(32) THE EFFECTS OF A 13-WEEK HEAVY RESISTED SPRINT TRAINING PROGRAM ON FORCE-VELOCITY PROFILE SPRINT PERFORMANCE IN DIVISION II FEMALE VOLLEYBALL PLAYERS

Purpose: The purpose of this study was to compare the effects of a 13-week heavy (50% velocity decrement, V_DEC) versus very heavy (75% V_DEC) resisted sprint training (RST) program on sprint performance within Division II female volleyball players. Methods: Twenty-four Division II female volleyball players were recruited for this quasi-experimental design study. At baseline, the players completed three 30-meter (m) sprints, during which peak force (F₀), peak velocity (V₀), peak power (W), and slope were recorded. Athletes were categorized into two groups based on their slopes: force deficit (slope < 0.92, n = 16, 19.7 ± 0.48 y) or power group (slope > 0.92, n = 8, 18.4 ± 0.78 y). The players underwent a 13-week RST program (twice weekly) using the EXER-GENIE® (Thousand Oaks, CA) at prescribed loads set at 75% and 50% of peak V_DEC, defined as the force deficit and power groups, respectively. The players were tested in the 30-m sprint (2 sprints) at eight time points (Weeks 1, 2, 4, 6, 9, 11, 12, and 13) throughout the off-season. Three separate repeated measures analyses of variance 2 x 8 (group x time) were conducted to assess the within-group and between-group differences for F₀, V₀, and W. Results: No statistical differences existed between the groups for F₀, V₀, and W (Figure 1). Significant main effects were observed over time for the force deficit group with F₀ (p = 0.029), V₀ (p < 0.001), and W (p < 0.001). The average percentage changes for the force deficit group’s F₀, V₀, and W were 0.88 ± 0.04%, 0.37 ± 0.03%, and 1.25 ± 0.04%, respectively. For the power group, the average percentage changes for F₀, V₀, and W were 0.16 ± 0.03%, 0.13 ± 0.03%, and 0.31 ± 0.04%, respectively. Conclusions: The findings of this study indicate that RST at 75% and 50% V_DEC enhanced sprint performance, with no significant difference between the groups. Both groups experienced the largest percentage changes in F₀ and W from weeks 1 to 13, especially in the force deficit group compared to the power group. Athletes who initially lack force production in the sprint (slope < 0.92) may benefit from very heavy loading (75% V_DEC) more so than heavy loading (50% V_DEC) during RST. Practical Applications: The results give coaches and practitioners a better understanding of optimizing individual force-velocity profiles when loading athletes by V_DEC for RST. Individual force-velocity profiles should be considered when prescribing RST loads to increase the likelihood of enhancing sprint performance. Acknowledgements: None