.

  17. Adaptive leg coordination with a biologically inspired neurocontroller

    Science.gov (United States)

    Braught, Grant; Thomopoulos, Stelios C.

    1996-10-01

    Natural selection is responsible for the creation of robust and adaptive control systems. Nature's control systems are created only from primitive building blocks. Using insect neurophysiology as a guide, a neural architecture for leg coordination in a hexapod robot has been developed. Reflex chains and sensory feedback mechanisms from various insects and crustacea form the basis of a pattern generator for intra-leg coordination. The pattern generator contains neural oscillators which learn from sensory feedback to produce stepping patterns. Using sensory feedback as the source of learning information allows the pattern generator to adapt to changes in the leg dynamics due to internal or external causes. A coupling between six of the single leg pattern generators is used to produce the inter-leg coordination necessary to establish stable gaits.

  18. A survey of bio-inspired compliant legged robot designs

    International Nuclear Information System (INIS)

    Zhou Xiaodong; Bi Shusheng

    2012-01-01

    The roles of biological springs in vertebrate animals and their implementations in compliant legged robots offer significant advantages over the rigid legged ones in certain types of scenarios. A large number of robotics institutes have been attempting to work in conjunction with biologists and incorporated these principles into the design of biologically inspired robots. The motivation of this review is to investigate the most published compliant legged robots and categorize them according to the types of compliant elements adopted in their mechanical structures. Based on the typical robots investigated, the trade-off between each category is summarized. In addition, the most significant performances of these robots are compared quantitatively, and multiple available solutions for the future compliant legged robot design are suggested. Finally, the design challenges for compliant legged robots are analysed. This review will provide useful guidance for robotic designers in creating new designs by inheriting the virtues of those successful robots according to the specific tasks. (topical review)

  19. Different forces

    CERN Multimedia

    1982-01-01

    The different forces, together with a pictorial analogy of how the exchange of particles works. The table lists the relative strength of the couplings, the quanta associated with the force fields and the bodies or phenomena in which they have a dominant role.

  20. Effects of gabapentin enacarbil on restless legs syndrome and leg pain in dementia with Lewy bodies.

    Science.gov (United States)

    Fujishiro, Hiroshige

    2014-06-01

    Restless legs syndrome (RLS) is a common neurological disorder. Dementia with Lewy bodies (DLB) is the second most common form of neurodegenerative dementia after Alzheimer's disease. Both RLS and DLB can be effectively treated by dopaminergic medications, suggesting the role of dopamine dysfunction in the pathogenesis of both diseases. Here, I report on a Japanese woman with probable DLB and RLS who was treated with gabapentin enacarbil, a non-dopaminergic agent. Because a dopamine agonist, a first-line therapy for moderate to severe RLS, caused the occurrence of metamorphopsia, an alternative treatment of gabapentin enacarbil was used; this treatment improved the patient's RLS without worsening her psychiatric symptoms. An alternative treatment is desirable for DLB patients with RLS because they often experience intolerable side-effects with a dopamine agonist, especially visual hallucinations. Administering gabapentin enacarbil also improved the continuous leg pain that occurred in conjunction with the development of RLS. Although the neurobiological mechanism in the development of pain remains unclear, a range of non-dopaminergic structures likely mediated pain processing in DLB in the present case based on neuropharmacological results. This is the first report reporting the effects of gabapentin enacarbil for RLS and leg pain in a DLB patient with psychiatric symptoms. © 2014 The Author. Psychogeriatrics © 2014 Japanese Psychogeriatric Society.

  1. LEGS AND TRUNK MUSCLE HYPERTROPHY FOLLOWING WALK TRAINING WITH RESTRICTED LEG MUSCLE BLOOD FLOW

    Directory of Open Access Journals (Sweden)

    Mikako Sakamaki

    2011-06-01

    Full Text Available We examined the effect of walk training combined with blood flow restriction (BFR on the size of blood flow-restricted distal muscles, as well as, on the size of non-restricted muscles in the proximal limb and trunk. Nine men performed walk training with BFR and 8 men performed walk training alone. Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min, with a 1-min rest between bouts. After walk training with BFR, MRI-measured upper (3.8%, P < 0.05 and lower leg (3.2%, P < 0. 05 muscle volume increased significantly, whereas the muscle volume of the gluteus maximus (-0.6% and iliopsoas (1.8% and the muscle CSA of the lumber L4-L5 (-1.0 did not change. There was no significant change in muscle volume in the walk training alone. Our results suggest that the combination of leg muscle blood flow restriction with slow walk training elicits hypertrophy only in the distal blood flow restricted leg muscles. Exercise intensity may be too low during BFR walk training to increase muscle mass in the non- blood flow restricted muscles (gluteus maximus and other trunk muscles.

  2. Protection against high intravascular pressure in giraffe legs.

    Science.gov (United States)

    Petersen, Karin K; Hørlyck, Arne; Ostergaard, Kristine H; Andresen, Joergen; Broegger, Torbjoern; Skovgaard, Nini; Telinius, Niklas; Laher, Ismael; Bertelsen, Mads F; Grøndahl, Carsten; Smerup, Morten; Secher, Niels H; Brøndum, Emil; Hasenkam, John M; Wang, Tobias; Baandrup, Ulrik; Aalkjaer, Christian

    2013-11-01

    The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along the artery. Histology of the isolated median artery confirmed dense sympathetic innervation at the narrowing. Structure and contractility of small arteries from muscular beds in the leg and neck were compared. The arteries from the legs demonstrated an increased media thickness-to-lumen diameter ratio, increased media volume, and increased numbers of smooth muscle cells per segment length and furthermore, they contracted more strongly than arteries from the neck (500 ± 49 vs. 318 ± 43 mmHg; n = 6 legs and neck, respectively). Finally, the transient increase in interstitial fluid pressure following injection of saline was 5.5 ± 1.7 times larger (n = 8) in the leg than in the neck. We conclude that 1) tissue compliance in the legs is low; 2) large arteries of the legs function as resistance arteries; and 3) structural adaptation of small muscle arteries allows them to develop an extraordinary tension. All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure.

  3. Sticking like sticky tape: tree frogs use friction forces to enhance attachment on overhanging surfaces.

    Science.gov (United States)

    Endlein, Thomas; Ji, Aihong; Samuel, Diana; Yao, Ning; Wang, Zhongyuan; Barnes, W Jon P; Federle, Walter; Kappl, Michael; Dai, Zhendong

    2013-03-06

    To live and clamber about in an arboreal habitat, tree frogs have evolved adhesive pads on their toes. In addition, they often have long and slender legs to facilitate not only long jumps, but also to bridge gaps between leaves when climbing. Both adhesive pads and long limbs are used in conjunction, as we will show in this study. Previous research has shown that tree frogs change from a crouched posture (where the limbs are close to the body) to a sprawled posture with extended limbs when clinging on to steeper inclines such as vertical or overhanging slopes. We investigated this change in posture in White's tree frogs (Litoria caerulea) by challenging the frogs to cling onto a tiltable platform. The platform consisted of an array of 24 three-dimensional force transducers, which allowed us to measure the ground reaction forces of the frogs during a tilt. Starting from a crouched resting position, the normal forces on the forelimbs changed sign and became increasingly negative with increasing slope angle of the platform. At about 106° ± 12°, tilt of the platform the frogs reacted by extending one or two of their limbs outwards. At a steeper angle (131° ± 11°), the frogs spread out all their limbs sideways, with the hindlimbs stretched out to their maximum reach. Although the extension was strongest in the lateral direction, limbs were significantly extended in the fore-aft direction as well. With the extension of the limbs, the lateral forces increased relative to the normal forces. The large contribution of the in-plane forces helped to keep the angle between the force vector and the platform small. The Kendall theory for the peeling of adhesive tape predicts that smaller peel angles lead to higher attachment forces. We compare our data with the predictions of the Kendall model and discuss possible implications of the sliding of the pads on the surface. The forces were indeed much larger for smaller angles and thus can be explained by peeling theory.

  4. Single-leg squats can predict leg alignment in dancers performing ballet movements in “turnout”

    Directory of Open Access Journals (Sweden)

    Hopper LS

    2016-11-01

    Full Text Available Luke S Hopper,1 Nahoko Sato,2 Andries L Weidemann1 1Western Australian Academy of Performing Arts, Edith Cowan University, Mt Lawley, WA, Australia; 2Department of Physical Therapy, Nagoya Gakuin University, Seto, Japan Abstract: The physical assessments used in dance injury surveillance programs are often adapted from the sports and exercise domain. Bespoke physical assessments may be required for dance, particularly when ballet movements involve “turning out” or external rotation of the legs beyond that typically used in sports. This study evaluated the ability of the traditional single-leg squat to predict the leg alignment of dancers performing ballet movements with turnout. Three-dimensional kinematic data of dancers performing the single-leg squat and five ballet movements were recorded and analyzed. Reduction of the three-dimensional data into a one-dimensional variable incorporating the ankle, knee, and hip joint center positions provided the strongest predictive model between the single-leg squat and the ballet movements. The single-leg squat can predict leg alignment in dancers performing ballet movements, even in “turned out” postures. Clinicians should pay careful attention to observational positioning and rating criteria when assessing dancers performing the single-leg squat. Keywords: injury, motion capture, clinical assessment

  5. Saphenofemoral ligation as a safe and effective alternative for the treatment of chronic venous leg ulcer

    International Nuclear Information System (INIS)

    El-Hafez, Emad A.; Seleem, Mohamed I.

