IS ENHANCED-ECCENTRIC RESISTANCE TRAINING SUPERIOR TO TRADITIONAL TRAINING FOR INCREASING ELBOW FLEXOR STRENGTH?

Directory of Open Access Journals (Sweden)

Thomas W. Kaminski

2003-06-01

Full Text Available Protocols for strengthening muscle are important for fitness, rehabilitation, and the prevention of myotendinous injuries. In trained individuals, the optimal method of increasing strength remains unclear. The purpose of this study was to compare the effects of a traditional method of strengthening with a method that allowed for enhanced-eccentric training, on changes in elbow flexor strength in trained subjects. Thirty-nine (8 male, 31 female trained subjects with normal elbow function participated in this study. Subjects were rank-ordered according to isometric force production and randomly assigned to one of three training groups: control (CONT, traditional concentric/eccentric (TRAD, and concentric/enhanced-eccentric (NEG. The training groups completed 24 training sessions. An evaluator blinded to training group performed all testing. Mixed model ANOVA techniques were used to determine if differences existed in concentric one repetition maximum strength, and isometric force production among groups. Changes in peak and average isokinetic force production were also compared. Type 1 error was maintained at 5%. While both groups improved concentric one repetition maximum (NEG = 15.5%, TRAD = 13.8% neither training group statistically differed from changes demonstrated by the CONT group. Nor did either training group show significant improvements in isometric or isokinetic force production over the CONT group. These results do not support the superiority of enhanced-eccentric training for increasing force production in trained subjects.

Improving the seismic performance of eccentrically braced frames by using a ductile element

Directory of Open Access Journals (Sweden)

Morteza Naghipour

2017-11-01

Full Text Available Stability of structures against earthquake is much important to prevent total or partial failure of structures and loss of financial and human investments of people and country. Eccentrically braced frames, as one of the most commonly used earthquake resistant systems, with good ductility and toughness, have different arrangements; one of them is Link beam-to-column connection. This type of connection was considered as bending form before the North Ridge earthquake (1994. But conducted research after the North Ridge Earthquake showed that the link beam-to-column connections were subjected to brittle failure, similar to connections which were located in Moment frames. So, after the North Ridge Earthquake, researchers began looking for ways to improve these types of connections, which indicates necessity of research in this field more than before. In this study, a new type of Energy absorption was introduced.  This absorption consists of a ring which increases the ductility and energy absorption of earthquake and a box to increase the bearing capacity which is connected to the ring through connection plates. for evaluating the performance of the proposed elements in steel frames with eccentrically braces, under nonlinear time history analysis, the OpenSees software has been used. The obtained Hysteresis curves suggest that introduced element can act as an energy absorbing member and a fuse to Reducing damage to structures with reduced rotation of link-beam, Cutting base and Relative story displacement in addition to providing the necessary ductility.

Eccentric Torque-Producing Capacity is Influenced by Muscle Length in Older Healthy Adults.

Science.gov (United States)

Melo, Ruth C; Takahashi, Anielle C M; Quitério, Robison J; Salvini, Tânia F; Catai, Aparecida M

2016-01-01

Considering the importance of muscle strength to functional capacity in the elderly, the study investigated the effects of age on isokinetic performance and torque production as a function of muscle length. Eleven younger (24.2 ± 2.9 years) and 16 older men (62.7 ± 2.5 years) were subjected to concentric and eccentric isokinetic knee extension/flexion at 60 and 120° · s(-1) through a functional range of motion. The older group presented lower peak torque (in newton-meters) than the young group for both isokinetic contraction types (age effect, p torque deficits in the older group were near 30 and 29% for concentric and eccentric contraction, respectively. Concentric peak torque was lower at 120° · s(-1) than at 60° · s(-1) for both groups (angular velocity effect, p torque was the only exercise tested that showed an interaction effect between age and muscle length (p torque responses to the muscle length between groups. Compared with the young group, the eccentric knee extension torque was 22-56% lower in the older group, with the deficits being lower in the shortened muscle length (22-27%) and higher (33-56%) in the stretched muscle length. In older men, the production of eccentric knee strength seems to be dependent on the muscle length. At more stretched positions, older subjects lose the capacity to generate eccentric knee extension torque. More studies are needed to assess the mechanisms involved in eccentric strength preservation with aging and its relationship with muscle length.

Effect of load eccentricity and stress level on monopile support for offshore wind turbines

DEFF Research Database (Denmark)

Klinkvort, Rasmus Tofte; Hededal, Ole

2014-01-01

on which load is applied with a large eccentricity. With centrifuge tests as the basis, this paper investigates the behaviour of a rigid pile loaded with a high eccentricity. A test series was carried out to simulate idealized monotonic load cases for monopiles supporting an offshore wind turbine....... Centrifuge tests were performed on model monopiles subjected to stress distributions equal to prototype monopiles with pile diameters ranging from 1–5 m and eccentricities ranging from 8.25–17.75 pile diameters. It was possible to identify a unified response of all of these tests by using dimensional...... analysis and Rankine’s passive earth pressure coefficient as a normalization parameter. The normalized ultimate soil resistance was unaffected by acceleration level and load eccentricity, indicating that the failure mechanism was the same for all tests. Based on the centrifuge tests, a reformulation...

Flow Mode Magnetorheological Dampers with an Eccentric Gap

OpenAIRE

Young-Tai Choi; Norman M. Wereley

2014-01-01

This paper analyzes flow mode magnetorheological (MR) dampers with an eccentric annular gap (i.e., a nonuniform annular gap). To this end, an MR damper analysis for an eccentric annular gap is constructed based on approximating the eccentric annular gap using a rectangular duct with a variable gap, as well as a Bingham-plastic constitutive model of the MR fluid. Performance of flow mode MR dampers with an eccentric gap was assessed analytically using both field-dependent damping force and dam...

Flow Mode Magnetorheological Dampers with an Eccentric Gap

Directory of Open Access Journals (Sweden)

Young-Tai Choi

2014-07-01

Full Text Available This paper analyzes flow mode magnetorheological (MR dampers with an eccentric annular gap (i.e., a nonuniform annular gap. To this end, an MR damper analysis for an eccentric annular gap is constructed based on approximating the eccentric annular gap using a rectangular duct with a variable gap, as well as a Bingham-plastic constitutive model of the MR fluid. Performance of flow mode MR dampers with an eccentric gap was assessed analytically using both field-dependent damping force and damping coefficient, which is the ratio of equivalent viscous field-on damping to field-off damping. In addition, damper capabilities of flow mode MR dampers with an eccentric gap were compared to a concentric gap (i.e., uniform annular gap.

Effects of Plyometric Versus Concentric and Eccentric Conditioning Contractions on Upper-Body Postactivation Potentiation.

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Ulrich, Gert; Parstorfer, Mario

2017-07-01

There are limited data on postactivation potentiation's (PAP) effects after plyometric conditioning contractions (CCs), especially in the upper body. This study compared plyometric CCs with concentric-eccentric and eccentric CCs aiming to improve upper-body power performance due to a PAP effect. Sixteen resistance-trained males completed 3 experimental trials in a randomized order that comprised either a plyometric (PLY), a concentric-eccentric (CON), or an eccentric-only (ECC) CC. Maximal muscle performance, as determined by a ballistic bench-press throw, was measured before (baseline) and 1, 4, 8, 12, and 16 min after each CC. Compared with baseline, bench-press power was significantly enhanced only in CON (P = .046, ES = 0.21) after 8 min of recovery. However, the results obtained from the comparisons between baseline power performance and the individual best power performance for each subject after each CC stimulus showed significant increases in PLY (P < .001, ES = 0.31) and CON (P < .001, ES = 0.38). There was no significant improvement in ECC (P = .106, ES = 0.11). The results indicate that only CON CCs generated increases in bench-press power after 8 min of rest. However, considering an individual rest interval, PLY CCs led to an enhanced power performance in the bench-press exercise, and this increase was comparable to that induced by CON CCs. Due to the easy practical application before a competition, PLY CCs might be an interesting part of warm-up strategies aiming to improve upper-body power performance by reason of PAP.

Prolonged submaximal eccentric exercise is associated with increased levels of plasma IL-6

DEFF Research Database (Denmark)

Rohde, Thomas; MacLean, D A; Richter, Erik

1997-01-01

To study the relationship between exercise-related muscle proteolysis and the cytokine response, a prolonged eccentric exercise model of one leg was used. Subjects performed two trials [a branched-chain amino acid (BCAA) supplementation and a control trial]. The release of amino acids from muscle...... during and after the eccentric exercise was decreased in the BCAA trial, suggesting a suppression of net muscle protein degradation. The plasma concentrations of interleukin (IL)-6 increased from 0.75 +/- 0.19 (preexercise) to 5.02 +/- 0.96 pg/ml (2 h postexercise) in the control trial and in the BCAA...... supplementation trial from 1.07 +/- 0.41 to 4.15 +/- 1.21 pg/ml. Eccentric exercise had no effect on the concentrations of neutrophils, lymphocytes, CD16+/CD56+, CD4+, CD8+, CD14+/CD38+, lymphocyte proliferative response, or cytotoxic activities. BCAA supplementation reduced the concentration of CD14+/CD38+ cells...

Blood flow after contraction and cuff occlusion is reduced in subjects with muscle soreness after eccentric exercise

DEFF Research Database (Denmark)

Souza-Silva, Eduardo; Wittrup Christensen, Steffan; Hirata, Rogerio Pessoto

2018-01-01

Purpose: Delayed onset muscle soreness (DOMS) occur within 1-2 days after eccentric exercise but the mechanism mediating hypersensitivity is unclear. This study hypothesized that eccentric exercise reduces the blood flow response following muscle contractions and cuff occlusion, which may result ...

The mechanism for efficacy of eccentric loading in Achilles tendon injury; an in vivo study in humans.

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Rees, J D; Lichtwark, G A; Wolman, R L; Wilson, A M

2008-10-01

Degenerative disorders of tendons present an enormous clinical challenge. They are extremely common, prone to recur and existing medical and surgical treatments are generally unsatisfactory. Recently eccentric, but not concentric, exercises have been shown to be highly effective in managing tendinopathy of the Achilles (and other) tendons. The mechanism for the efficacy of these exercises is unknown although it has been speculated that forces generated during eccentric loading are of a greater magnitude. Our objective was to determine the mechanism for the beneficial effect of eccentric exercise in Achilles tendinopathy. Seven healthy volunteers performed eccentric and concentric loading exercises for the Achilles tendon. Tendon force and length changes were determined using a combination of motion analysis, force plate data and real-time ultrasound. There was no significant difference in peak tendon force or tendon length change when comparing eccentric with concentric exercises. However, high-frequency oscillations in tendon force occurred in all subjects during eccentric exercises but were rare in concentric exercises (P < 0.0001). These oscillations provide a mechanism to explain the therapeutic benefit of eccentric loading in Achilles tendinopathy and parallels recent evidence from bone remodelling, where the frequency of the loading cycles is of more significance than the absolute magnitude of the force.

Effects of resistance training using known vs unknown loads on eccentric-phase adaptations and concentric velocity.

Science.gov (United States)

Hernández-Davó, J L; Sabido, R; Behm, D G; Blazevich, A J

2018-02-01

The aims of this study were to compare both eccentric- and concentric-phase adaptations in highly trained handball players to 4 weeks of twice-weekly rebound bench press throw training with varying loads (30%, 50% and 70% of one-repetition maximum [1-RM]) using either known (KL) or unknown (UL) loads and to examine the relationship between changes in eccentric- and concentric-phase performance. Twenty-eight junior team handball players were divided into two experimental groups (KL or UL) and a control group. KL subjects were told the load prior each repetition, while UL were blinded. For each repetition, the load was dropped and then a rebound bench press at maximum velocity was immediately performed. Both concentric and eccentric velocity as well as eccentric kinetic energy and musculo-articular stiffness prior to the eccentric-concentric transition were measured. Results showed similar increases in both eccentric velocity and kinetic energy under the 30% 1-RM but greater improvements under 50% and 70% 1-RM loads for UL than KL. UL increased stiffness under all loads (with greater magnitude of changes). KL improved concentric velocity only under the 30% 1-RM load while UL also improved under 50% and 70% 1-RM loads. Improvements in concentric movement velocity were moderately explained by changes in eccentric velocity (R 2 =.23-.62). Thus, UL led to greater improvements in concentric velocity, and the improvement is potentially explained by increases in the speed (as well as stiffness and kinetic energy) of the eccentric phase. Unknown load training appears to have significant practical use for the improvement of multijoint stretch-shortening cycle movements. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of eccentric exercise on trapezius electromyography during computer work with active and passive pauses

DEFF Research Database (Denmark)

Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

2009-01-01

) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40s over 2 days, before, immediately and 24h after eccentric exercise. Surface EMG signals were recorded from four parts of the trapezius during computer work. FINDINGS: EMG amplitude during computer work decreased......BACKGROUND: The aim of this laboratory study was to investigate the effects of eccentric exercises on the trapezius muscle spatial electromyographic (EMG) activity during computer work with active and passive pauses. METHODS: Twelve healthy male subjects performed computer work with passive (relax...... immediately after exercise (Pwork with active pauses compared with passive ones (P

Change of Direction Speed: Toward a Strength Training Approach with Accentuated Eccentric Muscle Actions.

Science.gov (United States)

Chaabene, Helmi; Prieske, Olaf; Negra, Yassine; Granacher, Urs

2018-03-28

There is growing evidence that eccentric strength training appears to have benefits over traditional strength training (i.e., strength training with combined concentric and eccentric muscle actions) from muscular, neuromuscular, tendinous, and metabolic perspectives. Eccentric muscle strength is particularly needed to decelerate and stabilize the body during the braking phase of a jump exercise or during rapid changes of direction (CoD) tasks. However, surprisingly little research has been conducted to elucidate the effects of eccentric strength training or strength training with accentuated eccentric muscle actions on CoD speed performance. In this current opinion article, we present findings from cross-sectional studies on the relationship between measures of eccentric muscle strength and CoD speed performance. In addition, we summarize the few available studies on the effects of strength training with accentuated eccentric muscle actions on CoD speed performance in athletic populations. Finally, we propose strength training with accentuated eccentric muscle actions as a promising element in strength and conditioning programs of sports with high CoD speed demands. Our findings from five cross-sectional studies revealed statistically significant moderate- to large-sized correlations (r = 0.45-0.89) between measures of eccentric muscle strength and CoD speed performance in athletic populations. The identified three intervention studies were of limited methodological quality and reported small- to large-sized effects (d = 0.46-1.31) of strength training with accentuated eccentric muscle actions on CoD speed performance in athletes. With reference to the available but preliminary literature and from a performance-related point of view, we recommend strength and conditioning coaches to include strength training with accentuated eccentric muscle actions in training routines of sports with high CoD speed demands (e.g., soccer, handball, basketball, hockey) to

Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

Science.gov (United States)

Croisier, J L; Camus, G; Deby-Dupont, G; Bertrand, F; Lhermerout, C; Crielaard, J M; Juchmès-Ferir, A; Deby, C; Albert, A; Lamy, M

1996-01-01

To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle

Patellar tendon load in different types of eccentric squats.

Science.gov (United States)

Frohm, A; Halvorsen, K; Thorstensson, A

2007-07-01

Differences in mechanical loading of the patellar tendon have been suggested as a reason for varying effects in rehabilitation of patellar tendinopathy using different eccentric squat exercises and devices. The aim was to characterize the magnitude and pattern of mechanical load at the knee and on the patellar tendon during four types of eccentric squat. Subjects performed squats with a submaximal free weight and with maximal effort in a device for eccentric overloading (Bromsman), on a decline board and horizontal surface. Kinematics was recorded with a motion-capture system, reaction forces with force plates, and electromyography from three leg muscles with surface electrodes. Inverse dynamics was used to calculate knee joint kinetics. Eccentric work, mean and peak patellar tendon force, and angle at peak force were greater (25-30%) for squats on decline board compared to horizontal surface with free weight, but not in Bromsman. Higher knee load forces (60-80%), but not work, were observed with Bromsman than free weight. Angular excursions at the knee and ankle were larger with decline board, particularly with free weight, and smaller in Bromsman than with free weight. Mean electromyography was greater on a decline board for gastrocnemius (13%) and vastus medialis (6%) with free weight, but in Bromsman only for gastrocnemius (7%). The results demonstrated clear differences in the biomechanical loading on the knee during different squat exercises. Quantification of such differences provides information that could be used to explain differences in rehabilitation effects as well as in designing more optimal rehabilitation exercises for patellar tendinopathy.

Effect of Eccentricity of Load on Critical Force of Thin-Walled Columns CFRP

Directory of Open Access Journals (Sweden)

Pawel Wysmulski

2017-09-01

Full Text Available The subject of study was a thin-walled C-section made of carbon fiber reinforced polymer (CFRP. Column was subjected to eccentric compression in the established direction. In the computer simulation, the boundary conditions were assumed in the form of articulated support of the sections of the column. Particular studies included an analysis of the effects of eccentricity on the critical force value. The research was conducted using two independent research methods: numerical and experimental. Numerical simulations were done using the finite element method using the advanced system Abaqus®. The high sensitivity of the critical force value corresponding to the local buckling of the channel section to the load eccentricity was demonstrated.

Virtual Proprioception for eccentric training.

Science.gov (United States)

LeMoyne, Robert; Mastroianni, Timothy

2017-07-01

Wireless inertial sensors enable quantified feedback, which can be applied to evaluate the efficacy of therapy and rehabilitation. In particular eccentric training promotes a beneficial rehabilitation and strength training strategy. Virtual Proprioception for eccentric training applies real-time feedback from a wireless gyroscope platform enabled through a software application for a smartphone. Virtual Proprioception for eccentric training is applied to the eccentric phase of a biceps brachii strength training and contrasted to a biceps brachii strength training scenario without feedback. During the operation of Virtual Proprioception for eccentric training the intent is to not exceed a prescribed gyroscope signal threshold based on the real-time presentation of the gyroscope signal, in order to promote the eccentric aspect of the strength training endeavor. The experimental trial data is transmitted wireless through connectivity to the Internet as an email attachment for remote post-processing. A feature set is derived from the gyroscope signal for machine learning classification of the two scenarios of Virtual Proprioception real-time feedback for eccentric training and eccentric training without feedback. Considerable classification accuracy is achieved through the application of a multilayer perceptron neural network for distinguishing between the Virtual Proprioception real-time feedback for eccentric training and eccentric training without feedback.

Joint dynamics and intra-subject variability during countermovement jumps in children and adults

DEFF Research Database (Denmark)

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

2016-01-01

The present study investigated lower limb joint work, lower limb joint energy transport and intra-subject variation of the joint dynamics during countermovement jumps in children and adults. Twelve healthy men and eleven healthy boys performed ten maximal countermovement jumps. Three dimensional...... kinematics and kinetics were recorded in synchrony. Hip, knee and ankle joint eccentric and concentric work, joint energy transfer, intra-subject variation of joint moment, joint power and joint moment components were calculated. The children had lower eccentric and concentric hip work and lower eccentric...... work, hip joint moment and hip and knee joint power. Higher intra-subject variation was observed in horizontal joint reaction force components for the children and higher intra-subject variation in the segment angular inertia components was observed for the adults. The joint dynamics of children during...

Effects of adding a weekly eccentric-overload training session on strength and athletic performance in team-handball players.

Science.gov (United States)

Sabido, Rafael; Hernández-Davó, Jose Luis; Botella, Javier; Navarro, Angel; Tous-Fajardo, Julio

2017-06-01

To investigate the influence of adding a weekly eccentric-overload training (EOT) session in several athletic performance's tests, 18 team-handball players were assigned either to an EOT (n = 11) or a Control (n = 7) group. Both groups continued to perform the same habitual strength training, but the EOT group added one session/week during a 7-week training programme consisting of four sets of eight repetitions for the bilateral half-squat and unilateral lunge exercises. The test battery included handball throwing velocity, maximum dynamic strength (1RM), countermovement jump (CMJ), 20 m sprint, triple hop for distance, and eccentric/concentric power in both the half-squat and lunge exercises. Data were analysed using magnitude-based inferences. Both groups improved their 1RM in the half squat, 20 m sprint time, and CMJ performance to a similar extent, but the EOT group showed a beneficial effect for both right [(42/58/0), possibly positive] and left [(99/1/0), very likely positive] triple hop for distance performance. In addition, the EOT group showed greater power output improvements in both eccentric and concentric phases of the half-squat (difference in percent of change ranging from 6.5% to 22.0%) and lunge exercises (difference in per cent of change ranging from 13.1% to 24.9%). Nevertheless, no group showed changes in handball throwing velocity. Selected variables related to team-handball performance (i.e. functional jumping performance, power output) can be improved by adding a single EOT session per week, highlighting the usefulness of this low-volume/high-intensity training when aiming at optimizing dynamic athletic performance.

Forward lunge: a training study of eccentric exercises of the lower limbs.

Science.gov (United States)

Jönhagen, Sven; Ackermann, Paul; Saartok, Tönu

2009-05-01

A few studies have shown that eccentric exercise is effective for prevention and treatment of muscle injuries. Most earlier studies on eccentric exercises have used training with advanced equipment. Forward lunges are considered eccentric exercises, and they may be performed without any equipment. These exercises are commonly used by sprint runners. We performed a prospective, randomized, 6-week training study comparing the effects of walking or jumping forward lunges on hamstring and quadriceps strength and function. Thirty-two soccer players were included in the study. The forward lunge training was done as an addition to ordinary soccer training twice a week for 6 weeks. The outcome was measured by the maximal hamstring and quadriceps strength tests and by functional tests with 1-leg hop tests and 30-m sprint runs. Overall muscle pain was evaluated using a visual analogue scale score, and local pain was estimated with an algometer. Whereas the walking lunge improved hamstring strength, the jumping lunge resulted in sprint running improvements. Algometer testing showed a general increase in the pain detection thresholds of all subjects, including the controls. Thus, precautions should be taken when algometers are used for temporal studies of pain. Walking and jumping forward lunges can be used for improving hamstring strength and running speed in young soccer player. The findings may have relevance when designing protocols for prevention and rehabilitation of muscle injuries.

The effect of different accentuated eccentric load levels in eccentric-concentric loading contractions on acute neuromuscular, growth hormone and blood lactate responses during a hypertrophic protocol

OpenAIRE

Ojasto, Timo

2007-01-01

When accentuated load is applied during the eccentric (ECC) phase of eccentric-concentric (ECC-CON) contractions, it is defined as dynamic accentuated external resistance (DAER) exercise. This study monitored acute neuromuscular responses, growth hormone (GH) and blood lactate (La) concentrations to find out the most efficient ECC-CON loading strategy for muscle hypertrophy by employing various DAER resistances in the bench-press. Male subjects (age=32.4±4.3years, n=11) were assigned as subje...

Eccentric Training for Tendon Healing After Acute Lesion: A Rat Model.

Science.gov (United States)

Kaux, Jean-François; Libertiaux, Vincent; Leprince, Pierre; Fillet, Marianne; Denoel, Vincent; Wyss, Clémence; Lecut, Christelle; Gothot, André; Le Goff, Caroline; Croisier, Jean-Louis; Crielaard, Jean-Michel; Drion, Pierre

2017-05-01

The tendon is a dynamic entity that remodels permanently. Platelet-rich plasma (PRP) injection has been shown to have a beneficial effect on tendon healing after lesion in rats. Furthermore, eccentric exercise seems to improve the mechanical quality of the tendon. A combination of PRP injection and eccentric training might be more effective than either treatment alone. Controlled laboratory study. Adult male rats were anesthetized, an incision was performed in the middle of their left patellar tendon and an injection of physiological fluid (PF) or homologous PRP was randomly made at the lesion level. The rats were then divided into 2 groups: the eccentric group, undergoing eccentric training 3 times a week, and the untrained group, without any training. Thus, 4 groups were compared. After 5 weeks, the tendons were removed and their ultimate tensile strength and energy were measured. Tendons were frozen for proteomic analyses when all biomechanical tests were completed. Statistical analysis was performed with linear mixed effect models. No significant difference was found between the treatments using PF injection or PRP injection alone. However, the value of the ultimate tensile force at rupture was increased by 4.5 N (108% of control, P = .006) when eccentric training was performed. An intragroup analysis revealed that eccentric training significantly improved the ultimate force values for the PRP group. Proteomic analysis revealed that eccentric training led to an increase in abundance of several cytoskeletal proteins in the PF group, while a decrease in abundance of enzymes of the glycolytic pathway occurred in the PRP-treated groups, indicating that this treatment might redirect the exercise-driven metabolic plasticity of the tendon. Eccentric training altered the metabolic plasticity of tendon and led to an improvement of injured tendon resistance regardless of the treatment injected (PF or PRP). This study demonstrates the necessity of eccentric rehabilitation

The magnitude of muscle strain does not influence serial sarcomere number adaptations following eccentric exercise.

Science.gov (United States)

Butterfield, Timothy A; Herzog, Walter

2006-02-01

It is generally accepted that eccentric exercise, when performed by a muscle that is unaccustomed to that type of contraction, results in a delayed onset of muscle soreness (DOMS). A prolonged exposure to eccentric exercise leads to the disappearance of the signs and symptoms associated with DOMS, which has been referred to as the repeated bout effect (RBE). Although the mechanisms underlying the RBE remain unclear, several mechanisms have been proposed, including the serial sarcomere number addition following exercise induced muscle damage. In the traditional DOMS and RBE protocols, muscle injury has been treated as a global parameter, with muscle force and strain assumed to be uniform throughout the muscle. To assess the effects of muscle-tendon unit strain, fiber strain, torque and injury on serial sarcomere number adaptations, three groups of New Zealand White (NZW) rabbits were subjected to chronic repetitive eccentric exercise bouts of the ankle dorsiflexors for 6 weeks. These eccentric exercise protocols consisted of identical muscle tendon unit (MTU) strain, but other mechanical factors were systematically altered. Following chronic eccentric exercise, serial sarcomere number adaptations were not identical between the three eccentric exercise protocols, and serial sarcomere number adaptations were not uniform across all regions of the muscle. Peak torque and relaxation fiber strain were the best predictors of serial sarcomere number across all three protocols. Therefore, MTU strain does not appear to be the primary cause for sarcomerogenesis, and differential adaptations within the muscle may be explained by the nonuniform architecture of the muscle, resulting in differential local fiber strains.

Eccentric exercise training in patients with chronic obstructive pulmonary disease.

NARCIS (Netherlands)

Rooyackers, J.M.; Berkeljon, D.A.; Folgering, H.T.M.

2003-01-01

The oxygen cost of eccentric exercise is lower than that of concentric exercise at similar work-loads. In this study, the response to eccentric cycle exercise training (EET) in addition to general exercise training (GET) on exercise performance and quality of life was investigated in 24 patients

Is eccentric exercise an effective treatment for lateral epicondylitis? A systematic review.

Science.gov (United States)

Cullinane, Frances L; Boocock, Mark G; Trevelyan, Fiona C

2014-01-01

To establish the effectiveness of eccentric exercise as a treatment intervention for lateral epicondylitis. ProQuest, Medline via EBSCO, AMED, Scopus, Web of Science, CINAHL. A systematic review was undertaken to identify randomized and controlled clinical trials incorporating eccentric exercise as a treatment for patients diagnosed with lateral epicondylitis. Studies were included if: they incorporated eccentric exercise, either in isolation or as part of a multimodal treatment protocol; they assessed at least one functional or disability outcome measure; and the patients had undergone diagnostic testing. The methodological quality of each study was assessed using the Modified Cochrane Musculoskeletal Injuries Group score sheet. Twelve studies met the inclusion criteria. Three were deemed 'high' quality, seven were 'medium' quality, and two were 'low' quality. Eight of the studies were randomized trials investigating a total of 334 subjects. Following treatment, all groups inclusive of eccentric exercise reported decreased pain and improved function and grip strength from baseline. Seven studies reported improvements in pain, function, and/or grip strength for therapy treatments inclusive of eccentric exercise when compared with those excluding eccentric exercise. Only one low-quality study investigated the isolated effects of eccentric exercise for treating lateral epicondylitis and found no significant improvements in pain when compared with other treatments. The majority of consistent findings support the inclusion of eccentric exercise as part of a multimodal therapy programme for improved outcomes in patients with lateral epicondylitis.

Decline eccentric squats increases patellar tendon loading compared to standard eccentric squats

DEFF Research Database (Denmark)

Kongsgaard, M; Aagaard, P; Roikjaer, S

2006-01-01

Recent studies have shown excellent clinical results using eccentric squat training on a 25 degrees decline board to treat patellar tendinopathy. It remains unknown why therapeutic management of patellar tendinopathy using decline eccentric squats offer superior clinical efficacy compared...

Eccentricity dimension of the Dimensional Clinical Personality Inventory: Review and psychometric properties

Directory of Open Access Journals (Sweden)

Lucas de Francisco Carvalho

Full Text Available Abstract We aimed to review of the Eccentricity dimension of the Dimensional Clinical Personality Inventory (IDCP, through two steps. The first one focused on developing new items and the second on testing the psychometric properties in a sample of 225 subjects (70.1% females, aging between 18 and 66 years, mostly undergraduate students (58.9%. The subjects answered the IDCP, and the Brazilian versions of the NEO-PI-R, PID-5 and MIS. The first step resulted in 42 items, which 22 were new. The second step resulted in a composite of 18 items, pooled in six interpretable factors, as Interpersonal detachment, Eccentric style, Paranormality, Persecutory style, Depersonalization and Emotional inexpressiveness, with internal consistency coefficients of .85 for the total score, and between .60 and .82 for the factors. The correlations between instruments revealed consistent and expected relations. The data suggested adequacy of the new Eccentricity dimension of IDCP.

Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running

DEFF Research Database (Denmark)

Oliveira, Anderson S. C.; Caputo, Fabrizio; Aagaard, Per

2013-01-01

session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180° s(-1), or served as controls (n...... damages. However, IERT may not avoid reductions in explosive muscle actions. In turn, this may allow more intense training sessions to be performed, facilitating the adaptive response to running training.......The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective...

Achilles tendinopathy modulates force frequency characteristics of eccentric exercise.

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Grigg, Nicole L; Wearing, Scott C; O'Toole, John M; Smeathers, James E

2013-03-01

Previous research has demonstrated that ground reaction force (GRF) recorded during eccentric ankle exercise is characterized by greater power in the 8- to 12-Hz bandwidth when compared with that recorded during concentric ankle exercise. Subsequently, it was suggested that vibrations in this bandwidth may underpin the beneficial effect of eccentric loading in tendon repair. However, this observation has been made only in individuals without Achilles tendinopathy. This research compared the force frequency characteristics of eccentric and concentric exercises in individuals with and without Achilles tendinopathy. Eleven male adults with unilateral midportion Achilles tendinopathy and nine control male adults without tendinopathy participated in the research. Kinematics and GRF were recorded while the participants performed a common eccentric rehabilitation exercise protocol and a concentric equivalent. Ankle joint kinematics and the frequency power spectrum of the resultant GRF were calculated. Eccentric exercise was characterized by a significantly greater proportion of spectral power between 4.5 and 11.5 Hz when compared with concentric exercise. There were no significant differences between limbs in the force frequency characteristics of concentric exercise. Eccentric exercise, in contrast, was defined by a shift in the power spectrum of the symptomatic limb, resulting in a second spectral peak at 9 Hz, rather than 10 Hz in the control limb. Compared with healthy tendon, Achilles tendinopathy was characterized by lower frequency vibrations during eccentric rehabilitation exercises. This finding may be associated with changes in neuromuscular activation and tendon stiffness that have been shown to occur with tendinopathy and provides a possible rationale for the previous observation of a different biochemical response to eccentric exercise in healthy and injured Achilles tendons.

The time course of short-term hypertrophy in the absence of eccentric muscle damage.

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Stock, Matt S; Mota, Jacob A; DeFranco, Ryan N; Grue, Katherine A; Jacobo, A Unique; Chung, Eunhee; Moon, Jordan R; DeFreitas, Jason M; Beck, Travis W

2017-05-01

It has been proposed that the increase in skeletal muscle mass observed during the initial weeks of initiating a resistance training program is concomitant with eccentric muscle damage and edema. We examined the time course of muscle hypertrophy during 4 weeks of concentric-only resistance training. Thirteen untrained men performed unilateral concentric-only dumbbell curls and shoulder presses twice per week for 4 weeks. Sets of 8-12 repetitions were performed to failure, and training loads were increased during each session. Subjects consumed 500 ml of whole milk during training. Assessments of soreness, lean mass, echo intensity, muscle thickness, relaxed and flexed arm circumference, and isokinetic strength were performed every 72 or 96 h. Soreness, echo intensity, relaxed circumference, and peak torque data did not significantly change. Significant increases in lean mass, muscle thickness, and flexed circumference were observed within seven training sessions. Lean mass was elevated at tests #7 (+109.3 g, p = .002) and #8 (+116.1 g, p = .035), with eight different subjects showing changes above the minimal difference of 139.1 g. Muscle thickness was elevated at tests #6 (+0.23 cm, p = .004), #7 (+0.31 cm, p hypertrophy may occur in the absence of eccentric muscle damage within seven training sessions.

Eccentric, nonspinning, inspiral, Gaussian-process merger approximant for the detection and characterization of eccentric binary black hole mergers

Science.gov (United States)

Huerta, E. A.; Moore, C. J.; Kumar, Prayush; George, Daniel; Chua, Alvin J. K.; Haas, Roland; Wessel, Erik; Johnson, Daniel; Glennon, Derek; Rebei, Adam; Holgado, A. Miguel; Gair, Jonathan R.; Pfeiffer, Harald P.

2018-01-01

We present ENIGMA, a time domain, inspiral-merger-ringdown waveform model that describes nonspinning binary black holes systems that evolve on moderately eccentric orbits. The inspiral evolution is described using a consistent combination of post-Newtonian theory, self-force and black hole perturbation theory. Assuming eccentric binaries that circularize prior to coalescence, we smoothly match the eccentric inspiral with a stand-alone, quasicircular merger, which is constructed using machine learning algorithms that are trained with quasicircular numerical relativity waveforms. We show that ENIGMA reproduces with excellent accuracy the dynamics of quasicircular compact binaries. We validate ENIGMA using a set of Einstein Toolkit eccentric numerical relativity waveforms, which describe eccentric binary black hole mergers with mass-ratios between 1 ≤q ≤5.5 , and eccentricities e0≲0.2 ten orbits before merger. We use this model to explore in detail the physics that can be extracted with moderately eccentric, nonspinning binary black hole mergers. In particular, we use ENIGMA to show that the gravitational wave transients GW150914, GW151226, GW170104, GW170814 and GW170608 can be effectively recovered with spinning, quasicircular templates if the eccentricity of these events at a gravitational wave frequency of 10 Hz satisfies e0≤{0.175 ,0.125 ,0.175 ,0.175 ,0.125 }, respectively. We show that if these systems have eccentricities e0˜0.1 at a gravitational wave frequency of 10 Hz, they can be misclassified as quasicircular binaries due to parameter space degeneracies between eccentricity and spin corrections. Using our catalog of eccentric numerical relativity simulations, we discuss the importance of including higher-order waveform multipoles in gravitational wave searches of eccentric binary black hole mergers.

The Effect of Taurine on the Recovery from Eccentric Exercise-Induced Muscle Damage in Males

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Yanita McLeay

2017-10-01

Full Text Available Eccentric exercise is known to bring about microstructural damage to muscle, initiating an inflammatory cascade involving various reactive oxygen species. This, in turn, can significantly impair physical performance over subsequent days. Taurine, a powerful endogenous antioxidant, has previously been shown to have a beneficial effect on muscle damage markers and recovery when taken for a few days to several weeks prior to eccentric exercise. However, to date no studies have looked at the effects of supplementing over the days following eccentric exercise on performance recovery. Thus, this study aimed to determine whether supplementing with taurine over three days following eccentric exercise attenuated the rise in serum creatine kinase and improved performance recovery in males. In a blinded, randomized, crossover design, ten recreationally-fit male participants completed 60 eccentric contractions of the biceps brachii muscle at maximal effort. Following this, participants were supplemented with 0.1 g∙kg−1 body weight∙day−1 of either taurine or rice flour in capsules. Over the next three mornings participants underwent blood tests for the analysis of the muscle damage marker creatine kinase and carried out performance measures on the isokinetic dynamometer. They also continued to consume the capsules in the morning and evening. The entire protocol was repeated two weeks later on the alternate arm and supplement. Significant decreases were seen in all performance measures from pre- to 24-h post-eccentric exercise (p < 0.001 for both taurine and placebo, indicating the attainment of muscle damage. Significant treatment effects were observed only for peak eccentric torque (p < 0.05. No significant time × treatment effects were observed (all p > 0.05. Serum creatine kinase levels did not significantly differ over time for either treatments, nor between treatments (p > 0.05. These findings suggest that taurine supplementation taken twice

Therapeutic potential of eccentric exercises for age-related muscle atrophy

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Jae-Young Lim

2016-09-01

Full Text Available Recent studies have focused on evidence-based interventions to prevent mobility decline and enhance physical performance in older adults. Several modalities, in addition to traditional strengthening programs, have been designed to manage age-related functional decline more effectively. In this study, we reviewed the current relevant literatures to assess the therapeutic potential of eccentric exercises for age-related muscle atrophy (sarcopenia. Age-related changes in human skeletal muscle, and their relationship with physical performance, are discussed with reference to in vitro physiologic and human biomechanics studies. An overview of issues relevant to sarcopenia is provided in the context of the recent consensus on the diagnosis and management of the condition. A decline in mobility among the aging population is closely linked with changes in the muscle force–velocity relationship. Interventions based specifically on increasing velocity and eccentric strength can improve function more effectively compared with traditional strengthening programs. Eccentric strengthening programs are introduced as a specific method for improving both muscle force and velocity. To be more effective, exercise interventions for older adults should focus on enhancing the muscle force–velocity relationship. Exercises that can be performed easily, and that utilize eccentric strength (which is relatively spared during the aging process, are needed to improve both muscle force and velocity.

The Eccentric Behavior of Nearly Frozen Orbits

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Sweetser, Theodore H.; Vincent, Mark A.

2013-01-01

Frozen orbits are orbits which have only short-period changes in their mean eccentricity and argument of periapse, so that they basically keep a fixed orientation within their plane of motion. Nearly frozen orbits are those whose eccentricity and argument of periapse have values close to those of a frozen orbit. We call them "nearly" frozen because their eccentricity vector (a vector whose polar coordinates are eccentricity and argument of periapse) will stay within a bounded distance from the frozen orbit eccentricity vector, circulating around it over time. For highly inclined orbits around the Earth, this distance is effectively constant over time. Furthermore, frozen orbit eccentricity values are low enough that these orbits are essentially eccentric (i.e., off center) circles, so that nearly frozen orbits around Earth are bounded above and below by frozen orbits.

HAMSTRING ARCHITECTURAL AND FUNCTIONAL ADAPTATIONS FOLLOWING LONG VS. SHORT MUSCLE LENGTH ECCENTRIC TRAINING

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Kenny Guex

2016-08-01

Full Text Available Most common preventive eccentric-based exercises, such as Nordic hamstring do not include any hip flexion. So, the elongation stress reached is lower than during the late swing phase of sprinting. The aim of this study was to assess the evolution of hamstring architectural (fascicle length and pennation angle and functional (concentric and eccentric optimum angles and concentric and eccentric peak torques parameters following a 3-week eccentric resistance program performed at long (LML versus short muscle length (SML. Both groups performed eight sessions of 3-5x8 slow maximal eccentric knee extensions on an isokinetic dynamometer: the SML group at 0° and the LML group at 80° of hip flexion. Architectural parameters were measured using ultrasound imaging and functional parameters using the isokinetic dynamometer. The fascicle length increased by 4.9% (p<0.01, medium effect size in the SML and by 9.3% (p<0.001, large effect size in the LML group. The pennation angle did not change (p=0.83 in the SML and tended to decrease by 0.7° (p=0.09, small effect size in the LML group. The concentric optimum angle tended to decrease by 8.8° (p=0.09, medium effect size in the SML and by 17.3° (p<0.01, large effect size in the LML group. The eccentric optimum angle did not change (p=0.19, small effect size in the SML and tended to decrease by 10.7° (p=0.06, medium effect size in the LML group. The concentric peak torque did not change in the SML (p=0.37 and the LML (p=0.23 groups, whereas eccentric peak torque increased by 12.9% (p<0.01, small effect size and 17.9% (p<0.001, small effect size in the SML and the LML group, respectively. No group-by-time interaction was found for any parameters. A correlation was found between the training-induced change in fascicle length and the change in concentric optimum angle (r=-0.57, p<0.01. These results suggest that performing eccentric exercises lead to several architectural and functional adaptations. However

Creep and cracking of concrete hinges: insight from centric and eccentric compression experiments.

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Schlappal, Thomas; Schweigler, Michael; Gmainer, Susanne; Peyerl, Martin; Pichler, Bernhard

2017-01-01

Existing design guidelines for concrete hinges consider bending-induced tensile cracking, but the structural behavior is oversimplified to be time-independent. This is the motivation to study creep and bending-induced tensile cracking of initially monolithic concrete hinges systematically. Material tests on plain concrete specimens and structural tests on marginally reinforced concrete hinges are performed. The experiments characterize material and structural creep under centric compression as well as bending-induced tensile cracking and the interaction between creep and cracking of concrete hinges. As for the latter two aims, three nominally identical concrete hinges are subjected to short-term and to longer-term eccentric compression tests. Obtained material and structural creep functions referring to centric compression are found to be very similar. The structural creep activity under eccentric compression is significantly larger because of the interaction between creep and cracking, i.e. bending-induced cracks progressively open and propagate under sustained eccentric loading. As for concrete hinges in frame-like integral bridge construction, it is concluded (i) that realistic simulation of variable loads requires consideration of the here-studied time-dependent behavior and (ii) that permanent compressive normal forces shall be limited by 45% of the ultimate load carrying capacity, in order to avoid damage of concrete hinges under sustained loading.

Development of online cable eccentricity detection system based on X-ray CCD

International Nuclear Information System (INIS)

Chen Jianzhen; Li Bin; Wei Kaixia; Guo Lanying; Qu Guopu

2008-01-01

An improved technology of online cable eccentricity detection, based on X-ray CCD, greatly improves the measuring precision and the responding speed. The theory of eccentricity measuring based on X-ray CCD, and the structure of an apparatus are described. The apparatus is composed of scanning drive subsystem, X-ray generation components, data acquiring subsystem and high performance computer system. The measuring results are also presented. The features of this cable eccentricity detection technology are compared with the features of other technologies. (authors)

Muscle damage and repeated bout effect induced by enhanced eccentric squats.

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Coratella, Giuseppe; Chemello, Alessandro; Schena, Federico

2016-12-01

Muscle damage and repeated bout effect have been studied after pure eccentric-only exercise. The aim of this study was to evaluate muscle damage and repeated bout effect induced by enhanced eccentric squat exercise using flywheel device. Thirteen healthy males volunteered for this study. Creatine kinase blood activity (CK), quadriceps isometric peak torque and muscle soreness were used as markers of muscle damage. The dependent parameters were measured at baseline, immediately after and each day up to 96 hours after the exercise session. The intervention consisted of 100 repetitions of enhanced eccentric squat exercise using flywheel device. The same protocol was repeated after 4 weeks. After the first bout, CK and muscle soreness were significantly greater (P0.05), while isometric peak torque and muscle soreness returned to values similar to baseline after respectively 48 and 72 hours. All muscle damage markers were significantly lower after second compared to first bout. The enhanced eccentric exercise induced symptoms of muscle damage up to 96 hours. However, it provided muscle protection after the second bout, performed four weeks later. Although it was not eccentric-only exercise, the enhancement of eccentric phase provided muscle protection.

EFFICACY OF CYRIAX PHYSIOTHERAPY VERSUS ECCENTRIC STRENGTHENING AND STRETCHING EXERCISES IN CHRONIC LATERAL EPICONDYLITIS PATIENTS

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Madhusmita Koch

2015-10-01

Full Text Available Background: Lateral Epicondylitis is the most common lesion of the elbow, affecting the tendinous origin of the wrist extensors. Although conservative treatment of this condition has been the subject of numerous studies, there is no agreement as to the most effective management strategy. Therefore, this study was designed to compare the efficacy of Cyriax physiotherapy Versus Eccentric Strengthening and Stretching exercises in reducing the pain and improving the grip strength and functional status of the affected extremity in chronic lateral epicondylitis. Method: An experimental study design, 60 subjects meeting the inclusion criteria were selected for the study and were randomly assigned into two groups: Group A (N=30 received Cyriax Physiotherapy and Group B(N=30 received Eccentric strengthening and static stretching of Extensor Carpi Radialis Brevis. Low Level Laser Therapy was a common treatment for both the groups. After 4 weeks of treatment, assessment was performed using Visual Analogue Scale (VAS, Hand Held Dynamometer (HHD and Patient Rated Tennis Elbow Evaluation Questionnaire (PRTEE at 0 week and at the end of 4 weeks. Results: Data analysis revealed that there is no statistically significant difference between the groups in VAS, HHD and PRTEE scores i.e. average improvement post treatment in both the groups are equal, but within group comparisons showed significant improvements in both the groups. Conclusion: The efficacy of Cyriax Physiotherapy is equal to Eccentric Strengthening and Stretching Exercises in chronic lateral epicondylitis.

Introducing Earth's Orbital Eccentricity

Science.gov (United States)

Oostra, Benjamin

2015-01-01

Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

Eccentric exercise: acute and chronic effects on healthy and diseased tendons.

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Kjaer, Michael; Heinemeier, Katja M

2014-06-01

Eccentric exercise can influence tendon mechanical properties and matrix protein synthesis. mRNA for collagen and regulatory factors thereof are upregulated in animal tendons, independent of muscular contraction type, supporting the view that tendon, compared with skeletal muscle, is less sensitive to differences in type and/or amount of mechanical stimulus with regard to expression of collagen, regulatory factors for collagen, and cross-link regulators. In overused (tendinopathic) human tendon, eccentric exercise training has a beneficial effect, but the mechanism by which this is elicited is unknown, and slow concentric loading appears to have similar beneficial effects. It may be that tendinopathic regions, as long as they are subjected to a certain magnitude of load at a slow speed, independent of whether this is eccentric or concentric in nature, can reestablish their normal tendon fibril alignment and cell morphology. Copyright © 2014 the American Physiological Society.

Eccentric versus conventional exercise therapy in patients with rotator cuff tendinopathy: a randomized, single blinded, clinical trial.

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Dejaco, Beate; Habets, Bas; van Loon, Corné; van Grinsven, Susan; van Cingel, Robert

2017-07-01

To investigate the effectiveness of isolated eccentric versus conventional exercise therapy in patients with rotator cuff tendinopathy. Thirty-six patients with rotator cuff tendinopathy, diagnosed by an orthopaedic surgeon, were included and randomly allocated to an isolated eccentric exercise (EE) group (n = 20, mean age = 50.2 ± 10.8 years) or a conventional exercise (CG) group (n = 16, mean age = 48.6 ± 12.3 years). Both groups fulfilled a 12-week daily home-based exercise programme and received a total amount of nine treatment sessions. The Constant Murley score was used to evaluate both objective (e.g. range of motion and strength) and subjective measures (e.g. pain and activities of daily living). A visual analogue scale (VAS) was used to evaluate pain during daily activities. As secondary outcomes, shoulder range of motion and isometric abduction strength in 45° in the scapular plane were evaluated. All measurements were taken at baseline, at 6, 12 and 26 weeks. After 26 weeks, both groups showed a significant increase in the Constant Murley score and a significant decrease in VAS scores. No difference was found between the groups, for any of the evaluated outcome measures. A 12-week-isolated eccentric training programme of the rotator cuff is beneficial for shoulder function and pain after 26 weeks in patients with rotator cuff tendinopathy. However, it is no more beneficial than a conventional exercise programme for the rotator cuff and scapular muscles. Based on the results, clinicians should take into account that performing two eccentric exercises twice a day is as effective as performing six concentric/eccentric exercises once a day in patients with rotator cuff tendinopathy.

The Effects of Eccentric Contraction Duration on Muscle Strength, Power Production, Vertical Jump, and Soreness.

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Mike, Jonathan N; Cole, Nathan; Herrera, Chris; VanDusseldorp, Trisha; Kravitz, Len; Kerksick, Chad M

2017-03-01

Mike, JN, Cole, N, Herrera, C, VanDusseldorp, T, Kravitz, L, and Kerksick, CM. The effects of eccentric contraction duration on muscle strength, power production, vertical jump, and soreness. J Strength Cond Res 31(3): 773-786, 2017-Previous research has investigated the effects of either eccentric-only training or comparing eccentric and concentric exercise on changes related to strength and power expression, but no research to date has investigated the impact of altering the duration of either the concentric or the eccentric component on these parameters. Therefore, the purpose of this study was to assess the duration of eccentric (i.e., 2-second, 4-second vs. 6-second) muscle contractions and their effect on muscle strength, power production, vertical jump, and soreness using a plate-loaded barbell Smith squat exercise. Thirty college-aged men (23 ± 3.5 years, 178 ± 6.8 cm, 82 ± 12 kg, and 11.6 ± 5.1% fat) with 3.0 ± 1.0 years of resistance training experience and training frequency of 4.3 ± 0.9 days per week were randomized and assigned to 1 of 3 eccentric training groups that incorporated different patterns of contraction. For every repetition, all 3 groups used 2-second concentric contractions and paused for 1 second between the concentric and eccentric phases. The control group (2S) used 2-second eccentric contractions, whereas the 4S group performed 4-second eccentric contractions and the 6S group performed 6-second eccentric contractions. All repetitions were completed using the barbell Smith squat exercise. All participants completed a 4-week training protocol that required them to complete 2 workouts per week using their prescribed contraction routine for 4 sets of 6 repetitions at an intensity of 80-85% one repetition maximum (1RM). For all performance data, significant group × time (G × T) interaction effects were found for average power production across all 3 sets of a squat jump protocol (p = 0.04) while vertical jump did not reach

Motor unit activity after eccentric exercise and muscle damage in humans.

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Semmler, J G

2014-04-01

It is well known that unaccustomed eccentric exercise leads to muscle damage and soreness, which can produce long-lasting effects on muscle function. How this muscle damage influences muscle activation is poorly understood. The purpose of this brief review is to highlight the effect of eccentric exercise on the activation of muscle by the nervous system, by examining the change in motor unit activity obtained from surface electromyography (EMG) and intramuscular recordings. Previous research shows that eccentric exercise produces unusual changes in the EMG–force relation that influences motor performance during isometric, shortening and lengthening muscle contractions and during fatiguing tasks. When examining the effect of eccentric exercise at the single motor unit level, there are substantial changes in recruitment thresholds, discharge rates, motor unit conduction velocities and synchronization, which can last for up to 1 week after eccentric exercise. Examining the time course of these changes suggests that the increased submaximal EMG after eccentric exercise most likely occurs through a decrease in motor unit conduction velocity and an increase in motor unit activity related to antagonist muscle coactivation and low-frequency fatigue. Furthermore, there is a commonly held view that eccentric exercise produces preferential damage to high-threshold motor units, but the evidence for this in humans is limited. Further research is needed to establish whether there is preferential damage to high-threshold motor units after eccentric exercise in humans, preferably by linking changes in motor unit activity with estimates of motor unit size using selective intramuscular recording techniques.

Preconditioning by light-load eccentric exercise is equally effective as low-level laser therapy in attenuating exercise-induced muscle damage in collegiate men

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Nausheen S

2017-09-01

Full Text Available Samar Nausheen,1 Jamal Ali Moiz,1 Shahid Raza,1 Mohammad Yakub Shareef,2 Shahnawaz Anwer,3,4 Ahmad H Alghadir3 1Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India; 2Faculty of Dentistry, Jamia Millia Islamia, New Delhi, India; 3Rehabilitation Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia; 4Dr. D. Y. Patil College of Physiotherapy, Dr. D. Y. Patil Vidyapeeth, Pune, India Background/objective: Previous studies have already reported an independent effect of light-load eccentric exercise (10% eccentric exercise contraction [EEC] and low-level laser therapy (LLLT as a protective measure against more strenuous eccentric exercise. However, the difference between these two interventions is largely unknown. Therefore, the present study aimed to compare the preconditioning effect of 10% EEC vs. LLLT on subjective, physiological, and biochemical markers of muscle damage in elbow flexors in collegiate men.Methods: All 36 enrolled subjects were randomly assigned to either 10% EEC or LLLT group. Subjects in 10% EEC group performed 30 repetitions of an eccentric exercise with 10% maximal voluntary contraction strength 2 days prior to maximal eccentric exercise bout, whereas subjects in LLLT group were given LLLT. All the indirect markers of muscle damage were measured pre-exercise and at 24, 48, and 72 hours after the exercise-induced muscle damage protocol.Results: The muscle soreness was reduced in both groups (p = 0.024; however, soreness was attenuated more in LLLT group at 48 hours (33.5 vs. 42.7, p = 0.004. There was no significant difference between the effect of 10% EEC and LLLT groups on other markers of muscle damage like a maximum voluntary isometric contraction (p = 0.47, range of motion (p = 0.16, upper arm circumference (p = 0.70, creatine kinase (p = 0.42, and lactate dehydrogenase (p = 0.08. Within-group analysis showed both interventions provided

The Effect of Exercise-Induced Muscle Damage After a Bout of Accentuated Eccentric Load Drop Jumps and the Repeated Bout Effect.

Science.gov (United States)

Bridgeman, Lee A; Gill, Nicholas D; Dulson, Deborah K; McGuigan, Michael R

2017-02-01

Bridgeman, LA, Gill, ND, Dulson, DK, and McGuigan, MR. The effect of exercise induced muscle damage after a bout of accentuated eccentric load drop jumps and the repeated bout effect. J Strength Cond Res 31(2): 386-394, 2017-Although previous studies have investigated exercise-induced muscle damage (EIMD) after a bout of unloaded drop jumps (DJs), none have investigated the effects of accentuated eccentric load (AEL) DJs on EIMD. The purpose of this study was to investigate the effects of 30 and 50 AEL DJs on strength, jump performance, muscle soreness, and blood markers. Eight resistance trained athletes participated in this study. In week 1, baseline countermovement jump (CMJ), squat jump (SJ), concentric and eccentric peak force (PF), creatine kinase, and muscle soreness were assessed. Subjects then completed 30 AEL DJs and baseline measures were retested immediately postintervention, 1, 24, and 48 hours later. Two weeks later, the subjects completed the same protocol with an increase in AEL DJ volume (50). Subjects' SJ height was reduced in week 1 compared with week 3, postintervention, 1, 24, and 48 hours later (ES = -0.34, -0.44, -0.38, and -0.40). Subjects' CMJ height was reduced in week 1 compared with week 3, postintervention, 1, and 24 hours later (ES = -0.37, -0.29, and -0.39). Concentric PF was reduced in week 1 compared with week 3, postintervention and 24 and 48 hours later (ES = -0.02, -0.23, and -0.32). Eccentric PF was reduced in week 1 compared with week 3, postintervention, 24, and 48 hours later (ES = -0.24, -0.16, and -0.50). In this sample, 30 AEL DJs attenuated the effects of EIMD following which 50 AEL DJs completed 2 weeks later.

A new kinematical definition of orbital eccentricity

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Ninković S.

2009-01-01

Full Text Available A new concept of orbital eccentricity is given. The dimensionless quantities proposed in the present paper to serve as orbital eccentricities have a kinematical nature. The purpose is to use them in describing the motion for the case of three-dimensional orbits. A comparison done for nearly planar orbits shows that the values of the eccentricities proposed here do not differ significantly from those corresponding to the eccentricities of geometric nature usually applied.

Effects of concentric vs eccentric loading on cardiovascular ...

African Journals Online (AJOL)

Effects of concentric vs eccentric loading on cardiovascular variables and ECG. Madan Bhavna1*, Sarika, Sandhu J.S1. 1. Department of Sports Medicine and Physiotherapy Guru Nanak Dev University; ..... psychological and performance.

Vitamin D2 Supplementation Amplifies Eccentric Exercise-Induced Muscle Damage in NASCAR Pit Crew Athletes

Science.gov (United States)

Nieman, David C.; Gillitt, Nicholas D.; Shanely, R. Andrew; Dew, Dustin; Meaney, Mary Pat; Luo, Beibei

2013-01-01

This study determined if 6-weeks vitamin D2 supplementation (vitD2, 3800 IU/day) had an influence on muscle function, eccentric exercise-induced muscle damage (EIMD), and delayed onset of muscle soreness (DOMS) in National Association for Stock Car Auto Racing (NASCAR) NASCAR pit crew athletes. Subjects were randomized to vitD2 (n = 13) and placebo (n = 15), and ingested supplements (double-blind) for six weeks. Blood samples were collected and muscle function tests conducted pre- and post-study (leg-back and hand grip dynamometer strength tests, body weight bench press to exhaustion, vertical jump, 30-s Wingate test). Post-study, subjects engaged in 90 min eccentric-based exercise, with blood samples and DOMS ratings obtained immediately after and 1- and 2-days post-exercise. Six weeks vitD2 increased serum 25(OH)D2 456% and decreased 25(OH)D3 21% versus placebo (p creatine phosphokinase 24 h post-exercise, 169%, 32%, p athletes following eccentric exercise. PMID:24362707

ACUTE EFFECTS OF MOVEMENT VELOCITY ON BLOOD LACTATE AND GROWTH HORMONE RESPONSES AFTER ECCENTRIC BENCH PRESS EXERCISE IN RESISTANCE-TRAINED MEN

OpenAIRE

Calixto, RD; Verlengia, R; Crisp, AH; Carvalho, TB; Crepaldi, MD; Pereira, AA; Yamada, AK; da Mota, GR; Lopes, CR

2014-01-01

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric...

Eccentric crank variable compression ratio mechanism

Science.gov (United States)

Lawrence, Keith Edward [Kobe, JP; Moser, William Elliott [Peoria, IL; Roozenboom, Stephan Donald [Washington, IL; Knox, Kevin Jay [Peoria, IL

2008-05-13

A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

Reducing orbital eccentricity in binary black hole simulations

International Nuclear Information System (INIS)

Pfeiffer, Harald P; Brown, Duncan A; Kidder, Lawrence E; Lindblom, Lee; Lovelace, Geoffrey; Scheel, Mark A

2007-01-01

Binary black hole simulations starting from quasi-circular (i.e., zero radial velocity) initial data have orbits with small but nonzero orbital eccentricities. In this paper, the quasi-equilibrium initial-data method is extended to allow nonzero radial velocities to be specified in binary black hole initial data. New low-eccentricity initial data are obtained by adjusting the orbital frequency and radial velocities to minimize the orbital eccentricity, and the resulting (∼5 orbit) evolutions are compared with those of quasi-circular initial data. Evolutions of the quasi-circular data clearly show eccentric orbits, with eccentricity that decays over time. The precise decay rate depends on the definition of eccentricity; if defined in terms of variations in the orbital frequency, the decay rate agrees well with the prediction of Peters (1964 Phys. Rev. 136 1224-32). The gravitational waveforms, which contain ∼8 cycles in the dominant l = m = 2 mode, are largely unaffected by the eccentricity of the quasi-circular initial data. The overlap between the dominant mode in the quasi-circular evolution and the same mode in the low-eccentricity evolution is about 0.99

Eccentricity from transit photometry

DEFF Research Database (Denmark)

Van Eylen, Vincent; Albrecht, Simon

2015-01-01

and can be described by a Rayleigh distribution with $\\sigma$ = 0.049 $\\pm$ 0.013. This is in full agreement with solar system eccentricities, but in contrast to the eccentricity distributions previously derived for exoplanets from radial velocity studies. Our findings are helpful in identifying which...... (TTVs), and we present some previously unreported TTVs. Finally transit durations help distinguish between false positives and true planets and we use our measurements to confirm six new exoplanets....

Eccentric Contraction-Induced Muscle Injury: Reproducible, Quantitative, Physiological Models to Impair Skeletal Muscle's Capacity to Generate Force.

Science.gov (United States)

Call, Jarrod A; Lowe, Dawn A

2016-01-01

In order to investigate the molecular and cellular mechanisms of muscle regeneration an experimental injury model is required. Advantages of eccentric contraction-induced injury are that it is a controllable, reproducible, and physiologically relevant model to cause muscle injury, with injury being defined as a loss of force generating capacity. While eccentric contractions can be incorporated into conscious animal study designs such as downhill treadmill running, electrophysiological approaches to elicit eccentric contractions and examine muscle contractility, for example before and after the injurious eccentric contractions, allows researchers to circumvent common issues in determining muscle function in a conscious animal (e.g., unwillingness to participate). Herein, we describe in vitro and in vivo methods that are reliable, repeatable, and truly maximal because the muscle contractions are evoked in a controlled, quantifiable manner independent of subject motivation. Both methods can be used to initiate eccentric contraction-induced injury and are suitable for monitoring functional muscle regeneration hours to days to weeks post-injury.

Shedding light on the eccentricity valley: Gap heating and eccentricity excitation of giant planets in protoplanetary disks

International Nuclear Information System (INIS)

Tsang, David; Cumming, Andrew; Turner, Neal J.

2014-01-01

We show that the first order (non-co-orbital) corotation torques are significantly modified by entropy gradients in a non-barotropic protoplanetary disk. Such non-barotropic torques can dramatically alter the balance that, for barotropic cases, results in the net eccentricity damping for giant gap-clearing planets embedded in the disk. We demonstrate that stellar illumination can heat the gap enough for the planet's orbital eccentricity to instead be excited. We also discuss the 'Eccentricity Valley' noted in the known exoplanet population, where low-metallicity stars have a deficit of eccentric planets between ∼0.1 and ∼1 AU compared to metal-rich systems. We show that this feature in the planet distribution may be due to the self-shadowing of the disk by a rim located at the dust sublimation radius ∼0.1 AU, which is known to exist for several T Tauri systems. In the shadowed region between ∼0.1 and ∼1 AU, lack of gap insolation allows disk interactions to damp eccentricity. Outside such shadowed regions stellar illumination can heat the planetary gaps and drive eccentricity growth for giant planets. We suggest that the self-shadowing does not arise at higher metallicity due to the increased optical depth of the gas interior to the dust sublimation radius.

Shedding light on the eccentricity valley: Gap heating and eccentricity excitation of giant planets in protoplanetary disks

Energy Technology Data Exchange (ETDEWEB)

Tsang, David; Cumming, Andrew [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Turner, Neal J., E-mail: dtsang@physics.mcgill.ca [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2014-02-20

We show that the first order (non-co-orbital) corotation torques are significantly modified by entropy gradients in a non-barotropic protoplanetary disk. Such non-barotropic torques can dramatically alter the balance that, for barotropic cases, results in the net eccentricity damping for giant gap-clearing planets embedded in the disk. We demonstrate that stellar illumination can heat the gap enough for the planet's orbital eccentricity to instead be excited. We also discuss the 'Eccentricity Valley' noted in the known exoplanet population, where low-metallicity stars have a deficit of eccentric planets between ∼0.1 and ∼1 AU compared to metal-rich systems. We show that this feature in the planet distribution may be due to the self-shadowing of the disk by a rim located at the dust sublimation radius ∼0.1 AU, which is known to exist for several T Tauri systems. In the shadowed region between ∼0.1 and ∼1 AU, lack of gap insolation allows disk interactions to damp eccentricity. Outside such shadowed regions stellar illumination can heat the planetary gaps and drive eccentricity growth for giant planets. We suggest that the self-shadowing does not arise at higher metallicity due to the increased optical depth of the gas interior to the dust sublimation radius.

The role of eccentric regime of leg muscle work in alpine skiing

Directory of Open Access Journals (Sweden)

Ropret Robert

2017-01-01

Full Text Available Alpine skiing is characterized by a great number of leg movements with muscle contractions in eccentric regime. The role of these movements is to absorb gravitation and inertial forces, manage skis more precisely and maintain balance. Recent studies have determined the volume, duration and intenisty of eccentric contractions as well as the basic characteristics of movement amplitudes and velocities. Based on the previous findings the experiments involving eccentric training using a bicycle ergometer confirmed a positive impact that this kind of training has on increasing maximum power, strength, endurance, coordination, injury prevention, metabolic work efficiency, more efficient work with longer muscle length and its role in miming skiers' movements. This paper is an review of the studies so far in the field of kinematics, skiing dynamics and the effect of eccentric training on the development of athletes' performances.

