(2) In-season Sprint Training Enhances Acceleration and Predicts Game Performance in Division 1 NCAA Baseball Athletes

Purpose: Sprint performance is crucial for competitive success in baseball, particularly acceleration during short-distance sprinting. Understanding how targeted sprint training during the competitive season (in-season training) impacts sprint capabilities and subsequent game outcomes can inform training interventions to optimize athletic performance. The purpose of this study is to examine the effects of an in-season sprint training program on sprint performance and its relationship to game outcomes (runs scored) in NCAA Division 1 baseball athletes across two competitive seasons (2022 and 2023). Methods: Thirty-nine baseball athletes (age: 20.9 ± 1.2 yrs; height: 1.87 ± 0.05 m) underwent weekly sprint testing (20-yard sprints) during the competitive seasons of 2022 and 2023. Athletes were classified each training cycle based on force-velocity profiles into "force-deficit" or "velocity-deficit" groups. The athlete distribution per training type varied notably across training cycles, with cycle 1 in 2022 having predominantly force-deficit athletes (36 force vs. 2 velocity) compared to a more balanced distribution in 2023 (cycle 1: 4 force vs. 4 velocity; cycle 2: 14 force vs. 28 velocity; cycle 3: 17 force vs. 20 velocity; cycle 4: 21 force vs. 23 velocity). Training interventions were tailored accordingly. Linear mixed-effects models assessed improvements in 20-yard sprint performance, adjusting for athlete height and training type. Predicted sprint performances were then linked to game outcomes (runs scored) using a linear regression. Significance was set at an alpha level of 0.05. Results: 20-yard sprint times (performance) significantly improved across training weeks, with substantial reductions by week 16 (-0.22 s, 95% CI [-0.25, -0.19], p< 0.001). A significant interaction indicated larger improvements during specific weeks in 2023 compared to 2022 (interaction β = -0.09 s at week 4, p< 0.001). Sprint segment-specific (10 yards and flying 10 yards) analysis demonstrated greater improvements in acceleration (first 10 yards, β = 0.42 s, 95% CI [0.41, 0.43], p< 0.001) compared to maximal velocity (flying 10 yards). Regression analysis showed improvements in predicted 10-yard sprint speed significantly predicted increased runs scored per game (β = 18.27 runs per m/s increase, 95% CI [9.16, 27.37], p< 0.001). Conclusions: In-season sprint training effectively enhanced acceleration and overall sprint performance among NCAA Division 1 baseball athletes. These performance enhancements directly correlated with improved game outcomes, specifically increased runs scored. Practical Applications: Coaches should consider integrating targeted sprint training based on individual sprint profiles, emphasizing acceleration-focused training, to improve both individual athlete performance and overall team game outcomes. Sprint training tailored to athletes' specific deficits can effectively enhance competitive success during the season. Acknowledgements: We acknowledge the support of this work by the Wu Tsai Human Performance Alliance at Stanford University and the Joe and Clara Tsai Foundation.