    2004-01-01

    To evaluate the effectiveness and safety of isolated saphenofemoral junction ligation for the treatment of chronic venous leg ulcer in comparison to traditional stripping procedure. 36 patients (28 men and 8 women) with mean age of 42.3+-8.7, presented with a venous leg ulcer. After taking the full history, they underwent examination for presence of edema, cellulitis or local ulcer infection. The site and size of ulceration were recorded and ankle-brachial pressure index (ABPI) was measured, Venous valvular incompetence was assessed using Valsalva testand calf compression. Patients were divided into 2 groups. Group I, (n=10) assigned for long saphenous stripping, while group II (n=26) assigned for saphenofemoral ligationan and divided combined with ligation of major tributaries under local infiltration anesthesia. Mean operative time, postoperative complications and hospital stay were recorded. The study was carried out in Benha University Hospital, Egypt and Armed Forces Hospital, Southern Region, Khamis Mushayt, Sadi Arabia between January 2000 and December 2001. The mean operative time and the hospital stay were significantly (p<0.05) reduced in group II compared to group I. The postoperative complications were signficantly (x=7.5, p<0.05) reduced in group II. Ulcer healing started after 3 months in group II and six months in group I, but by 12 month, group II had significant (x=6.7, p<0.05) number of healed ulcers (n=22, 84.6%), compared to group I (n=7, 70%). The isolated ligation of of saphenofemoral junction is a minimally invasive, safe and effective modality for treatment of chronic leg ulcer, and being easily performed under local anesthesia and considerd to be a satisfactory procedure for treatment of leg ulcer in patients who are unfit for general anesthesia. (author)

  6. Artificial Leg Design and Control Research of a Biped Robot with Heterogeneous Legs Based on PID Control Algorithm

    Directory of Open Access Journals (Sweden)

    Hualong Xie

    2015-04-01

    Full Text Available A biped robot with heterogeneous legs (BRHL is proposed to provide an ideal test-bed for intelligent bionic legs (IBL. To make artificial leg gait better suited to a human, a four-bar mechanism is used as its knee joint, and a pneumatic artificial muscle (PAM is used as its driving source. The static mathematical model of PAM is established and the mechanical model of a single degree of freedom of a knee joint driven by PAM is analyzed. A control simulation of an artificial leg based on PID control algorithm is carried out and the simulation results indicate that the artificial leg can simulate precisely a normal human walking gait.

  7. Reliability of performance measurements derived from ground reaction force data during countermovement jump and the influence of sampling frequency.

    Science.gov (United States)

    Hori, Naruhiro; Newton, Robert U; Kawamori, Naoki; McGuigan, Michael R; Kraemer, William J; Nosaka, Kazunori

    2009-05-01

    Force platforms are used extensively to measure force and power output during countermovement jump (CMJ). The purpose of this study was to examine measurement reliability and validity of commonly used performance measurements derived from ground reaction force (GRF)-time data during CMJ and the influence of sampling at different frequencies. Twenty-four men performed 2 trials of CMJ on a force platform, and GRF-time data were sampled at a rate of 500 Hz. Data obtained at 500 Hz were considered as the reference, and then data were resampled at 400, 250, 200, 100, 50, and 25 Hz, using interpolation. Commonly used power, force, and velocity performance measures were obtained from GRF-time data. Reliability was assessed by intraclass correlation coefficient (ICC) and coefficient of variation (CV) between the 2 trials within the session. Peak power, peak force, and peak velocity were highly reliable across all sampling frequencies (ICC = 0.92-0.98, CV = 1.3-4.1). Percentage differences from 500-Hz reference values ranged from -0.85 to 0.20% at 400 Hz, -1.88 to 0.89% at 250 Hz, -1.80 to 1.31% at 200 Hz, -3.63 to 3.34% at 100 Hz, -11.37 to 6.51% at 50 Hz, and -13.17 to 9.03% at 25 Hz. In conclusion, peak power, force, and velocity measurements derived from GRF to assess leg extensor capabilities are reliable within a test session except for peak rate of force development and time to peak power. With regard to sampling frequency, scientists and practitioners may consider sampling as low as 200 Hz, depending on the purpose of measurement, because the percentage difference is not markedly enlarged until the frequency is 100 Hz or lower.

  8. A miniature surface tension-driven robot using spatially elliptical moving legs to mimic a water strider's locomotion.

    Science.gov (United States)

    Yan, J H; Zhang, X B; Zhao, J; Liu, G F; Cai, H G; Pan, Q M

    2015-08-04

    The highly agile and efficient water-surface locomotion of the water strider has stimulated substantial interest in biomimetic research. In this paper, we propose a new miniature surface tension-driven robot inspired by the water strider. A key feature of this robot is that its actuating leg possesses an ellipse-like spatial trajectory similar to that of a water strider by using a cam-link mechanism. Simplified models are presented to discuss the leg-water interactions as well as critical conditions for a leg penetrating the water surface, and simulations are performed on the robot's dynamic properties. The final fabricated robot weighs about 3.9 g, and can freely and stably walk on water at different gaits. The maximum forward and turning speeds of the robot are measured as 16 cm s(-1) and 23°/s, respectively. Furthermore, a similarity analysis with Bond number and Weber number demonstrates that the locomotion of this robot is quite analogous to that of a real water strider: the surface tension force dominates the lifting force and plays a major role in the propulsion force. This miniature surface tension-driven robot might have potential applications in many areas such as water quality monitoring and aquatic search and rescue.

  9. Differential diagnosis of unpleasant sensations in the legs: prevalence of restless legs syndrome in a primary care population.

    Science.gov (United States)

    Möller, Caroline; Wetter, Thomas C; Köster, Jürgen; Stiasny-Kolster, Karin

    2010-02-01

    Restless legs syndrome (RLS) is a common neurological condition. We investigated the prevalence of RLS in patients suffering from unpleasant sensations in the legs. We included 16,543 patients consulting one of 312 primary care practices in Germany on November 8, 2007. All patients filled out a self-assessment questionnaire. Patients who reported suffering from unpleasant sensations in the legs were then assessed by the physician. Main outcome measures were the overall prevalence of unpleasant sensations in the legs and the prevalence of RLS; the most common differential diagnoses in the subpopulation suffered from unpleasant leg sensations. Out of all participating patients 7704 (46.6%) suffered from unpleasant sensations in the legs and 1758 (10.6%) were diagnosed with RLS according to the four essential clinical criteria. Among patients with unpleasant leg sensations, the prevalence of RLS was considerably higher (22.7%) than in the total population. The most common differential diagnoses were osteoarthritis (21.5%), disc lesion (19.2%), varicose veins (18.8%) and muscle cramps (14.6%). Of the patients with RLS 53.4% had already consulted their physician about their leg problems in the past. Still, only 20.1% of the RLS patients had received the correct diagnosis. Comorbidity rates were significantly increased in RLS patients compared to patients suffering from leg symptoms of other origin. This study showed a high prevalence of RLS in primary care patients with unpleasant sensations in the legs. Thus, in patients presenting with these symptoms the diagnosis of RLS should routinely be considered. 2009 Elsevier B.V. All rights reserved.

  10. Type extension trees

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2006-01-01

    We introduce type extension trees as a formal representation language for complex combinatorial features of relational data. Based on a very simple syntax this language provides a unified framework for expressing features as diverse as embedded subgraphs on the one hand, and marginal counts...... of attribute values on the other. We show by various examples how many existing relational data mining techniques can be expressed as the problem of constructing a type extension tree and a discriminant function....

  11. Spacetime extensions Pt. 1

    International Nuclear Information System (INIS)

    Racz, I.

