Effects of the Forearm Support Band on Wrist Extensor Muscle Fatigue

Stephen C. Allison, LtJG Damien W. Avery, Jean M. Bryan, 1st Lt Paula T. Knebel, 1st Lt Shane L. Koppenhaver, 1st Lt Terry L. Gebhardt, Ada Kelly

Study Design: A crossover experimental design with repeated measures. Objective: To determine whether the forearm support band alters wrist extensor muscle fatigue. Background: Fatigue of the wrist extensor muscles is thought to be a contributing factor in the development of lateral epicondylitis. The forearm support band is purported to reduce or prevent symptoms of lateral epicondylitis but the mechanism of action is unknown. Methods and Measures: Fifty unimpaired subjects (36 men, 14 women; mean age = 29 ± 6 years) were tested with and without a forearm support band before and after a fatiguing bout of exercise. Peak wrist extension isometric force, peak isometric grip force, and median power spectral frequency for wrist extensor electromyographic activity were measured before and after exercise and with and without the forearm support band. A 2 x 2 repeated measures multivariate analysis of variance was used to analyze the data, followed by univariate analysis of variance and Tukey's multiple comparison tests. Results: Peak wrist extension isometric force, peak grip isometric force, and median power spectral frequency were all reduced after exercise. However, there was a significant reduction in peak grip isometric force and peak wrist extension isometric force values for the with-forearm support band condition (grip force 28%, wrist extension force 26%) compared to the without-forearm support band condition (grip force 18%, wrist extension force 15%). Conclusions: Wearing the forearm support band increased the rate of fatigue in unimpaired individuals. Our findings do not support the premise that wearing the forearm support band reduces muscle fatigue in the wrist extensors. J Orthop Sports Phys Ther. 1999;29(11):677-685. Key Words: forearm support band, lateral epicondylitis, median power spectral frequency

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