(50) DROP JUMP PERFORMANCE IS BETTER ASSOCIATED WITH THE LATER STAGES OF SPRINT ACCELERATION IN MALE COLLEGIATE ATHLETES

The drop jump (DJ) is a commonly used plyometric test that uses the stretch-shortening cycle to measure lower-body explosiveness. Past research has found strong correlation between DJ jump height and sprint speed, but it is yet to be determined what stage of a sprint acceleration is strongly correlated with DJ height.

Purpose: To assess the strength of association of drop jump performance with the various stages of sprint acceleration.

Methods: This study utilized 61 male Division I collegiate athletes from the basketball (10), football (31) and track (10) teams. Each athlete performed three trials of drop jumps and 30-meter sprints with the best trial of each being used for analysis. Drop jump data were collected by athletes dropping from a 45.72 cm high box and landing on two force platforms sampling at 1000 Hz, with their hands on their hips for the entire motion. Data were collected from their 30-meter sprints, including the split times at every 5 meters. Statistical analysis consisted of Pearson r correlations to examine relations amongst jump height and reactive strength index (RSI) from the drop jump with sprint completion times at 5-, 10-, 15-, 20-, 25-, and 30-meters. Significance was set at an alpha level of p< 0.05.

Results: Mean ± standard deviation (SD) jump height was 0.35 ± 0.07cm, and sprint split times for the 5-, 10-, 15-, 20-, 25-, and 30-meters were 0.99 ± 0.06s, 1.74 ± 0.07s, 2.38 ± 0.10s, 2.99 ± 0.14s, 3.58 ± 0.18s, and 4.17 ± 0.24s, respectively. No correlations were found between the 5-, 10-, and 15-meter split times and DJ jump height. Significant correlations between DJ height and sprint times were found for the 20-meter time (r = -0.280, p = 0.047). For the 25-meter split time, the correlation was not significant, although it approached significance (r = -0.273, p = 0.052). Additionally, significant correlation was found for the 30-meter sprint times and DJ height (r = -0.303, p = 0.030). RSI values followed a similar pattern with significant correlations with the sprint completion times at 20 meters (r = -0.325, p = 0.020), 25 meters (r = -0.305, p = 0.029) and 30 meters (r = -0.397, p = 0.004).

Conclusion: The analyses showed a significant association between the later stages of a sprint acceleration and DJ height and RSI variables. For our sample, the early phases of sprint acceleration did not demonstrate a strong association with DJ height and RSI. PRACTICAL APPLICATIONS: Coaches and athletes should be aware that DJ performance metrics are associated with later stage sprint completion times. Accordingly, plyometric training should be considered for inclusion in sprint development programs.

Acknowledgements: None