    1991-09-01

    The problem of the existence of local extensions of spacetime is considered. It is shown that for a spacetime including an incomplete inextendible non-coiling causal geodesic curve there exists a particular C k (resp. C k- ) local extension provided that the curvature and its covariant derivatives are well behaved up to order k + 1 (resp. k) along a family of causal geodetics (around the chosen one). (R.P.) 15 refs

  12. Restless legs syndrome in patients on dialysis

    International Nuclear Information System (INIS)

    AlJahdali, Hamdan H; AlQadhi, Waleed A; Khogeer, Haithm A; AlHejaili, Fayez F; Al Sayyari, Abdullah A; AlGhamdi, Saeed M

    2009-01-01

    Restless legs syndrome (RLS) is an extremely distressing problem experienced by patients on dialysis; the prevalence appears to be greater than in the general population, with a wide variation from 6.6% to 80%. The diagnosis of RLS is a clinical one, and its definition has been clarified and standardized by internationally recognized diagnostic criteria, published in 1995 by the International Restless Legs Syndrome Study Group (IRLSSG). This study was designed to find out the prevalence of RLS in Saudi patients with end-stage renal disease (ESRD) on maintenance dialysis. This is a cross sectional study carried out between May and Sept 2007 at two centers, King Abdulaziz Medical City-King Fahad National Guard Hospital (KAMC-KFNGH), Riyadh and King Faisal Specialist Hospital and Research Centre (KFHRC), Jeddah, Saudi Arabia. Data were gathered on 227 Saudi patients on chronic maintenance hemodialysis or chronic peritoneal dialysis. The prevalence of RLS was measured using IRLSSG's RLS Questionnaire (RLSQ). Potential risk factors for RLS including other sleep disorders, underlying cause of chronic renal failure, duration on dialysis, dialysis shift, biochemical tests and demographic data were also evaluated. The overall prevalence of RLS was 50.22% including 53.7% males and 46.3% females. Their mean age was 55.7 + - 17.2 years and mean duration on dialysis 40.4 + - 37.8 months. Significant predictors of RLS were history of diabetes mellitus (DM), coffee intake, afternoon dialysis, gender and type of dialysis (P= 0.03, 0.01, < 0.001, 0.05 and 0.009 respectively). Patients with RLS were found to be at increased risk of having insomnia and excessive daytime sleepiness (EDS) (P= < 0.001 and 0.001, respectively). Our study suggests that RLS is a very common problem in dialysis population and was significantly associated with other sleep disorders, particularly insomnia, and EDS. Optimal care of dialysis patient should include particular attention to the diagnosis and

  13. Restless legs syndrome in patients on dialysis

    Directory of Open Access Journals (Sweden)

    Al-Jahdali Hamdan

    2009-01-01

    Full Text Available Restless legs syndrome (RLS is an extremely distressing problem experienced by patients on dialysis; the prevalence appears to be greater than in the general population, with a wide variation from 6.6% to 80%. The diagnosis of RLS is a clinical one, and its definition has been clarified and standardized by internationally recognized diagnostic criteria, published in 1995 by the International Restless Legs Syndrome Study Group (IRLSSG. This study was designed to find out the prevalence of RLS in Saudi patients with end-stage renal disease (ESRD on maintenance dialysis. This is a cross sectional study carried out between May and Sept 2007 at two centers, King Abdulaziz Medical City-King Fahad National Guard Hospital (KAMC-KFNGH, Riyadh and King Faisal Specialist Hospital and Research Centre (KFHRC, Jeddah, Saudi Arabia. Data were gathered on 227 Saudi patients on chronic maintenance hemodialysis or chronic peritoneal dialysis. The prevalence of RLS was measured using IRLSSG′s RLS Questionnaire (RLSQ. Potential risk factors for RLS including other sleep disorders, underlying cause of chronic renal failure, duration on dialysis, dialysis shift, biochemical tests and demographic data were also evaluated. The overall prevalence of RLS was 50.22% including 53.7% males and 46.3% females. Their mean age was 55.7 ± 17.2 years and mean duration on dialysis 40.4 ± 37.8 months. Significant predictors of RLS were history of diabetes mellitus (DM, coffee intake, afternoon dialysis, gender and type of dialysis (P= 0.03, 0.01, < 0.001, 0.05 and 0.009 respectively. Patients with RLS were found to be at increased risk of having insomnia and excessive daytime sleepiness (EDS (P= < 0.001 and 0.001, respectively. Our study suggests that RLS is a very common problem in dialysis population and was significantly associated with other sleep disorders, particularly insomnia, and EDS. Optimal care of dialysis patient should include particular attention to the diagnosis

  14. STRETCHING EXERCISES - EFFECT ON PASSIVE EXTENSIBILITY AND STIFFNESS IN SHORT HAMSTRINGS OF HEALTHY-SUBJECTS

    NARCIS (Netherlands)

    HALBERTSMA, JPK; GOEKEN, LNH

    Passive muscle stretch tests are common practice in physical therapy and rehabilitation medicine. However, the effects of stretching exercises are not well known. With an instrumental straight-leg-raising set-up the extensibility, stiffness, and electromyographic activity of the hamstring muscles

  15. The MARTINI coarse-grained force field : Extension to proteins

    NARCIS (Netherlands)

    Monticelli, Luca; Kandasamy, Senthil K.; Periole, Xavier; Larson, Ronald G.; Tieleman, D. Peter; Marrink, Siewert-Jan

    Many biologically interesting phenomena occur on a time scale that is too long to be studied by atomistic simulations. These phenomena include the dynamics of large proteins and self-assembly of biological materials. Coarse-grained (CG) molecular modeling allows computer simulations to be run on

  16. Consensus clinical practice guidelines for the diagnosis and treatment of restless legs syndrome/Willis-Ekbom disease during pregnancy and lactation.

    Science.gov (United States)

    Picchietti, Daniel L; Hensley, Jennifer G; Bainbridge, Jacquelyn L; Lee, Kathryn A; Manconi, Mauro; McGregor, James A; Silver, Robert M; Trenkwalder, Claudia; Walters, Arthur S

    2015-08-01

    Restless legs syndrome (RLS)/Willis-Ekbom disease (WED) is common during pregnancy, affecting approximately one in five pregnant women in Western countries. Many report moderate or severe symptoms and negative impact on sleep. There is very little information in the medical literature for practitioners on the management of this condition during pregnancy. Accordingly, a task force was chosen by the International RLS Study Group (IRLSSG) to develop guidelines for the diagnosis and treatment of RLS/WED during pregnancy and lactation. A committee of nine experts in RLS/WED and/or obstetrics developed a set of 12 consensus questions, conducted a literature search, and extensively discussed potential guidelines. Recommendations were approved by the IRLSSG executive committee, reviewed by IRLSSG membership, and approved by the WED Foundation Medical Advisory Board. These guidelines address diagnosis, differential diagnosis, clinical course, and severity assessment of RLS/WED during pregnancy and lactation. Nonpharmacologic approaches, including reassurance, exercise and avoidance of exacerbating factors, are outlined. A rationale for iron supplementation is presented. Medications for RLS/WED are risk/benefit rated for use during pregnancy and lactation. A few are rated "may be considered" when RLS/WED is refractory to more conservative approaches. An algorithm summarizes the recommendations. These guidelines are intended to improve clinical practice and promote further research. Copyright © 2014. Published by Elsevier Ltd.

  17. Nurses' knowledge about venous leg ulcer care: a literature review.

    Science.gov (United States)

    Ylönen, M; Stolt, M; Leino-Kilpi, H; Suhonen, R

    2014-06-01

    There is an increasing prevalence of venous leg ulcers coinciding with increasing older people populations. They are therefore important health problems, which restrict daily activities and incur high costs. Efficient and comprehensive nursing care for people with venous leg ulcers requires knowledge of causes, presentations and characteristics, the effects that venous leg ulcers have on individuals and nursing care with evidence-based treatment. To identify the gaps between nurses' demonstrated knowledge of venous leg ulcers and the related nursing care treatment with evidence-based nursing care. A computerized search using MEDLINE, CINAHL the COCHRANE LIBRARY was conducted. The initial search yielded 174 citations from which 16 relevant articles were included in this review. Four themes in venous leg ulcer nursing care emerged demonstrating nurses' knowledge gaps: assessment, physiology and the healing process, nursing care and dressings, and compression treatment. This review suggests that there is a lack of knowledge related to venous leg ulcer physiology, the healing process and how this influences care and treatment. Nurses may not be using the evidence base sufficiently well to support ulcer healing and patient well-being. There is a need for a positive work culture development and ongoing educational programmes aimed at improving nurses' knowledge of venous leg ulcer treatment and care, which address the themes within the results of this review. © 2014 International Council of Nurses.

  18. Comparison of Alternative Gaits for Multiped Robots with Severed Legs

    Directory of Open Access Journals (Sweden)

    Tse-Shuen Shih

    2012-10-01

    Full Text Available Multiped robots have become the focus of heated discussion lately, especially in applications involving rescue or military missions and underwater or extra-terrestrial explorations. The surroundings concerned are harsh and hazardous terrains, and predictably the malfunction rate is high. What if a leg is irreparably damaged? The original gait can no longer be used and an alternative gait must be taken for the robot to continue its mission. This paper studies and enumerates preferred alternative gaits for six- and eight-legged robots under a proposed severed leg scheme. A leg is assumed to be completely detachable when a failure occurs. Based on a new criterion called the progressive efficiency (PE, defined via the enhanced gait charts, along with other criteria like the stride length and the longitudinal stability, alternative gaits are evaluated. The tables of recommended gaits in this paper are useful for robots when a leg failure is foreseen. These tables not only provide a guideline as to what alternative gait to use, they also give insight into how important a certain leg is. A comparison between the severed leg scheme and the existing locked-joint strategy is also included.

