The positive correlation between trunk, leg, and shoulder strength and linear bat velocity at different ball locations during the baseball swing in adult baseball hitters

BACKGROUND: Strength of body segments and bat velocity during the baseball swing have been described as positively related, but the relative importance of each body segment's strength and the effect of ball location in the strike zone have not been examined. OBJECTIVE: To identify the correlation between the strength of different body segments along the kinetic chain and bat velocity with the ball placed at different locations within the strike zone, and to determine which segment's strength best predicts bat velocity. METHODS: Nineteen adult baseball hitters were assessed for bat velocity at five ball locations and tested for isokinetic trunk, shoulder, and knee strength. Strength variables significantly correlated to bat velocity were used in backward stepping linear regression. RESULTS: Trunk rotation strength was significantly correlated to bat velocity for all ball locations. Knee strength was significant for all locations except for high inside. Shoulder strength was significant only with the ball outside. Based on regression analysis, trunk rotation strength was the only significant predictor. CONCLUSIONS: Significant correlations between chosen strength variables and bat velocity were identified. Only trunk rotation strength was a significant predictor of bat velocity. Baseball hitters seeking greater bat velocity may benefit from targeting trunk rotation strength.