Abstract
The purpose of this study was to clarify the effects of swing training simulating hammer throw on the morphology of the lateral abdominal muscles and swing velocity. Seventeen male baseball players (Age 19.5 ± 1.5 yrs, Height 169.8 ± 4.0 cm, Body mass 66.9 ± 6.4 kg）participated in this study. In this study, the subjects were divided into two groups: eight subjects who additionally worked on hammer swing in addition to normal training (Tr) and nine subjects who only worked on normal training (Con). Swing speed was measured using a bat swing analysis system consisting of an inertial sensor unit, an attachment, and a smartphone application. Muscle thickness of the lateral abdominal muscles (external oblique, internal oblique, and transversus) on the side of the stepping leg was measured. Hammer swing training was performed for 4 weeks. The results showed that there was an interaction between the Tr group and the Con group in terms of swing speed, and only the Tr group showed a significant increase in swing speed. In conclusion, it was obvious that the swing speed was improved by the hammer swing training conducted in this study.
