MacGillis, C. J., Hunter, S. K., Lepers, R., & Enoka, R. M. (2002). Activation differs among the elbow flexor muscles during a submaximal fatiguing contraction. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 656.

A comparison was made of the endurance time and electromyographic (EMG) activity of the elbow flexor muscles when supporting an inertial load performing an isometric contraction. Ss of both genders (N = 24) performed an isometric contraction against a load of 20% of maximal contraction. Maximum voluntary contractions were performed immediately before and after the experimental task.

The three trials were similar in endurance time and maximum voluntary force decline. There were variable patterns of activation between the muscles involved in the exercise. Thus, no single muscle within a group involved in a fatiguing exercise is representative of the involvement of the other muscles in the exercised group.

Implication. Muscles within an exercising group are not involved in the activity in a similar manner nor do they fatigue in similar fashions.

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