  19. Laterality of the legs in young female soccer players

    Directory of Open Access Journals (Sweden)

    Antosiak-Cyrak Katarzyna Z.

    2015-12-01

    Full Text Available Purpose. The aim of the present study was assessment of laterality of the legs of young female soccer players and their non-training counterparts. Methods. The study sample comprised 9 female soccer players and 19 non-training girls. They underwent three measurement sessions, one every six months. The applied tests included kinesthetic differentiation, rate of local movements, static balance, single-leg hop, rate of global movements, strength and speed, and functional asymmetry of the legs tests. Results. The soccer players were better than the controls in their performance of the rate of local movements, rate of global movements, kinesthetic differentiation, single-leg 15m timed hop and static balance tests. Smaller differences between the results of the left and the right legs in soccer players, than in non-training girls, were noted in the rate of local movements, rate of global movements and kinesthetic differentiation tests. In the static balance test, the differences were greater in the group of soccer players. Conclusions. Lateralization of the lower limbs is a highly complex characteristic with a different variability in athletes than in nontraining individuals. The results of the present study also point to the specialization of soccer players’ left legs in body balance and single-leg hop tests.

  20. A comparison of acute effects between Kinesio tape and electrical muscle elongation in hamstring extensibility.

    Science.gov (United States)

    Espejo-Antúnez, L; López-Miñarro, P A; Garrido-Ardila, E M; Castillo-Lozano, R; Domínguez-Vera, P; Maya-Martín, J; Albornoz-Cabello, M

    2015-01-01

    To improve hamstring extensibility some methods have been analyzed and compared for determining their acute and chronic effectiveness. To compare the immediate effect of electrical muscle elongation (EME) versus Kinesio tape (KT) in hamstring muscle extensibility. One hundred and twenty adult amateur athletes with hamstring shortness (straight leg raise test angle Kinesio tape are effective techniques in the short-term in amateur athletes with decreased hamstring extensibility. The higher increase of hamstring extensibility, with a better clinical effect was achieved with the application of electrical muscle elongation. However, no significant differences were found when comparing the effectiveness of both techniques.

  1. Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics

    Directory of Open Access Journals (Sweden)

    Lockie Robert G.

    2015-12-01

    Full Text Available This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time, and leg muscle performance (power, stiffness, strength. Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ, a fivebound test (5BT, and the reactive strength index (RSI defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson’s correlations and stepwise regression (p ≤ 0.05 determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54. The 5BT (5-10 and 0-10 m intervals and RSI (5-10 m interval also related to velocity (r = 0.37-0.47. Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51, and a longer 0-10 m step length (r = 0.38. Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r2 = 0.14-0.29 tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.

  2. Single leg stance control in individuals with symptomatic gluteal tendinopathy.

    Science.gov (United States)

    Allison, Kim; Bennell, Kim L; Grimaldi, Alison; Vicenzino, Bill; Wrigley, Tim V; Hodges, Paul W

    2016-09-01

    Lateral hip pain during single leg loading, and hip abductor muscle weakness, are associated with gluteal tendinopathy, but it has not been shown how or whether kinematics in single leg stance differ in those with gluteal tendinopathy. To compare kinematics in preparation for, and during, single leg stance between individuals with and without gluteal tendinopathy, and the effect of hip abductor muscle strength on kinematics. Twenty individuals with gluteal tendinopathy and 20 age-matched pain-free controls underwent three-dimensional kinematic analysis of single leg stance and maximum isometric hip abductor strength testing. Maximum values of hip adduction, pelvic obliquity (contralateral pelvis rise/drop), lateral pelvic translation (ipsilateral/contralateral shift) and ipsilateral trunk lean during preparation for leg lift and average values in steady single leg stance, were compared between groups using an analysis of covariance, with and without anthropometric characteristics and strength as covariates. Individuals with gluteal tendinopathy demonstrated greater hip adduction (standardized mean difference (SMD)=0.70, P=0.04) and ipsilateral pelvic shift (SMD=1.1, P=0.002) in preparation for leg lift, and greater hip adduction (SMD=1.2, P=0.002) and less contralateral pelvic rise (SMD=0.86, P=0.02) in steady single leg stance than controls. When including strength as a covariate, only between-group differences in lateral pelvic shift persisted (SMD=1.7, P=0.01). Individuals with gluteal tendinopathy use different frontal plane kinematics of the hip and pelvis during single leg stance than pain-free controls. This finding is not influenced by pelvic dimension or the potentially modifiable factor of body mass index, but is by hip abductor muscle weakness. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics.

    Science.gov (United States)

    Lockie, Robert G; Jalilvand, Farzad; Callaghan, Samuel J; Jeffriess, Matthew D; Murphy, Aron J

    2015-12-22

    This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a five-bound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson's correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54). The 5BT (5-10 and 0-10 m intervals) and RSI (5-10 m interval) also related to velocity (r = 0.37-0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51), and a longer 0-10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r(2) = 0.14-0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.

  4. Forced Sex among Married or Steady Partners in Uganda

    African Journals Online (AJOL)

    Erah

    Researchers were trained to ask probing questions and use active listening techniques because the interviews .... Ordinarily a married woman is not supposed to ask for sex directly: I am not a prostitute...he would think I ... legs: I tell my wife that sexual intercourse is a major contract I have with her. I force my wife to have sex ...

  5. Pramipexole alters thermoregulation in restless legs syndrome.

    Science.gov (United States)

    Salminen, Aaro V; Rimpilä, Ville; Polo, Olli

    2014-12-15

    Previous studies have associated restless legs syndrome (RLS) with peripheral hypoxia and impaired thermoregulation in the lower extremities. We performed long-term monitoring of skin temperatures in order to investigate whether these findings could be explained by reduced blood flow to the peripheral tissues. 96-hour continuous measurements of skin temperature were performed both in the distal and proximal parts of the body of 15 patients with RLS and 14 healthy controls. During the recording, the patients participated in suggested immobilization tests both with and without pramipexole medication. We found no baseline differences in distal or proximal skin temperature between patients and controls in daytime or during immobilization. However, pramipexole significantly increased distal skin temperature in the patient group during immobilization (31.1°C vs. 32.9°C, p thermoregulation and the previous studies might have been biased by medication. Dopaminergic medication is a major confounding factor when assessing peripheral phenomena in RLS and should be controlled for in the future studies. © 2014 American Academy of Sleep Medicine.

  6. Restless legs syndrome associated with major diseases

    Science.gov (United States)

    Allen, Richard; Högl, Birgit; Paulus, Walter

    2016-01-01

    Recent publications on both the genetics and environmental factors of restless legs syndrome (RLS) defined as a clinical disorder suggest that overlapping genetic risk factors may play a role in primary (idiopathic) and secondary (symptomatic) RLS. Following a systematic literature search of RLS associated with comorbidities, we identified an increased prevalence of RLS only in iron deficiency and kidney disease. In cardiovascular disease, arterial hypertension, diabetes, migraine, and Parkinson disease, the methodology of studies was poor, but an association might be possible. There is insufficient evidence for conditions such as anemia (without iron deficiency), chronic obstructive pulmonary disease, multiple sclerosis, headache, stroke, narcolepsy, and ataxias. Based on possible gene–microenvironmental interaction, the classifications primary and secondary RLS may suggest an inappropriate causal relation. We recognize that in some conditions, treatment of the underlying disease should be achieved as far as possible to reduce or eliminate RLS symptoms. RLS might be seen as a continuous spectrum with a major genetic contribution at one end and a major environmental or comorbid disease contribution at the other. PMID:26944272

  7. Restless legs syndrome and pregnancy: A review

    Science.gov (United States)

    Srivanitchapoom, Prachaya; Pandey, Sanjay; Hallett, Mark

    2014-01-01

    Restless legs syndrome (RLS) is a common sensorimotor neurological disorder that is diagnosed according to the revised criteria of the International RLS Study Group (IRLSSG). The pathophysiology of RLS is still unknown and its prevalence is influenced by ethnicity, age, and gender. RLS is divided into two types by etiology: primary or idiopathic and secondary. Primary RLS is strongly influenced by a genetic component while secondary RLS is caused by other associated conditions such as end-stage renal disease or peripheral neuropathy. Another common condition associated with RLS is pregnancy. The prevalence of RLS during pregnancy is two to three times higher than in the normal population and is influenced by the trimester and the number of parity. The main mechanisms that may contribute to the pathophysiology of RLS during pregnancy are hormonal changes and iron and folate status. Standard medications for treating RLS during pregnancy are not established. Most medications have been used according to the evidence from non-pregnant patients. Therefore, consideration of the medical treatment for treating RLS during pregnancy should be balanced between the benefit of relieving the symptoms and maternal and fetal risk. In general, the prognosis of RLS during pregnancy is good and symptoms are usually relieved after delivery. PMID:24768121

  8. Clinical correlates of the restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Luis Fabiano Marin

    2012-07-01

    Full Text Available OBJECTIVE: To determine the clinical correlates of the restless legs syndrome (RLS in a Brazilian sleep disorders center. METHODS: We retrospectively studied 118 patients with RLS from January, 2004, to December, 2010. The analyzed variables were: age at disease onset, gender, race, years of school instruction, primary and secondary RLS, and treatment options. RESULTS: Among the studied patients, 83.9% were women with a female/male sex ratio of 5:1. Mean age of the patients at symptom onset ± standard deviation was 41.7±17.9 years-old. The primary RLS was found in 85% of patients. The other 15% remainders consisted of secondary forms, and they were associated with neuropathy, iron deficiency anemia, end-stage renal disease, or Parkinson's disease. Drug therapy for RLS was introduced in 67% of patients. CONCLUSIONS: Most patients presented primary RLS with an early disease onset. Further epidemiological studies are welcomed to provide better information on secondary RLS in Brazil.

