Abstract des Autors

This study investigated modular control during Japanese archery and compared the modules between an elite group (level 4 or above in the Kyudo proficiency test) and a novice group (level 3 or lower) in a pilot study. Muscle activities were recorded on both sides of the rectus abdominis, external oblique (EO), internal oblique/transversus abdominis (IO/TrA) and erector spinae (ES) using surface electromyography. Modules were extracted from electromyography signals using non-negative matrix factorization (NMF). According to the results of NMF analysis, two modules explained the electromyographic activity of all muscles. One module was the same between groups and consisted mainly of data from the ES muscle during the first half of the shooting sequence. It is considered a means of stabilizing the trunk to keep it from moving during shoulder flexion and abduction motion. The other module was different between groups, although the activation timing was similar. The module in the elite group mainly engaged IO/TrA activity. In contrast, the module in the novice group mainly comprised EO activity. The IO/TrA fixes the trunk during upper limb movement in the upright position. This result suggests that IO/TrA activity during the shooting sequence may influence performance.