Proprioceptive force-reproduction of the rotator cuff in healthy subjects before and after muscle fatigue

Abstract

OBJECTIVE: To examine the effects of fatigue on force reproduction during internal and external rotation of the shoulder using a single group repeated measure design.

METHODS: Seventeen healthy male subjects who did not regularly compete in overhand sports and had no history of glenohumeral complaints took part in the study. Force reproduction was measured in the dominant shoulder. A target force had to be reproduced in three consecutive trials before and after a fatigue protocol. Maximal voluntary contraction was assessed to determine the target force. Measured data before and after fatigue were analyzed as well as error scores to examine the effect of fatigue.

RESULTS: Repeated-measures analysis of variance revealed a significant influence only in the testing direction. No difference was found with the target value before or after the fatiguing repetitions. The inter-trial intra-class correlation coefficient showed high reliability.

CONCLUSIONS: Force reproduction towards external rotation is more accurate than for internal rotation.