  9. Analytical Study of Active Prosthetic Legs

    Science.gov (United States)

    Ono, Kyosuke; Katsumata, Mie

    Walking with prosthesis has not been well analyzed mathematically and it seems that the design of powered prosthesis has been done empirically so far. This paper presents a dynamic simulation of a normal human walking and walking with an active prosthesis. We also studied the two controlling methods of a powered thigh prosthesis based on multi-body simulation of human walking. First we measured the normal human walking gait, then, we showed that a 3-DOF human walking model can walk on level ground by applying tracking control to the measured walking gait within a certain range of tuned walking period. Next, we applied the tracking control and self-excited control to the powered thigh prosthesis and compared the robustness and efficiency of the two control methods by numerical simulation. As a result, we found that the self-excited control can significantly decrease the hip joint torque and specific cost to 1/3 compared with the tracking control. Moreover, the self-excited control is superior to the tracking control because tuning for the walking period is not needed for the active prosthetic leg.

  10. [Prophylaxis of Recurrent Venous Leg Ulcer].

    Science.gov (United States)

    Kroeger, K; Storck, M; Kujath, P; Rabe, E; Dissemond, J

    2017-06-01

    Venous leg ulcer (VLU) counts among the most common chronic wounds in Europe. Treatment is lengthy, cumbersome and costly, and there is a high rate of recurrence. This review shows the measures that should be offered to every patient with healed VLU to permanently prevent recurrence. To prevent VLU in case of varicose veins, the progression of chronic venous insufficiency (CVI) has to be stopped. There is convincing evidence that the effective treatment of varicose veins reduces the recurrence rate in patients with VLU. In patients with post-thrombotic syndrome (PTS), further thrombosis should be prevented through targeted prophylaxis of new thromboembolic events. The benefit of endovascular revascularization on the VLU recurrence rate in patients with post-thrombotic damage in the pelvic veins has not been proven in clinical studies. On the other hand, it has been clearly demonstrated in several studies that compression therapy is the basic procedure for the prevention of recurrent VLU in patients with varicose veins or PTS, regardless of whether other measures have been implemented or not. Good adherence in patients with compression therapy is more important than choosing the highest possible compression class. Future efforts for patients with VLU must aim to provide therapists with tools and treatment strategies to guide their patients and to increase patients' acceptance and understanding of the importance of self-management, in particular regarding compression therapy for the prevention of recurrent VLU. Georg Thieme Verlag KG Stuttgart · New York.

  11. Primary headaches in restless legs syndrome patients

    Directory of Open Access Journals (Sweden)

    Ravi Gupta

    2012-01-01

    Full Text Available Earlier studies conducted among migraineurs have shown an association between migraine and restless legs syndrome (RLS. We chose RLS patients and looked for migraine to exclude sample bias. Materials and Methods: 99 consecutive subjects of idiopathic RLS were recruited from the sleep clinic during four months period. Physician diagnosis of headache and depressive disorder was made with the help of ICHD-2 and DSM-IV-TR criteria, respectively. Sleep history was gathered. Severity of RLS and insomnia was measured using IRLS (Hindi version and insomnia severity index Hindi version, respectively. Chi-square test, one way ANOVA and t-test were applied to find out the significance. Results: Primary headache was seen in 51.5% cases of RLS. Migraine was reported by 44.4% subjects and other types of ′primary headaches′ were reported by 7.1% subjects. Subjects were divided into- RLS; RLS with migraine and RLS with other headache. Females outnumbered in migraine subgroup (χ2 =16.46, P<0.001. Prevalence of depression (χ2 =3.12, P=0.21 and family history of RLS (χ2 =2.65, P=0.26 were not different among groups. Severity of RLS (P=0.22 or insomnia (P=0.43 were also similar. Conclusion: Migraine is frequently found in RLS patients in clinic based samples. Females with RLS are prone to develop migraine. Depression and severity of RLS or insomnia do not affect development of headache.

  12. Peripheral Dopamine in Restless Legs Syndrome

    Directory of Open Access Journals (Sweden)

    Ulrike H. Mitchell

    2018-03-01

    Full Text Available Objective/BackgroundRestless Legs Syndrome (RLS is a dopamine-dependent disorder characterized by a strong urge to move. The objective of this study was to evalulate blood levels of dopamine and other catecholamines and blood D2-subtype dopamine receptors (D2Rs in RLS.Patients/MethodsDopamine levels in blood samples from age-matched unmedicated RLS subjects, medicated RLS subjects and Controls were evaluated with high performance liquid chromatography and dopamine D2R white blood cell (WBC expression levels were determined with fluorescence-activated cell sorting and immunocytochemistry.ResultsBlood plasma dopamine levels, but not norepinepherine or epinephrine levels, were significantly increased in medicated RLS subjects vs unmedicated RLS subjects and Controls. The percentage of lymphocytes and monocytes expressing D2Rs differed between Control, RLS medicated and RLS unmedicated subjects. Total D2R expression in lymphocytes, but not monocytes, differed between Control, RLS medicated and RLS unmedicated subjects. D2Rs in lymphocytes, but not monocytes, were sensitive to dopamine in Controls only.ConclusionDownregulation of WBCs D2Rs occurs in RLS. This downregulation is not reversed by medication, although commonly used RLS medications increase plasma dopamine levels. The insensitivity of monocytes to dopamine levels, but their downregulation in RLS, may reflect their utility as a biomarker for RLS and perhaps brain dopamine homeostasis.

  13. [Innovative therapy for leg ulcers: Electrostimulation].

    Science.gov (United States)

    Maillard, H

    2015-01-01

    Chronic wounds can take a long time to heal despite appropriate therapy based upon aetiology and use of suitable dressings. The success of electrostimulation is based upon the existence within the skin of the endogenous currents involved in the wound healing process. Where skin continuity is broken by a wound, these electrical potentials are short-circuited, resulting in leakage of electrical current. Woundel(®) therapy is the only such treatment currently available in France and is based on the use of continuous pulsed current that generates an electrical field near the endogenous electrical fields. It utilises a console to deliver the electrical impulses, a dressing electrode and a dispersion electrode. The electrode dressing is left on the wound for 3 days, and venous compression bandaging may be applied to the leg, taking care to leave the connector free. Negative polarity stimulates migration of fibroblasts, resulting in elimination of fibrin. Positive polarity causes keratinocyte migration, which in turn leads to epidermisation. Electrostimulation is of recognised utility in the healing of chronic wounds: it has been assigned a high-level recommendation in the European and American guidelines for the treatment of venous ulcers and bedsores with proof level of A. Further, the analgesic effect of electrostimulation has been demonstrated in several studies. Electrostimulation is already well developed in France among wound specialists, but prospective studies are planned so that it may be used at patients' homes. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. Adjuvant Biological Therapies in Chronic Leg Ulcers

    Directory of Open Access Journals (Sweden)

    Natalia Burgos-Alonso

    2017-11-01

    Full Text Available Current biological treatments for non-healing wounds aim to address the common deviations in healing mechanisms, mainly inflammation, inadequate angiogenesis and reduced synthesis of extracellular matrix. In this context, regenerative medicine strategies, i.e., platelet rich plasmas and mesenchymal stromal cell products, may form part of adjuvant interventions in an integral patient management. We synthesized the clinical experience on ulcer management using these two categories of biological adjuvants. The results of ten controlled trials that are included in this systematic review favor the use of mesenchymal stromal cell based-adjuvants for impaired wound healing, but the number and quality of studies is moderate-low and are complicated by the diversity of biological products. Regarding platelet-derived products, 18 controlled studies investigated their efficacy in chronic wounds in the lower limb, but the heterogeneity of products and protocols hinders clinically meaningful quantitative synthesis. Most patients were diabetic, emphasizing an unmet medical need in this condition. Overall, there is not sufficient evidence to inform routine care, and further clinical research is necessary to realize the full potential of adjuvant regenerative medicine strategies in the management of chronic leg ulcers.