Neuromuscular and muscle-tendon system adaptations to isotonic and isokinetic eccentric exercise.

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Guilhem, G; Cornu, C; Guével, A

2010-06-01

To present the properties of an eccentric contraction and compare neuromuscular and muscle-tendon system adaptations induced by isotonic and isokinetic eccentric trainings. An eccentric muscle contraction is characterized by the production of muscle force associated to a lengthening of the muscle-tendon system. This muscle solicitation can cause micro lesions followed by a regeneration process of the muscle-tendon system. Eccentric exercise is commonly used in functional rehabilitation for its positive effect on collagen synthesis but also for resistance training to increase muscle strength and muscle mass in athletes. Indeed, eccentric training stimulates muscle hypertrophy, increases the fascicle pennation angle, fascicles length and neural activation, thus inducing greater strength gains than concentric or isometric training programs. Eccentric exercise is commonly performed either against a constant external load (isotonic) or at constant velocity (isokinetic), inducing different mechanical constraints. These different mechanical constraints could induce structural and neural adaptive strategies specific to each type of exercise. The literature tends to show that isotonic mode leads to a greater strength gain than isokinetic mode. This observation could be explained by a greater neuromuscular activation after IT training. However, the specific muscle adaptations induced by each mode remain difficult to determine due to the lack of standardized, comparative studies. 2010 Elsevier Masson SAS. All rights reserved.

Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy

Science.gov (United States)

Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

1992-01-01

This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

Effects of fast-velocity eccentric resistance training on early and late rate of force development

DEFF Research Database (Denmark)

Oliveira, Anderson S.C.; Corvino, Rogério Bulhões; Caputo, Fabrizio

2016-01-01

This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (phases (>100 ms) of rising torque. Twenty healthy men were......, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL...... assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180°s-1. Maximal isometric knee extensor torque (MVC...

The effect of eccentric and concentric calf muscle training on Achilles tendon stiffness.

Science.gov (United States)

Morrissey, Dylan; Roskilly, Anna; Twycross-Lewis, Richard; Isinkaye, Tomide; Screen, Hazel; Woledge, Roger; Bader, Dan

2011-03-01

To compare in vivo effects of eccentric and concentric calf muscle training on Achilles tendon stiffness, in subjects without tendinopathy. Thirty-eight recreational athletes completed 6 weeks eccentric (6 males, 13 females, 21.6  ±  2.2 years) or concentric training (8 males, 11 females, 21.1  ±  2.0 years). Achilles tendon stiffness, tendon modulus and single-leg jump height were measured before and after intervention. Exercise adherence was recorded using a diary. All data are reported as mean  ±  SD. Groups were matched for height and weight but the eccentric training group were more active at baseline (P Tendon stiffness was higher in the eccentrically trained group at baseline compared to the concentrically trained group (20.9  ±  7.3 N/mm v 13.38  ±  4.66 N/mm; P = 0.001) and decreased significantly after eccentric training (to 17.2 ( ±  5.9) N/mm (P = 0.035)). There was no stiffness change in the concentric group (P = 0.405). Stiffness modulus showed similar changes to stiffness. An inverse correlation was found between initial, and subsequent, reduction in stiffness (r = -0.66). Jump height did not change and no correlation between stiffness change and adherence was observed in either group (r = 0.01). Six weeks of eccentric training can alter Achilles tendon stiffness while a matched concentric programme shows no similar effects. Studies in patients with Achilles tendinopathy are warranted.

Effects of eccentric cycling exercise on IGF-I splice variant expression in the muscles of young and elderly people

DEFF Research Database (Denmark)

Hameed, M.; Toft, A.D.; Harridge, S.D.

2008-01-01

growth factor (MGF) were studied in response to 1 h of eccentric cycling exercise in young and old individuals. Subjects (nine young, aged 20-27 years and eight elderly, aged 67-75 years) completed an eccentric exercise protocol that consisted of 60 min of reverse pedal cycling. Workloads were chosen......Recovery from micro damage resulting from intensive exercise has been shown to take longer in older muscles. To investigate the factors that may contribute to muscle repair, we have studied the expression of two splice variants of the insulin-like growth factor-I (IGF-I) gene. IGF-IEa and mechano....... No difference was observed between the baseline levels of the two splice variants between the two subject groups. Eccentric cycling exercise resulted in a significant increase in the mean MGF mRNA in both young and old subjects but did not alter IGF-IEa mRNA levels in either age group. As reported previously...

Influence of Arm-cranking on Changes in Plasma CK Activity after High Force Eccentric Exercise of the Elbow Flexors

OpenAIRE

Kazunori, NOSAKA; Kei, SAKAMOTO; Mike, NEWTON; Exercise and Sports Science, Graduate School of Integrated Science, Yokohama City University:School of Biomedical and Sports Science, Edith Cowan University; Exercise and Sports Science, Graduate School of Integrated Science, Yokohama City University; School of Biomedical and Sports Science, Edith Cowan University

2002-01-01

It was hypothesized that the time course of changes in plasma creatine kinase (CK) activity following eccentric exercise was influenced by rhythmical muscle contractions performed after eccentric exercise. This study examined whether arm-cranking (AC) alters the time course of changes in plasma creatine kinase (CK) activity after eccentric exercise of the elbow flexors (ECC). Six male students performed two bouts of ECC separated by 3 weeks, and AC (25watts, 2-hours) was performed immediately...

THE ECCENTRIC KOZAI MECHANISM FOR A TEST PARTICLE

International Nuclear Information System (INIS)

Lithwick, Yoram; Naoz, Smadar

2011-01-01

We study the dynamical evolution of a test particle that orbits a star in the presence of an exterior massive planet, considering octupole-order secular interactions. In the standard Kozai mechanism (SKM), the planet's orbit is circular and so the particle conserves vertical angular momentum. As a result, the particle's orbit oscillates periodically, exchanging eccentricity for inclination. However, when the planet's orbit is eccentric, the particle's vertical angular momentum varies and its Kozai oscillations are modulated on longer timescales—we call this the eccentric Kozai mechanism (EKM). The EKM can lead to behavior that is dramatically different from the SKM. In particular, the particle's orbit can flip from prograde to retrograde and back again, and it can reach arbitrarily high eccentricities given enough time. We map out the conditions under which this dramatic behavior (flipping and extreme eccentricities) occurs and show that when the planet's eccentricity is sufficiently high, it occurs quite generically. For example, when the planet's eccentricity exceeds a few percent of the ratio of semimajor axes (outer to inner), around half of randomly oriented test particle orbits will flip and reach extreme eccentricities. The SKM has often been invoked for bringing pairs of astronomical bodies (star-star, planet-star, compact-object pairs) close together. Including the effect of the EKM will enhance the rate at which such matchmaking occurs.

Attenuation of muscle damage by preconditioning with muscle hyperthermia 1-day prior to eccentric exercise.

Science.gov (United States)

Nosaka, K; Muthalib, M; Lavender, A; Laursen, P B

2007-01-01

This study investigated the hypothesis that muscle damage would be attenuated in muscles subjected to passive hyperthermia 1 day prior to exercise. Fifteen male students performed 24 maximal eccentric actions of the elbow flexors with one arm; the opposite arm performed the same exercise 2-4 weeks later. The elbow flexors of one arm received a microwave diathermy treatment that increased muscle temperature to over 40 degrees C, 16-20 h prior to the exercise. The contralateral arm acted as an untreated control. Maximal voluntary isometric contraction strength (MVC), range of motion (ROM), upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration were measured 1 day prior to exercise, immediately before and after exercise, and daily for 4 days following exercise. Changes in the criterion measures were compared between conditions (treatment vs. control) using a two-way repeated measures ANOVA with a significance level of P < 0.05. All measures changed significantly following exercise, but the treatment arm showed a significantly faster recovery of MVC, a smaller change in ROM, and less muscle soreness compared with the control arm. However, the protective effect conferred by the diathermy treatment was significantly less effective compared with that seen in the second bout performed 4-6 weeks after the initial bout by a subgroup of the subjects (n = 11) using the control arm. These results suggest that passive hyperthermia treatment 1 day prior to eccentric exercise-induced muscle damage has a prophylactic effect, but the effect is not as strong as the repeated bout effect.

Acute effects of movement velocity on blood lactate and growth hormone responses after eccentric bench press exercise in resistance-trained men.

Science.gov (United States)

Calixto, Rd; Verlengia, R; Crisp, Ah; Carvalho, Tb; Crepaldi, Md; Pereira, Aa; Yamada, Ak; da Mota, Gr; Lopes, Cr

2014-12-01

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P bench press exercise in the SEV group (1.7 ± 0.6 ng · mL(-1)) relative to the FEV group (0.1 ± 0.0 ng · mL(-1)). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response.

Biomechanical characteristics of the eccentric Achilles tendon exercise

DEFF Research Database (Denmark)

Henriksen, Marius; Aaboe, Jens; Bliddal, Henning

2009-01-01

that although the tendon loads are similar, the tendon is vibrated at higher frequencies during the eccentric phase than during the concentric phases. This study provides data that may explain the mechanisms behind the effectiveness of eccentric exercises used in the treatment of Achilles tendinopathies........ No differences in Achilles tendon loads were found. INTERPRETATION: This descriptive study demonstrates differences in the movement biomechanics between the eccentric and concentric phases of one-legged full weight bearing ankle dorsal and plantar flexion exercises. In particular, the findings imply......BACKGROUND: Eccentric exercise has been shown to provide good short-term clinical results in the treatment of painful mid-portion chronic Achilles tendinopathies. However, the mechanisms behind the positive effects of eccentric rehabilitation regimes are not known, and research...

Eccentric training for shoulder abductors improves pain, function and isokinetic performance in subjects with shoulder impingement syndrome: a case series Treino excêntrico para abdutores do ombro melhora dor, função e desempenho isocinético em sujeitos com síndrome do impacto: série de casos

Directory of Open Access Journals (Sweden)

Paula R. Camargo

2012-02-01

Full Text Available BACKGROUND: Conservative treatments have been proposed for people with shoulder impingement syndrome (SIS, such as strengthening of the rotator cuff and scapular muscles and stretching of the soft tissues of the shoulder. However, there is a lack of studies analyzing the effectiveness of eccentric training in the treatment of SIS. OBJECTIVES: To evaluate the effects of eccentric training for shoulder abductors on pain, function, and isokinetic performance during concentric and eccentric abduction of the shoulder in subjects with SIS. METHODS: Twenty subjects (7 females, 34.2 SD 10.2 years, 1.7 SD 0.1 m, 78.0 SD 16.3 kg with unilateral SIS completed the study protocol. Bilateral isokinetic eccentric training at 60º/s for shoulder abductors was performed for six consecutive weeks, twice a week, on alternate days. For each training day, three sets of 10 repetitions were performed with a 3-minute rest period between the sets for each side. The range of motion trained was 60° (ranging from 80° to 20°. The Disabilities of the Arm, Shoulder and Hand (DASH questionnaire was used to evaluate functional status and symptoms of the upper limbs. Peak torque, total work and acceleration time were measured during concentric and eccentric abduction of the arm at 60º/s and 180º/s using an isokinetic dynamometer. RESULTS: DASH scores, peak torque, total work and acceleration time improved (pCONTEXTUALIZAÇÃO: Tratamentos conservadores têm sido propostos para pessoas com síndrome do impacto (SI do ombro, como fortalecimento do manguito rotador e dos músculos escapulares e alongamento dos tecidos moles do ombro. No entanto, são escassos os estudos que analisaram a eficácia do treinamento excêntrico no tratamento da SI. OBJETIVOS: Avaliar os efeitos do treinamento excêntrico para abdutores do ombro na dor, função e desempenho isocinético durante a abdução concêntrica e excêntrica do ombro em indivíduos com SI. MÉTODOS: Vinte indivíduos (sete

Eccentric exercises for the management of tendinopathy of the main body of the Achilles tendon with or without the AirHeel Brace. A randomized controlled trial. A: effects on pain and microcirculation.

Science.gov (United States)

Knobloch, Karsten; Schreibmueller, Louisa; Longo, Umile Giuseppe; Vogt, Peter M

2008-01-01

To compare eccentric training and the combination of eccentric training with the AirHeel Brace for the management of tendinopathy of the main body of the Achilles tendon. We recruited 116 subjects with unilateral tendinopathy of the main body of the Achilles tendon, who were randomized in two groups. Group A performed a regimen of daily eccentric training associated with the AirHeel Brace (Donjoy Orthopedics, Vista, CA, USA). Group B performed the same eccentric training without the AirHeel Brace. Tendon microcirculatory mapping was performed using combined Laser-Doppler and spectrophotometry. Pre- and post-operative FAOS score and VAS score were used to evaluate the patients. The FAOS score and the VAS score showed significant improvements from pre-operative to post-operative values in both groups (A 5.1 +/- 2 vs. 2.9 +/- 2.4, 43% reduction and B: 5.4 +/- 2.1 vs. 3.6 +/- 2.4, 33% reduction, both p = 0.0001). There were no statistically significant differences in FAOS score and VAS score when comparing the two groups after the end of the intervention. In Group A, tendon oxygen saturation in the main body of the Achilles tendon showed significant increase from pre- to post-management values (68 +/- 12 vs.74 +/- 8%, p = 0.003). Post-capillary venous filling pressures showed significant reduction from pre- to post-intervention values. Eccentric training, associated or not with the AirHeel Brace, produces the same effect in patients with tendinopathy of the main body of the Achilles tendon. The combination of eccentric training with the AirHeel Brace can optimize tendon microcirculation, but these micro-circulator advantages do not translate into superior clinical performance when compared with eccentric training alone.

EXTRACTING PLANET MASS AND ECCENTRICITY FROM TTV DATA

International Nuclear Information System (INIS)

Lithwick, Yoram; Xie Jiwei; Wu Yanqin

2012-01-01

Most planet pairs in the Kepler data that have measured transit time variations (TTVs) are near first-order mean-motion resonances. We derive analytical formulae for their TTV signals. We separate planet eccentricity into free and forced parts, where the forced part is purely due to the planets' proximity to resonance. This separation yields simple analytical formulae. The phase of the TTV depends sensitively on the presence of free eccentricity: if the free eccentricity vanishes, the TTV will be in phase with the longitude of conjunctions. This effect is easily detectable in current TTV data. The amplitude of the TTV depends on planet mass and free eccentricity, and it determines planet mass uniquely only when the free eccentricity is sufficiently small. We analyze the TTV signals of six short-period Kepler pairs. We find that three of these pairs (Kepler 18, 24, 25) have a TTV phase consistent with zero. The other three (Kepler 23, 28, 32) have small TTV phases, but ones that are distinctly non-zero. We deduce that the free eccentricities of the planets are small, ∼< 0.01, but not always vanishing. Furthermore, as a consequence of this, we deduce that the true masses of the planets are fairly accurately determined by the TTV amplitudes, within a factor of ∼< 2. The smallness of the free eccentricities suggests that the planets have experienced substantial dissipation. This is consistent with the hypothesis that the observed pile-up of Kepler pairs near mean-motion resonances is caused by resonant repulsion. But the fact that some of the planets have non-vanishing free eccentricity suggests that after resonant repulsion occurred there was a subsequent phase in the planets' evolution when their eccentricities were modestly excited, perhaps by interplanetary interactions.

The development of a repetition-load scheme for the eccentric-only bench press exercise.

Science.gov (United States)

Moir, Gavin L; Erny, Kyle F; Davis, Shala E; Guers, John J; Witmer, Chad A

2013-01-01

The purpose of the present study was to develop a repetition-load scheme for the eccentric-only bench press exercise. Nine resistance trained men (age: 21.6 ± 1.0 years; 1-repetition maximum [RM] bench press: 137.7 ± 30.4 kg) attended four testing sessions during a four week period. During the first session each subject's 1-RM bench press load utilizing the stretch-shortening cycle was determined. During the remaining sessions they performed eccentric-only repetitions to failure using supra-maximal loads equivalent to 110%, 120% and 130% of their 1-RM value with a constant cadence (30 reps·min(-1)). Force plates and a three dimensional motion analysis system were used during these final three sessions in order to evaluate kinematic and kinetic variables. More repetitions were completed during the 110% 1-RM condition compared to the 130% 1-RM condition (p=0.01). Mean total work (p=0.046) as well as vertical force (p=0.049), vertical work (p=0.017), and vertical power output (p=0.05) were significantly greater during the 130% 1-RM condition compared to the 110% 1-RM condition. A linear function was fitted to the number of repetitions completed under each load condition that allowed the determination of the maximum number of repetitions that could be completed under other supra-maximal loads. This linear function predicted an eccentric-only 1-RM in the bench press with a load equivalent to 164.8% 1-RM, producing a load of 227.0 ± 50.0 kg. The repetition-load scheme presented here should provide a starting point for researchers to investigate the kinematic, kinetic and metabolic responses to eccentric-only bench press workouts.

A comprehensive study on the influence of strength and stiffness eccentricities to the on-plan rotation of asymmetric structure

Science.gov (United States)

Rashidi, Azida; Majid, Taksiah A.; Fadzli, M. N.; Faisal, Ade; Noor, Suhaila M.

2017-10-01

All buildings are subjected to some degree of torsion which in turn changes the member torsional demands from that of translation only. Torsional effects on buildings subjected to earthquakes are not found directly in structural analysis unless full three-dimensional inelastic dynamic time history analysis is conducted. Since design is often conducted using two-dimensional analysis, these effects are not directly considered. There is currently an understanding on how different factors may influence torsion, however, the degree to which these factors influence torsion is relatively unknown. Slab rotation effect is considered a major response parameter to represent the severity of the torsional response of eccentric systems; hence, it is considered in this study. The centre of strength (CR) and centre of stiffness (CS) are the two main factors under considerations. A comprehensive analysis on eighty different CR and CS conditions are applied to a three-dimensional, asymmetric building and their influences to slab rotation are observed. The CR/CS conditions are applied by varying strength eccentricities (er) and stiffness eccentricities (es) using two condition models. Then, earthquake ground motions are applied in z-direction under elastic and inelastic conditions. The results interpreted using a simple approach shows important slab rotation behaviour that forms interesting findings from this study. The slab rotation demand is found to reduce as strength eccentricity moves away from the Centre of Mass (CoM) but is independent of the stiffness eccentricity. The study also confirms finding of previous works which states that stiffness eccentricity plays a minor role when assessing the torsional behaviour of a ductile systems. Results from inelastic analysis shows slab rotation demand increases as strength eccentricity is closer to the CoM but it remains constant for elastic analysis.

COMPARISON OF PATHWAY AND CENTER OF GRAVITY OF THE CALCANEUS ON NON-INVOLVED AND INVOLVED SIDES ACCORDING TO ECCENTRIC AND CONCENTRIC STRENGTHENING IN PATIENTS WITH ACHILLES TENDINOPATHY

Directory of Open Access Journals (Sweden)

JaeHo Yu

2012-03-01

Full Text Available This study compares the changes in pathway and center of gravity (COG on the calcaneus of non-involved and involved sides according to eccentric and concentric strengthening in patients with unilateral Achilles tendinopathy. The goal was to define the biomechanical changes according to eccentric strengthening for the development of clinical guidelines. Eighteen patients with Achilles tendinopathy were recruited at the K Rehabilitation Hospital in Seoul. The subjects were instructed to perform 5 sessions of concentric strengthening. The calcaneal pathway was measured using a three-dimensional (3D motion analyzer, and COG was measured by a force plate. Subsequently, eccentric strengthening was implemented, and identical variables were measured. Concentric and eccentric strengthening was carried out on both the involved and non-involved sides. There was no significant difference in the calcaneal pathway in patients with Achilles tendinopathy during concentric and eccentric strengthening. However, during eccentric strengthening, the calcaneal pathway significantly increased on the involved side compared to the non-involved side for all variables excluding the z-axis. COG significantly decreased on the involved side when compared to the non-involved side in patients with Achilles tendinopathy during eccentric and concentric strengthening. During concentric strengthening, all variables of the COG significantly increased on the involved side compared to the non-involved side. Compared with eccentric strengthening, concentric strengthening decreased the stability of ankle joints and increased the movement distance of the calcaneus in patients with Achilles tendinopathy. Furthermore, eccentric strengthening was verified to be an effective exercise method for prevention of Achilles tendinopathy through the reduction of forward and backward path length of foot pressure. The regular application of eccentric strengthening was found to be effective in the

Quasi-eccentricity error modeling and compensation in vision metrology

Science.gov (United States)

Shen, Yijun; Zhang, Xu; Cheng, Wei; Zhu, Limin

2018-04-01

Circular targets are commonly used in vision applications for its detection accuracy and robustness. The eccentricity error of the circular target caused by perspective projection is one of the main factors of measurement error which needs to be compensated in high-accuracy measurement. In this study, the impact of the lens distortion on the eccentricity error is comprehensively investigated. The traditional eccentricity error turns to a quasi-eccentricity error in the non-linear camera model. The quasi-eccentricity error model is established by comparing the quasi-center of the distorted ellipse with the true projection of the object circle center. Then, an eccentricity error compensation framework is proposed which compensates the error by iteratively refining the image point to the true projection of the circle center. Both simulation and real experiment confirm the effectiveness of the proposed method in several vision applications.

Moderate Load Eccentric Exercise; A Distinct Novel Training Modality

Science.gov (United States)

Hoppeler, Hans

2016-01-01

Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial 3 weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400–500 W in rehabilitative settings and over 1200 W in elite athletes. Training is typically carried out three times per week for durations of 20–30 min. This type of training has been characterizes as moderate load eccentric exercise. It has also been denoted RENEW (Resistance Exercise via Negative Eccentric Work by LaStayo et al., 2014). It is distinct from plyometric exercises (i.e., drop jumps) that impose muscle loads of several thousand Watts on muscles and tendons. It is also distinct from eccentric overload training whereby loads in a conventional strength training setting are increased in the eccentric phase of the movement to match concentric loads. Moderate load eccentric exercise (or RENEW) has been shown to be similarly effective as conventional strength training in increasing muscle strength and muscle volume. However, as carried out at higher angular velocities of joint movement, it reduces joint loads. A hallmark of moderate load eccentric exercise is the fact that the energy requirements are typically 4-fold smaller than in concentric exercise of the same load. This makes moderate load eccentric exercise training the tool of choice in medical conditions with limitations in muscle energy supply. The use and effectiveness of moderate load eccentric exercise has been demonstrated mostly in small scale studies for cardiorespiratory conditions, sarcopenia of old age, cancer, diabetes type 2, and neurological conditions. It has also been used effectively in the prevention and rehabilitation of injuries of the locomotor system in particular the rehabilitation after anterior

Sex differences in neuromuscular function after repeated eccentric contractions of the knee extensor muscles.

Science.gov (United States)

Lee, Andrea; Baxter, Jake; Eischer, Claire; Gage, Matt; Hunter, Sandra; Yoon, Tejin

2017-06-01

This study examined the mechanisms for force and power reduction during and up to 48 h after maximal eccentric contractions of the knee extensor muscles in young men and women. 13 men (22.8 ± 2.6 years) and 13 women (21.6 ± 2.2 years) performed 150 maximal effort eccentric contractions (5 sets of 30) with the knee extensor muscles at 60° s -1 . Maximal voluntary isometric contractions (MVIC) and maximal voluntary concentric contractions (MVCC) were performed before and after the 150 eccentric contractions. The MVCCs involved a set of two isokinetic contractions at 60° s -1 and sets of isotonic contractions performed at seven different resistance loads (1 N m, 10, 20, 30, 40, 50, and 60% MVIC). Electrical stimulation was used during the MVICs and at rest to determine changes in voluntary activation and contractile properties. At baseline, men were stronger than women (MVIC: 276 ± 48 vs. 133 ± 37 N m) and more powerful (MVCC: 649 ± 77 vs. 346 ± 78 W). At termination of the eccentric contractions, voluntary activation, resting twitch amplitude, and peak power during concentric contractions at the seven loads and at 60° s -1 decreased (P  0.05) with no sex differences. Central mechanisms were primarily responsible for the depressed maximal force production up to 48 h after repeated eccentric contractions of the knee extensors and these mechanisms were similar in men and women.

Heat transfer in CO{sub 2} at supercritical pressures in an eccentric annular channel

Energy Technology Data Exchange (ETDEWEB)

Bae, Yoon-Yeong, E-mail: yybae@kaeri.re.kr

2013-12-15

Highlights: • Heat transfer under supercritical pressure in an eccentric annular channel pressure was studied. • The studied geometry was an eccentric annular channel with an eccentricity of 0.33. • The effect of spacer as a turbulence generator was investigated. • The effects of the mass flux, heat flux, and pressure were investigated. • The obtained data were evaluated against the correlation. - Abstract: An experimental investigation of a supercritical heat transfer in an eccentric annular channel was performed using a supercritical heat transfer test facility, SPHINX, at the Korea Atomic Energy Research Institute (KAERI). The eccentric channel was built by placing a 9.5 mm outer diameter heater rod in a 12.5 mm inner diameter tube with an eccentricity of 0.33. The narrowest gap was 1 mm, and the widest gap was 2 mm. The rod was heated indirectly by an imbedded Nickel Chrome heating wire made of NCHW1. Three simple spacers were installed to see their effect, if any, on the heat transfer. The mass fluxes were 400 and 1200 kg/m{sup 2} s, and the heat flux was varied between 30 and 150 kW/m{sup 2} such that the pseudo-critical point was located within the test section as long as possible. When this was not the case, several tests with stepwise increased inlet temperatures were performed so that at least one of them included the pseudo-critical point. The tests were performed at two different pressures of 7.75 and 8.12 MPa to check the pressure effect. The influence of the gap size was clearly seen with the eccentric channel, if not significant. The wall temperatures along the narrowest gap were higher than those along the widest gap as expected, while it was reversed at the end part of the test section. The test results for the eccentric channel were not much different from those for the concentric channel of a similar gap size. As we have seen from the plain tube test, the diameter effect on the heat transfer was also not significant in this test. On the

Eccentric muscle damage has variable effects on motor unit recruitment thresholds and discharge patterns in elbow flexor muscles.

Science.gov (United States)

Dartnall, Tamara J; Rogasch, Nigel C; Nordstrom, Michael A; Semmler, John G

2009-07-01

The purpose of this study was to determine the effect of eccentric muscle damage on recruitment threshold force and repetitive discharge properties of low-threshold motor units. Ten subjects performed four tasks involving isometric contraction of elbow flexors while electromyographic (EMG) data were recorded from human biceps brachii and brachialis muscles. Tasks were 1) maximum voluntary contraction (MVC); 2) constant-force contraction at various submaximal targets; 3) motor unit recruitment threshold task; and 4) minimum motor unit discharge rate task. These tasks were performed on three separate days before, immediately after, and 24 h after eccentric exercise of elbow flexor muscles. MVC force declined (42%) immediately after exercise and remained depressed (29%) 24 h later, indicative of muscle damage. Mean motor unit recruitment threshold for biceps brachii was 8.4+/-4.2% MVC, (n=34) before eccentric exercise, and was reduced by 41% (5.0+/-3.0% MVC, n=34) immediately after and by 39% (5.2+/-2.5% MVC, n=34) 24 h after exercise. No significant changes in motor unit recruitment threshold were observed in the brachialis muscle. However, for the minimum tonic discharge rate task, motor units in both muscles discharged 11% faster (10.8+/-2.0 vs. 9.7+/-1.7 Hz) immediately after (n=29) exercise compared with that before (n=32). The minimum discharge rate variability was greater in brachialis muscle immediately after exercise (13.8+/-3.1%) compared with that before (11.9+/-3.1%) and 24 h after exercise (11.7+/-2.4%). No significant changes in minimum discharge rate variability were observed in the biceps brachii motor units after exercise. These results indicate that muscle damage from eccentric exercise alters motor unit recruitment thresholds for >or=24 h, but the effect is not the same in the different elbow flexor muscles.

Effect of eccentricity on searches for gravitational waves from coalescing compact binaries in ground-based detectors

International Nuclear Information System (INIS)

Brown, Duncan A.; Zimmerman, Peter J.

2010-01-01

Inspiralling compact binaries are expected to circularize before their gravitational-wave signals reach the sensitive frequency band of ground-based detectors. Current searches for gravitational waves from compact binaries using the LIGO and Virgo detectors therefore use circular templates to construct matched filters. Binary formation models have been proposed which suggest that some systems detectable by the LIGO-Virgo network may have non-negligible eccentricity. We investigate the ability of the restricted 3.5 post-Newtonian order TaylorF2 template bank, used by LIGO and Virgo to search for gravitational waves from compact binaries with masses M≤35M · , to detect binaries with nonzero eccentricity. We model the gravitational waves from eccentric binaries using the x-model post-Newtonian formalism proposed by Hinder et al.[I. Hinder, F. Hermann, P. Laguna, and D. Shoemaker, arXiv:0806.1037v1]. We find that small residual eccentricities (e 0 · · . For eccentricities e 0 > or approx. 0.1, the loss in matched filter signal-to-noise ratio due to eccentricity can be significant and so templates which include eccentric effects will be required to perform optimal searches for such systems.

Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy

DEFF Research Database (Denmark)

Beyer, Rikke; Kongsgaard, Mads; Hougs Kjær, Birgitte

2015-01-01

BACKGROUND: Previous studies have shown that eccentric training has a positive effect on Achilles tendinopathy, but few randomized controlled trials have compared it with other loading-based treatment regimens. PURPOSE: To evaluate the effectiveness of eccentric training (ECC) and heavy slow...... (Victorian Institute of Sports Assessment-Achilles), tendon pain during activity (visual analog scale), tendon swelling, tendon neovascularization, and treatment satisfaction were assessed at 0 and 12 weeks and at the 52-week follow-up. Analyses were performed on an intention-to-treat basis. RESULTS: Both...... groups showed significant (P tendon...

Enhanced Glycogen Storage of a Subcellular Hot Spot in Human Skeletal Muscle during Early Recovery from Eccentric Contractions

Science.gov (United States)

Nielsen, Joachim; Farup, Jean; Rahbek, Stine Klejs; de Paoli, Frank Vincenzo; Vissing, Kristian

2015-01-01

Unaccustomed eccentric exercise is accompanied by muscle damage and impaired glucose uptake and glycogen synthesis during subsequent recovery. Recently, it was shown that the role and regulation of glycogen in skeletal muscle are dependent on its subcellular localization, and that glycogen synthesis, as described by the product of glycogen particle size and number, is dependent on the time course of recovery after exercise and carbohydrate availability. In the present study, we investigated the subcellular distribution of glycogen in fibers with high (type I) and low (type II) mitochondrial content during post-exercise recovery from eccentric contractions. Analysis was completed on five male subjects performing an exercise bout consisting of 15 x 10 maximal eccentric contractions. Carbohydrate-rich drinks were subsequently ingested throughout a 48 h recovery period and muscle biopsies for analysis included time points 3, 24 and 48 h post exercise from the exercising leg, whereas biopsies corresponding to prior to and at 48 h after the exercise bout were collected from the non-exercising, control leg. Quantitative imaging by transmission electron microscopy revealed an early (post 3 and 24 h) enhanced storage of intramyofibrillar glycogen (defined as glycogen particles located within the myofibrils) of type I fibers, which was associated with an increase in the number of particles. In contrast, late in recovery (post 48 h), intermyofibrillar, intramyofibrillar and subsarcolemmal glycogen in both type I and II fibers were lower in the exercise leg compared with the control leg, and this was associated with a smaller size of the glycogen particles. We conclude that in the carbohydrate-supplemented state, the effect of eccentric contractions on glycogen metabolism depends on the subcellular localization, muscle fiber’s oxidative capacity, and the time course of recovery. The early enhanced storage of intramyofibrillar glycogen after the eccentric contractions may

Muscle fascicle behavior during eccentric cycling and its relation to muscle soreness.

Science.gov (United States)

Peñailillo, Luis; Blazevich, Anthony J; Nosaka, Kazunori

2015-04-01

A single bout of eccentric exercise confers a protective effect against muscle damage and soreness in subsequent eccentric exercise bouts, but the mechanisms underpinning this effect are unclear. This study compared vastus lateralis (VL) muscle-tendon behavior between two eccentric cycling bouts to test the hypothesis that muscle-tendon behavior would be different between bouts and would be associated with the protective effect. Eleven untrained men (27.1 ± 7.0 yr) performed two bouts of eccentric cycling (ECC1 and ECC2) separated by 2 wk for 10 min at 65% of maximal concentric workload (191.9 ± 44.2 W) each. Muscle soreness (by visual analog scale) and maximal voluntary isometric contraction (MVC) torque of the knee extensors were assessed before and 1-2 d after exercise. Using ultrasonography, VL fascicle length and angle changes during cycling were assessed, and tendinous tissue (TT) length changes were estimated. VL EMG amplitude, crank torque, and knee joint angles were measured during cycling. Soreness was greater (P tendon behavior may be an important mechanism underpinning the protective effect.

Grinding Method and Error Analysis of Eccentric Shaft Parts

Science.gov (United States)

Wang, Zhiming; Han, Qiushi; Li, Qiguang; Peng, Baoying; Li, Weihua

2017-12-01

RV reducer and various mechanical transmission parts are widely used in eccentric shaft parts, The demand of precision grinding technology for eccentric shaft parts now, In this paper, the model of X-C linkage relation of eccentric shaft grinding is studied; By inversion method, the contour curve of the wheel envelope is deduced, and the distance from the center of eccentric circle is constant. The simulation software of eccentric shaft grinding is developed, the correctness of the model is proved, the influence of the X-axis feed error, the C-axis feed error and the wheel radius error on the grinding process is analyzed, and the corresponding error calculation model is proposed. The simulation analysis is carried out to provide the basis for the contour error compensation.

Ultrasonic guided waves in eccentric annular pipes

International Nuclear Information System (INIS)

Pattanayak, Roson Kumar; Balasubramaniam, Krishnan; Rajagopal, Prabhu

2014-01-01

This paper studies the feasibility of using ultrasonic guided waves to rapidly inspect tubes and pipes for possible eccentricity. While guided waves are well established in the long range inspection of structures such as pipes and plates, studies for more complex cross sections are limited and analytical solutions are often difficult to obtain. Recent developments have made the Semi Analytical Finite Element (SAFE) method widely accessible for researchers to study guided wave properties in complex structures. Here the SAFE method is used to study the effect of eccentricity on the modal structures and velocities of lower order guided wave modes in thin pipes of diameters typically of interest to the industry. Results are validated using experiments. The paper demonstrates that even a small eccentricity in the pipe can strongly affect guided wave mode structures and velocities and hence shows potential for pipe eccentricity inspection

Electromyographic analysis of repeated bouts of eccentric exercise.

Science.gov (United States)

McHugh, M P; Connolly, D A; Eston, R G; Gartman, E J; Gleim, G W

2001-03-01

The repeated bout effect refers to the protective effect provided by a single bout of eccentric exercise against muscle damage from a similar subsequent bout. The aim of this study was to determine if the repeated bout was associated with an increase in motor unit activation relative to force production, an increased recruitment of slow-twitch motor units or increased motor unit synchronization. Surface electromyographic (EMG) signals were recorded from the hamstring muscles during two bouts of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions separated by 2 weeks. The EMG per unit torque and median frequency were analysed. The initial bout of eccentric exercise resulted in strength loss, pain and muscle tenderness, while the repeated eccentric bout resulted in a slight increase in strength, no pain and no muscle tenderness (bout x time effects, P exercise. The EMG per unit torque and median frequency were not different between the initial and repeated bouts of eccentric exercise. The EMG per unit torque and median frequency increased during both bouts of eccentric exercise (P < 0.01) but did not change during either concentric bout. In conclusion, there was no evidence that the repeated bout effect was due to a neural adaptation.

Changes in power and force generation during coupled eccentric-concentric versus concentric muscle contraction with training and aging

DEFF Research Database (Denmark)

Caserotti, Paolo; Aagaard, Per; Puggaard, Lis

2008-01-01

Age-related decline in maximal concentric muscle power is associated with frailty and functional impairments in the elderly. Compared to concentric contraction, mechanical muscle output is generally enhanced when muscles are rapidly pre-stretched (eccentric contraction), albeit less pronounced...... with increasing age. Exercise has been recommended to prevent loss of muscle power and function and recent guidelines indicate training program for increasing muscle power highly relevant for elderly subjects. This study examined the differences in muscle power, force and movement pattern during concentric......) and JH increased in training group (P age-related decline in muscle power and functional performance observed in the control subjects, while substantial gains...

Physiological comparison of concentric and eccentric arm cycling in males and females.

Directory of Open Access Journals (Sweden)

C Martyn Beaven

Full Text Available Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC or concentric (CON arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial. The heart rate, ventilation, cardiac output, respiratory exchange ratio, and blood lactate concentrations were all clearly greater in CON condition at all of the relative workloads (all p0.05. In contrast, delta efficiency (ηΔ, as previously defined by Coyle and colleagues in 1992, demonstrated a sex difference (men>women; p<0.05. Sex differences were also apparent in arteriovenous oxygen difference and heart rate during CON. Here, we reinforce the high-force, low cost attributes of eccentric exercise which can be generalised to the muscles of the upper body. Upper body eccentric exercise is likely to form a useful adjunct in debilitative, rehabilitative, and adaptive clinical exercise programs; however, reports of a shift towards an oxidative phenotype should be taken into consideration by power athletes. We suggest delta efficiency as a sensitive measure of efficiency that allowed the identification of sex differences.

Vitamin D2 Supplementation Amplifies Eccentric Exercise-Induced Muscle Damage in NASCAR Pit Crew Athletes

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David C. Nieman

2013-12-01

Full Text Available This study determined if 6-weeks vitamin D2 supplementation (vitD2, 3800 IU/day had an influence on muscle function, eccentric exercise-induced muscle damage (EIMD, and delayed onset of muscle soreness (DOMS in National Association for Stock Car Auto Racing (NASCAR NASCAR pit crew athletes. Subjects were randomized to vitD2 (n = 13 and placebo (n = 15, and ingested supplements (double-blind for six weeks. Blood samples were collected and muscle function tests conducted pre- and post-study (leg-back and hand grip dynamometer strength tests, body weight bench press to exhaustion, vertical jump, 30-s Wingate test. Post-study, subjects engaged in 90 min eccentric-based exercise, with blood samples and DOMS ratings obtained immediately after and 1- and 2-days post-exercise. Six weeks vitD2 increased serum 25(OHD2 456% and decreased 25(OHD3 21% versus placebo (p < 0.001, p = 0.036, respectively, with no influence on muscle function test scores. The post-study eccentric exercise bout induced EIMD and DOMS, with higher muscle damage biomarkers measured in vitD2 compared to placebo (myoglobin 252%, 122% increase, respectively, p = 0.001; creatine phosphokinase 24 h post-exercise, 169%, 32%, p < 0.001, with no differences for DOMS. In summary, 6-weeks vitD2 (3800 IU/day significantly increased 25(OHD2 and decreased 25(OHD3, had no effect on muscle function tests, and amplified muscle damage markers in NASCAR pit crew athletes following eccentric exercise.

OPEX: Optimized Eccentricity Computation in Graphs

Energy Technology Data Exchange (ETDEWEB)

Henderson, Keith [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2011-11-14

Real-world graphs have many properties of interest, but often these properties are expensive to compute. We focus on eccentricity, radius and diameter in this work. These properties are useful measures of the global connectivity patterns in a graph. Unfortunately, computing eccentricity for all nodes is O(n2) for a graph with n nodes. We present OPEX, a novel combination of optimizations which improves computation time of these properties by orders of magnitude in real-world experiments on graphs of many different sizes. We run OPEX on graphs with up to millions of links. OPEX gives either exact results or bounded approximations, unlike its competitors which give probabilistic approximations or sacrifice node-level information (eccentricity) to compute graphlevel information (diameter).

Dynamic eccentricity fault diagnosis in round rotor synchronous motors

International Nuclear Information System (INIS)

Ebrahimi, Bashir Mahdi; Etemadrezaei, Mohammad; Faiz, Jawad

2011-01-01

Research highlights: → We have presented a novel approach to detect dynamic eccentricity in round rotor synchronous motors. → We have introduced an efficient index based on processing torque using time series data mining method. → The stator current spectrum of the motor under different levels of fault and load are computed. → Winding function method has been employed to model healthy and faulty synchronous motors. -- Abstract: In this paper, a novel approach is presented to detect dynamic eccentricity in round rotor synchronous motors. For this, an efficient index is introduced based on processing developed torque using time series data mining (TSDM) method. This index can be utilized to diagnose eccentricity fault and its degree. The capability of this index to predict dynamic eccentricity is illustrated by investigation of load variation impacts on the nominated index. Stator current spectrum of the faulty synchronous motor under different loads and dynamic eccentricity degrees are computed. Effects of the dynamic eccentricity and load variation simultaneously are scrutinized on the magnitude of 17th and 19th harmonic components as traditional indices for eccentricity fault diagnosis in synchronous motors. Necessity signals and parameters for processing and feature extraction are evaluated by winding function method which is employed to model healthy and faulty synchronous motors.

Response of Coagulation Indices to Two Types of Exercise of Eccentric and Isometric in Male Bodybuilding Athletes

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Maryam Azimpour

2016-05-01

Full Text Available Abstract Background and Objectives: Although activation of blood coagulation system in response to physical activity has been identified to some extent, but the contribution of eccentric activity in comparison with isometric activity as resistance exercise, is not clear yet. Therefore, this research was carried out with the purpose of investigating the effect of one session of eccentric and isometric resistance exercise on some coagulation factors in male bodybuilders. Methods: In this semi-experimental study, 28 volunteers were randomly selected from male bodybuilders and divided into two experimental groups and one control group. One of the experimental groups performed eccentric exercise [controlled return (extension of the elbow flexion movement involving an eccentric contraction] and another group performed isometric exercises (holding barbell while flexing elbows at 45 degrees. In order to assess coagulation indices, blood sampling was performed 15 minutes before and immediately after the exercise. Results: Thromboplastin and prothrombin times did not significantly change immediately after the exercise, but the number of platelets significantly increased in both isometric and eccentric types of exercise immediately after the exercise. Conclusion: The results of isometric and eccentric acute resistance exercise showed that the exercise had no negative impact on blood coagulation factors, and increased coagulation system activity reflects the increased number of platelets. The difference between the results of researches carried out in this direction can be resulted from the difference between the exercise protocols, methods and measurement time, and level of preparedness of the participants in the research.

The relationships of eccentric strength and power with dynamic balance in male footballers.

Science.gov (United States)

Booysen, Marc Jon; Gradidge, Philippe Jean-Luc; Watson, Estelle

2015-01-01

Unilateral balance is critical to kicking accuracy in football. In order to design interventions to improve dynamic balance, knowledge of the relationships between dynamic balance and specific neuromuscular factors such as eccentric strength and power is essential. Therefore, the aim was to determine the relationships of eccentric strength and power with dynamic balance in male footballers. The Y-balance test, eccentric isokinetic strength testing (knee extensors and flexors) and the countermovement jump were assessed in fifty male footballers (university (n = 27, mean age = 20.7 ± 1.84 years) and professional (n = 23, mean age = 23.0 ± 3.08 years). Spearman Rank Order correlations were used to determine the relationships of eccentric strength and power with dynamic balance. Multiple linear regression, adjusting for age, mass, stature, playing experience and competitive level was performed on significant relationships. Normalised reach score in the Y-balance test using the non-dominant leg for stance correlated with (1) eccentric strength of the non-dominant leg knee extensors in the university group (r = 0.50, P = 0.008) and (2) countermovement jump height in the university (r = 0.40, P = 0.04) and professional (r = 0.56, P = 0.006) football groups, respectively. No relationships were observed between eccentric strength (knee flexors) and normalised reach scores. Despite the addition of potential confounders, the relationship of power and dynamic balance was significant (r = 0.52, P power correlates moderately with dynamic balance on the non-dominant leg in male footballers.

Exoplanet orbital eccentricity: multiplicity relation and the Solar System.

Science.gov (United States)

Limbach, Mary Anne; Turner, Edwin L

2015-01-06

The known population of exoplanets exhibits a much wider range of orbital eccentricities than Solar System planets and has a much higher average eccentricity. These facts have been widely interpreted to indicate that the Solar System is an atypical member of the overall population of planetary systems. We report here on a strong anticorrelation of orbital eccentricity with multiplicity (number of planets in the system) among cataloged radial velocity (RV) systems. The mean, median, and rough distribution of eccentricities of Solar System planets fits an extrapolation of this anticorrelation to the eight-planet case rather precisely despite the fact that no more than two Solar System planets would be detectable with RV data comparable to that in the exoplanet sample. Moreover, even if regarded as a single or double planetary system, the Solar System lies in a reasonably heavily populated region of eccentricity-multiplicity space. Thus, the Solar System is not anomalous among known exoplanetary systems with respect to eccentricities when its multiplicity is taken into account. Specifically, as the multiplicity of a system increases, the eccentricity decreases roughly as a power law of index -1.20. A simple and plausible but ad hoc and model-dependent interpretation of this relationship implies that ∼ 80% of the one-planet and 25% of the two-planet systems in our sample have additional, as yet undiscovered, members but that systems of higher observed multiplicity are largely complete (i.e., relatively rarely contain additional undiscovered planets). If low eccentricities indeed favor high multiplicities, habitability may be more common in systems with a larger number of planets.

HABITABLE CLIMATES: THE INFLUENCE OF ECCENTRICITY

International Nuclear Information System (INIS)

Dressing, Courtney D.; Spiegel, David S.; Scharf, Caleb A.; Menou, Kristen; Raymond, Sean N.

2010-01-01

In the outer regions of the habitable zone, the risk of transitioning into a globally frozen 'snowball' state poses a threat to the habitability of planets with the capacity to host water-based life. Here, we use a one-dimensional energy balance climate model (EBM) to examine how obliquity, spin rate, orbital eccentricity, and the fraction of the surface covered by ocean might influence the onset of such a snowball state. For an exoplanet, these parameters may be strikingly different from the values observed for Earth. Since, for a constant semimajor axis, the annual mean stellar irradiation scales with (1 - e 2 ) -1/2 , one might expect the greatest habitable semimajor axis (for fixed atmospheric composition) to scale as (1 - e 2 ) -1/4 . We find that this standard simple ansatz provides a reasonable lower bound on the outer boundary of the habitable zone, but the influence of both obliquity and ocean fraction can be profound in the context of planets on eccentric orbits. For planets with eccentricity 0.5, for instance, our EBM suggests that the greatest habitable semimajor axis can vary by more than 0.8 AU (78%!) depending on obliquity, with higher obliquity worlds generally more stable against snowball transitions. One might also expect that the long winter at an eccentric planet's apoastron would render it more susceptible to global freezing. Our models suggest that this is not a significant risk for Earth-like planets around Sun-like stars, as considered here, since such planets are buffered by the thermal inertia provided by oceans covering at least 10% of their surface. Since planets on eccentric orbits spend much of their year particularly far from the star, such worlds might turnout to be especially good targets for direct observations with missions such as TPF-Darwin. Nevertheless, the extreme temperature variations achieved on highly eccentric exo-Earths raise questions about the adaptability of life to marginally or transiently habitable conditions.

Seismic analysis of a reactor building with eccentric layout

International Nuclear Information System (INIS)

Itoh, T.; Deng, D.Z.F.; Lui, K.

1987-01-01

Conventional design for a reactor building in a high seismic area has adopted an essentially concentric layout in response to fear of excessive torsional effect due to horizontal seismic load on an eccentric plant. This concentric layout requirement generally results in an inflexible arrangement of the plant facilities and thus increases the plant volume. This study is performed to investigate the effect of eccentricity on the overall seismic structural response and to provide technical information in this regard to substantiate the volume reduction of the overall power plant. The plant layout is evolved from the Bechtel standard plan of a PWR plant by integrating the reactor building and the auxiliary building into a combined building supported on a common basemat. This plant layout is optimized for volume utilization and to reduce the length of piping systems. The mass centers at various elevations of the combined building do not coincide with the rigidity center (RC) of the respective floor and the geometric center of the basemat, thus creating an eccentric response of the building in a seismic environment. Therefore, the torsional effects of the structure have to be taken into account in the seismic analysis

Lower-Bound Calculations of the Bearing Capacity of Eccentrically Loaded Footings in Cohesionless Soil

DEFF Research Database (Denmark)

Krabbenhøft, Sven; Damkilde, Lars; Krabbenhøft, Kristian

2012-01-01

Lower-bound calculations based on the finite element method are used to determine the bearing capacity of a strip foundation subjected to a vertical, eccentric load on cohesionless soil with varying surcharges. The soil is assumed perfectly plastic following the Mohr-Coulomb failure criterion. Th...

Skeletal Adaptations to Different Levels of Eccentric Resistance Following Eight Weeks of Training

Science.gov (United States)

English, Kirk L.; Loehr, James A.; Lee, Stuart M. C.; Maddocks, Mary J.; Laughlin, Mitzi S.; Hagan, R. Donald

2007-01-01

Coupled concentric-eccentric resistive exercise maintains bone mineral density (BMD) during bed rest and aging. PURPOSE: We hypothesized that 8 wks of lower body resistive exercise training with higher ratios of eccentric to concentric loading would enhance hip and lumbar BMD. METHODS: Forty untrained male volunteers (34.9+/-7.0 yrs, 80.9+/-9.8 kg, 178.2+/-7.1 cm; mean+/-SD) were matched for leg press (LP) 1-Repetition Maximum (1-RM) strength and randomly assigned to one of 5 training groups. Concentric load (% 1-RM) was constant across groups, but each group trained with different levels of eccentric load (0, 33, 66, 100, or 138% of concentric) for all training sessions. Subjects performed a periodized supine LP and heel raise (HR) training program 3 d wk-1 for 8 wks using a modified Agaton Fitness System (Agaton Fitness AB, Boden, Sweden). Hip and lumbar BMD (g/sq cm) was measured in triplicate pre- and post-training using DXA (Hologic Discovery ). Pre- and post-training means were compared using the appropriate ANOVA and Tukey's post hoc tests. Within group pre- to post-training BMD was compared using paired t-tests with a Bonferroni adjustment. RESULTS: There was a main effect of training on L1, L2, L3, L4, total lumbar, and greater trochanter BMD, but there were no differences between groups. CONCLUSION: Eights wks of lower body resistive exercise increased greater trochanter and lumbar BMD. Inability to detect group differences may have been influenced by a potentially osteogenic vibration associated with device operation in the 0, 33, and 66% groups.

Chain hexagonal cacti with the extremal eccentric distance sum.

Science.gov (United States)

Qu, Hui; Yu, Guihai

2014-01-01

Eccentric distance sum (EDS), which can predict biological and physical properties, is a topological index based on the eccentricity of a graph. In this paper we characterize the chain hexagonal cactus with the minimal and the maximal eccentric distance sum among all chain hexagonal cacti of length n, respectively. Moreover, we present exact formulas for EDS of two types of hexagonal cacti.

Eccentric binaries of compact objects in strong-field gravity

International Nuclear Information System (INIS)

Gold, Roman

2011-01-01

In this thesis we study the dynamics as well as the resulting gravitational radiation from eccentric binaries of compact objects in the non-linear regime of General Relativity. For this purpose we solve Einstein's field equation numerically in a 3+1 decomposition using the moving-puncture technique. We focus our study on very particular orbits, arising as a purely relativistic phenomenon of the two-body problem in General Relativity, which are associated with unstable circular orbits. They are governed by a fast, nearly circular revolution at a short distance followed by a slow, radial motion on a nearly elliptic trajectory. Due to the unique features of their orbital trajectories they are called zoom-whirl orbits. We analyze how the peculiar dynamics manifests itself in the emitted gravitational radiation and to which extent one can infer the orbital properties from observations of the gravitational waves. In the first part, we consider black hole binaries. We perform a comprehensive parameter study by varying the initial eccentricity, computing and characterizing the resulting gravitational waveforms. We address aspects, which can only be obtained from non-perturbative methods, and which are crucial to the astrophysical relevance of these orbits. In particular, our results imply a fairly low amount of fine-tuning necessary to spot zoom-whirl effects. We find whirl orbits for values of the eccentricities, which fall in disjunct intervals extending to rather low values. Furthermore, we show that whirl effects just before merger cause a signal with significant amplitude. In the second part, we investigate neutron star binaries on eccentric orbits in full General Relativity, which has not been studied so far. We explore their phenomenology and study the consequences for the matter after the neutron stars have merged. In these evolutions the merged neutron stars sooner or later collapse to form a black hole. During the collapse most of the matter is accreted on to the

Ultrasound-Guided Percutaneous Electrolysis and Eccentric Exercises for Subacromial Pain Syndrome: A Randomized Clinical Trial

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José L. Arias-Buría

2015-01-01

Full Text Available Objective. To compare effects of ultrasound- (US- guided percutaneous electrolysis combined with an eccentric exercise program of the rotator cuff muscles in subacromial pain syndrome. Methods. Thirty-six patients were randomized and assigned into US-guided percutaneous electrolysis (n=17 group or exercise (n=19 group. Patients were asked to perform an eccentric exercise program of the rotator cuff muscles twice every day for 4 weeks. Participants assigned to US-guided percutaneous electrolysis group also received the application of galvanic current through acupuncture needle on each session once a week (total 4 sessions. Shoulder pain (NPRS and disability (DASH were assessed at baseline, after 2 sessions, and 1 week after the last session. Results. The ANOVA revealed significant Group∗Time interactions for shoulder pain and disability (all, P<0.01: individuals receiving US-guided percutaneous electrolysis combined with the eccentric exercises experienced greater improvement than those receiving eccentric exercise alone. Conclusions. US-guided percutaneous electrolysis combined with eccentric exercises resulted in small better outcomes at short term compared to when only eccentric exercises were applied in subacromial pain syndrome. The effect was statistically and clinically significant for shoulder pain but below minimal clinical difference for function. Future studies should investigate the long-term effects and potential placebo effect of this intervention.

Formation of Close-in Super-Earths by Giant Impacts: Effects of Initial Eccentricities and Inclinations of Protoplanets

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Yuji [Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba, 275-0016 (Japan); Kokubo, Eiichiro, E-mail: ymatsumoto@cfca.nao.ac.jp [Center for Computational Astrophysics, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

2017-07-01

Recent observations have revealed the eccentricity and inclination distributions of close-in super-Earths. These distributions have the potential to constrain their formation processes. In the in situ formation scenario, the eccentricities and inclinations of planets are determined by gravitational scattering and collisions between protoplanets on the giant impact stage. We investigate the effect of the initial eccentricities and inclinations of protoplanets on the formation of close-in super-Earths. We perform N -body simulations of protoplanets in gas-free disks, changing the initial eccentricities and inclinations systematically. We find that while the eccentricities of protoplanets are well relaxed through their evolution, the inclinations are not. When the initial inclinations are small, they are not generally pumped up since scattering is less effective and collisions occur immediately after orbital crossing. On the other hand, when the initial inclinations are large, they tend to be kept large since collisional damping is less effective. Not only the resultant inclinations of planets, but also their number, eccentricities, angular momentum deficit, and orbital separations are affected by the initial inclinations of protoplanets.

Time Course and Association of Functional and Biochemical Markers in Severe Semitendinosus Damage Following Intensive Eccentric Leg Curls: Differences between and within Subjects

Directory of Open Access Journals (Sweden)

Gerard Carmona

2018-02-01

Full Text Available Purpose: To investigate the extent and evolution of hamstring muscle damage caused by an intensive bout of eccentric leg curls (ELCs by (1 assessing the time course and association of different indirect markers of muscle damage such as changes in the force-generating capacity (FGC, functional magnetic resonance (fMRI, and serum muscle enzyme levels and (2 analyzing differences in the degree of hamstring muscle damage between and within subjects (limb-to-limb comparison.Methods: Thirteen male participants performed six sets of 10 repetitions of an ELC with each leg. Before and at regular intervals over 7 days after the exercise, FGC was measured with maximal isometric voluntary contraction (MVC. Serum enzyme levels, fMRI transverse relaxation time (T2 and perceived muscle soreness were also assessed and compared against the FGC.Results: Two groups of subjects were identified according to the extent of hamstring muscle damage based on decreased FGC and increased serum enzyme levels: high responders (n = 10, severe muscle damage and moderate responders (n = 3, moderate muscle damage. In the high responders, fMRI T2 analysis revealed that the semitendinosus (ST muscle suffered severe damage in the three regions measured (proximal, middle, and distal. The biceps femoris short head (BFsh muscle was also damaged and there were significant differences in the FGC within subjects in the high responders.Conclusion: FGC and serum enzyme levels measured in 10 of the subjects from the sample were consistent with severe muscle damage. However, the results showed a wide range of peak MVC reductions, reflecting different degrees of damage between subjects (high and moderate responders. fMRI analysis confirmed that the ST was the hamstring muscle most damaged by ELCs, with uniform T2 changes across all the measured sections of this muscle. During intensive ELCs, the ST muscle could suffer an anomalous recruitment pattern due to fatigue and damage, placing an

Eccentricity dimension of the Dimensional Clinical Personality Inventory: Review and psychometric properties

OpenAIRE

Carvalho, Lucas de Francisco; Pianowski, Giselle; Silveira, Fernando José; Bacciotti, Jonatha Tiago; Vieira, Philipe Gomes

2016-01-01

Abstract We aimed to review of the Eccentricity dimension of the Dimensional Clinical Personality Inventory (IDCP), through two steps. The first one focused on developing new items and the second on testing the psychometric properties in a sample of 225 subjects (70.1% females), aging between 18 and 66 years, mostly undergraduate students (58.9%). The subjects answered the IDCP, and the Brazilian versions of the NEO-PI-R, PID-5 and MIS. The first step resulted in 42 items, which 22 were new. ...

Does intermittent pneumatic leg compression enhance muscle recovery after strenuous eccentric exercise?

Science.gov (United States)

Cochrane, D J; Booker, H R; Mundel, T; Barnes, M J

2013-11-01

Intermittent pneumatic compression (IPC) has gained rapid popularity as a post-exercise recovery modality. Despite its widespread use and anecdotal claims for enhancing muscle recovery there is no scientific evidence to support its use. 10 healthy, active males performed a strenuous bout of eccentric exercise (3 sets of 100 repetitions) followed by IPC treatment or control performed immediately after exercise and at 24 and 48 h post-exercise. Muscular performance measurements were taken prior to exercise and 24, 48 and 72 h post-exercise and included single-leg vertical jump (VJ) and peak and average isometric [knee angle 75º] (ISO), concentric (CON) and eccentric (ECC) contractions performed at slow (30° · s⁻¹) and fast (180° · s⁻¹) velocities. Plasma creatine kinase (CK) samples were taken at pre- and post-exercise 24, 48 and 72 h. Strenuous eccentric exercise resulted in a significant decrease in peak ISO, peak and average CON (30° · s⁻¹) at 24 h compared to pre-exercise for both IPC and control, however VJ performance remained unchanged. There were no significant differences between conditions (IPC and control) or condition-time interactions for any of the contraction types (ISO, CON, ECC) or velocities (CON, ECC 30° · s⁻¹ and 180° · s⁻¹). However, CK was significantly elevated at 24 h compared to pre-exercise in both conditions (IPC and control). IPC did not attenuate muscle force loss following a bout of strenuous eccentric exercise in comparison to a control. While IPC has been used in the clinical setting to treat pathologic conditions, the parameters used to treat muscle damage following strenuous exercise in healthy participants are likely to be very different than those used to treat pathologic conditions. © Georg Thieme Verlag KG Stuttgart · New York.

Eccentric exercise in treatment of Achilles tendinopathy.

Science.gov (United States)

Nørregaard, J; Larsen, C C; Bieler, T; Langberg, H

2007-04-01

Prognosis and treatment of Achilles tendon pain (achillodynia) has been insufficiently studied. The purpose of the present study was to examine the long-term effect of eccentric exercises compared with stretching exercises on patients with achillodynia. Patients with achillodynia for at least 3 months were randomly allocated to one of two exercise regimens. Exercise was performed daily for a 3-month period. Symptom severity was evaluated by tendon tenderness, ultrasonography, a questionnaire on pain and other symptoms, and a global assessment of improvement. Follow-up was performed at time points 3, 6, 9, 12 weeks and 1 year. Of 53 patients with achillodynia 45 patients were randomized to either eccentric exercises or stretching exercises. Symptoms gradually improved during the 1-year follow-up period and were significantly better assessed by pain and symptoms after 3 weeks and all later visits. However, no significant differences could be observed between the two groups. Women and patients with symptoms from the distal part of the tendon had significantly less improvement. Marked improvement in symptoms and findings could be gradually observed in both groups during the 1-year follow-up period. To that extent this is due to effect of both regimens or the spontaneous improvement is unsettled.

Driving dynamic colloidal assembly using eccentric self-propelled colloids

OpenAIRE

Ma, Zhan; Lei, Qun-li; Ni, Ran

2017-01-01

Designing protocols to dynamically direct the self-assembly of colloidal particles has become an important direction in soft matter physics because of the promising applications in fabrication of dynamic responsive functional materials. Here using computer simulations, we found that in the mixture of passive colloids and eccentric self-propelled active particles, when the eccentricity and self-propulsion of active particles are high enough, the eccentric active particles can push passive coll...

Numerical analysis of two pile caps with sockets embedded, subject the eccentric compression load

Directory of Open Access Journals (Sweden)

R. G. Delalibera

Full Text Available The structural behavior of pile caps with sockets embedded is influenced by interface of column-socket, which can be smooth or rough. With intent to analyze the behavior of two pile caps with embedded socket, considering the friction between the column and the socket, with eccentric normal load, the numerical simulations were carried out, using a program based on the Finite Element Methods (FEM. In the numerical analysis the non-linear behavior of materials was considered, also the friction between the column and the socket. It was considered perfect bond between the reinforcement and the concrete around. It was observed that the embedded length is preponderant factor in the structural behavior of the analyzed element.

The Effect of Eccentric Exercise-Induced Delayed-Onset Muscle Soreness on Positioning Sense and Shooting Percentage in Wheelchair Basketball Players

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Mehmet Akif Serinken

2013-12-01

Full Text Available Background: Eccentric exercise is defined as a type of exercise in which the muscle produces power by extending. In contrast to isometric and concentric exercises, eccentric muscle activity is much more effective mechanically; however, it may expose the muscle to soreness. Delayed-Onset Muscle Soreness (DOMS emerges a couple of hours after an eccentric activity, especially in individuals who are not used to this kind of exercise, and causes a temporary decrease in muscle performance, joint movement angle and muscle power, and also a temporary increase in the blood creatine kinase (CK activity. Aims: This study investigates the effect of DOMS on the upper extremities motor performance by conducting an eccentric exercise load on the elbow flexor muscles. Study design: Cross sectional study. Methods: The study included 10 wheelchair basketball players. First, the participants underwent blood CK activity, positioning sense, muscle pain, shooting performance measurements tests at the base, and after 30 minutes and 24 and 48 hours. Then, one week later, the one-repetition-maximums of biceps curls were determined in order to define the intensity of the eccentric exercise. An eccentric exercise protocol which would cause DOMS was applied to all players. All tests were replaced with acute exhaustive eccentric exercise; the same tests were repeated in the same order after the exercise. Blood CK activity was measured by taking an earlobe capillary blood sample. The muscle pain level was measured by using a Visual Analogue Scale (VAS. Positioning sense loss was assessed via goniometer at 30º, 60º and 90º degrees horizontally. Results: The study found a statistically significant increase in blood CK activity and positioning sense loss, and a decrease in the pressure-pain threshold, as well as the shooting percentages in the exercise group when compared with the control. Conclusion: These findings suggest that DOMS negatively affects the upper extremities

Caffeine-induced increase in voluntary activation and strength of the quadriceps muscle during isometric, concentric and eccentric contractions.

