RESUMEN
Musculoskeletal complaints are highly prevalent in clarinetists and are related to high arm load while playing. It is hypothesized that postural exercise therapy may be used to adapt muscle activity patterns while playing and thus contribute to better sound quality. The goal of the present study was to investigate the relationship between body posture, muscle activity, and sound quality in clarinetists while playing the instrument in two different postures, their habitual sitting posture (control, CO) vs an experimental sitting posture (EXP) based on Mensendieck postural exercise therapy, method Samama. Twenty healthy professional and student clarinet players, aged 18-60 years, were included in this cross-sectional study. Participants played a 60-second musical excerpt in CO, followed by instruction on the EXP body posture, and then played in the EXP condition. Two-dimensional goniometric analysis was used to calculate body posture; muscle activity was measured bilaterally using surface electromyography. In EXP, a significantly smaller low thoracic angle, smaller high thoracic angle, and larger pelvic tilt angle (all p<0.001) were found. EMG results indicated that the left and right erector spinae L3 and left and right lower trapezius were more active in EXP compared to CO, whereas left upper trapezius and right brachioradialis were less active in EXP than CO. Most participants experienced better sound quality in EXP, whereas blinded experts found no consistent pattern between body posture and sound quality. To conclude, it seems that postural exercise therapy may change muscle activity patterns. By increasing stability, a decrease in activity of the upper extremity muscles can be induced.