The effects of single and combined jump exercises utilizing fast and slow stretch-shortening cycle on physical fitness measures in healthy adult males: A randomized controlled trial.

This study aimed to compare the effects of six-week volume-equated jump training using drop jump (DJ), countermovement jump (CMJ), or a combination of both (COMB) on the physical fitness of adult males. Participants were randomly assigned to DJ (n=10), CMJ (n=9), or COMB (n=10) training groups or an active control group (n=7). Performance data were collected for 10-m and 30-m sprint, DJ, CMJ, standing long jump (SLJ), triple-hop jump, change of direction speed (CODS), and maximal isometric strength. The DJ demonstrated improvements in the 10-m sprint, CMJ, and SLJ (g=0.62–1.13, %Δ=3.0–10.8). The CMJ group improved in the 10-m and 30-m sprints, CODS, CMJ and SLJ (g=0.34–1.17, %Δ=3.4–10.5). The COMB group displayed progress in CMJ and SLJ (g=0.46–0.61, %Δ=6.4–8.6). In comparison to the control and COMB groups, the DJ and CMJ groups improved the 10-m sprint (p=0.008, ηp2=0.311), and in comparison to the control group, the CMJ group improved SLJ (p=0.037, ηp2=0.220). To conclude, the findings presented here deviate from the training principle of specificity, particularly in relation to ground contact time. This suggests that the classification of jump exercises into fast- and slow-SSC categories based solely on ground contact time might oversimplify a more intricate phenomenon.