  15. Dissociation of periodic leg movements from arousals in restless legs syndrome.

    Science.gov (United States)

    Manconi, Mauro; Ferri, Raffaele; Zucconi, Marco; Bassetti, Claudio L; Fulda, Stephany; Aricò, Debora; Ferini-Strambi, Luigi

    2012-06-01

    The purpose of this study was to characterize the nature of the relation between periodic leg movements during sleep (PLMS) and cortical arousals to contribute to the debate on the clinical significance and treatment of PLMS. A prospective, placebo-controlled, single-blind, parallel group study was carried out including 46 drug-naive patients with idiopathic restless legs syndrome (RLS). Each patient underwent 2 consecutive full-night polysomnographic studies. The first night was the baseline night. Prior to the second night, 1 group received a single oral dose of 0.25mg pramipexole, whereas a second group received a single oral dose of 0.5mg clonazepam, and the remaining patients received placebo. Sleep stages, cyclic alternating pattern (CAP), and leg movement activity were scored following standard criteria; symptoms of RLS were also assessed. Pramipexole suppressed PLMS without affecting electroencephalographic (EEG) instability (CAP) and arousals (corresponding to CAP A3 and, partially, A2 subtypes), whereas clonazepam did the opposite, reducing non-rapid eye movement sleep EEG instability without effects on PLMS. Both drugs were effective on sensory RLS symptoms. This study demonstrates that a selective pharmacological approach can disconnect PLMS from arousal events, suggesting an indirect relation between each other. These results might weaken the hypothesis of a direct pathological role of PLMS in sleep disruption and can be important for the discussion on the existence of a distinct entity called periodic limb movements disorder. Moreover, the study opens the doors to the possibility of a joint treatment for RLS targeting sensory and motor symptoms, as well as sleep instability. Copyright © 2012 American Neurological Association.

  16. RELIABILITY OF KINEMATICS AND KINETICS ASSOCIATED WITH HORIZONTAL SINGLE LEG DROP JUMP ASSESSMENT. A BRIEF REPORT

    Directory of Open Access Journals (Sweden)

    Markus Stålbom

    2007-06-01

    Full Text Available Determining the reliability of a unilateral horizontal drop jump for displacement provided the focus for this research. Eighteen male subjects were required to step off a 20cm box and land on a force plate with one leg and thereafter jump for maximal horizontal displacement on two different days. Dependent variables from the jump assessment included mean and peak vertical (V and horizontal (H ground reaction forces (GRF and impulses, horizontal displacement and contact time. The between-trial variability of all kinematic and kinetic measures was less than 7%. The most consistent measure over both trials was the horizontal displacement jumped (1.2 to 1.4% and the most variable were the contact time the first day (6.5% and peak HGRF the second day (4.3%. In all cases there was less variation associated with the second rather than the first day. In terms of test-retest variability the percent changes in the means and coefficient of variations (CVs were all under 10%. The smallest changes in the mean (0.43 %, least variation (< 2.26 % and second highest intraclass correlation co-efficient (ICC = 0.95 were found for horizontal displacement jumped. The highest ICC (0.96 was found for horizontal impulse. Given the reliability of the single leg drop jump, it may offer better prognostic and diagnostic information than that obtained with bilateral vertical jumps

  17. Sympathetic nervous system activation reduces contraction-induced rapid vasodilation in the leg of humans independent of age.

    Science.gov (United States)

    Hughes, William E; Kruse, Nicholas T; Casey, Darren P

    2017-07-01

    Contraction-induced rapid vasodilation is attenuated similarly in the upper and lower limbs of older adults. In the forearm, this attenuation is in part due to a greater sympathetic vasoconstriction. We examined whether the age-related reduction in contraction-induced vasodilation in the leg is also due to a sympathetic vasoconstrictive mechanism. Thirteen young (24 ± 1 yr) and twelve older adults (67 ± 1 yr) performed single-leg knee extension at 20 and 40% of work-rate maximum (WR max ) during control and cold-pressor test (CPT) conditions. Femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC; ml·min -1 ·mmHg -1 ) was calculated using blood flow (ml/min) and mean arterial pressure (mmHg). Peak (ΔVC from baseline) and total VC were blunted in older adults during control conditions across exercise intensities ( P ROV). Within the forearm, this attenuation is partially due to enhanced sympathetic vasoconstriction. In the current study, we found that sympathetic vasoconstriction reduces contraction-induced ROV within the leg of both young and older adults, with the magnitude of change being similar between age groups. Our current results suggest that age-related attenuations in contraction-induced ROV within the leg are not fully explained by a sympathetic vasoconstrictor mechanism. Copyright © 2017 the American Physiological Society.

  18. Restless legs syndrome, periodic leg movements, and periodic limb movement disorder in children.

    Science.gov (United States)

    Durmer, Jeffrey S; Quraishi, Ghazala H

    2011-06-01

    The characteristic symptoms of restless legs syndrome (RLS) have been known for hundreds of years and were first reported in medicine in the 1600s. Clinicians must consider potential mimics, comorbid, and associated conditions when evaluating children with RLS symptoms. The traditional differentiation of RLS from periodic limb movement disorder (PLMD) is noted in children as well as adults. Because current pediatric RLS research is sparse, this article provides the most up-to-date evidence-based as well as consensus opinion-based information on the subject of childhood RLS and PLMD. Prevalence, pathophysiology, diagnosis, treatment, and clinical associations are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Individual Leg and Joint Work during Sloped Walking for People with a Transtibial Amputation Using Passive and Powered Prostheses

    Directory of Open Access Journals (Sweden)

    Jana R. Jeffers

    2017-12-01

    Full Text Available People with a transtibial amputation using passive-elastic prostheses exhibit reduced prosthetic ankle power and push-off work compared to non-amputees and compensate by increasing their affected leg (AL hip joint work and unaffected leg (UL ankle, knee, and hip joint and leg work during level-ground walking. Use of a powered ankle–foot prosthesis normalizes step-to-step transition work during level-ground walking over a range of speeds for people with a transtibial amputation, but the effects on joint work during level-ground, uphill, and downhill walking have not been assessed. We investigated how use of passive-elastic and powered ankle–foot prostheses affect leg joint biomechanics during level-ground and sloped walking. 10 people with a unilateral transtibial amputation walked at 1.25 m/s on a dual-belt force-measuring treadmill at 0°, ±3°, ±6°, and ±9° using their own passive-elastic and a powered prosthesis (BiOM T2, BionX Medical Technologies, Inc., Bedford, MA, USA while we measured kinematic and kinetic data. We calculated AL and UL prosthetic, ankle, knee, hip, and individual leg positive, negative, and net work. Use of a powered compared to passive-elastic ankle–foot prosthesis resulted in greater AL prosthetic and individual leg net work on uphill and downhill slopes. Over a stride, AL prosthetic positive work was 23–30% greater (p < 0.05 during walking on uphill slopes of +6°, and +9°, prosthetic net work was up to 10 times greater (more positive (p ≤ 0.005 on all uphill and downhill slopes and individual leg net work was 146 and 82% more positive (p < 0.05 at uphill slopes of +6° and +9°, respectively, with use of the powered compared to passive-elastic prosthesis. Greater prosthetic positive and net work through use of a powered ankle–foot prosthesis during uphill and downhill walking improves mechanical work symmetry between the legs, which could decrease metabolic cost and improve functional

  20. Arc parallel extension in Higher and Lesser Himalayas, evidence ...

    Indian Academy of Sciences (India)

    extension determined based on geodetically computed extension rate and age of initiation of rifting in southern ..... sive distribution of these extensional structures in the Lesser Himalayas, we analysed incised fluvial terrace deposits. In the eastern Himalaya, the MCT ..... and Duncan C 2006 Climatic forcing of erosion, land-.

  1. Android Access Control Extension

    Directory of Open Access Journals (Sweden)

    Anton Baláž

    2015-12-01

    Full Text Available The main objective of this work is to analyze and extend security model of mobile devices running on Android OS. Provided security extension is a Linux kernel security module that allows the system administrator to restrict program's capabilities with per-program profiles. Profiles can allow capabilities like network access, raw socket access, and the permission to read, write, or execute files on matching paths. Module supplements the traditional Android capability access control model by providing mandatory access control (MAC based on path. This extension increases security of access to system objects in a device and allows creating security sandboxes per application.

  2. Leg and arm lactate and substrate kinetics during exercise

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Jensen-Urstad, M; Rosdahl, H

    2003-01-01

    To study the role of muscle mass and muscle activity on lactate and energy kinetics during exercise, whole body and limb lactate, glucose, and fatty acid fluxes were determined in six elite cross-country skiers during roller-skiing for 40 min with the diagonal stride (Continuous Arm + Leg) followed...... by 10 min of double poling and diagonal stride at 72-76% maximal O(2) uptake. A high lactate appearance rate (R(a), 184 +/- 17 micromol x kg(-1) x min(-1)) but a low arterial lactate concentration ( approximately 2.5 mmol/l) were observed during Continuous Arm + Leg despite a substantial net lactate...... release by the arm of approximately 2.1 mmol/min, which was balanced by a similar net lactate uptake by the leg. Whole body and limb lactate oxidation during Continuous Arm + Leg was approximately 45% at rest and approximately 95% of disappearance rate and limb lactate uptake, respectively. Limb lactate...