Science.gov (United States)

Behrens, Martin; Mau-Moeller, Anett; Weippert, Matthias; Fuhrmann, Josefin; Wegner, Katharina; Skripitz, Ralf; Bader, Rainer; Bruhn, Sven

2015-05-13

This study investigated effects of caffeine ingestion (8 mg/kg) on maximum voluntary torque (MVT) and voluntary activation of the quadriceps during isometric, concentric and eccentric contractions. Fourteen subjects ingested caffeine and placebo in a randomized, controlled, counterbalanced, double-blind crossover design. Neuromuscular tests were performed before and 1 h after oral caffeine and placebo intake. MVTs were measured and the interpolated twitch technique was applied during isometric, concentric and eccentric contractions to assess voluntary activation. Furthermore, normalized root mean square of the EMG signal was calculated and evoked spinal reflex responses (H-reflex evoked at rest and during weak isometric voluntary contraction) as well as twitch torques were analyzed. Caffeine increased MVT by 26.4 N m (95%CI: 9.3-43.5 N m, P = 0.004), 22.5 N m (95%CI: 3.1-42.0 N m, P = 0.025) and 22.5 N m (95%CI: 2.2-42.7 N m, P = 0.032) for isometric, concentric and eccentric contractions. Strength enhancements were associated with increases in voluntary activation. Explosive voluntary strength and voluntary activation at the onset of contraction were significantly increased following caffeine ingestion. Changes in spinal reflex responses and at the muscle level were not observed. Data suggest that caffeine ingestion induced an acute increase in voluntary activation that was responsible for the increased strength regardless of the contraction mode.

The heat shock protein response following eccentric exercise in human skeletal muscle is unaffected by local NSAID infusion

DEFF Research Database (Denmark)

Mikkelsen, U R; Paulsen, G; Schjerling, P

2013-01-01

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely consumed in relation to pain and injuries in skeletal muscle, but may adversely affect muscle adaptation probably via inhibition of prostaglandin synthesis. Induction of heat shock proteins (HSP) represents an important adaptive response...... in muscle subjected to stress, and in several cell types including cardiac myocytes prostaglandins are important in induction of the HSP response. This study aimed to determine the influence of NSAIDs on the HSP response to eccentric exercise in human skeletal muscle. Healthy males performed 200 maximal...

Normative values of eccentric hip abduction strength in novice runners

DEFF Research Database (Denmark)

Ramskov, D; Pedersen, M B; Kastrup, K

2014-01-01

normative values of maximal eccentric hip abduction strength in novice runners. METHODS: Novice healthy runners (n = 831) were recruited through advertisements at a hospital and a university. Maximal eccentric hip abduction strength was measured with a hand-held dynamometer. The demographic variables...... was found, p values were identified using a regression equation adjusting for age and gender. Based on this, the equation to calculate normative values for relative eccentric hip abduction strength became: (1.600 + (age * -0.005) + (gender (1 = male / 0 = female) * 0.215) ± 1 or 2 * 0......PURPOSE: Low eccentric strength of the hip abductors, might increase the risk of patellofemoral pain syndrome and iliotibial band syndrome in runners. No normative values for maximal eccentric hip abduction strength have been established. Therefore the purpose of this study was to establish...

Funny walking : the rise, fall and rise of the Anglo-American comic eccentric dancer

OpenAIRE

Wilkie, I

2017-01-01

This article will attempt to reposition comic eccentric dance as a metamorphic form that still, surprisingly, exists, and is to be found with reasonable ubiquity, in renewed incarna-tions within twenty first century media. \\ud Tracing the origins of comic eccentric dance through examples of earlier comedy performance, and drawing from Bergson’s comic theory of body misalliance, this article will dis-cuss this particularly ludic fusion of music and comedy. Further changes to the form affected ...

Response of electrostatic probes to eccentric charge distributions

DEFF Research Database (Denmark)

Johansson, Torben; McAllister, Iain Wilson

2001-01-01

The response of an electrostatic probe mounted in an electrode is examined with reference to eccentric charge distributions. The study involves using the probe λ function to derive a characteristic parameter. This parameter enables the response of the probe to different degrees of eccentricity...

Eccentric binaries of compact objects in strong-field gravity

Energy Technology Data Exchange (ETDEWEB)

Gold, Roman

2011-09-27

In this thesis we study the dynamics as well as the resulting gravitational radiation from eccentric binaries of compact objects in the non-linear regime of General Relativity. For this purpose we solve Einstein's field equation numerically in a 3+1 decomposition using the moving-puncture technique. We focus our study on very particular orbits, arising as a purely relativistic phenomenon of the two-body problem in General Relativity, which are associated with unstable circular orbits. They are governed by a fast, nearly circular revolution at a short distance followed by a slow, radial motion on a nearly elliptic trajectory. Due to the unique features of their orbital trajectories they are called zoom-whirl orbits. We analyze how the peculiar dynamics manifests itself in the emitted gravitational radiation and to which extent one can infer the orbital properties from observations of the gravitational waves. In the first part, we consider black hole binaries. We perform a comprehensive parameter study by varying the initial eccentricity, computing and characterizing the resulting gravitational waveforms. We address aspects, which can only be obtained from non-perturbative methods, and which are crucial to the astrophysical relevance of these orbits. In particular, our results imply a fairly low amount of fine-tuning necessary to spot zoom-whirl effects. We find whirl orbits for values of the eccentricities, which fall in disjunct intervals extending to rather low values. Furthermore, we show that whirl effects just before merger cause a signal with significant amplitude. In the second part, we investigate neutron star binaries on eccentric orbits in full General Relativity, which has not been studied so far. We explore their phenomenology and study the consequences for the matter after the neutron stars have merged. In these evolutions the merged neutron stars sooner or later collapse to form a black hole. During the collapse most of the matter is accreted on

Load eccentricity effects on behavior of circular footings reinforced with geogrid sheets

Directory of Open Access Journals (Sweden)

Ehsan Badakhshan

2015-12-01

Full Text Available In this paper, an experimental study for an eccentrically loaded circular footing, resting on a geogrid reinforced sand bed, is performed. To achieve this aim, the steel model footing of 120 mm in diameter and sand in relative density of 60% are used. Also, the effects of depth of first and second geogrid layers and number of reinforcement layers (1–4 on the settlement-load response and tilt of footing under various load eccentricities (0 cm, 0.75 cm, 1.5 cm, 2.25 cm and 3 cm are investigated. Test results indicate that ultimate bearing capacity increases in comparison with unreinforced condition. It is observed that when the reinforcements are placed in the optimum embedment depth (u/D = 0.42 and h/D = 0.42, the bearing capacity ratio (BCR increases with increasing load eccentricity to the core boundary of footing, and that with further increase of load eccentricity, the BCR decreases. Besides, the tilt of footing increases linearly with increasing settlement. Finally, by reinforcing the sand bed, the tilt of footing decreases at 2 layers of reinforcement and then increases by increasing the number of reinforcement layers.

Macular pigment optical density spatial distribution measured in a subject with oculocutaneous albinism.

Science.gov (United States)

Putnam, Christopher M; Bland, Pauline J

2014-01-01

Previous studies of macular pigment optical density (MPOD) distribution in individuals with oculocutaneous albinism (OCA) have primarily used objective measurement techniques including fundus reflectometry and autofluorescence. We report here on a subject with OCA and their corresponding MPOD distribution assessed through heterochromatic flicker photometry (HFP). A subject with a history of OCA presented with an ocular history including strabismus surgery of the LE with persistent amblyopia and mild, latent nystagmus. Best corrected visual acuity was 20/25- RE and 20/40- LE. Spectral domain optical coherence tomography (SD-OCT) and fundus photography were also obtained. Evaluation of MPOD spatial distribution up to 8 degrees eccentricity from the fovea was performed using HFP. SD-OCT indicated a persistence of multiple inner retinal layers within the foveal region in the RE and LE including symmetric foveal thickening consistent with foveal hypoplasia. Fundus photography showed mild retinal pigmented epithelial (RPE) hypopigmentation and a poorly demarcated macula. OriginPro 9 was used to plot MPOD spatial distribution of the subject and a 33-subject sample. The OCA subject demonstrated a foveal MPOD of 0.10 with undetectable levels at 6 degrees eccentricity. The study sample showed a mean foveal MPOD of 0.34 and mean 6 degree eccentricity values of 0.03. Consistent with previous macular pigment (MP) studies of OCA, overall MPOD is reduced in our subject. Mild phenotypic expression of OCA with high functional visual acuity may represent a Henle fiber layer amenable to additional MP deposition. Further study of MP supplementation in OCA patients is warranted. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Greater Strength Gains after Training with Accentuated Eccentric than Traditional Isoinertial Loads in Already Strength-Trained Men

Science.gov (United States)

Walker, Simon; Blazevich, Anthony J.; Haff, G. Gregory; Tufano, James J.; Newton, Robert U.; Häkkinen, Keijo

2016-01-01

As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading vs. traditional isoinertial resistance training in strength-trained men. Young (22 ± 3 years, 177 ± 6 cm, 76 ± 10 kg, n = 28) strength-trained men (2.6 ± 2.2 years experience) were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%) or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle) and isokinetic (concentric and eccentric 30°.s−1) knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasonography and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18 ± 10 vs. 1 ± 5%, p < 0.01), which was accompanied by an increase in voluntary activation (3.5 ± 5%, p < 0.05). Isokinetic eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p < 0.05), whereas concentric torque

Brain activation associated with eccentric movement: A narrative review of the literature.

Science.gov (United States)

Perrey, Stéphane

2018-02-01

The movement occurring when a muscle exerts tension while lengthening is known as eccentric muscle action. Literature contains limited evidence on how our brain controls eccentric movement. However, how the cortical regions in the motor network are activated during eccentric muscle actions may be critical for understanding the underlying control mechanism of eccentric movements encountered in daily tasks. This is a novel topic that has only recently begun to be investigated through advancements in neuroimaging methods (electroencephalography, EEG; functional magnetic resonance imaging, fMRI). This review summarizes a selection of seven studies indicating mainly: longer time and higher cortical signal amplitude (EEG) for eccentric movement preparation and execution, greater magnitude of cortical signals with wider activated brain area (EEG, fMRI), and weaker brain functional connectivity (fMRI) between primary motor cortex (M1) and other cortical areas involved in the motor network during eccentric muscle actions. Only some differences among studies due to the forms of movement with overload were observed in the contralateral (to the active hand) M1 activity during eccentric movement. Altogether, the findings indicate an important challenge to the brain for controlling the eccentric movement. However, our understanding remains limited regarding the acute effects of eccentric exercise on cortical regions and their cooperation as functional networks that support motor functions. Further analysis and standardized protocols will provide deeper insights into how different cortical regions of the underlying motor network interplay with each other in increasingly demanding muscle exertions in eccentric mode.

Effects of 12-wk eccentric calf muscle training on muscle-tendon glucose uptake and SEMG in patients with chronic Achilles tendon pain

DEFF Research Database (Denmark)

Masood, Tahir; Kalliokoski, Kari; Magnusson, S Peter

2014-01-01

High-load eccentric exercises have been a key component in the conservative management of chronic Achilles tendinopathy. This study investigated the effects of a 12-wk progressive, home-based eccentric rehabilitation program on ankle plantar flexors' glucose uptake (GU) and myoelectric activity......, while the asymptomatic leg displayed higher uptake for medial gastrocnemius and flexor hallucis longus (P tendon GU than the controls (P effect on the tendon GU. Concerning SEMG, at baseline, soleus showed more relative...... within- or between-group differences. Eccentric rehabilitation was effective in decreasing subjective severity of Achilles tendinopathy. It also resulted in redistribution of relative electrical activity, but not metabolic activity, within the triceps surae muscle....

Design and jump phenomenon analysis of an eccentric ring energy harvester

International Nuclear Information System (INIS)

Wang, Yu-Jen; Chen, Chung-De

2013-01-01

This paper presents the development of a wheel-mounted eccentric ring energy harvester that is driven by centripetal and gravitational forces during wheel rotation. The natural frequency of the eccentric ring matches the wheel rotation frequency at any car speed because its character length is designed equal to the wheel radius. Consequently, the eccentric ring oscillates with a relatively large swing angle at the wheel speed to generate high levels of power. The nonlinear dynamic behavior of the eccentric ring is investigated to ensure that the proposed design produces steady swing angles, especially at high wheel speeds. Herein, the jump phenomenon of the dynamic motion of the eccentric ring is analyzed by using the Duffing equation and the linearization process. The discriminant value obtained from the analysis confirms that no jump phenomenon occurs at all wheel speeds if the eccentric ring is properly designed. In the experiment, the eccentric ring is integrated with magnets and a coil set to generate 318–442 μW at constant wheel speeds between 300 and 500 rpm. This shows that the proposed device is a potential power source for low-power wheel-mounted electronics, such as pressure sensors, accelerometers, and thermometers. (paper)

Design and jump phenomenon analysis of an eccentric ring energy harvester

Science.gov (United States)

Wang, Yu-Jen; Chen, Chung-De

2013-10-01

This paper presents the development of a wheel-mounted eccentric ring energy harvester that is driven by centripetal and gravitational forces during wheel rotation. The natural frequency of the eccentric ring matches the wheel rotation frequency at any car speed because its character length is designed equal to the wheel radius. Consequently, the eccentric ring oscillates with a relatively large swing angle at the wheel speed to generate high levels of power. The nonlinear dynamic behavior of the eccentric ring is investigated to ensure that the proposed design produces steady swing angles, especially at high wheel speeds. Herein, the jump phenomenon of the dynamic motion of the eccentric ring is analyzed by using the Duffing equation and the linearization process. The discriminant value obtained from the analysis confirms that no jump phenomenon occurs at all wheel speeds if the eccentric ring is properly designed. In the experiment, the eccentric ring is integrated with magnets and a coil set to generate 318-442 μW at constant wheel speeds between 300 and 500 rpm. This shows that the proposed device is a potential power source for low-power wheel-mounted electronics, such as pressure sensors, accelerometers, and thermometers.

Lengthening our perspective: morphological, cellular, and molecular responses to eccentric exercise.

Science.gov (United States)

Hyldahl, Robert D; Hubal, Monica J

2014-02-01

The response of skeletal muscle to unaccustomed eccentric exercise has been studied widely, yet it is incompletely understood. This review is intended to provide an up-to-date overview of our understanding of how skeletal muscle responds to eccentric actions, with particular emphasis on the underlying molecular and cellular mechanisms of damage and recovery. This review begins by addressing the question of whether eccentric actions result in physical damage to muscle fibers and/or connective tissue. We next review the symptomatic manifestations of eccentric exercise (i.e., indirect damage markers, such as delayed onset muscle soreness), with emphasis on their relatively poorly understood molecular underpinnings. We then highlight factors that potentially modify the muscle damage response following eccentric exercise. Finally, we explore the utility of using eccentric training to improve muscle function in populations of healthy and aging individuals, as well as those living with neuromuscular disorders. Copyright © 2013 Wiley Periodicals, Inc.

Flexibility training and the repeated-bout effect: priming interventions prior to eccentric training of the knee flexors.

Science.gov (United States)

Leslie, Andrew W; Lanovaz, Joel L; Andrushko, Justin W; Farthing, Jonathan P

2017-10-01

Both the repeated-bout effect and increased flexibility have been linked to reduced muscle damage, fatigue, and strength loss after intense eccentric exercise. Our purpose was to compare the eccentric-training (ECC) response after first priming the muscles with either static flexibility training or a single intense bout of eccentric exercise. Twenty-five participants were randomly assigned to flexibility training (n = 8; 3×/week; 30 min/day), a single bout of intense eccentric exercise (n = 9), or no intervention (control; n = 8) during a 4-week priming phase, prior to completing a subsequent 4-week period of eccentric training of the knee flexors. Testing was completed prior to the priming phase, before ECC, during acute ECC (0 h, 24 h, and 48 h after bouts 1 and 4), and after ECC. Measures included muscle thickness (MT; via ultrasound); isometric, concentric, and eccentric strength; muscle power (dynamometer); electromyography; range of motion; optimal angle of peak torque; and soreness (visual analog scale). Flexibility training and single-bout groups had 47% less soreness at 48 h after the first bout of ECC compared with control (p training group had 10% less soreness at 48 h after the fourth ECC bout compared with both the single-bout and control groups (p training group (-9%) after the fourth ECC bout compared with control (-19%; p training may be more effective than a single session of eccentric exercise in reducing adverse symptoms during the acute stages of eccentric training; however, these benefits did not translate into greater performance after training.

Eccentric Exercises Reduce Hamstring Strains in Elite Adult Male Soccer Players: A Critically Appraised Topic.

Science.gov (United States)

Shadle, Ian B; Cacolice, Paul A

2017-11-01

Clinical Scenario: Hamstring strains are a common sport-related injury, which may limit athletic performance for an extended period of time. These injuries are common in the soccer setting. As such, it is important to determine an appropriate prevention program to minimize the risk of such an injury for these athletes. Eccentric hamstring training may be an effective and practical hamstring strain prevention strategy. What is the effect of eccentric exercises on hamstring strain prevention in adult male soccer players? Summary of Key Findings: Current literature was searched for studies of level 2 evidence or higher that investigated the effect of eccentric exercises in preventing hamstring strains in adult male soccer players. Three articles returned from the literature search met the inclusion criteria. A fourth article looked at differences in strength gains between eccentric and concentric hamstring strengthening exercises, but did not record hamstring strain incidence. A fifth article, a systematic review, met all the criteria except for the correct population. Of the 3 studies, 2 were randomized control trails and 1 was a cohort study. Clinical Bottom Line: There is robust supportive evidence that eccentric hamstring exercises can prevent a hamstring injury to an elite adult male soccer player. Therefore, it is recommended that athletic trainers and other sports medicine providers evaluate current practices relating to reducing hamstring strains and consider implementing eccentric exercise based prevention programs. Strength of Recommendation: All evidence was attained from articles with a level of evidence 2b or higher, based on the Center for Evidence-Based Medicine (CEBM) criteria, stating that eccentric exercises can decrease hamstring strains.

RESONANT POST-NEWTONIAN ECCENTRICITY EXCITATION IN HIERARCHICAL THREE-BODY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Naoz, Smadar; Kocsis, Bence; Loeb, Abraham [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yunes, Nicolas, E-mail: snaoz@cfa.harvard.edu [Department of Physics, Montana State University, Bozeman, MT 59718 (United States)

2013-08-20

We study the secular, hierarchical three-body problem to first-order in a post-Newtonian expansion of general relativity (GR). We expand the first-order post-Newtonian Hamiltonian to leading-order in the ratio of the semi-major axis of the two orbits. In addition to the well-known terms that correspond to the GR precession of the inner and outer orbits, we find a new secular post-Newtonian interaction term that can affect the long-term evolution of the triple. We explore the parameter space for highly inclined and eccentric systems, where the Kozai-Lidov mechanism can produce large-amplitude oscillations in the eccentricities. The standard lore, i.e., that GR effects suppress eccentricity, is only consistent with the parts of phase space where the GR timescales are several orders of magnitude shorter than the secular Newtonian one. In other parts of phase space, however, post-Newtonian corrections combined with the three-body ones can excite eccentricities. In particular, for systems where the GR timescale is comparable to the secular Newtonian timescales, the three-body interactions give rise to a resonant-like eccentricity excitation. Furthermore, for triples with a comparable-mass inner binary, where the eccentric Kozai-Lidov mechanism is suppressed, post-Newtonian corrections can further increase the eccentricity and lead to orbital flips even when the timescale of the former is much longer than the timescale of the secular Kozai-Lidov quadrupole perturbations.

Improving the seismic performance of eccentrically braced frames by using a ductile element

OpenAIRE

Morteza Naghipour; Seyed Reza Salim Bahrami

2017-01-01

Stability of structures against earthquake is much important to prevent total or partial failure of structures and loss of financial and human investments of people and country. Eccentrically braced frames, as one of the most commonly used earthquake resistant systems, with good ductility and toughness, have different arrangements; one of them is Link beam-to-column connection. This type of connection was considered as bending form before the North Ridge earthquake (1994). But conducted resea...

Pervasive orbital eccentricities dictate the habitability of extrasolar earths.

Science.gov (United States)

Kita, Ryosuke; Rasio, Frederic; Takeda, Genya

2010-09-01

The long-term habitability of Earth-like planets requires low orbital eccentricities. A secular perturbation from a distant stellar companion is a very important mechanism in exciting planetary eccentricities, as many of the extrasolar planetary systems are associated with stellar companions. Although the orbital evolution of an Earth-like planet in a stellar binary system is well understood, the effect of a binary perturbation on a more realistic system containing additional gas-giant planets has been very little studied. Here, we provide analytic criteria confirmed by a large ensemble of numerical integrations that identify the initial orbital parameters leading to eccentric orbits. We show that an extrasolar earth is likely to experience a broad range of orbital evolution dictated by the location of a gas-giant planet, which necessitates more focused studies on the effect of eccentricity on the potential for life.

Conformation radiotherapy with eccentric multi-leaves, (1)

International Nuclear Information System (INIS)

Obata, Yasunori; Sakuma, Sadayuki.

1986-01-01

In order to extend the application of the conformation radiotherapy, the eccentric multi-leaves are equipped with the linear accelerator. The information of the position of the collimators and the dose distribution of the eccentric conformation radiotherapy are calculated by the improved algorism of the treatment planning system. In simple cases, the dose distributions for the distant region from the rotational center are measured and compared with the calculated values. Both distributions are well coincided with the error of about 5 % in the high dose region and 10 % in the low dose region. In eccentric conformation radiotherapy, it is difficult to deliver the planned dose to the lesion. The dose increases with the distance of the target area from the rotational center. And the measured value and the calculated value are well coincided with 1 % error. So after getting the dose ratio of the rotational center to the target area, the calculated dose can be delivered to the rotational center. The advantages of the eccentric conformation radiotherapy are a good coincidence of target area and treated area, a partial shielding and a hollow out technique without absorber. The limitation of the movement of the collimator from center is 5 cm at 1 m SCD. (author)

Tidal Disruption Events from Eccentric Nuclear Disks

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Wernke, Heather N.; Madigan, Ann-Marie

2018-04-01

Stars that get too close to a supermassive black hole are in danger of being tidally disrupted. Stellar two-body relaxation is commonly assumed to be the main driver of these events. Recent work has shown, however, that secular gravitational torques from eccentric nuclear disks can push stars to extreme eccentricities at much higher rates than predicted by two-body relaxation. This work did not include the effects of general relativity, however, which could quench secular torques via rapid apsidal precession. Here we show that, for a star in danger of disruption, general relativity acts on a timescale of less than an orbital period. This short timescale means that general relativity does not have enough time to have a major effect on the orbit. When driven by secular torques from eccentric nuclear disks, tidal disruption event rates are not affected by general relativity.

Achilles tendon of wistar rats treated with laser therapy and eccentric exercise

OpenAIRE

Souza, Maria Verônica de; Silva, Carlos Henrique Osório; Silva, Micheline Ozana da; Costa, Marcela Bueno Martins da; Dornas, Raul Felipe; Borges, Andréa Pacheco Batista; Natali, Antônio José

2015-01-01

ABSTRACTIntroduction:Both laser therapy and eccentric exercises are used in tendon injuries. However, the association of these physiotherapeutic modalities is yet little investigated.Objective:To evaluate the effect of low-level laser therapy associated to eccentric exercise (downhill walking) on Achilles tendinopathy of Wistar rats.Method:Eighteen Achilles tendon from 15 adult male Wistar rats were used. Tendons were distributed in six groups (laser, eccentric exercise, laser and eccentric e...

Comparing the effects of eccentric training with eccentric training and static stretching exercises in the treatment of patellar tendinopathy. A controlled clinical trial.

Science.gov (United States)

Dimitrios, Stasinopoulos; Pantelis, Manias; Kalliopi, Stasinopoulou

2012-05-01

The aim of the present study was to investigate the effectiveness of eccentric training and eccentric training with static stretching exercises in the management of patellar tendinopathy. Controlled clinical trial. Rheumatology and rehabilitation centre. Forty-three patients who had patellar tendinopathy for at least three months. They were allocated to two groups by alternative allocation. Group A (n = 22) was treated with eccentric training of patellar tendon and static stretching exercises of quadriceps and hamstrings and Group B (n = 21) received eccentric training of patellar tendon. All patients received five treatments per week for four weeks. Pain and function were evaluated using the VISA-P score at baseline, at the end of treatment (week 4), and six months (week 24) after the end of treatment. At the end of treatment, there was a rise in VISA-P score in both groups compared with baseline (Peccentric training and static stretching exercises produced the largest effect (PEccentric training and static stretching exercises is superior to eccentric training alone to reduce pain and improve function in patients with patellar tendinopathy at the end of the treatment and at follow-up.

Eccentric exercise in treatment of Achilles tendinopathy

DEFF Research Database (Denmark)

Nørregaard, J; Larsen, C C; Bieler, T

2007-01-01

Prognosis and treatment of Achilles tendon pain (achillodynia) has been insufficiently studied. The purpose of the present study was to examine the long-term effect of eccentric exercises compared with stretching exercises on patients with achillodynia.......Prognosis and treatment of Achilles tendon pain (achillodynia) has been insufficiently studied. The purpose of the present study was to examine the long-term effect of eccentric exercises compared with stretching exercises on patients with achillodynia....

Achilles tendon of wistar rats treated with laser therapy and eccentric exercise

Directory of Open Access Journals (Sweden)

Maria Verônica de Souza

2015-10-01

Full Text Available ABSTRACTIntroduction:Both laser therapy and eccentric exercises are used in tendon injuries. However, the association of these physiotherapeutic modalities is yet little investigated.Objective:To evaluate the effect of low-level laser therapy associated to eccentric exercise (downhill walking on Achilles tendinopathy of Wistar rats.Method:Eighteen Achilles tendon from 15 adult male Wistar rats were used. Tendons were distributed in six groups (laser, eccentric exercise, laser and eccentric exercise, rest, contralateral tendon, and healthy tendon. Unilateral tendinopathy was surgically induced by transversal compression followed by scarification of tendon fibers. The treatments laser therapy (904 nm, 3J/cm² and/or eccentric exercise (downhill walking; 12 m/min; 50 min/day; 15o inclination treadmill began 24 hours after surgery and remained for 20 days. Clinical and biomechanical analyzes were conducted. Achilles tendon was macroscopically evaluated and the transversal diameter measured. Euthanasia was performed 21 days after lesion induction. Tendons of both limbs were collected and frozen at -20°C until biomechanical analysis, on which the characteristic of maximum load (N, stress at ultimate (MPa and maximum extension (mm were analyzed.Results:Swelling was observed within 72 hours postoperative. No fibrous adhesions were observed nor increase in transversal diameter of tendons. Animals with the exercised tendons, but not treated with laser therapy, presented lower (p=0.0000 locomotor capacity. No difference occurred be-tween groups for the biomechanical characteristics maximum load (p=0.4379, stress at ultimate (p=0.4605 and maximum extension (p=0.3820 evaluated, even considering healthy and contralateral tendons.Conclusion:The concomitant use of low-level laser and the eccentric exercise of downhill walking, starting 24 hours after surgically induced tendinopathy, do not result in a tendon with the same biomechanical resistance or elasticity

Complete waveform model for compact binaries on eccentric orbits

Science.gov (United States)

Huerta, E. A.; Kumar, Prayush; Agarwal, Bhanu; George, Daniel; Schive, Hsi-Yu; Pfeiffer, Harald P.; Haas, Roland; Ren, Wei; Chu, Tony; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela

2017-01-01

We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are nonspinning, and which evolve on orbits with low to moderate eccentricity. The inspiral evolution is described using third-order post-Newtonian equations both for the equations of motion of the binary, and its far-zone radiation field. This latter component also includes instantaneous, tails and tails-of-tails contributions, and a contribution due to nonlinear memory. This framework reduces to the post-Newtonian approximant TaylorT4 at third post-Newtonian order in the zero-eccentricity limit. To improve phase accuracy, we also incorporate higher-order post-Newtonian corrections for the energy flux of quasicircular binaries and gravitational self-force corrections to the binding energy of compact binaries. This enhanced prescription for the inspiral evolution is combined with a fully analytical prescription for the merger-ringdown evolution constructed using a catalog of numerical relativity simulations. We show that this inspiral-merger-ringdown waveform model reproduces the effective-one-body model of Ref. [Y. Pan et al., Phys. Rev. D 89, 061501 (2014)., 10.1103/PhysRevD.89.061501] for quasicircular black hole binaries with mass ratios between 1 to 15 in the zero-eccentricity limit over a wide range of the parameter space under consideration. Using a set of eccentric numerical relativity simulations, not used during calibration, we show that our new eccentric model reproduces the true features of eccentric compact binary coalescence throughout merger. We use this model to show that the gravitational-wave transients GW150914 and GW151226 can be effectively recovered with template banks of quasicircular, spin-aligned waveforms if the eccentricity e0 of these systems when they enter the aLIGO band at a gravitational-wave frequency of 14 Hz satisfies e0GW 150914≤0.15 and e0GW 151226≤0.1 . We also find that varying the spin

Orbital Eccentricity and the Stability of Planets in the Alpha Centauri System

Science.gov (United States)

Lissauer, Jack

2016-01-01

Planets on initially circular orbits are typically more dynamically stable than planets initially having nonzero eccentricities. However, the presence of a major perturber that forces periodic oscillations of planetary eccentricity can alter this situation. We investigate the dependance of system lifetime on initial eccentricity for planets orbiting one star within the alpha Centauri system. Our results show that initial conditions chosen to minimize free eccentricity can substantially increase stability compared to planets on circular orbits.

The effects of a repeated bout of eccentric exercise on indices of muscle damage and delayed onset muscle soreness.

Science.gov (United States)

Paddon-Jones, D; Muthalib, M; Jenkins, D

2000-03-01

This study examined markers of muscle damage following a repeated bout of maximal isokinetic eccentric exercise performed prior to full recovery from a previous bout. Twenty non-resistance trained volunteers were randomly assigned to a control (CON, n=10) or experimental (EXP, n=10) group. Both groups performed 36 maximal isokinetic eccentric contractions of the elbow flexors of the non-dominant arm (ECC1). The EXP group repeated the same eccentric exercise bout two days later (ECC2). Total work and peak eccentric torque were recorded during each set of ECC1 and ECC2. Isometric torque, delayed onset muscle soreness (DOMS), flexed elbow angle and plasma creatine kinase (CK) activity were measured prior to and immediately following ECC1 and ECC2. at 24h intervals for 7 days following ECC1 and finally on day 11. In both groups, all dependent variables changed significantly during the 2 days following ECC1. A further acute post-exercise impairment in isometric torque (30 +/- 5%) and flexed elbow angle (20 +/- 4%) was observed following ECC2 (p0.05). These findings suggest that when maximal isokinetic eccentric exercise is repeated two days after experiencing of contraction-induced muscle damage, the recovery time course is not significantly altered.

Normative values of eccentric hip abduction strength in novice runners

DEFF Research Database (Denmark)

Jørgensen, Daniel Ramskov; Pedersen, Mette Broen; Kastrup, Kristrian

2014-01-01

.354) Nm/kg. CONCLUSION: Normative values for maximal eccentric hip abduction strength in novice runners can be calculated by taking into account the differences in strength across genders and the decline in strength that occurs with increasing age. Age and gender were associated with maximal eccentric hip...... associated with maximal eccentric hip abduction strength from a univariate analysis were included in a multivariate linear regression model. Based on the results from the regression model, a regression equation for normative hip abduction strength is presented. RESULTS: A SIGNIFICANT DIFFERENCE IN MAXIMAL...... was found, p gender. Based on this, the equation to calculate normative values for relative eccentric hip abduction strength became: (1.600 + (age * -0.005) + (gender (1 = male / 0 = female) * 0.215) ± 1 or 2 * 0...

Image Analysis of Eccentric Photorefraction

Directory of Open Access Journals (Sweden)

J. Dušek

2004-01-01

Full Text Available This article deals with image and data analysis of the recorded video-sequences of strabistic infants. It describes a unique noninvasive measuring system based on two measuring methods (position of I. Purkynje image with relation to the centre of the lens and eccentric photorefraction for infants. The whole process is divided into three steps. The aim of the first step is to obtain video sequences on our special system (Eye Movement Analyser. Image analysis of the recorded sequences is performed in order to obtain curves of basic eye reactions (accommodation and convergence. The last step is to calibrate of these curves to corresponding units (diopter and degrees of movement.

The association of lesion eccentricity with plaque morphology and components in the superficial femoral artery: a high-spatial-resolution, multi-contrast weighted CMR study

Directory of Open Access Journals (Sweden)

Zhao Xihai

2010-07-01

Full Text Available Abstract Background Atherosclerotic plaque morphology and components are predictors of subsequent cardiovascular events. However, associations of plaque eccentricity with plaque morphology and plaque composition are unclear. This study investigated associations of plaque eccentricity with plaque components and morphology in the proximal superficial femoral artery using cardiovascular magnetic resonance (CMR. Methods Twenty-eight subjects with an ankle-brachial index less than 1.00 were examined with 1.5T high-spatial-resolution, multi-contrast weighted CMR. One hundred and eighty diseased locations of the proximal superficial femoral artery (about 40 mm were analyzed. The eccentric lesion was defined as [(Maximum wall thickness- Minimum wall thickness/Maximum wall thickness] ≥ 0.5. The arterial morphology and plaque components were measured using semi-automatic image analysis software. Results One hundred and fifteen locations were identified as eccentric lesions and sixty-five as concentric lesions. The eccentric lesions had larger wall but similar lumen areas, larger mean and maximum wall thicknesses, and more calcification and lipid rich necrotic core, compared to concentric lesions. For lesions with the same lumen area, the degree of eccentricity was associated with an increased wall area. Eccentricity (dichotomous as eccentric or concentric was independently correlated with the prevalence of calcification (odds ratio 3.78, 95% CI 1.47-9.70 after adjustment for atherosclerotic risk factors and wall area. Conclusions Plaque eccentricity is associated with preserved lumen size and advanced plaque features such as larger plaque burden, more lipid content, and increased calcification in the superficial femoral artery.

Analysis and optimization of dynamic model of eccentric shaft grinder

Science.gov (United States)

Gao, Yangjie; Han, Qiushi; Li, Qiguang; Peng, Baoying

2018-04-01

Eccentric shaft servo grinder is the core equipment in the process chain of machining eccentric shaft. The establishment of the movement model and the determination of the kinematic relation of the-axis in the grinding process directly affect the quality of the grinding process, and there are many error factors in grinding, and it is very important to analyze the influence of these factors on the work piece quality. The three-dimensional model of eccentric shaft grinder is drawn by Pro/E three-dimensional drawing software, the model is imported into ANSYS Workbench Finite element analysis software, and the finite element analysis is carried out, and then the variation and parameters of each component of the bed are obtained by the modal analysis result. The natural frequencies and formations of the first six steps of the eccentric shaft grinder are obtained by modal analysis, and the weak links of the parts of the grinder are found out, and a reference improvement method is proposed for the design of the eccentric shaft grinder in the future.

Assessment of behavior factor of eccentrically braced frame with ...

African Journals Online (AJOL)

Assessment of behavior factor of eccentrically braced frame with vertical link in cyclic loading. ... Journal of Fundamental and Applied Sciences ... In order to understand the behavior of these structures using non-linear static and dynamic analysis of building's behavior factor, eccentric and exocentric systems were calculated ...

Different training responses to eccentric endurance exercise at low and moderate altitudes in pre-diabetic men: a pilot study.

Science.gov (United States)

Klarod, Kultida; Philippe, Marc; Gatterer, Hannes; Burtscher, Martin

2017-01-01

This pilot study aimed (a) to evaluate the effects of eccentric exercise training at low and moderate altitudes on physical fitness in pre-diabetic men and (b) to establish whether or not oxidative stress levels and antioxidant status were associated with performance improvements. In this crossover trial, five pre-diabetic men conducted nine downhill walking sessions (3 days/week, 3 consecutive weeks) at low altitude (from 1360 to 850 m) and one year later at moderate altitude (from 2447 to 2000 m). Exercise testing and the determination of parameters of oxidative stress and antioxidant capacity were performed pre- and post-training. The biological antioxidant activity of plasma (BAP) increased after eccentric training at moderate altitude ( p  training at moderate-altitude training ( p  = 0.009). Maximum power output improved after training at low altitude and the changes were significantly related to baseline BAP/dROMs ratio ( r  = 0.90). No decrease was seen for fasting plasma glucose. Eccentric exercise training in pre-diabetic men improved performance only when performed at low altitude and this improvement was positively related to the baseline BAP/dROMs ratio. In contrast, 3 weeks of eccentric exercise training increased BAP levels and the BAP/dROMs ratio only at moderate altitude without improving the performance. Thus, one might speculate that the BAP/dROMs ratio has to increase before performance improvements occur at moderate altitude.

Frequency modulation reveals the phasing of orbital eccentricity during Cretaceous Oceanic Anoxic Event II and the Eocene hyperthermals

Czech Academy of Sciences Publication Activity Database

Laurin, Jiří; Meyers, S. R.; Galeotti, S.; Lanci, L.

2016-01-01

Roč. 442, 15 May (2016), s. 143-156 ISSN 0012-821X R&D Projects: GA MŠk LH12041 Institutional support: RVO:67985530 Keywords : orbital eccentricity * cyclostratigraphy * Cenomanian Subject RIV: DB - Geology ; Mineralogy Impact factor: 4.409, year: 2016

The Effect of Body Mass on Eccentric Knee-Flexor Strength Assessed With an Instrumented Nordic Hamstring Device (Nordbord) in Football Players.

Science.gov (United States)

Buchheit, Martin; Cholley, Yannick; Nagel, Mark; Poulos, Nicholas

2016-09-01

To examine the effect of body mass (BM) on eccentric knee-flexor strength using the Nordbord and offer simple guidelines to control for the effect of BM on knee-flexor strength. Data from 81 soccer players (U17, U19, U21, senior 4th French division, and professionals) and 41 Australian Football League (AFL) players were used for analysis. They all performed 1 set of 3 maximal repetitions of the bilateral Nordic hamstring exercise, with the greatest strength measure used for analysis. The main regression equation obtained from the overall sample was used to predict eccentric knee-flexor strength from a given BM (moderate TEE, 22%). Individual deviations from the BM-predicted score were used as a BM-free index of eccentric knee- flexor strength. There was a large (r = .55, 90% confidence limits .42;.64) correlation between eccentric knee-flexor strength and BM. Heavier and older players (professionals, 4th French division, and AFL) outperformed their lighter and younger (U17-U21) counterparts, with the soccer professionals presenting the highest absolute strength. Professional soccer players were the only ones to show strength values likely slightly greater than those expected for their BM. Eccentric knee-flexor strength, as assessed with the Nordbord, is largely BM-dependent. To control for this effect, practitioners may compare actual test performances with the expected strength for a given BM, using the following predictive equation: Eccentric strength (N) = 4 × BM (kg) + 26.1. Professional soccer players with specific knee-flexor-training history and enhanced neuromuscular performance may show higher than expected values.

Estimating Neural Control from Concentric vs. Eccentric Surface Electromyographic Representations during Fatiguing, Cyclic Submaximal Back Extension Exercises

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Gerold R. Ebenbichler

2017-05-01

Full Text Available Purpose: To investigate the differences in neural control of back muscles activated during the eccentric vs. the concentric portions of a cyclic, submaximal, fatiguing trunk extension exercise via the analysis of amplitude and time-frequency parameters derived from surface electromyographic (SEMG data.Methods: Using back dynamometers, 87 healthy volunteers performed three maximum voluntary isometric trunk extensions (MVC's, an isometric trunk extension at 80% MVC, and 25 cyclic, dynamic trunk extensions at 50% MVC. Dynamic testing was performed with the trunk angular displacement ranging from 0° to 40° and the trunk angular velocity set at 20°/s. SEMG data was recorded bilaterally from the iliocostalis lumborum at L1, the longissimus dorsi at L2, and the multifidus muscles at L5. The initial value and slope of the root mean square (RMS-SEMG and the instantaneous median frequency (IMDF-SEMG estimates derived from the SEMG recorded during each exercise cycle were used to investigate the differences in MU control marking the eccentric vs. the concentric portions of the exercise.Results: During the concentric portions of the exercise, the initial RMS-SEMG values were almost twice those observed during the eccentric portions of the exercise. The RMS-SEMG values generally increased during the concentric portions of the exercise while they mostly remained unchanged during the eccentric portions of the exercise with significant differences between contraction types. Neither the initial IMDF-SEMG values nor the time-course of the IMDF-SEMG values significantly differed between the eccentric and the concentric portions of the exercise.Conclusions: The comparison of the investigated SEMG parameters revealed distinct neural control strategies during the eccentric vs. the concentric portions of the cyclic exercise. We explain these differences by relying upon the principles of orderly recruitment and common drive governing motor unit behavior.

Comparisons of eccentric knee flexor strength and asymmetries across elite, sub-elite and school level cricket players

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Wade J. Chalker

2016-02-01

Full Text Available Background. There has been a continual increase in injury rates in cricket, with hamstring strain injuries (HSIs being the most prominent. Eccentric knee flexor weakness and bilateral asymmetries are major modifiable risk factors for future HSIs. However, there is a lack of data relating to eccentric hamstring strength in cricket at any skill level. The objective of this study was to compare eccentric knee flexor strength and bilateral asymmetries in elite, sub-elite and school level cricket players; and to determine if playing position and limb role influenced these eccentric knee flexor strength indices. Methods. Seventy four male cricket players of three distinct skill levels performed three repetitions of the Nordic hamstring exercise on the experimental device. Strength was assessed as the absolute and relative mean peak force output for both limbs, with bilateral asymmetries. Differences in mean peak force outputs between skill level and playing positions were measured. Results. There were no significant differences between elite, sub-elite and school level athletes for mean peak force and bilateral asymmetries of the knee flexors. There were no significant differences observed between bowler’s and batter’s mean peak force and bilateral asymmetries. There were no significant differences between front and back limb mean peak force outputs. Discussion. Skill level, playing position and limb role appeared to have no significant effect on eccentric knee flexor strength and bilateral asymmetries. Future research should seek to determine whether eccentric knee flexor strength thresholds are predictive of HSIs in cricket and if specific eccentric knee flexor strengthening can reduce these injuries.

Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis.

Science.gov (United States)

Langberg, H; Ellingsgaard, H; Madsen, T; Jansson, J; Magnusson, S P; Aagaard, P; Kjaer, M

2007-02-01

It has been shown that 12 weeks of eccentric heavy resistance training can reduce pain in runners suffering from chronic Achilles tendinosis, but the mechanism behind the effectiveness of this treatment is unknown. The present study investigates the local effect of an eccentric training regime on elite soccer players suffering from chronic Achilles tendinosis on the turnover of the peritendinous connective tissue. Twelve elite male soccer players, of whom six suffered from unilateral tendinosis and six were healthy controls, participated in this study. All participants performed 12 weeks of heavy-resistance eccentric training apart from their regular training and soccer activity. Before and after the training period the tissue concentration of indicators of collagen turnover was measured by the use of the microdialysis technique. After training, collagen synthesis was increased in the initially injured tendon (n=6; carboxyterminal propeptide of type I collagen (PICP): pre 3.9+/-2.5 microg/L to post 19.7+/-5.4 microg/L, Ptendons in response to training (n=6; PICP: pre 8.3+/-5.2 microg/L to post 11.5+/-5.0 microg/L, P>0.05). Collagen degradation, measured as carboxyterminal telopeptide region of type I collagen (ICTP), was not affected by training neither in the injured nor in the healthy tendons. The clinical effect of the 12 weeks of eccentric training was determined by using a standardized loading procedure of the Achilles tendons showing a decrease in pain in all the chronic injured tendons (VAS before 44+/-9, after 13+/-9; Peccentric training regime. The present study demonstrates that chronically injured Achilles tendons respond to 12 weeks of eccentric training by increasing collagen synthesis rate. In contrast, the collagen metabolism in healthy control tendons seems not to be affected by eccentric training. These findings could indicate a relation between collagen metabolism and recovery from injury in human tendons.

Hereditary effects in eccentric compact binary inspirals to third post-Newtonian order

Science.gov (United States)

Loutrel, Nicholas; Yunes, Nicolás

2017-02-01

While there has been much success in understanding the orbital dynamics and gravitational wave emission of eccentric compact binaries in the post-Newtonian formalism, some problems still remain. The largest of these concerns hereditary effects: non-linear phenomena related to the scattering off of the background curved spacetime (tails) and to the generation of gravitational waves by gravitational waves (memory). Currently, these hereditary effects are only known numerically for arbitrary eccentricity through infinite sums of Bessel functions, with closed-form, analytic results only available in the small eccentricity limit. We here calculate, for the first time, closed-form, analytic expressions for all hereditary effects to third post-Newtonian order in binaries with arbitrary eccentricity. For the tails, we first asymptotically expand all Bessel functions in high eccentricity and find a superasymptotic series for each enhancement factor, accurate to better than 10-3 relative to post-Newtonian numerical calculations at all eccentricities. We further improve the small-eccentricity behavior of the superasymptotic series by generating hyperasymptotic expressions for each enhancement factor, typically accurate to better than 10-8 at all eccentricities. For the memory, we discuss its computation within the context of an osculating approximation of the binary’s orbit and the difficulties that arise. Our closed-form analytic expressions for the hereditary fluxes allow us to numerically compute orbital phases that are identical to those found using an infinite sum of Bessel functions to double numerical precision.

Hereditary effects in eccentric compact binary inspirals to third post-Newtonian order

International Nuclear Information System (INIS)

Loutrel, Nicholas; Yunes, Nicolás

2017-01-01

While there has been much success in understanding the orbital dynamics and gravitational wave emission of eccentric compact binaries in the post-Newtonian formalism, some problems still remain. The largest of these concerns hereditary effects: non-linear phenomena related to the scattering off of the background curved spacetime (tails) and to the generation of gravitational waves by gravitational waves (memory). Currently, these hereditary effects are only known numerically for arbitrary eccentricity through infinite sums of Bessel functions, with closed-form, analytic results only available in the small eccentricity limit. We here calculate, for the first time, closed-form, analytic expressions for all hereditary effects to third post-Newtonian order in binaries with arbitrary eccentricity. For the tails, we first asymptotically expand all Bessel functions in high eccentricity and find a superasymptotic series for each enhancement factor, accurate to better than 10 −3 relative to post-Newtonian numerical calculations at all eccentricities. We further improve the small-eccentricity behavior of the superasymptotic series by generating hyperasymptotic expressions for each enhancement factor, typically accurate to better than 10 −8 at all eccentricities. For the memory, we discuss its computation within the context of an osculating approximation of the binary’s orbit and the difficulties that arise. Our closed-form analytic expressions for the hereditary fluxes allow us to numerically compute orbital phases that are identical to those found using an infinite sum of Bessel functions to double numerical precision. (paper)

Effects of Short-Term Docosahexaenoic Acid Supplementation on Markers of Inflammation after Eccentric Strength Exercise in Women

Directory of Open Access Journals (Sweden)

Katherine E. Corder, Katherine R. Newsham, Jennifer L. McDaniel, Uthayashanker R. Ezekiel, Edward P. Weiss

2016-03-01

Full Text Available The omega-3 fatty acid docosahexaenoic acid (DHA has anti-inflammatory and anti-nociceptive (pain inhibiting effects. Because strenuous exercise often results in local inflammation and pain, we hypothesized that DHA supplementation attenuates the rise in markers of local muscle inflammation and delayed onset muscle soreness (DOMS that occur after eccentric strength exercise. Twenty-seven, healthy women (33 ± 2 y, BMI 23.1±1.0 kg·m-2 were randomized to receive 9d of 3000 mg/d DHA or placebo in a double-blind fashion. On day 7 of the supplementation period, the participants performed 4 sets of maximal-effort eccentric biceps curl exercise. Before and 48h after the eccentric exercise, markers of inflammation were measured including measures of muscle soreness (10-point visual analog pain scale, VAS, swelling (arm circumference, muscle stiffness (active and passive elbow extension, skin temperature, and salivary C-reactive protein (CRP concentrations. As expected, muscle soreness and arm circumference increased while active and passive elbow extension decreased. The increase in soreness was 23% less in the DHA group (48h increase in VAS soreness ratings: 4.380.4 vs. 5.600.5, p=0.02. Furthermore, the number of subjects who were able to achieve full active elbow extension 48h after eccentric exercise was greater in the DHA group (71% vs. 15%, p = 0.006, indicating significantly less muscle stiffness. No between-group differences were observed for passive elbow extension (p = 0.78 or arm swelling (p = 0.75. Skin temperature and salivary CRP concentrations did not change from baseline to 48h after exercise in either group. These findings indicate that short-term DHA supplementation reduces exercise-induced muscle soreness and stiffness. Therefore, in addition to other health benefits that n-3 fatty acids have been associated with, DHA supplementation could be beneficial for improving tolerance to new and/or strenuous exercise programs and thereby

Searching for gravitational-wave signals emitted by eccentric compact binaries using a non-eccentric template bank: implications for ground-based detectors

Energy Technology Data Exchange (ETDEWEB)

Cokelaer, T; Pathak, D, E-mail: Thomas.Cokelaer@astro.cf.ac.u, E-mail: Devanka.Pathak@astro.cf.ac.u [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom)

2009-02-21

Most of the inspiralling compact binaries are expected to be circularized by the time their gravitational-wave signals enter the frequency band of ground-based detectors such as LIGO or VIRGO. However, it is not excluded that some of these binaries might still possess a significant eccentricity at a few tens of hertz. Despite this possibility, current search pipelines-based on matched filtering techniques-consider only non-eccentric templates. The effect of such an approximation on the loss of signal-to-noise ratio (SNR) has been investigated by Martel and Poisson (1999 Phys. Rev. D 60 124008) in the context of initial LIGO detector. They ascertained that non-eccentric templates will be successful at detecting eccentric signals. We revisit their work by incorporating current and future ground-based detectors and precisely quantify the exact loss of SNR. In order to be more faithful to an actual search, we maximized the SNR over a template bank, whose minimal match is set to 95%. For initial LIGO detector, we claim that the initial eccentricity does not need to be taken into account in our searches for any system with total mass M element of [2-45]M{sub o-dot} if e{sub 0} approx< 0.05 because the loss of SNR (about 5%) is consistent with the discreteness of the template bank. Similarly, this statement is also true for systems with M element of [6-35]M{sub o-dot} and e{sub 0} approx< 0.10. However, by neglecting the eccentricity in our searches, significant loss of detection (larger than 10%) may arise as soon as e{sub 0} >= 0.05 for neutron-star binaries. We also provide exhaustive results for VIRGO, Advanced LIGO and Einstein Telescope detectors. It is worth noting that for Einstein Telescope, neutron star binaries with e{sub 0} >= 0.02 lead to a 10% loss of detection.

Skeletal muscle collagen content in humans after high-force eccentric contractions

DEFF Research Database (Denmark)

Mackey, Abigail; Donnelly, Alan E; Turpeenniemi-Hujanen, Taina

2004-01-01

The purpose of this study was to investigate the effects of high-force eccentric muscle contractions on collagen remodeling and on circulating levels of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in humans. Nine volunteers [5 men and 4 women, mean age 23 (SD...... 4) yr] each performed a bout of 100 maximum voluntary eccentric contractions of the knee extensors. Muscle biopsies were taken before exercise and on days 4 and 22 afterward. Image analysis of stained tissue sections was used to quantify endomysial collagen staining intensity. Maximum voluntary...... contractile force declined by 39 +/- 23% (mean +/- SD) on day 2 postexercise and recovered thereafter. Serum creatine kinase activity peaked on day 4 postexercise (P Collagen type IV staining intensity increased significantly on day 22 postexercise to 126 +/- 29% (mean +/- SD) of preexercise values...

The Behaviour of Palm Oil Fibre Block Masonry Prism under Eccentric Compressive Loading

Science.gov (United States)

Mokhtar, Mardiha; Kolop, Roslan; Baizura Hamid, Nor; Kaamin, Masiri; Farhan Rosdi, Mohd; Ngadiman, Norhayati; Sahat, Suhaila

2017-08-01

Dry-stacked masonry offers great benefits in constructing masonry buildings. Several examples from previous research show that dry masonry is reasonable alternative to the traditional building system. By addition of fibre, the ductility and the propagation of cracking will be improved. This study investigates the dry stack oil palm fibre block prisms which were subjected to eccentricity compression loads. These concrete blocks were cast using a single mould with suitable fibre-cement composition namely 1:4 (cement: sand) and 0.40 water to the cement ratio based on cement weight. Prisms test using 400 (length) × 150 (width) × 510 (height) mm specimen was carried under eccentric load. There were forty eight (48) prisms built with different configurations based on their volume of fibre. In this study, one types of grout were used namely the fine grout of mix 1:3:2 (cement: sand: aggregate (5mm maximum). Based on the test performed, the failure mechanism and influencing parameters were discussed. From compressive strength test result, it shows that the strength of concrete block decreased with the increase of fibre used. Although the control sample has the higher strength compared to concrete with EFB, it can be seen from mode failure of masonry prism that fibre could extend the cracking time. These results show that the oil palm fibre blocks can improve the failure behaviour and suitable to be used as load bearing wall construction in Malaysia.

Stability analysis of shallow tunnels subjected to eccentric loads by a boundary element method

Directory of Open Access Journals (Sweden)

Mehdi Panji

2016-08-01

Full Text Available In this paper, stress behavior of shallow tunnels under simultaneous non-uniform surface traction and symmetric gravity loading was studied using a direct boundary element method (BEM. The existing full-plane elastostatic fundamental solutions to displacement and stress fields were used and implemented in a developed algorithm. The cross-section of the tunnel was considered in circular, square, and horseshoe shapes and the lateral coefficient of the domain was assumed as unit quantity. Double-node procedure of the BEM was applied at the corners to improve the model including sudden traction changes. The results showed that the method used was a powerful tool for modeling underground openings under various external as well as internal loads. Eccentric loads significantly influenced the stress pattern of the surrounding tunnel. The achievements can be practically used in completing and modifying regulations for stability investigation of shallow tunnels.

Loners, Groupies, and Long-term Eccentricity (and Inclination) Behavior: Insights from Secular Theory

Science.gov (United States)

Van Laerhoven, Christa L.

2015-05-01

Considering the secular dynamics of multi-planet systems provides substantial insight into the interactions between planets in those systems. Secular interactions are those that don't involve knowing where a planet is along its orbit, and they dominate when planets are not involved in mean motion resonances. These interactions exchange angular momentum among the planets, evolving their eccentricities and inclinations. To second order in the planets' eccentricities and inclinations, the eccentricity and inclination perturbations are decoupled. Given the right variable choice, the relevant differential equations are linear and thus the eccentricity and inclination behaviors can be described as a sum of eigenmodes. Since the underlying structure of the secular eigenmodes can be calculated using only the planets' masses and semi-major axes, one can elucidate the eccentricity and inclination behavior of planets in exoplanet systems even without knowing the planets' current eccentricities and inclinations. I have calculated both the eccentricity and inclination secular eigenmodes for the population of known multi-planet systems whose planets have well determined masses and periods. Using this catalog of secular character, I will discuss the prevalence of dynamically grouped planets ('groupies') versus dynamically uncoupled planets ('loners') and how this relates to the exoplanets' long-term eccentricity and inclination behavior. I will also touch on the distribution of the secular eigenfreqiencies.

How to Make Eccentricity Cycles in Stratigraphy: the Role of Compaction

Science.gov (United States)

Liu, W.; Hinnov, L.; Wu, H.; Pas, D.

2017-12-01

Milankovitch cycles from astronomically driven climate variations have been demonstrated as preserved in cyclostratigraphy throughout geologic time. These stratigraphic cycles have been identified in many types of proxies, e.g., gamma ray, magnetic susceptibility, oxygen isotopes, carbonate content, grayscale, etc. However, the commonly prominent spectral power of orbital eccentricity cycles in stratigraphy is paradoxical to insolation, which is dominated by precession index power. How is the spectral power transferred from precession to eccentricity in stratigraphy? Nonlinear sedimentation and bioturbation have long been identified as players in this transference. Here, we propose that in the absence of bioturbation differential compaction can generate the transference. Using insolation time series, we trace the steps by which insolation is transformed into stratigraphy, and how differential compaction of lithology acts to transfer spectral power from precession to eccentricity. Differential compaction is applied to unique values of insolation, which is assumed to control the type of deposited sediment. High compaction is applied to muds, and progressively lower compaction is applied to silts and sands, or carbonate. Linear differential compaction promotes eccentricity spectral power, but nonlinear differential compaction elevates eccentricity spectral power to dominance and precession spectral power to near collapse as is often observed in real stratigraphy. Keywords: differential compaction, cyclostratigraphy, insolation, eccentricity

Influence of borehole-eccentred tools on wireline and logging-while-drilling sonic logging measurements

KAUST Repository

Pardo, David

2013-02-13

We describe a numerical study to quantify the influence of tool-eccentricity on wireline (WL) and logging-while-drilling (LWD) sonic logging measurements. Simulations are performed with a height-polynomial-adaptive (hp) Fourier finite-element method that delivers highly accurate solutions of linear visco-elasto-acoustic problems in the frequency domain. The analysis focuses on WL instruments equipped with monopole or dipole sources and LWD instruments with monopole excitation. Analysis of the main propagation modes obtained from frequency dispersion curves indicates that the additional high-order modes arising as a result of borehole-eccentricity interfere with the main modes (i.e., Stoneley, pseudo-Rayleigh and flexural). This often modifies (decreases) the estimation of shear and compressional formation velocities, which should be corrected (increased) to account for borehole-eccentricity effects. Undesired interferences between different modes can occur at different frequencies depending upon the properties of the formation and fluid annulus size, which may difficult the estimation of the formation velocities. © 2013 European Association of Geoscientists & Engineers.

The Eccentric-distance Sum of Some Graphs

OpenAIRE

P, Padmapriya; Mathad, Veena

2017-01-01

Let $G = (V,E)$ be a simple connected graph. Theeccentric-distance sum of $G$ is defined as$\\xi^{ds}(G) =\\ds\\sum_{\\{u,v\\}\\subseteq V(G)} [e(u)+e(v)] d(u,v)$, where $e(u)$ %\\dsis the eccentricity of the vertex $u$ in $G$ and $d(u,v)$ is thedistance between $u$ and $v$. In this paper, we establish formulaeto calculate the eccentric-distance sum for some graphs, namelywheel, star, broom, lollipop, double star, friendship, multi-stargraph and the join of $P_{n-2}$ and $P_2$.

The eccentric-distance sum of some graphs

Directory of Open Access Journals (Sweden)

Padmapriya P

2017-04-01

Full Text Available Let $G = (V,E$ be a simple connected graph. Theeccentric-distance sum of $G$ is defined as$\\xi^{ds}(G =\\ds\\sum_{\\{u,v\\}\\subseteq V(G} [e(u+e(v] d(u,v$, where $e(u$ %\\dsis the eccentricity of the vertex $u$ in $G$ and $d(u,v$ is thedistance between $u$ and $v$. In this paper, we establish formulaeto calculate the eccentric-distance sum for some graphs, namelywheel, star, broom, lollipop, double star, friendship, multi-stargraph and the join of $P_{n-2}$ and $P_2$.

Astym treatment vs. eccentric exercise for lateral elbow tendinopathy: a randomized controlled clinical trial

Science.gov (United States)

Stegink-Jansen, Caroline W.

2015-01-01

Introduction. Patients with chronic lateral elbow (LE) tendinopathy, commonly known as tennis elbow, often experience prolonged symptoms and frequent relapses. Astym treatment, evidenced in animal studies to promote the healing and regeneration of soft tissues, is hypothesized to improve outcomes in LE tendinopathy patients. This study had two objectives: (1) to compare the efficacy of Astym treatment to an evidence-based eccentric exercise program (EE) for patients with chronic LE tendinopathy, and (2) to quantify outcomes of subjects non-responsive to EE who were subsequently treated with Astym treatment. Study Design. Prospective, two group, parallel, randomized controlled trial completed at a large orthopedic center in Indiana. Inclusion criteria: age range of 18–65 years old, with clinical indications of LE tendinopathy greater than 12 weeks, with no recent corticosteriod injection or disease altering comorbidities. Methods. Subjects with chronic LE tendinopathy (107 subjects with 113 affected elbows) were randomly assigned using computer-generated random number tables to 4 weeks of Astym treatment (57 elbows) or EE treatment (56 elbows). Data collected at baseline, 4, 8, 12 weeks, 6 and 12 months. Primary outcome measure: DASH; secondary outcome measures: pain with activity, maximum grip strength and function. The treating physicians and the rater were blinded; subjects and treating clinicians could not be blinded due to the nature of the treatments. Results. Resolution response rates were 78.3% for the Astym group and 40.9% for the EE group. Astym subjects showed greater gains in DASH scores (p = 0.047) and in maximum grip strength (p = 0.008) than EE subjects. Astym therapy also resolved 20/21 (95.7%) of the EE non-responders, who showed improvements in DASH scores (p effects were reported. Conclusion. This study suggests Astym therapy is an effective treatment option for patients with LE tendinopathy, as an initial treatment, and after an eccentric

Gravitational waves from spinning eccentric binaries

Science.gov (United States)

Csizmadia, Péter; Debreczeni, Gergely; Rácz, István; Vasúth, Mátyás

2012-12-01

This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations, while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems, it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity, thus confirming a similar result obtained by Brown and Zimmerman (2010 Phys. Rev. D 81 024007). In addition, by investigating the validity of the energy balance relation we show that, contrary to the general expectations, the PN approximation should not be applied once the PN parameter gets beyond the critical value ˜0.08 - 0.1. Finally, by studying the early phase of the gravitational waves emitted by strongly eccentric binary systems—which could be formed e.g. in various many-body interactions in the galactic halo—we have found that they possess very specific characteristics which may be used to identify these type of binary systems. This paper is dedicated to the memory of our colleague and friend Péter Csizmadia a young physicist, computer expert and one of the best Hungarian mountaineers who disappeared in China’s Sichuan near the Ren Zhong Feng peak of the Himalayas on 23 Oct. 2009. We started to develop CBwaves jointly with Péter a couple of months before he left for China.

Physiological and Neural Adaptations to Eccentric Exercise: Mechanisms and Considerations for Training

Directory of Open Access Journals (Sweden)

Nosratollah Hedayatpour

2015-01-01

Full Text Available Eccentric exercise is characterized by initial unfavorable effects such as subcellular muscle damage, pain, reduced fiber excitability, and initial muscle weakness. However, stretch combined with overload, as in eccentric contractions, is an effective stimulus for inducing physiological and neural adaptations to training. Eccentric exercise-induced adaptations include muscle hypertrophy, increased cortical activity, and changes in motor unit behavior, all of which contribute to improved muscle function. In this brief review, neuromuscular adaptations to different forms of exercise are reviewed, the positive training effects of eccentric exercise are presented, and the implications for training are considered.

Non-linear hydrodynamic instability and turbulence in eccentric astrophysical discs with vertical structure

Science.gov (United States)

Wienkers, A. F.; Ogilvie, G. I.

2018-04-01

Non-linear evolution of the parametric instability of inertial waves inherent to eccentric discs is studied by way of a new local numerical model. Mode coupling of tidal deformation with the disc eccentricity is known to produce exponentially growing eccentricities at certain mean-motion resonances. However, the details of an efficient saturation mechanism balancing this growth still are not fully understood. This paper develops a local numerical model for an eccentric quasi-axisymmetric shearing box which generalises the often-used cartesian shearing box model. The numerical method is an overall second order well-balanced finite volume method which maintains the stratified and oscillatory steady-state solution by construction. This implementation is employed to study the non-linear outcome of the parametric instability in eccentric discs with vertical structure. Stratification is found to constrain the perturbation energy near the mid-plane and localise the effective region of inertial wave breaking that sources turbulence. A saturated marginally sonic turbulent state results from the non-linear breaking of inertial waves and is subsequently unstable to large-scale axisymmetric zonal flow structures. This resulting limit-cycle behaviour reduces access to the eccentric energy source and prevents substantial transport of angular momentum radially through the disc. Still, the saturation of this parametric instability of inertial waves is shown to damp eccentricity on a time-scale of a thousand orbital periods. It may thus be a promising mechanism for intermittently regaining balance with the exponential growth of eccentricity from the eccentric Lindblad resonances and may also help explain the occurrence of "bursty" dynamics such as the superhump phenomenon.

Eccentric Contraction-Induced Muscle Fibre Adaptation

Directory of Open Access Journals (Sweden)

Arabadzhiev T. I.

