The Relationship Between Vertical Jump Acceleration And Fastball Velocity In Major League Baseball

Vertical jump has been widely used to estimate athletic potential in diverse sport contexts. Moderate associations between vertical jump and fastball velocity (FV) have been found in various levels of play. Vertical jump acceleration and FV in Major League Baseball (MLB) remains unexamined. PURPOSE: To evaluate the relationship between vertical jump acceleration and FV in MLB pitchers. METHODS: We tested 28 MLB pitchers using a Proteus device (Proteus Motion, USA). All athletes wore a waist harness, faced away from the equipment, and performed 5 repetitions of vertical jump against 6 lb of resistance. Peak acceleration in m/s2 was recorded for each repetition, and the mean of all 5 peak values was used as the independent variable. The dependent variable was peak in-game FV recorded subsequently by the MLB. Simple linear regression examined this relationship. Further regression models held significant confounders constant. RESULTS: Players were 29.5 ± 4.1 years of age and had played 4.1 ± 3.1 previous MLB seasons. Height was 75.6 ± 2.4 inches, weight was 213.1 ± 20.3 lb, and vertical jump acceleration was 13.0 ± 2.6 m/s2. Peak FV was 92.6 ± 2.6 mph; it was related to age (r2 = 0.231; β = -0.303; p = 0.010; 95% CI: -0.526, -0.080) and number of seasons played (r2 = 0.306; β = -0.456; p = 0.002; 95% CI: -0.733, -0.179) but not height (p = 0.784) or weight (p = 0.617). In a simple linear regression, vertical jump acceleration significantly predicted FV (r2 = 0.449; β = 0.666; p < 0.001; 95% CI: 0.368, 0.963). Holding age (p = 0.005) constant, vertical jump acceleration retained significance (β = 0.611; p < 0.001; 95% CI: 0.350, 0.872); the overall model was significant (r2 = 0.602; p < 0.001). Holding number of seasons played (p = 0.006) constant, vertical jump acceleration retained significance (β = 0.555; p < 0.001; 95% CI: 0.284, 0.827); the overall model was significant (r2 = 0.594; p < 0.001). Age (p = 0.481) and seasons played (p = 0.149) did not predict vertical jump acceleration. CONCLUSION: Advancing age and number of seasons played corresponded to reductions in FV, whereas increased vertical jump acceleration predicted higher velocity. This finding was not affected when controlling for age or seasons played. Exercise prescriptions that increase vertical jump acceleration should be considered for professional pitchers aiming to increase FV.