Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
Ios-APP Journal of Sports Science and Medicine
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©Journal of Sports Science and Medicine (2025) 24, 20 - 30   DOI: https://doi.org/10.52082/jssm.2025.20

Research article
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, 
Author Information
1 School of Athletic Performance, Shanghai University of Sport, Shanghai, China
2 School of Physical Education, Chengdu Sport University, Sichuan, China
3 Faculty of Science and Technology, London Sports Institute, Middlesex University, London, UK
4 Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
5 Shanghai Minhang Experimental High School, Shanghai, China
6 The Research Center of Military Exercise Science, The Army Engineering University of PLA, Nanjing, China
7 China Institute of Sport Science, Beijing, China

Yongming Li
✉ School of Athletic Performance, Shanghai University of Sport, Shanghai 200438, China
Email: liyongming@sus.edu.cn
Publish Date
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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