The Behaviour of Coactive Muscles During Fatigue

Psek, J. A.; Cafarelli, E.

doi:10.1249/00005768-199205001-00545

Cited by 8 publications

(22 citation statements)

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“…This suggests that coactivation is controlled with a central programme. It is also known that there is an increase in coactivation during fatiguing isometric contractions (Psek & Cafarelli, 1993). This increase in opposing force detracts from net force production and contributes to fatigue.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, contractions performed without visual feedback were necessary in order to avoid suppression of the TVR. Force Subjects were seated in a leg dynamometer which had been modified to allow access to the hamstrings (Psek & Cafarelli, 1993). The chair was tilted backward 45 deg with the subjects' knees flexed at 90 deg and the hips restrained with a seat belt.…”

Section: Test Contractionsmentioning

confidence: 99%

“…Moreover, the ratio is maintained during progressive fatigue even though agonist drive increases steadily (Psek & Cafarelli, 1993 Nielsen & Kagamihara (1993) (Nielsen & Kagamihara, 1992). This uncoupling would ensure a high excitability of both motoneuron pools and hence the development of force in both muscles (Nielsen & Kagamihara, 1992).…”

Section: Coactivation During Progressive Fatiguementioning

confidence: 99%

“…Sherrington also discussed the phenomenon of double reciprocal inhibition in which antagonist muscle pairs are simultaneously active (Tyler & Hutton, 1986). This is now referred to as coactivation and in most voluntary contractions it produces force that acts in opposition to the agonist (Patton & Mortensen, 1970;Solomanow, Baratta, Zhou & D'Ambrosia, 1988;Carolan & Cafarelli, 1992;Psek & Cafarelli, 1993). The central nervous system (CNS) shifts between reciprocal inhibition and coactivation of antagonist muscle, depending on the circumstances (Brooks, 1986).…”

mentioning

confidence: 99%

“…This reduction in opposing force contributes to the small but significant increase in extension maximal voluntary contraction (MVC) after 1 week of training (Carolan & Cafarelli, 1992). Similarly, during progressive fatigue of the knee extensors, antagonist coactivation increases and contributes to the loss of extensor force-producing capacity (Psek & Cafarelli, 1993). The idea that coactivation is governed by a central descending common drive was first presented by DeLuca & Mambrito (1987).…”

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confidence: 99%

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Effect of vibration on antagonist muscle coactivation during progressive fatigue in humans.

Rothmuller

Cafarelli

1995

The Journal of Physiology

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1. Biceps femoris antagonist coactivation increases during progressive fatigue. Our purpose was to determine if the mechanism that increases coactivation during fatigue is susceptible to vibration. Vibration drives alpha‐motoneurons via the Ia loop, producing force without descending motor drive, and thus uncoupling antagonist and agonist activation. Evidence that vibration increases coactivation disproportionately from its ‘common drive’ would suggest the possibility that some of the effects of fatigue are mediated through a segmental reflex loop. 2. Ten male subjects performed repeated maximal voluntary isometric contractions (MVCs) of the knee extensors of one leg. Paired submaximal test contractions (50% of MVC), without visual feedback, were performed when MVC reached 85, 70 and then 50% of its initial value. Vibration was applied to the patellar tendon during one test contraction in each pair. 3. Vibration reduced test contraction force below control values. However, coactivation increased at the same rate in both conditions. Biceps femoris coactivation was greater during vibration, but did not change during fatigue in either condition. 4. Our observations suggest that agonist‐antagonist muscle pairs are controlled as a single motor unit pool by a common central drive. Vibrating the agonist increases antagonist coactivity, but does not alter the rate at which coactivation increases during fatigue. This supports the idea that agonist coactivation is controlled by a central mechanism.

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Section: Discussionmentioning

confidence: 99%

Section: Test Contractionsmentioning

confidence: 99%

Section: Coactivation During Progressive Fatiguementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of vibration on antagonist muscle coactivation during progressive fatigue in humans.

Rothmuller

Cafarelli

1995

The Journal of Physiology

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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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Behaviour of the human gastrocnemius muscle architecture during submaximal isometric fatigue

Mademli

Arampatzis

2005

Eur J Appl Physiol

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The purpose of this study was to examine whether the human gastrocnemius medialis (GM) fascicle length and pennation angle alter during a sustained submaximal isometric plantar flexion. Fourteen male subjects performed maximal voluntary plantar flexions (MVC) on a dynamometer before and after a fatiguing task. This task consisted of a sustained submaximal isometric fatiguing contraction (40% MVC) until failure to hold the defined moment. Ultrasonography was used to visualise the muscle belly of the GM. Leg kinematics were recorded (120 Hz) to calculate the joint moment using inverse dynamics. The exerted moments and the EMG signals from GM and lateralis, soleus and tibialis anterior were measured at 1,080 Hz. The root mean square (RMS) of the EMG signal of the three triceps surae muscles increased significantly (P < or = 0.05) between 17% and 28% with fatigue. Further, the fascicle length of the GM significantly decreased from 47.1 +/- 8.0 mm at the beginning to 41.8 +/- 6.7 mm at the end of fatigue and the pennation angle increased from 23.5 +/- 4.1 degrees to 26.3 +/- 2.2 degrees (P < or = 0.05). The changes in fascicle length and pennation angle of the GM during the contraction can influence the force potential of the muscle due to the force-length relationship and the force transmission to the tendon. This provides evidence on that an additional mechanical mechanism, namely tendon creep, can contribute to the increase in the EMG activity of the GM during submaximal isometric sustained contractions.

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The Behaviour of Coactive Muscles During Fatigue

Cited by 8 publications

References 0 publications

Effect of vibration on antagonist muscle coactivation during progressive fatigue in humans.

Effect of vibration on antagonist muscle coactivation during progressive fatigue in humans.

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

Behaviour of the human gastrocnemius muscle architecture during submaximal isometric fatigue

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