  3. Development and Physical Control Research on Prototype Artificial Leg

    Directory of Open Access Journals (Sweden)

    Fei Li

    2016-03-01

    Full Text Available To provide an ideal platform for research on intelligent bionic leg (IBL, this paper proposes a model of a biped robot with heterogeneous legs (BRHL. A prototype of an artificial leg is developed based on biological structure and motion principle analysis of human lower extremities. With regard to the driving sources, servomotors are chosen for the hip joint and ankle joint, while pneumatic muscle actuators (PMAs are chosen for the knee joint. The control system of the bionic artificial leg is designed and a physical experimental platform is established. The physical control experiments are done based on proportional-integral-derivative (PID control strategy. The experimental results show that such a system can realize the expected goals.

  4. Eyelash Transplantation Using Leg Hair by Follicular Unit Extraction

    Directory of Open Access Journals (Sweden)

    Sanusi Umar, MD

    2015-03-01

    Full Text Available Summary: Fine hairs of the head and nape areas have been used as donor sources in eyelash transplantation but are straight, coarse, and grow rapidly, requiring frequent eyelash maintenance. This is the first reported case of eyelash transplantation by follicular unit extraction using leg hair as a donor source; findings were compared with that of another patient who underwent a similar procedure with donor hairs from the nape area. Although both patients reported marked improvement in fullness of eyelashes within 3 months postsurgery, the transplanted leg hair eyelashes required less frequent trimming (every 5–6 weeks compared with nape hair eyelashes (every 2–3 weeks. Additionally, in leg hair eyelashes, the need for perming to sustain a natural looking eyelash curl was eliminated. Eyelash transplantation using leg donor hair in hirsute women may result in good cosmetic outcomes and require less maintenance compared with nape donor hair.

  5. Leg ulcers in sickle cell patients: management challenges

    Directory of Open Access Journals (Sweden)

    El Khatib AM

    2016-11-01

    Full Text Available Arij M El Khatib,1 Shady N Hayek2 1Division of Plastic and Reconstructive Surgery, Department of Surgery, American University of Beirut Medical Center (AUBMC, 2Private Practice, Cosmetic Surgery Center, Beirut, Lebanon Abstract: Sickle cell disease is an autosomal recessive hemoglobinopathy caused by an amino acid substitution from glutamic acid to valine in the beta hemoglobin chain. One of the common symptoms occurring in sickle cell patients are leg ulcers, which are notoriously painful, difficult to treat, and frequently recurrent. These ulcers pose a therapeutic challenge with multiple modalities proposed for treatment, but with scarce evidence of efficacy of any single modality. Ulcer prevention, rigorous wound care, pain control, and surgery are the current mainstays of sickle cell leg ulcer treatment. Keywords: sickle cell leg ulcer, leg wound, sickle cell disease 

  6. Hereditary Lymphedema of the Leg – A Case Report

    Directory of Open Access Journals (Sweden)

    Birgit Heinig

    2017-07-01

    Full Text Available Primary of hereditary lymphedema is a rare but progressive disease. It is yet not curable. We present a 48-year-old male patient with hereditary lymphedema of his left leg, that was realised by minor trauma (able twist when he was seven years old. He had never been treated for lymphedema but experienced multiple erysipelas during his life. After diagnostic procedures to exclude other causes of leg swelling, the diagnosis of hereditary lymphedema of the leg, stage III was confirmed. We initialized complex decongestive therapy. During two weeks of intensive treatment, the circumference of the left leg could be reduced by 10 cm. This case illustrates the "natural course" hereditary lymphedema. But it raises the hope that even after decades of ignorance, the patients benefits from complex decongestive treatment. Therapeutic nihilism is unnecessary and poses lymphedema patients to risks of infection and secondary malignancies like Stewart-Trewes syndrome.

  7. Periodic Limb Movement Disorder (PLMD) and Restless Legs Syndrome (RLS)

    Science.gov (United States)

    ... the syndrome. Risk factors include the following: A sedentary lifestyle Smoking Obesity Many people with narcolepsy or rapid eye movement (REM) behavior disorder move their legs periodically during sleep. Both ...

  8. Quality of Life in People with Leg Ulcer, Integrative Review

    Directory of Open Access Journals (Sweden)

    Daniela Alves

    2016-04-01

    Full Text Available Objective: To identify the main changes in the daily life of people with leg ulcer and how that affects the person’s quality of life. Methodology: We used the methodology PI [C] OD and selected four research articles, taken from EBSCO, PubMed, and EWMA. Results: The main changes identified in the people’s daily live with leg ulcers are physical (pain, decreased mobility, presence of exudate, bad smell from the wound and change in the style of clothing, psychological (sleep disorders, depression, anxiety, feelings of rejection and low self-steem, social (isolation, restriction in leisure activities, inability to perform household chores. Conclusions: The literature about the person’s quality of life with leg ulcer reported a significant impact in the daily life. The care provided by nurses should be centered on the person, integrating all the kind of needs and the leg ulcer must not be the sole focus of care

  9. Intramuscular fiber conduction velocity, isometric force and explosive performance

    Directory of Open Access Journals (Sweden)

    Methenitis Spyridon

    2016-06-01

    Full Text Available Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fifteen moderately-trained young females performed countermovement jumps as well as an isometric leg press test in order to determine the rate of force development and maximum isometric force. Vastus lateralis MFCV was measured with intramuscular microelectrodes at rest on a different occasion. Maximum MFCV was significantly correlated with maximum isometric force (r = 0.66, p < 0.01, nevertheless even closer with the leg press rate of force development at 100 ms, 150 ms, 200 ms, and 250 ms (r = 0.85, r = 0.89, r = 0.91, r = 0.92, respectively, p < 0.01. Similarly, mean MFCV and type II MFCV were better correlated with the rate of force development than with maximum isometric leg press force. Lower, but significant correlations were found between mean MFCV and countermovement jump power (r = 0.65, p < 0.01. These data suggest that muscle fiber conduction velocity is better linked with the rate of force development than with isometric force, perhaps because conduction velocity is higher in the larger and fastest muscle fibers which are recognized to contribute to explosive actions.

  10. The pathophysiology of restless legs syndrome

    International Nuclear Information System (INIS)

    Miyamoto, Masayuki; Miyamoto, Tomoyuki; Iwanami, Masaoki; Suzuki, Keisuke; Hirata, Koichi

    2009-01-01

    Restless legs syndrome (RLS) is a sensorimotor disorder that is frequently associated with periodic leg movements (PLMS). RLS is generally considered to be a central nervous system (CNS)-related disorder although no specific lesion has been found to be associated with the syndrome. Reduced intracortical inhibition has been demonstrated in RLS by transcranial magnetic stimulation. Some MRI studies have revealed the presence of morphologic changes in the somatosensory cortex, motor cortex and thalamic gray matter. The results of single photon emission computed tomography (SPECT) and positron emission tomography (PET) studies showed that the limbic and opioid systems also play important roles in the pathophysiology of RLS. A functional MRI study revealed abnormal bilateral cerebellar and thalamic activation during the manifestation of sensory symptoms, with additional red nucleus and reticular formation activity during PLMS. PLMS is likely to occur in patients with spinal cord lesions, and some patients with sensory polyneuropathy may exhibit RLS symptoms. RLS symptoms seem to depend on abnormal spinal sensorimotor integration at the spinal cord level and abnormal central somatosensory processing. PLMS appears to depend on increased excitability of the spinal cord and a decreased supraspinal inhibitory mechanism from the A11 diencephalic dopaminergic system. RLS symptoms respond very dramatically to dopaminergic therapy. The results of analysis by PET and SPECT studies of striatal D2 receptor binding in humans are inconclusive. However, studies in animal models suggest that the participation of the A11 dopaminergic system and the D3 receptor in RLS symptoms. The symptoms of RLS are aggravated in those with iron deficiency, and iron treatment ameliorates the symptoms in some patients. Neuroimaging studies, analysis of the cerebrospinal fluid, and studies on postmortem tissue and use of animal models have indicated that low brain iron concentrations and dysfunction of

  11. Numerical Estimation of Balanced and Falling States for Constrained Legged Systems

    Science.gov (United States)

    Mummolo, Carlotta; Mangialardi, Luigi; Kim, Joo H.

