Lower extremity kinematic and kinetic factors associated with bat speed at ball contact during the baseball swing

Lower extremity kinematic and kinetic factors associated with bat speed at ball contact during the baseball swing 

Orishimo, K. F., Kremenic, I. J., Modica Jr, E., Fukunaga, T., McHugh, M. P., & Bharam, S. (2023). Lower extremity kinematic and kinetic factors associated with bat speed at ball contact during the baseball swing. Sports Biomechanics, 1-12.

Summary:

The study examined the biomechanical factors influencing bat speed during a baseball swing in collegiate players. Researchers aimed to identify which kinematic (movement-based) and kinetic (force-based) variables correlate with the linear bat speed at the moment of ball contact. By analyzing the swings of 20 players as they hit from a tee, they recorded motion via a capture system and measured ground reaction forces using force plates. The average bat speed was noted at 30 m/s, with significant correlations found between bat speed and various ground reaction forces generated by the lead foot. 

Specifically, the peak vertical ground reaction force showed a strong relationship (r = 0.622, P = 0.001) with bat speed, as did the peak anterior/posterior force and resultant force. The authors highlighted the lead leg's critical role in generating and transferring force through the kinetic chain, emphasizing that effective training should focus on enhancing lower extremity strength and sport-specific mechanics. Kinematic factors, including peak pelvis and trunk velocities and hip-shoulder separation, showed negligible correlations to bat speed, indicating that ground forces are more decisive than segmental velocities in this context. 

The timing of various kinematic and kinetic events was analyzed, revealing that key moments such as peak lead knee extension and hip-shoulder separation occurred significantly earlier than peak forces generated, thus establishing a sequence critical for optimizing hitting performance. The authors suggest incorporating closed kinetic chain exercises in training, such as squats and specific hitting drills, aiming to improve lower extremity kinetics. Future studies are encouraged to explore how such training impacts bat speed and mechanical performance during swings. While the study’s findings may guide coaches and players to enhance batting skills, limitations were noted, including the exclusive focus on collegiate players and the use of a tee instead of live pitching, which could affect the generalizability of the results. Overall, the research provides valuable insights into optimizing bat speed through biomechanical factors.

Article link