出版社：Japan Society of Physical Education, Health and Sport Sciences
摘要：The purpose of this study was to clarify the physical fitness factors related to ball velocity in terms of playing position among junior high school (JHS) or high school (HS) baseball players during the growth period. The subjects were 78 pitchers (JHS: n = 38, HS: n = 40) and 216 fielders (JHS: n = 121, HS: n = 95). The measured parameters were body height, body weight, ball velocity, hand grip force, back extension force (BET), height/power by counter movement jump, and distance of the side (SMT) and back medicine ball throw (BMT). The pitchers pitched a ball from a temporary mound and the fielders threw a ball from flat ground. Ball velocity was measured using a radar gun. Multiple regression analysis with the stepwise method was used for statistical analysis. For this analysis, ball velocity was the dependent variable, and items of the physical fitness test and physical measurement comprised the independent variables. This analysis selected SMT and BET as predictors of the pitchers’ ball velocity, and the contribution ratio of ball velocity was 65.8%. When BMT and BET were selected as predictors of the fielders’ ball velocity, the contribution ratio of ball velocity was 62.1%. These results indicate that the relationship between ball velocity and force/power output-generating capacity differ between the motion for a given position and/or the required ability. These findings indicate that coaches for growing adolescent baseball players should assess directionality and the effects of training, as they may explain why ball velocity contributes more than 60% to the medicine ball throw distance and BET.