    2017-08-01

    Instability and risk of fall during standing and walking are common challenges for biped robots. While existing criteria from state-space dynamical systems approach or ground reference points are useful in some applications, complete system models and constraints have not been taken into account for prediction and indication of fall for general legged robots. In this study, a general numerical framework that estimates the balanced and falling states of legged systems is introduced. The overall approach is based on the integration of joint-space and Cartesian-space dynamics of a legged system model. The full-body constrained joint-space dynamics includes the contact forces and moments term due to current foot (or feet) support and another term due to altered contact configuration. According to the refined notions of balanced, falling, and fallen, the system parameters, physical constraints, and initial/final/boundary conditions for balancing are incorporated into constrained nonlinear optimization problems to solve for the velocity extrema (representing the maximum perturbation allowed to maintain balance without changing contacts) in the Cartesian space at each center-of-mass (COM) position within its workspace. The iterative algorithm constructs the stability boundary as a COM state-space partition between balanced and falling states. Inclusion in the resulting six-dimensional manifold is a necessary condition for a state of the given system to be balanced under the given contact configuration, while exclusion is a sufficient condition for falling. The framework is used to analyze the balance stability of example systems with various degrees of complexities. The manifold for a 1-degree-of-freedom (DOF) legged system is consistent with the experimental and simulation results in the existing studies for specific controller designs. The results for a 2-DOF system demonstrate the dependency of the COM state-space partition upon joint-space configuration (elbow-up vs

  12. Homomorphisms between C∗ -algebra extensions

    Indian Academy of Sciences (India)

    C∗. -algebra extensions, Ext groups do not classify extension algebras. So one has to study the isomorphism equivalence of extensions. In fact, a homomorphism between two extension algebras may not map the essential ideal into the other in general, so we have to consider properties of extension homomorphisms.

  13. Mobile Applications for Extension

    Science.gov (United States)

    Drill, Sabrina L.

    2012-01-01

    Mobile computing devices (smart phones, tablets, etc.) are rapidly becoming the dominant means of communication worldwide and are increasingly being used for scientific investigation. This technology can further our Extension mission by increasing our power for data collection, information dissemination, and informed decision-making. Mobile…

  14. Extensions of tempered representations

    NARCIS (Netherlands)

    Opdam, E.; Solleveld, M.

    2013-01-01

    Let π, π′ be irreducible tempered representations of an affine Hecke algebra H with positive parameters. We compute the higher extension groups Ext nH(π,π′) explicitly in terms of the representations of analytic R-groups corresponding to π and π′. The result has immediate applications to the

  15. Journal of Agricultural Extension

    African Journals Online (AJOL)

    Mission Statement The mission of the "Journal of Agricultural Extension" is to publish conceptual papers and empirical research that tests, extends, or builds ... Symbol recognition and interpretation of HIV/AIDS pictorial messages among rural women in Abia State Nigeria · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  16. Criteria in diagnosing nocturnal leg cramps: a systematic review.

    Science.gov (United States)

    Hallegraeff, Joannes; de Greef, Mathieu; Krijnen, Wim; van der Schans, Cees

    2017-02-28

    Up to 33% of the general population over 50 years of age are affected by nocturnal leg cramps. Currently there are no generally accepted clinical characteristics, which identify nocturnal leg cramps. This study aims to identify these clinical characteristics and to differentiate between them and the characteristics of restless leg syndrome and periodic limb disorder. A systematic literature study was executed from December 2015 to May 2016. This study comprised of a systematic literature review of randomized clinical trials, observational studies on nocturnal and rest cramps of legs and other muscles, and other systematic and narrative reviews. Two researchers independently extracted literature data and analyzed this using a standardized reviewing protocol. Modified versions of the Cochrane Collaboration tools assessed the risk of bias. A Delphi study was conducted to assess agreement on the characteristics of nocturnal leg cramps. After systematic and manual searches, eight randomized trials and ten observational studies were included. On the basis of these we identified seven diagnostic characteristics of nocturnal leg cramps: intense pain, period of duration from seconds to maximum 10 minutes, location in calf or foot, location seldom in thigh or hamstrings, persistent subsequent pain, sleep disruption and distress. The seven above characteristics will enhance recognition of the condition, and help clinicians make a clear distinction between NLC and other sleep-related musculoskeletal disorder among older adults.

  17. Straight leg elevation to rule out pelvic injury.

    Science.gov (United States)

    Bolt, Caroline; O'Keeffe, Francis; Finnegan, Pete; Dickson, Kristofer; Smit, De Villiers; Fitzgerald, Mark C; Mitra, Biswadev

    2018-02-01

    Pelvic x-ray is frequently used as a screening tool during initial assessment of injured patients. However routine use in the awake and alert blunt trauma patient may be questioned due to low yield. We propose a clinical tool that may avoid unnecessary imaging by examining whether the ability to straight leg raise, without pain, can rule out pelvic injury. We conducted a prospective cohort study with the exposure variables of ability to straight leg raise and presence of pain on doing so, and presence of pelvic fracture on x-ray as the primary outcome variable. Of the 328 participants, 35 had pelvic fractures, and of these 32 were either unable to straight leg raise, or had pain on doing so, with a sensitivity of 91.43% (95% CI: 76.94-98.2%) and a negative predictive value of 98.57% (95% CI: 95.88-99.70%). The 3 participants with a pelvic fracture who could straight leg raise with no pain, all had a GCS of less than 15, and therefore, among the sub-group of patients with GCS15, a 100% sensitivity and 100% negative predictive value for straight leg raise with no pain to rule out pelvic fracture was demonstrated. Among awake, alert patients, painless straight leg raise can exclude pelvic fractures and be incorporated into initial examination during reception and resuscitation of injured patients. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  18. High resolution unenhanced computed tomography in patients with swollen legs.

    Science.gov (United States)

    Monnin-Delhom, E D; Gallix, B P; Achard, C; Bruel, J M; Janbon, C

    2002-09-01

    To evaluate the accuracy of computed tomography (CT) scan imaging in distinguishing lymphedema from deep venous thrombosis (DVT) and lipodystrophy (lipedema) in patients with swollen legs. CT scans of the lower limbs were performed in 55 patients with 76 swollen legs (44 lymphedemas, 12 DVT and 20 lipedemas). Thirty-four normal contralateral legs were also similarly evaluated. Primary lymphedema was verified by lymphography or lymphoscintigraphy, whereas secondary lymphedema was documented by a typical clinical history. DVT was established by ultrasound Doppler imaging. The diagnosis of lipedema was made with bilateral swollen legs where lymphoscintigraphy and Doppler examination were both unremarkable. Qualitative CT analysis was based on skin thickening, subcutaneous edema accumulation with a honeycombed pattern, and muscle compartment enlargement. Sensitivity and specificity of CT scan for the diagnosis of lymphedema was 93 and 100%, respectively; for lipedema it was 95 and 100%, respectively; andfor DVT it was 91 and 99%, respectively. Skin thickening was found in 42 lymphedemas (95%), in 9 DVT (75%), and in 2 lipedemas (16%). Subcutaneous edema accumulation was demonstrated in 42 legs (95%) with lymphedema and in 5 (42%) with DVT but in none with lipedema. A honeycombed pattern was present only in lymphedema (18 legs or 41%); muscle enlargement was present in all patients with DVT, in no patient with lipedema, and in 4 (9%) with lymphedema. Edema accumulation is readily demonstrated with plain CT scan and is not present in lipedema. Specific CT features of the subcutaneous fat and muscle compartments allow accurate differentiation between lymphedema and DVT.

  19. Treatment Failure and Leg Amputation Among Patients With Foot Osteomyelitis.

    Science.gov (United States)

    Barshes, Neal R; Mindru, Cezarina; Ashong, Chester; Rodriguez-Barradas, Maria; Trautner, Barbara W

    2016-12-01

    We sought to identify factors associated with treatment failure and leg amputations among those patients who presented with foot osteomyelitis. Characteristics, treatments, and outcomes for all patients treated for probable or definite foot osteomyelitis (per consensus definition) between January 2011 and March 2015 were reviewed. Multivariate Cox regression models were used to identify risk factors for treatment failure (unanticipated resection of additional bone or leg amputation) and of leg amputation alone. A total of 184 episodes of foot osteomyelitis met inclusion criteria. Treatment failure occurred in 53 (28.8%) and leg amputation in 21 (11.4%). Risk factors for treatment failure included severe/unaddressed peripheral artery disease, homelessness, Pseudomonas aeruginosa or Escherichia coli bone isolates, serum albumin <2.8 mg/dL, hallux involvement, insulin therapy, 60 or more pack-years smoking, and <7 days of directed antibiotic therapy for a positive bone margin. Delayed primary wound closure (ie, staged operations) had significantly lower treatment failure risk. Unanticipated resection of bone was not associated with leg amputation. Foot osteomyelitis treatment failure is common. Various factors can help identify those at risk for treatment failure and/or leg amputation, and further studies should focused whether initial management or follow-up should change when these factors are present.

  20. Transforming the Albanian Armed Forces, Overcoming the Challenges

    National Research Council Canada - National Science Library

    Cahani, Nazmi

    2009-01-01

    The Albanian Armed Forces (AAF) are currently undergoing an extensive defense reform process that consists of transformation of its strategic concept, doctrine, organizational structure, personnel management system, military...