2009-12-01

Full Text Available Hard-strength training induces strength increasing and muscle damage, especially after eccentric contractions. Eccentric contractions also lead to muscle adaptation. Symptoms of damage after repeated bout of the same or similar eccentrically biased exercises are markedly reduced. The mechanism of this repeated bout effect is unknown. Since electromyographic (EMG power spectra scale to lower frequencies, the adaptation is related to neural adaptation of the central nervous system (CNS presuming activation of slow-non-fatigable motor units or synchronization of motor unit firing. However, the repeated bout effect is also observed under repeated stimulation, i.e. without participation of the CNS. The aim of this study was to compare the possible effects of changes in intracellular action potential shape and in synchronization of motor units firing on EMG power spectra. To estimate possible degree of the effects of central and peripheral changes, interferent EMG was simulated under different intracellular action potential shapes and different degrees of synchronization of motor unit firing. It was shown that the effect of changes in intracellular action potential shape and muscle fibre propagation velocity (i.e. peripheral factors on spectral characteristics of EMG signals could be stronger than the effect of synchronization of firing of different motor units (i.e. central factors.

Densities and eccentricities of 139 Kepler planets from transit time variations

Energy Technology Data Exchange (ETDEWEB)

Hadden, Sam; Lithwick, Yoram [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)

2014-05-20

We extract densities and eccentricities of 139 sub-Jovian planets by analyzing transit time variations (TTVs) obtained by the Kepler mission through Quarter 12. We partially circumvent the degeneracies that plague TTV inversion with the help of an analytical formula for the TTV. From the observed TTV phases, we find that most of these planets have eccentricities of the order of a few percent. More precisely, the rms eccentricity is 0.018{sub −0.004}{sup +0.005}, and planets smaller than 2.5 R {sub ⊕} are around twice as eccentric as those bigger than 2.5 R {sub ⊕}. We also find a best-fit density-radius relationship ρ ≈ 3 g cm{sup –3} × (R/3 R {sub ⊕}){sup –2.3} for the 56 planets that likely have small eccentricity and hence small statistical correction to their masses. Many planets larger than 2.5 R {sub ⊕} are less dense than water, implying that their radii are largely set by a massive hydrogen atmosphere.

Stress intensity factors of eccentric cracks in bi-materials plate under mode I loading

Energy Technology Data Exchange (ETDEWEB)

Ismail, A. E. [Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Batu Pahat, Johor (Malaysia)

2015-05-15

Bi-material plates were generally used to joint electronic devices or mechanical components requiring dissimilar materials to be attached. During services, mechanical failure can be occurred due to the formation of cracks at the interfacial joint or away from the centre. Generally, linear elastic fracture mechanics approach is used to characterize these cracks based on stress intensity factors (SIF). Based on the literature survey, the SIFs for the central cracks were easily available. However, the SIFs for eccentric cracks were difficult to obtain. Therefore, this paper presented the SIFs for eccentric cracks subjected to mode I tension loading. Three important parameters were used such as relative crack depth, a/L, relative offset distance, b/L and elastic mismatch, E{sub 1}/E{sub 2} or α. It was found that such parameters significantly affected the characteristic of SIFs and it was depend on the location of cracks.

Influence of borehole-eccentred tools on wireline and logging-while-drilling sonic logging measurements

KAUST Repository

Pardo, David; Matuszyk, Paweł Jerzy; Torres-Verdí n, Carlos; Mora Cordova, Angel; Muga, Ignacio; Calo, Victor M.

2013-01-01

We describe a numerical study to quantify the influence of tool-eccentricity on wireline (WL) and logging-while-drilling (LWD) sonic logging measurements. Simulations are performed with a height-polynomial-adaptive (hp) Fourier finite-element method

Eccentric bracing of steel frames in seismic design

International Nuclear Information System (INIS)

Popov, E.P.; Manheim, D.

1981-01-01

The general concepts of designing eccentrically braced steel frames are discussed. A number of possible bracing configurations are pointed out which are suitable for this type of framing. The necessity for considering the collapse mechanism for the selected frame is brought out, and the need for considering the ductility demands for the critical elements is indicated. The need for web stiffness along the critical beam elements (links), and the necessity for lateral bracing at the potential plastic hinges is emphasized. Properly designed eccentrically braced frames provide good drift control for moderate earthquakes, and good ductility for extreme earthquakes. Experience gained in practice attests to the practicality and economy of this kind of framing. The major disadvantage of properly designed eccentrically braced frames lies in the fact that high local distortions may occur during a severe earthquake requiring repair. However, such severe distortions should attenuate rapidly from the damaged areas. (orig./HP)

Effects of 12-wk eccentric calf muscle training on muscle-tendon glucose uptake and SEMG in patients with chronic Achilles tendon pain.

Science.gov (United States)

Masood, Tahir; Kalliokoski, Kari; Magnusson, S Peter; Bojsen-Møller, Jens; Finni, Taija

2014-07-15

High-load eccentric exercises have been a key component in the conservative management of chronic Achilles tendinopathy. This study investigated the effects of a 12-wk progressive, home-based eccentric rehabilitation program on ankle plantar flexors' glucose uptake (GU) and myoelectric activity and Achilles tendon GU. A longitudinal study design with control (n = 10) and patient (n = 10) groups was used. Surface electromyography (SEMG) from four ankle plantar flexors and GU from the same muscles and the Achilles tendon were measured during submaximal intermittent isometric plantar flexion task. The results indicated that the symptomatic leg was weaker (P eccentric rehabilitation. Additionally, the rehabilitation resulted in greater GU in both soleus (P tendon GU than the controls (P effect on the tendon GU. Concerning SEMG, at baseline, soleus showed more relative activity in the symptomatic leg compared with both the asymptomatic and control legs (P Eccentric rehabilitation was effective in decreasing subjective severity of Achilles tendinopathy. It also resulted in redistribution of relative electrical activity, but not metabolic activity, within the triceps surae muscle. Copyright © 2014 the American Physiological Society.

The effect of wheel eccentricity and run-out on grinding forces, waviness, wheel wear and chatter

OpenAIRE

O'DONNELL, GARRET; MURPHY, STUART

2011-01-01

PUBLISHED The effect of grinding-wheel eccentricity on grinding forces, wheel wear and final waviness height was studied. Eccentricity was evident in force oscillations and acceleration and audio measurements. A model was developed to predict final scallop-profile shape from grinding parameters and eccentricity. Recommendations are given on detecting eccentricity and determining when eccentricity is tolerable.

Climate of an Earth-Like World with Changing Eccentricity

Science.gov (United States)

Kohler, Susanna

2017-02-01

Having a giant planet like Jupiter next door can really wreak havoc on your orbit! A new study examines what such a bad neighbor might mean for the long-term climate of an Earth-like planet.Influence of a Bad NeighborThe presence of a Jupiter-like giant planet in a nearby orbit can significantly affect how terrestrial planets evolve dynamically, causing elements like the planets orbital eccentricities and axial tilts to change over time. Earth is saved this inconvenience Jupiter isnt close enough to significantly influence us, and our large moon stabilizes our orbit against Jupiters tugs.Top panels: Authors simulationoutcomes for Case1, in which the planets eccentricity varies from 0 to 0.283 over 6500 years. Bottom panels: Outcomes for Case 2, in which the planets eccentricity varies from 0 to 0.066 over 4500 years. The highereccentricities reached in Case 1 causes the climate parameters to vary more widely. Click for a better look! [Way Georgakarakos 2017]Mars, on the other hand, isnt as lucky: its possible that Jupiters gravitational pull causes Marss axial tilt, for instance, to evolve through a range as large as 0 to 60 degrees on timescales of millions of years! Marss orbital eccentricity is similarly thought to vary due to Jupiters influence, and both of these factors play a major role in determining Marss climate.As exoplanet missions discover more planets many of which are Earth-like we must carefully consider which among these are most likely to be capable of sustaining life. If having a nearby neighbor like a Jupiter can tug an Earth-like world into an orbit with varying eccentricity, how does this affect the planets climate? Will the planet remain temperate? Or will it develop a runaway heating or cooling effect as it orbits, rendering it uninhabitable?Oceans and OrbitsTo examine these questions, two scientists have built the first ever 3D global climate model simulations of an Earth-like world using a fully coupled ocean (necessary for understanding

Reduced firing rates of high threshold motor units in response to eccentric overload.

Science.gov (United States)

Balshaw, Tom G; Pahar, Madhu; Chesham, Ross; Macgregor, Lewis J; Hunter, Angus M

2017-01-01

Acute responses of motor units were investigated during submaximal voluntary isometric tasks following eccentric overload (EO) and constant load (CL) knee extension resistance exercise. Ten healthy resistance-trained participants performed four experimental test sessions separated by 5 days over a 20 day period. Two sessions involved constant load and the other two used eccentric overload. EO and CL used both sessions for different target knee eccentric extension phases; one at 2 sec and the other at 4 sec. Maximal voluntary contractions (MVC) and isometric trapezoid efforts for 10 sec at 70% MVC were completed before and after each intervention and decomposed electromyography was used to measure motor unit firing rate. The firing rate of later recruited, high-threshold motor units declined following the 2-sec EO but was maintained following 2sec CL (P motor units were maintained for both loading types following 4-sec extension phases. MVC and rate of force development where maintained following both EO and CL and 2 and 4 sec phases. This study demonstrates a slower firing rate of high-threshold motor units following fast eccentric overload while MVC was maintained. This suggests that there was a neuromuscular stimulus without cost to the force-generating capacity of the knee extensors. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Detection of Eccentricity Faults in Five-Phase Ferrite-PM Assisted Synchronous Reluctance Machines

Directory of Open Access Journals (Sweden)

Carlos López-Torres

2017-05-01

Full Text Available Air gap eccentricity faults in five-phase ferrite-assisted synchronous reluctance motors (fPMa-SynRMs tend to distort the magnetic flux in the air gap, which in turn affects the spectral content of both the stator currents and the ZSVC (zero-sequence voltage component. However, there is a lack of research dealing with the topic of fault diagnosis in multi-phase PMa-SynRMs, and in particular, those focused on detecting eccentricity faults. An analysis of the spectral components of the line currents and the ZSVC allows the development of fault diagnosis algorithms to detect eccentricity faults. The effect of the operating conditions is also analyzed, since this paper shows that it has a non-negligible impact on the effectivity and sensitivity of the diagnosis based on an analysis of the stator currents and the ZSVC. To this end, different operating conditions are analyzed. The paper also evaluates the influence of the operating conditions on the harmonic content of the line currents and the ZSVC, and determines the most suitable operating conditions to enhance the sensitivity of the analyzed methods. Finally, fault indicators employed to detect eccentricity faults, which are based on the spectral content of the stator currents and the ZSVC, are derived and their performance is assessed. The approach presented in this work may be useful for developing fault diagnosis strategies based on the acquisition and subsequent analysis and interpretation of the spectral content of the line currents and the ZSVC.

Strength deficits identified with concentric action of the hip extensors and eccentric action of the hamstrings predispose to hamstring injury in elite sprinters.

Science.gov (United States)

Sugiura, Yusaku; Saito, Tomoyuki; Sakuraba, Keishoku; Sakuma, Kazuhiko; Suzuki, Eiichi

2008-08-01

Prospective cohort study. In this prospective cohort study of elite sprinters, muscle strength of the hip extensors, as well as of the knee extensors and flexors, was measured to determine a possible relationship between strength deficits and subsequent hamstring injury within 12 months of testing. The method used for testing muscle strength simulated the specific muscle action during late swing and early contact phases when sprinting. There have been no prospective studies in elite sprinters that examine the concentric and eccentric isokinetic strength of the hip extensors and the quadriceps and hamstring muscles in a manner that reflects their actions in late swing or early contact phases of sprinting. Consequently, the causal relationship between hip and thigh muscle strength and hamstring injury in elite sprinters may not be fully understood. Isokinetic testing was performed on 30 male elite sprinters to assess hip extensors, quadriceps, and hamstring muscle strength. The occurrence of hamstring injury among the subjects was determined during the year following the muscle strength measurements. The strength of the hip extensors, quadriceps, and hamstring muscles, as well as the hamstrings-quadriceps and hip extensors- quadriceps ratios were compared. Hamstring injury occurred in 6 subjects during the 1-year period. Isokinetic testing at a speed of 60 degrees /s revealed weakness of the injured limb with eccentric action of the hamstring muscles and during concentric action of the hip extensors. When performing a side-to-side comparison for the injured sprinters, the hamstring injury always occurred on the weaker side. Differences in the hamstrings-quadriceps and hip extensors-quadriceps strength ratios were also evident between uninjured and injured limbs, and this was attributable to deficits in hamstring strength. Hamstring injury in elite sprinters was associated with weakness during eccentric action of the hamstrings and weakness during concentric action of

Eccentric training as a new approach for rotator cuff tendinopathy: Review and perspectives

Science.gov (United States)

Camargo, Paula R; Alburquerque-Sendín, Francisco; Salvini, Tania F

2014-01-01

Excessive mechanical loading is considered the major cause of rotator cuff tendinopathy. Although tendon problems are very common, they are not always easy to treat. Eccentric training has been proposed as an effective conservative treatment for the Achilles and patellar tendinopathies, but less evidence exists about its effectiveness for the rotator cuff tendinopathy. The mechanotransduction process associated with an adequate dose of mechanical load might explain the beneficial results of applying the eccentric training to the tendons. An adequate load increases healing and an inadequate (over or underuse) load can deteriorate the tendon structure. Different eccentric training protocols have been used in the few studies conducted for people with rotator cuff tendinopathy. Further, the effects of the eccentric training for rotator cuff tendinopathy were only evaluated on pain, function and strength. Future studies should assess the effects of the eccentric training also on shoulder kinematics and muscle activity. Individualization of the exercise prescription, comprehension and motivation of the patients, and the establishment of specific goals, practice and efforts should all be considered when prescribing the eccentric training. In conclusion, eccentric training should be used aiming improvement of the tendon degeneration, but more evidence is necessary to establish the adequate dose-response and to determine long-term follow-up effects. PMID:25405092

Accuracy of Estimating Highly Eccentric Binary Black Hole Parameters with Gravitational-wave Detections

Science.gov (United States)

Gondán, László; Kocsis, Bence; Raffai, Péter; Frei, Zsolt

2018-03-01

Mergers of stellar-mass black holes on highly eccentric orbits are among the targets for ground-based gravitational-wave detectors, including LIGO, VIRGO, and KAGRA. These sources may commonly form through gravitational-wave emission in high-velocity dispersion systems or through the secular Kozai–Lidov mechanism in triple systems. Gravitational waves carry information about the binaries’ orbital parameters and source location. Using the Fisher matrix technique, we determine the measurement accuracy with which the LIGO–VIRGO–KAGRA network could measure the source parameters of eccentric binaries using a matched filtering search of the repeated burst and eccentric inspiral phases of the waveform. We account for general relativistic precession and the evolution of the orbital eccentricity and frequency during the inspiral. We find that the signal-to-noise ratio and the parameter measurement accuracy may be significantly higher for eccentric sources than for circular sources. This increase is sensitive to the initial pericenter distance, the initial eccentricity, and the component masses. For instance, compared to a 30 {M}ȯ –30 {M}ȯ non-spinning circular binary, the chirp mass and sky-localization accuracy can improve by a factor of ∼129 (38) and ∼2 (11) for an initially highly eccentric binary assuming an initial pericenter distance of 20 M tot (10 M tot).

Geometrical theory to predict eccentric photorefraction intensity profiles in the human eye

Science.gov (United States)

Roorda, Austin; Campbell, Melanie C. W.; Bobier, W. R.

1995-08-01

In eccentric photorefraction, light returning from the retina of the eye is photographed by a camera focused on the eye's pupil. We use a geometrical model of eccentric photorefraction to generate intensity profiles across the pupil image. The intensity profiles for three different monochromatic aberration functions induced in a single eye are predicted and show good agreement with the measured eccentric photorefraction intensity profiles. A directional reflection from the retina is incorporated into the calculation. Intensity profiles for symmetric and asymmetric aberrations are generated and measured. The latter profile shows a dependency on the source position and the meridian. The magnitude of the effect of thresholding on measured pattern extents is predicted. Monochromatic aberrations in human eyes will cause deviations in the eccentric photorefraction measurements from traditional crescents caused by defocus and may cause misdiagnoses of ametropia or anisometropia. Our results suggest that measuring refraction along the vertical meridian is preferred for screening studies with the eccentric photorefractor.

Leakage flow-induced vibration of an eccentric tube-in-tube slip joint

International Nuclear Information System (INIS)

Mulcahy, T.M.

1985-08-01

Eccentricity of a specific slip-joint design separating two cantilevered, telescoping tubes did not create any self-excited lateral vibrations that had not been observed previously for a concentric slip joint. In fact, the eccentricity made instabilities less likely to occur, but only marginally. Most important, design rules previously established to avoid instabilities for the concentric slip joint remain valid for the eccentric slip joint. 6 refs., 9 figs., 2 tabs

Subjective performance evaluations and employee careers

DEFF Research Database (Denmark)

Frederiksen, Anders; Lange, Fabian; Kriechell, Ben

Firms commonly use supervisor evaluations to assess the performance of employees who work in complex environments. Doubts persist whether their subjective nature invalidates using these performance measures to learn about careers of individuals and to inform theory in personnel economics. We...... examine personnel data from six large companies and establish how subjective ratings, interpreted as ordinal rankings of employee performances within narrowly defined peer-groups, correlate with objective career outcomes. We find many similarities across firms in how subjective ratings correlate with base...

Astym treatment vs. eccentric exercise for lateral elbow tendinopathy: a randomized controlled clinical trial

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Thomas L. Sevier

2015-05-01

Full Text Available Introduction. Patients with chronic lateral elbow (LE tendinopathy, commonly known as tennis elbow, often experience prolonged symptoms and frequent relapses. Astym treatment, evidenced in animal studies to promote the healing and regeneration of soft tissues, is hypothesized to improve outcomes in LE tendinopathy patients. This study had two objectives: (1 to compare the efficacy of Astym treatment to an evidence-based eccentric exercise program (EE for patients with chronic LE tendinopathy, and (2 to quantify outcomes of subjects non-responsive to EE who were subsequently treated with Astym treatment.Study Design. Prospective, two group, parallel, randomized controlled trial completed at a large orthopedic center in Indiana. Inclusion criteria: age range of 18–65 years old, with clinical indications of LE tendinopathy greater than 12 weeks, with no recent corticosteriod injection or disease altering comorbidities.Methods. Subjects with chronic LE tendinopathy (107 subjects with 113 affected elbows were randomly assigned using computer-generated random number tables to 4 weeks of Astym treatment (57 elbows or EE treatment (56 elbows. Data collected at baseline, 4, 8, 12 weeks, 6 and 12 months. Primary outcome measure: DASH; secondary outcome measures: pain with activity, maximum grip strength and function. The treating physicians and the rater were blinded; subjects and treating clinicians could not be blinded due to the nature of the treatments.Results. Resolution response rates were 78.3% for the Astym group and 40.9% for the EE group. Astym subjects showed greater gains in DASH scores (p = 0.047 and in maximum grip strength (p = 0.008 than EE subjects. Astym therapy also resolved 20/21 (95.7% of the EE non-responders, who showed improvements in DASH scores (p < 0.005, pain with activity (p = 0.002, and function (p = 0.004 following Astym treatment. Gains continued at 6 and 12 months. No adverse effects were reported.Conclusion. This study

Effectiveness of Shockwave Treatment Combined With Eccentric Training for Patellar Tendinopathy: A Double-Blinded Randomized Study.

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Thijs, Karin M; Zwerver, Johannes; Backx, Frank J G; Steeneken, Victor; Rayer, Stephan; Groenenboom, Petra; Moen, Maarten H

2017-03-01

To evaluate the effectiveness of a combined treatment of focused shockwave therapy (ESWT) and eccentric training compared with sham-shockwave therapy (placebo) and eccentric training in participants with patellar tendinopathy (PT) after 24 weeks. Randomized controlled trial. Sports medicine departments of a university hospital and a general hospital in the Netherlands. Fifty-two physically active male and female participants with a clinical diagnosis of PT (mean age: 28.6 years; range, 18-45) were randomly allocated to the ESWT (n = 22) or sham shockwave (n = 30). Extracorporeal shockwave therapy and sham shockwave were applied in 3 sessions at 1-week intervals with a piezoelectric device. All participants were instructed to perform eccentric exercises (3 sets of 15 repetitions twice a day) for 3 months on a decline board at home. The Victorian Institute of Sport Assessment-Patella (VISA-P) scores (primary), pain scores during functional knee loading tests, and Likert score (secondary) were registered at baseline and at 6, 12, and 24 weeks after the start with the ESWT or sham-shockwave treatment. No significant differences for the primary and secondary outcome measures were found between the groups. In the ESWT/eccentric group, the VISA-P increased from 54.5 ± 15.4 to 70.9 ± 17.8, whereas the VISA-P in the sham-shockwave/eccentric group increased from 58.9 ± 14.6 to 78.2 ± 15.8 (between-group change in VISA-P at 24 weeks -4.8; 95% confidence interval, -12.7 to 3.0, P = 0.150). This study showed no additional effect of 3 sessions ESWT in participants with PT treated with eccentric exercises. The results should be interpreted with caution because of small sample size and considerable loss to follow-up, particularly in the ESWT group.

Preservation of eccentric strength in older adults: Evidence, mechanisms and implications for training and rehabilitation.

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Roig, Marc; Macintyre, Donna L; Eng, Janice J; Narici, Marco V; Maganaris, Constantinos N; Reid, W Darlene

2010-06-01

Overall reductions in muscle strength typically accompany the aging process. However, older adults show a relatively preserved capacity of producing eccentric strength. The preservation of eccentric strength in older adults is a well-established phenomenon, occurring indiscriminately across different muscle groups, independent of age-related architectural changes in muscle structure and velocity of movement. The mechanisms for the preservation of eccentric strength appear to be mechanical and cellular in origin and include both passive and active elements regulating muscle stiffness. The age-related accumulation of non-contractile material in the muscle-tendon unit increases passive stiffness, which might offer mechanical advantage during eccentric contractions. In addition, the preserved muscle tension and increased instantaneous stiffness of old muscle fibers during stretch increase active stiffness, which might enhance eccentric strength. The fact that the preservation of eccentric strength is present in people with chronic conditions when compared to age-matched healthy controls indicates that the aging process per se does not exclusively mediate the preservation of eccentric strength. Physical inactivity, which is common in elderly and people with chronic conditions, is a potential factor regulating the preservation of eccentric strength. When compared to concentric strength, the magnitude of preservation of eccentric strength in older adults ranges from 2% to 48% with a mean value of 21.6% from all studies. This functional reserve of eccentric strength might be clinically relevant, especially to initiate resistance training and rehabilitation programs in individuals with low levels of strength. 2010 Elsevier Inc. All rights reserved.

Postoperative eccentric macular holes after vitrectomy and internal limiting membrane peeling.

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Brouzas, Dimitrios; Dettoraki, Maria; Lavaris, Anastasios; Kourvetaris, Dimitrios; Nomikarios, Nikolaos; Moschos, Marilita M

2017-06-01

The purpose of this study was to describe the incidence, clinical characteristics, and outcome of eccentric macular holes presenting after vitrectomy and internal limiting membrane (ILM) peeling for the treatment of macular pathology and discuss the pathogenesis of holes formation. A retrospective, noncomparative, interventional case-series study of five patients who developed eccentric macular holes postoperatively following vitrectomy in 198 consecutive patients who underwent ILM peeling for idiopathic macular hole and epiretinal membrane formation between 2008 and 2015. Five patients (2.5 %) developed full-thickness eccentric macular holes postoperatively. Three patients presented with a single eccentric macular hole, one patient had an eccentric hole after a failed idiopathic macular hole surgery and one patient developed four eccentric macular holes. The mean diameter of the holes was 584 μm (range 206-1317 μm) and the average time of holes formation after vitrectomy was 27.7 weeks (range 1-140 weeks). Postoperative best-corrected visual acuity ranged from "counting fingers" to 20/25. The eyes with the holes distant from the fovea had the best final visual acuity. No further intervention was attempted and no complications occurred. The mean follow-up time was 26.8 months. The postoperative macular holes after vitrectomy and ILM peeling were variable in number, size, and time of appearance but remained stable and were not associated with any complications. The pathogenesis of macular holes is most consistent with contraction of the residual ILM or secondary epimacular proliferation probably stimulated by ILM peeling.

Eccentric pressurized tube for measuring creep rupture

International Nuclear Information System (INIS)

Schwab, P.R.

1981-01-01

Creep rupture is a long term failure mode in structural materials that occurs at high temperatures and moderate stress levels. The deterioration of the material preceding rupture, termed creep damage, manifests itself in the formation of small cavities on grain boundaries. To measure creep damage, sometimes uniaxial tests are performed, sometimes density measurements are made, and sometimes the grain boundary cavities are measured by microscopy techniques. The purpose of the present research is to explore a new method of measuring creep rupture, which involves measuring the curvature of eccentric pressurized tubes. Theoretical investigations as well as the design, construction, and operation of an experimental apparatus are included in this research

Effect of spaceflight on the spatial orientation of the vestibulo-ocular reflex during eccentric roll rotation: A case report.

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Reschke, Millard F; Wood, Scott J; Clément, Gilles

2018-01-01

Ground-based studies have reported shifts of the vestibulo-ocular reflex (VOR) slow phase velocity (SPV) axis toward the resultant gravito-inertial force vector. The VOR was examined during eccentric roll rotation before, during and after an 8-day orbital mission. On orbit this vector is aligned with the head z-axis. Our hypothesis was that eccentric roll rotation on orbit would generate horizontal eye movements. Two subjects were rotated in a semi-supine position with the head nasal-occipital axis parallel to the axis of rotation and 0.5 m off-center. The chair accelerated at 120 deg/s2 to 120 deg/s, rotated at constant velocity for one minute, and then decelerated to a stop in similar fashion. On Earth, the stimulation primarily generated torsional VOR. During spaceflight, in one subject torsional VOR became horizontal VOR, and then decayed very slowly. In the other subject, torsional VOR was reduced on orbit relative to pre- and post-flight, but the SPV axis did not rotate. We attribute the shift from torsional to horizontal VOR on orbit to a spatial orientation of velocity storage toward alignment with the gravito-inertial force vector, and the inter-individual difference to cognitive factors related to the subjective straight-ahead.

A Comparison of Exercise-Induced Muscle Damage Following Maximal Eccentric Contractions in Men and Boys.

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Deli, Chariklia K; Fatouros, Ioannis G; Paschalis, Vassilis; Georgakouli, Kalliopi; Zalavras, Athanasios; Avloniti, Alexandra; Koutedakis, Yiannis; Jamurtas, Athanasios Z

2017-08-01

Research regarding exercise-induced muscle-damage mainly focuses on adults. The present study examined exercise-induced muscle-damage responses in adults compared with children. Eleven healthy boys (10-12 y) and 15 healthy men (18-45 y) performed 5 sets of 15 maximal eccentric contractions of the knee extensors. Range of motion (ROM), delayed onset muscle soreness (DOMS) during squat and walking, and peak isometric, concentric and eccentric torque were assessed before, post, 24, 48, 72, and 96 hr postexercise. Creatine kinase (CK) activity was assessed before and 72 hr postexercise. Eccentric exercise resulted in DOMS during squat that persisted for up to 96h in men, and 48 hr in boys (p < .05), and DOMS during walking that persisted for up to 72 hr in men, and 48 hr in boys (p < .01). The ROM was lower in both age groups 48 hr postexercise (p < .001). Isometric (p < .001), concentric (p < .01) and eccentric (p < .01) force decreased post, and up to 48 hr postexercise in men. Except for a reduction in isometric force immediately after exercise, no other changes occurred in boys' isokinetic force. CK activity increased in men at 72 hr postexercise compared with pre exercise levels (p = .05). Our data provide further confirmation that children are less susceptible to exercise-induced muscle damage compared with adults.

Eccentric connectivity index of chemical trees

International Nuclear Information System (INIS)

Haoer, R. S.; Atan, K. A.; Said, M. R. Md.; Khalaf, A. M.; Hasni, R.

2016-01-01

Let G = (V, E) be a simple connected molecular graph. In such a simple molecular graph, vertices and edges are depicted atoms and chemical bonds respectively, we refer to the sets of vertices by V (G) and edges by E (G). If d(u, v) be distance between two vertices u, v ∈ V(G) and can be defined as the length of a shortest path joining them. Then, the eccentricity connectivity index (ECI) of a molecular graph G is ξ(G) = ∑_v_∈_V_(_G_) d(v) ec(v), where d(v) is degree of a vertex v ∈ V(G). ec(v) is the length of a greatest path linking to another vertex of v. In this study, we focus the general formula for the eccentricity connectivity index (ECI) of some chemical trees as alkenes.

An Eccentrically Biased Rehabilitation Program Early after TKA Surgery

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Robin L. Marcus

2011-01-01

Full Text Available Rehabilitation services are less-studied aspects of the management following total knee arthroplasty (TKA despite long-term suboptimal physical functioning and chronic deficits in muscle function. This paper describes the preliminary findings of a six-week (12 session eccentrically-biased rehabilitation program targeted at deficits in physical function and muscle function, initiated one month following surgery. A quasiexperimental, one group, pretest-posttest study with thirteen individuals (6 female, 7 male; mean age 57±7 years examined the effectiveness of an eccentrically-biased rehabilitation program. The program resulted in improvements in the primary physical function endpoints (SF-36 physical component summary and the six-minute walk test with increases of 59% and 47%, respectively. Muscle function endpoints (knee extension strength and power also increased 107% and 93%, respectively. Eccentrically-biased exercise used as an addition to rehabilitation may help amplify and accelerate physical function following TKA surgery.

EFFECTS OF A 4-WEEK ECCENTRIC TRAINING PROGRAM ON THE REPEATED BOUT EFFECT IN YOUNG ACTIVE WOMEN

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Rodrigo Fernandez-Gonzalo

2011-12-01

Full Text Available The aim of this study was to analyze the responses of women to the repeated bout effect (RBE and to a short eccentric training program. Twenty-four young females were randomly assigned to a training group (TG, n = 14 or a control group (CG, n = 10. They performed two identical acute eccentric bouts (120 repetitions at 70% of 1RM in a leg-press device in an 8 weeks interval. TG followed a 4-week-eccentric-training program between the bouts. Maximal isometric contraction, range of motion, peak power and quadriceps muscle soreness were compared between and within groups before and after the two acute eccentric bouts. TG and CG presented significant losses of isometric strength and peak power, and an increment in soreness after the first bout. Isometric strength and peak power were recovered faster in CG after the second bout (p < 0.05 compared with TG, which showed a similar recovery of these parameters after the second bout compared with the first one. A decrease in soreness and a faster recovery of range of motion were found in TG (p < 0.05 following the second bout compared with the first one, but not in CG. Data indicate that a 4-week eccentric training program may prevent the RBE over those adaptations related with muscle damage (e.g. strength loss, but it may increase RBE impact on inflammatory processes (e.g. soreness.

Effect of eccentric exercise program for early tibialis posterior tendinopathy.

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Kulig, Kornelia; Lederhaus, Eric S; Reischl, Steve; Arya, Shruti; Bashford, Greg

2009-09-01

Morphology and vascularization of painful tibialis posterior (TP) tendons before and after an intervention targeting the degenerated tendon were examined. Functional status and pain level were also assessed. A10-week twice daily, progressive eccentric tendon loading, calf stretching program with orthoses was implemented with ten, early stage TP tendinopathy subjects. TP tendons were imaged by grayscale and Doppler ultrasound at INITIAL and POST evaluations to assess the tendon's morphology and signs of neovascularization. The Foot Functional Index (FFI), Physical Activity Scale (PAS), 5-Minute Walk Test, and single heel raise (SHR) test were completed at INITIAL and POST evaluations. The Global Rating Scale (GRS) was completed at 6 months followup. One-way ANOVA was used to compare the FFI at INITIAL, POST, and 6-MONTH time points. Paired t-tests were used to compare means between the remaining variables. The level of significance was p = 0.05. There was a significant difference in FFI total, pain, and disability at the three time-points. Post-hoc paired t-tests revealed that the FFI scores were lower for the total score and pain and disability subcategories when comparing from INITIAL to POST and INITIAL to 6-MONTH evaluations (p Tendon morphology and vascularization remained abnormal following the intervention. A 10-week tendon specific eccentric program resulted in improvements in symptoms and function without changes in tendon morphology or neovascularization.

Eccentric muscle challenge shows osteopontin polymorphism modulation of muscle damage.

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Barfield, Whitney L; Uaesoontrachoon, Kitipong; Wu, Chung-Sheih; Lin, Stephen; Chen, Yue; Wang, Paul C; Kanaan, Yasmine; Bond, Vernon; Hoffman, Eric P

2014-08-01

A promoter polymorphism of the osteopontin (OPN) gene (rs28357094) has been associated with multiple inflammatory states, severity of Duchenne muscular dystrophy (DMD) and muscle size in healthy young adults. We sought to define the mechanism of action of the polymorphism, using allele-specific in vitro reporter assays in muscle cells, and a genotype-stratified intervention in healthy controls. In vitro reporter constructs showed the G allele to respond to estrogen treatment, whereas the T allele showed no transcriptional response. Young adult volunteers (n = 187) were enrolled into a baseline study, and subjects with specific rs28357094 genotypes enrolled into an eccentric muscle challenge intervention [n = 3 TT; n = 3 GG/GT (dominant inheritance model)]. Female volunteers carrying the G allele showed significantly greater inflammation and increased muscle volume change as determined by magnetic resonance imaging T1- and T2-weighted images after eccentric challenge, as well as greater decrement in biceps muscle force. Our data suggest a model where the G allele enables enhanced activities of upstream enhancer elements due to loss of Sp1 binding at the polymorphic site. This results in significantly greater expression of the pro-inflammatory OPN cytokine during tissue remodeling in response to challenge in G allele carriers, promoting muscle hypertrophy in normal females, but increased damage in DMD patients. © The Author 2014. Published by Oxford University Press.

Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis

DEFF Research Database (Denmark)

Langberg, Henning; Ellingsgaard, Helga; Madsen, Thomas

2007-01-01

It has been shown that 12 weeks of eccentric heavy resistance training can reduce pain in runners suffering from chronic Achilles tendinosis, but the mechanism behind the effectiveness of this treatment is unknown. The present study investigates the local effect of an eccentric training regime on...... in the healthy tendons. The clinical effect of the 12 weeks of eccentric training was determined by using a standardized loading procedure of the Achilles tendons showing a decrease in pain in all the chronic injured tendons (VAS before 44+/-9, after 13+/-9; P......It has been shown that 12 weeks of eccentric heavy resistance training can reduce pain in runners suffering from chronic Achilles tendinosis, but the mechanism behind the effectiveness of this treatment is unknown. The present study investigates the local effect of an eccentric training regime...... of heavy-resistance eccentric training apart from their regular training and soccer activity. Before and after the training period the tissue concentration of indicators of collagen turnover was measured by the use of the microdialysis technique. After training, collagen synthesis was increased...

HAMSTRING INJURY REHABILITATION AND PREVENTION OF REINJURY USING LENGTHENED STATE ECCENTRIC TRAINING: A NEW CONCEPT

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Tim, Tyler; McHugh, Malachy

2012-01-01

Back ground and Purpose: Hamstring injury is a common occurrence in sport and there has been limited success in reducing this rate of recurrence to date. Description of Topic with Related Evidence: High speed running requires eccentric strength when the hamstring muscles are in a lengthened state. The lengthened state occurs when the hip is in flexion and the lower leg moves into extension, thus lengthening the two joint hamstring muscle over both articulations upon which they act. There is evidence to suggest that athletes who have sustained a hamstring strain lack strength when the muscle is utilized during performance in a lengthened state. Purpose: To examine the risk factors contributing to such a high recurrence rate and propose a unique rehabilitation strategy addressing these factors in order to decrease the rate of reinjury. Discussion/Relation to Clinical Practice: Failing to increase an athlete's eccentric strength in a lengthened position after a hamstring injury may predispose an athlete to subsequent reinjury. Incorporating lengthened state eccentric training may help reduce the rate of reinjury. Level of Evidence: Level 5 PMID:22666648

The Use of Session RPE to Monitor the Intensity of Weight Training in Older Women: Acute Responses to Eccentric, Concentric, and Dynamic Exercises

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Sandro S. Ferreira

2014-01-01

Full Text Available The rating of perceived exertion (RPE is ability to detect and interpret organic sensations while performing exercises. This method has been used to measure the level of effort that is felt during weight-training at a given intensity. The purpose of this investigation was to compare session RPE values with those of traditional RPE measurements for different weight-training muscle actions, performed together or separately. Fourteen women with no former weight-training experience were recruited for the investigation. All participants completed five sessions of exercise: familiarization, maximum force, concentric-only (CONC-only, eccentric-only (ECC-only, and dynamic (DYN = CONC + ECC. The traditional RPE method was measured after each series of exercises, and the session RPE was measured 30 min after the end of the training session. The statistical analyses used were the paired t-test, one-way analysis of variance, and repeated measures analysis of variance. Significant differences between traditional RPE and session RPE for DYN, CONC, and ECC exercises were not found. This investigation demonstrated that session RPE is similar to traditional RPE in terms of weight-training involving concentric, eccentric, or dynamic muscle exercises, and that it can be used to prescribe and monitor weight-training sessions in older subjects.

Development of a new universal machine device for eccentric shafts processing

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Михайло Володимирович Маргуліс

2015-11-01

Full Text Available The analysis of the existing lathe devices for machining of eccentric details and the reasons for the development of a new universal machine device– a shifting lathe center-have been described in the article. The device design, its operating principle, the main parts functions and elements of the case were described and illustrated One of the most complicated cases of eccentric shaft turning, that is turning design and scheme of the eccentric shaft of precessional harmonic drive with intermediate rolling bodies when the proposed device was used was described in the article. The shifting lathe center can reduce the complexity of the machine tool for turning eccentric shafts configuration. The ability to install the shifting center in the tailstock and headstock of the lathe, and the availability of the leash makes it possible to turn various eccentric parts, conical surfaces, to apply the device to compensate for the emerging taper in cylindrical shafts processing. All the above mentioned makes the device universal. The specific feature of this device is the use of a ball center and the connection of the centering element with the adjusting screw by a fine thread screw, this increasing the precision machining. The protective cover of the device makes it possible to reduce the chance of possible injury from protruding parts of the device, namely the leash and the centering element

Dynamic response characteristics of the high-temperature superconducting maglev system under lateral eccentric distance

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Wang, Bo; Zheng, Jun; Si, Shuaishuai; Qian, Nan; Li, Haitao; Li, Jipeng; Deng, Zigang

2016-07-01

Off-centre operation of high-temperature superconducting (HTS) maglev systems caused by inevitable conditions such as the misregistration of vehicle, crosswind and curve negotiation, may change the distribution of the trapped flux in the HTS bulks and the magnetic interaction between HTS bulks and the PMG. It impacts on the performance of HTS maglev, and more seriously makes the maglev vehicle overturned. Therefore, understanding the performance of the HTS maglev in off-center operation is very important. In this paper, the dynamic response characteristics of a cryostat with twenty-four onboard YBaCuO superconductor bulks were experimentally investigated at different eccentric distances under loads before the initial FC process. Parameters such as vibration accelerations, displacement, natural frequency and dynamic stiffness were acquired and analyzed via the B&K vibration analyzer and laser displacement sensors. Results suggest that the natural frequency and dynamic stiffness of the maglev vehicle would be obviously reduced with the eccentric distance, posing negative effects on the stability of HTS maglev.

Eccentric Exercise, Kinesiology Tape, and Balance in Healthy Men.

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Hosp, Simona; Folie, Ramona; Csapo, Robert; Hasler, Michael; Nachbauer, Werner

2017-07-01

  Deficits in balance have been identified as a possible risk factor for knee injuries in athletes. Despite a lack of evidence for its effectiveness, kinesiology tape (KT) is widely used to prevent knee injuries.   To investigate the influence of KT at the knee joint on balance ability in healthy men after eccentric exercise.   Crossover study.   University laboratory.   Twelve young men with no history of lower limb injury volunteered for the study (age = 23.3 ± 2.6 years). All participants were students enrolled in a sports science program.   Participants performed the balance test with and without KT at the knee joint on 2 separate days.   The ability to maintain balance was assessed during a single-legged-stance test using a computerized balance-stability test system. The test was performed before and after 30 minutes of downhill walking on a treadmill.   Eccentric exercise resulted in a deterioration of balance ability, which was attenuated by the use of KT. Further analyses revealed that the effectiveness of KT depended on the participant's balance status, with the preventive effect being greater in participants presenting with poorer baseline balance ability.   Applied to the knee joint, KT counteracted the exercise-related deterioration of balance ability observed when no tape was used. Participants presenting with below-average balance ability received more benefit from KT. By preventing exercise-related impairment of balance ability, KT might help to reduce the risk of sport-associated knee injuries.

An Intelligent Harmonic Synthesis Technique for Air-Gap Eccentricity Fault Diagnosis in Induction Motors

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Li, De Z.; Wang, Wilson; Ismail, Fathy

2017-11-01

Induction motors (IMs) are commonly used in various industrial applications. To improve energy consumption efficiency, a reliable IM health condition monitoring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is proposed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are synthesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air-gap eccentricity diagnosis. The effectiveness of the proposed harmonic synthesis technique is examined experimentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.

Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

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Kamanli, Mehmet; Unal, Alptug

2017-10-01

After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

EFFECTS OF CONCENTRIC AND ECCENTRIC MUSCLE ACTIONS ON SERUM MYOSTATIN AND FOLLISTATIN-LIKE RELATED GENE LEVELS

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Lemuel Taylor

2004-12-01

Full Text Available The present study determined the effects of concentric and eccentric muscle actions on the contents of serum myostatin and follistatin-like related gene (FLRG. Eight untrained males performed one exercise bout with each leg, separated by three weeks. One bout consisted of 7 sets of 10 repetitions of eccentric muscle actions of the knee extensors at 150% of the concentric 1-RM while the other bout consisted of 7 sets of 10 repetitions of concentric muscle actions at 75% 1-RM. The legs used and the bouts performed were randomized. Five days prior to each exercise bout, baseline measurements were taken for muscle strength. For both bouts, a venous blood sample was obtained immediately prior to exercise and again at 6, 24, and 48 hr post-exercise. Data were analyzed with 2 X 4 (bout x test ANOVA (p < 0.05. Increases in serum myostatin and FLRG occurred with each exercise bout and, excluding 48 hr post-exercise, were significantly correlated to one another (p < 0.05. After eccentric exercise, peak increases of 68% and 50% (p < 0.05 were observed for myostatin and FLRG, respectively. Similar increases of 54% and 44% (p < 0.05 were observed after concentric muscle actions. There was no significant difference in expression of myostatin or FLRG as a function of muscle action type. Our results suggest that a single bout of exercise with either eccentric or concentric muscle actions appear to elicit a similar increase in serum myostatin and FLRG. Therefore, the type of muscle action may not be as much a mitigating factor for increasing serum myostatin and FLRG rather than the muscle action per se.

Unaccustomed eccentric contractions impair plasma K+ regulation in the absence of changes in muscle Na+,K+-ATPase content.

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Craig A Goodman

Full Text Available The Na+,K+-ATPase (NKA plays a fundamental role in the regulation of skeletal muscle membrane Na+ and K+ gradients, excitability and fatigue during repeated intense contractions. Many studies have investigated the effects of acute concentric exercise on K+ regulation and skeletal muscle NKA, but almost nothing is known about the effects of repeated eccentric contractions. We therefore investigated the effects of unaccustomed maximal eccentric knee extensor contractions on K+ regulation during exercise, peak knee extensor muscle torque, and vastus lateralis muscle NKA content and 3-O-MFPase activity. Torque measurements, muscle biopsies, and venous blood samples were taken before, during and up to 7 days following the contractions in six healthy adults. Eccentric contractions reduced peak isometric muscle torque immediately post-exercise by 26±11% and serum creatine kinase concentration peaked 24 h post-exercise at 339±90 IU/L. During eccentric contractions, plasma [K+] rose during Set 1 and remained elevated at ∼4.9 mM during sets 4-10; this was despite a decline in work output by Set 4, which fell by 18.9% at set 10. The rise in plasma [K+] x work(-1 ratio was elevated over Set 2 from Set 4- Set 10. Eccentric contractions had no effect on muscle NKA content or maximal in-vitro 3-O-MFPase activity immediately post- or up to 7 d post-exercise. The sustained elevation in plasma [K+] despite a decrease in work performed by the knee extensor muscles suggests an impairment in K+ regulation during maximal eccentric contractions, possibly due to increased plasma membrane permeability or to excitation-contraction uncoupling.

Effect of deep stripping massage alone or with eccentric resistance on hamstring length and strength.

Science.gov (United States)

Forman, Jeffrey; Geertsen, Lisbeth; Rogers, Michael E

2014-01-01

Many studies have evaluated the effects of different interventions on hamstring length. However, little research has been conducted on the effects of deep stripping massage strokes (DSMS) alone, or combined with eccentric resistance, on hamstring length and strength. To determine: 1) if DSMS have an effect on hamstring length and strength and 2) if the effects on hamstring length and strength are any different when DSMS are combined with eccentric exercise. 89 Community College students and community members between the ages of 18 and 62 volunteered for the study. Of these, 64 demonstrated tight hamstrings on either one or both sides as defined by supine, passive terminal knee extension of ≤75° and participated in the study. Strength was assessed by pressing the posterior calcaneus into a strain gauge for approximately 5 s while seated with the knee flexed to 90°. On their tighter side, participants were administered longitudinal DSMS during 15, 10-s bouts of eccentric resistance with an elastic resistance band. On their other hamstring, participants were administered 15, 10-s longitudinal DSMS while lying passive. All massage strokes were performed at a depth of 7 out of 10 on a verbal pressure scale index. Afterwards, the hamstring flexibility and strength tests were repeated. Both DSMS with eccentric resistance (10.7%) and DSMS alone (6.3%) resulted in improved (p alone. Strength was not significantly affected by either treatment. These results suggest that DSMS increases hamstring length in less than 3 min but has no affect on strength. Furthermore, combining DSMS with eccentric resistance produces more hamstring flexibility gains than DSMS alone and does not affect strength. Copyright © 2013 Elsevier Ltd. All rights reserved.

Methods for determining the carrying capacity of eccentrically compressed concrete elements

Directory of Open Access Journals (Sweden)

Starishko Ivan Nikolaevich

2014-04-01

Full Text Available The author presents the results of calculations of eccentrically compressed elements in the ultimate limit state of bearing capacity, taking into account all possiblestresses in the longitudinal reinforcement from the R to the R , caused by different values of eccentricity longitudinal force. The method of calculation is based on the simultaneous solution of the equilibrium equations of the longitudinal forces and internal forces with the equilibrium equations of bending moments in the ultimate limit state of the normal sections. Simultaneous solution of these equations, as well as additional equations, reflecting the stress-strain limit state elements, leads to the solution of a cubic equation with respect to height of uncracked concrete, or with respect to the carrying capacity. According to the author it is a significant advantage over the existing methods, in which the equilibrium equations using longitudinal forces obtained one value of the height, and the equilibrium equations of bending moments - another. Theoretical studies of the author, in this article and the reasons to calculate specific examples showed that a decrease in the eccentricity of the longitudinal force in the limiting state of eccentrically compressed concrete elements height uncracked concrete height increases, the tension in the longitudinal reinforcement area gradually (not abruptly goes from a state of tension compression, and load-bearing capacity of elements it increases, which is also confirmed by the experimental results. Designed journalist calculations of eccentrically compressed elements for 4 cases of eccentric compression, instead of 2 - as set out in the regulations, fully cover the entire spectrum of possible cases of the stress-strain limit state elements that comply with the European standards for reinforced concrete, in particular Eurocode 2 (2003.

Whey protein supplementation accelerates satellite cell proliferation during recovery from eccentric exercise

DEFF Research Database (Denmark)

Farup, Jean; Rahbek, Stine Klejs; Knudsen, Inge Skovgaard

2014-01-01

well investigated. In a comparative human study, we investigated the effect of hydrolyzed whey protein supplementation following eccentric exercise on fiber type-specific SC accumulation. Twenty-four young healthy subjects received either hydrolyzed whey protein + carbohydrate (whey, n = 12) or iso...... creatine kinase (CK) were evaluated as indices of recovery from muscle damage. In type II fiber-associated SCs, the whey group increased SCs/fiber from 0.05 [0.02; 0.07] to 0.09 [0.06; 0.12] (p ... the placebo group (p whey group increased SCs/myonuclei from 4 % [2; 5] to 10 % [4; 16] (p 

THE EFFECTS OF RACKET INERTIA TENSOR ON ELBOW LOADINGS AND RACKET BEHAVIOR FOR CENTRAL AND ECCENTRIC IMPACTS

Directory of Open Access Journals (Sweden)

Steven M. Nesbit

2006-06-01

Full Text Available This paper discusses the inertia tensors of tennis rackets and their influence on the elbow swing torques in a forehand motion, the loadings transmitted to the elbow from central and eccentric impacts, and the racket acceleration responses from central and eccentric impacts. Inertia tensors of various rackets with similar mass and mass center location were determined by an inertia pendulum and were found to vary considerably in all three orthogonal directions. Tennis swing mechanics and impact analyses were performed using a computer model comprised of a full-body model of a human, a parametric model of the racket, and an impact function. The swing mechanics analysis of a forehand motion determined that inertia values had a moderate linear effect on the pronation-supination elbow torques required to twist the racket, and a minor effect on the flexion-extension and valgus-varus torques. The impact analysis found that mass center inertia values had a considerable effect on the transmitted torques for both longitudinal and latitudinal eccentric impacts and significantly affected all elbow torque components. Racket acceleration responses to central and eccentric impacts were measured experimentally and found to be notably sensitive to impact location and mass center inertia values

Static Eccentricity Fault Recognition in Three-Phase Line Start Permanent Magnet Synchronous Motor Using Finite Element Method

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Mahdi Karami

2014-01-01

Full Text Available This paper is dedicated to investigating static eccentricity in a three-phase LSPMSM. The modeling of LSPMSM with static eccentricity between stator and rotor is developed using finite element method (FEM. The analytical expression for the permeance and flux components of nonuniform air-gap due to static eccentricity fault is discussed. Various indexes for static eccentricity detection using stator current signal of IM and permanent magnet synchronous motor (PMSM are presented. Since LSPMSM is composed of a rotor which is a combination of these two motors, the ability of these features is evaluated for static eccentricity diagnosis in LSPMSM. The simulated stator current signal of LSPMSM in the presence of static eccentricity is analyzed in frequency domain using power spectral density (PSD. It is demonstrated that static eccentricity fault generates a series of low frequency harmonic components in the form of sidebands around the fundamental frequency. Moreover, the amplitudes of these components increase in proportion to the fault severity. According to the mentioned observations, an accurate frequency pattern is specified for static eccentricity detection in three-phase LSPMSM.

BounceBack™ capsules for reduction of DOMS after eccentric exercise: a randomized, double-blind, placebo-controlled, crossover pilot study

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Singh Betsy B

2009-06-01

Full Text Available Abstract Background Delayed onset muscle soreness (DOMS is muscle pain and discomfort experienced approximately one to three days after exercise. DOMS is thought to be a result of microscopic muscle fiber tears that occur more commonly after eccentric exercise rather than concentric exercise. This study sought to test the efficacy of a proprietary dietary supplement, BounceBack™, to alleviate the severity of DOMS after standardized eccentric exercise. Methods The study was a randomized, double-blind, placebo-controlled, crossover study. Ten healthy community-dwelling untrained subjects, ranging in age from 18–45 years, were enrolled. Mean differences within and between groups were assessed inferentially at each data collection time-point using t-tests for all outcome measures. Results In this controlled pilot study, intake of BounceBack™ capsules for 30 days resulted in a significant reduction in standardized measures of pain and tenderness post-eccentric exercise compared to the placebo group. There were trends towards reductions in plasma indicators of inflammation (high sensitivity C-reactive protein and muscle damage (creatine phosphokinase and myoglobin. Conclusion BounceBack™ capsules were able to significantly reduce standardized measures of pain and tenderness at several post-eccentric exercise time points in comparison to placebo. The differences in the serological markers of DOMS, while not statistically significant, appear to support the clinical findings. The product appears to have a good safety profile and further study with a larger sample size is warranted based on the current results.

BounceBack capsules for reduction of DOMS after eccentric exercise: a randomized, double-blind, placebo-controlled, crossover pilot study.

Science.gov (United States)

Udani, Jay K; Singh, Betsy B; Singh, Vijay J; Sandoval, Elizabeth

2009-06-05

Delayed onset muscle soreness (DOMS) is muscle pain and discomfort experienced approximately one to three days after exercise. DOMS is thought to be a result of microscopic muscle fiber tears that occur more commonly after eccentric exercise rather than concentric exercise. This study sought to test the efficacy of a proprietary dietary supplement, BounceBack, to alleviate the severity of DOMS after standardized eccentric exercise. The study was a randomized, double-blind, placebo-controlled, crossover study. Ten healthy community-dwelling untrained subjects, ranging in age from 18-45 years, were enrolled. Mean differences within and between groups were assessed inferentially at each data collection time-point using t-tests for all outcome measures. In this controlled pilot study, intake of BounceBack capsules for 30 days resulted in a significant reduction in standardized measures of pain and tenderness post-eccentric exercise compared to the placebo group. There were trends towards reductions in plasma indicators of inflammation (high sensitivity C-reactive protein) and muscle damage (creatine phosphokinase and myoglobin). BounceBack capsules were able to significantly reduce standardized measures of pain and tenderness at several post-eccentric exercise time points in comparison to placebo. The differences in the serological markers of DOMS, while not statistically significant, appear to support the clinical findings. The product appears to have a good safety profile and further study with a larger sample size is warranted based on the current results.

BounceBack™ capsules for reduction of DOMS after eccentric exercise: a randomized, double-blind, placebo-controlled, crossover pilot study

Science.gov (United States)

Udani, Jay K; Singh, Betsy B; Singh, Vijay J; Sandoval, Elizabeth

2009-01-01

Background Delayed onset muscle soreness (DOMS) is muscle pain and discomfort experienced approximately one to three days after exercise. DOMS is thought to be a result of microscopic muscle fiber tears that occur more commonly after eccentric exercise rather than concentric exercise. This study sought to test the efficacy of a proprietary dietary supplement, BounceBack™, to alleviate the severity of DOMS after standardized eccentric exercise. Methods The study was a randomized, double-blind, placebo-controlled, crossover study. Ten healthy community-dwelling untrained subjects, ranging in age from 18–45 years, were enrolled. Mean differences within and between groups were assessed inferentially at each data collection time-point using t-tests for all outcome measures. Results In this controlled pilot study, intake of BounceBack™ capsules for 30 days resulted in a significant reduction in standardized measures of pain and tenderness post-eccentric exercise compared to the placebo group. There were trends towards reductions in plasma indicators of inflammation (high sensitivity C-reactive protein) and muscle damage (creatine phosphokinase and myoglobin). Conclusion BounceBack™ capsules were able to significantly reduce standardized measures of pain and tenderness at several post-eccentric exercise time points in comparison to placebo. The differences in the serological markers of DOMS, while not statistically significant, appear to support the clinical findings. The product appears to have a good safety profile and further study with a larger sample size is warranted based on the current results. PMID:19500355

Effect of eccentric exercise on the healing process of injured patellar tendon in rats

OpenAIRE

Nakamura, Kenichi; Kitaoka, Katsuhiko; Tomita, Katsuro

2008-01-01

Background. Earlier studies have reported positive results from eccentric training in patients with tendon disorders. The reasons for the beneficial clinical effects of eccentric training are not known. Vascularization followed by regression of the vasculature enhances the healing response of injured tendons. Eccentric exercise induces a more beneficial healing response than concentric exercise. Methods. Sixty rats with patellar tendon injuries were divided into three groups: nonexercise cont...

Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

Directory of Open Access Journals (Sweden)

Kamanli Mehmet

2017-01-01

Full Text Available After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

A complete waveform model for compact binaries on eccentric orbits

Science.gov (United States)

George, Daniel; Huerta, Eliu; Kumar, Prayush; Agarwal, Bhanu; Schive, Hsi-Yu; Pfeiffer, Harald; Chu, Tony; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela

2017-01-01

We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are non-spinning, and which evolve on orbits with low to moderate eccentricity. We show that this inspiral-merger-ringdown waveform model reproduces the effective-one-body model for black hole binaries with mass-ratios between 1 to 15 in the zero eccentricity limit over a wide range of the parameter space under consideration. We use this model to show that the gravitational wave transients GW150914 and GW151226 can be effectively recovered with template banks of quasicircular, spin-aligned waveforms if the eccentricity e0 of these systems when they enter the aLIGO band at a gravitational wave frequency of 14 Hz satisfies e0GW 150914 <= 0 . 15 and e0GW 151226 <= 0 . 1 .

Waveform model for an eccentric binary black hole based on the effective-one-body-numerical-relativity formalism

Science.gov (United States)

Cao, Zhoujian; Han, Wen-Biao

2017-08-01

Binary black hole systems are among the most important sources for gravitational wave detection. They are also good objects for theoretical research for general relativity. A gravitational waveform template is important to data analysis. An effective-one-body-numerical-relativity (EOBNR) model has played an essential role in the LIGO data analysis. For future space-based gravitational wave detection, many binary systems will admit a somewhat orbit eccentricity. At the same time, the eccentric binary is also an interesting topic for theoretical study in general relativity. In this paper, we construct the first eccentric binary waveform model based on an effective-one-body-numerical-relativity framework. Our basic assumption in the model construction is that the involved eccentricity is small. We have compared our eccentric EOBNR model to the circular one used in the LIGO data analysis. We have also tested our eccentric EOBNR model against another recently proposed eccentric binary waveform model; against numerical relativity simulation results; and against perturbation approximation results for extreme mass ratio binary systems. Compared to numerical relativity simulations with an eccentricity as large as about 0.2, the overlap factor for our eccentric EOBNR model is better than 0.98 for all tested cases, including spinless binary and spinning binary, equal mass binary, and unequal mass binary. Hopefully, our eccentric model can be the starting point to develop a faithful template for future space-based gravitational wave detectors.

Foveal cone spacing and cone photopigment density difference: objective measurements in the same subjects.

Science.gov (United States)

Marcos, S; Tornow, R P; Elsner, A E; Navarro, R

1997-07-01

Foveal cone spacing was measured in vivo using an objective technique: ocular speckle interferometry. Cone packing density was computed from cone spacing data. Foveal cone photopigment density difference was measured in the same subjects using retinal densitometry with a scanning laser ophthalmoscope. Both the cone packing density and cone photopigment density difference decreased sharply with increasing retinal eccentricity. From the comparison of both sets of measurements, the computed amounts of photopigment per cone increased slightly with increasing retinal eccentricity. Consistent with previous results, decreases in cone outer segment length are over-compensated by an increase in the outer segment area, at least in retinal eccentricities up to 1 deg.

Review of pump suction reducer selection: Eccentric or concentric reducers

OpenAIRE

Mahaffey, R M; van Vuuren, S J

2014-01-01

Eccentric reducers are traditionally recommended for the pump suction reducer fitting to allow for transportation of air through the fitting to the pump. The ability of a concentric reducer to provide an improved approach flow to the pump while still allowing air to be transported through the fitting is investigated. Computational fluid dynamics (CFD) were utilised to analyse six concentric and six eccentric reducer geometries at four different inlet velocities to determine the flow velocity ...

Comparative study of two protocols of eccentric exercise on knee pain and function in athletes with patellar tendinopathy: randomized controlled study

OpenAIRE

Cunha, Ronaldo Alves da; Dias, Andreia Natacha; Santos, Marcelo Bannwart; Lopes, Alexandre Dias

2012-01-01

INTRODUCTION: The eccentric squat on a slope has been proved effective in conservative treatment of patellar tendinopathy, especially in the athletic population. However, several aspects such as intensity and pain during therapy still differ among authors. OBJECTIVES: To compare the effectiveness of two protocols of eccentric exercise (performed with and without pain), in the improvement of knee function and pain intensity in athletes with patellar tendinopathy. METHODS: 7 athletes of both ge...

Effects of In-Season Inertial Resistance Training With Eccentric Overload in a Sports Population at Risk for Patellar Tendinopathy.

Science.gov (United States)

Gual, Gabriel; Fort-Vanmeerhaeghe, Azahara; Romero-Rodríguez, Daniel; Tesch, Per A

2016-07-01

Gual, G, Fort-Vanmeerhaeghe, A, Romero-Rodríguez, D, and Tesch, PA. Effects of in-season inertial resistance training with eccentric overload in a sports population at risk for patellar tendinopathy. J Strength Cond Res 30(7): 1834-1842, 2016-Volleyball and basketball players can be considered as a population at risk for patellar tendinopathy. Given the paradox that eccentric training elicits therapeutic benefits yet might provoke such injury, we investigated the influence of a weekly bout of inertial squat resistance exercise offering eccentric overload on lower limb muscle power and patellar tendon complaints. Players of 8 (4 basketball and 4 volleyball) teams (38 women and 43 men) were randomly assigned to either the intervention (IG) or control (CG) group. Although IG and CG maintained scheduled in-season training routines over 24 weeks, IG, in addition, performed 1 weekly session of eccentric overload by 4 sets of 8 repetitions of the squat using flywheel inertial resistance. Victorian Institute of Sports Assessment patellar tendinopathy questionnaire (VISA-p), vertical countermovement jump, and squat power, both concentric (Squat-Con) and eccentric (Squat-Ecc), tests were performed before (T1), during (T2), and after (T3) the 24 weeks of intervention. Neither group suffered from patellar tendinopathy during the study period. VISA-p displayed no differences across groups at any measurement period. Countermovement jump scores significantly (p ≤ 0.05) differed between groups in favor of the IG. Both Squat-Con and Squat-Ecc mean scores from the IG were significantly (p training bout to a regular basketball and volleyball exercise routine enhances lower limb muscle power without triggering patellar tendon complaints. Future studies, using the current exercise paradigm, aim to explore its efficacy to prevent or combat patellar tendinopathy in sports calling for frequent explosive jumps.

A discussion of the eccentric binary hypothesis for transient X-ray sources

International Nuclear Information System (INIS)

Avni, Y.; Goldman, I.

1979-01-01

The eccentric binary hypothesis for transient x-ray sources in the framework of the gradual acceleration stellar wind model proposed by Barlow and Cohen is examined. It is found that a consideration of the ratio of maximum to minimum luminosities and of the ratio of the durations of the high and low states, for a typical transient x-ray source, yields a rather high eccentricity, despite the gradual acceleration of the wind. When typical physical parameters for the binary members are taken into account, we find that a consistent description is possible only for very eccentric orbits (e>=0.9), thus the model is inadequate as a general explanation of the x-ray transient phenomenon. The recurrent transient x-ray source 4U 1630-47, which was considered in ihe past to be a realization of the eccentric binary model is studied and it is demonstrated that it cannot be described consistently within the framework of the model, unless the optical primary is very peculiar. (author)

Interseason variability in isokinetic strength and poor correlation with Nordic hamstring eccentric strength in football players.

Science.gov (United States)

van Dyk, N; Witvrouw, E; Bahr, R

2018-04-25

In elite sport, the use of strength testing to establish muscle function and performance is common. Traditionally, isokinetic strength tests have been used, measuring torque during concentric and eccentric muscle action. A device that measures eccentric hamstring muscle strength while performing the Nordic hamstring exercise is now also frequently used. The study aimed to investigate the variability of isokinetic muscle strength over time, for example, between seasons, and the relationship between isokinetic testing and the new Nordic hamstring exercise device. All teams (n = 18) eligible to compete in the premier football league in Qatar underwent a comprehensive strength assessment during their periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Qatar. Isokinetic strength was investigated for measurement error, and correlated to Nordic hamstring exercise strength. Of the 529 players included, 288 players had repeated tests with 1/2 seasons between test occasions. Variability (measurement error) between test occasions was substantial, as demonstrated by the measurement error (approximately 25 Nm, 15%), whether separated by 1 or 2 seasons. Considering hamstring injuries, the same pattern was observed among injured (n = 60) and uninjured (n = 228) players. A poor correlation (r = .35) was observed between peak isokinetic hamstring eccentric torque and Nordic hamstring exercise peak force. The strength imbalance between limbs calculated for both test modes was not correlated (r = .037). There is substantial intraindividual variability in all isokinetic test measures, whether separated by 1 or 2 seasons, irrespective of injury. Also, eccentric hamstring strength and limb-to-limb imbalance were poorly correlated between the isokinetic and Nordic hamstring exercise tests. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Electromyographic comparison of concentric and eccentric ...

