(32) RELATIONSHIPS BETWEEN LOWER EXTREMITY POWER AND BAT AND EXIT VELOCITIES IN COLLEGIATE SOFTBALL PLAYERS

Purpose: To examine the relationship between lower extremity power and bat and exit velocities.

Methods: Nineteen Division I collegiate softball (CSB) players (age = 20.2 ± 1.6 yr; Ht = 167.7 ± 5.9 cm; BM = 69.4 ± 7.5 kg; LBM = 51.2 ± 4.7 kg; %BF = 26.0 ± 5.0%) volunteered for this study. Bilateral countermovement jump (BCMJ), unilateral countermovement jump (UCMJ), lateral to medial jump (LMJ), and standing long jump (SLJ) were recorded from force plates. Peak power, relative peak power, and maximum jump height or distance were recorded. Athletes hit 5 softballs from a batting tee while swinging from force plates. Mean bat velocity (MBV) and best bat velocity (BBV) were recorded using a Blast bat sensor while mean exit velocity (MEV) and best exit velocity (BEV) were recorded using a Stalker radar gun. Peak forces were recorded for the drive (back) and stride (front) foot in the vertical, anterior-posterior, and medio-lateral (Stride-Fx; Stride-Fx) directions while hitting. Simple regression and correlational analyses were conducted. Statistical significance was set at an alpha level of p ≤ 0.05.

Results: BCMJ height (BCMJ-Ht) and BBV were moderately correlated (r = 0.458). Regression analysis indicated 21.0% of the variance in BBV is accounted for by the change in BCMJ-Ht. Stride-Fx and BBV were moderately correlated (r = 0.569). Regression analysis indicated 32.4% of the variance in BBV is accounted for by the change in Stride-Fx. BCMJ peak power (BCMJ-PP) and MEV were moderately correlated (r = 0.502). Regression analysis indicated 25.2% of the variance in MEV is accounted for by the change in BCMJ-PP. BCMJ-Ht and MEV were moderately correlated (r = 0.474). Regression analysis indicated 22.5% of the variance in MEV is accounted for by the change in BCMJ-Ht. BCMJ-PP normalized for lean body mass (BCMJ-PP/ LBM) and MEV were moderately high correlated (r = 0.648). Regression analysis indicated 42.0% of the variance in MEV is accounted for by the change in BCMJ-PP/ LBM. BCMJ-PP and BEV were moderately correlated (r = 0.484). Regression analysis indicated 23.4% of the variance in BEV is accounted for by the change in BCMJ-PP. BCMJ-PP/ LBM and BEV were moderately correlated (r = 0.495). Regression analysis indicated 24.5% of the variance in BEV is accounted for by the change in BCMJ-PP/ LBM. There were no significant relationships between UCMJ, LMJ, or SLJ with the bat velocity (BV) and exit velocity (EV) metrics.

Conclusions: Significant relationships between lower body power and BV and EV in CSB players exist. Stride foot forces have a relationship to hitting performance in CSB athletes. BCMJ-Ht was significantly related to and predicted BBV and MEV. BCMJ-PP and BCMJ-PP/LBM were significantly related to and predicted MEV and BEV. While hitting, the lateral force of the stride foot was significantly related to and predicted BBV. PRACTICAL APPLICATIONS: Higher power output during jump testing can be a useful, predictive, and evaluative tool to identify athletes who have the potential to hit with either greater BV or EV. Strength coaches should improve lower body power of CSB players to improve hitting velocities. College coaches should recruit powerful SB players since there was a relationship between lower body power relative to LBM and greater BV and EV. If applicable, a coach should look at stride foot force production when a player hits as it may identify a greater ability to transfer force from the ground into the bat and ball.

Acknowledgements: We would like to thank the Louisiana Tech softball hitters for participating in this study and Chris Watson, Elise Bordlee, Austin Reedy, Sam Briehn, and Charles Arnold for helping to collect data.