Force and EMG signal patterns during repeated bouts of concentric or eccentric muscle actions

Tesch, Per A.; Dudley, Gary A.; Duvoisin, Marc R.; Hather, Bruce M.; Harris, R.

doi:10.1111/j.1748-1716.1990.tb08846.x

Cited by 255 publications

(225 citation statements)

References 44 publications

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“…These data are in agreement with others who have demonstrated a 53% decrease in elbow flexors after 100 repeated eccentric actions (Linnamo, Bottas, & Komi, 2000) and repeated actions of the knee extensors (Brown, Child, Day, & Donnelly, 1997;MacIntyre, Reid, Lyster, Szasz, & McKenzie, 1996). However, others have shown that repeated eccentric muscle actions are extremely fatigue resistant despite high force production (Emery et al, 1994;Hortobagyi et al, 1996;Tesch, 1990 It has been suggested that an ICC of 0.88 or above and CV not exceeding ± 6% demonstrates good reliability in isokinetic strength testing (Gleeson & Mercer, 1996). The relative reliability for the WFI and TFI in the current study are lower than this recommended value for both the knee extensors and flexors.…”

Section: Discussionsupporting

confidence: 82%

Reproducibility of an isokinetic eccentric muscle endurance task

Sauret

Croix

Deighan

et al. 2009

European Journal of Sport Science

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Despite the widespread use of isokinetic eccentric muscle endurance protocols, no research has examined the absolute and relative reliability of such tests. The aim of this study was to examine the reliability of an isokinetic eccentric knee muscle endurance task. Fifteen healthy untrained males volunteered to take part in the study and written informed consent was obtained. The procedures received approval from the University Research Ethics Committee. Participants visited the laboratory on three separate occasions: 2 weeks before testing to familiarize them with the experimental procedures, and on two separate occasions, 2 weeks apart and at the same time of day. Isokinetic eccentric knee extension and flexion movements of the dominant limb were performed using a calibrated dynamometer (Biodex System 3). Range of motion during testing was set using voluntary maximal full extension (0 rad) to 1.57 rad of knee flexion and testing was conducted at 1.56 rad × s (1 . Participants performed four maximal efforts to determine maximal peak torque. After 2 min rest, participants completed the all-out endurance test of 50 continuous eccentric repetitions. Data were gravity corrected and windowed to only include constant velocity periods. Repeated-measures analyses of variance were used to examine differences in maximal peak extension and flexion torque and the maximal torque measurement recorded during the endurance test. Absolute and relative reliability of the torque fatigue index, work fatigue index, and total work were assessed through calculation of intra-class correlation coefficients, coefficients of variation, and absolute 95% limits of agreement using the methods described by Bland and Altman (1986). Differences between the strength test and the endurance trial for peak torque were found to be non-significant for both quadriceps (323 vs. 323 N × m) and hamstrings (183 vs. 178 N × m). The intra-class correlation coefficients revealed significant (PB0.05) positive moderate to strong correlations (r00.44Á 0.94) across repeated trials for all parameters except hamstring torque fatigue (P00.11) and hamstring work fatigue index (P 00.08). Coefficients of variation ranged from 6% to 48% and were large for the work fatigue index and torque fatigue index but acceptable for total work for both the extensors and flexors. The 95% limits of agreement indicated systematic bias in repeated trials for both the work fatigue index and torque fatigue index for extensors and flexors, ranging from (3% to (10%, with less fatigue evident in the second test. There was also systematic bias for total work, with more work being performed during the second than the first test for both extensors and flexors. The random error was large for all variables and there was greater random error in the hamstrings compared with the quadriceps. Together with moderate to strong intra-class correlation coefficients and large coefficients of variation, the data suggest that there is small systematic bias in repeated eccentric muscle actions for both the q...

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Section: Discussionsupporting

confidence: 82%

Reproducibility of an isokinetic eccentric muscle endurance task

Sauret

Croix

Deighan

et al. 2009

European Journal of Sport Science

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“…The aEMG and MPF values for all 6 sections were then calculated and used for analysis. Previous authors [42][43][44] reported increased aEMG amplitude and decreased MPF (spectral compression) associated with both isotonic and dynamic muscular contractions in a fatigued state. Third, fatigue has been defined as a reduction in the force-generating capacity of the neuromuscular system that occurs during sustained activity.…”