African Journals Online (AJOL)

The study was conducted to compare the Electromyographic (EMG) activity variation of contractions (concentric and eccentric) during three different abdominal exercises (sit-up) exercises on rectus abdominal (upper and lower rectus). The sit-up exercises were: straight leg sit-up, bent leg sit-up and crunches. The EMG ...

Influence of Wheel Eccentricity on Vertical Vibration of Suspended Monorail Vehicle: Experiment and Simulation

Directory of Open Access Journals (Sweden)

Kaikai Lv

2017-01-01

Full Text Available This paper investigates the influence of wheel eccentricity on vertical vibration of suspended monorail vehicle based on experiment and simulation. Two sets of tests are conducted in the first Chinese suspended monorail, and the tested acceleration is analyzed and exhibited. A multibody dynamic model of the suspended monorail vehicle is established to simulate the vertical vibration of car body excited by wheel eccentricity. The results show that there are three factors which may cause an abnormal vibration considering the track and the vehicle system. The influence of wheel eccentricity on the car body vibration was firstly analyzed. Simulated acceleration of car body has a great accordance with test. The wheel eccentricity could excite the resonance of car body at the speed of 21 km/h, and the vertical acceleration would increase considerably. Decreasing the secondary stiffness can effectively reduce the vertical vibration caused by wheel eccentricity, especially at the resonant speed. In the secondary test, the peak of car body acceleration at speed of 20 km/h is not appearing when only renewing the wheels, and the acceleration is decreasing obviously at the domain frequency. It is further determined that the abnormal vibration is mainly caused by the wheel eccentricity.

Intra-tester Reliability and Construct Validity of a Hip Abductor Eccentric Strength Test.

Science.gov (United States)

Brindle, Richard A; Ebaugh, D David; Milner, Clare E

2017-11-15

Side-lying hip abductor strength tests are commonly used to evaluate muscle strength. In a 'break' test the tester applies sufficient force to lower the limb to the table while the patient resists. The peak force is postulated to occur while the leg is lowering, thus representing the participant's eccentric muscle strength. However, it is unclear whether peak force occurs before or after the leg begins to lower. To determine intra-rater reliability and construct validity of a hip abductor eccentric strength test. Intra-rater reliability and construct validity study. Twenty healthy adults (26 ±6 years; 1.66 ±0.06 m; 62.2 ±8.0 kg) made two visits to the laboratory at least one week apart. During the hip abductor eccentric strength test, a hand-held dynamometer recorded peak force and time to peak force and limb position was recorded via a motion capture system. Intra-rater reliability was determined using intra-class correlation (ICC), standard error of measurement (SEM), and minimal detectable difference (MDD). Construct validity was assessed by determining if peak force occurred after the start of the lowering phase using a one-sample t-test. The hip abductor eccentric strength test had substantial intra-rater reliability (ICC( 3,3 ) = 0.88; 95% confidence interval: 0.65-0.95), SEM of 0.9%BWh, and a MDD of 2.5%BWh. Construct validity was established as peak force occurred 2.1s (±0.6s; range 0.7s to 3.7s) after the start of the lowering phase of the test (p ≤ 0.001). The hip abductor eccentric strength test is a valid and reliable measure of eccentric muscle strength. This test may be used clinically to assess changes in eccentric muscle strength over time.

Benefits of dietary phytochemical supplementation on eccentric exercise-induced muscle damage: Is including antioxidants enough?

Science.gov (United States)

Pereira Panza, Vilma Simões; Diefenthaeler, Fernando; da Silva, Edson Luiz

2015-09-01

The purpose of this review was to critically discuss studies that investigated the effects of supplementation with dietary antioxidant phytochemicals on recovery from eccentric exercise-induced muscle damage. The performance of physical activities that involve unaccustomed eccentric muscle actions-such as lowering a weight or downhill walking-can result in muscle damage, oxidative stress, and inflammation. These events may be accompanied by muscle weakness and delayed-onset muscle soreness. According to the current evidences, supplementation with dietary antioxidant phytochemicals appears to have the potential to attenuate symptoms associated with eccentric exercise-induced muscle damage. However, there are inconsistencies regarding the relationship between muscle damage and blood markers of oxidative stress and inflammation. Furthermore, the effectiveness of strategies appear to depend on a number of aspects inherent to phytochemical compounds as well as its food matrix. Methodological issues also may interfere with the proper interpretation of supplementation effects. Thus, the study may contribute to updating professionals involved in sport nutrition as well as highlighting the interest of scientists in new perspectives that can widen dietary strategies applied to training. Copyright © 2015 Elsevier Inc. All rights reserved.

Force production during squats performed with a rotational resistance device under stable versus unstable conditions.

Science.gov (United States)

Moras, Gerard; Vázquez-Guerrero, Jairo

2015-11-01

[Purpose] Force production during a squat action on a rotational resistance device (RRD) under stable and unstable conditions. [Subjects and Methods] Twenty-one healthy males were asked to perform six sets of six repetitions of squats on an RRD on either stable or unstable surfaces. The stable and unstable sets were performed on different days. Muscular outputs were obtained from a linear encoder and a strain gauge fixed to a vest. [Results] Overall, the results showed no significant differences for any of the dependent variables across exercise modes. Forcemean outputs were higher in the concentric phase than in the eccentric phase for each condition, but there were no differences in velocity, time or displacement. The forcepeak was similar in the eccentric and concentric phases of movement under both stable and unstable conditions. There were no significant differences in forcemean between sets per condition or between conditions. [Conclusion] These results suggest that performing squats with a RRD achieves similar forcemean and forcepeak under stable and unstable conditions. The forcepeak produced is also similar in concentric and eccentric phases.

Optical properties of an elliptic quantum ring: Eccentricity and electric field effects

Science.gov (United States)

Bejan, Doina; Stan, Cristina; Niculescu, Ecaterina C.

2018-04-01

We have theoretically studied the electronic and optical properties of a GaAs/AlGaAs elliptic quantum ring under in-plane electric field. The effects of an eccentric internal barrier -placed along the electric field direction, chosen as x-axis- and incident light polarization are particularly taken into account. The one-electron energy spectrum and wave functions are found using the adiabatic approximation and the finite element method within the effective-mass model. We show that it is possible to repair the structural distortion by applying an appropriate in-plane electric field, and the compensation is almost complete for all electronic states under study. For both concentric and eccentric quantum ring the intraband optical properties are very sensitive to the electric field and probe laser polarization. As expected, in the systems with eccentricity distortions the energy spectrum, as well as the optical response, strongly depends on the direction of the externally applied electric field, an effect that can be used as a signature of ring eccentricity. We demonstrated the possibility of generating second harmonic response at double resonance condition for incident light polarized along the x-axis if the electric field or/and eccentric barrier break the inversion symmetry. Also, strong third harmonic signal can be generated at triple resonance condition for a specific interval of electric field values when using y-polarized light.

The long-term clinical and MRI results following eccentric calf muscle training in chronic Achilles tendinosis

International Nuclear Information System (INIS)

Gaerdin, Anna; Shalabi, Adel; Movin, Tomas; Svensson, Leif

2010-01-01

To evaluate the long-term results following eccentric calf-muscle training in patients with chronic Achilles tendinopathy. A total of 24 patients with chronic Achilles tendinopathy were included in a study evaluating MRI findings and clinical symptoms before and after 3 months of daily eccentric calf-muscle strength training. Median duration of symptoms was 18 months (range 6-120). Four of the patients did not perform the prescribed treatment for different reasons and were followed for 14 months. The resulting 20 treated patients completed 4.2-year (range 29-58 months) follow up. Tendon volume was evaluated by using 3D seed growing technique and signal abnormalities were visually semi-quantitatively graded. Level of pain and performance was categorized using a questionnaire completed by the patient. In the symptomatic treated patients, median intensity level of pain decreased from moderate/severe at time of inclusion to mild at follow up (p 3 (SD 2.0) at time of inclusion and 6.4 cm 3 (SD 2.0) at follow up (p = 0.18). The four symptomatic non-treated tendons did not improve regarding pain, performance, intratendinous signal or tendon volume. We found decreased pain, improved performance and decreased intratendinous signal both compared to index examination and immediately after the 3 months training regimen in a 4.2-year clinical and MRI follow up, in a group of patients treated with heavy loaded eccentric calf-muscle training for chronic Achilles tendinopathy. The improvements were greater at 4.2-year follow up, despite no further active treatment, than immediately after the treatment. This may indicate a good long-term prognosis for Achilles tendinosis patients. (orig.)

Effects of Short-Term Docosahexaenoic Acid Supplementation on Markers of Inflammation after Eccentric Strength Exercise in Women.

Science.gov (United States)

Corder, Katherine E; Newsham, Katherine R; McDaniel, Jennifer L; Ezekiel, Uthayashanker R; Weiss, Edward P

2016-03-01

The omega-3 fatty acid docosahexaenoic acid (DHA) has anti-inflammatory and anti-nociceptive (pain inhibiting) effects. Because strenuous exercise often results in local inflammation and pain, we hypothesized that DHA supplementation attenuates the rise in markers of local muscle inflammation and delayed onset muscle soreness (DOMS) that occur after eccentric strength exercise. Twenty-seven, healthy women (33 ± 2 y, BMI 23.1±1.0 kg·m(-2)) were randomized to receive 9d of 3000 mg/d DHA or placebo in a double-blind fashion. On day 7 of the supplementation period, the participants performed 4 sets of maximal-effort eccentric biceps curl exercise. Before and 48h after the eccentric exercise, markers of inflammation were measured including measures of muscle soreness (10-point visual analog pain scale, VAS), swelling (arm circumference), muscle stiffness (active and passive elbow extension), skin temperature, and salivary C-reactive protein (CRP) concentrations. As expected, muscle soreness and arm circumference increased while active and passive elbow extension decreased. The increase in soreness was 23% less in the DHA group (48h increase in VAS soreness ratings: 4.380.4 vs. 5.600.5, p=0.02). Furthermore, the number of subjects who were able to achieve full active elbow extension 48h after eccentric exercise was greater in the DHA group (71% vs. 15%, p = 0.006), indicating significantly less muscle stiffness. No between-group differences were observed for passive elbow extension (p = 0.78) or arm swelling (p = 0.75). Skin temperature and salivary CRP concentrations did not change from baseline to 48h after exercise in either group. These findings indicate that short-term DHA supplementation reduces exercise-induced muscle soreness and stiffness. Therefore, in addition to other health benefits that n-3 fatty acids have been associated with, DHA supplementation could be beneficial for improving tolerance to new and/or strenuous exercise programs and thereby might

THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF HOT JUPITERS ON HIGHLY ECCENTRIC ORBITS

International Nuclear Information System (INIS)

Kataria, T.; Showman, A. P.; Lewis, N. K.; Fortney, J. J.; Marley, M. S.; Freedman, R. S.

2013-01-01

Of the over 800 exoplanets detected to date, over half are on non-circular orbits, with eccentricities as high as 0.93. Such orbits lead to time-variable stellar heating, which has major implications for the planet's atmospheric dynamical regime. However, little is known about the fundamental dynamical regime of such planetary atmospheres, and how it may influence the observations of these planets. Therefore, we present a systematic study of hot Jupiters on highly eccentric orbits using the SPARC/MITgcm, a model which couples a three-dimensional general circulation model (the MITgcm) with a plane-parallel, two-stream, non-gray radiative transfer model. In our study, we vary the eccentricity and orbit-average stellar flux over a wide range. We demonstrate that the eccentric hot Jupiter regime is qualitatively similar to that of planets on circular orbits; the planets possess a superrotating equatorial jet and exhibit large day-night temperature variations. As in Showman and Polvani, we show that the day-night heating variations induce momentum fluxes equatorward to maintain the superrotating jet throughout its orbit. We find that as the eccentricity and/or stellar flux is increased (corresponding to shorter orbital periods), the superrotating jet strengthens and narrows, due to a smaller Rossby deformation radius. For a select number of model integrations, we generate full-orbit light curves and find that the timing of transit and secondary eclipse viewed from Earth with respect to periapse and apoapse can greatly affect what we see in infrared (IR) light curves; the peak in IR flux can lead or lag secondary eclipse depending on the geometry. For those planets that have large temperature differences from dayside to nightside and rapid rotation rates, we find that the light curves can exhibit 'ringing' as the planet's hottest region rotates in and out of view from Earth. These results can be used to explain future observations of eccentric transiting exoplanets.

Eccentric utilization ratio: effect of sport and phase of training.

Science.gov (United States)

McGuigan, Michael R; Doyle, Timothy L A; Newton, Michael; Edwards, Dylan J; Nimphius, Sophia; Newton, Robert U

2006-11-01

The eccentric utilization ratio (EUR), which is the ratio of countermovement jump (CMJ) to static jump (SJ) performance, has been suggested as a useful indicator of power performance in athletes. The purpose of the study was to compare the EUR of athletes from a variety of different sports and during different phases of training. A total of 142 athletes from rugby union, Australian Rules Football, soccer, softball, and field hockey were tested. Subjects performed both CMJ and SJ on a force plate integrated with a position transducer. The EUR was measured as the ratio of CMJ to SJ for jump height and peak power. The rugby union, Australian Rules Football, and hockey athletes were tested during off-season and preseason to provide EUR data during different phases of training. For men, EUR for soccer, Australian Rules Football, and rugby was greater than softball (effect size range, 0.83-0.92). For women, EUR for soccer was greater than field hockey and softball (0.86- 1.0). There was a significant difference between the jump height and peak power method for the Australian Rules Football, rugby, and field hockey tests conducted preseason (p sports such as soccer, rugby union, and Australian Rules Football appear to have higher EUR values, which reflects the greater reliance on stretch shortening activities in these sports. It does appear that EUR can be used to track changes in training with the values significantly increasing from off-season to preseason. The EUR provides the practitioner with information about the performance of athletes and appears to be sensitive to changes in the type of training being undertaken.

THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. I. MEASURING PHOTOMETRIC ECCENTRICITIES OF INDIVIDUAL TRANSITING PLANETS

International Nuclear Information System (INIS)

Dawson, Rebekah I.; Johnson, John Asher

2012-01-01

Exoplanet orbital eccentricities offer valuable clues about the history of planetary systems. Eccentric, Jupiter-sized planets are particularly interesting: they may link the 'cold' Jupiters beyond the ice line to close-in hot Jupiters, which are unlikely to have formed in situ. To date, eccentricities of individual transiting planets primarily come from radial-velocity measurements. Kepler has discovered hundreds of transiting Jupiters spanning a range of periods, but the faintness of the host stars precludes radial-velocity follow-up of most. Here, we demonstrate a Bayesian method of measuring an individual planet's eccentricity solely from its transit light curve using prior knowledge of its host star's density. We show that eccentric Jupiters are readily identified by their short ingress/egress/total transit durations—part of the 'photoeccentric' light curve signature of a planet's eccentricity—even with long-cadence Kepler photometry and loosely constrained stellar parameters. A Markov Chain Monte Carlo exploration of parameter posteriors naturally marginalizes over the periapse angle and automatically accounts for the transit probability. To demonstrate, we use three published transit light curves of HD 17156 b to measure an eccentricity of e = 0.71 +0.16 –0.09 , in good agreement with the discovery value e = 0.67 ± 0.08 based on 33 radial-velocity measurements. We present two additional tests using Kepler data. In each case, the technique proves to be a viable method of measuring exoplanet eccentricities and their confidence intervals. Finally, we argue that this method is the most efficient, effective means of identifying the extremely eccentric, proto-hot Jupiters predicted by Socrates et al.

Can Eccentric Debris Disks Be Long-lived? A First Numerical Investigation and Application to Zeta(exp 2) Reticuli

Science.gov (United States)

Faramaz, V.; Beust, H.; Thebault, P.; Augereau, J.-C.; Bonsor, A.; delBurgo, C.; Ertel, S.; Marshall, J. P.; Milli, J.; Montesinos, B.;

Short gamma-ray bursts and gravitational-wave observations from eccentric compact binaries

Science.gov (United States)

Tan, Wei-Wei; Fan, Xi-Long; Wang, F. Y.

2018-03-01

Mergers of compact binaries, such as binary neutron stars (BNSs), neutron star-black hole binaries (NSBHs) and binary black holes (BBHs), are expected to be the best candidates for sources of gravitational waves (GWs) and the leading theoretical models for short gamma-ray bursts (SGRBs). Based on observations of SGRBs, we can derive the merger rates of these compact binaries and study stochastic GW backgrounds (SGWBs) or the co-detection rates of GWs associated with SGRBs (GW-SGRBs). Before that, however, the most important thing is to derive the GW spectrum from a single GW source. Usually, a GW spectrum from a circular-orbit binary is assumed. However, observations of the large spatial offsets of SGRBs from their host galaxies imply that SGRB progenitors may be formed by dynamical processes and will merge with residual eccentricities (er). The orbital eccentricity has an important effect on GW spectra and therefore on the SGWB and GW-SGRB co-detection rate. Our results show that the power spectra of SGWBs from eccentric compact binaries are greatly suppressed at low frequencies (e.g. f ≲ 1 Hz). In particular, SGWBs from binaries with high residual eccentricities (e.g. er ≳ 0.1 for BNSs) will be hard to detect (above the detection frequency of ˜ 100 Hz). Regarding the co-detection rates of GW-SGRB events, they could be ˜1.4 times higher than the circular case within some particular ranges of er (e.g. 0.01 ≲ er ≲ 0.1 for BBHs), but greatly reduced for high residual eccentricities (e.g. er > 0.1 for BNSs). In general, BBH progenitors produce 200 and 10 times higher GW-SGRB events than BNS and NSBH progenitors, respectively. Therefore, binaries with low residual eccentricities (e.g. 0.001 ≲ er ≲ 0.1) and high total masses will be easier to detect by Advanced LIGO (aLIGO). However, only a small fraction of BBHs can be SGRB progenitors (if they can produce SGRBs), because the predicted GW-SGRB event rate (60˜100 per year) is too high compared with recent

Including the Copenhagen Adduction Exercise in the FIFA 11+ Provides Missing Eccentric Hip Adduction Strength Effect in Male Soccer Players: A Randomized Controlled Trial.

Science.gov (United States)

Harøy, Joar; Thorborg, Kristian; Serner, Andreas; Bjørkheim, André; Rolstad, Linn E; Hölmich, Per; Bahr, Roald; Andersen, Thor Einar

2017-11-01

The FIFA 11+ was developed as a complete warm-up program to prevent injuries in soccer players. Although reduced hip adduction strength is associated with groin injuries, none of the exercises included in the FIFA 11+ seem to specifically target hip adduction strength. To investigate the effect on eccentric hip adduction strength of the FIFA 11+ warm-up program with or without the Copenhagen adduction exercise. Randomized controlled trial; Level of evidence, 1. We recruited 45 eligible players from 2 U19 elite male soccer teams. Players were randomized into 2 groups; 1 group carried out the standard FIFA 11+ program, while the other carried out the FIFA 11+ but replaced the Nordic hamstring exercise with the Copenhagen adduction exercise. Both groups performed the intervention 3 times weekly for 8 weeks. Players completed eccentric strength and sprint testing before and after the intervention. Per-protocol analyses were performed, and 12 players were excluded due to low compliance (<67% of sessions completed). The main outcome was eccentric hip adduction strength (N·m/kg). Between-group analyses revealed a significantly greater increase in eccentric hip adduction strength of 0.29 Nm/kg (8.9%; P = .01) in favor of the group performing the Copenhagen adduction exercise, whereas no within-group change was noted in the group that used the standard FIFA 11+ program (-0.02 N·m/kg [-0.7%]; P = .69). Including the Copenhagen adduction exercise in the FIFA 11+ program increases eccentric hip adduction strength, while the standard FIFA 11+ program does not. Registration: Registration: ISRCTN13731446 (International Standard Randomised Controlled Trial Number registry).

The Effect of the Rotor Static Eccentricity on the Electro-Mechanical Coupled Characteristics of the Motorized Spindle

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Wu Zaixin

2016-01-01

Full Text Available High-speed motorized spindle is a multi-variable, non-linear and strong coupling system. The rotor static eccentricity is inevitable because of machining or assembling error. The rotor static eccentricities have an important effect on the electromechanical coupled characteristics of the motorized spindle. In this paper, the electromechanical coupled mathematical model of the motorized spindle was set up. The mathematical model includes mechanical and electrical equation. The mechanical and electrical equation is built up by the variational principle. Furthermore, the inductance parameters without the rotor static eccentricity and the inductance parameters with rotor static eccentricity have been calculated by the winding function method and the high speed motorized spindle was simulated. The result show that the rotor static eccentricity can delay the starting process of the motorized spindle, and at steady state, the rotor circuit currents are still large because of the rotor static eccentricity.

An analysis of the expected eccentricity perturbations for the second Radio Astronomy Explorer (RAE B)

Science.gov (United States)

Murphy, J. P.

1972-01-01

Analytical prediction of expected eccentricity perturbations for the RAE 2 lunar orbit shows that the eccentricity will grow linearly in time. Parametric inclination studies and analysis of perturbation equations establish a critical retrograde inclination of 116.565 at which the positive perturbation slope vanishes for a circular orbit about 1100 m above the lunar surface with an eccentricity constraint of less than 0.005 during a period of about one year.

Impact of eccentricity build-up and graveyard disposal Strategies on MEO navigation constellations

Science.gov (United States)

Radtke, Jonas; Domínguez-González, Raúl; Flegel, Sven K.; Sánchez-Ortiz, Noelia; Merz, Klaus

2015-12-01

With currently two constellations being in or close to the build-up phase, in a few years the Medium Earth Orbit (MEO) region will be populated with four complete navigation systems in relatively close orbital altitudes: The American GPS, Russian GLONASS, European Galileo, and Chinese BeiDou. To guarantee an appropriate visibility of constellation satellites from Earth, these constellations rely on certain defined orbits. For this, both the repeat pattern, which is basically defined by the semimajor axis and inclination, as well as the orbital planes, which are defined by the right ascension of ascending node, are determining values. To avoid an overcrowding of the region of interest, the disposal of satellites after their end-of-life is recommended. However, for the MEO region, no internationally agreed mitigation guidelines exist. Because of their distances to Earth, ordinary disposal manoeuvres leading to a direct or delayed re-entry due to atmospheric drag are not feasible: The needed fuel masses for such manoeuvres are by far above the reasonable limits and available fuel budgets. Thus, additional approaches have to be applied. For this, in general two options exist: disposal to graveyard orbits or the disposal to eccentricity build-up orbits. In the study performed, the key criterion for the graveyard strategy is that the disposed spacecraft must keep a safe minimum distance to the altitude of the active constellation on a long-term time scale of up to 200 years. This constraint imposes stringent requirements on the stability of the graveyard orbit. Similar disposals are also performed for high LEO satellites and disposed GEO payloads. The eccentricity build-up strategy on the other hand uses resonant effects between the Earth's geopotential, the Sun and the Moon. Depending on the initial conditions, these can cause a large eccentricity build-up, which finally can lead to a re-entry of the satellite. In this paper, the effects of applying either the first or

ISOMETRIC EXERCISE VERSUS COMBINED CONCENTRIC-ECCENTRIC EXERCISE TRAINING IN PATIENTS WITH OSTEOARTHRITIS KNEE

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Nigombam Amit Kumar

2015-12-01

Full Text Available Background: Osteoarthritis is a slowly evolving articular disease, which appears to originate in the cartilage and affects the underlying bone and soft tissues. OA results in pain and functional disability. The purpose of this study was to determine the effect of isometric exercises and combined concentric-eccentric exercises in reducing pain and functional disability in patients with osteoarthritis of knee. Methods: Forty individuals who were diagnosed as osteoarthritis by qualified orthopaedics and orthopaedic surgeons were chosen and were randomly divided into 2 groups Group A (N=20 and Group B (N=20. Group A was treated with isometric exercises and Group B was treated with combined concentric-eccentric exercises. The intervention lasted eight weeks and the physical activity was carried out for 3 days a week. Both the groups were assessed for pain and functional disability of knee joint by using WOMAC osteoarthritis index and VAS. Results: Between group analysis of pre and post study data reveals that VAS and WOMAC osteoarthritis index revealed significant findings (P=0.00. Group B performs significantly better on both the scales after the treatment. Conclusion: Both the groups showed significant improvement in decreasing pain and functional disability. But mean scores of Group B showed greater improvement in reducing pain and functional disability as compared to Group A in patients with knee osteoarthritis. Thus the results suggest that a combined concentric-eccentric e

Local NSAID infusion inhibits satellite cell proliferation in human skeletal muscle after eccentric exercise

DEFF Research Database (Denmark)

Mikkelsen, U R; Langberg, H; Helmark, I C

2009-01-01

Despite the widespread consumption of nonsteroidal anti-inflammatory drugs (NSAIDs), the influence of these drugs on muscle satellite cells is not fully understood. The aim of the present study was to investigate the effect of a local NSAID infusion on satellite cells after unaccustomed eccentric...... exercise in vivo in human skeletal muscle. Eight young healthy males performed 200 maximal eccentric contractions with each leg. An NSAID was infused via a microdialysis catheter into the vastus lateralis muscle of one leg (NSAID leg) before, during, and for 4.5 h after exercise, with the other leg working...... cells (CD68(+) or CD16(+) cells) was not significantly increased in either of the legs 8 days after exercise and was unaffected by the NSAID. The main finding in the present study was that the NSAID infusion for 7.5 h during the exercise day suppressed the exercise-induced increase in the number...

Temporalis muscle hypertrophy and reduced skull eccentricity in Duchenne muscular dystrophy.

Science.gov (United States)

Straathof, C S M; Doorenweerd, N; Wokke, B H A; Dumas, E M; van den Bergen, J C; van Buchem, M A; Hendriksen, J G M; Verschuuren, J J G M; Kan, H E

2014-10-01

Muscle hypertrophy and muscle weakness are well known in Duchenne muscular dystrophy. Decreased muscle force can have secondary effects on skeletal growth and development such as facial and dental morphology changes. In this study, we quantified temporal muscle thickness, circumference, and eccentricity of the skull and the head on T1-weighted magnetic resonance imaging (MRI) scans of the head of 15 Duchenne muscular dystrophy patients and 15 controls. Average temporal muscle thickness was significantly increased in patients (12.9 ± 5.2 mm) compared to controls (6.8 ± 1.4 mm) (P muscle thickness and skull eccentricity were significantly negatively correlated in patients, and positively in controls. Hypertrophy of the temporal muscles and changes in skull eccentricity appear to occur early in the course of Duchenne muscular dystrophy. Further studies in younger patients are needed to confirm a causal relationship. © The Author(s) 2014.

Metabolic and anti-inflammatory benefits of eccentric endurance exercise - a pilot study.

Science.gov (United States)

Drexel, H; Saely, C H; Langer, P; Loruenser, G; Marte, T; Risch, L; Hoefle, G; Aczel, S

2008-04-01

Eccentric endurance exercise (e.g. hiking downwards) is less strenuous than concentric exercise (e.g. hiking upwards) but its potential to reduce cardiovascular risk is unknown. We randomly allocated 45 healthy sedentary individuals (16 men and 29 women, mean age 48 years) to one of two groups, one beginning with two months of hiking upwards, the other with two months of hiking downwards the same route, with a crossover for a further two months. For the opposite way, a cable car was used where compliance was recorded electronically. The difference in altitude was 540 metres; the distance was covered three to five times a week. Fasting and postprandial metabolic profiles were obtained at baseline and after the two month periods of eccentric and concentric exercise, respectively. Forty-two of the 45 participants completed the study; the compliance rate was therefore 93%. Compared with baseline, eccentric exercise lowered total cholesterol (by 4.1%; P = 0.026), low-density lipoprotein (LDL) cholesterol (by 8.4%, P = 0.001), Apolipoprotein B/Apolipoprotein A1 ratio (by 10.9%, P < 0.001), homeostasis model assessment of insulin resistance scores (by 26.2%, P = 0.017) and C-reactive protein (by 30.0%; P = 0.007); the magnitude of these changes was comparable to that of concentric exercise. Eccentric exercise improved glucose tolerance (by 6.2%, P = 0.023), whereas concentric exercise improved triglyceride tolerance (by 14.9%, P = 0.022). Eccentric endurance exercise is a promising new exercise modality with favourable metabolic and anti-inflammatory effects and is well applicable to sedentary individuals.

Experimental Investigations on Axially and Eccentrically Loaded Masonry Walls

Science.gov (United States)

Keshava, Mangala; Raghunath, Seshagiri Rao

2017-12-01

In India, un-reinforced masonry walls are often used as main structural components in load bearing structures. Indian code on masonry accounts the reduction in strength of walls by using stress reduction factors in its design philosophy. This code was introduced in 1987 and reaffirmed in 1995. The present study investigates the use of these factors for south Indian masonry. Also, with the gaining popularity in block work construction, the aim of this study was to find out the suitability of these factors given in the Indian code to block work masonry. Normally, the load carrying capacity of masonry walls can be assessed in three ways, namely, (1) tests on masonry constituents, (2) tests on masonry prisms and (3) tests on full-scale wall specimens. Tests on bricks/blocks, cement-sand mortar, brick/block masonry prisms and 14 full-scale brick/block masonry walls formed the experimental investigation. The behavior of the walls was investigated under varying slenderness and eccentricity ratios. Hollow concrete blocks normally used as in-fill masonry can be considered as load bearing elements as its load carrying capacity was found to be high when compared to conventional brick masonry. Higher slenderness and eccentricity ratios drastically reduced the strength capacity of south Indian brick masonry walls. The reduction in strength due to slenderness and eccentricity is presented in the form of stress reduction factors in the Indian code. These factors obtained through experiments on eccentrically loaded brick masonry walls was lower while that of brick/block masonry under axial loads was higher than the values indicated in the Indian code. Also the reduction in strength is different for brick and block work masonry thus indicating the need for separate stress reduction factors for these two masonry materials.

Planet-induced Stellar Pulsations in HAT-P-2's Eccentric System

International Nuclear Information System (INIS)

Wit, Julien de; Lewis, Nikole K.; Knutson, Heather A.; Batygin, Konstantin; Fuller, Jim; Antoci, Victoria; Fulton, Benjamin J.; Laughlin, Gregory; Deming, Drake; Shporer, Avi; Cowan, Nicolas B.; Agol, Eric; Burrows, Adam S.; Fortney, Jonathan J.; Langton, Jonathan; Showman, Adam P.

2017-01-01

Extrasolar planets on eccentric short-period orbits provide a laboratory in which to study radiative and tidal interactions between a planet and its host star under extreme forcing conditions. Studying such systems probes how the planet’s atmosphere redistributes the time-varying heat flux from its host and how the host star responds to transient tidal distortion. Here, we report the insights into the planet–star interactions in HAT-P-2's eccentric planetary system gained from the analysis of ∼350 hr of 4.5 μ m observations with the Spitzer Space Telescope . The observations show no sign of orbit-to-orbit variability nor of orbital evolution of the eccentric planetary companion, HAT-P-2 b. The extensive coverage allows us to better differentiate instrumental systematics from the transient heating of HAT-P-2 b’s 4.5 μ m photosphere and yields the detection of stellar pulsations with an amplitude of approximately 40 ppm. These pulsation modes correspond to exact harmonics of the planet’s orbital frequency, indicative of a tidal origin. Transient tidal effects can excite pulsation modes in the envelope of a star, but, to date, such pulsations had only been detected in highly eccentric stellar binaries. Current stellar models are unable to reproduce HAT-P-2's pulsations, suggesting that our understanding of the interactions at play in this system is incomplete.

Profile of isokinetic eccentric-to-concentric strength ratios of shoulder rotator muscles in elite female team handball players.

Science.gov (United States)

Andrade, Marilia Dos Santos; Fleury, Anna Maria; de Lira, Claudio Andre Barbosia; Dubas, Joao Paulo; da Silva, Antonio Carlos

2010-05-01

The purpose of this study was to establish the isokinetic profile of shoulder rotator muscles strength in female handball players. Twenty-seven handball players performed concentric and eccentric strength tests of both dominant and non-dominant upper limbs on an isokinetic dynamometer. Internal and external rotator muscles peak torque was assessed at 1.05, 3.14, and 5.23 rad . s(-1) in concentric mode and at 3.14 and 5.23 rad . s(-1) in eccentric mode. Concentric balance ratio and functional ratio were obtained. Bi-lateral deficiency was compared. Concentric strength for internal and external rotation was significantly greater for the dominant than for the non-dominant limb for all speeds (P muscles were stronger in the dominant than the non-dominant limb (P stronger than the non-dominant side, balance concentric ratios remained the same, with only the functional strength ratio different at 5.23 rad . s(-1). Our results suggest that concentric strength exercises be used for internal and external rotators on the non-dominant side, and functional exercise that improves eccentric rotation strength for prevention programmes.

Effect of eccentric exercise on the healing process of injured patellar tendon in rats.

Science.gov (United States)

Nakamura, Kenichi; Kitaoka, Katsuhiko; Tomita, Katsuro

2008-07-01

Earlier studies have reported positive results from eccentric training in patients with tendon disorders. The reasons for the beneficial clinical effects of eccentric training are not known. Vascularization followed by regression of the vasculature enhances the healing response of injured tendons. Eccentric exercise induces a more beneficial healing response than concentric exercise. Sixty rats with patellar tendon injuries were divided into three groups: nonexercise controls (group N; n = 20); concentric exercise group (group C; n = 20); eccentric exercise group (group E; n = 20). Each rat was taught to run uphill or downhill for 14 days. Patellar tendons were removed 1, 4, 7, 10, and 14 days following injury. Vascular endothelial growth factor (VEGF), angiopoietin-1, and angiopoietin-2 were measured by reverse transcription polymerase chain reaction. In group C, VEGF mRNA was increased 1 and 4 days following injury but was decreased on days 7, 10, and 14. In group E, VEGF mRNA was elevated only on day 1. In group N, VEGF mRNA remained at a low level throughout all 14 days. The angiopoietin-2/angiopoietin-1 ratio was higher for group C than for group E. In the presence of VEGF, angiopoietin-1 promotes vessel stability, whereas angiopoietin-2 has the opposite effect. Eccentric exercise contributes to stabilized angiogenesis during the early phase of tendon injury. Conversely, concentric exercise, which induces destabilized angiogenesis, leads to a delayed healing response. Initiation of eccentric exercise immediately after tendon injury may help improve healing by reducing vascularity.

Histomorphometric analysis of the Achilles tendon of Wistar rats treated with laser therapy and eccentric exercise

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Maria V. de Souza

2015-12-01

lowest amount (p=0.0000 of fibroblasts, according to the morphometric analysis. However, histological evaluation showed a significant group x time interaction (p=0.0024. Greater amounts of fibroblasts were observed in groups E, L and LE on the 7th, 14th and 21st days, respectively. The animals that received laser therapy and were exercised showed a greater (p=0.0000 amount of collagen fibers over time. Laser therapy at a dose of 3J and at a wavelength of 904nm, starting 24h after surgical induction of tendinopathy in Wistar rats, is suitable for angiogenesis and prevention of tendon thickening, which can be associated with the intensity of inflammatory process. When associated with eccentric exercise, the therapy has the advantage of increasing the amount of collagen fibers, reducing fibrinous adhesions and inflammatory infiltrate, despite prolonging angiogenesis. Therefore, eccentric exercise performed concomitantly with laser therapy improves the histological properties of the injured tendon.

eLISA eccentricity measurements as tracers of binary black hole formation

OpenAIRE

Nishizawa, Atsushi; Berti, Emanuele; Klein, Antoine; Sesana, Alberto

2016-01-01

Up to hundreds of black hole binaries individually resolvable by eLISA will coalesce in the Advanced LIGO/Virgo band within ten years, allowing for multi-band gravitational wave observations. Binaries formed via dynamical interactions in dense star clusters are expected to have eccentricities $e_0\\sim 10^{-3}$-$10^{-1}$ at the frequencies $f_0=10^{-2}$ Hz where eLISA is most sensitive, while binaries formed in the field should have negligible eccentricity in both frequency bands. We estimate ...

The gravitational-wave memory from eccentric binaries

International Nuclear Information System (INIS)

Favata, Marc

2011-01-01

The nonlinear gravitational-wave memory causes a time-varying but nonoscillatory correction to the gravitational-wave polarizations. It arises from gravitational-waves that are sourced by gravitational-waves. Previous considerations of the nonlinear memory effect have focused on quasicircular binaries. Here I consider the nonlinear memory from Newtonian orbits with arbitrary eccentricity. Expressions for the waveform polarizations and spin-weighted spherical-harmonic modes are derived for elliptic, hyperbolic, parabolic, and radial orbits. In the hyperbolic, parabolic, and radial cases the nonlinear memory provides a 2.5 post-Newtonian (PN) correction to the leading-order waveforms. This is in contrast to the elliptical and quasicircular cases, where the nonlinear memory corrects the waveform at leading (0PN) order. This difference in PN order arises from the fact that the memory builds up over a short ''scattering'' time scale in the hyperbolic case, as opposed to a much longer radiation-reaction time scale in the elliptical case. The nonlinear memory corrections presented here complete our knowledge of the leading-order (Peters-Mathews) waveforms for elliptical orbits. These calculations are also relevant for binaries with quasicircular orbits in the present epoch which had, in the past, large eccentricities. Because the nonlinear memory depends sensitively on the past evolution of a binary, I discuss the effect of this early-time eccentricity on the value of the late-time memory in nearly circularized binaries. I also discuss the observability of large ''memory jumps'' in a binary's past that could arise from its formation in a capture process. Lastly, I provide estimates of the signal-to-noise ratio of the linear and nonlinear memories from hyperbolic and parabolic binaries.

Eccentric-Overload Training in Team-Sport Functional Performance: Constant Bilateral Vertical Versus Variable Unilateral Multidirectional Movements.

Science.gov (United States)

Gonzalo-Skok, Oliver; Tous-Fajardo, Julio; Valero-Campo, Carlos; Berzosa, César; Bataller, Ana Vanessa; Arjol-Serrano, José Luis; Moras, Gerard; Mendez-Villanueva, Alberto

2017-08-01

To analyze the effects of 2 different eccentric-overload training (EOT) programs, using a rotational conical pulley, on functional performance in team-sport players. A traditional movement paradigm (ie, squat) including several sets of 1 bilateral and vertical movement was compared with a novel paradigm including a different exercise in each set of unilateral and multi-directional movements. Forty-eight amateur or semiprofessional team-sport players were randomly assigned to an EOT program including either the same bilateral vertical (CBV, n = 24) movement (squat) or different unilateral multidirectional (VUMD, n = 24) movements. Training programs consisted of 6 sets of 1 exercise (CBV) or 1 set of 6 exercises (VUMD) × 6-10 repetitions with 3 min of passive recovery between sets and exercises, biweekly for 8 wk. Functional-performance assessment included several change-of-direction (COD) tests, a 25-m linear-sprint test, unilateral multidirectional jumping tests (ie, lateral, horizontal, and vertical), and a bilateral vertical-jump test. Within-group analysis showed substantial improvements in all tests in both groups, with VUMD showing more robust adaptations in pooled COD tests and lateral/horizontal jumping, whereas the opposite occurred in CBV respecting linear sprinting and vertical jumping. Between-groups analyses showed substantially better results in lateral jumps (ES = 0.21), left-leg horizontal jump (ES = 0.35), and 10-m COD with right leg (ES = 0.42) in VUMD than in CBV. In contrast, left-leg countermovement jump (ES = 0.26) was possibly better in CBV than in VUMD. Eight weeks of EOT induced substantial improvements in functional-performance tests, although the force-vector application may play a key role to develop different and specific functional adaptations.

Functional changes at the preferred retinal locus in subjects with bilateral central vision loss.

Science.gov (United States)

Krishnan, Arun Kumar; Bedell, Harold E

2018-01-01

Subjects with bilateral central vision loss (CVL) use a retinal region called the preferred retinal locus (PRL) for performing various visual tasks. We probed the fixation PRL in individuals with bilateral macular disease, including age-related macular degeneration (AMD) and Stargardt disease (STGD), for localized sensitivity deficits. Three letter words at the critical print size were presented in the NIDEK MP-1 microperimeter to determine the fixation PRL and its radial retinal eccentricity from the residual fovea in 29 subjects with bilateral CVL. Fixation stability was defined as the median bivariate contour ellipse area (BCEA) from 3 fixation assessments. A standard 10-2 grid (68 locations, 2° apart) was used to determine central retinal sensitivity for Goldmann size II test spots. Baseline and follow-up supra-threshold screening of the fixation PRL for localized sensitivity deficits was performed using high density (0.2° or 0.3° apart) 0 dB Goldmann size II test spots. Custom MATLAB code and a dual bootstrapping algorithm were used to register test-spot locations from the baseline and follow-up tests. Locations where the 0 dB test spots were not seen on either test were labeled as micro-scotomas (MSs). Median BCEA correlated poorly with the radial eccentricity of the fixation PRL. Mean (±SD) sensitivity around the PRL from 10-2 testing was 4.93 ± 4.73 dB. The average percentage of MSs was similar for patients with AMD (25.4%), STGD (20.3%), and other etiologies of CVL (27.1%). The fixation PRL in subjects with bilateral CVL frequently includes local regions of sensitivity loss.

Eccentric superconducting rf cavity separator structure

International Nuclear Information System (INIS)

Aggus, J.R.; Giordano, S.T.; Halama, H.J.

1976-01-01

An accelerator apparatus is described having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects

Increased residual force enhancement in older adults is associated with a maintenance of eccentric strength.

Directory of Open Access Journals (Sweden)

Geoffrey A Power

Full Text Available Despite an age-related loss of voluntary isometric and concentric strength, muscle strength is well maintained during lengthening muscle actions (i.e., eccentric strength in old age. Additionally, in younger adults during lengthening of an activated skeletal muscle, the force level observed following the stretch is greater than the isometric force at the same muscle length. This feature is termed residual force enhancement (RFE and is believed to be a combination of active and passive components of the contractile apparatus. The purpose of this study was to provide an initial assessment of RFE in older adults and utilize aging as a muscle model to explore RFE in a system in which isometric force production is compromised, but structural mechanisms of eccentric strength are well-maintained. Therefore, we hypothesised that older adults will experience greater RFE compared with young adults. Following a reference maximal voluntary isometric contraction (MVC of the dorsiflexors in 10 young (26.1 ± 2.7 y and 10 old (76.0 ± 6.5 y men, an active stretch was performed at 15°/s over a 30° ankle joint excursion ending at the same muscle length as the reference MVCs (40° of plantar flexion. Any additional torque compared with the reference MVC therefore represented RFE. In older men RFE was ~2.5 times greater compared to young. The passive component of force enhancement contributed ~37% and ~20% to total force enhancement, in old and young respectively. The positive association (R(2 = 0.57 between maintained eccentric strength in old age and RFE indicates age-related mechanisms responsible for the maintenance of eccentric strength likely contributed to the observed elevated RFE. Additionally, as indicated by the greater passive force enhancement, these mechanisms may be related to increased muscle series elastic stiffness in old age.

MOCCA-SURVEY Database. I. Eccentric Black Hole Mergers during Binary–Single Interactions in Globular Clusters

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Samsing, Johan; Askar, Abbas; Giersz, Mirek

2018-03-01

We estimate the population of eccentric gravitational wave (GW) binary black hole (BBH) mergers forming during binary–single interactions in globular clusters (GCs), using ∼800 GC models that were evolved using the MOCCA code for star cluster simulations as part of the MOCCA-Survey Database I project. By re-simulating BH binary–single interactions extracted from this set of GC models using an N-body code that includes GW emission at the 2.5 post-Newtonian level, we find that ∼10% of all the BBHs assembled in our GC models that merge at present time form during chaotic binary–single interactions, and that about half of this sample have an eccentricity >0.1 at 10 Hz. We explicitly show that this derived rate of eccentric mergers is ∼100 times higher than one would find with a purely Newtonian N-body code. Furthermore, we demonstrate that the eccentric fraction can be accurately estimated using a simple analytical formalism when the interacting BHs are of similar mass, a result that serves as the first successful analytical description of eccentric GW mergers forming during three-body interactions in realistic GCs.

Intrarater Reliability of Muscle Strength and Hamstring to Quadriceps Strength Imbalance Ratios During Concentric, Isometric, and Eccentric Maximal Voluntary Contractions Using the Isoforce Dynamometer.

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Mau-Moeller, Anett; Gube, Martin; Felser, Sabine; Feldhege, Frank; Weippert, Matthias; Husmann, Florian; Tischer, Thomas; Bader, Rainer; Bruhn, Sven; Behrens, Martin

2017-08-17

To determine intrasession and intersession reliability of strength measurements and hamstrings to quadriceps strength imbalance ratios (H/Q ratios) using the new isoforce dynamometer. Repeated measures. Exercise science laboratory. Thirty healthy subjects (15 females, 15 males, 27.8 years). Coefficient of variation (CV) and intraclass correlation coefficients (ICC) were calculated for (1) strength parameters, that is peak torque, mean work, and mean power for concentric and eccentric maximal voluntary contractions; isometric maximal voluntary torque (IMVT); rate of torque development (RTD), and (2) H/Q ratios, that is conventional concentric, eccentric, and isometric H/Q ratios (Hcon/Qcon at 60 deg/s, 120 deg/s, and 180 deg/s, Hecc/Qecc at -60 deg/s and Hiso/Qiso) and functional eccentric antagonist to concentric agonist H/Q ratios (Hecc/Qcon and Hcon/Qecc). High reliability: CV 0.90; moderate reliability: CV between 10% and 20%, ICC between 0.80 and 0.90; low reliability: CV >20%, ICC Strength parameters: (a) high intrasession reliability for concentric, eccentric, and isometric measurements, (b) moderate-to-high intersession reliability for concentric and eccentric measurements and IMVT, and (c) moderate-to-high intrasession reliability but low intersession reliability for RTD. (2) H/Q ratios: (a) moderate-to-high intrasession reliability for conventional ratios, (b) high intrasession reliability for functional ratios, (c) higher intersession reliability for Hcon/Qcon and Hiso/Qiso (moderate to high) than Hecc/Qecc (low to moderate), and (d) higher intersession reliability for conventional H/Q ratios (low to high) than functional H/Q ratios (low to moderate). The results have confirmed the reliability of strength parameters and the most frequently used H/Q ratios.

Eccentric Mounting and Adjustment System for Belt Driven Devices

National Research Council Canada - National Science Library

Hansen, David N

2008-01-01

.... The system includes a housing fixed to the engine, a socket rotatable in pawl-and-ratchet fashion within the housing, and a socket aperture eccentrically disposed relative to the socket's axis...

Frequency modulation reveals the phasing of orbital eccentricity during Cretaceous Oceanic Anoxic Event II and the Eocene hyperthermals

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Laurin, Jiří; Meyers, Stephen R.; Galeotti, Simone; Lanci, Luca

2016-05-01

Major advances in our understanding of paleoclimate change derive from a precise reconstruction of the periods, amplitudes and phases of the 'Milankovitch cycles' of precession, obliquity and eccentricity. While numerous quantitative approaches exist for the identification of these astronomical cycles in stratigraphic data, limitations in radioisotopic dating, and instability of the theoretical astronomical solutions beyond ∼50 Myr ago, can challenge identification of the phase relationships needed to constrain climate response and anchor floating astrochronologies. Here we demonstrate that interference patterns accompanying frequency modulation (FM) of short eccentricity provide a robust basis for identifying the phase of long eccentricity forcing in stratigraphic data. One- and two-dimensional models of sedimentary distortion of the astronomical signal are used to evaluate the veracity of the FM method, and indicate that pristine eccentricity FM can be readily distinguished in paleo-records. Apart from paleoclimatic implications, the FM approach provides a quantitative technique for testing and calibrating theoretical astronomical solutions, and for refining chronologies for the deep past. We present two case studies that use the FM approach to evaluate major carbon-cycle perturbations of the Eocene and Late Cretaceous. Interference patterns in the short-eccentricity band reveal that Eocene hyperthermals ETM2 ('Elmo'), H2, I1 and ETM3 (X; ∼52-54 Myr ago) were associated with maxima in the 405-kyr cycle of orbital eccentricity. The same eccentricity configuration favored regional anoxic episodes in the Mediterranean during the Middle and Late Cenomanian (∼94.5-97 Myr ago). The initial phase of the global Oceanic Anoxic Event II (OAE II; ∼93.9-94.5 Myr ago) coincides with maximum and falling 405-kyr eccentricity, and the recovery phase occurs during minimum and rising 405-kyr eccentricity. On a Myr scale, the event overlaps with a node in eccentricity

Determination of concentric and eccentric peak moment values for trunk flexion and extension in sedentary asymptomatic individuals by isokinetic dynamometry: a pilot study

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Rafaella Stradiotto Bernardelli

2017-11-01

Full Text Available The spine has a direct influence on postural alignment and movement of the whole body. Lumbar muscles constitute a critical element in trunk performance while weakness of these muscles has been associated with low back pain. Hence, strength profiling of trunk muscles is clinically significant. The objective of this research was to determine, by means of isokinetic dynamometry, peak moment (PM values during isokinetic concentric and eccentric efforts of trunk flexion and extension in sedentary asymptomatic individuals. The sample consisted of 100 asymptomatic sedentary volunteers, fifty from each sex, aging 22.2 ± 3.3 years old. The sample underwent concentric and eccentric isokinetic assessment of the trunk flexor and extensor muscles at an angular velocity of 60 degrees/sec for each mode of contraction. The mean concentric PM for trunk flexion and extension were 139.5 and 166.6 Nm, respectively, while the respective values for the eccentric efforts were 188.8 and 221.2 Nm. The PM flexion/extension ratio was 0.87 and 0.89 for the concentric and eccentric efforts, respectively. These values of concentric and eccentric PM and PM ratio will serve as comparison parameters for future research, as well as for the assessment of symptomatic patients, and to help in the creation of the trunk muscle rebalance protocols.

Evaluation of a subject-specific, torque-driven computer simulation model of one-handed tennis backhand groundstrokes.

Science.gov (United States)

Kentel, Behzat B; King, Mark A; Mitchell, Sean R

2011-11-01

A torque-driven, subject-specific 3-D computer simulation model of the impact phase of one-handed tennis backhand strokes was evaluated by comparing performance and simulation results. Backhand strokes of an elite subject were recorded on an artificial tennis court. Over the 50-ms period after impact, good agreement was found with an overall RMS difference of 3.3° between matching simulation and performance in terms of joint and racket angles. Consistent with previous experimental research, the evaluation process showed that grip tightness and ball impact location are important factors that affect postimpact racket and arm kinematics. Associated with these factors, the model can be used for a better understanding of the eccentric contraction of the wrist extensors during one-handed backhand ground strokes, a hypothesized mechanism of tennis elbow.

The effect of orbital eccentricity on polarimetric binary diagnostics

International Nuclear Information System (INIS)

Aspin, C.; Brown, J.C.; Simmons, J.F.L.

1980-01-01

The polarimetric variation from a binary system with an eccentric orbit, thus non-corotating, are calculated and the effect on determining the system parameters is discussed, relative to the circular case. (Auth.)

Haemodynamic study of Flow in concentric and eccentric stenosed carotid Artery

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Khader S. M. Abdul

2018-01-01

Full Text Available Study of flow through arteries is gaining importance in the recent times due to onset of several cardio-vascular diseases like atherosclerosis (block in artery, aneurysms (bulging of artery, hypertension etc. The application of CFD will be useful in demonstrating the underlying mechanism of flow past the diseased arteries. In the present study, initially an approximate eccentric and concentric 50% stenosed carotid model is generated in ANSYS 12.0 based on patient data obtained from ultrasound Doppler scan. Later the percentage of stenosis is increased to 60%, 70%, 80% and 90% in both the cases. A transient analysis has been performed for several pulse cycles in ANSYS FLOTRAN for various percentage cases. The results obtained from ECN and CCN cases are compared to observe the changes in flow behavior in the downstream of stenosis as compared with normal case. The formation of vortices and flow separation zone in downstream in eccentric case is higher than in concentric case. Comparison of results concludes that, with the increase in severity of stenosis, the flow changes abruptly causing an increase in velocity and WSS at throat region. The simulation results obtained agree well with clinically observed data and available literature.

Constraining stellar binary black hole formation scenarios with eLISA eccentricity measurements

OpenAIRE

Nishizawa, Atsushi; Sesana, Alberto; Berti, Emanuele; Klein, Antoine

2016-01-01

A space-based interferometer such as eLISA could observe few to few thousands progenitors of black hole binaries (BHBs) similar to those recently detected by Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral, but some BHBs retain a measurable eccentricity at the low frequencies where eLISA is most sensitive. The eccentricity of a BHB carries precious information about its formation channel: BHBs formed in the field, in globular clusters, or close to a massive black...

ESTRADIOL IN FEMALES MAY NEGATE SKELETAL MUSCLE MYOSTATIN MRNA EXPRESSION AND SERUM MYOSTATIN PROPEPTIDE LEVELS AFTER ECCENTRIC MUSCLE CONTRACTIONS

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Darryn S. Willoughby

2006-12-01

Full Text Available Eccentric contractions produce a significant degree of inflammation and muscle injury that may increase the expression of myostatin. Due to its anti- oxidant and anti-flammatory effects, circulating 17-β estradiol (E2 may attenuate myostatin expression. Eight males and eight females performed 7 sets of 10 reps of eccentric contractions of the knee extensors at 150% 1-RM. Each female performed the eccentric exercise bout on a day that fell within her mid-luteal phase (d 21-23 of her 28-d cycle. Blood and muscle samples were obtained before and 6 and 24 h after exercise, while additional blood samples were obtained at 48 and 72 h after exercise. Serum E2 and myostatin LAP/propeptide (LAP/pro levels were determined with ELISA, and myostatin mRNA expression determined using RT-PCR. Data were analyzed with two-way ANOVA and bivariate correlations (p 0.05. Compared to pre-exercise, males had significant increases (p < 0.05 in LAP/propetide and mRNA of 78% and 28%, respectively, at 24 h post-exercise, whereas females underwent respective decreases of 10% and 21%. E2 and LAP/propeptide were correlated at 6 h (r = -0.804, p = 0.016 and 24 h post- exercise (r = -0.841, p = 0.009 in males, whereas in females E2 levels were correlated to myostatin mRNA at 6 h (r =0.739, p = 0.036 and 24 h (r = 0.813, p = 0.014 post-exercise and LAP/propeptide at 6 h (r = 0.713, p = 0.047 and 24 h (r = 0.735, p = 0.038. In females, myostatin mRNA expression and serum LAP/propeptide levels do not appear to be significantly up-regulated following eccentric exercise, and may be due to higher levels of circulating E2

Eccentric and Isometric Hip Adduction Strength in Male Soccer Players With and Without Adductor-Related Groin Pain

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Thorborg, Kristian; Branci, Sonia; Nielsen, Martin Peter; Tang, Lars; Nielsen, Michael Bachmann; Hölmich, Per

2014-01-01

Background: Adductor-related pain is the most common clinical finding in soccer players with groin pain and can be a long-standing problem affecting physical function and performance. Hip adductor weakness has been suggested to be associated with this clinical entity, although it has never been investigated. Purpose: To investigate whether isometric and eccentric hip strength are decreased in soccer players with adductor-related groin pain compared with asymptomatic soccer controls. The hypothesis was that players with adductor-related groin pain would have lower isometric and eccentric hip adduction strength than players without adductor-related groin pain. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Male elite and subelite players from 40 teams were contacted. In total, 28 soccer players with adductor-related groin pain and 16 soccer players without adductor-related groin pain (asymptomatic controls) were included in the study. In primary analysis, the dominant legs of 21 soccer players with adductor-related groin pain (≥4 weeks duration) were compared with the dominant legs of 16 asymptomatic controls using a cross-sectional design. The mean age of the symptomatic players was 24.5 ± 2.5 years, and the mean age of the asymptomatic controls was 22.9 ± 2.4 years. Isometric hip strength (adduction, abduction, and flexion) and eccentric hip strength (adduction) were assessed with a handheld dynamometer using reliable test procedures and a blinded assessor. Results: Eccentric hip adduction strength was lower in soccer players with adductor-related groin pain in the dominant leg (n = 21) compared with asymptomatic controls (n = 16), namely 2.47 ± 0.49 versus 3.12 ± 0.43 N·m/kg, respectively (P strength differences were observed between symptomatic players and asymptomatic controls for the dominant leg (P = .35-.84). Conclusion: Large eccentric hip adduction strength deficits were found in soccer players with adductor-related groin pain

Aortic stenosis with abnormal eccentric left ventricular remodeling secondary to hypothyroidism in a Bourdeaux Mastiff

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Guilherme Augusto Minozzo

Full Text Available ABSTRACT: This paper describes a case of congenital aortic stenosis with eccentric left ventricular hypertrophy associated with hypothyroidism in a 1-year-old Bourdeaux Mastiff dog. The dog had ascites, apathy, alopecic and erythematous skin lesions in different parts of the body. A two-dimensional echocardiogram revealed aortic valve stenosis, with poststenotic dilation in the ascending aorta. The same exam showed eccentric hypertrophy and dilation of the left ventricle during systole and diastole. Aortic stenosis usually results in concentric left ventricular hypertrophy instead of eccentric hypertrophy; and therefore, this finding was very unusual. Hypothyroidism, which is uncommon in young dogs, may be incriminated as the cause of ventricular dilation, making this report even more interesting. Because hypothyroidism would only result in dilatation, the eccentric hypertrophy was attributed to pressure overload caused by aortic stenosis. Thus, cardiac alterations of this case represent a paradoxical association of both diseases.

Neural and morphological adaptations of vastus lateralis and vastus medialis muscles to isokinetic eccentric training

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Rodrigo de Azevedo Franke

2014-09-01

Full Text Available Vastus lateralis (VL and vastus medialis (VM are frequently targeted in conditioning/rehabilitation programs due to their role in patellar stabilization during knee extension. This study assessed neural and muscular adaptations in these two muscles after an isokinetic eccentric training program. Twenty healthy men underwent a four-week control period followed by a 12-week period of isokinetic eccentric training. Ultrasound evaluations of VL and VM muscle thickness at rest and electromyographic evaluations during maximal isometric tests were used to assess the morphological and neural properties, respectively. No morphological and neural changes were found throughout the control period, whereas both muscles showed significant increases in thickness (VL = 6.9%; p .05 post-training. Isokinetic eccentric training produces neural and greater morphological adaptations in VM compared to VL, which shows that synergistic muscles respond differently to an eccentric isokinetic strength training program

The Effects of Spatial Endogenous Pre-cueing across Eccentricities.

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Feng, Jing; Spence, Ian

2017-01-01

Frequently, we use expectations about likely locations of a target to guide the allocation of our attention. Despite the importance of this attentional process in everyday tasks, examination of pre-cueing effects on attention, particularly endogenous pre-cueing effects, has been relatively little explored outside an eccentricity of 20°. Given the visual field has functional subdivisions that attentional processes can differ significantly among the foveal, perifoveal, and more peripheral areas, how endogenous pre-cues that carry spatial information of targets influence our allocation of attention across a large visual field (especially in the more peripheral areas) remains unclear. We present two experiments examining how the expectation of the location of the target shapes the distribution of attention across eccentricities in the visual field. We measured participants' ability to pick out a target among distractors in the visual field after the presentation of a highly valid cue indicating the size of the area in which the target was likely to occur, or the likely direction of the target (left or right side of the display). Our first experiment showed that participants had a higher target detection rate with faster responses, particularly at eccentricities of 20° and 30°. There was also a marginal advantage of pre-cueing effects when trials of the same size cue were blocked compared to when trials were mixed. Experiment 2 demonstrated a higher target detection rate when the target occurred at the cued direction. This pre-cueing effect was greater at larger eccentricities and with a longer cue-target interval. Our findings on the endogenous pre-cueing effects across a large visual area were summarized using a simple model to assist in conceptualizing the modifications of the distribution of attention over the visual field. We discuss our finding in light of cognitive penetration of perception, and highlight the importance of examining attentional process across

The Effects of Spatial Endogenous Pre-cueing across Eccentricities

Directory of Open Access Journals (Sweden)

Jing Feng

2017-06-01

Full Text Available Frequently, we use expectations about likely locations of a target to guide the allocation of our attention. Despite the importance of this attentional process in everyday tasks, examination of pre-cueing effects on attention, particularly endogenous pre-cueing effects, has been relatively little explored outside an eccentricity of 20°. Given the visual field has functional subdivisions that attentional processes can differ significantly among the foveal, perifoveal, and more peripheral areas, how endogenous pre-cues that carry spatial information of targets influence our allocation of attention across a large visual field (especially in the more peripheral areas remains unclear. We present two experiments examining how the expectation of the location of the target shapes the distribution of attention across eccentricities in the visual field. We measured participants’ ability to pick out a target among distractors in the visual field after the presentation of a highly valid cue indicating the size of the area in which the target was likely to occur, or the likely direction of the target (left or right side of the display. Our first experiment showed that participants had a higher target detection rate with faster responses, particularly at eccentricities of 20° and 30°. There was also a marginal advantage of pre-cueing effects when trials of the same size cue were blocked compared to when trials were mixed. Experiment 2 demonstrated a higher target detection rate when the target occurred at the cued direction. This pre-cueing effect was greater at larger eccentricities and with a longer cue-target interval. Our findings on the endogenous pre-cueing effects across a large visual area were summarized using a simple model to assist in conceptualizing the modifications of the distribution of attention over the visual field. We discuss our finding in light of cognitive penetration of perception, and highlight the importance of examining

Dynamical tides in highly eccentric binaries: chaos, dissipation, and quasi-steady state

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Vick, Michelle; Lai, Dong

2018-05-01

Highly eccentric binary systems appear in many astrophysical contexts, ranging from tidal capture in dense star clusters, precursors of stellar disruption by massive black holes, to high-eccentricity migration of giant planets. In a highly eccentric binary, the tidal potential of one body can excite oscillatory modes in the other during a pericentre passage, resulting in energy exchange between the modes and the binary orbit. These modes exhibit one of three behaviours over multiple passages: low-amplitude oscillations, large-amplitude oscillations corresponding to a resonance between the orbital frequency and the mode frequency, and chaotic growth, with the mode energy reaching a level comparable to the orbital binding energy. We study these phenomena with an iterative map that includes mode dissipation, fully exploring how the mode evolution depends on the orbital and mode properties of the system. The dissipation of mode energy drives the system towards a quasi-steady state, with gradual orbital decay punctuated by resonances. We quantify the quasi-steady state and the long-term evolution of the system. A newly captured star around a black hole can experience significant orbital decay and heating due to the chaotic growth of the mode amplitude and dissipation. A giant planet pushed into a high-eccentricity orbit may experience a similar effect and become a hot or warm Jupiter.

Planet-induced Stellar Pulsations in HAT-P-2's Eccentric System

Energy Technology Data Exchange (ETDEWEB)

Wit, Julien de [Department of Earth, Atmospheric and Planetary Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Lewis, Nikole K. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Knutson, Heather A.; Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Fuller, Jim [TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Antoci, Victoria [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Fulton, Benjamin J. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Laughlin, Gregory [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Deming, Drake [Department of Astronomy, University of Maryland at College Park, College Park, MD 20742 (United States); Shporer, Avi [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91009 (United States); Cowan, Nicolas B. [Department of Physics, Department of Earth and Planetary Sciences, McGill University, 3550 rue University, Montreal, QC H3A 2A7 (Canada); Agol, Eric [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Burrows, Adam S. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Langton, Jonathan [Department of Physics, Principia College, Elsah, IL 62028 (United States); Showman, Adam P. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2017-02-20

Extrasolar planets on eccentric short-period orbits provide a laboratory in which to study radiative and tidal interactions between a planet and its host star under extreme forcing conditions. Studying such systems probes how the planet’s atmosphere redistributes the time-varying heat flux from its host and how the host star responds to transient tidal distortion. Here, we report the insights into the planet–star interactions in HAT-P-2's eccentric planetary system gained from the analysis of ∼350 hr of 4.5 μ m observations with the Spitzer Space Telescope . The observations show no sign of orbit-to-orbit variability nor of orbital evolution of the eccentric planetary companion, HAT-P-2 b. The extensive coverage allows us to better differentiate instrumental systematics from the transient heating of HAT-P-2 b’s 4.5 μ m photosphere and yields the detection of stellar pulsations with an amplitude of approximately 40 ppm. These pulsation modes correspond to exact harmonics of the planet’s orbital frequency, indicative of a tidal origin. Transient tidal effects can excite pulsation modes in the envelope of a star, but, to date, such pulsations had only been detected in highly eccentric stellar binaries. Current stellar models are unable to reproduce HAT-P-2's pulsations, suggesting that our understanding of the interactions at play in this system is incomplete.

