Accentuated Eccentric Loading in Countermovement Jumps Vs. Drop Jumps: Effects on Jump Performance and Strength in A Randomized Controlled Trial.

Abstract

This study examined the effects of Accentuated Eccentric Loading Countermovement Jump (AEL CMJ) training on jump performance, lower body strength, sprint performance, and change of direction ability, compared to drop jump (DJ) training. This study used a randomized controlled trial (RCT) with a parallel design. Forty men physical education students (Mean ± SD: age 22.60 ± 3.24 years, body mass 75.21 ± 8.12 kg, height 1.79 ± 0.07 m) were randomly assigned to AEL (n = 14), DJ (n = 13), or a control group (CON, n = 13). The AEL and DJ groups trained three times per week for 8 weeks, while the CON group maintained their usual routines. All groups with similar levels of physical activity outside the training. Pre-, mid- (4 weeks), and post-intervention (8 weeks) assessments measured jump performance (CMJ and squat jump (SJ)), 1RM squat strength, 30 m sprint time, and change of direction (T-test). A mixed-effects model evaluated group and time effects. Significant group × time interactions were observed for CMJ height (P = 0.006), with both AEL and DJ training improving CMJ (AEL: +11.8%, ES = 0.77; DJ: +7.7%, ES = 0.47), SJ height (AEL: +5.7%, ES = 0.37; DJ: +11.3%, ES = 0.66), and 1RM squat (AEL: +7.0%, ES = 0.44; DJ: +8.4%, ES = 0.46) at 8 weeks. Neither training method significantly improved sprint or change of direction performance. Additionally, no significant gains were seen in any indicator at 4 weeks. These results indicate that AEL CMJ and DJ training both effectively enhance vertical jump and strength, positioning AEL CMJ as an effective alternative or complement to DJ training.