(47) EFFECT OF THE OFFSEASON ON BODY COMPOSITION AND STRENGTH IN DIVISION I COLLEGIATE BASEBALL PLAYERS

Purpose: To investigate the effect of the offseason on body composition and lower and upper body strength in collegiate baseball players.

Methods: Forty-two (21 pitchers and 21 position players) Division I baseball players (age = 20.4 ± 1.6 years, height = 182.6 ± 7.1 cm) participated in this study. They performed the same resistance training program, but conditioned differently over the offseason. Body composition was determined by bioelectrical impedance analysis (InBody 770) according to the manufacturer specifications at two time points: beginning of the offseason (September) and end of the offseason (December). Body mass (BM), fat mass (FM), percent body fat (%BF), lean body mass (LBM), skeletal muscle mass (SMM), and dry lean mass (DLM) were recorded. Lower and upper body strength variables, one repetition maximum (1RM) back squat, bench press, and 1-arm row, were measured two times: beginning of the offseason and end of the offseason. Eight 2x2 (position x time) repeated measures ANOVAs were used to analyze changes in body composition and strength variables. Changes in body composition and strength variables between times points were calculated and relationships between these variables were analyzed with Pearson product-moment correlations. Statistical significance was set at 0.05 and the data were analyzed using SPSS 22.0.

Results: For body composition, significant differences (p < 0.05) were found for pitchers for FM, %BF, LBM, SMM, and DLM from the beginning to the end of the offseason. There were no significant differences for body composition for position players. For strength variables, both pitchers and position players had significant differences for 1RM back squat, bench press, and 1-arm row. Pitchers demonstrated a significantly greater improvement in back squat than position players. Significant correlations in changes in body composition variables were found for pitchers between BM and FM (r = 0.643), %BF (r = 0.486), LBM (r = 0.710), SMM (r = 0.698), and DLM (r = 0.688); FM and %BF (r = 0.981); LBM and SMM (r = 0.980) and DLM (r = 0.962); SMM and DLM (r = 0.967). Significant correlations in changes in body composition variables were found for position players between BM and FM (r = 0.569), %BF (r = 0.454), LBM (r = 0.671), SMM (r = 0.589), and DLM (r = 0.605); FM and %BF (r = 0.984); LBM and SMM (r = 0.982) and DLM (r = 0.954); SMM and DLM (r = 0.960). There were no relationships between changes in body composition and changes in strength.

Conclusions: Pitchers experienced a decrease in FM and %BF and an increase in LBM, SMM, and DLM over the offseason. Body composition of position players did not change over the course of the offseason. Lower and upper body strength increased for both pitchers and position players. Pitchers had a significantly greater improvement in 1RM back squat than position players. Upper body strength improvements were similar for pitchers and position players. PRACTICAL APPLICATIONS: Offseason strength and conditioning, practices, and intrasquad games can impact body composition and strength. It is important for college players to attempt to improve strength and maintain or gain LBM, SMM, and DLM over the offseason as it is challenging to maintain body composition and lower and upper body strength over a 3–4-month college baseball season. 

Acknowledgements: We would like to thank the Louisiana Tech baseball players for volunteering to be in this study and Austin Reedy, Chris Watson, Elise Bordlee, Trenton Miller, Sam Briehn, and Wyatt Coppola for assisting with data collection.