Effects of fatigue on the series elastic component of human muscle

Vigreux, B.; Cnockaert, J. C.; Pertuzon, E

doi:10.1007/bf00421196

Cited by 37 publications

(33 citation statements)

References 12 publications

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“…While our pre-fatigue values do not support this contention (further suggesting reflex induced EMD mechanisms may be different from voluntary contractions), it is possible that fatigue may interact with these factors to differentially influence the compliance of the series elastic component. Increased muscle compliance following fatigue has been previously demonstrated by Vigreux et al [55].…”

Section: Series Elastic Componentmentioning

confidence: 80%

The differential effects of fatigue on reflex response timing and amplitude in males and females

Moore

Drouin

Gansneder

et al. 2002

Journal of Electromyography and Kinesiology

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SJ. The differential effects of fatigue on reflex response timing and amplitude in males and females. Journal of Electromyography and Kinesiology. 2002; 12:351-360 Abstract:We examined the effects of fatigue on patellar tendon reflex responses in males and females. A spring-loaded reflex hammer elicited a standardized tendon tap with the knee positioned in an isokinetic dynamometer and flexed to 85°. We recorded vastus lateralis activity (SEMG) and knee extension force production at the distal tibia (force transducer). Reflex trials were performed before and after (immediate, 2, 4, and 6 min) an isokinetic fatigue protocol to 50% MVC (90°/s). For each event, pre-motor time (PMT), electromechanical delay (EMD), and total motor time (TMT) were obtained, as well as EMG amplitude (EMGamp), time to peak EMG (EMGtpk), peak force amplitude (Famp), time to peak force (Ftpk), EMG:force ratio (E:F), and rate of force production (Frate=N/ms). TMT increased significantly in females following fatigue, while males showed no change. The increased TMT was due to an increased EMD with fatigue, while PMT was unaffected. EMGamp and Famp were somewhat diminished in females yet significantly augmented in males following fatigue, likely accounting for the differential changes in EMD noted. Results suggest males and females may respond differently to isokinetic fatigue, with males having a greater capacity to compensate for contraction force failure when responding to mechanical perturbations.

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Section: Series Elastic Componentmentioning

confidence: 80%

The differential effects of fatigue on reflex response timing and amplitude in males and females

Moore

Drouin

Gansneder

et al. 2002

Journal of Electromyography and Kinesiology

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“…It has also been shown that the contractile mechanisms of a muscle, especially the series elastic component, may be altered during an exercise (Vigreux et al 1989) and it is assumed that the contractile response of a muscle depends to a great extent on the exercise activation (Rassier and MacIntosh 2000). A brief period of repetitive stimulation results in enhanced contractile response (potentiation) while continued stimulation results in impairment or attenuated response (fatigue) (Rassier and MacIntosh 2000).…”

Section: Discussionmentioning

confidence: 99%

Acute changes in muscle activation and leg extension performance after different running exercises in elite long distance runners

Vuorimaa¹,

Virlander

Kurkilahti³

et al. 2005

Eur J Appl Physiol

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This study investigated acute changes in muscle activation and muscular power performance after three different running exercises in elite long-distance runners. Twenty-two nationally and internationally ranked long-distance runners performed first an incremental treadmill running test until exhaustion (MR) and then 40 min continuous (TR) and intermittent (2 min run/2 min rest) (IR) running exercises at an intensity of 80 and 100% of the velocity associated with VO(2max), respectively. Muscle activation and muscular power performance tests (counter-movement jumps, CMJ, and a set of ten maximal half squats from the static starting position with an extra load of 35% of the subjects, one repetition maximum) were performed before and immediately after the runs. The average mechanical power (P) of the half squats was calculated and the root mean square electromyogram (EMGrms) from the vastus lateralis, vastus medialis, gastrocnemius and biceps femoris muscles was recorded simultaneously during the half squat performances. The results showed an acute exercise-induced increase in P (ANOVA time effect, P = 0.000) together with a reduction in EMGrms of the knee extensor muscles (ANOVA time effect, P = 0.000). However, mechanical P expressed as a relative change within the set decreased after MR. In TR the improvement in P correlated positively with the maximal running performance of the runners (P < 0.05), while in IR it correlated negatively (P < 0.05). Jumping performance was significantly enhanced after each run (P < 0.001, for all) and the improvement correlated negatively with the maximal sprinting speed and maximal jumping height of the runners (P < 0.01, for all). It is concluded that in elite long distance runners an intensive prolonged running exercise reduces the surface EMG of the knee extensor muscles, and may lead to a different coordination strategy in leg extension exercises performed into the vertical direction. After continuous type of running the power improvement correlates positively with maximal endurance running capacity, whereas after intermittent type of running it correlates negatively.