Flow of viscoplastic fluids in eccentric annular geometries

DEFF Research Database (Denmark)

Szabo, Peter; Hassager, Ole

1992-01-01

A classification of flowfields for the flow of a Bingham fluid in general eccentric annular geometries is presented. Simple arguments show that a singularity can exist in the stress gradient on boundaries between zones with yielded and un-yielded fluid respectively. A Finite Element code is used...

Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

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Josh L. Secomb, Sophia Nimphius, Oliver R.L. Farley, Lina E. Lundgren, Tai T. Tran, Jeremy M. Sheppard

2015-12-01

Full Text Available The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ and squat jump (SJ, and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23 and female (n = 7 surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP. In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73 were identified between the thickness of the vastus lateralis (VL and lateral gastrocnemius (LG muscles, and VL pennation angle and; peak force (PF in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59 were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59 also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle.

The influence of resistance exercise with emphasis on specific contractions (concentric vs. eccentric on muscle strength and post-exercise autonomic modulation: a randomized clinical trial

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Mariana O. Gois

2014-01-01

Full Text Available Background: Compared to eccentric contractions, concentric contractions result in higher cardiovascular stress. However, we do not know how these two types of contractions influence cardiac autonomic modulation during the post-exercise recovery period. Objective: to compare the effect of resistance training that is performed with concentric vs. eccentric emphasis on muscle strength and on post-exercise recovery which was assessed by examining heart rate variability (HRV, for the knee extensor muscle group in young healthy adults. Methods: For this study, 105 men between 18 and 30 years of age were randomized into 4 groups: concentric control (CONCC, eccentric control (ECCC, concentric training (CONCT and eccentric training (ECCT. The CONCC and ECCC groups underwent one session of resistance exercise (RE using the knee extensor muscle group (3 sets of 1 repetition at 100% of the maximal repetition [1MR] and the CONCT and ECCT groups performed 10 training sessions. The HRV was analyzed at baseline and across four recovery periods (T1, T2, T3 and T4. Results: The ECCT group exhibited increased muscle strength at the end of the study. Regarding cardiac autonomic modulation, the CONCC and ECCC groups exhibited increases in overall variability (SDNN and SD2 at T1 compared to baseline, and the ECCT group demonstrated increases in variables reflecting vagal modulation and the recovery process (RMSSD, SD1 and HF [ms2] at T1, T2 and T4 compared to baseline. Conclusions: Resistance training with emphasis on eccentric contractions promoted strength gain and an increase in cardiac vagal modulation during recovery compared to baseline.

Leucine-Enriched Essential Amino Acids Augment Muscle Glycogen Content in Rats Seven Days after Eccentric Contraction

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Hiroyuki Kato

2017-10-01

Full Text Available Eccentric contractions induce muscle damage, which impairs recovery of glycogen and adenosine tri-phosphate (ATP content over several days. Leucine-enriched essential amino acids (LEAAs enhance the recovery in muscles that are damaged after eccentric contractions. However, the role of LEAAs in this process remains unclear. We evaluated the content in glycogen and high energy phosphates molecules (phosphocreatine (PCr, adenosine di-phosphate (ADP and ATP in rats that were following electrically stimulated eccentric contractions. Muscle glycogen content decreased immediately after the contraction and remained low for the first three days after the stimulation, but increased seven days after the eccentric contraction. LEAAs administration did not change muscle glycogen content during the first three days after the contraction. Interestingly, however, it induced a further increase in muscle glycogen seven days after the stimulation. Contrarily, ATP content decreased immediately after the eccentric contraction, and remained lower for up to seven days after. Additionally, LEAAs administration did not affect the ATP content over the experimental period. Finally, ADP and PCr levels did not significantly change after the contractions or LEAA administration. LEAAs modulate the recovery of glycogen content in muscle after damage-inducing exercise.

Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations

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Martino V. Franchi

2017-07-01

Full Text Available Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively; however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT is assumed to produce greater hypertrophy than concentric resistance training (CON RT. Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood.Thus, the present review aims to, (a critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b clarify the molecular mechanisms that may regulate such adaptations.We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions.

Effectiveness of Shockwave Treatment Combined With Eccentric Training for Patellar Tendinopathy : A Double-Blinded Randomized Study

NARCIS (Netherlands)

Thijs, Karin M; Zwerver, Johannes; Backx, Frank J G; Steeneken, Victor; Rayer, Stephan; Groenenboom, Petra; Moen, Maarten H

OBJECTIVE: To evaluate the effectiveness of a combined treatment of focused shockwave therapy (ESWT) and eccentric training compared with sham-shockwave therapy (placebo) and eccentric training in participants with patellar tendinopathy (PT) after 24 weeks. DESIGN: Randomized controlled trial.

Effectiveness of Shockwave Treatment Combined With Eccentric Training for Patellar Tendinopathy : A Double-Blinded Randomized Study

NARCIS (Netherlands)

Thijs, Karin M.; Zwerver, Johannes; Backx, Frank J. G.; Steeneken, Victor; Rayer, Stephan; Groenenboom, Petra; Moen, Maarten H.

2017-01-01

OBJECTIVE: To evaluate the effectiveness of a combined treatment of focused shockwave therapy (ESWT) and eccentric training compared with sham-shockwave therapy (placebo) and eccentric training in participants with patellar tendinopathy (PT) after 24 weeks. DESIGN: Randomized controlled trial.

Study on the optical properties of the off-axis parabolic collimator with eccentric pupil

Science.gov (United States)

Li, Gang; Gao, Xin; Duan, Jing; Zhang, Henjin

2017-02-01

The off-axis parabolic collimator with eccentric pupil has the advantages of wide spectrum, simple structure, easy assembly and adjustment, high performance price ratio. So, it is widely used for parameters testing and image quality calibration of ground-based and space-based cameras. In addition to the Strehl ratio, resolution, wavefront aberration, modulation transfer function, the general evaluation criteria on the imaging quality of the optical system, the beam parallelism characterize the collimator angle resolving capability and collimation condition of the collimator with the target board, can be measured easily ,quickly and operation process is simple, but the study mainly focus on how to measure it so far. In order to solve Quantitative calculation of this problem, firstly, the discussion of aberration condition of the off- axis parabolic is carried out based on the primary aberration theory. Secondly, analysis on the influencing factor on collimator optical properties is given, including the geometrical aberrations of spherical aberration, coma, astigmatism , the relation between the position of the eccentric pupil and the aberration and optical element surface wavefront aberration, after that, according to the basis of diffraction and wavefront aberration theory, the paper deduced calculation method of the beam parallelism, at last, an example of a 400mm diameter off-axis parabolic collimator with eccentric pupil is given to calculate, the practical results shows that calculation data is well in accordance with actual measurement data and results can meet the demand and has a guiding significance to the actual project manufacture and the theory analysis.

Does Eccentric Exercise Reduce Pain and Improve Strength in Physically Active Adults With Symptomatic Lower Extremity Tendinosis? A Systematic Review

Science.gov (United States)

Wasielewski, Noah J; Kotsko, Kevin M

2007-01-01

Objective: To critically review evidence for the effectiveness of eccentric exercise to treat lower extremity tendinoses. Data Sources: Databases used to locate randomized controlled trials (RCTs) included PubMed (1980–2006), CINAHL (1982–2006), Web of Science (1995–2006), SPORT Discus (1980–2006), Physiotherapy Evidence Database (PEDro), and the Cochrane Collaboration Database. Key words included tendon, tendonitis, tendinosis, tendinopathy, exercise, eccentric, rehabilitation, and therapy. Study Selection: The criteria for trial selection were (1) the literature was written in English, (2) the research design was an RCT, (3) the study participants were adults with a clinical diagnosis of tendinosis, (4) the outcome measures included pain or strength, and (5) eccentric exercise was used to treat lower extremity tendinosis. Data Extraction: Specific data were abstracted from the RCTs, including eccentric exercise protocol, adjunctive treatments, concurrent physical activity, and treatment outcome. Data Synthesis: The calculated post hoc statistical power of the selected studies (n = 11) was low, and the average methodologic score was 5.3/10 based on PEDro criteria. Eccentric exercise was compared with no treatment (n = 1), concentric exercise (n = 5), an alternative eccentric exercise protocol (n = 1), stretching (n = 2), night splinting (n = 1), and physical agents (n = 1). In most trials, tendinosis-related pain was reduced with eccentric exercise over time, but only in 3 studies did eccentric exercise decrease pain relative to the control treatment. Similarly, the RCTs demonstrated that strength-related measures improved over time, but none revealed significant differences relative to the control treatment. Based on the best evidence available, it appears that eccentric exercise may reduce pain and improve strength in lower extremity tendinoses, but whether eccentric exercise is more effective than other forms of therapeutic exercise for the resolution

Gas exchange kinetics following concentric-eccentric isokinetic arm and leg exercise.

Science.gov (United States)

Drescher, U; Mookerjee, S; Steegmanns, A; Knicker, A; Hoffmann, U

2017-06-01

To evaluate the effects of exercise velocity (60, 150, 240deg∙s -1 ) and muscle mass (arm vs leg) on changes in gas exchange and arterio-venous oxygen content difference (avDO 2 ) following high-intensity concentric-eccentric isokinetic exercise. Fourteen subjects (26.9±3.1years) performed a 3×20-repetition isokinetic exercise protocol. Recovery beat-to-beat cardiac output (CO) and breath-by-breath gas exchange were recorded to determine post-exercise half-time (t 1/2 ) for oxygen uptake (V˙O 2 pulm), carbon dioxide output (V˙CO 2 pulm), and ventilation (V˙ E ). Significant differences of the t 1/2 values were identified between 60 and 150deg∙s -1 . Significant differences in the t 1/2 values were observed between V˙O 2 pulm and V˙CO 2 pulm and between V˙CO 2 pulm and V˙ E . The time to attain the first avDO 2 -peak showed significant differences between arm and leg exercise. The present study illustrates, that V˙O 2 pulm kinetics are distorted due to non-linear CO dynamics. Therefore, it has to be taken into account, that V˙O 2 pulm may not be a valuable surrogate for muscular oxygen uptake kinetics in the recovery phases. Copyright © 2017 Elsevier B.V. All rights reserved.

A STRANGE STAR SCENARIO FOR THE FORMATION OF ECCENTRIC MILLISECOND PULSAR/HELIUM WHITE DWARF BINARIES

Energy Technology Data Exchange (ETDEWEB)

Jiang, Long; Li, Xiang-Dong [Department of Astronomy, Nanjing University, Nanjing 210046 (China); Dey, Jishnu; Dey, Mira, E-mail: lixd@nju.edu.cn [Department of Physics, Presidency University, 86/1, College Street, Kolkata 700 073 (India)

2015-07-01

According to the recycling scenario, millisecond pulsars (MSPs) have evolved from low-mass X-ray binaries (LMXBs). Their orbits are expected to be circular due to tidal interactions during binary evolution, as observed in most binary MSPs. There are some peculiar systems that do not fit this picture. Three recent examples are the PSRs J2234+06, J1946+3417, and J1950+2414, all of which are MSPs in eccentric orbits but with mass functions compatible with expected He white dwarf (WD) companions. It has been suggested these MSPs may have formed from delayed accretion-induced collapse of massive WDs, or the eccentricity may be induced by dynamical interaction between the binary and a circumbinary disk. Assuming that the core density of accreting neutron stars (NSs) in LMXBs may reach the density of quark deconfinement, which can lead to phase transition from NSs to strange quark stars, we show that the resultant MSPs are likely to have an eccentric orbit, due to the sudden loss of the gravitational mass of the NS during the transition. The eccentricities can be reproduced with a reasonable estimate of the mass loss. This scenario might also account for the formation of the youngest known X-ray binary Cir X–1, which also possesses a low-field compact star in an eccentric orbit.

Development of a novel cold forging process to manufacture eccentric shafts

Science.gov (United States)

Pasler, Lukas; Liewald, Mathias

2018-05-01

Since the commercial usage of compact combustion engines, eccentric shafts have been used to transform translational into rotational motion. Over the years, several processes to manufacture these eccentric shafts or crankshafts have been developed. Especially for single-cylinder engines manufactured in small quantities, built crankshafts disclose advantages regarding tooling costs and performance. Those manufacturing processes do have one thing in common: They are all executed at elevated temperatures to enable the material to be formed to high forming degree. In this paper, a newly developed cold forging process is presented, which combines lateral extrusion and shifting for manufacturing a crank in one forming operation at room temperature. In comparison to the established upsetting and shifting methods to manufacture such components, the tool cavity or crank web thickness remains constant. Therefore, the developed new process presented in this paper consists of a combination of shifting and extrusion of the billet, which allows pushing material into the forming zone during shifting. In order to reduce the tensile stresses induced by the shifting process, compressive stresses are superimposed. It is expected that the process limits will be expanded regarding the horizontal displacement and form filling. In the following report, the simulation and design of the tooling concept are presented. Experiments were conducted and compared with corresponding simulation results afterwards.

Orbital tidal variability in the eccentric early type binary Iota Orionis

International Nuclear Information System (INIS)

Stevens, I.R.

1988-01-01

Iota Orionis is a bright, highly eccentric, massive early type binary, which has been studied recently in UV wavelengths, for evidence of stellar wind variability caused by tidal interactions between the two stars. No gross variability was found, but small scale perturbations in the UV resonance line profiles were noted. Here, using a radiatively driven stellar wind model for eccentric binaries, the results of numerical modelling of the stellar wind of Iota Orionis are presented. These calculations suggest that increased mass-loss from the primary star will occur close to the periastron passage, but that the enhancements will be short lived, and observed probably as redshifted emission features. (author)

CLIMATE PATTERNS OF HABITABLE EXOPLANETS IN ECCENTRIC ORBITS AROUND M DWARFS

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuwei; Hu, Yongyun [Laboratory for Climate and Ocean-Atmosphere Sciences, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871 China (China); Tian, Feng, E-mail: yyhu@pku.edu.cn [Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084 (China)

2014-08-10

Previous studies show that synchronous rotating habitable exoplanets around M dwarfs should have an ''eyeball'' climate pattern—a limited region of open water on the day side and ice on the rest of the planet. However, exoplanets with nonzero eccentricities could have spin-orbit resonance states different from the synchronous rotation state. Here, we show that a striped-ball climate pattern, with a global belt of open water at low and middle latitudes and ice over both polar regions, should be common on habitable exoplanets in eccentric orbits around M dwarfs. We further show that these different climate patterns can be observed by future exoplanet detection missions.

Extreme secular excitation of eccentricity inside mean motion resonance. Small bodies driven into star-grazing orbits by planetary perturbations

Science.gov (United States)

Pichierri, Gabriele; Morbidelli, Alessandro; Lai, Dong

2017-09-01

Context. It is well known that asteroids and comets fall into the Sun. Metal pollution of white dwarfs and transient spectroscopic signatures of young stars like β-Pic provide growing evidence that extra solar planetesimals can attain extreme orbital eccentricities and fall into their parent stars. Aims: We aim to develop a general, implementable, semi-analytical theory of secular eccentricity excitation of small bodies (planetesimals) in mean motion resonances with an eccentric planet valid for arbitrary values of the eccentricities and including the short-range force due to General Relativity. Methods: Our semi-analytic model for the restricted planar three-body problem does not make use of series expansion and therefore is valid for any eccentricity value and semi-major axis ratio. The model is based on the application of the adiabatic principle, which is valid when the precession period of the longitude of pericentre of the planetesimal is much longer than the libration period in the mean motion resonance. In resonances of order larger than 1 this is true except for vanishingly small eccentricities. We provide prospective users with a Mathematica notebook with implementation of the model allowing direct use. Results: We confirm that the 4:1 mean motion resonance with a moderately eccentric (e' ≲ 0.1) planet is the most powerful one to lift the eccentricity of planetesimals from nearly circular orbits to star-grazing ones. However, if the planet is too eccentric, we find that this resonance is unable to pump the planetesimal's eccentricity to a very high value. The inclusion of the General Relativity effect imposes a condition on the mass of the planet to drive the planetesimals into star-grazing orbits. For a planetesimal at 1 AU around a solar mass star (or white dwarf), we find a threshold planetary mass of about 17 Earth masses. We finally derive an analytical formula for this critical mass. Conclusions: Planetesimals can easily fall into the central star

Predicting BCI subject performance using probabilistic spatio-temporal filters.

Directory of Open Access Journals (Sweden)

Heung-Il Suk

Full Text Available Recently, spatio-temporal filtering to enhance decoding for Brain-Computer-Interfacing (BCI has become increasingly popular. In this work, we discuss a novel, fully Bayesian-and thereby probabilistic-framework, called Bayesian Spatio-Spectral Filter Optimization (BSSFO and apply it to a large data set of 80 non-invasive EEG-based BCI experiments. Across the full frequency range, the BSSFO framework allows to analyze which spatio-spectral parameters are common and which ones differ across the subject population. As expected, large variability of brain rhythms is observed between subjects. We have clustered subjects according to similarities in their corresponding spectral characteristics from the BSSFO model, which is found to reflect their BCI performances well. In BCI, a considerable percentage of subjects is unable to use a BCI for communication, due to their missing ability to modulate their brain rhythms-a phenomenon sometimes denoted as BCI-illiteracy or inability. Predicting individual subjects' performance preceding the actual, time-consuming BCI-experiment enhances the usage of BCIs, e.g., by detecting users with BCI inability. This work additionally contributes by using the novel BSSFO method to predict the BCI-performance using only 2 minutes and 3 channels of resting-state EEG data recorded before the actual BCI-experiment. Specifically, by grouping the individual frequency characteristics we have nicely classified them into the subject 'prototypes' (like μ - or β -rhythm type subjects or users without ability to communicate with a BCI, and then by further building a linear regression model based on the grouping we could predict subjects' performance with the maximum correlation coefficient of 0.581 with the performance later seen in the actual BCI session.

Friction and Wear Reduction of Eccentric Journal Bearing Made of Sn-Based Babbitt for Ore Cone Crusher

OpenAIRE

Amanov, Auezhan; Ahn, Byungmin; Lee, Moon Gu; Jeon, Yongho; Pyun, Young-Sik

2016-01-01

An anti-friction Babbitt alloy-coated bearing made by a casting process is a journal bearing, which is used in an ore cone crusher eccentric. The main purpose of the Babbitt coated eccentric is to provide a low friction to support and guide a rotating shaft. Despite the fact that the Babbitt-coated eccentric offers a low friction coefficient and can be operated without a continuous supply of lubricant, it suffers from mining environments and short service life. In this study, an ultrasonic na...

Experimental study and CFD simulation of rotational eccentric cylinder in a magnetorheological fluid

International Nuclear Information System (INIS)

Omidbeygi, F.; Hashemabadi, S.H.

2012-01-01

In this study, a magnetorheological (MR) fluid is prepared using carbonyl iron filings and low viscosity lubricating oil. The effects of magnetic field and weight percentage of particles on the viscosity of the MR fluid have been measured using a rotational viscometer. The yield stress under an applied magnetic field was also obtained experimentally. In the absence of an applied magnetic field, the MR fluid behaves as a Newtonian fluid. When the magnetic field is applied, the MR fluid behaves like Bingham plastics with a magnetic field dependent yield stress. Afterward, the results compared with those of CFD simulation of two eccentric cylinders in the MR fluid. Results show that the influences of MR effects, caused by the applied magnetic field, on the model characteristics are significant and not negligible. The viscosity is enhanced by increasing of the magnetic field, eccentricity ratio and weight percentage of suspensions. The MR effects and increasing of weight percentage and eccentricity ratio also provide an enhancement in the yield stresses and required total torque for rotation of inner cylinder. Also the simulation results indicate a good representation of the experiment by the model. - Highlights: ► Preparation of a magnetorheological fluid with carbonyl iron particles in lubricating oil. ► Rheological measurement for influence of solid content and magnetic field intensity. ► Simulation of eccentric rotating cylinder in prepared MR fluid with CFD techniques.

Eccentric Knee Flexor Strength and Risk of Hamstring Injuries in Rugby Union: A Prospective Study.

Science.gov (United States)

Bourne, Matthew N; Opar, David A; Williams, Morgan D; Shield, Anthony J

2015-11-01

Hamstring strain injuries (HSIs) represent the most common cause of lost playing time in rugby union. Eccentric knee flexor weakness and between-limb imbalance in eccentric knee flexor strength are associated with a heightened risk of HSIs in other sports; however, these variables have not been explored in rugby union. To determine if lower levels of eccentric knee flexor strength or greater between-limb imbalance in this parameter during the Nordic hamstring exercise are risk factors for HSIs in rugby union. Cohort study; Level of evidence, 2. This prospective study was conducted over the 2014 Super Rugby and Queensland Rugby Union seasons. In total, 178 rugby union players (mean age, 22.6 ± 3.8 years; mean height, 185.0 ± 6.8 cm; mean weight, 96.5 ± 13.1 kg) had their eccentric knee flexor strength assessed using a custom-made device during the preseason. Reports of previous hamstring, quadriceps, groin, calf, and anterior cruciate ligament injuries were also obtained. The main outcome measure was the prospective occurrence of HSIs. Twenty players suffered at least 1 HSI during the study period. Players with a history of HSIs had a 4.1-fold (95% CI, 1.9-8.9; P = .001) greater risk of subsequent HSIs than players without such a history. Between-limb imbalance in eccentric knee flexor strength of ≥15% and ≥20% increased the risk of HSIs by 2.4-fold (95% CI, 1.1-5.5; P = .033) and 3.4-fold (95% CI, 1.5-7.6; P = .003), respectively. Lower eccentric knee flexor strength and other prior injuries were not associated with an increased risk of future HSIs. Multivariate logistic regression revealed that the risk of reinjuries was augmented in players with strength imbalances. Previous HSIs and between-limb imbalance in eccentric knee flexor strength were associated with an increased risk of future HSIs in rugby union. These results support the rationale for reducing imbalance, particularly in players who have suffered a prior HSI, to mitigate the risk of future

A numerical investigation on the eccentricity growth of GNSS disposal orbits

Science.gov (United States)

Alessi, E. M.; Deleflie, F.; Rosengren, A. J.; Rossi, A.; Valsecchi, G. B.; Daquin, J.; Merz, K.

2016-05-01

We present the results of an extensive numerical exploration performed on the eccentricity growth in MEO associated with two possible end-of-life disposal strategies for GNSS satellites. The study calls attention to the existence of values of initial inclination, longitude of ascending node, and argument of perigee that are more advantageous in terms of long-term stability of the orbit. The important role of the initial epoch and a corresponding periodicity are also shown. The present investigation is influential in view of recent analytical and numerical developments on the chaotic nature of the region due to lunisolar perturbations, but also for the upcoming Galileo and BeiDou constellations.

Subjective performance evaluations and reciprocity in principal-agent relations

DEFF Research Database (Denmark)

Sebald, Alexander Christopher; Walzl, Markus

2014-01-01

. In contrast to existing models of reciprocity, we find that agents tend to sanction whenever the feedback of principals is below their subjective self-evaluations even if agents' pay-offs are independent of it. In turn, principals provide more positive feedback (relative to their actual performance assessment......We conduct a laboratory experiment with agents working on, and principals benefiting from, a real effort task in which the agents' performance can only be evaluated subjectively. Principals give subjective performance feedback to agents, and agents have an opportunity to sanction principals...... of the agent) if this does not affect their pay-off....

On the orbital eccentricity of V477 Cygni

International Nuclear Information System (INIS)

Scarfe, C.D.; Barlow, D.J.; Niehaus, R.J.

1976-01-01

The eclipsing binary V477 Cygni (BD+31 0 3932) is a Main-Sequence system with unequal components, a substantial orbital eccentricity and clearly detectable apsidal rotation. Recent photoelectric times of minima support the value e=0.3 obtained by O'Connell (1970). The lower value obtained by Budding (1974) is ruled out. (Auth.)

Effects of combined β-hydroxy-β-methylbutyrate (HMB) and whey protein ingestion on symptoms of eccentric exercise-induced muscle damage.

Science.gov (United States)

Shirato, Minayuki; Tsuchiya, Yosuke; Sato, Teruyuki; Hamano, Saki; Gushiken, Takeshi; Kimura, Naoto; Ochi, Eisuke

2016-01-01

The purpose of this study was to examine the effects of combined β-hydroxy-β-methylbutyrate (HMB) and whey protein ingestion on muscle strength and damage following a single bout of eccentric exercise. Eighteen untrained male subjects were assigned to HMB and Whey protein (HMB + Whey; 3 g/day HMB and 36.6 g/day whey protein, n = 6), HMB (3 g/day, n = 6), or whey protein (36.6 g/day, n = 6) groups. Ingestion commenced 7 days before non-dominant elbow flexor eccentric exercise (30 deg/sec, 6 reps × 7 sets) and continued until 4 days post-exercise. The maximal isometric strength, muscle soreness, plasma creatine kinase (CK), lactate dehydrogenase (LDH) were assessed pre-exercise, and at 1, 2, 3, and 5 days after exercise. The change scores of maximal isometric strength significantly decreased at day 1, 2, and 5 in the whey protein group compared to pre value and that in HMB + Whey protein and HMB groups decreased at day 1 and 5. The muscle soreness significantly increased in the whey and HMB + Whey protein groups at day 3 compared to pre value (p HMB and whey protein does not have a role to inhibit muscle strength loss and soreness, and decrease in muscle damage markers after eccentric exercise in comparison with HMB and whey protein alone.

Equatorial insolation: from precession harmonics to eccentricity frequencies

Directory of Open Access Journals (Sweden)

A. Berger

2006-01-01

Full Text Available Since the paper by Hays et al. (1976, spectral analyses of climate proxy records provide substantial evidence that a fraction of the climatic variance is driven by insolation changes in the frequency ranges of obliquity and precession variations. However, it is the variance components centered near 100 kyr which dominate most Upper Pleistocene climatic records, although the amount of insolation perturbation at the eccentricity driven periods close to 100-kyr (mainly the 95 kyr- and 123 kyr-periods is much too small to cause directly a climate change of ice-age amplitude. Many attempts to find an explanation to this 100-kyr cycle in climatic records have been made over the last decades. Here we show that the double maximum which characterizes the daily irradiation received in tropical latitudes over the course of the year is at the origin in equatorial insolation of not only strong 95 kyr and 123 kyr periods related to eccentricity, but also of a 11-kyr and a 5.5-kyr periods related to precession.

Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization

Science.gov (United States)

Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan EB; Kastner, Sabine; Hasson, Uri

2015-01-01

The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas. DOI: http://dx.doi.org/10.7554/eLife.03952.001 PMID:25695154

Effect of relative pile’s stiffness on lateral pile response under loading of large eccentricity

DEFF Research Database (Denmark)

Zania, Varvara; Hededal, Ole; Klinkvort, R.T.

2015-01-01

The wide application of monopiles as foundations for offshore wind turbines has raised the issue of the suitability of the p –y curves proposed by API for lateral pile loading, since the latter were developed after full-scale tests on flexible and slender piles. This study investigates the role...... of the relative pile’s stiffness, when it is subjected to lateral load of large eccentricity. Employing centrifuge experiments, a hollow steel pile well instrumented with strain gauge pairs has been subjected to lateral load. The bending moment distribution of the model pile embedded in uniform, dense, dry sand...... was obtained under two different stress levels and two different embedment depths. Hence, the p – y curves were obtained providing an insight into the effect of the relative pile’s stiffness on the soil – pile interaction, while the effect of the installation process could also be evaluated....

Eccentric Macular Hole after Pars Plana Vitrectomy for Epiretinal Membrane Without Internal Limiting Membrane Peeling: A Case Report.

Science.gov (United States)

Garnavou-Xirou, Christina; Xirou, Tina; Kabanarou, Stamatina; Gkizis, Ilias; Velissaris, Stavros; Chatziralli, Irini

2017-12-01

Postoperative eccentric macular hole formation is an uncommon complication after pars plana vitrectomy (PPV) without internal limiting membrane (ILM) peeling for the treatment of epiretinal membrane (ERM). We present a case of eccentric macular hole formation after PPV for ERM without ILM peeling. A 68-year-old male patient presented with ERM and visual acuity of 6/24 in his left eye. He underwent 23-gauge PPV without ILM peeling for treatment of ERM. One week postoperatively the retina was attached and the epiretinal membrane was successfully removed, while visual acuity was 6/9. One month after PPV, a single eccentric retinal hole below the macula was detected using fundoscopy and subsequently confirmed by optical coherence tomography. At this time the visual acuity was 6/9 and the patient reported no symptoms. No further intervention was attempted and at the 9-month follow-up, the visual acuity and the size of the eccentric macular hole remained stable. Eccentric macular holes can be developed after PPV even without ILM peeling and are usually managed conservatively by observation.

Moment measurements in dynamic and quasi-static spine segment testing using eccentric compression are susceptible to artifacts based on loading configuration.

Science.gov (United States)

Van Toen, Carolyn; Carter, Jarrod W; Oxland, Thomas R; Cripton, Peter A

2014-12-01

The tolerance of the spine to bending moments, used for evaluation of injury prevention devices, is often determined through eccentric axial compression experiments using segments of the cadaver spine. Preliminary experiments in our laboratory demonstrated that eccentric axial compression resulted in "unexpected" (artifact) moments. The aim of this study was to evaluate the static and dynamic effects of test configuration on bending moments during eccentric axial compression typical in cadaver spine segment testing. Specific objectives were to create dynamic equilibrium equations for the loads measured inferior to the specimen, experimentally verify these equations, and compare moment responses from various test configurations using synthetic (rubber) and human cadaver specimens. The equilibrium equations were verified by performing quasi-static (5 mm/s) and dynamic experiments (0.4 m/s) on a rubber specimen and comparing calculated shear forces and bending moments to those measured using a six-axis load cell. Moment responses were compared for hinge joint, linear slider and hinge joint, and roller joint configurations tested at quasi-static and dynamic rates. Calculated shear force and bending moment curves had similar shapes to those measured. Calculated values in the first local minima differed from those measured by 3% and 15%, respectively, in the dynamic test, and these occurred within 1.5 ms of those measured. In the rubber specimen experiments, for the hinge joint (translation constrained), quasi-static and dynamic posterior eccentric compression resulted in flexion (unexpected) moments. For the slider and hinge joints and the roller joints (translation unconstrained), extension ("expected") moments were measured quasi-statically and initial flexion (unexpected) moments were measured dynamically. In the cadaver experiments with roller joints, anterior and posterior eccentricities resulted in extension moments, which were unexpected and expected, for those

Impact Analysis of Reinforced Concrete Columns with Side Openings Subjected to Eccentric Axial Loads

Directory of Open Access Journals (Sweden)

Nazar Kamil Ali

2015-02-01

Full Text Available In this research the behavior of reinforced concrete columns with large side openings under impact loads was studied. The overall cross sectional dimensions of the column specimens used in this research were (500*1400 mm with total height of (14000 mm. The dimensions of side openings were (600*2000 mm. The column was reinforced with (20 mm diameter in longitudinal direction, while (12 mm ties were used in the transverse direction. The effect of eccentric impact loads on the horizontal and vertical displacement for this column was studied. Nonlinear finite element analysis has been carried out using ready computer finite element package (ANSYS to simulate the behavior of the reinforced concrete column with large side openings. Two load cases were considered in this investigation (C1, C2 with three different load values for each case. In the first case (C1 the loads was applied to one side of the column and in the second case (C2 the loads was applied to both sides. An Equilateral triangular load-time function was used for simulation the impact load results from gantry cranes supported by the column with total time duration (0.1 sec. In order to verify the analysis method, as no experimental data exist for comparing the obtained results, another analysis is made for tested conventional column under impact load at mid-height and good agreement has been obtained. For the above mentioned column, the maximum displacements were (33.3, 22.2 mm in the horizontal and longitudinal direction respectively, location of the maximum horizontal displacement was at the crown of the column. By comparing the results of the first loading case with the second one it is shown that in the horizontal direction, maximum displacement increases by (139%, (208%, and (147% respectively, also the maximum vertical displacement increases by (150%, (172%, and (172% respectively.

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

Science.gov (United States)

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

2018-02-01

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

The effect of active recovery on power performance during the bench press exercise.

Science.gov (United States)

Lopes, Felipe A S; Panissa, Valéria L G; Julio, Ursula F; Menegon, Elton M; Franchini, Emerson

2014-03-27

The objective of this study was to verify the effect of active and passive recovery on blood lactate concentration and power performance. Twelve male subjects were submitted to a maximal strength test in the the bench press, a maximal aerobic test in the bench step, and to four sets of bench press exercise performed as fast and as long as possible, using 80% of maximal strength when active or passive recovery was performed. The maximum number of repetitions, mean and peak power in eccentric and concentric phases were computed and blood lactate concentration was measured. Comparisons for the variables were made using a two-way variance analysis (recovery type and set numer) with repeated measures in the second factor. When significant differences were detected (p 2, 3, and 4; 2 > 3 and 4; 3 > 4). Mean and peak power in both eccentric and concentric phases also differed across sets (1 > 2, 3, and 4; 2 > 4). There was also a main effect for the recovery type, with lower values (p bench press exercise.

Influence of Wheel Eccentricity on Vertical Vibration of Suspended Monorail Vehicle: Experiment and Simulation

OpenAIRE

Kaikai Lv; Kaiyun Wang; Zhihui Chen; Chengbiao Cai; Lirong Guo

2017-01-01

This paper investigates the influence of wheel eccentricity on vertical vibration of suspended monorail vehicle based on experiment and simulation. Two sets of tests are conducted in the first Chinese suspended monorail, and the tested acceleration is analyzed and exhibited. A multibody dynamic model of the suspended monorail vehicle is established to simulate the vertical vibration of car body excited by wheel eccentricity. The results show that there are three factors which may cause an abn...

The eccentric, concentric strength relationship of the hamstring muscles in chronic low back pain.

Science.gov (United States)

Marshall, Paul W M; Mannion, Jamie; Murphy, Bernadette A

2010-02-01

The objective of this study was to measure hamstring muscle eccentric and concentric strength in individuals with and without low back pain (LBP). Two composite scores for the relative balance of eccentric to concentric strength at the different movement velocities were calculated (the DEC and SEC), to determine whether or not self perceived pain, disability, or fear avoidance measures were associated with hamstring strength characteristics. Cross-sectional repeated measures design. University laboratory. Fifteen individuals with chronic LBP and 15 matched controls. Isokinetic eccentric and concentric strength at 30 degrees s(-1) and 120 degrees s(-1)(.) Composite scores (DEC and SEC) based on peak torque were calculated to evaluate the relationship between the different muscle actions across the test velocities. Self report measures included the Oswestry disability index, general health and well being, fear avoidance, and pain. Eccentric/concentric strength ratio at 30 degrees s(-1) was higher for the LBP group (F(1,58)=4.81, p=0.032). The SEC was also higher for the LBP (F(1,58)=5.97, p=0.018). Fear avoidance beliefs and mental well-being were significantly associated with the SEC only in the LBP group (adjusted r(2)=0.26, (F(2,27)=5.8, p=.008). For the control group both the DEC and SEC were associated with self report measures. Matched differences between groups' for the SEC were best explained by fear avoidance beliefs about work (adjusted r(2)=0.12, F(1,28)=5.1, p=0.03). Reduced concentric relative to eccentric strength is best identified by the SEC. The SEC was significantly associated with impaired self report measures of fear avoidance and mental well being in individuals with LBP. Differences between groups for the SEC were best explained by fear avoidance beliefs about work.

Constraining stellar binary black hole formation scenarios with eLISA eccentricity measurements

Science.gov (United States)

Nishizawa, Atsushi; Sesana, Alberto; Berti, Emanuele; Klein, Antoine

2017-03-01

A space-based interferometer such as the evolved Laser Interferometer Space Antenna (eLISA) could observe a few to a few thousands of progenitors of black hole binaries (BHBs) similar to those recently detected by Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral, but some BHBs retain a measurable eccentricity at the low frequencies where eLISA is the most sensitive. The eccentricity of a BHB carries precious information about its formation channel: BHBs formed in the field, in globular clusters, or close to a massive black hole (MBH) have distinct eccentricity distributions in the eLISA band. We generate mock eLISA observations, folding in measurement errors, and using a Bayesian model selection, we study whether eLISA measurements can identify the BHB formation channel. We find that a handful of observations would suffice to tell whether BHBs were formed in the gravitational field of an MBH. Conversely, several tens of observations are needed to tell apart field formation from globular cluster formation. A 5-yr eLISA mission with the longest possible armlength is desirable to shed light on BHB formation scenarios.

Plyometric training improves voluntary activation and strength during isometric, concentric and eccentric contractions.

Science.gov (United States)

Behrens, Martin; Mau-Moeller, Anett; Mueller, Karoline; Heise, Sandra; Gube, Martin; Beuster, Nico; Herlyn, Philipp K E; Fischer, Dagmar-C; Bruhn, Sven

2016-02-01

This study investigated effects of plyometric training (6 weeks, 3 sessions/week) on maximum voluntary contraction (MVC) strength and neural activation of the knee extensors during isometric, concentric and eccentric contractions. Twenty-seven participants were randomly assigned to the intervention or control group. Maximum voluntary torques (MVT) during the different types of contraction were measured at 110° knee flexion (180°=full extension). The interpolated twitch technique was applied at the same knee joint angle during isometric, concentric and eccentric contractions to measure voluntary activation. In addition, normalized root mean square of the EMG signal at MVT was calculated. The twitch torque signal induced by electrical nerve stimulation at rest was used to evaluate training-related changes at the muscle level. In addition, jump height in countermovement jump was measured. After training, MVT increased by 20Nm (95% CI: 5-36Nm, P=0.012), 24Nm (95% CI: 9-40Nm, P=0.004) and 27Nm (95% CI: 7-48Nm, P=0.013) for isometric, concentric and eccentric MVCs compared to controls, respectively. The strength enhancements were associated with increases in voluntary activation during isometric, concentric and eccentric MVCs by 7.8% (95% CI: 1.8-13.9%, P=0.013), 7.0% (95% CI: 0.4-13.5%, P=0.039) and 8.6% (95% CI: 3.0-14.2%, P=0.005), respectively. Changes in the twitch torque signal of the resting muscle, induced by supramaximal electrical stimulation of the femoral nerve, were not observed, indicating no alterations at the muscle level, whereas jump height was increased. Given the fact that the training exercises consisted of eccentric muscle actions followed by concentric contractions, it is in particular relevant that the plyometric training increased MVC strength and neural activation of the quadriceps muscle regardless of the contraction mode. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

The effect of random mass, stiffness and eccentricity parameters on seismic response of torsional system

International Nuclear Information System (INIS)

Ghafory-Ashtiany, M.

2001-01-01

In this paper, the effect of random eccentricity, mass and stiffness parameter on the dynamic characteristics of structure and story shear and torsional response has been comprehensively examined. Numerical results are obtained for a five-story torsional building excited by random excitation with various damping ration and frequency parameter values using both approaches of response calculations-a more accurate complex mode and an approximate normal mode have been used. The results show that the introduction of eccentricity in a direction introduces torsional moments in the system and reduces the direct story shear. For a safe design, eccentricity should be neglected in the calculations for shear, and a value of 0.05 of radius of gyration for calculation of torsional moment should be considered, even if a structure is intended to be symmetrical

Burn-out, Circumferential Film Flow Distribution and Pressure Drop for an Eccentric Annulus with Heated Rod

DEFF Research Database (Denmark)

Andersen, P. S.; Jensen, A.; Mannov, G.

1974-01-01

Measurements of (1) burn-out, (2) circumferential film flow distribution, and (3) pressure drop in a 17 × 27.2 × 3500 mm concentric and eccentric annulus geometry are presented. The eccentric displacement was varied between 0 and 3 mm. The working fluid was water. Burn-out curves at 70 bar...... flow variation on burn-out is discussed....

Computer task performance by subjects with Duchenne muscular dystrophy.

Science.gov (United States)

Malheiros, Silvia Regina Pinheiro; da Silva, Talita Dias; Favero, Francis Meire; de Abreu, Luiz Carlos; Fregni, Felipe; Ribeiro, Denise Cardoso; de Mello Monteiro, Carlos Bandeira

2016-01-01

Two specific objectives were established to quantify computer task performance among people with Duchenne muscular dystrophy (DMD). First, we compared simple computational task performance between subjects with DMD and age-matched typically developing (TD) subjects. Second, we examined correlations between the ability of subjects with DMD to learn the computational task and their motor functionality, age, and initial task performance. The study included 84 individuals (42 with DMD, mean age of 18±5.5 years, and 42 age-matched controls). They executed a computer maze task; all participants performed the acquisition (20 attempts) and retention (five attempts) phases, repeating the same maze. A different maze was used to verify transfer performance (five attempts). The Motor Function Measure Scale was applied, and the results were compared with maze task performance. In the acquisition phase, a significant decrease was found in movement time (MT) between the first and last acquisition block, but only for the DMD group. For the DMD group, MT during transfer was shorter than during the first acquisition block, indicating improvement from the first acquisition block to transfer. In addition, the TD group showed shorter MT than the DMD group across the study. DMD participants improved their performance after practicing a computational task; however, the difference in MT was present in all attempts among DMD and control subjects. Computational task improvement was positively influenced by the initial performance of individuals with DMD. In turn, the initial performance was influenced by their distal functionality but not their age or overall functionality.

Eccentric contractions affect muscle membrane phospholipid fatty acid composition in rats

DEFF Research Database (Denmark)

Helge, Jørn Wulff; Therkildsen, K J; Jørgensen, T B

2001-01-01

This study investigated if prior eccentric contractions, and thus mechanical strain and muscle damage, exert an effect on the muscle membrane phospholipid fatty acid composition in rats, and whether a possible effect could be attenuated by dietary supplements. Twenty-three rats were randomised...... muscle, was excised from both legs. In the muscles stimulated to contract eccentrically, compared to the control muscles, the proportion of arachidonic acid, C20:4,n-6 (17.7 +/- 0.6; 16.4 +/- 0.4% of total fatty acids, respectively) and docosapentanoeic acid, C22:5,n-3 (2.9 +/- 0.1 and 2.7 +/- 0.......1% of total fatty acids, respectively) was uniformly higher across groups (P fatty acids) compared to the control leg (38.2 +/- 0...

Analysis of PM Magnetization Field Effects on the Unbalanced Magnetic Forces due to Rotor Eccentricity in BLDC Motors

Directory of Open Access Journals (Sweden)

S. Mahdiuon-Rad

2013-08-01

Full Text Available This paper investigates both static and dynamic eccentricities in single phase brushless DC (BLDC motors and analyzes the effect of the PM magnetization field on unbalanced magnetic forces acting on the rotor. Three common types of PM magnetization field patterns including radial, parallel and sinusoidal magnetizations are considered. In both static and dynamic eccentricities, harmonic components of the unbalanced magnetic forces on the rotor are extracted and analyzed. Based on simulation results, the magnetization fields that produce the lowest and highest unbalanced magnetic forces are determined in rotor eccentricity conditions.

The impact assessment of eccentric installation and roughness change in piping on the orifice flow measurement

International Nuclear Information System (INIS)

Nishi, Y.; Eguchi, Y.; Nishihara, T.; Kanai, T.; Kondo, M.

2012-01-01

In orifice flowmeters used in nuclear power plants, requirements for the inner surface roughness of upstream piping and eccentric installation exist depending on certain standards. If these cannot be satisfied based on the installation condition, an appropriate error margin must be considered, although this remains to be clarified. In this research, quantitative data concerning the relative error of orifice flowmeters were obtained during experiments with the parameters of the inner surface roughness of upstream piping and the installation eccentricity of the orifice hole. The maximum Reynolds number of the experimental facility is about 1.6x10 6 . In orifice flowmeters, the flow rate is calculated based on the differential pressure between upstream and downstream orifices and the peculiar discharge coefficient C. The latter value shows an upward trend with increasing roughness of piping, while change of 0.3% of C was observed in terms of roughness (case 2), which approaches the limits of the JIS standard. With significant roughness (Case 3) that exceeds five times the JIS standard, C is shown to have increased by about 1%. No influence was observed by varying the direction of eccentric installation, hence this was fixed and the amount of eccentricity was considered. Change in C of about 0.25% was observed when around twice the standard level of eccentricity was applied. The error margin data under conditions exceeding the JIS standard for the orifice flowmeter was obtained. (authors)

Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

International Nuclear Information System (INIS)

Feng, Huicheng; Wong, Teck Neng; Marcos; Che, Zhizhao

2016-01-01

Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

Energy Technology Data Exchange (ETDEWEB)

Feng, Huicheng; Wong, Teck Neng, E-mail: mtnwong@ntu.edu.sg; Marcos [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Che, Zhizhao [State Key Laboratory of Engines, Tianjin University, Tianjin 300072 (China)

2016-06-15

Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

Sonographic evaluation of the immediate effects of eccentric heel drop exercise on Achilles tendon and gastrocnemius muscle stiffness using shear wave elastography

Science.gov (United States)

Leung, Wilson K.C.; Chu, KL

2017-01-01

Background Mechanical loading is crucial for muscle and tendon tissue remodeling. Eccentric heel drop exercise has been proven to be effective in the management of Achilles tendinopathy, yet its induced change in the mechanical property (i.e., stiffness) of the Achilles tendon (AT), medial and lateral gastrocnemius muscles (MG and LG) was unknown. Given that shear wave elastography has emerged as a powerful tool in assessing soft tissue stiffness with promising intra- and inter-operator reliability, the objective of this study was hence to characterize the stiffness of the AT, MG and LG in response to an acute bout of eccentric heel drop exercise. Methods Forty-five healthy young adults (36 males and nine females) performed 10 sets of 15-repetition heel drop exercise on their dominant leg with fully-extended knee, during which the AT and gastrocnemius muscles, but not soleus, were highly stretched. Before and immediately after the heel drop exercise, elastic moduli of the AT, MG and LG were measured by shear wave elastography. Results After the heel drop exercise, the stiffness of AT increased significantly by 41.8 + 33.5% (P eccentric heel drop exercise. The findings from this pilot study shed some light on how and to what extent the AT and gastrocnemius muscles mechanically responds to an isolated set of heel drop exercise. Taken together, appropriate eccentric load might potentially benefit mechanical adaptations of the AT and gastrocnemius muscles in the rehabilitation of patients with Achilles tendinopathy. PMID:28740756

Fast prediction and evaluation of eccentric inspirals using reduced-order models

Science.gov (United States)

Barta, Dániel; Vasúth, Mátyás

2018-06-01

A large number of theoretically predicted waveforms are required by matched-filtering searches for the gravitational-wave signals produced by compact binary coalescence. In order to substantially alleviate the computational burden in gravitational-wave searches and parameter estimation without degrading the signal detectability, we propose a novel reduced-order-model (ROM) approach with applications to adiabatic 3PN-accurate inspiral waveforms of nonspinning sources that evolve on either highly or slightly eccentric orbits. We provide a singular-value decomposition-based reduced-basis method in the frequency domain to generate reduced-order approximations of any gravitational waves with acceptable accuracy and precision within the parameter range of the model. We construct efficient reduced bases comprised of a relatively small number of the most relevant waveforms over three-dimensional parameter-space covered by the template bank (total mass 2.15 M⊙≤M ≤215 M⊙ , mass ratio 0.01 ≤q ≤1 , and initial orbital eccentricity 0 ≤e0≤0.95 ). The ROM is designed to predict signals in the frequency band from 10 Hz to 2 kHz for aLIGO and aVirgo design sensitivity. Beside moderating the data reduction, finer sampling of fiducial templates improves the accuracy of surrogates. Considerable increase in the speedup from several hundreds to thousands can be achieved by evaluating surrogates for low-mass systems especially when combined with high-eccentricity.

PSR J1618-3921: a recycled pulsar in an eccentric orbit

Science.gov (United States)

Octau, F.; Cognard, I.; Guillemot, L.; Tauris, T. M.; Freire, P. C. C.; Desvignes, G.; Theureau, G.

2018-04-01

Context. The 11.99 ms pulsar PSR J1618-3921 orbits a He white dwarf companion of probably low mass with a period of 22.7 d. The pulsar was discovered in a survey of the intermediate Galactic latitudes at 1400 MHz that was conducted with the Parkes radio telescope in the late 1990s. Although PSR J1618-3921 was discovered more than 15 years ago, only limited information has been published about this pulsar, which has a surprisingly high orbital eccentricity (e ≃ 0.027) considering its high spin frequency and the likely low mass of the companion. Aims: The focus of this work is a precise measurement of the spin and the astrometric and orbital characteristics of PSR J1618-3921. This was done with timing observations made at the Nançay Radio Telescope from 2009 to 2017. Methods: We analyzed the timing data recorded at the Nançay Radio Telescope over several years to characterize the properties of PSR J1618-3921. A rotation ephemeris for this pulsar was obtained by analyzing the arrival times of the radio pulses at the telescope. Results: We confirm the unusual eccentricity of PSR J1618-3921 and discuss several hypotheses regarding its formation in the context of other discoveries of recycled pulsars in eccentric orbits.

Xanthine oxidase in human skeletal muscle following eccentric exercise

DEFF Research Database (Denmark)

Hellsten, Ylva; Frandsen, Ulrik; Orthenblad, N.

1997-01-01

the increase in xanthine oxidase in the muscle there were no detectable changes in the levels of muscle malondialdehyde or in plasma antioxidant capacity up to 4 days post-exercise. 5. It is concluded that eccentric exercise leads to an increased level of xanthine oxidase in human muscle and that the increase...

Analytical modeling of large amplitude free vibration of non-uniform beams carrying a both transversely and axially eccentric tip mass

Science.gov (United States)

Malaeke, Hasan; Moeenfard, Hamid

2016-03-01

The objective of this paper is to study large amplitude flexural-extensional free vibration of non-uniform cantilever beams carrying a both transversely and axially eccentric tip mass. The effects of variable axial force is also taken into account. Hamilton's principle is utilized to obtain the partial differential equations governing the nonlinear vibration of the system as well as the corresponding boundary conditions. A numerical finite difference scheme is proposed to find the natural frequencies and mode shapes of the system which is validated specifically for a beam with linearly varying cross section. Using a single mode approximation in conjunction with the Lagrange method, the governing equations are reduced to a set of two nonlinear ordinary differential equations in terms of end displacement components of the beam which are coupled due to the presence of the transverse eccentricity. These temporal coupled equations are then solved analytically using the multiple time scales perturbation technique. The obtained analytical results are compared with the numerical ones and excellent agreement is observed. The qualitative and quantitative knowledge resulting from this research is expected to enable the study of the effects of eccentric tip mass and non-uniformity on the large amplitude flexural-extensional vibration of beams for improved dynamic performance.

Phase-Shifted Eccentric Core Fiber Bragg Grating Fabricated by Electric Arc Discharge for Directional Bending Measurement.

Science.gov (United States)

Ouyang, Yang; Liu, Jianxia; Xu, Xiaofeng; Zhao, Yujia; Zhou, Ai

2018-04-11

A phase-shifted eccentric core fiber Bragg grating (PS-ECFBG) fabricated by electric arc discharge (EAD) is presented and demonstrated. It is composed of a fraction of eccentric core fiber fusion spliced in between two pieces of commercial single mode fibers, where a PS-FBG was written. The EAD in this work could flexibly change the amount of phase-shift by changing the discharge number or discharge duration. Because of the offset location of the eccentric core and the ultra-narrow resonant peak of the PS-ECFBG, it has a higher accuracy for measuring the directional bend. The elongation and compression of the eccentric core keep the magnitude of phase shift still unchanged during the bending process. The bending sensitivities of the PS-ECFBG at two opposite most sensitive directions are 57.4 pm/m -1 and -51.5 pm/m -1 , respectively. Besides, the PS-ECFBG has the potential to be a tunable narrow bandpass filter, which has a wider bi-directional adjustable range because of the bending responses. The strain and temperature sensitivities of the PS-ECFBG are experimentally measured as well, which are 0.70 pm/με and 8.85 pm/°C, respectively.

Highly eccentric hip-hop solutions of the 2 N-body problem

Science.gov (United States)

Barrabés, Esther; Cors, Josep M.; Pinyol, Conxita; Soler, Jaume

2010-02-01

We show the existence of families of hip-hop solutions in the equal-mass 2 N-body problem which are close to highly eccentric planar elliptic homographic motions of 2 N bodies plus small perpendicular non-harmonic oscillations. By introducing a parameter ɛ, the homographic motion and the small amplitude oscillations can be uncoupled into a purely Keplerian homographic motion of fixed period and a vertical oscillation described by a Hill type equation. Small changes in the eccentricity induce large variations in the period of the perpendicular oscillation and give rise, via a Bolzano argument, to resonant periodic solutions of the uncoupled system in a rotating frame. For small ɛ≠0, the topological transversality persists and Brouwer’s fixed point theorem shows the existence of this kind of solutions in the full system.

Effectiveness of Shockwave Treatment Combined With Eccentric Training for Patellar Tendinopathy: A Double-Blinded Randomized Study

OpenAIRE

Thijs, Karin M.; Zwerver, Johannes; Backx, Frank J. G.; Steeneken, Victor; Rayer, Stephan; Groenenboom, Petra; Moen, Maarten H.

2017-01-01

OBJECTIVE: To evaluate the effectiveness of a combined treatment of focused shockwave therapy (ESWT) and eccentric training compared with sham-shockwave therapy (placebo) and eccentric training in participants with patellar tendinopathy (PT) after 24 weeks. DESIGN: Randomized controlled trial. SETTING: Sports medicine departments of a university hospital and a general hospital in the Netherlands. PARTICIPANTS: Fifty-two physically active male and female participants with a clinical diagnosis ...

Eccentric Exercise in Treatment of Patellar Tendinopathy in High Level Basketball Players. A Randomized Clinical Trial.

OpenAIRE

Sosa, Carlos; Lorenzo Calvo, Alberto; Jiménez, Sergio L.; Bonfanti, Noelia

2014-01-01

Chronic patellar tendinopathy is a common pathology in sporting population. To date, there is no agreed upon protocol as election treatment. Eccentric exercises have been used with satisfactory outcomes. The purpose of this trial is compare the effects of two eccentric exercise protocols. 0.146 SJR (2014) Q4, 199/231 Health (social science), 131/169 Physical therapy, sports therapy and rehabilitation, 119/128 Sports sciences UEM

Subjective and objective performance assessment : Performance pay at Trelleborg Forsheda AB

OpenAIRE

Luotonen, David; Hasselström, Markus

2009-01-01

  The purpose of this thesis is to understand the opinions and potential effects of objective and subjective assessments of performance as a basis for performance pay for blue-collar workers. The study takes a qualitative approach to find out how and why four companies - Trelleborg Forsheda, Finnveden Powertrain, Isaberg Rapid and Parker Hannifin- work with salaries, incentive system and performance assessment the way they do. The concept of individual salary is central in this thesis, and in...

Eccentric and Isometric Hip Adduction Strength in Male Soccer Players With and Without Adductor-Related Groin Pain: An Assessor-Blinded Comparison.

Science.gov (United States)

Thorborg, Kristian; Branci, Sonia; Nielsen, Martin Peter; Tang, Lars; Nielsen, Michael Bachmann; Hölmich, Per

2014-02-01

Adductor-related pain is the most common clinical finding in soccer players with groin pain and can be a long-standing problem affecting physical function and performance. Hip adductor weakness has been suggested to be associated with this clinical entity, although it has never been investigated. To investigate whether isometric and eccentric hip strength are decreased in soccer players with adductor-related groin pain compared with asymptomatic soccer controls. The hypothesis was that players with adductor-related groin pain would have lower isometric and eccentric hip adduction strength than players without adductor-related groin pain. Cross-sectional study; Level of evidence, 3. Male elite and subelite players from 40 teams were contacted. In total, 28 soccer players with adductor-related groin pain and 16 soccer players without adductor-related groin pain (asymptomatic controls) were included in the study. In primary analysis, the dominant legs of 21 soccer players with adductor-related groin pain (≥4 weeks duration) were compared with the dominant legs of 16 asymptomatic controls using a cross-sectional design. The mean age of the symptomatic players was 24.5 ± 2.5 years, and the mean age of the asymptomatic controls was 22.9 ± 2.4 years. Isometric hip strength (adduction, abduction, and flexion) and eccentric hip strength (adduction) were assessed with a handheld dynamometer using reliable test procedures and a blinded assessor. Eccentric hip adduction strength was lower in soccer players with adductor-related groin pain in the dominant leg (n = 21) compared with asymptomatic controls (n = 16), namely 2.47 ± 0.49 versus 3.12 ± 0.43 N·m/kg, respectively (P strength differences were observed between symptomatic players and asymptomatic controls for the dominant leg (P = .35-.84). Large eccentric hip adduction strength deficits were found in soccer players with adductor-related groin pain compared with asymptomatic soccer players, while no isometric

Einstein@Home DISCOVERY OF A PALFA MILLISECOND PULSAR IN AN ECCENTRIC BINARY ORBIT

Energy Technology Data Exchange (ETDEWEB)

Knispel, B.; Allen, B. [Leibniz Universität, Hannover, D-30167 Hannover (Germany); Lyne, A. G.; Stappers, B. W. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Freire, P. C. C.; Lazarus, P. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Aulbert, C.; Bock, O.; Eggenstein, H.-B.; Fehrmann, H. [Max-Planck-Institut für Gravitationsphysik, Callinstr. 38, D-30167 Hannover (Germany); Bogdanov, S.; Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Brazier, A.; Chatterjee, S.; Cordes, J. M. [Department of Astronomy and Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States); Cardoso, F. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Crawford, F. [Department of Physics and Astronomy, Franklin and Marshall College, Lancaster, PA 17604-3003 (United States); Deneva, J. S. [National Research Council, resident at the Naval Research Laboratory, Washington, DC 20375 (United States); Ferdman, R. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Hessels, J. W. T., E-mail: benjamin.knispel@aei.mpg.de [ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); and others

2015-06-10

We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 (P = 4.3 ms) in a binary system with an eccentric (e = 0.08) 22 day orbit in Pulsar Arecibo L-band Feed Array survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 M{sub ⊙} and is most likely a white dwarf (WD). Fully recycled MSPs like this one are thought to be old neutron stars spun-up by mass transfer from a companion star. This process should circularize the orbit, as is observed for the vast majority of binary MSPs, which predominantly have orbital eccentricities e < 0.001. However, four recently discovered binary MSPs have orbits with 0. 027 < e < 0.44; PSR J1950+2414 is the fifth such system to be discovered. The upper limits for its intrinsic spin period derivative and inferred surface magnetic field strength are comparable to those of the general MSP population. The large eccentricities are incompatible with the predictions of the standard recycling scenario: something unusual happened during their evolution. Proposed scenarios are (a) initial evolution of the pulsar in a triple system which became dynamically unstable, (b) origin in an exchange encounter in an environment with high stellar density, (c) rotationally delayed accretion-induced collapse of a super-Chandrasekhar WD, and (d) dynamical interaction of the binary with a circumbinary disk. We compare the properties of all five known eccentric MSPs with the predictions of these formation channels. Future measurements of the masses and proper motion might allow us to firmly exclude some of the proposed formation scenarios.

Experimental study and CFD simulation of rotational eccentric cylinder in a magnetorheological fluid

Science.gov (United States)

Omidbeygi, F.; Hashemabadi, S. H.

2012-07-01

In this study, a magnetorheological (MR) fluid is prepared using carbonyl iron filings and low viscosity lubricating oil. The effects of magnetic field and weight percentage of particles on the viscosity of the MR fluid have been measured using a rotational viscometer. The yield stress under an applied magnetic field was also obtained experimentally. In the absence of an applied magnetic field, the MR fluid behaves as a Newtonian fluid. When the magnetic field is applied, the MR fluid behaves like Bingham plastics with a magnetic field dependent yield stress. Afterward, the results compared with those of CFD simulation of two eccentric cylinders in the MR fluid. Results show that the influences of MR effects, caused by the applied magnetic field, on the model characteristics are significant and not negligible. The viscosity is enhanced by increasing of the magnetic field, eccentricity ratio and weight percentage of suspensions. The MR effects and increasing of weight percentage and eccentricity ratio also provide an enhancement in the yield stresses and required total torque for rotation of inner cylinder. Also the simulation results indicate a good representation of the experiment by the model.

Analysis for Eccentric Multi Canister Overpack (MCO) Drops at the Canister Storage Building (CSB) (CSB-S-0073)

Energy Technology Data Exchange (ETDEWEB)

TU, K.C.

1999-10-08

Multi-Canister Overpacks (MCOs) containing spent nuclear fuel (SNF) will be routinely handled at the Canister Storage Building (CSB) during fuel movement operations in the SNF Project. This analysis was performed to investigate the potential for damage from an eccentric accidental drop onto the standard storage tube, overpack tube, service station, or sample/weld station. Appendix D was added to the FDNW document to include the peer Review Comment Record & transmittal record.

Analysis for Eccentric Multi Canister Overpack (MCO) Drops at the Canister Storage Building (CSB) (CSB-S-0073)

International Nuclear Information System (INIS)

TU, K.C.

1999-01-01

Multi-Canister Overpacks (MCOs) containing spent nuclear fuel (SNF) will be routinely handled at the Canister Storage Building (CSB) during fuel movement operations in the SNF Project. This analysis was performed to investigate the potential for damage from an eccentric accidental drop onto the standard storage tube, overpack tube, service station, or sample/weld station. Appendix D was added to the FDNW document to include the peer Review Comment Record and transmittal record

Age-related functional changes and susceptibility to eccentric contraction-induced damage in skeletal muscle cell.

Science.gov (United States)

Choi, Seung-Jun

2016-09-01

Depending upon external loading conditions, skeletal muscles can either shorten, lengthen, or remain at a fixed length as they produce force. Fixed-end or isometric contractions stabilize joints and allow muscles to act as active struts during locomotion. Active muscles dissipate energy when they are lengthened by an external force that exceeds their current force producing capacity. These unaccustomed eccentric activities often lead to muscle weakness, soreness, and inflammation. During aging, the ability to produce force under these conditions is reduced and appears to be due to not only reductions in muscle mass but also to alterations in the basic mechanisms of contraction. These alterations include impairments in the excitation-contraction process, and the action of the cross-bridges. Also, it is well known that age-related skeletal muscle atrophy is characterized by a preferential atrophy of fast fibers, and increased susceptibility to fast muscle fiber when aged muscles are exposed to eccentric contraction followed by the impaired recovery process has been reported. Taken together, the selective loss of fast muscle fiber in aged muscle could be affected by eccentric-induced muscle damage, which has significant implication to identify the etiology of the age-related functional changes. Therefore, in this review the alteration of age-related muscle function and its impact to/of eccentric induced muscle damage and recovery will be addressed in detail.

Age-related functional changes and susceptibility to eccentric contraction-induced damage in skeletal muscle cell

Directory of Open Access Journals (Sweden)

Seung-Jun Choi

2016-09-01

Full Text Available Depending upon external loading conditions, skeletal muscles can either shorten, lengthen, or remain at a fixed length as they produce force. Fixed-end or isometric contractions stabilize joints and allow muscles to act as active struts during locomotion. Active muscles dissipate energy when they are lengthened by an external force that exceeds their current force producing capacity. These unaccustomed eccentric activities often lead to muscle weakness, soreness, and inflammation. During aging, the ability to produce force under these conditions is reduced and appears to be due to not only reductions in muscle mass but also to alterations in the basic mechanisms of contraction. These alterations include impairments in the excitation–contraction process, and the action of the cross-bridges. Also, it is well known that age-related skeletal muscle atrophy is characterized by a preferential atrophy of fast fibers, and increased susceptibility to fast muscle fiber when aged muscles are exposed to eccentric contraction followed by the impaired recovery process has been reported. Taken together, the selective loss of fast muscle fiber in aged muscle could be affected by eccentric-induced muscle damage, which has significant implication to identify the etiology of the age-related functional changes. Therefore, in this review the alteration of age-related muscle function and its impact to/of eccentric induced muscle damage and recovery will be addressed in detail.

The effect of eccentric exercise on injured patellar tendon healing in rats: a gene expression study

OpenAIRE

Yagishita, Masafumi

2011-01-01

Recently, clinical studies have suggested that eccentric exercise can be beneficial for patellar tendinopathy. It is known that loading induces collagen synthesis in tendon, but the mechanisms responsible for mediating this effect are still unclear. We hypothesized that loading-induced expression of collagen depends on a specific contraction type. Eccentric exercise induces a more beneficial healing response than concentric exercise. Two longitudinal incisions were made in rat patellar tendon...

