Comparing three ways of organising rest during weighted jump squats in resistance-trained men
| ISRCTN | ISRCTN91525461 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN91525461 |
| Sponsor | Fuzhou University |
| Funder | Investigator initiated and funded |
- Submission date
- 29/06/2026
- Registration date
- 06/07/2026
- Last edited
- 14/07/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Other
Plain English summary of protocol
Background and study aims
Weighted jump squats are commonly used by athletes and coaches to improve jumping and explosive performance. However, completing many repetitions without enough rest may cause temporary fatigue and reduce the expected performance benefits. This study aimed to compare three different ways of organising repetitions and rest periods during weighted jump squats in resistance-trained men.
Who can participate?
Healthy resistance-trained men aged 18-24 years who had at least 2 years of resistance-training experience, regularly trained their lower body, and could perform a back squat with a load of at least 1.5 times their body mass.
What does the study involve?
Participants first attended a familiarisation session. They then completed three experimental sessions in a randomly assigned order, with 72 hours between sessions.
During each session, participants performed 30 weighted jump squats using a load equal to 30% of their back-squat one-repetition maximum. The repetitions and rest periods were organised in one of three ways:
1. Three sets of 10 repetitions with 120 seconds of rest between sets.
2. Six sets of five repetitions with 48 seconds of rest between sets.
3. Three sets of five repetitions, followed by 40 seconds of rest and another five repetitions, with 60 seconds of rest between sets.
Jump performance, blood lactate concentration, and perceived exertion were assessed before and/or during the 12 minutes after each exercise session.
What are the possible benefits and risks of participating?
Participants were not guaranteed to receive a direct personal benefit. The findings may help coaches and athletes organise rest periods during weighted jump-squat exercise more effectively.
Possible risks included temporary muscle fatigue, muscle soreness, discomfort from the earlobe blood sample, and a small risk of muscle or joint strain during exercise. All exercise and testing procedures were supervised by trained researchers.
Where is the study run from?
Fuzhou University (China)
When did the study start and how long did it run for?
January 2026 to March 2026
Who is funding the study?
Investigator initiated and funded
Who is the main contact?
Dr Jiehong Wu, sky946@fzu.edu.cn
Contact information
Public, Scientific, Principal investigator
Department of Physical Education, Fuzhou University, No. 2 Wulongjiang North Avenue
Fuzhou
350108
China
| Phone | +86 (0)18810937441 |
|---|---|
| sky946@fzu.edu.cn |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Open (masking not used) |
| Control | Active |
| Assignment | Crossover |
| Purpose | Exercise performance enhancement and investigation of acute physiological and perceptual responses to different weighted jump-squat set configurations |
| Scientific title | Effects of weighted jump-squat set configuration on acute explosive performance and fatigue responses in resistance-trained men: a randomized crossover study |
| Study objectives | The primary objective was to compare the acute effects of traditional-set, cluster-set, and rest-redistribution weighted jump-squat configurations on vertical jump height in resistance-trained men. The secondary objectives were to compare the magnitude and time course of relative peak power output, reactive strength index-modified, blood lactate concentration, and rating of perceived exertion during the 12-minute postexercise recovery period. It was hypothesized that the cluster-set and rest-redistribution configurations would produce smaller immediate reductions and greater subsequent improvements in countermovement-jump performance than the traditional-set configuration, and that the cluster-set configuration would produce the lowest blood lactate concentration and perceived exertion. |
| Ethics approval(s) |
Approved 05/01/2026, Fuzhou University Review Board for Human Participants (Fuzhou University, No. 2 Wulongjiang North Avenue, Fuzhou, 350108, China; +86 (0)13763898963; 7005477@qq.com), ref: 2026001 |
| Health condition(s) or problem(s) studied | Acute explosive performance and fatigue-related responses to weighted jump-squat exercise in healthy resistance-trained men |
| Intervention | This was a randomized, counterbalanced, three-condition crossover study. Participants first completed one familiarization session and subsequently completed three experimental trials separated by 72 hours. All trials were conducted at approximately the same time of day (±1 hour). The order of the three experimental conditions was determined using a computer-generated counterbalanced sequence. The sequence was generated by a researcher who was not involved in data collection, and the allocated condition was concealed from participants until the beginning of each experimental visit. At each experimental visit, baseline blood lactate concentration was measured before participants completed a standardized 10-minute warm-up consisting of 5 minutes of cycling followed by 5 minutes of dynamic and plyometric exercises. After 5 minutes of seated rest, baseline countermovement-jump testing was performed. Participants then completed one of three weighted jump-squat protocols on a Smith machine, with the bar positioned across the upper back. The external load was equivalent to 30% of the participant’s back-squat one-repetition maximum. 1. Traditional-set condition: 3 sets of 10 repetitions, with 120 seconds of inter-set rest. 2. Cluster-set condition: 6 sets of 5 repetitions, with 48 seconds of inter-set rest. 3. Rest-redistribution condition: 3 sets of 5 + 5 repetitions, with 40 seconds of intra-set rest and 60 seconds of inter-set rest. All conditions included 30 repetitions at 30% of back-squat one-repetition maximum and 240 seconds of total programmed rest. Blood lactate concentration and rating of perceived exertion were assessed immediately after exercise and at 4, 8, and 12 minutes after each protocol. At each assessment time point, blood lactate concentration and rating of perceived exertion were obtained before countermovement-jump testing. Participants then performed three countermovement jumps separated by 30 seconds, and the mean of the three trials was used for analysis. |
| Intervention type | Behavioural |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
Updated 14/07/2026, previous version: |
| Completion date | 04/03/2026 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 25 Years |
| Sex | Male |
| Target sample size at registration | 24 |
| Total final enrolment | 24 |
| Key inclusion criteria | 1. Healthy male participants within the specified age range 2. At least 2 years of resistance-training experience 3. Participation in resistance training at least twice per week 4. Regular lower-limb resistance training during the previous 6 months 5. A back-squat one-repetition maximum of at least 1.5 times body mass 6. Willingness to provide written informed consent and complete the study procedures |
| Key exclusion criteria | 1. Lower-limb injury or pain during the previous 6 months 2. Neurological, cardiovascular, or metabolic disorders 3. Recent interruption of regular resistance training 4. Current use of supplements or medications that could affect exercise performance or fatigue-related responses |
| Date of first enrolment | 15/01/2026 |
| Date of final enrolment | 16/01/2026 |
Locations
Countries of recruitment
- China
Study participating centre
Fuzhou
China
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
14/07/2026: The secondary outcomes were updated.
13/07/2026: Masking was used from blinded (masking used) to open (masking not used).
29/06/2026: Study's existence confirmed by the Fuzhou University Review Board for Human Participants.
