Identification of physical characteristics associated with swing velocity of batting in youth baseball players

BACKGROUND: Identifying the characteristics of physical function and muscle strength related to swing velocity is necessary for improving batting performance. The aim of this study was to identify the factors related to swing velocity in youth baseball players. METHODS: 191 youth baseball players aged 7-13 years old participated and were divided into the Tee Ball (<9.5 years) and Major (≥9.5 years) divisions. We measured the swing velocity for batting performance, medicine ball (MB) back throw and modified star excursion balance test (SEBT) for physical function, and hip muscle torque for lower extremity muscle strength. RESULTS: Height and MB back throw (β=0.403 and 0.380) for physical function (R2=0.646), and height and internal rotation (IR) torque of the step leg (β=0.620 and 0.216) in lower extremity muscle strength (R2=0.616) were all extracted as related independents for the multiple regression analysis on swing velocity in all subjects. Additionally, height, MB back throw and modified SEBT in the pivot leg (β=0.420, 0.324 and 0.218) for the major division (R2=0.579), and IR torque of the pivot leg and step leg (β=0.555 and 0.525) for the tee ball division (R2=0.568) were selected. CONCLUSIONS: Swing velocity was related to height, MB back throws on physical function, and IR torque of the stepping leg in lower extremity muscle strength in youth baseball players. Therefore, the explosive power and strength for stopping the body opposite to the hitting direction are considered necessary to increase the swing velocity.