Limits on stellar companions to exoplanet host stars with eccentric planets

International Nuclear Information System (INIS)

Kane, Stephen R.; Hinkel, Natalie R.; Howell, Steve B.; Horch, Elliott P.; Feng, Ying; Wright, Jason T.; Ciardi, David R.; Everett, Mark E.; Howard, Andrew W.

2014-01-01

Though there are now many hundreds of confirmed exoplanets known, the binarity of exoplanet host stars is not well understood. This is particularly true of host stars that harbor a giant planet in a highly eccentric orbit since these are more likely to have had a dramatic dynamical history that transferred angular momentum to the planet. Here we present observations of four exoplanet host stars that utilize the excellent resolving power of the Differential Speckle Survey Instrument on the Gemini North telescope. Two of the stars are giants and two are dwarfs. Each star is host to a giant planet with an orbital eccentricity >0.5 and whose radial velocity (RV) data contain a trend in the residuals to the Keplerian orbit fit. These observations rule out stellar companions 4-8 mag fainter than the host star at passbands of 692 nm and 880 nm. The resolution and field of view of the instrument result in exclusion radii of 0.''05-1.''4, which excludes stellar companions within several AU of the host star in most cases. We further provide new RVs for the HD 4203 system that confirm that the linear trend previously observed in the residuals is due to an additional planet. These results place dynamical constraints on the source of the planet's eccentricities, place constraints on additional planetary companions, and inform the known distribution of multiplicity amongst exoplanet host stars.

Eccentric LVH healing after starting renal replacement therapy.

Science.gov (United States)

Vertolli, Ugo; Lupia, Mario; Naso, Agostino

2002-01-01

Hypertension and left ventricular hypertrophy (LVH) are commonly associated in patients with CRF starting RDT. We report a case of eccentric LVH with marked dilatation and subsequent mitral incompetence of +3/4 that disappeared after three months of standard hemodialysis. Mrs SN, 62 years old, starting HD, had an echocardiography because of dyspnoea; the echo showed: dilated left atrium (78 ml/m2), moderately dilated left ventricle with normal systolic function (TDV 81 ml/m2, EF 66%), an increased ventricular mass (120 gr/m2) and a high grade mitral incompetence +3/4. After three months standard RDT and a dry weight only 2 kg less, the patients was normotensive without therapy, a cardiac angiogram with a hemodynamic study was performed as a pre-transplant workout: a normal left ventricle was found with normal systolic function (TDV 66, TSV 17, GS 49, EF 75%), and a perfectly competent mitral valve (reflux disappeared). The coronary angiography did not reveal critical stenosis. A new echocardiography confinned the data of the hemodynamic study: hypertensive cardiomiopathy with normal systolic function. After one year the patient has been transplanted, with a good renal function and the cardiac echo unchanged. Relieving uremic toxicity ameliorated the cardiac performance in this particular patient.

SECRETLY ECCENTRIC: THE GIANT PLANET AND ACTIVITY CYCLE OF GJ 328

International Nuclear Information System (INIS)

Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Boss, Alan P.

2013-01-01

We announce the discovery of a ∼2 Jupiter-mass planet in an eccentric 11 yr orbit around the K7/M0 dwarf GJ 328. Our result is based on 10 years of radial velocity (RV) data from the Hobby-Eberly and Harlan J. Smith telescopes at McDonald Observatory, and from the Keck Telescope at Mauna Kea. Our analysis of GJ 328's magnetic activity via the Na I D features reveals a long-period stellar activity cycle, which creates an additional signal in the star's RV curve with amplitude 6-10 m s –1 . After correcting for this stellar RV contribution, we see that the orbit of the planet is more eccentric than suggested by the raw RV data. GJ 328b is currently the most massive, longest-period planet discovered around a low-mass dwarf

Synthesis of eccentric titania-silica core-shell and composite particles

NARCIS (Netherlands)

Demirors, A.F.; van Blaaderen, A.; Imhof, A.

2009-01-01

We describe a novel method to synthesize colloidal particles with an eccentric core-shell structure. Titania-silica core-shell particles were synthesized by silica coating of porous titania particles under Sto¨ber (Sto¨ber et al. J. Colloid Interface Sci. 1968, 26, 62) conditions. We can control

Detection of Static Eccentricity Fault in Saturated Induction Motors by ...

African Journals Online (AJOL)

Unfortunately, motor current signature analysis (MCSA) cannot detect the small degrees of the purely static eccentricity (SE) defects, while the air-gap magnetic flux signature analysis (FSA) is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE) method. In order to show the ...

The formation of eccentric compact binary inspirals and the role of gravitational wave emission in binary-single stellar encounters

International Nuclear Information System (INIS)

Samsing, Johan; MacLeod, Morgan; Ramirez-Ruiz, Enrico

2014-01-01

The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the LIGO band. In this paper, we study binary-single stellar scatterings occurring in dense stellar systems as a source of eccentrically inspiraling binaries. Many interactions between compact binaries and single objects are characterized by chaotic resonances in which the binary-single system undergoes many exchanges before reaching a final state. During these chaotic resonances, a pair of objects has a non-negligible probability of experiencing a very close passage. Significant orbital energy and angular momentum are carried away from the system by gravitational wave (GW) radiation in these close passages, and in some cases this implies an inspiral time shorter than the orbital period of the bound third body. We derive the cross section for such dynamical inspiral outcomes through analytical arguments and through numerical scattering experiments including GW losses. We show that the cross section for dynamical inspirals grows with increasing target binary semi-major axis a and that for equal-mass binaries it scales as a 2/7 . Thus, we expect wide target binaries to predominantly contribute to the production of these relativistic outcomes. We estimate that eccentric inspirals account for approximately 1% of dynamically assembled non-eccentric merging binaries. While these events are rare, we show that binary-single scatterings are a more effective formation channel than single-single captures for the production of eccentrically inspiraling binaries, even given modest binary fractions.

Phase-Shifted Eccentric Core Fiber Bragg Grating Fabricated by Electric Arc Discharge for Directional Bending Measurement

Directory of Open Access Journals (Sweden)

Yang Ouyang

2018-04-01

Full Text Available A phase-shifted eccentric core fiber Bragg grating (PS-ECFBG fabricated by electric arc discharge (EAD is presented and demonstrated. It is composed of a fraction of eccentric core fiber fusion spliced in between two pieces of commercial single mode fibers, where a PS-FBG was written. The EAD in this work could flexibly change the amount of phase-shift by changing the discharge number or discharge duration. Because of the offset location of the eccentric core and the ultra-narrow resonant peak of the PS-ECFBG, it has a higher accuracy for measuring the directional bend. The elongation and compression of the eccentric core keep the magnitude of phase shift still unchanged during the bending process. The bending sensitivities of the PS-ECFBG at two opposite most sensitive directions are 57.4 pm/m−1 and −51.5 pm/m−1, respectively. Besides, the PS-ECFBG has the potential to be a tunable narrow bandpass filter, which has a wider bi-directional adjustable range because of the bending responses. The strain and temperature sensitivities of the PS-ECFBG are experimentally measured as well, which are 0.70 pm/με and 8.85 pm/°C, respectively.

Changes in Achilles tendon mechanical properties following eccentric heel drop exercise are specific to the free tendon.

Science.gov (United States)

Obst, S J; Newsham-West, R; Barrett, R S

2016-04-01

Mechanical loading of the Achilles tendon during isolated eccentric contractions could induce immediate and region-dependent changes in mechanical properties. Three-dimensional ultrasound was used to examine the immediate effect of isolated eccentric exercise on the mechanical properties of the distal (free tendon) and proximal (gastrocnemii) regions of the Achilles tendon. Participants (n = 14) underwent two testing sessions in which tendon measurements were made at rest and during a 30% and 70% isometric plantar flexion contractions immediately before and after either: (a) 3 × 15 eccentric heel drops or (b) 10-min rest. There was a significant time-by-session interaction for free tendon length and strain for all loading conditions (P tendon length and strain at all contraction intensities after eccentric exercise (P tendon for any of the measured parameters. Immediate changes in Achilles tendon mechanical properties were specific to the free tendon and consistent with changes due to mechanical creep. These findings suggest that the mechanical properties of the free tendon may be more vulnerable to change with exercise compared with the gastrocnemii aponeurosis or tendon. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of the 6PBT stirrer eccentricity and off-bottom clearance on mixing of pseudoplastic fluid in a stirred tank

Science.gov (United States)

Luan, Deyu; Zhang, Shengfeng; Wei, Xing; Duan, Zhenya

The aim of this work is to investigate the effect of the shaft eccentricity on the flow field and mixing characteristics in a stirred tank with the novel stirrer composed of perturbed six-bent-bladed turbine (6PBT). The difference between coaxial and eccentric agitations is studied using computational fluid dynamics (CFD) simulations combined with standard k-ε turbulent equations, that offer a complete image of the three-dimensional flow field. In order to determine the capability of CFD to forecast the mixing process, particle image velocimetry (PIV), which provide an accurate representation of the time-averaged velocity, was used to measure fluid velocity. The test liquid used was 1.25% (wt) xanthan gum solution, a pseudoplastic fluid with a yield stress. The comparison of the experimental and simulated mean flow fields has demonstrated that calculations based on Reynolds-averaged Navier-Stokes equations are suitable for obtaining accurate results. The effects of the shaft eccentricity and the stirrer off-bottom distance on the flow model, mixing time and mixing efficiency were extensively analyzed. It is observed that the microstructure of the flow field has a significant effect on the tracer mixing process. The eccentric agitation can lead to the flow model change and the non-symmetric flow structure, which would possess an obvious superiority of mixing behavior. Moreover, the mixing rate and mixing efficiency are dependent on the shaft eccentricity and the stirrer off-bottom distance, showing the corresponding increase of the eccentricity with the off-bottom distance. The efficient mixing process of pseudoplastic fluid stirred by 6PBT impeller is obtained with the considerably low mixing energy per unit volume when the stirrer off-bottom distance, C, is T/3 and the eccentricity, e, is 0.2. The research results provide valuable references for the improvement of pseudoplastic fluid agitation technology.

Large eccentric strength increase using the Copenhagen Adduction exercise in football

DEFF Research Database (Denmark)

Ishøi, L; Sørensen, C N; Kaae, N M

2016-01-01

(control). EHAD, eccentric hip abduction strength (EHAB), and side-bridge endurance were measured using reliable test procedures at baseline and follow-up by a blinded tester. There was a significant interaction between group and time on EHAD, EHAB, and EHAD/EHAB ratio (P 

Eccentric and Isometric Hip Adduction Strength in Male Soccer Players With and Without Adductor-Related Groin Pain An Assessor-Blinded Comparison

DEFF Research Database (Denmark)

Thorborg, Kristian; Branci, Sonia; Nielsen, Peter Martin

2014-01-01

BACKGROUND: Adductor-related pain is the most common clinical finding in soccer players with groin pain and can be a long-standing problem affecting physical function and performance. Hip adductor weakness has been suggested to be associated with this clinical entity, although it has never been...... investigated. PURPOSE: To investigate whether isometric and eccentric hip strength are decreased in soccer players with adductor-related groin pain compared with asymptomatic soccer controls. The hypothesis was that players with adductor-related groin pain would have lower isometric and eccentric hip adduction...... strength than players without adductor-related groin pain. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Male elite and subelite players from 40 teams were contacted. In total, 28 soccer players with adductor-related groin pain and 16 soccer players without adductor-related groin pain...

Which one Enhances Muscular Performance in ACL Reconstructed Subjects

Science.gov (United States)

Harput, Gulcan; Ulusoy, Burak; Atay, Ahmet Ozgur; Baltacı, Gul

2014-01-01

Objectives: The aim of this study was to investigate the effects of functional knee brace and kinesiotaping on muscular performance in anterior cruciate ligament reconstructed subjects who reached return to sport phase of the rehabilitation. Methods: Twenty (17 males, 3 females, Age: 24.7±7.1 years, Body weight: 74.4±12.0 kg, Height: 177.9±6.5 cm, BMI: 23.9±3.6 kg/m2) subjects who underwent anterior cruciate ligament reconstruction by using hamstring tendon auto graft were included in this study. When the subjects reached the return to sports phase of rehabilitation which was 6th months after surgery, knee muscle strength, jump performance and balance tests were performed 3 times: bare, with knee brace and with kinesio taping. The order of the tests were randomized to eliminate the effects of fatigue and motor learning. Quadriceps and hamstring muscle strength was measured on an isokinetic dynamometer at 180 °/s and 60°/s angular velocities. Vertical Jump (VJ) and One Leg Hop Tests (OLHT) were used to assess jump performance. Star Excursion Balance Test (SEBT) with anterior, posteromedial and posterolateral reach distance was used to assess the dynamic balance. When all tests were performed, the subjects were asked under which test condition they felt more confident. Repeated measures of ANOVA was used to analyze the difference among three test conditions (bare, kinesiotaping, knee brace). Bonferroni post hoc test was used for pairwise comparison. Results: SEBT posteromedial (PM)and posterolateral (PL) reach distances were found significantly different among three test conditions(PM: F(2,38)=3.42,p=0.04), PL: F(2,38)=4.37,p=0.02). Kinesiotaping increased posteromedial reach distance (p=0.03). On the other hand, brace decreased posterolateral reach distance (p=0.04). VJ and OLHT performance were also found significantly different between three test conditions (VJ: F (2,38)=3.44,p=0.04, OLHT: (F(2,38)=4.04,p=0.02). Kinesio taping increased one leg hop distance

Effect of acute augmented feedback on between limb asymmetries and eccentric knee flexor strength during the Nordic hamstring exercise

Directory of Open Access Journals (Sweden)

Wade J. Chalker

2018-06-01

Full Text Available Background Hamstring strain injuries (HSI are one of the most prevalent and serious injuries affecting athletes, particularly those in team ball sports or track and field. Recent evidence demonstrates that eccentric knee flexor weakness and between limb asymmetries are possible risk factors for HSIs. While eccentric hamstring resistance training, e.g. the Nordic hamstring exercise (NHE significantly increases eccentric hamstring strength and reduces HSI risk, little research has examined whether between limb asymmetries can be reduced with training. As augmented feedback (AF can produce significant acute and chronic increases in muscular strength and reduce injury risk, one way to address the limitation in the eccentric hamstring training literature may be to provide athletes real-time visual AF of their NHE force outputs with the goal to minimise the between limb asymmetry. Methods Using a cross over study design, 44 injury free, male cricket players from two skill levels performed two NHE sessions on a testing device. The two NHE sessions were identical with the exception of AF, with the two groups randomised to perform the sessions with and without visual feedback of each limb’s force production in real-time. When performing the NHE with visual AF, the participants were provided with the following instructions to ‘reduce limb asymmetries as much as possible using the real-time visual force outputs displayed in front them’. Between limb asymmetries and mean peak force outputs were compared between the two feedback conditions (FB1 and FB2 using independent t-tests to ensure there was no carryover effect, and to determine any period and treatment effects. The magnitude of the differences in the force outputs were also examined using Cohen d effect size. Results There was a significant increase in mean peak force production when feedback was provided (mean difference, 21.7 N; 95% CI [0.2–42.3 N]; P = 0.048; d = 0.61 and no significant

Intra-subject variability in muscle activity and co-contraction during jumps and landings in children and adults

DEFF Research Database (Denmark)

Raffalt, P C; Alkjaer, T; Simonsen, E B

2017-01-01

-subject variability in the muscle activity. Co-contraction was quantified for two thigh muscle pairs and one plantar flexor/dorsiflexor muscle pair and group differences were assessed (two-way ANOVA). No significant differences were observed in the less eccentric demanding CMJ while significantly higher muscle...

Is there really an eccentric action of the hamstrings during the swing phase of high-speed running? Part II: Implications for exercise.

Science.gov (United States)

Van Hooren, Bas; Bosch, Frans

2017-12-01

We have previously argued that there may actually be no significant eccentric, but rather predominantly an isometric action of the hamstring muscle fibres during the swing phase of high-speed running when the attachment points of the hamstrings are moving apart. Based on this we suggested that isometric rather than eccentric exercises are a more specific way of conditioning the hamstrings for high-speed running. In this review we argue that some of the presumed beneficial adaptations following eccentric training may actually not be related to the eccentric muscle fibre action, but to other factors such as exercise intensity. Furthermore, we discuss several disadvantages associated with commonly used eccentric hamstring exercises. Subsequently, we argue that high-intensity isometric exercises in which the series elastic element stretches and recoils may be equally or even more effective at conditioning the hamstrings for high-speed running, since they also avoid some of the negative side effects associated with eccentric training. We provide several criteria that exercises should fulfil to effectively condition the hamstrings for high-speed running. Adherence to these criteria will guarantee specificity with regards to hamstrings functioning during running. Practical examples of isometric exercises that likely meet several criteria are provided.

Connective tissue regeneration in skeletal muscle after eccentric contraction-induced injury.

Science.gov (United States)

Mackey, Abigail L; Kjaer, Michael

2017-03-01

Human skeletal muscle has the potential to regenerate completely after injury induced under controlled experimental conditions. The events inside the myofibers as they undergo necrosis, followed closely by satellite cell-mediated myogenesis, have been mapped in detail. Much less is known about the adaptation throughout this process of both the connective tissue structures surrounding the myofibers and the fibroblasts, the cells responsible for synthesizing this connective tissue. However, the few studies investigating muscle connective tissue remodeling demonstrate a strong response that appears to be sustained for a long time after the major myofiber responses have subsided. While the use of electrical stimulation to induce eccentric contractions vs. voluntary eccentric contractions appears to lead to a greater extent of myofiber necrosis and regenerative response, this difference is not apparent when the muscle connective tissue responses are compared, although further work is required to confirm this. Pharmacological agents (growth hormone and angiotensin II type I receptor blockers) are considered in the context of accelerating the muscle connective tissue adaptation to loading. Cautioning against this, however, is the association between muscle matrix protein remodeling and protection against reinjury, which suggests that a (so far undefined) period of vulnerability to reinjury may exist during the remodeling phases. The role of individual muscle matrix components and their spatial interaction during adaptation to eccentric contractions is an unexplored field in human skeletal muscle and may provide insight into the optimal timing of rest vs. return to activity after muscle injury. Copyright © 2017 the American Physiological Society.

THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. III. A PAUCITY OF PROTO-HOT JUPITERS ON SUPER-ECCENTRIC ORBITS

International Nuclear Information System (INIS)

Dawson, Rebekah I.; Murray-Clay, Ruth A.; Johnson, John Asher

2015-01-01

Gas giant planets orbiting within 0.1 AU of their host stars are unlikely to have formed in situ and are evidence for planetary migration. It is debated whether the typical hot Jupiter smoothly migrated inward from its formation location through the proto-planetary disk, or was perturbed by another body onto a highly eccentric orbit, which tidal dissipation subsequently shrank and circularized during close stellar passages. Socrates and collaborators predicted that the latter model should produce a population of super-eccentric proto-hot Jupiters readily observable by Kepler. We find a paucity of such planets in the Kepler sample, which is inconsistent with the theoretical prediction with 96.9% confidence. Observational effects are unlikely to explain this discrepancy. We find that the fraction of hot Jupiters with an orbital period P > 3 days produced by the star-planet Kozai mechanism does not exceed (at two-sigma) 44%. Our results may indicate that disk migration is the dominant channel for producing hot Jupiters with P > 3 days. Alternatively, the typical hot Jupiter may have been perturbed to a high eccentricity by interactions with a planetary rather than stellar companion, and began tidal circularization much interior to 1 AU after multiple scatterings. A final alternative is that early in the tidal circularization process at high eccentricities tidal circularization occurs much more rapidly than later in the process at low eccentricities, although this is contrary to current tidal theories

Comparison of concentric and eccentric bench press repetitions to failure.

Science.gov (United States)

Kelly, Stephen B; Brown, Lee E; Hooker, Steven P; Swan, Pamela D; Buman, Matthew P; Alvar, Brent A; Black, Laurie E

2015-04-01

Eccentric muscle actions (ECC) are characterized by muscle lengthening, despite actin-myosin crossbridge formation. Muscles acting eccentrically are capable of producing higher levels of force compared with muscles acting concentrically. The purpose of this study was to determine whether ECC bench press yields greater strength than concentric (CON) as determined by 1 repetition maximum (1RM). Additionally, a comparison was made examining differences in the number of repetitions to failure at different relative intensities of 1RM. Thirty healthy men (age = 24.63 ± 5.6 years) were tested for 1RM in CON and ECC bench press and the number of repetitions completed at 60, 70, 80, and 90% 1RM. For CON repetitions, the weight was mechanically lowered to the chest, and the participant pressed it up until the elbows were fully extended. The ECC bench press consisted of lowering a barbell from a fully extended elbow position to the chest in a continuous controlled manner for 3 seconds as determined by electronic metronome. Paired t-tests showed that ECC 1RM (115.99 ± 31.08 kg) was significantly (p ≤ 0.05) greater than CON 1RM (93.56 ± 26.56 kg), and the number of repetitions completed at 90% 1RM was significantly (p ≤ 0.05) greater in ECC (7.67 ± 3.24) as compared with CON (4.57 ± 2.21). There were no significant differences in number of completed repetitions during CON and ECC bench press at 60, 70, and 80% 1RM. These data indicate that ECC actions yield increased force capabilities (∼120%) as compared with CON in the bench press and may be less prone to fatigue, especially at higher intensities. These differences suggest a need to develop unique strategies for training eccentrically.

Eccentricity samples: Implications on the potential and the velocity distribution

Directory of Open Access Journals (Sweden)

Cubarsi R.

2017-01-01

Full Text Available Planar and vertical epicycle frequencies and local angular velocity are related to the derivatives up to the second order of the local potential and can be used to test the shape of the potential from stellar disc samples. These samples show a more complex velocity distribution than halo stars and should provide a more realistic test. We assume an axisymmetric potential allowing a mixture of independent ellipsoidal velocity distributions, of separable or Staeckel form in cylindrical or spherical coordinates. We prove that values of local constants are not consistent with a potential separable in addition in cylindrical coordinates and with a spherically symmetric potential. The simplest potential that fits the local constants is used to show that the harmonical and non-harmonical terms of the potential are equally important. The same analysis is used to estimate the local constants. Two families of nested subsamples selected for decreasing planar and vertical eccentricities are used to borne out the relation between the mean squared planar and vertical eccentricities and the velocity dispersions of the subsamples. According to the first-order epicycle model, the radial and vertical velocity components provide accurate information on the planar and vertical epicycle frequencies. However, it is impossible to account for the asymmetric drift which introduces a systematic bias in estimation of the third constant. Under a more general model, when the asymmetric drift is taken into account, the rotation velocity dispersions together with their asymmetric drift provide the correct fit for the local angular velocity. The consistency of the results shows that this new method based on the distribution of eccentricities is worth using for kinematic stellar samples. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. No 176011: Dynamics and Kinematics of Celestial Bodies and Systems

Adding Fish Oil to Whey Protein, Leucine, and Carbohydrate Over a Six-Week Supplementation Period Attenuates Muscle Soreness Following Eccentric Exercise in Competitive Soccer Players.

Science.gov (United States)

Philpott, Jordan D; Donnelly, Chris; Walshe, Ian H; MacKinley, Elizabeth E; Dick, James; Galloway, Stuart D R; Tipton, Kevin D; Witard, Oliver C

2018-01-01

Soccer players often experience eccentric exercise-induced muscle damage given the physical demands of soccer match-play. Since long chain n-3 polyunsaturated fatty acids (n-3PUFA) enhance muscle sensitivity to protein supplementation, dietary supplementation with a combination of fish oil-derived n-3PUFA, protein, and carbohydrate may promote exercise recovery. This study examined the influence of adding n-3PUFA to a whey protein, leucine, and carbohydrate containing beverage over a six-week supplementation period on physiological markers of recovery measured over three days following eccentric exercise. Competitive soccer players were assigned to one of three conditions (2 × 200 mL): a fish oil supplement beverage (FO; n = 10) that contained n-3PUFA (1100 mg DHA/EPA-approximately 550 mg DHA, 550 mg EPA), whey protein (15 g), leucine (1.8 g), and carbohydrate (20 g); a protein supplement beverage (PRO; n = 10) that contained whey protein (15 g), leucine (1.8 g), and carbohydrate (20 g); and a carbohydrate supplement beverage (CHO; n = 10) that contained carbohydrate (24 g). Eccentric exercise consisted of unilateral knee extension/flexion contractions on both legs separately. Maximal force production was impaired by 22% during the 72-hour recovery period following eccentric exercise (p recovery, was less in FO (1948 ± 1091 mm × 72 h) than PRO (4640 ± 2654 mm × 72 h, p soccer performance, or blood c-reactive protein concentrations were observed between groups. In conclusion, the addition of n-3PUFA to a beverage containing whey protein, leucine, and carbohydrate ameliorates the increase in muscle soreness and blood concentrations of creatine kinase following eccentric exercise in competitive soccer players.

Eccentricity in Images of Circular and Spherical Targets and its Impact to 3D Object Reconstruction

Directory of Open Access Journals (Sweden)

T. Luhmann

2014-06-01

Full Text Available This paper discusses a feature of projective geometry which causes eccentricity in the image measurement of circular and spherical targets. While it is commonly known that flat circular targets can have a significant displacement of the elliptical image centre with respect to the true imaged circle centre, it can also be shown that the a similar effect exists for spherical targets. Both types of targets are imaged with an elliptical contour. As a result, if measurement methods based on ellipses are used to detect the target (e.g. best-fit ellipses, the calculated ellipse centre does not correspond to the desired target centre in 3D space. This paper firstly discusses the use and measurement of circular and spherical targets. It then describes the geometrical projection model in order to demonstrate the eccentricity in image space. Based on numerical simulations, the eccentricity in the image is further quantified and investigated. Finally, the resulting effect in 3D space is estimated for stereo and multi-image intersections. It can be stated that the eccentricity is larger than usually assumed, and must be compensated for high-accuracy applications. Spherical targets do not show better results than circular targets. The paper is an updated version of Luhmann (2014 new experimental investigations on the effect of length measurement errors.

Estimation of the measurement error of eccentrically installed orifice plates

Energy Technology Data Exchange (ETDEWEB)

Barton, Neil; Hodgkinson, Edwin; Reader-Harris, Michael

2005-07-01

The presentation discusses methods for simulation and estimation of flow measurement errors. The main conclusions are: Computational Fluid Dynamics (CFD) simulation methods and published test measurements have been used to estimate the error of a metering system over a period when its orifice plates were eccentric and when leaking O-rings allowed some gas to bypass the meter. It was found that plate eccentricity effects would result in errors of between -2% and -3% for individual meters. Validation against test data suggests that these estimates of error should be within 1% of the actual error, but it is unclear whether the simulations over-estimate or under-estimate the error. Simulations were also run to assess how leakage at the periphery affects the metering error. Various alternative leakage scenarios were modelled and it was found that the leakage rate has an effect on the error, but that the leakage distribution does not. Correction factors, based on the CFD results, were then used to predict the system's mis-measurement over a three-year period (tk)

The Effects of Eccentric, Velocity-Based Training on Strength and Power in Collegiate Athletes.

Science.gov (United States)

Dolezal, Samantha M; Frese, Derek L; Llewellyn, Tamra L

2016-01-01

The purpose of this study was to determine if combining velocity-based training with eccentric focus (VEB) and velocity-based training (VBT) results in power and strength gains. Nineteen men and women collegiate track and field athletes participated in this study. The subjects completed a 12-week intervention with either a VEB program or a VBT program. To determine the effectiveness of each program, the subjects completed four exercise tests before and after the training period: vertical jump, medicine ball put test, 1RM projected bench press and 1RM projected squat. There were no significant differences between the VBT results and the VEB results. However, there were significant improvements between the pre-test and post-test measures for each group. There were increases in 1RM projected squat for VEB men, VBT men, and VBT women. There were also significant improvements in the VEB male vertical jump and medicine ball put test pre- to post-intervention. For track and field athletes, both programs may result in strength and power gains, however, the results cannot be used to conclude that one resistance training program is superior.

Higher order mode excitation in eccentric active nano-particles for tailoring of the near-field radiation

DEFF Research Database (Denmark)

Thorsen, R. O.; Arslanagic, Samel

2015-01-01

We examine the excitation of resonant modes inside eccentrically layered cylindrical active nano-particles. The nano-particle is a three-layer structure comprised of a silica core, a free-space middle layer, and an outer shell of silver. It is shown that a concentric configuration, initially desi...... of the gain constant, is shown to be controlled by the direction of the core displacement. The present eccentric active nano-particles may provide alternative strategies for directive near-field radiation relative to the existing designs....

Effects of the Eccentricity of a Perturbing Third Body on the Orbital Correction Maneuvers of a Spacecraft

Directory of Open Access Journals (Sweden)

R. C. Domingos

2014-01-01

Full Text Available The fuel consumption required by the orbital maneuvers when correcting perturbations on the orbit of a spacecraft due to a perturbing body was estimated. The main goals are the measurement of the influence of the eccentricity of the perturbing body on the fuel consumption required by the station keeping maneuvers and the validation of the averaged methods when applied to the problem of predicting orbital maneuvers. To study the evolution of the orbits, the restricted elliptic three-body problem and the single- and double-averaged models are used. Maneuvers are made by using impulsive and low thrust maneuvers. The results indicated that the averaged models are good to make predictions for the orbital maneuvers when the spacecraft is in a high inclined orbit. The eccentricity of the perturbing body plays an important role in increasing the effects of the perturbation and the fuel consumption required for the station keeping maneuvers. It is shown that the use of more frequent maneuvers decreases the annual cost of the station keeping to correct the orbit of a spacecraft. An example of an eccentric planetary system of importance to apply the present study is the dwarf planet Haumea and its moons, one of them in an eccentric orbit.

Reliability of a two-wavelength autofluorescence technique by Heidelberg Spectralis to measure macular pigment optical density in Asian subjects.

Science.gov (United States)

Obana, Akira; Gellermann, Werner; Gohto, Yuko; Seto, Takahiko; Sasano, Hiroyuki; Tanito, Masaki; Okazaki, Shigetoshi

2018-03-01

This study evaluates the accuracy of an objective two-wavelength fundus autofluorescence technique for the purpose of measuring the macular pigment optical density (MPOD) in Asian pigmented eyes. Potential differences between MPOD values obtained via autofluorescence technique and subjective heterochromatic photometry (HFP) were examined. Inter-examiner reproducibility between three examiners and test-retest reliability over five time points were also explored. Subjects were 27 healthy Japanese volunteers aged 24 to 58 (mean ± standard deviation, 40.2 ± 9.0) years. An MPOD module of the Spectralis MultiColor instrument configuration (Spectralis-MP) was used for the autofluorescence technique, and a Macular Metrics Densitometer (MM) was used for HFP. The mean MPOD values at 0.25° and 0.5° eccentricities using the Spectralis-MP were 0.51 ± 0.12 and 0.48 ± 0.13, respectively. In comparison, the MM based values were 0.72 ± 0.23 and 0.61 ± 0.25, respectively. High correlations between the Spectralis-MP and MM instrument were found (Pearson's correlation coefficients of 0.73 and 0.87 at 0.25° and 0.5° eccentricities, respectively), but there was a systematic bias: the MPOD values by MM method were significantly higher than those by Spectralis-MP at 0.25° eccentricity. High inter-examiner reproducibility and test-retest reliability were found for MM measurements at 0.5° eccentricity, but not at 0.25°. The Spectralis-MP showed less inter-examiner and test-retest variability than the MM instrument at 0.25° and 0.5° eccentricities. We conclude that the Spectralis-MP, given its high agreement with the HFP method and due to its higher reproducibility and reliability, is well suited for clinical measurements of MPOD levels in Asian pigmented eyes. Copyright © 2018. Published by Elsevier Ltd.

DAY-SIDE z'-BAND EMISSION AND ECCENTRICITY OF WASP-12b

International Nuclear Information System (INIS)

Lopez-Morales, Mercedes; Rogers, Justin C.; Coughlin, Jeffrey L.; Sing, David K.; Burrows, Adam; Spiegel, David S.; Apai, Daniel; Adams, Elisabeth R.

2010-01-01

We report the detection of the eclipse of the very hot Jupiter WASP-12b via z'-band time-series photometry obtained with the 3.5 m Astrophysical Research Consortium telescope at Apache Point Observatory. We measure a decrease in flux of 0.082% ± 0.015% during the passage of the planet behind the star. That planetary flux is equally well reproduced by atmospheric models with and without extra absorbers, and blackbody models with f ≥ 0.585 ± 0.080. It is therefore necessary to measure the planet at other wavelengths to further constrain its atmospheric properties. The eclipse appears centered at phase φ = 0.5100 +0.0072 -0.0061 , consistent with an orbital eccentricity of |ecos ω| = 0.016 +0.011 -0.009 (see note at the end of Section 4). If the orbit of the planet is indeed eccentric, the large radius of WASP-12b can be explained by tidal heating.

The Effects of Spatial Endogenous Pre-cueing across Eccentricities

OpenAIRE

Feng, Jing; Spence, Ian

2017-01-01

Frequently, we use expectations about likely locations of a target to guide the allocation of our attention. Despite the importance of this attentional process in everyday tasks, examination of pre-cueing effects on attention, particularly endogenous pre-cueing effects, has been relatively little explored outside an eccentricity of 20°. Given the visual field has functional subdivisions that attentional processes can differ significantly among the foveal, perifoveal, and more peripheral areas...

The Effect of Single Portion Glutamine Supplement Consumption on Injury Indices of Muscle After Eccentric Resistance Exercise

OpenAIRE

Azadeh Najarzadeh; Hadi Atarod; Hasan Mozaffari-Khosravi; Ali Dehghani; Foad Asjodi

2015-01-01

Abstract Background: Delayed muscular soreness after resistance exercises or eccentric trainings is probably because of muscle damage and injury. Nutrition by playing a crucial role in both protein synthesize and catabolism can influence the extent of muscle injury. The objective of this study was to assess the effect of single portion of Glutamine supplement consumption on injury indices of muscle after a session eccentric resistance exercise. Materials and Methods: this study used a ...

On power flow suppression in straight elastic pipes by use of equally spaced eccentric inertial attachments

DEFF Research Database (Denmark)

Sorokin, Sergey; Holst-Jensen, Ole

2012-01-01

The paper addresses the power flow suppression in an elastic beam of the tubular cross section (a pipe) at relatively low excitation frequencies by deploying a small number of equally spaced inertial attachments. The methodology of boundary integral equations is used to obtain an exact solution...... of the problem in vibrations of this structure. The power flow analysis in a pipe with and without equally spaced eccentric inertial attachments is performed and the effect of suppression of the energy transmission is demonstrated theoretically. These results are put in the context of predictions from...

On the divergence of triangular and eccentric spherical sums of double Fourier series

Energy Technology Data Exchange (ETDEWEB)

Karagulyan, G A [Institute of Mathematics, National Academy of Sciences of Armenia, Yerevan (Armenia)

2016-01-31

We construct a continuous function on the torus with almost everywhere divergent triangular sums of double Fourier series. We also prove an analogous theorem for eccentric spherical sums. Bibliography: 14 titles.

On the divergence of triangular and eccentric spherical sums of double Fourier series

International Nuclear Information System (INIS)

Karagulyan, G A

2016-01-01

We construct a continuous function on the torus with almost everywhere divergent triangular sums of double Fourier series. We also prove an analogous theorem for eccentric spherical sums. Bibliography: 14 titles

Effects of concentric and repeated eccentric exercise on muscle damage and calpain-calpastatin gene expression in human skeletal muscle

DEFF Research Database (Denmark)

Vissing, K.; Overgaard, K.; Nedergaard, A.

2008-01-01

, and was compared to a control-group (n = 6). Muscle strength and soreness and plasma creatine kinase and myoglobin were measured before and during 7 days following exercise bouts. Muscle biopsies were collected from m. vastus lateralis of both legs prior to and at 3, 24 h and 7 days after exercise and quantified...... for muscle Ca2+-content and mRNA levels for calpain isoforms and calpastatin. Exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P ... eccentric exercise bout (P muscle Ca2+-content did not differ between interventions. mRNA levels for calpain 2 and calpastatin were upregulated exclusively by eccentric exercise 24 h post-exercise (P

Eccentric and isometric shoulder rotator cuff strength testing using a hand-held dynamometer: reference values for overhead athletes.

Science.gov (United States)

Cools, Ann M J; Vanderstukken, Fran; Vereecken, Frédéric; Duprez, Mattias; Heyman, Karel; Goethals, Nick; Johansson, Fredrik

2016-12-01

In order to provide science-based guidelines for injury prevention or return to play, regular measurement of isometric and eccentric internal (IR) and external (ER) rotator strength is warranted in overhead athletes. However, up to date, no normative database exists regarding these values, when measured with a hand-held dynamometer. Therefore, the purpose of the study was to provide a normative database on isometric and eccentric rotator cuff (RC) strength values in a sample of overhead athletes, and to discuss gender, age and sports differences. A HHD was used to measure RC strength in 201 overhead athletes between 18 and 50 years old from three different sports disciplines: tennis, volleyball and handball. Isometric as well as eccentric strength was measured in different shoulder positions. Outcome variables of interest were isometric ER and IR strength, eccentric ER strength, and intermuscular strength ratios ER/IR. Our results show significant side, gender and sports discipline differences in the isometric and eccentric RC strength. However, when normalized to body weight, gender differences often are absent. In general, strength differences are in favour of the dominant side, the male athletes and handball. Intermuscular ER/IR ratios showed gender, sports, and side differences. This normative database is necessary to help the clinician in the evaluation of RC strength in healthy and injured overhead athletes. In view of the preventive screening and return-to-play decisions in overhead athletes, normalization to body weight and calculating intermuscular ratios are key points in this evaluation. Diagnostic study, Level III.

A Note on Eccentricities within a Single n-Layered Obstacle and their Influence on Time Harmonic SH Waves

International Nuclear Information System (INIS)

Weber, Wolfgang; Zastrau, Bernd W.

2010-01-01

In this contribution some aspects of SH wave scattering due to a single eccentric n-layered obstacle are being looked at. Herewith, the basis solution is derived analytically for an elliptic inclusion as it occurs in civil engineering practice e. g. within textile reinforced concrete. Hence, (modified) MATHIEUfunctions have to be evaluated. Later on, the degenerate case of an eccentric circular obstacle is dealt with.

Analysis of radial runout for symmetric and asymmetric HDD spindle motors with rotor eccentricity

International Nuclear Information System (INIS)

Kim, T.-J.; Kim, K.-T.; Hwang, S.-M.; Lee, S.-B.; Park, N.-G.

2001-01-01

Radial runout of disk drive spindle is one of the major limiting factors in achieving higher track densities in hard disk drives. Mechanical, magnetic and their coupled origins, such as unbalanced mass, reaction forces and magnetic forces, introduce radial runout of spindle motors. In this paper, radial magnetic forces are calculated with respect to the various rotor eccentricities using analytic method. Based on the results of the radial magnetic forces, the radial runout of the spindle motor is analyzed using finite element and transfer matrices. Results show that an asymmetric motor has a worse performance on unbalanced magnetic forces and radial runout when mechanical and magnetic coupling exists

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b

Science.gov (United States)

Winn, Joshua N.; Howard, Andrew W.; Johnson, John A.; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colon, Knicole D.; Reyes, Francisco; Nortmann, Lisa;

Recent advances in the understanding of the repeated bout effect: the protective effect against muscle damage from a single bout of eccentric exercise.

Science.gov (United States)

McHugh, Malachy P

2003-04-01

The repeated bout effect refers to the adaptation whereby a single bout of eccentric exercise protects against muscle damage from subsequent eccentric bouts. While the mechanism for this adaptation is poorly understood there have been significant recent advances in the understanding of this phenomenon. The purpose of this review is to provide an update on previously proposed theories and address new theories that have been advanced. The potential adaptations have been categorized as neural, mechanical and cellular. There is some evidence to suggest that the repeated bout effect is associated with a shift toward greater recruitment of slow twitch motor units. However, the repeated bout effect has been demonstrated with electrically stimulated contractions, indicating that a peripheral, non-neural adaptation predominates. With respect to mechanical adaptations there is evidence that both dynamic and passive muscle stiffness increase with eccentric training but there are no studies on passive or dynamic stiffness adaptations to a single eccentric bout. The role of the cytoskeleton in regulating dynamic stiffness is a possible area for future research. With respect to cellular adaptations there is evidence of longitudinal addition of sarcomeres and adaptations in the inflammatory response following an initial bout of eccentric exercise. Addition of sarcomeres is thought to reduce sarcomere strain during eccentric contractions thereby avoiding sarcomere disruption. Inflammatory adaptations are thought to limit the proliferation of damage that typically occurs in the days following eccentric exercise. In conclusion, there have been significant advances in the understanding of the repeated bout effect, however, a unified theory explaining the mechanism or mechanisms for this protective adaptation remains elusive.

Comparison of the Force-, Velocity- and Power-Time Curves Between the Concentric-Only and Eccentric-Concentric Bench Press Exercises.

Science.gov (United States)

Pérez-Castilla, Alejandro; Comfort, Paul; McMahon, John J; Pestaña-Melero, Francisco Luis; García-Ramos, Amador

2018-01-17

The aim of this study was to compare the temporal and mechanical variables between the concentric-only and eccentric-concentric bench press (BP) variants. Twenty-one men (age: 22.0±4.2 years, body mass: 73.4±7.7 kg, height: 177.2±8.0 cm; one-repetition maximum [1RM]: 1.12±0.12 kg⋅kg) were evaluated during the concentric-only and eccentric-concentric BP variants using 80% 1RM. Temporal (concentric phase duration, propulsive phase duration, and time to reach the maximum values of force, velocity, and power) and mechanical variables (force, velocity, and power), determined using a linear velocity transducer, were compared between both BP variants. All temporal variables were significantly lower during the eccentric-concentric BP compared to the concentric-only BP (P velocity and power were significantly higher for the eccentric-concentric BP compared to the concentric-only BP (all P velocity (ES: 0.40) and power (ES: 0.41). The stretch-shortening cycle (i.e., eccentric-concentric BP) mainly enhanced force production at the early portion of the concentric phase, but this potentiation effect gradually reduced over the latter part of the movement. Finally, force was higher for the concentric-only BP during 49% of the concentric phase duration. These results suggest that both BP variants should be included during resistance training programs in order to optimize force output at different points of the concentric phase.

Black Hole Mergers in Galactic Nuclei Induced by the Eccentric Kozai–Lidov Effect

Science.gov (United States)

Hoang, Bao-Minh; Naoz, Smadar; Kocsis, Bence; Rasio, Frederic A.; Dosopoulou, Fani

2018-04-01

Nuclear star clusters around a central massive black hole (MBH) are expected to be abundant in stellar black hole (BH) remnants and BH–BH binaries. These binaries form a hierarchical triple system with the central MBH, and gravitational perturbations from the MBH can cause high-eccentricity excitation in the BH–BH binary orbit. During this process, the eccentricity may approach unity, and the pericenter distance may become sufficiently small so that gravitational-wave emission drives the BH–BH binary to merge. In this work, we construct a simple proof-of-concept model for this process, and specifically, we study the eccentric Kozai–Lidov mechanism in unequal-mass, soft BH–BH binaries. Our model is based on a set of Monte Carlo simulations for BH–BH binaries in galactic nuclei, taking into account quadrupole- and octupole-level secular perturbations, general relativistic precession, and gravitational-wave emission. For a typical steady-state number of BH–BH binaries, our model predicts a total merger rate of ∼1–3 {Gpc} ‑3 {yr} ‑1, depending on the assumed density profile in the nucleus. Thus, our mechanism could potentially compete with other dynamical formation processes for merging BH–BH binaries, such as the interactions of stellar BHs in globular clusters or in nuclear star clusters without an MBH.

TOWARD A DETERMINISTIC MODEL OF PLANETARY FORMATION. VII. ECCENTRICITY DISTRIBUTION OF GAS GIANTS

International Nuclear Information System (INIS)

Ida, S.; Lin, D. N. C.; Nagasawa, M.

2013-01-01

The ubiquity of planets and diversity of planetary systems reveal that planet formation encompasses many complex and competing processes. In this series of papers, we develop and upgrade a population synthesis model as a tool to identify the dominant physical effects and to calibrate the range of physical conditions. Recent planet searches have led to the discovery of many multiple-planet systems. Any theoretical models of their origins must take into account dynamical interactions between emerging protoplanets. Here, we introduce a prescription to approximate the close encounters between multiple planets. We apply this method to simulate the growth, migration, and dynamical interaction of planetary systems. Our models show that in relatively massive disks, several gas giants and rocky/icy planets emerge, migrate, and undergo dynamical instability. Secular perturbation between planets leads to orbital crossings, eccentricity excitation, and planetary ejection. In disks with modest masses, two or less gas giants form with multiple super-Earths. Orbital stability in these systems is generally maintained and they retain the kinematic structure after gas in their natal disks is depleted. These results reproduce the observed planetary mass-eccentricity and semimajor axis-eccentricity correlations. They also suggest that emerging gas giants can scatter residual cores to the outer disk regions. Subsequent in situ gas accretion onto these cores can lead to the formation of distant (∼> 30 AU) gas giants with nearly circular orbits

An improved model of induction motors for diagnosis purposes - Slot skewing effect and air-gap eccentricity faults

Energy Technology Data Exchange (ETDEWEB)

Ghoggal, A.; Zouzou, S.E.; Sahraoui, M. [Laboratoire de genie electrique de Biskra, Departement d' electrotechnique, Universite Mohamed Khider, BP 145, Biskra (Algeria); Razik, H. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, Universite Henri Poincare, Faculte des Sciences et Techniques, BP 239, F-54506 Vandoeuvre-les-Nancy (France); Khezzar, A. [Laboratoire d' Electrotechnique de Constantine, Universite Mentouri, Constantine (Algeria)

2009-05-15

This paper describes an improved method for the modeling of axial and radial eccentricities in induction motors (IM). The model is based on an extension of the modified winding function approach (MWFA) which allows for all harmonics of the magnetomotive force (MMF) to be taken into account. It is shown that a plane view of IM gets easily the motor inductances and reduces considerably the calculation process. The described technique includes accurately the slot skewing effect and leads to pure analytical expressions of the inductances in case of radial eccentricity. In order to model the static, dynamic or mixed axial eccentricity, three suitable alternatives are explained. Unlike the previous proposals, the discussed alternatives take into account all the harmonics of the inverse of air-gap function without any development in Fourier series. Simulation results as well as experimental verifications prove the usefulness and the effectiveness of the proposed model. (author)

An improved model of induction motors for diagnosis purposes - Slot skewing effect and air-gap eccentricity faults

International Nuclear Information System (INIS)

Ghoggal, A.; Zouzou, S.E.; Razik, H.; Sahraoui, M.; Khezzar, A.

2009-01-01

This paper describes an improved method for the modeling of axial and radial eccentricities in induction motors (IM). The model is based on an extension of the modified winding function approach (MWFA) which allows for all harmonics of the magnetomotive force (MMF) to be taken into account. It is shown that a plane view of IM gets easily the motor inductances and reduces considerably the calculation process. The described technique includes accurately the slot skewing effect and leads to pure analytical expressions of the inductances in case of radial eccentricity. In order to model the static, dynamic or mixed axial eccentricity, three suitable alternatives are explained. Unlike the previous proposals, the discussed alternatives take into account all the harmonics of the inverse of air-gap function without any development in Fourier series. Simulation results as well as experimental verifications prove the usefulness and the effectiveness of the proposed model.

Effect of eccentric isokinetic strengthening in the rehabilitation of patients with knee osteoarthritis: Isogo, a randomized trial

Science.gov (United States)

2014-01-01

Background Femorotibial knee osteoarthritis is associated with muscle weakness in the lower limbs, particularly in the quadriceps, which results in disease progression. The interest of having muscular strengthening as part of the therapeutic arsenal for the medical treatment of knee osteoarthritis is now well established. The functional disability induced by knee osteoarthritis manifests itself principally when walking, notably downhill, during which the muscles are called upon to contract eccentrically. We can therefore think that eccentric muscular strengthening could bring a functional benefit that is superior to concentric muscular strengthening. Methods/Design This is a prospective, randomized, bicenter, parallel-group, international study. Eighty patients aged from 40 to 75 years old, suffering from medical-stage knee osteoarthritis, will undertake 6 weeks of isokinetic muscular strengthening. Randomization determines the mode of muscular strengthening: either exclusively eccentric or exclusively concentric. The principal objective is to demonstrate the superiority of the improvement in the quadriceps isokinetic torque after isokinetic muscular strengthening by the eccentric mode compared to the concentric mode. The following parameters are also evaluated: the variations in the level of pain, the parameters of walking (maximum speed over 10 and 200 meters, analysis on a computerized Gaitrite™ treadmill), static equilibrium (on a FUSYO™ force platform), and the functional status of the patient using the Western Ontario and MacMaster Universities osteoarthritis index (WOMAC) questionnaire after the strengthening period and at 6 months. Discussion A better knowledge of the most effective mode of muscular strengthening is needed to optimize the functional benefits to the patients. In case of superiority in terms of efficacy of the eccentric mode, the latter could be given priority in the rehabilitation treatment of knee osteoarthritis patients. Trial

António Reis and Margarida Cordeiro, eccentric filmmakers

Directory of Open Access Journals (Sweden)

Lucas Tavares Neves

2016-02-01

Full Text Available The international symposium "António Reis and Margarida Cordeiro, eccentric filmmakers" took place in Paris between the 3rd and the 4th of June, 2015. Speakers exchanged on the political, social and poetical aspects of the duo's cinematography, as well as on the reverberations of titles such as Jaime (1974 and Trás-os-montes (1976 on the Portuguese filmic landscape of the decades that followed.

Various Indices for Diagnosis of Air-gap Eccentricity Fault in Induction Motor-A Review

Science.gov (United States)

Nikhil; Mathew, Lini, Dr.; Sharma, Amandeep

2018-03-01

From the past few years, research has gained an ardent pace in the field of fault detection and diagnosis in induction motors. In the current scenario, software is being introduced with diagnostic features to improve stability and reliability in fault diagnostic techniques. Human involvement in decision making for fault detection is slowly being replaced by Artificial Intelligence techniques. In this paper, a brief introduction of eccentricity fault is presented along with their causes and effects on the health of induction motors. Various indices used to detect eccentricity are being introduced along with their boundary conditions and their future scope of research. At last, merits and demerits of all indices are discussed and a comparison is made between them.

Effect of load eccentricity on the buckling of thin-walled laminated C-columns

Science.gov (United States)

Wysmulski, Pawel; Teter, Andrzej; Debski, Hubert

2018-01-01

The study investigates the behaviour of short, thin-walled laminated C-columns under eccentric compression. The tested columns are simple-supported. The effect of load inaccuracy on the critical and post-critical (local buckling) states is examined. A numerical analysis by the finite element method and experimental tests on a test stand are performed. The samples were produced from a carbon-epoxy prepreg by the autoclave technique. The experimental tests rest on the assumption that compressive loads are 1.5 higher than the theoretical critical force. Numerical modelling is performed using the commercial software package ABAQUS®. The critical load is determined by solving an eigen problem using the Subspace algorithm. The experimental critical loads are determined based on post-buckling paths. The numerical and experimental results show high agreement, thus demonstrating a significant effect of load inaccuracy on the critical load corresponding to the column's local buckling.

An investigation into the immediate effects of pelvic taping on hamstring eccentric force in an elite male sprinter - A case report.

Science.gov (United States)

Macdonald, Ben

2017-11-01

Hamstring Injuries commonly cause missed training and competition time in elite sports. Injury surveillance studies have demonstrated high injury and re-injury rates, which have not improved across sports despite screening and prevention programmes being commonplace. The most commonly suggested intervention for hamstring prevention and rehabilitation is eccentric strength assessment and training. This case study describes the management of an elite sprinter with a history of hamstring injury. A multi-variate screening process based around lumbar-pelvic dysfunction and hamstring strength assessment using the Nordbord is employed. The effect of external pelvic compression using a taping technique, on eccentric hamstring strength is evaluated. A persistent eccentric strength asymmetry of 17% was recorded as well as lumbar-pelvic control deficits. Pelvic taping appears to improve load transfer capability across the pelvis, resulting in correction of eccentric strength asymmetry. Screening strategies and interventions to prevent hamstring injury have failed to consistently improve injury rates across various sports. In this case study external pelvic compression resulted in normalising eccentric strength deficits assessed using the Nordbord. The inclusion of lumbar-pelvic motor control assessment, in relation to hamstring strength and function, as part of a multi-variate screening strategy requires further research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performing in-feed type centerless grinding process on a surface grinder

International Nuclear Information System (INIS)

Xu, W.; Wu, Y.; Sato, T.; Lin, W.

2011-01-01

In our previous study, a new centerless grinding method using surface grinder was proposed. In this method, centerless grinding operations are performed by installing a compact centerless grinding unit, consisting mainly of an ultrasonic elliptic-vibration shoe, a blade and their respective holders, on the worktable of a surface grinder. During grinding, the cylindrical workpiece is held on the ultrasonic shoe and the blade, and its rotational motion is controlled by the elliptic motion of the shoe end-face. An actual unit had been produced and its performance in tangential-feed type centerless grinding using a surface grinder had been confirmed in the previous workd. In this paper, the performance of the grinding unit in in-feed centerless grinding operation was confirmed, and the effects of the main process parameter, i.e., eccentric angle, on the workpiece roundness was investigated experimentally. The obtained results showed that: (1) the centerless grinding unit performed well in in-feed type centerless grinding; (2) the eccentric angle affects roundness significantly, and its optimal angle is 6 deg.; (3) the workpiece roundness can be further improved by varying the eccentric angle during grinding, and the final roundness reached 0.65 μm after grinding as the eccentric angle varied from 9 deg. to 6 deg. and to 3 deg.

A Novel Approach for Eccentricity Fault Detection in Squirrel Cage Induction Motors

Directory of Open Access Journals (Sweden)

Mehdi Ahmadi

2013-01-01

Full Text Available In this paper, static eccentricity fault detection in induction motors is studied. Two dimensional finite element method (2D-FEM is used for faultless and eccentric condition modeling in induction motors. Also current and speed signals are compared in two experimental and simulation cases for model validating. For fault detection, fast Fourier transform is used at first. In this method, high order harmonics with small amplitude can alarms the fault occurrence. For this reason, the fault detection process is difficult.To overcome these drawbacks, it is suggested that two test coils contrive around the air-gap. So, any changes in air-gap can be detected easily. Moreover this test coils are used in open circuit case. So, these test coils do not effect on motor dynamics. Also, the results show that modulated voltage can be alarm the fault occurrence, type and percent well.

Temperature distribution on fuel rods: a study on the effect of eccentricity in the position of UO2 pellets

International Nuclear Information System (INIS)

Gaspar Junior, Joao Carlos Aguiar

2010-01-01

This work proposes the development of a method of solving equations of heat transfer applied in fuel rods using the finite element method, in order to evaluate the performance and safety of the nuclear system. Was prepared in a Fortran program to evaluate the equations governing the problem, the boundary conditions and apply the properties of materials on a steady state. This program uses the mesh generation input and graphical output generated by the program GID. The method was validated against the analytical solution found in the book Todreas and Kazimi with error less than 0.2% and with respect to the improved analytical solution of Nijsing for axisymmetry rod and eccentricity rod with error less than a 3.6%. Applications have been developed with the use of correlations for properties with the temperature dependence of resolution axisymmetry rod and the resolution of a rod with eccentricity. The method developed, should it be implemented, would allow the assessment of fuel rods in the given situations and other scenarios, as well as adding a tool of substantial value in the analysis of rods. (author)

Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

International Nuclear Information System (INIS)

Schuhbaeck, Annika; Weingartner, Christina; Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed; Rixe, Johannes; Nef, Holger; Schneider, Christian; Lell, Michael; Uder, Michael; Ensminger, Stephan; Feyrer, Richard; Weyand, Michael; Achenbach, Stephan

2015-01-01

Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification

New binary pulsar in a highy eccentric orbit

International Nuclear Information System (INIS)

Stokes, G.H.; Taylor, J.H.; Dewey, R.J.

1985-01-01

We report the discovery of PSR 2303+46, the fifth radio pulsar known to be in a gravitationally bound orbit around another star. The pulsar period (1.066 s) and the orbital eccentricity (0.658) are the largest amount the five binary systems, while the orbital period (12./sup d/34) lies near the middle of the range. Evolutionary considerations suggest strongly that the companion is another neutron star. The general relativistic precession of periastron should be observable within 1 or 2 yr and, when measured, will specify the total mass of the two stars

3-D NUMERICAL STUDY AND COMPARISON OF ECCENTRIC AND CONCENTRIC ANNULAR-FINNED TUBE HEAT EXCHANGERS

Directory of Open Access Journals (Sweden)

FAROUK TAHROUR

2015-11-01

Full Text Available The use of 3-D computational fluid dynamics (CFD is proposed to simulate the conjugate conduction-convection of heat transfer problems in eccentric annularfinned tube heat exchangers. The numerical simulation results allow us to evaluate the heat transfer coefficient over fin surfaces, the fin efficiency and the pressure drop. The aim of the present paper is to determine the optimum tube position in the circular fin that maximizes heat dissipation and minimizes pressure drop. In addition, this study analyzes the effects of fin spacing and fin tube diameter on heat transfer and flow characteristics for a range of Reynolds numbers, 4500≤Re≤22500. A satisfactory qualitative and quantitative agreement was obtained between the numerical predictions and the results published in the literature. For small fin spacings, the eccentric annular finned tube is more efficient than the concentric one. Among the cases examined, the average heat transfer coefficient of the eccentric annular-finned tube, for a tube shift St =12 mm and a Reynolds number Re = 9923, was 7.61% greater than that of the concentric one. This gain is associated with a 43.09% reduction in pressure drop.

Eccentric Voices and the Representation of Vocal Virtuosity in Fiction: James McCourt’s Mawrdew Czgowchwz

Directory of Open Access Journals (Sweden)

Marcin Stawiarski

2016-06-01

Full Text Available This paper examines the representation of vocal virtuosity in fiction. It focuses on the concept of voice as it is represented in a work of fiction through musical eccentricity. The paper centres on James McCourt’s Mawrdew Czgowchwz (1975. James McCourt’s novel tells the story of an opera singer, Mawrdew Czgowchwz. In the novel, the voice is related to extravagance and fanaticism, so that it relates to violence and conflict. In McCourt’s novel, the stylistic features of the text show a hyperbolic use of language resorting to Rabelaisian lists, foreign vocabulary, neologisms, or nonce-words, which create tongue-twister cornucopia effects of linguistic musicality. The paper aims to demonstrate that (a the mode of eccentricity is a fundamental mode of representing music in literature; (b eccentricity rubs off on the very structure of the text, so that it leads to singular forms of operatic musicalization of fiction and musicalized writing; (c the voice ends up turning into a fetish object.

Forging of eccentric co-extruded Al-Mg compounds and analysis of the interface strength

International Nuclear Information System (INIS)

Förster, W; Binotsch, C; Awiszus, B; Lehmann, T; Müller, J; Kirbach, C; Stockmann, M; Ihlemann, J

2016-01-01

Within the subproject B3 of the Collaborative Research Center 692 it has been shown that Al-Mg compounds with a good bonding quality can be produced by hydrostatic coextrusion. During processing by forging, the aluminum sleeve is thinned in areas of high strains depending on the component geometry. To solve this problem an eccentric core arrangement during co-extrusion was investigated. Based on the results of FE-simulations, the experimental validation is presented in this work. Rods with an offset of 0.25, 0.5 and 0.75 mm were produced by eccentric hydrostatic co-extrusion. Ultrasonic testing was used to evaluate the bonding quality across the entire rods. For the forging investigations the basic process Rising was chosen. The still good bonding quality after forging was examined by dye penetrant testing and optical microscopy. For an optimal stress transfer between the materials across the entire component, a sufficient bonding between the materials is essential. To evaluate the interface strength, a special bending test was developed. For the conception of the bending specimens it was required to analyze the Rising specimens geometry. These analyses were performed using a reconstruction of the geometrical data based on computer tomography (CT) investigations. The comparison with the numerically deter-mined Rising specimen geometry shows good correlation. Parametric Finite Element Analyses of the bending test were used to develop the load case and the specimen geometry. By means of iterative adaption of load application, bearing and specimen geometry parameters, an advantageous stress state and experimentally applicable configuration were found. Based on this conception, the experimental setup was configured and bending tests were performed. The interface strength was deter-mined by the calculation of the maximum interlaminar interfacial tension stress using the experimental interface failure force and the bending FE model. (paper)

Experimental knee pain impairs submaximal force steadiness in isometric, eccentric, and concentric muscle actions.

Science.gov (United States)

Rice, David A; McNair, Peter J; Lewis, Gwyn N; Mannion, Jamie

2015-09-12

Populations with knee joint damage, including arthritis, have noted impairments in the regulation of submaximal muscle force. It is difficult to determine the exact cause of such impairments given the joint pathology and associated neuromuscular adaptations. Experimental pain models that have been used to isolate the effects of pain on muscle force regulation have shown impaired force steadiness during acute pain. However, few studies have examined force regulation during dynamic contractions, and these findings have been inconsistent. The goal of the current study was to examine the effect of experimental knee joint pain on submaximal quadriceps force regulation during isometric and dynamic contractions. The study involved fifteen healthy participants. Participants were seated in an isokinetic dynamometer. Knee extensor force matching tasks were completed in isometric, eccentric, and concentric muscle contraction conditions. The target force was set to 10 % of maximum for each contraction type. Hypertonic saline was then injected into the infrapatella fat pad to generate acute joint pain. The force matching tasks were repeated during pain and once more 5 min after pain had subsided. Hypertonic saline resulted in knee pain with an average peak pain rating of 5.5 ± 2.1 (0-10 scale) that lasted for 18 ± 4 mins. Force steadiness significantly reduced during pain across all three muscle contraction conditions. There was a trend to increased force matching error during pain but this was not significant. Experimental knee pain leads to impaired quadriceps force steadiness during isometric, eccentric, and concentric contractions, providing further evidence that joint pain directly affects motor performance. Given the established relationship between submaximal muscle force steadiness and function, such an effect may be detrimental to the performance of tasks in daily life. In order to restore motor performance in people with painful arthritic conditions of the

A COX-2 inhibitor reduces muscle soreness, but does not influence recovery and adaptation after eccentric exercise

DEFF Research Database (Denmark)

Paulsen, G; Egner, I M; Drange, M

2010-01-01

The aim of this study was to investigate the effect of a cyclooxygenase (COX)-2 inhibitor on the recovery of muscle function, inflammation, regeneration after, and adaptation to, unaccustomed eccentric exercise. Thirty-three young males and females participated in a double-blind, placebo-controll......The aim of this study was to investigate the effect of a cyclooxygenase (COX)-2 inhibitor on the recovery of muscle function, inflammation, regeneration after, and adaptation to, unaccustomed eccentric exercise. Thirty-three young males and females participated in a double-blind, placebo...

Elliptic Flow, Initial Eccentricity and Elliptic Flow Fluctuations in Heavy Ion Collisions at RHIC

Science.gov (United States)

Nouicer, Rachid; Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holzman, B.; Iordanova, A.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

2008-12-01

We present measurements of elliptic flow and event-by-event fluctuations established by the PHOBOS experiment. Elliptic flow scaled by participant eccentricity is found to be similar for both systems when collisions with the same number of participants or the same particle area density are compared. The agreement of elliptic flow between Au+Au and Cu+Cu collisions provides evidence that the matter is created in the initial stage of relativistic heavy ion collisions with transverse granularity similar to that of the participant nucleons. The event-by-event fluctuation results reveal that the initial collision geometry is translated into the final state azimuthal particle distribution, leading to an event-by-event proportionality between the observed elliptic flow and initial eccentricity.

