| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Life Sciences, The University of Tokyo, Meguro, Tokyo, Japan
2 Department of Integrative Physiology, University of Colorado, Boulder, Colorado, United States
* To whom correspondence should be addressed. E-mail: kouzaki{at}idaten.c.u-tokyo.ac.jp.
Alternate muscle activity between synergist muscles has been demonstrated during low-level sustained contractions (
5% of maximal voluntary contraction force, MVC force). To determine the functional significance of the alternate muscle activity, the association between the frequency of alternate muscle activity during a low-level sustained knee extension and the reduction in knee extension MVC force was studied. Forty-one healthy subjects performed a sustained knee extension at 2.5% MVC force for 1 hr. Before and after the sustained knee extension, MVC force was measured. The surface electromyogram (EMG) was recorded from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles. The frequency of alternate muscle activity for RF-VL, RF-VM, and VL-VM pairs was determined during the sustained contraction. The frequency of alternate muscle activity ranged from 4 to 11 times/hr for RF-VL (7.0 ± 2.0 times/hr) and RF-VM (7.0 ± 1.9 times/hr) pairs, but was only 0 to 2 times hr-1 for the VL-VM pair (0.5 ± 0.7 times/hr). MVC force after the sustained contraction decreased by 14% (P < 0.01) from 573.6 ± 145.2 N to 483.3 ± 130.5 N. The amount of reduction in MVC force was negatively correlated with the frequency of alternate muscle activity for the RF-VL and RF-VM pairs (P < 0.001 and r = 0.65 for both), but not for the VL-VM pair. The results demonstrate that subjects with more frequent alternate muscle activity experience less muscle fatigue. We conclude that the alternate muscle activity between synergist muscles attenuates muscle fatigue.
This article has been cited by other articles:
|
|
 |
|
  Z. A. Riley, S. Baudry, and R. M. Enoka Reflex Inhibition in Human Biceps Brachii Decreases With Practice of a Fatiguing Contraction J Neurophysiol, November 1, 2008; 100(5): 2843 - 2851. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. C. Gandevia Voluntary muscle strength and endurance: 'The mechanism of voluntary muscle fatigue' by Charles Reid Exp Physiol, September 1, 2008; 93(9): 1030 - 1033. [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Taylor and S. C. Gandevia A comparison of central aspects of fatigue in submaximal and maximal voluntary contractions J Appl Physiol, February 1, 2008; 104(2): 542 - 550. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Smith, P. G. Martin, S. C. Gandevia, and J. L. Taylor Sustained contraction at very low forces produces prominent supraspinal fatigue in human elbow flexor muscles J Appl Physiol, August 1, 2007; 103(2): 560 - 568. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
