Research article - (2025)24, 20 - 30
DOI: https://doi.org/10.52082/jssm.2025.20
Accentuated Eccentric Loading in Countermovement Jumps Vs. Drop Jumps: Effects on Jump Performance and Strength in A Randomized Controlled Trial
Zhengqiu Gu1, Chong Gao1, Hang Zheng1, Kaifang Liao2, Chris Bishop3, Jonathan Hughes4, Mingyue Yin1, Zhiyuan Bi1, Zhan Li1, Jian Li1, Meixia Chen5, Jianxi Wei6, Yongming Li1,7,
1School of Athletic Performance, Shanghai University of Sport, Shanghai, China
2School of Physical Education, Chengdu Sport University, Sichuan, China
3Faculty of Science and Technology, London Sports Institute, Middlesex University, London, UK
4Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
5Shanghai Minhang Experimental High School, Shanghai, China
6The Research Center of Military Exercise Science, The Army Engineering University of PLA, Nanjing, China
7China Institute of Sport Science, Beijing, China

Yongming Li
✉ School of Athletic Performance, Shanghai University of Sport, Shanghai 200438, China
Email: liyongming@sus.edu.cn
Received: 15-11-2024 -- Accepted: 11-12-2024
Published (online): 01-03-2025
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.
Key words: Plyometric, stretch-shortening cycle, power, reactive strength, T-test, squat

Key Points
  • Eight-week AEL CMJ training and DJ training improved vertical jump performance and lower body strength, both training methods with similar effects.
  • Neither 8-week AEL CMJ training and DJ training improved acceleration or COD performance.
  • Neither 4-week AEL CMJ training and DJ training improved vertical jump performance, lower body strength, acceleration or COD performance.








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Accentuated Eccentric Loading in Countermovement Jumps Vs. Drop Jumps: Effects on Jump Performance and Strength in A Randomized Controlled Trial
Zhengqiu Gu, Chong Gao, Hang Zheng, Kaifang Liao, Chris Bishop, Jonathan Hughes, Mingyue Yin, Zhiyuan Bi, Zhan Li, Jian Li, Meixia Chen, Jianxi Wei, Yongming Li
2025(24), 20 - 30.
DOI: https://doi.org/10.52082/jssm.2025.20