Eccentric strengthening effect of hip-adductor training with elastic bands in soccer players

DEFF Research Database (Denmark)

Jensen, Jesper; Hölmich, Per; Bandholm, Thomas

2014-01-01

programme, including one hip-adduction exercise, on eccentric and isometric hip-adduction strength, using elastic bands as external load. METHODS: Thirty-four healthy, sub-elite soccer players, mean (±SD) age of 22.1 (±3.3) years, were randomised to either training or control. During the mid-season break......BACKGROUND: Soccer players with weak hip-adductor muscles are at increased risk of sustaining groin injuries. Therefore, a simple hip-adductor strengthening programme for prevention of groin injuries is needed. OBJECTIVE: We aimed to investigate the effect of an 8-week hip-adductor strengthening...... sessions per week (weeks 7-8) with 3×8 RM. Eccentric hip-adduction (EHAD), isometric hip-adduction (IHAD) and isometric hip-abduction (IHAB) strength, and the IHAD/IHAB ratio were measured assessor-blinded preintervention and postintervention, using reliable hand-held dynamometry procedures. RESULTS...

Visual spatial attention enhances the amplitude of positive and negative fMRI responses to visual stimulation in an eccentricity-dependent manner

Science.gov (United States)

Bressler, David W.; Fortenbaugh, Francesca C.; Robertson, Lynn C.; Silver, Michael A.

2013-01-01

Endogenous visual spatial attention improves perception and enhances neural responses to visual stimuli at attended locations. Although many aspects of visual processing differ significantly between central and peripheral vision, little is known regarding the neural substrates of the eccentricity dependence of spatial attention effects. We measured amplitudes of positive and negative fMRI responses to visual stimuli as a function of eccentricity in a large number of topographically-organized cortical areas. Responses to each stimulus were obtained when the stimulus was attended and when spatial attention was directed to a stimulus in the opposite visual hemifield. Attending to the stimulus increased both positive and negative response amplitudes in all cortical areas we studied: V1, V2, V3, hV4, VO1, LO1, LO2, V3A/B, IPS0, TO1, and TO2. However, the eccentricity dependence of these effects differed considerably across cortical areas. In early visual, ventral, and lateral occipital cortex, attentional enhancement of positive responses was greater for central compared to peripheral eccentricities. The opposite pattern was observed in dorsal stream areas IPS0 and putative MT homolog TO1, where attentional enhancement of positive responses was greater in the periphery. Both the magnitude and the eccentricity dependence of attentional modulation of negative fMRI responses closely mirrored that of positive responses across cortical areas. PMID:23562388

Short biceps femoris fascicles and eccentric knee flexor weakness increase the risk of hamstring injury in elite football (soccer): a prospective cohort study.

Science.gov (United States)

Timmins, Ryan G; Bourne, Matthew N; Shield, Anthony J; Williams, Morgan D; Lorenzen, Christian; Opar, David A

2016-12-01

To investigate the role of eccentric knee flexor strength, between-limb imbalance and biceps femoris long head (BFlh) fascicle length on the risk of future hamstring strain injury (HSI). Elite soccer players (n=152) from eight different teams participated. Eccentric knee flexor strength during the Nordic hamstring exercise and BFlh fascicle length were assessed at the beginning of preseason. The occurrences of HSIs following this were recorded by the team medical staff. Relative risk (RR) was determined for univariate data, and logistic regression was employed for multivariate data. Twenty seven new HSIs were reported. Eccentric knee flexor strength below 337 N (RR=4.4; 95% CI 1.1 to 17.5) and possessing BFlh fascicles shorter than 10.56 cm (RR=4.1; 95% CI 1.9 to 8.7) significantly increased the risk of a HSI. Multivariate logistic regression revealed significant effects when combinations of age, history of HSI, eccentric knee flexor strength and BFlh fascicle length were explored. From these analyses the likelihood of a future HSI in older athletes or those with a HSI history was reduced if high levels of eccentric knee flexor strength and longer BFlh fascicles were present. The presence of short BFlh fascicles and low levels of eccentric knee flexor strength in elite soccer players increases the risk of future HSI. The greater risk of a future HSI in older players or those with a previous HSI is reduced when they have longer BFlh fascicles and high levels of eccentric strength. 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/.

Effectiveness of the Intratissue Percutaneous Electrolysis (EPI®) technique and isoinertial eccentric exercise in the treatment of patellar tendinopathy at two years follow-up.

Science.gov (United States)

Abat, Ferran; Diesel, Wayne-J; Gelber, Pablo-E; Polidori, Fernando; Monllau, Joan-Carles; Sanchez-Ibañez, Jose-Manuel

2014-04-01

to show the effect of Intratissue Percutaneous Electrolysis (EPI®) combined with eccentric programme in the treatment of patellar tendinopathy. prospective study of 33 athlete-patients consecutively treated for insertional tendinopathy with Intratissue Percutaneous Electrolysis (EPI®) and followed for 2 years. Functional assessment was performed at the first visit, at three months and two years with the Tegner scale and VISA-P. an average improvement in the VISA-P of 35 points was obtained. The mean duration of treatment was 4.5 weeks. Some 78.8% of the patients returned to the same level of physical activity as before the injury by the end of treatment, reaching 100% at two years. intratissue percutaneous electrolysis (EPI®) combined with an eccentric-based rehab program offers excellent results in terms of the clinical and functional improvement of the patellar tendon with low morbidity in a short-term period. Therapy, level 4.

Reliability, Validity, and Sensitivity of a Novel Smartphone-Based Eccentric Hamstring Strength Test in Professional Football Players.

Science.gov (United States)

Lee, Justin W Y; Cai, Ming-Jing; Yung, Patrick S H; Chan, Kai-Ming

2018-05-01

To evaluate the test-retest reliability, sensitivity, and concurrent validity of a smartphone-based method for assessing eccentric hamstring strength among male professional football players. A total of 25 healthy male professional football players performed the Chinese University of Hong Kong (CUHK) Nordic break-point test, hamstring fatigue protocol, and isokinetic hamstring strength test. The CUHK Nordic break-point test is based on a Nordic hamstring exercise. The Nordic break-point angle was defined as the maximum point where the participant could no longer support the weight of his body against gravity. The criterion for the sensitivity test was the presprinting and postsprinting difference of the Nordic break-point angle with a hamstring fatigue protocol. The hamstring fatigue protocol consists of 12 repetitions of the 30-m sprint with 30-s recoveries between sprints. Hamstring peak torque of the isokinetic hamstring strength test was used as the criterion for validity. A high test-retest reliability (intraclass correlation coefficient = .94; 95% confidence interval, .82-.98) was found in the Nordic break-point angle measurements. The Nordic break-point angle significantly correlated with isokinetic hamstring peak torques at eccentric action of 30°/s (r = .88, r 2  = .77, P hamstring strength measures among male professional football players.

ORBITAL PHASE VARIATIONS OF THE ECCENTRIC GIANT PLANET HAT-P-2b

Energy Technology Data Exchange (ETDEWEB)

Lewis, Nikole K.; Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Knutson, Heather A.; Desert, Jean-Michel; Kao, Melodie [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Cowan, Nicolas B. [Center for Interdisciplinary Exploration and Research in Astrophysics and Department of Physics and Astronomy, Northwestern University, 2131 Tech Drive, Evanston, IL 60208 (United States); Laughlin, Gregory; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Burrows, Adam; Bakos, Gaspar A.; Hartman, Joel D. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Mighell, Kenneth J. [National Optical Astronomy Observatories, Tucson, AZ 85726 (United States); Agol, Eric [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Hinkley, Sasha; Johnson, John Asher [Department of Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Howard, Andrew W., E-mail: nklewis@mit.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); and others

2013-04-01

We present the first secondary eclipse and phase curve observations for the highly eccentric hot Jupiter HAT-P-2b in the 3.6, 4.5, 5.8, and 8.0 {mu}m bands of the Spitzer Space Telescope. The 3.6 and 4.5 {mu}m data sets span an entire orbital period of HAT-P-2b (P = 5.6334729 d), making them the longest continuous phase curve observations obtained to date and the first full-orbit observations of a planet with an eccentricity exceeding 0.2. We present an improved non-parametric method for removing the intrapixel sensitivity variations in Spitzer data at 3.6 and 4.5 {mu}m that robustly maps position-dependent flux variations. We find that the peak in planetary flux occurs at 4.39 {+-} 0.28, 5.84 {+-} 0.39, and 4.68 {+-} 0.37 hr after periapse passage with corresponding maxima in the planet/star flux ratio of 0.1138% {+-} 0.0089%, 0.1162% {+-} 0.0080%, and 0.1888% {+-} 0.0072% in the 3.6, 4.5, and 8.0 {mu}m bands, respectively. Our measured secondary eclipse depths of 0.0996% {+-} 0.0072%, 0.1031% {+-} 0.0061%, 0.071%{sub -0.013%}{sup +0.029,} and 0.1392% {+-} 0.0095% in the 3.6, 4.5, 5.8, and 8.0 {mu}m bands, respectively, indicate that the planet cools significantly from its peak temperature before we measure the dayside flux during secondary eclipse. We compare our measured secondary eclipse depths to the predictions from a one-dimensional radiative transfer model, which suggests the possible presence of a transient day side inversion in HAT-P-2b's atmosphere near periapse. We also derive improved estimates for the system parameters, including its mass, radius, and orbital ephemeris. Our simultaneous fit to the transit, secondary eclipse, and radial velocity data allows us to determine the eccentricity (e = 0.50910 {+-} 0.00048) and argument of periapse ({omega} = 188. Degree-Sign 09 {+-} 0. Degree-Sign 39) of HAT-P-2b's orbit with a greater precision than has been achieved for any other eccentric extrasolar planet. We also find evidence for a long

Effects of an eccentric training programme on hamstring strain injuries in women football players

Directory of Open Access Journals (Sweden)

del Ama Espinosa Gurutze

2015-09-01

Full Text Available Study aim: to test the hypothesis that an eccentric training programme applied on women football players would reduce the hamstring injury rate by improving thigh muscle balance and, particularly, hamstring strength.

Subjective Sleepiness and Sleep Quality in Adolescents are Related to Objective and Subjective Measures of School Performance.

NARCIS (Netherlands)

Boschloo, A.; Krabbendam, L.; Dekker, S.; Lee, N.; Groot, R. de; Jolles, J.

2013-01-01

This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11-18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school

THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. II. KOI-1474.01, A CANDIDATE ECCENTRIC PLANET PERTURBED BY AN UNSEEN COMPANION

Energy Technology Data Exchange (ETDEWEB)

Dawson, Rebekah I.; Murray-Clay, Ruth A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, MS-10, Cambridge, MA 02138 (United States); Johnson, John Asher; Morton, Timothy D. [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, California 95064 (United States); Howard, Andrew W., E-mail: rdawson@cfa.harvard.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States)

2012-12-20

The exoplanets known as hot Jupiters-Jupiter-sized planets with periods of less than 10 days-likely are relics of dynamical processes that shape all planetary system architectures. Socrates et al. argued that high eccentricity migration (HEM) mechanisms proposed for situating these close-in planets should produce an observable population of highly eccentric proto-hot Jupiters that have not yet tidally circularized. HEM should also create failed-hot Jupiters, with periapses just beyond the influence of fast circularization. Using the technique we previously presented for measuring eccentricities from photometry (the ''photoeccentric effect''), we are distilling a collection of eccentric proto- and failed-hot Jupiters from the Kepler Objects of Interest (KOI). Here, we present the first, KOI-1474.01, which has a long orbital period (69.7340 days) and a large eccentricity e 0.81{sup +0.10}{sub -0.07}, skirting the proto-hot Jupiter boundary. Combining Kepler photometry, ground-based spectroscopy, and stellar evolution models, we characterize host KOI-1474 as a rapidly rotating F star. Statistical arguments reveal that the transiting candidate has a low false-positive probability of 3.1%. KOI-1474.01 also exhibits transit-timing variations of the order of an hour. We explore characteristics of the third-body perturber, which is possibly the ''smoking-gun'' cause of KOI-1474.01's large eccentricity. We use the host star's period, radius, and projected rotational velocity to measure the inclination of the stellar spin. Comparing KOI 1474.01's inclination, we find that its orbit is marginally consistent with being aligned with the stellar spin axis, although a reanalysis is warranted with future additional data. Finally, we discuss how the number and existence of proto-hot Jupiters will not only demonstrate that hot Jupiters migrate via HEM, but also shed light on the typical timescale for the mechanism.

Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

NARCIS (Netherlands)

Boschloo, Annemarie; Krabbendam, Lydia; Dekker, Sanne; Lee, Nikki; De Groot, Renate; Jolles, Jelle

2016-01-01

This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11–18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school

Subjective sleepiness and sleep quality in adolescents are related to objective and subjective measures of school performance

NARCIS (Netherlands)

Boschloo, Annemarie; Krabbendam, Lydia; Dekker, Sanne; Lee, Nikki; De Groot, Renate; Jolles, Jelle

2018-01-01

This study investigated the relation between sleep and school performance in a large sam- ple of 561 adolescents aged 11–18 years. Three subjective measures of sleep were used: sleepiness, sleep quality, and sleep duration. They were compared to three measures of school performance: objective school

THE COMBINATION OF α-LIPOIC ACID INTAKE WITH ECCENTRIC EXERCISE MODULATES ERYTHROPOIETIN RELEASE.

Science.gov (United States)

Morawin, B; Turowski, D; Naczk, M; Siatkowski, I; Zembron-Lacny, A

2014-08-01

The generation of reactive nitrogen/oxygen species (RN/OS) represents an important mechanism in erythropoietin (EPO) expression and skeletal muscle adaptation to physical and metabolic stress. RN/OS generation can be modulated by intense exercise and nutrition supplements such as α-lipoic acid, which demonstrates both anti- and pro-oxidative action. The study was designed to show the changes in the haematological response through the combination of α-lipoic acid intake with running eccentric exercise. Sixteen healthy young males participated in the randomised and placebo-controlled study. The exercise trial involved a 90-min run followed by a 15-min eccentric phase at 65% VO2max (-10% gradient). It significantly increased serum concentrations of nitric oxide (NO), hydrogen peroxide (H2O2) and pro-oxidative products such as 8-isoprostanes (8-iso), lipid peroxides (LPO) and protein carbonyls (PC). α-Lipoic acid intake (Thiogamma: 1200 mg daily for 10 days prior to exercise) resulted in a 2-fold elevation of serum H2O2 concentration before exercise, but it prevented the generation of NO, 8-iso, LPO and PC at 20 min, 24 h, and 48 h after exercise. α-Lipoic acid also elevated serum EPO level, which highly correlated with NO/H2O2 ratio (r = 0.718, P exercise (placebo 732 ± 207 IU · L(-1), α-lipoic acid 481 ± 103 IU · L(-1)), and correlated with EPO (r = 0.478, P release and reduces muscle damage after running eccentric exercise.

In vitro shear stress measurements using particle image velocimetry in a family of carotid artery models: effect of stenosis severity, plaque eccentricity, and ulceration.

Directory of Open Access Journals (Sweden)

Sarah Kefayati

Full Text Available Atherosclerotic disease, and the subsequent complications of thrombosis and plaque rupture, has been associated with local shear stress. In the diseased carotid artery, local variations in shear stress are induced by various geometrical features of the stenotic plaque. Greater stenosis severity, plaque eccentricity (symmetry and plaque ulceration have been associated with increased risk of cerebrovascular events based on clinical trial studies. Using particle image velocimetry, the levels and patterns of shear stress (derived from both laminar and turbulent phases were studied for a family of eight matched-geometry models incorporating independently varied plaque features - i.e. stenosis severity up to 70%, one of two forms of plaque eccentricity, and the presence of plaque ulceration. The level of laminar (ensemble-averaged shear stress increased with increasing stenosis severity resulting in 2-16 Pa for free shear stress (FSS and approximately double (4-36 Pa for wall shear stress (WSS. Independent of stenosis severity, marked differences were found in the distribution and extent of shear stress between the concentric and eccentric plaque formations. The maximum WSS, found at the apex of the stenosis, decayed significantly steeper along the outer wall of an eccentric model compared to the concentric counterpart, with a 70% eccentric stenosis having 249% steeper decay coinciding with the large outer-wall recirculation zone. The presence of ulceration (in a 50% eccentric plaque resulted in both elevated FSS and WSS levels that were sustained longer (∼20 ms through the systolic phase compared to the non-ulcerated counterpart model, among other notable differences. Reynolds (turbulent shear stress, elevated around the point of distal jet detachment, became prominent during the systolic deceleration phase and was widely distributed over the large recirculation zone in the eccentric stenoses.

Neural network construction of flow of a viscoelastic fluid of a second order between two eccentric spheres

International Nuclear Information System (INIS)

Elbakry, M.Y.; El-Helly, M.; Elbakry, M.Y.

2010-01-01

Neural networks are widely for solving many scientific linear and non-linear problems. In this work ,we used the artificial neural network (ANN) to simulate and predict the torque and force acting on the outer stationary sphere due to steady state motion of the second order fluid between two eccentric spheres by a rotating inner sphere with an angular velocity Ω. the (ANN) model has been trained based on the experimental data to produce the torque and force at different eccentricities. The experimental and trained torque and force are compared. The designed ANN shows a good match to the experimental data.

Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy

DEFF Research Database (Denmark)

Kongsgaard, M.; Kovanen, V.; Aagaard, P.

2009-01-01

A randomized-controlled single-blind trial was conducted to investigate the clinical, structural and functional effects of peritendinous corticosteroid injections (CORT), eccentric decline squat training (ECC) and heavy slow resistance training (HSR) in patellar tendinopathy. Thirty-nine male...

Eccentric or Concentric Exercises for the Treatment of Tendinopathies?

DEFF Research Database (Denmark)

Couppé, Christian; Svensson, René B; Silbernagel, Karin Grävare

2015-01-01

with respect to parameters like load magnitude, speed of movement, and recovery period between exercise sessions. Future studies should control for these loading parameters, evaluate various exercise dosages, and also think beyond isolated eccentric exercises to arrive at firm recommendations regarding...... exercise has been promoted. In this review we cover the relevant evidence for different exercise regimes in tendinopathy rehabilitation with particular focus on the applied loads that are experienced by the tendon and how the exercise regime may affect these applied loads. There is no convincing clinical...

Effect of eccentric exercise with reduced muscle glycogen on plasma interleukin-6 and neuromuscular responses of musculus quadriceps femoris.

Science.gov (United States)

Gavin, James P; Myers, Stephen D; Willems, Mark E T

2016-07-01

Eccentric exercise can result in muscle damage and interleukin-6 (IL-6) secretion. Glycogen availability is a potent stimulator of IL-6 secretion. We examined effects of eccentric exercise in a low-glycogen state on neuromuscular function and plasma IL-6 secretion. Twelve active men (23 ± 4 yr, 179 ± 5 cm, 77 ± 10 kg, means ± SD) completed two downhill treadmill runs (gradient, -12%, 5 × 8 min; speed, 12.1 ± 1.1 km/h) with normal (NG) and reduced muscle glycogen (RG) in randomized order and at least 6 wk apart. Muscle glycogen was reduced using an established cycling protocol until exhaustion and dietary manipulation the evening before the morning run. Physiological responses were measured up to 48 h after the downhill runs. During recovery, force deficits of musculus quadriceps femoris by maximal isometric contractions were similar. Changes in low-frequency fatigue were larger with RG. Voluntary activation and plasma IL-6 levels were similar in recovery between conditions. It is concluded that unaccustomed, damaging eccentric exercise with low muscle glycogen of the m. quadriceps femoris 1) exacerbated low-frequency fatigue but 2) had no additional effect on IL-6 secretion. Neuromuscular impairment after eccentric exercise with low muscle glycogen appears to have a greater peripheral component in early recovery. Copyright © 2016 the American Physiological Society.

Heat-and-mass transfer during a laminar dissociating gas flow in eccentric annular channels

International Nuclear Information System (INIS)

Besedina, T.V.; Udot, A.V.; Yakushev, A.P.

1987-01-01

An algorithm to calculate heat-and-mass transfer processes during dissociating gas laminar flow in an eccentric annular channels is considered. Analytical solutions of the heat transfer equations for a rod clodding and gap with boundary conditions of conjugation of temperatures and heat fluxes have been used to determine temperature field. This has made it possible to proceed from slution of the conjugate problem to solution of the equation of energy only for the coolant. The results of calculation of temperature distribution along the cladding for different values of its eccentricity and thermal conductivity coefficient both for the case of frozen flow and in the presence of chemical reactions in the flow are given. When calculating temperatures with conjugation boundary conditions temperature gradients in azimuthal direction are far less and heat transfer in concentration diffusion is carried out mainly in radial direction

Subjective and objective quantification of physician's workload and performance during radiation therapy planning tasks.

Science.gov (United States)

Mazur, Lukasz M; Mosaly, Prithima R; Hoyle, Lesley M; Jones, Ellen L; Marks, Lawrence B

2013-01-01

To quantify, and compare, workload for several common physician-based treatment planning tasks using objective and subjective measures of workload. To assess the relationship between workload and performance to define workload levels where performance could be expected to decline. Nine physicians performed the same 3 tasks on each of 2 cases ("easy" vs "hard"). Workload was assessed objectively throughout the tasks (via monitoring of pupil size and blink rate), and subjectively at the end of each case (via National Aeronautics and Space Administration Task Load Index; NASA-TLX). NASA-TLX assesses the 6 dimensions (mental, physical, and temporal demands, frustration, effort, and performance); scores > or ≈ 50 are associated with reduced performance in other industries. Performance was measured using participants' stated willingness to approve the treatment plan. Differences in subjective and objective workload between cases, tasks, and experience were assessed using analysis of variance (ANOVA). The correlation between subjective and objective workload measures were assessed via the Pearson correlation test. The relationships between workload and performance measures were assessed using the t test. Eighteen case-wise and 54 task-wise assessments were obtained. Subjective NASA-TLX scores (P .1), were significantly lower for the easy vs hard case. Most correlations between the subjective and objective measures were not significant, except between average blink rate and NASA-TLX scores (r = -0.34, P = .02), for task-wise assessments. Performance appeared to decline at NASA-TLX scores of ≥55. The NASA-TLX may provide a reasonable method to quantify subjective workload for broad activities, and objective physiologic eye-based measures may be useful to monitor workload for more granular tasks within activities. The subjective and objective measures, as herein quantified, do not necessarily track each other, and more work is needed to assess their utilities. From a

Acute neuromuscular and performance responses to Nordic hamstring exercises completed before or after football training.

Science.gov (United States)

Lovell, Ric; Siegler, Jason C; Knox, Michael; Brennan, Scott; Marshall, Paul W M

2016-12-01

The optimal scheduling of Nordic Hamstring exercises (NHEs) relative to football training sessions is unknown. We examined the acute neuromuscular and performance responses to NHE undertaken either before (BT) or after (AT) simulated football training. Twelve amateur players performed six sets of five repetitions of the NHE either before or after 60 min of standardised football-specific exercise (SAFT 60 ). Surface electromyography signals (EMG) of the hamstring muscles were recorded during both the NHE, and maximum eccentric actions of the knee flexors (0.52 rad · s -1 ) performed before and after the NHE programme, and at 15 min intervals during SAFT 60 . Ten-metre sprint times were recorded on three occasions during each 15 min SAFT 60 segment. Greater eccentric hamstring fatigue following the NHE programme was observed in BT versus AT (19.8 %; very likely small effect), which was particularly apparent in the latter range of knee flexion (0-15°; 39.6%; likely moderate effect), and synonymous with hamstring EMG declines (likely small-likely moderate effects). Performing NHE BT attenuated sprint performance declines (2.0-3.2%; likely small effects), but decreased eccentric hamstring peak torque (-14.1 to -18.9%; likely small effects) during football-specific exercise. Performing NHE prior to football training reduces eccentric hamstring strength and may exacerbate hamstring injury risk.

Optimal contracts based on subjective performance evaluations and reciprocity

DEFF Research Database (Denmark)

Sebald, Alexander Christopher; Walzl, Markus

2015-01-01

As demonstrated in a recent laboratory experiment (see Sebald & Walzl, 2014), individuals tend to sanction others who subjectively evaluate their performance whenever this assessment falls short of the individuals’ self-evaluation. Interestingly, this is the case even if the individuals’ earnings...

Are subjective memory problems related to suggestibility, compliance, false memories, and objective memory performance?

Science.gov (United States)

Van Bergen, Saskia; Jelicic, Marko; Merckelbach, Harald

2009-01-01

The relationship between subjective memory beliefs and suggestibility, compliance, false memories, and objective memory performance was studied in a community sample of young and middle-aged people (N = 142). We hypothesized that people with subjective memory problems would exhibit higher suggestibility and compliance levels and would be more susceptible to false recollections than those who are optimistic about their memory. In addition, we expected a discrepancy between subjective memory judgments and objective memory performance. We found that subjective memory judgments correlated significantly with compliance, with more negative memory judgments accompanying higher levels of compliance. Contrary to our expectation, subjective memory problems did not correlate with suggestibility or false recollections. Furthermore, participants were accurate in estimating their objective memory performance.

Older Adult Multitasking Performance Using a Gaze-Contingent Useful Field of View.

Science.gov (United States)

Ward, Nathan; Gaspar, John G; Neider, Mark B; Crowell, James; Carbonari, Ronald; Kaczmarski, Hank; Ringer, Ryan V; Johnson, Aaron P; Loschky, Lester C; Kramer, Arthur F

2018-03-01

Objective We implemented a gaze-contingent useful field of view paradigm to examine older adult multitasking performance in a simulated driving environment. Background Multitasking refers to the ability to manage multiple simultaneous streams of information. Recent work suggests that multitasking declines with age, yet the mechanisms supporting these declines are still debated. One possible framework to better understand this phenomenon is the useful field of view, or the area in the visual field where information can be attended and processed. In particular, the useful field of view allows for the discrimination of two competing theories of real-time multitasking, a general interference account and a tunneling account. Methods Twenty-five older adult subjects completed a useful field of view task that involved discriminating the orientation of lines in gaze-contingent Gabor patches appearing at varying eccentricities (based on distance from the fovea) as they operated a vehicle in a driving simulator. In half of the driving scenarios, subjects also completed an auditory two-back task to manipulate cognitive workload, and during some trials, wind was introduced as a means to alter general driving difficulty. Results Consistent with prior work, indices of driving performance were sensitive to both wind and workload. Interestingly, we also observed a decline in Gabor patch discrimination accuracy under high cognitive workload regardless of eccentricity, which provides support for a general interference account of multitasking. Conclusion The results showed that our gaze-contingent useful field of view paradigm was able to successfully examine older adult multitasking performance in a simulated driving environment. Application This study represents the first attempt to successfully measure dynamic changes in the useful field of view for older adults completing a multitasking scenario involving driving.

ORBITAL PHASE VARIATIONS OF THE ECCENTRIC GIANT PLANET HAT-P-2b

International Nuclear Information System (INIS)

Lewis, Nikole K.; Showman, Adam P.; Knutson, Heather A.; Désert, Jean-Michel; Kao, Melodie; Cowan, Nicolas B.; Laughlin, Gregory; Fortney, Jonathan J.; Burrows, Adam; Bakos, Gáspár Á.; Hartman, Joel D.; Deming, Drake; Crepp, Justin R.; Mighell, Kenneth J.; Agol, Eric; Charbonneau, David; Fischer, Debra A.; Hinkley, Sasha; Johnson, John Asher; Howard, Andrew W.

2013-01-01

We present the first secondary eclipse and phase curve observations for the highly eccentric hot Jupiter HAT-P-2b in the 3.6, 4.5, 5.8, and 8.0 μm bands of the Spitzer Space Telescope. The 3.6 and 4.5 μm data sets span an entire orbital period of HAT-P-2b (P = 5.6334729 d), making them the longest continuous phase curve observations obtained to date and the first full-orbit observations of a planet with an eccentricity exceeding 0.2. We present an improved non-parametric method for removing the intrapixel sensitivity variations in Spitzer data at 3.6 and 4.5 μm that robustly maps position-dependent flux variations. We find that the peak in planetary flux occurs at 4.39 ± 0.28, 5.84 ± 0.39, and 4.68 ± 0.37 hr after periapse passage with corresponding maxima in the planet/star flux ratio of 0.1138% ± 0.0089%, 0.1162% ± 0.0080%, and 0.1888% ± 0.0072% in the 3.6, 4.5, and 8.0 μm bands, respectively. Our measured secondary eclipse depths of 0.0996% ± 0.0072%, 0.1031% ± 0.0061%, 0.071% -0.013% +0.029, and 0.1392% ± 0.0095% in the 3.6, 4.5, 5.8, and 8.0 μm bands, respectively, indicate that the planet cools significantly from its peak temperature before we measure the dayside flux during secondary eclipse. We compare our measured secondary eclipse depths to the predictions from a one-dimensional radiative transfer model, which suggests the possible presence of a transient day side inversion in HAT-P-2b's atmosphere near periapse. We also derive improved estimates for the system parameters, including its mass, radius, and orbital ephemeris. Our simultaneous fit to the transit, secondary eclipse, and radial velocity data allows us to determine the eccentricity (e = 0.50910 ± 0.00048) and argument of periapse (ω = 188.°09 ± 0.°39) of HAT-P-2b's orbit with a greater precision than has been achieved for any other eccentric extrasolar planet. We also find evidence for a long-term linear trend in the radial velocity data. This trend suggests the presence of

Friction and Wear Reduction of Eccentric Journal Bearing Made of Sn-Based Babbitt for Ore Cone Crusher.

Science.gov (United States)

Amanov, Auezhan; Ahn, Byungmin; Lee, Moon Gu; Jeon, Yongho; Pyun, Young-Sik

2016-11-22

An anti-friction Babbitt alloy-coated bearing made by a casting process is a journal bearing, which is used in an ore cone crusher eccentric. The main purpose of the Babbitt coated eccentric is to provide a low friction to support and guide a rotating shaft. Despite the fact that the Babbitt-coated eccentric offers a low friction coefficient and can be operated without a continuous supply of lubricant, it suffers from mining environments and short service life. In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique was used to further reduce the friction coefficient, to increase the wear resistance, and to extend the service life of the Sn-based Babbitt metal. The friction and wear behavior of the Sn-based Babbitt metal was investigated using a block-on-ring tester under both dry and oil-lubricated conditions. The results of the experiments revealed that the friction and wear behavior of Sn-based Babbitt metal could be improved by the application of the UNSM technique. The friction and wear mechanisms of the specimens were explained and discussed in terms of changes in surface properties-microstructure, surface hardness, surface roughness, etc.

Friction and Wear Reduction of Eccentric Journal Bearing Made of Sn-Based Babbitt for Ore Cone Crusher

Directory of Open Access Journals (Sweden)

Auezhan Amanov

2016-11-01

Full Text Available An anti-friction Babbitt alloy-coated bearing made by a casting process is a journal bearing, which is used in an ore cone crusher eccentric. The main purpose of the Babbitt coated eccentric is to provide a low friction to support and guide a rotating shaft. Despite the fact that the Babbitt-coated eccentric offers a low friction coefficient and can be operated without a continuous supply of lubricant, it suffers from mining environments and short service life. In this study, an ultrasonic nanocrystalline surface modification (UNSM technique was used to further reduce the friction coefficient, to increase the wear resistance, and to extend the service life of the Sn-based Babbitt metal. The friction and wear behavior of the Sn-based Babbitt metal was investigated using a block-on-ring tester under both dry and oil-lubricated conditions. The results of the experiments revealed that the friction and wear behavior of Sn-based Babbitt metal could be improved by the application of the UNSM technique. The friction and wear mechanisms of the specimens were explained and discussed in terms of changes in surface properties—microstructure, surface hardness, surface roughness, etc.

The effects of low and moderate doses of caffeine supplementation on upper and lower body maximal voluntary concentric and eccentric muscle force.

Science.gov (United States)

Tallis, Jason; Yavuz, Harley C M

2018-03-01

Despite the growing quantity of literature exploring the effect of caffeine on muscular strength, there is a dearth of data that directly explores differences in erogenicity between upper and lower body musculature and the dose-response effect. The present study sought to investigate the effects of low and moderate doses of caffeine on the maximal voluntary strength of the elbow flexors and knee extensors. Ten nonspecifically strength-trained, recreationally active participants (aged 21 ± 0.3 years) completed the study. Using a randomised, counterbalanced, and double-blind approach, isokinetic concentric and eccentric strength was measured at 60 and 180°/s following administration of a placebo, 3 mg·kg -1 body mass caffeine, and 6 mg·kg -1 body mass caffeine. There was no effect of caffeine on the maximal voluntary concentric and eccentric strength of the elbow flexors, or the eccentric strength of the knee extensors. Both 3 and 6 mg·kg -1 body mass caffeine caused a significant increase in peak concentric force of the knee extensors at 180°/s. No difference was apparent between the 2 concentrations. Only 6 mg·kg -1 body mass caused an increase in peak concentric force during repeated contractions. The results infer that the effective caffeine concentration to evoke improved muscle performance may be related to muscle mass and contraction type. The present work indicates that a relatively low dose of caffeine treatment may be effective for improving lower body muscular strength, but may have little benefit for the strength of major muscular groups of the upper body.

Separate first- and second-order processing is supported by spatial summation estimates at the fovea and eccentrically.

Science.gov (United States)

Sukumar, Subash; Waugh, Sarah J

2007-03-01

We estimated spatial summation areas for the detection of luminance-modulated (LM) and contrast-modulated (CM) blobs at the fovea, 2.5, 5 and 10 deg eccentrically. Gaussian profiles were added or multiplied to binary white noise to create LM and CM blob stimuli and these were used to psychophysically estimate detection thresholds and spatial summation areas. The results reveal significantly larger summation areas for detecting CM than LM blobs across eccentricity. These differences are comparable to receptive field size estimates made in V1 and V2. They support the notion that separate spatial processing occurs for the detection of LM and CM stimuli.

Wandering saints : Chan eccentrics in the art and culture of Song and Yuan China

NARCIS (Netherlands)

Paul, Paramita

2009-01-01

In Chinese history, few personalities compare to the Chan eccentrics. These legendary, exceptional monks, including the friends Hanshan and Shide, their teacher Fenggan, and Budai, supposedly dwelled in the mountains and cities of southeast China between the seventh and tenth centuries. Dressed in

Rehabilitation After Hamstring-Strain Injury Emphasizing Eccentric Strengthening at Long Muscle Lengths: Results of Long-Term Follow-Up.

Science.gov (United States)

Tyler, Timothy F; Schmitt, Brandon M; Nicholas, Stephen J; McHugh, Malachy P

2017-04-01

Hamstring-strain injuries have a high recurrence rate. To determine if a protocol emphasizing eccentric strength training with the hamstrings in a lengthened position resulted in a low recurrence rate. Longitudinal cohort study. Sports-medicine physical therapy clinic. Fifty athletes with hamstring-strain injury (age 36 ± 16 y; 30 men, 20 women; 3 G1, 43 G2, 4 G3; 25 recurrent injuries) followed a 3-phase rehabilitation protocol emphasizing eccentric strengthening with the hamstrings in a lengthened position. Injury recurrence; isometric hamstring strength at 80°, 60°, 40°, and 20° knee flexion in sitting with the thigh flexed to 40° above the horizontal and the seat back at 90° to the horizontal (strength tested before return to sport). Four of the 50 athletes sustained reinjuries between 3 and 12 mo after return to sport (8% recurrence rate). The other 42 athletes had not sustained a reinjury at an average of 24 ± 12 mo after return to sport. Eight noncompliant athletes did not complete the rehabilitation and returned to sport before initiating eccentric strengthening in the lengthened state. All 4 reinjuries occurred in these noncompliant athletes. At time of return to sport, compliant athletes had full restoration of strength while noncompliant athletes had significant hamstring weakness, which was progressively worse at longer muscle lengths (compliance × side × angle P = .006; involved vs noninvolved at 20°, compliant 7% stronger, noncompliant 43% weaker). Compliance with rehabilitation emphasizing eccentric strengthening with the hamstrings in a lengthened position resulted in no reinjuries.

Influence of Arm-cranking on Changes in Plasma CK Activity after High Force Eccentric Exercise of the Elbow Flexors

OpenAIRE

Kosaka, Kazunori; Sakamoto, Kei; Newton, Mike

2002-01-01

NOSAKA, K., SAKAMOTO, K. and NEWTON, M., Influence of Armcranking on Changes in Plasma CK Activlty after High Force Eccentric Exerclse of the Elbow Flexours. Abv. Exerc. Sports Physiol., Vol.8, No.2 pp.45-50, 2002. It was hypothesized that the time course of changes in plasma creatine kinase(CK) activity following eccentrie exercise was influenced by rhythmical muscle contractions performned after eccentric exercise. This study examined whether arm-cranking (AC) alters the time course of chan...

Eccentric knee flexor strength profiles of 341 elite male academy and senior Gaelic football players: Do body mass and previous hamstring injury impact performance?

Science.gov (United States)

Roe, Mark; Malone, Shane; Delahunt, Eamonn; Collins, Kieran; Gissane, Conor; Persson, Ulrik McCarthy; Murphy, John C; Blake, Catherine

2018-05-01

Report eccentric knee flexor strength values of elite Gaelic football players from underage to adult level whilst examining the influence of body mass and previous hamstring injury. Cross-sectional study. Team's training facility. Elite Gaelic football players (n = 341) from under 14 years to senior age-grades were recruited from twelve teams. Absolute (N) and relative (N·kg -1 ) eccentric hamstring strength as well as corresponding between-limb imbalances (%) were calculated for all players. Mean maximum force was 329.4N (95% CI 319.5-340.2) per limb. No statistically significant differences were observed in relative force values (4.4 N ·kg -1 , 95% CI 4.2-4.5) between age-groups. Body mass had moderate-to-large and weak associations with maximum force in youth (r = 0.597) and adult (r =0 .159) players, respectively. Overall 40% (95 CI 31.4-48.7) presented with a maximum strength between-limb imbalance >10%. Players with a hamstring injury had greater relative maximum force (9.3%, 95% CI 7.0-11.8; p > 0.05) and a 28% (95% CI 10.0-38.0) higher prevalence of between-limb imbalances ≥15% compared to their uninjured counterparts. Overlapping strength profiles across age-groups, combined with greater strength in previously injured players, suggests difficulties for establishing cut-off thresholds associated with hamstring injury risk. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Novel Mach-Zehnder Interferometer Using Eccentric-Core Fiber Design for Optical Coherence Tomography.

Science.gov (United States)

Xiong, Qiao; Tong, Xinglin; Deng, Chengwei; Zhang, Cui; Wang, Pengfei; Zheng, Zhiyuan; Liu, Fang

2018-05-13

A novel Mach-Zehnder interferometer using eccentric-core fiber (ECF) design for optical coherence tomography (OCT) is proposed and demonstrated. Instead of the commercial single-mode fiber (SMF), the ECF is used as one interference arm of the implementation. Because of the offset location of the eccentric core, it is sensitive to directional bending and the optical path difference (OPD) of two interference arms can be adjusted with high precision. The birefringence of ECF is calculated and experimentally measured, which demonstrates the polarization sensitivity of the ECF proposed in the paper is similar to that of SMF. Such a structure can replace the reference optical delay line to form an all-fiber passive device. A mirror is used as a sample for analyzing the ECF bending responses of the system. Besides, four pieces of overlapping glass slides as sample are experimentally measured as well.

Performing Materiality: Rethinking the Subject-Object Relationship as a Site of Exchange in Performance Practice

OpenAIRE

Hussein, Nesreen

2011-01-01

This thesis reconsiders the relationship between the human subject and the physical object in performance practice, which has been commonly perceived within hierarchical systems of instrumentalisation. The thesis demonstrates that in processes of performance making and reception, the role of physical objects goes beyond mimesis and direct representation. Physical objects and materials have the capacity to take active parts in a complex and multilayered performance dynamic, articulating ways o...

Improved automated perimetry performance in elderly subjects after listening to Mozart.

Science.gov (United States)

Marques, Junia Cabral; Vanessa, Adriana Chaves Oliveira; Fiorelli, Macedo Batista; Kasahara, Niro

2009-01-01

To evaluate the performance of automated perimetry of elderly subjects naïve to AP after listening to a Mozart sonata. Automated perimetry (AP) is a psychophysical test used to assess visual fields in patients with neurological disorders and glaucoma. In a previous study, Fiorelli et al. showed that young subjects who listened to a Mozart sonata prior to undergoing AP performed better in terms of reliability than those who did not listen to the sonata. Fifty-two AP-naïve, normal subjects underwent Automated perimetry (SITA 24-2). The study group (25 subjects) underwent AP after listening to Mozart's Sonata for Two Pianos in D Major, and the control group (27 subjects) underwent Automated perimetry without prior exposure to the music. The study group had significantly lower false negative rates and a lower visual field reliability score than the controls (P=0.04 and P=0.04, respectively). The test time was shorter for the study group (P=0.03). This study shows that elderly subjects, when exposed to the Mozart sonata immediately before AP testing, have lower false negative rates and lower visual field reliability scores when compared with an age- and gender-matched control group. Our results differ from those of Fiorelli et al. who found lower false positive rates and less fixation loss in addition to lower false negative rates. Listening to a Mozart sonata seems to improve automated perimetry reliability in elderly subjects.

Predicting subjective vitality and performance in sports: the role of passion and achievement goals.

Science.gov (United States)

Li, Chiung-Huang

2010-06-01

The major purpose of this study was to test the hypothesized paths from dualistic passions through achievement goals to subjective vitality and performance in sports. 645 high school athletes participated. The proposed structural equation model, with relationships between dualistic passions and subjective vitality and sports performance mediated by achievement goals, fit the data well, especially for mastery-approach and performance-approach goals. Harmonious and obsessive passions may lead athletes to high performance via the adoption of mastery-approach goals. However, these passions seem to have two paths influencing personal functioning: direct effects make players feel energetic, and indirect effects on subjective vitality through adoption of mastery-approach and performance-approach goals.

Static, dynamic balance and functional performance in subjects with and without plantar fasciitis

Directory of Open Access Journals (Sweden)

Geiseane Aguiar Gonçalves

Full Text Available Abstract Introduction: Plantar fasciitis (PF is characterized by non-inflammatory degeneration and pain under the heel, and is one of the most common foot complaints. The compensations and adjustments made to decrease the discomfort caused by the disease are clinical findings and can be a factor that contributes to impaired balance and decreased functional performance. Objective: To compare functional performance as well as static and dynamic balance among subjects with and without PF. Methods: The sample consisted of 124 subjects of both sexes aged 20-60 years. Participants were divided into two groups: a bilateral PF group (PFG; n = 62 and a control group (CG, n = 62. The following outcomes were analyzed: static and dynamic balance (using functional tests and functional performance (using a questionnaire. We used Student’s t test for independent samples to compare variables between the groups. The alpha error was set at 0.05. Results: Subjects with PF showed greater impairment in their overall dynamic balance performance (p < 0.001 than the control group, except for left posteromedial movement (p = 0.19. The CG showed showed better functional performance (p < 0.001 than the PF group. There was no difference between groups for the variable static balance on stable (p = 0.160 and unstable surfaces (p = 0.085. Conclusion: Subjects with PF displayed smaller reach distances in the overall Star Excursion Balance Test (SEBT, demonstrating a deficit in dynamic balance and functional performance when compared with healthy subjects.

Manual therapy and eccentric exercise in the management of Achilles tendinopathy.

Science.gov (United States)

Jayaseelan, Dhinu J; Kecman, Michael; Alcorn, Daniel; Sault, Josiah D

2017-05-01

Chronic Achilles tendinopathy (AT) is an overuse condition seen among runners. Eccentric exercise can decrease pain and improve function for those with chronic degenerative tendon changes; however, some individuals have continued pain requiring additional intervention. While joint mobilization and manipulation has not been studied in the management in Achilles tendinopathy, other chronic tendon dysfunction, such as lateral epicondylalgia, has responded well to manual therapy (MT). Three runners were seen in physical therapy (PT) for chronic AT. They were prescribed eccentric loading exercises and calf stretching. Joint mobilization and manipulation was implemented to improve foot and ankle mobility, decrease pain, and improve function. Immediate within-session changes in pain, heel raise repetitions, and pressure pain thresholds (PPT) were noted following joint-directed MT in each patient. Each patient improved in self-reported function on the Achilles tendon specific Victorian Institute for Sport Assessment questionnaire (VISA-A), pain levels, PPT, joint mobility, ankle motion, and single-leg heel raises at discharge and 9-month follow-up. The addition of MT directed at local and remote sites may enhance the rehabilitation of patients with AT. Further research is necessary to determine the efficacy of adding joint mobilization to standard care for AT. Case series. Therapy, Level 4.

[Benefits of Decumanum Phlebodium intake on the muscle damage in the response to intense physical exercise in sedentary subjects].

Science.gov (United States)

Vargas Corzo, M C; Aguilar Cordero, M J; de Teresa Galván, C; Segura Millán, D; Miranda Leon, M T; Castillo Rueda, G; Guisado Barrilao, R

2014-06-01

Intense physical exercise provoke muscle damage, that in sedentary people can increase cardiovascular risk. Phlebodium decumanum (PD) has shown to have immunomodulator effects in models of moderate intense physical activities in well conditioned groups. To evaluate the PD effects during eccentric exercise, as a model of muscle inflammation protocol, on a sedentary population with cardiovascular risk. This is an experimental, double-blind, multigroup randomized study. Experimental Group 1 (n = 17)received PD, 9 doses of 400 mg (total amount 3.6 g) every 8 hours during 3 days, and Control Group 2 (n = 16)received a placebo. All the subjects performed two treadmill ergoespirometry tests: first, a modified Bruce protocol to discard ischemic responses during exercise and to evaluate VO2max before the experimental phase;and second, with an eccentric protocol (14% descending ramp test) during 10 minutes in stable state at 70-80%VO2max, as experimental inflammatory protocol.We compared intra and inter groups to evaluate differences in the pre and post-test differences results on blood muscle damage variables. The study shown statistically significant differences in all pre-post intra-groups results in muscle damage variables (CK, LDH and Myoglobin, but not in Cardiac Troponin), and in functional lower-limb test (SJand CMJ). The comparison of inter-group results shown less muscle damage and less functional lower-limb deterioration in Group 1 compared with Control group, with statistical significance in both cases. Differences in handgrip dynamometry were no statistically significant. The eccentric exercise protocol in that study has proven to be a good model to induce muscle and functional damage in sedentary people. Short PD treatment has shown to reduce muscle and functional acute damages compared with placebo control group in this specific population. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

arXiv Does shape matter? v_2 vs eccentricity in small x gluon production

CERN Document Server

Kovner, Alex

We study analytically and numerically effects of spatial eccentricity of the projectile shape on the second flow harmonic in inclusive gluon production in p-A collisions in the CGC framework. Keeping the collision area fixed, we find that the two quantities are anti-correlated.

Role of calpain in eccentric contraction-induced proteolysis of Ca2+-regulatory proteins and force depression in rat fast-twitch skeletal muscle.

Science.gov (United States)

Kanzaki, Keita; Watanabe, Daiki; Kuratani, Mai; Yamada, Takashi; Matsunaga, Satoshi; Wada, Masanobu

2017-02-01

The aim of this study was to examine the in vivo effects of eccentric contraction (ECC) on calpain-dependent proteolysis of Ca 2+ -regulatory proteins and force production in fast-twitch skeletal muscles. Rat extensor digitorum longus muscles were exposed to 200 repeated ECC in situ and excised immediately [recovery 0 (REC0)] or 3 days [recovery 3 (REC3)] after cessation of ECC. Calpain inhibitor (CI)-treated rats were intraperitoneally injected with MDL-28170 before ECC and during REC3. Tetanic force was markedly reduced at REC0 and remained reduced at REC3. CI treatment ameliorated the ECC-induced force decline but only at REC3. No evidence was found for proteolysis of dihydropyridine receptor (DHPR), junctophilin (JP)1, JP2, ryanodine receptor (RyR), sarcoplasmic reticulum Ca 2+ -ATPase (SERCA)1a, or junctional face protein-45 at REC0. At REC3, ECC resulted in decreases in DHPR, JP1, JP2, RyR, and SERCA1a. CI treatment prevented the decreases in DHPR, JP1, and JP2, whereas it had little effect on RyR and SERCA1a. These findings suggest that DHPR, JP1, and JP2, but not RyR and SERCA1a, undergo calpain-dependent proteolysis in in vivo muscles subjected to ECC and that impaired function of DHPR and/or JP might cause prolonged force deficits with ECC. NEW & NOTEWORTHY Calpain-dependent proteolysis is one of the contributing factors to muscle damage that occurs with eccentric contraction (ECC). It is unclear, however, whether calpains account for proteolysis of Ca 2+ -regulatory proteins in in vivo muscles subjected to ECC. Here, we provide evidence that dihydropyridine receptor and junctophilin, but not ryanodine receptor and sarcoplasmic reticulum Ca 2+ -ATPase, undergo calpain-dependent proteolysis. Copyright © 2017 the American Physiological Society.

THE COMBINATION OF α-LIPOIC ACID INTAKE WITH ECCENTRIC EXERCISE MODULATES ERYTHROPOIETIN RELEASE

Directory of Open Access Journals (Sweden)

B. Morawin

2014-08-01

Full Text Available The generation of reactive nitrogen/oxygen species (RN/OS represents an important mechanism in erythropoietin (EPO expression and skeletal muscle adaptation to physical and metabolic stress. RN/OS generation can be modulated by intense exercise and nutrition supplements such as α-lipoic acid, which demonstrates both anti- and pro-oxidative action. The study was designed to show the changes in the haematological response through the combination of α-lipoic acid intake with running eccentric exercise. Sixteen healthy young males participated in the randomised and placebo-controlled study. The exercise trial involved a 90-min run followed by a 15-min eccentric phase at 65% VO2max (-10% gradient. It significantly increased serum concentrations of nitric oxide (NO, hydrogen peroxide (H2O2 and pro-oxidative products such as 8-isoprostanes (8-iso, lipid peroxides (LPO and protein carbonyls (PC. α-Lipoic acid intake (Thiogamma: 1200 mg daily for 10 days prior to exercise resulted in a 2-fold elevation of serum H2O2 concentration before exercise, but it prevented the generation of NO, 8-iso, LPO and PC at 20 min, 24 h, and 48 h after exercise. α-Lipoic acid also elevated serum EPO level, which highly correlated with NO/H2O2 ratio (r=0.718, P<0.01. Serum total creatine kinase (CK activity, as a marker of muscle damage, reached a peak at 24 h after exercise (placebo 732 ± 207 IU · L-1, α-lipoic acid 481 ± 103 IU · L-1, and correlated with EPO (r = 0.478, P<0.01 in the α-lipoic acid group. In conclusion, the intake of high α-lipoic acid modulates RN/OS generation, enhances EPO release and reduces muscle damage after running eccentric exercise.

Improved automated perimetry performance in elderly subjects after listening to Mozart

Directory of Open Access Journals (Sweden)

Junia Cabral Marques

2009-01-01

Full Text Available PURPOSE: To evaluate the performance of automated perimetry of elderly subjects naïve to AP after listening to a Mozart sonata. INTRODUCTION: Automated perimetry (AP is a psychophysical test used to assess visual fields in patients with neurological disorders and glaucoma. In a previous study, Fiorelli et al. showed that young subjects who listened to a Mozart sonata prior to undergoing AP performed better in terms of reliability than those who did not listen to the sonata. METHODS: Fifty-two AP-naïve, normal subjects underwent Automated perimetry (SITA 24-2. The study group (25 subjects underwent AP after listening to Mozart's Sonata for Two Pianos in D Major, and the control group (27 subjects underwent Automated perimetry without prior exposure to the music. RESULTS: The study group had significantly lower false negative rates and a lower visual field reliability score than the controls (P=0.04 and P=0.04, respectively. The test time was shorter for the study group (P=0.03. DISCUSSION: This study shows that elderly subjects, when exposed to the Mozart sonata immediately before AP testing, have lower false negative rates and lower visual field reliability scores when compared with an age- and gender-matched control group. Our results differ from those of Fiorelli et al. who found lower false positive rates and less fixation loss in addition to lower false negative rates. CONCLUSION: Listening to a Mozart sonata seems to improve automated perimetry reliability in elderly subjects.

Use of pressurized eccentric tubes to study the effect of hydrostatic stress on swelling

International Nuclear Information System (INIS)

Wolfer, W.G.; Reiley, T.C.

1977-05-01

A technique for measuring the effect of hydrostatic stress on radiation-induced swelling is presented. This technique is based on the nonuniform hydrostatic stress that arises when an eccentric tube (a tube with inner and outer surfaces having dissimilar centers of revolution) is internally pressurized. The elastic analyses of the thin- and thick-walled eccentric tube are given. The elastic stress state is allowed to relax plastically, based on a constitutive law for deformation during neutron irradiation. In this case, the constitutive law contains a linearly stress-dependent deviatoric strain rate and a dilatation rate that is linearly dependent on hydrostatic stress. Emphasis is placed on the specimen design and experimental procedure for in-reactor experiments in which the coefficient relating hydrostatic stress and swelling is sought. It is shown that, for the 316L stainless steel specimens placed in EBR-II, we may expect that any appreciable effect of hydrostatic stress on swelling will be observable through changes in specimen curvature

Detection of Static Eccentricity Fault in Saturated Induction Motors by Air-Gap Magnetic Flux Signature Analysis Using Finite Element Method

Directory of Open Access Journals (Sweden)

N. Halem

2013-06-01

Full Text Available Unfortunately, motor current signature analysis (MCSA cannot detect the small degrees of the purely static eccentricity (SE defects, while the air-gap magnetic flux signature analysis (FSA is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE method. In order to show the impact of magnetic saturation upon the diagnosis of SE fault, the analysis is carried out for saturated induction motors. The index signatures of static eccentricity fault around fundamental and PSHs are detected successfully for saturated motor.

DETECTION OF STATIC ECCENTRICITY FAULT IN SATURATED INDUCTION MOTORS BY AIR-GAP MAGNETIC FLUX SIGNATURE ANALYSIS USING FINITE ELEMENT METHOD

Directory of Open Access Journals (Sweden)

N. Halem

2013-06-01

Full Text Available Unfortunately, motor current signature analysis (MCSA cannot detect the small degrees of the purely static eccentricity (SE defects, while the air-gap magnetic flux signature analysis (FSA is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE method. In order to show the impact of magnetic saturation upon the diagnosis of SE fault, the analysis is carried out for saturated induction motors. The index signatures of static eccentricity fault around fundamental and PSHs are detected successfully for saturated motor.

DETECTION OF STATIC ECCENTRICITY FAULT IN SATURATED INDUCTION MOTORS BY AIR-GAP MAGNETIC FLUX SIGNATURE ANALYSIS USING FINITE ELEMENT METHOD

Directory of Open Access Journals (Sweden)

N. Halem

2015-07-01

Full Text Available Unfortunately, motor current signature analysis (MCSA cannot detect the small degrees of the purely static eccentricity (SE defects, while the air-gap magnetic flux signature analysis (FSA is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE method. In order to show the impact of magnetic saturation upon the diagnosis of SE fault, the analysis is carried out for saturated induction motors. The index signatures of static eccentricity fault around fundamental and PSHs are detected successfully for saturated motor.

Subjective Performance Evaluations, Self-esteem, and Ego-threats in Principal-agent Relations

DEFF Research Database (Denmark)

Sebald, Alexander Christopher; Walzl, Markus

find that agents sanction whenever the feedback of principals is below their subjective self-evaluations even if the agents' payoff is independent of the principals' feedback. Based on our experimental analysis we propose a principal-agent model with subjective performance evaluations that accommodates...

Elliptical excisions: variations and the eccentric parallelogram.

Science.gov (United States)

Goldberg, Leonard H; Alam, Murad

2004-02-01

The elliptical (fusiform) excision is a basic tool of cutaneous surgery. To assess the design, functionality, ease of construction, and aesthetic outcomes of the ellipse. A systematic review of elliptical designs and their site-specific benefits and limitations. In particular, we consider the (1). context of prevailing relaxed skin tension lines and tissue laxity; and (2). removal of the smallest possible amount of tissue around the lesion and in the "dog-ears." Attention is focused on intuitive methods that can be reproducibly planned and executed. Elliptical variations are easily designed and can be adapted to many situations. The eccentric parallelogram excision is offered as a new technique that minimizes notching and focal tension in the center of an elliptical closure. Conclusion The elliptical (fusiform) excision is an efficient, elegant, and versatile technique that will remain a mainstay of the cutaneous surgical armamentarium.

COMPARISON OF CONCENTRIC AND ECCENTRIC HAMSTRING STRENGTH TRAINING IN IMPROVING MUSCLE STRENGTH AND POWER AMONG FUTSAL PLAYERS A RANDOMIZED CONTROLLED TRIAL

Directory of Open Access Journals (Sweden)

Arunkumar Nedunchezhiyan

2016-12-01

Full Text Available Background: Hamstring injury is a common problem in many sports, especially those involving acceleration and maximal sprints. Hamstring strains are both common and painful. During sprinting the hip flexor and knee extensor torques are frequently produced and is opposed by the hamstring muscles, hence there are numerous studies done on the muscle strength training to prevent the hamstring strain injury as it is statistically stated as the highest rate involved injury in the contact sport. This study has been focused to evaluate the effectiveness of concentric and eccentric exercises in improving hamstring muscle strength and power among futsal players. Method: Thirty recreational futsal players were recruited for the study and were randomly divided into two groups. Each group received either hamstring curl exercise (concentric or Nordic hamstring exercise (eccentric twice a week for 4 weeks. The manual muscle test (MMT and 40-yard dash test was used to evaluate the muscle strength and power respectively by comparing the pretest and posttest values for both groups. Results: Wilcoxon signed rank test showed that there is no statistically significant difference between pre and post test values of MMT (Concentric (right side, z=.317; left side, z=.157, Eccentric (right side, z=.157; left side, z=.317 in both groups. Based on paired 't' test there is a significant difference between the pre and post test on improving muscle power [Concentric group, P=.020; Eccentric Group, P=.000]. Mann–Whitney U test and unpaired 't' test showed that there is no significant difference between both groups of MMT (z=.775 and 40-yard dash test (P=.707 respectively. Conclusion: The concentric strength training and eccentric strength training have a similar effect in improving hamstring muscle power in futsal players.

Beyond the geodesic approximation: Conservative effects of the gravitational self-force in eccentric orbits around a Schwarzschild black hole

International Nuclear Information System (INIS)

Barack, Leor; Sago, Norichika

2011-01-01

We study conservative finite-mass corrections to the motion of a particle in a bound (eccentric) strong-field orbit around a Schwarzschild black hole. We assume the particle's mass μ is much smaller than the black hole mass M, and explore post-geodesic corrections of O(μ/M). Our analysis uses numerical data from a recently developed code that outputs the Lorenz-gauge gravitational self-force (GSF) acting on the particle along the eccentric geodesic. First, we calculate the O(μ/M) conservative correction to the periastron advance of the orbit, as a function of the (gauge-dependent) semilatus rectum and eccentricity. A gauge-invariant description of the GSF precession effect is made possible in the circular-orbit limit, where we express the correction to the periastron advance as a function of the invariant azimuthal frequency. We compare this relation with results from fully nonlinear numerical-relativistic simulations. In order to obtain a gauge-invariant measure of the GSF effect for fully eccentric orbits, we introduce a suitable generalization of Detweiler's circular-orbit ''redshift'' invariant. We compute the O(μ/M) conservative correction to this invariant, expressed as a function of the two invariant frequencies that parametrize the orbit. Our results are in good agreement with results from post-Newtonian calculations in the weak-field regime, as we shall report elsewhere. The results of our study can inform the development of analytical models for the dynamics of strongly gravitating binaries. They also provide an accurate benchmark for future numerical-relativistic simulations.

Evaluating Robotic Surgical Skills Performance Under Distractive Environment Using Objective and Subjective Measures.

Science.gov (United States)

Suh, Irene H; LaGrange, Chad A; Oleynikov, Dmitry; Siu, Ka-Chun

2016-02-01

Distractions are recognized as a significant factor affecting performance in safety critical domains. Although operating rooms are generally full of distractions, the effect of distractions on robot-assisted surgical (RAS) performance is unclear. Our aim was to investigate the effect of distractions on RAS performance using both objective and subjective measures. Fifteen participants performed a knot-tying task using the da Vinci Surgical System and were exposed to 3 distractions: (1) passive distraction entailed listening to noise with a constant heart rate, (2) active distraction included listening to noise and acknowledging a change of random heart rate from 60 to 120 bpm, and (3) interactive distraction consisted of answering math questions. The objective kinematics of the surgical instrument tips were used to evaluate performance. Electromyography (EMG) of the forearm and hand muscles of the participants were collected. The median EMG frequency (EMG(fmed)) and the EMG envelope (EMG(env)) were analyzed. NASA Task Load Index and Fundamentals of Laparoscopic Surgery score were used to evaluate the subjective performance. One-way repeated analysis of variance was applied to examine the effects of distraction on skills performance. Spearman's correlations were conducted to compare objective and subjective measures. Significant distraction effect was found for all objective kinematics measures (P < .05). There were significant distraction effects for EMG measures (EMG(env), P < .004; EMG(fmed), P = .031). Significant distraction effects were also found for subjective measurements. Distraction impairs surgical skills performance and increases muscle work. Understanding how the surgeons cope with distractions is important in developing surgical education. © The Author(s) 2015.

Possible Outcomes of Coplanar High-eccentricity Migration: Hot Jupiters, Close-in Super-Earths, and Counter-orbiting Planets

Energy Technology Data Exchange (ETDEWEB)

Xue, Yuxin; Masuda, Kento; Suto, Yasushi, E-mail: yuxin@utap.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan)

2017-02-01

We investigate the formation of close-in planets in near-coplanar eccentric hierarchical triple systems via the secular interaction between an inner planet and an outer perturber (Coplanar High-eccentricity Migration; CHEM). We generalize the previous work on the analytical condition for successful CHEM for point masses interacting only through gravity by taking into account the finite mass effect of the inner planet. We find that efficient CHEM requires that the systems should have m {sub 1}≪m {sub 0} and m {sub 1} ≪ m {sub 2}. In addition to the gravity for point masses, we examine the importance of the short-range forces, and provide an analytical estimate of the migration timescale. We perform a series of numerical simulations in CHEM for systems consisting of a Sun-like central star, giant gas inner planet, and planetary outer perturber, including the short-range forces and stellar and planetary dissipative tides. We find that most of such systems end up with a tidal disruption; a small fraction of the systems produce prograde hot Jupiters (HJs), but no retrograde HJ. In addition, we extend CHEM to super-Earth mass range, and show that the formation of close-in super-Earths in prograde orbits is also possible. Finally, we carry out CHEM simulation for the observed hierarchical triple and counter-orbiting HJ systems. We find that CHEM can explain a part of the former systems, but it is generally very difficult to reproduce counter-orbiting HJ systems.

Influence of layer eccentricity on the resonant properties of cylindrical active coated nano-particles

DEFF Research Database (Denmark)

Thorsen, R. O.; Arslanagic, Samel

2015-01-01

We report on the influence of the layer eccentricity on the resonant properties of active coated nano-particles made of a silver core and gain impregnated silica shell illuminated by a near-by magnetic line source. For a fixed over-all size of the particle, designs with small and large cores...

Changes in water content in response to an acute bout of eccentric loading in a patellar tendon with a history of tendinopathy: A case report.

Science.gov (United States)

Ho, Kai-Yu; Kulig, Kornelia

2016-10-01

This case-based report assessed resting water content and exercise-driven water exchange within a tendon with a history of tendinopathy and compared the response to that of a healthy uninvolved tendon. Case Report. University imaging center. The participant was a 27-year-old female basketball player 39 months following knee trauma. Patellar tendinopathy developed 12 months after the injury episode and was treated with eccentric exercises. Eighteen months from the beginning of the first eccentric training bout, the participant reported full resolution of symptoms and returned to her pre-injury sport participation without symptoms. Eccentric decline squat exercise. Tendon water content obtained from magnetic resonance imaging (MRI). MRI acquired 39 months post-injury demonstrated increased resting water content of the involved tendon (involved: 91.1% vs. uninvolved: 84.6%). Immediately after the eccentric squat maneuver, water content decreased on both involved and uninvolved tendons (involved: 89.5% vs. uninvolved: 83.3%). Elevated resting water content of the involved tendon found in this report may be indicative of reduced tendon stiffness. A similar amount of water content reduction was observed on both sides following mechanical loading, suggesting that the involved tendon may respond to the eccentric exercise similarly to the uninvolved tendon. Future investigations are needed to study the relationships among tendon water exchanges, mechanical properties, patient symptoms, and tissue injuries.