Section: Data Collectionmentioning

confidence: 99%

Hip-Abductor Fatigue and Single-Leg Landing Mechanics in Women Athletes

Patrek

Kernozek

Willson

et al. 2011

Journal of Athletic Training

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Context: Reduced hip-abductor strength and muscle activation may be associated with altered lower extremity mechanics, which are thought to increase the risk for anterior cruciate ligament injury. However, experimental evidence supporting this relationship is limited. Objective: To examine the changes in single-leg landing mechanics and gluteus medius recruitment that occur after a hip-abductor fatigue protocol. Design: Descriptive laboratory study. Patients or Other Participants: Twenty physically active women (age = 21.0 ± 1.3 years). Intervention(s): Participants were tested before (prefatigue) and after (postfatigue) a hip-abductor fatigue protocol consisting of repetitive side-lying hip abduction. Main Outcome Measure(s): Outcome measures included sagittal-plane and frontal-plane hip and knee kinematics at initial contact and at 60 milliseconds after initial contact during 5 single-leg landings from a height of 40 cm. Peak hip and knee sagittal-plane and frontal-plane joint moments during this time interval were also analyzed. Measures of gluteus medius activation, including latency, peak amplitude, and integrated signal, were recorded. Results: A small (<1°) increase in hip-abduction angle at initial contact and a small (<1°) decrease in knee-abduction (valgus) angle at 60 milliseconds after contact were observed in the postfatigue landing condition. No other kinematic changes were noted for the knee or hip at initial contact or at 60 milliseconds after initial contact. Peak external knee-adduction moment decreased 27% and peak hip adduction moment decreased 24% during the postfatigue landing condition. Gluteus medius activation was delayed after the protocol, but no difference in peak or integrated signal was seen during the landing trials. Conclusions: Changes observed during single-leg landings after hip-abductor fatigue were not generally considered unfavorable to the integrity of the anterior cruciate ligament. Further work may be justified to study the role of hip-abductor activation in protecting the knee during landing.

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“…17 The reduced surface electromyographic (EMG) activity of muscles performing eccentric actions is consistent with the postulated superiority of the mechanical efficiency of these muscle contractions. 18 The intensity of the muscle contraction seems to be an important stimulus for muscle growth and strength development, 19 and, therefore, the greater capacity of eccentric actions to produce force has received the attention of many investigators, who have explored the effectiveness of eccentric exercise regimens in enhancing skeletal muscle performance. 20 Although muscle adaptations observed after training tend to be contractionspecific, 21,22 it is generally accepted that exercise protocols in which eccentric actions are emphasized produce more important gains in strength, 23,24 muscle mass 25,26 and neural adaptations 27,28 than regimens consisting of concentric actions only.…”

Section: Introductionmentioning

confidence: 99%

Eccentric Exercise in Patients with Chronic Health Conditions: A Systematic Review

Roig

Shadgan

Reid³

2008

Physiotherapy Canada

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Purpose: The capacity of eccentric actions to produce muscle hypertrophy, strength gains, and neural adaptations without stressing the cardiopulmonary system has led to the prescription of eccentric training programmes in patients with low tolerance to exercise, such as elders or those with chronic health conditions. The purpose of this systematic review was to analyze the evidence regarding the effectiveness and suitability of eccentric training to restore musculoskeletal function in patients with chronic diseases. Summary of Key Points: Relevant articles were identified from nine databases and from the reference lists of key articles. Articles were assessed to determine level of evidence and scientific rigour. Nine studies met the inclusion criteria. According to Sackett's levels of evidence, 7 studies were graded at level IIb, 1 study at level IV, and the remaining study at level V. Articles were also graded for scientific rigour according to the PEDro scale. One study was rated as high quality, 4 studies were rated as moderate, and 2 studies were graded as poor quality. Conclusions: Eccentric training may be safely used to restore musculoskeletal function in patients with some specific chronic conditions. However, the heterogeneity of diseases makes it very difficult to extrapolate results and to standardize clinical recommendations for adequate implementation of this type of exercise. More studies are needed to establish the potential advantages of eccentric training in chronic conditions. Key Words: atrophy, chronic disease, eccentric training, muscle dysfunction RÉ SUMÉObjectif: La capacité des actions excentriques de produire l'hypertrophie musculaire, une masse osseuse accrue et des adaptations neurales sans exercer de fatigue sur le systè me cardiopulmonaire a mené à la prescription de programmes d'entraînement excentrique chez les patients ayant une tolé rance faible à l'exercice, comme les aîné s ou ceux qui sont atteints d'é tats de santé chroniques. Cette é tude mé thodique a pour but d'analyser les preuves scientifiques concernant l'efficacité et la pertinence de l'entraînement excentrique dans le ré tablissement de la fonction musculosquelettique chez les patients atteints de maladies chroniques. Re´sume´des points cle´s: Des articles pertinents ont é té identifié s à partir de 11 bases de donné es et listes de ré fé rence d'articles clé s. Les articles ont é té é valué s afin de dé terminer le niveau de preuves scientifiques et la rigueur scientifique. Neuf é tudes ont satisfait aux critè res d'inclusion. Selon les niveaux de preuve de Sackett, sept é tudes ont é té classé es au niveau IIb, une é tude au niveau IV et la derniè re é tude au niveau V. Des articles ont aussi é té classé s pour leur rigueur scientifique selon l'é chelle PEDro. Une é tude a é té classé e comme é tant de haute qualité , quatre é tudes comme é tant de qualité moyenne et deux é tudes ont é té classé es comme é tant de qualité mé diocre. Conclusions: L'entraînement excentrique peut ê tre utilisé en toute sé curi...

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Force and EMG signal patterns during repeated bouts of concentric or eccentric muscle actions

Cited by 255 publications

References 44 publications

Reproducibility of an isokinetic eccentric muscle endurance task

Reproducibility of an isokinetic eccentric muscle endurance task

Hip-Abductor Fatigue and Single-Leg Landing Mechanics in Women Athletes

Eccentric Exercise in Patients with Chronic Health Conditions: A Systematic Review

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