Background: The great variability of viola dimensions is known. Contrary to the violin, a lack of scientific knowledge remains on how dimensions, positioning, and biomechanical parameters contribute to the high incidence of medical complaints in violists. Aims: This project investigated how an instrument’s dimensions affect objective and subjective levels of muscular effort in a player’s left hand and arm, together with the instrument’s position and biomechanical parameters. Methods: In a laboratory setting, a quantitative, intra-individual comparison between two violas, V1 and V4, predefined in dimensions and positions, and the participants’ own instrument was carried out. Muscle activation (EMG) and perceived effort (BORG) of 31 violists (15 m/16w, mean age 24.8 years, SD = 3.6) were recorded while playing a 16-s tune. Measurements with instruments V1 and V4 were conducted in standardized positions (A1, A2, B1, B2) without and with the players’ own instruments with ergonomic aids. EMG/BORG data were associated with individual biomechanical parameters (BHM). Results: Positional changes of the instruments’ longitudinal and lateral axes significantly affect target parameter values. Between the extreme positions A1 vs. B2, the mean delta for EMG decreased 29% relative to A1 (p < 0.001), and for perceived effort (BORG) 28% (p < 0.001). Comparing the instruments V1 and V4 shows significant differences for BORG (p < 0.05) but not for EMG at this data aggregation level. A key finding for biomechanics is the negative correlation between all arm length parameters with EMG and BORG (both p < 0.001). Conclusion: Results for the viola reconfirm that instrument positioning affects muscle activation and subjectively perceived effort, highly significantly. This expands possibilities to deduce individualized ergonomic solutions, benefiting playing posture, practicing, and performance. The prevention and solution of Playing-Related Musculoskeletal Disorders (PRMDs) could be facilitated, permitting this group of musicians to thrive. Future sub-analysis aims to identify instrument build effects at the single-muscle level and for the hand positions under test. Further research in real-life settings will be needed to understand how longer durations of playing affect the same target parameters.
Margulies et al. (Thu,) studied this question.