(5) THE IMPACT OF A COMPETITIVE SEASON ON JUMPING PERFORMANCE AND BODY COMPOSITION IN D1 MALE VOLLEYBALL ATHLETES

Purpose: Evaluate the impact of the NCAA collegiate volleyball season on jumping performance and body composition. Methods: Seventeen NCAA Division I male volleyball players participated in this 16-week longitudinal study. Participants were tested 3 times: end of the preparation period (PP) (Week 0), bye-week (BW) (Week 10), and conclusion of competitive period (CP) (Week 17). Jump performances were measured using photocells. Jump tests included attack jump, step approach jump, and block jump. Lower body power index (LBPI) was measured by four repeated vertical jumps. Body composition was analyzed using Dual-energy X-ray absorptiometry (DXA). Measures of interest were lean tissue mass, fat tissue percentage, LBPI, jump height. A series repeated measure ANOVAs were used for statistical analyses. Results: Fat tissue percentage changes over the course of the season (F = 10.242; p < 0.001; ηp2 = 0.390). Follow up analyses indicated a statistical difference between PP and BW (Cohen’s d = 0.214, 95%CI [0.496, 1.834]; p < 0.001), and BW and CP (Cohen’s d = -0.104, 95%CI [-1.137, .008]; p = 0.036). Block jump height differed over the course of the season (F = 5.698; p = 0.008; ηp2 = 0.263). Follow up analyses indicated a difference between PP and CP (Cohen’s d = -0.611, 95%CI [-3.476, -0.089]; p = 0.038.). Attack jump height significantly improved over the course of the season (F = 4.426; p = 0.020; ηp2 = 0.217). Follow up analyses indicated a difference between PP and BW (Cohen’s d = -0.412, 95%CI [-6.684, -1.469]; p = 0.002). LPBI was improved throughout the season (F = 7.870; p = 0.002; ηp2 = 0.330). Follow up analyses indicated a difference between PP and CP (Cohen’s d = -0.774, 95%CI [-0.487, -0.044]; p = 0.016), and BW and CP (Cohen’s d = -0.533, 95%CI [-0.356, -0.010]; p = 0.025). No difference was noted in lean tissue mass. Conclusions: Athletes maintained or improved jump performance over the competitive season. The season impacted fat tissue percentage but not lean tissue mass. Practical Applications: Partitioners may desire to modify training programs aimed at lower body power and jump performance depending on the time of the competitive season. Practitioners may consider implementing approaches to offset fat tissue changes that appear to occur throughout the season. Acknowledgements: None