Mookerjee, S., Strohecker, K. A., Cole, P., & Armillei, R. J. (2002). Comparison of EMG activity of the elbow flexors during a supported versus unsupported isotonic arm curl. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 703.

Ss (M = 6; F = 2) performed a one-repetition maximum (1 RM) test on each of a supported and unsupported two-handed curl. The involvement of the biceps brachii, brachialis, brachioradialis, and pronator teres were measured.

There were significant differences in 1 RM between the exercises (unsupported was ~20% greater). Muscle activation levels of the four muscles were significantly greater during the concentric (flexion) phase of the action than during the eccentric (extension) phase. There were no significant differences between the patterns of muscle activation in the two exercises. [The use of a barbell could have dictated how and restricted the manner in which the muscles were involved.]

Implication. When using a piece of restricting equipment, repetitions of and slight variations in a resistance exercise do not alter the pattern of muscle activation.

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