LAUSR

Purpose 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. Method Thirty-four male athletes (age: 21.9 ± 2.0 years) 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 30 cm height] and high-volume [3 sets of 5 DJ trials from a 30 cm height]) were randomly performed during the second and third sessions, and the unloaded CMJ height was evaluated before (Pre), 4 min (Post4), 8 min (Post8), and 12 min (Post12) after the DJ protocol. Results CMJ height was significantly higher at Post4 (2.5 cm [95% confidence interval (CI) = 2.0–3.0 cm]; ES = 0.35), Post8 (2.1 cm [95% CI = 1.4–2.8 cm]; ES = 0.29) and Post12 (2.2 cm [95% CI = 1.4–3.0 cm]; 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%). Conclusions 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.