- 九州共立大学研究紀要 = Study journal of Kyushu Kyoritsu University (ISSN:21860483)
- vol.5, no.1, pp.23-28, 2014-09-30
The purpose of this study was to investigate the muscle activation levels of the hip muscles duringpitching motion as ball speed was increased. Six college baseball pitchers were participated in thisstudy. Surface electromyography data were recorded in pivot leg from 6 muscles : adductor longus(AL), gracilis (GR), adductor magnus (AM), rectus femoris (RF) , biceps femoris (BF) and gluteus medius(GM). The pitching motion was divided into 5 distinct phases: wind-up, early cocking, late cocking,acceleration, follow-through. The results demonstrated that high level muscle activity (greater than 40%maximal voluntary contraction) was found in GM during early cocking phase, and in AL, GR, AM andBF during late cocking phase, and in AL, GR and BF during acceleration phase. Then, the activity levelof the hip muscles in the slow ball pitching and fast ball pitching was compared. Significantly highermuscle activity was showed in fast ball pitching in AL, GM, and BF during early cocking phase, in BFand AL during late cocking phase, and in AL, GM, and RF during acceleration phase. The findings fromthis study indicate that high muscle activity have been shown in the abductor of the hip joint duringearly cocking phase that produce translational movement, and high muscle activity have been shown inthe adductor and extensor of the hip joint during late cocking phase and acceleration phase that producerotational movement.