Correlation Between Muscle Strength, Swing Speed, Batting Statistics, and Body Composition Parameters in High School Baseball Players: A Retrospective Observational Study

Abstract Suzuki, K, Mizoguchi, Y, Kimura, F, Fujisaki, K, Yokoyama, D, Hall, T, and Akasaka, K. Correlation between muscle strength, swing speed, batting statistics, and body composition parameters in high school baseball players: a retrospective observational study. J Strength Cond Res 39(2): e135–e141, 2025—Body composition has emerged as a pivotal factor influencing baseball player performance. The purpose of this study was to examine the relationships between muscle strength, swing speed, batting statistics, and body composition in high school baseball players. This retrospective study evaluated 29 high school baseball players included critical parameters related to body composition (body fat percentage, lean body mass [LBM], fat mass index [FMI], and fat-free mass index [FFMI]), muscle strength (bench press, squat, deadlift), batting statistics (batting average, on-base percentage, slugging percentage, on-base plus slugging), and swing speed. These metrics were gathered using a body composition analyzer (Omron HBF-701; Omron Healthcare Co., Kyoto, Japan). After the correlation analysis with body composition, a subsequent multivariate analysis was conducted. Multivariate regression analysis identified LBM (p < 0.05, p < 0.01) as a significant predictor for bench press and swing speed, FFMI for squat (p < 0.01), and FMI for deadlift (p < 0.05). No significant association was found between body composition and batting statistics. Lean body mass has been identified as an important contributing factor to swing speed, suggesting the need for body composition management among high school baseball players and coaches to enhance performance and functionality. However, no association was found between batting statistics and body composition. Therefore, it is suggested that high school baseball players prioritize the development of technical skills over swing speed and muscle strength to improve batting statistics.