AUTHOR=Aranceta-Garza Alejandra , Russo Alessandro , D’Emanuele Samuel , Serafino Francesca , Merletti Roberto 

TITLE=High Density Surface Electromyography Activity of the Lumbar Erector Spinae Muscles and Comfort/Discomfort Assessment in Piano Players: Comparison of Two Chairs

JOURNAL=Frontiers in Physiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.743730

DOI=10.3389/fphys.2021.743730

ISSN=1664-042X

ABSTRACT=<p><bold>Introduction:</bold> At a professional level, pianists have a high prevalence of playing-related musculoskeletal disorders. This exploratory crossover study was carried out to assess and compare quantitatively [using high density surface electromyography (HDsEMG)], and qualitatively (using musculoskeletal questionnaires) the activity of the lumbar erector spinae muscles (ESM) and the comfort/discomfort in 16 pianists sitting on a standard piano stool (SS) and on an alternative chair (A-chair) with lumbar support and a trunk-thigh angle between 105° and 135°.</p><p><bold>Materials and Methods:</bold> The subjects played for 55 min and HDsEMG was recorded for 20 s every 5 min. For the quantitative assessment of the muscle activity, the spatial mean of the root mean square (RMS<sub><italic>ROA</italic></sub>) and the centroid of the region of activity (ROA) of the ESM were compared between the two chairs. For the qualitative assessment, musculoskeletal questionnaire-based scales were used: General Comfort Rating (GCR); Helander and Zhang’s comfort (HZc) and discomfort (HZd); and Body Part Discomfort (BPD).</p><p><bold>Results:</bold> When using the A-chair, 14 out of 16 pianists (87.5%) showed a significantly lower RMS<sub><italic>ROA</italic></sub> on the left and right side (<italic>p</italic> &lt; 0.05). The mixed effects model revealed that both chairs (<italic>F</italic> = 28.21, <italic>p</italic> &lt; 0.001) and sides (<italic>F</italic> = 204.01, <italic>p</italic> &lt; 0.001) contributed to the mean RMS<sub><italic>ROA</italic></sub> variation by subject (<italic>Z</italic> = 2.64, <italic>p</italic> = 0.004). GCR comfort indicated that participants found the A-Chair to be “quite comfortable,” and the SS to be “uncomfortable.” GCR discomfort indicated that the SS caused more numbness than the A-Chair (<italic>p</italic> = 0.05) and indicated the A-Chair to cause more feeling of cramps (<italic>p</italic> = 0.034). No difference was found on HZc (<italic>p</italic> = 0.091) or HZd (<italic>p</italic> = 0.31) between chairs. Female participants (<italic>n</italic> = 9) reported greater comfort when using the A-Chair than the SS (<italic>F</italic> = 7.09, <italic>p</italic> = 0.01) with respect to males. No differences between chairs were indicated by the BPD assessment.</p><p><bold>Conclusion:</bold> It is concluded that using a chair with lumbar support, such as the A-chair, will provide greater comfort, less exertion of the ESM and less discomfort than the standard piano stool.</p>