Effects of two drop-jump protocols with different volumes on vertical jump performance and its association with the force-velocity profile.

Abstract

This study aimed to evaluate the changes in countermovement jump (CMJ) height after two drop-jump (DJ) protocols with different volumes, and to explore the possibility of predicting the changes in CMJ height based on the vertical force-velocity (F-v) profile. Thirty-four male athletes (age: 21.9 ± 2.0years) were tested on three occasions. The F-v profile during the CMJ exercise was determined in the first session. Two DJ protocols (low-volume [1 set of 5 DJ trials from a 30cm height] and high-volume [3 sets of 5 DJ trials from a 30cm height]) were randomly performed during the second and third sessions, and the unloaded CMJ height was evaluated before (Pre), 4min (Post4), 8min (Post8), and 12min (Post12) after the DJ protocol. CMJ height was significantly higher at Post4 (2.5cm [95% confidence interval (CI) = 2.0-3.0cm]; ES = 0.35), Post8 (2.1cm [95% CI = 1.4-2.8cm]; ES = 0.29) and Post12 (2.2cm [95% CI = 1.4-3.0cm]; ES = 0.30) compared to Pre. The only significant interaction (protocol × time) was caused by a higher increment in CMJ height at Post4 for the low-volume (8.1 ± 3.7%) compared to the high-volume (5.8 ± 3.9%) protocol. The F-v profile did not explain a significant part of the change in CMJ height (variance explained < 10%). These results suggest that low-volume DJ protocols could be more efficient to acutely increase CMJ performance, while the change in CMJ height was not affected by the F-v profile.