Muscle activity analysis
Bipolar surface electrodes (OE-WS2521; Oisaka, Hiroshima, Japan) were placed on three scapulothoracic muscles (the upper and lower trapezius and the serratus anterior) and a scapulohumeral muscle (deltoid middle) in accordance with previously published standardized methods [The frequency band for the analysis was 1–1000 Hz. Since the measured values are affected by electrode position and skin temperature, photographs of the target site were taken before and after the intervention, and the measurements were performed at the same sites, with the measurements for all muscles obtained simultaneously [