The potential relevance of altered muscle activity and fatigue in the development of performance-related musculoskeletal injuries in high string musicians

Background: Muscle fatigue has been reported as a risk factor for the development of performance-related musculoskeletal disorders (PRMD) in musicians. However, little research exists to support this claim. The aim of this study was to investigate whether changes occur in muscle activity patterns during high string performance over a prolonged playing period, and whether this is influenced by PRMD. Methods: High string musicians were divided into a PRMD and a non-PRMD group. They played a chromatic scale pre and post and a self-chosen “hard” (Borg scale 16-17) piece of music for one hour. Electromyography data recorded from arm, shoulder and trunk muscles was analyzed: the amplitude to measure muscle activity characteristics and the lower frequency to measure muscle fatigue. Differences between and within groups and the frequency spectrum were analyzed using linear mixed models. Results: Fifteen musicians participated (7 PRMD: 22.8 years, 2 male/5 female and 8 non-PRMD: 34.3 years, 2 male/6 female). Changes in muscle activation patterns were observed between and within both groups, however changes varied significantly depending on group affiliation. Significant low frequency spectrum changes between groups were observed in overall muscles of the right arm (p=0.04) and left forearm flexors (p=0.05) following one hour of playing. Conclusions: Muscle activity and frequency spectrum shifts differ in high string musicians with and without PRMD, suggesting possible differential muscle fatigue effects between the groups