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“…For "ramp contractions", once any value (corresponding to a 1 mm ϫ 1 mm subregion) within the ROI reached 266 kPa, there was no further analysis at that force and any higher force. For experiment I, the EMG-RMS/torque and shear elastic modulus/ torque relationships obtained for "ramp contractions" were fitted to a linear model (4,34) to calculate slope (a) and y-intercept (b). To assess the fit for the first ramp, the coefficient of determination (R 2 ) and the error of estimation [i.e., RMS deviation (RMSdevR1)] were calculated for both EMG and SSI measurements (4).…”

Section: Index Of Muscle Force During a Fatiguing Task • Bouillard K mentioning

confidence: 99%

“…Thus one would expect that the alteration of motor unit discharge characteristics associated with fatigue does not influence the shear elastic modulus. However, putative changes in mechanical properties of muscle occurring with fatigue (31,34,35) could preclude the ability to provide an index of muscle force during a fatiguing contraction.…”

mentioning

confidence: 99%

Shear elastic modulus can be used to estimate an index of individual muscle force during a submaximal isometric fatiguing contraction

Bouillard

Hug

Guével

et al. 2012

Journal of Applied Physiology

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The present study was designed to determine whether fatigue alters the ability to estimate an index of individual muscle force from shear elastic modulus measurements ( experiment I), and to test the ability of this technique to highlight changes in load sharing within a redundant muscle group during an isometric fatiguing task ( experiment II). Twelve subjects participated in experiment I, which consisted of smooth linear torque ramps from 0 to 80% of maximal voluntary contraction (MVC) performed before and after an isometric fatigue protocol, beginning at 40% of MVC and stopped when the force production dropped below 30% of MVC. Although the relationships between modulus and torque were very similar for pre- and postfatigue [root mean square deviation (RMSdeviation) = 3.7 ± 2.6% of MVC], the relationships between electromyography activity level and torque were greatly altered by fatigue (RMSdeviation = 10.3 ± 2.6% of MVC). During the fatiguing contraction, shear elastic modulus provided a significantly lower RMSdeviation between measured torque and estimated torque than electromyography activity level (5.7 ± 0.9 vs. 15.3 ± 3.8% of MVC). Experiment II performed with eight participants consisted of an isometric knee extension at 25% of MVC sustained until exhaustion. Opposite changes in shear elastic modulus were observed between synergists (vastus medialis, vastus lateralis, and rectus femoris) of some participants, reflecting changes in load sharing. In conclusion, despite the fact that we did not directly estimate muscle force (in Newtons), this is the first demonstration of an experimental technique to accurately quantify relative changes in force in an individual human muscle during a fatiguing contraction.

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Effects of fatigue on the series elastic component of human muscle

Cited by 37 publications

References 12 publications

The differential effects of fatigue on reflex response timing and amplitude in males and females

The differential effects of fatigue on reflex response timing and amplitude in males and females

Acute changes in muscle activation and leg extension performance after different running exercises in elite long distance runners

Shear elastic modulus can be used to estimate an index of individual muscle force during a submaximal isometric fatiguing contraction

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