The acute effects of a rotational medicine ball throw exercise on baseball pitching biomechanics

Abstract

The ability to throw at higher velocities with proper mechanics is very advantageous for baseball pitchers to increase performance and decrease injury risk. Pitching utilizes the movement of energy through the kinetic chain, wherein momentum is generated by the proximal core segments of the body and transferred to the distal segments of the throwing shoulder and elbow to produce ball velocity. Medicine ball throws (MBT) have been used as a training method for rotational throwing and striking athletes to improve core strength and power. Rotational MBT are sport-specific for baseball pitching because of the similar explosive sequential muscle activation of the pelvis, torso, and arms. The purpose of this study was to investigate the effects of a side-rotational MBT exercise on pitching biomechanics and ball velocity when performed immediately prior to pitching as a method of post-activation potentiation (PAP). High school, college, and professional aged pitchers (n = 6, age 19.5 ± 3.6 years) were randomly assigned to MBT and control (CON) groups. Both groups threw five pre-trial and five post-trial maximal effort fastballs, with the MBT group performing one set of six side-rotational MBT at maximum effort in between the pre and post-trials while the CON group rested. All pitching trials were recorded by a three-dimensional motion capture system at 240 Hz, from which five temporal, four kinematic, and three kinetic variables were calculated. A 2 x 2 mixed ANOVA for each dependent variable was used for comparisons between and within groups. There were significant interactions between groups and time for peak trunk rotational velocity (p = .049), peak elbow extension velocity (p = .014), and maximum external rotation torque (p = .042). These results may warrant further research into MBT as a method for warming up and eliciting a PAP response for pitching.