Effects of a 24-week block-based versus circuit-based exercise program in overweight and obese Chilean adults
| ISRCTN | ISRCTN16284357 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN16284357 |
| Sponsor | Universidad Internacional Iberoamericana |
| Funder | Investigator initiated and funded |
- Submission date
- 05/07/2026
- Registration date
- 06/07/2026
- Last edited
- 06/07/2026
- Recruitment status
- Not yet recruiting
- Overall study status
- Ongoing
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
Overweight and obesity are very common health problems that increase the risk of developing conditions such as diabetes, high blood pressure, and heart disease. Physical exercise is one of the main strategies for improving the health of people with excess body weight. However, it is still unclear which way of organizing resistance training provides the greatest health benefits. This study aims to compare two types of resistance training (block training and circuit training) to evaluate their effects on heart function, body composition, physical activity levels, and quality of life in adults with overweight and obesity.
Who can participate?
Adult men with overweight or obesity who meet the study eligibility criteria and agree to participate voluntarily by providing written informed consent.
What does the study involve?
Participants will be randomly assigned to one of two resistance training programs: block training or circuit training. Both programs will last for 24 weeks and include three supervised exercise sessions per week. Before and after the training program, participants will undergo assessments of body composition, muscle strength, functional capacity, heart rate variability, physical activity level, and quality of life using physical measurements and validated questionnaires.
What are the possible benefits and risks of participating?
Participants may improve their physical fitness, body composition, cardiovascular health, physical activity level, and quality of life. The risks are similar to those of any exercise program and include muscle soreness, fatigue, or minor exercise-related injuries. All training sessions will be supervised by qualified professionals to minimize these risks.
Where is the study run from?
Arturo Prat University (Chile)
When is the study starting and how long is it expected to run for?
The study is expected to begin on 13 July 2026. Each participant will take part in the study for approximately 24 weeks, and the entire project is expected to last approximately 7 months.
Who is funding the study?
This study has no external funding.
Who is the main contact?
Héctor Fuentes Barría, hefuentes_@unap.cl
Contact information
Principal investigator, Scientific, Public
2120 Arturo Prat Avenue
Iquique
1110939
Chile
 ORCID ID |
0000-0003-0774-0848 |
|---|---|
| Phone | +56 (0)9996702455 |
| hefuentes_@unap.cl |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Blinded (masking used) |
| Control | Active |
| Assignment | Parallel |
| Purpose | Prevention, Treatment |
| Scientific title | Effects of a 24-week block-based versus circuit-based exercise program in overweight and obese Chilean adults |
| Study objectives | To evaluate the effects of a block based physical exercise program versus a circuit exercise program both individualized based on heart rate variability on cardiovascular autonomic regulation, body composition, and quality of life in overweight and obese Chilean adults. |
| Ethics approval(s) |
Approved 03/07/2026, Ethics Committee of the Iberoamerican International University (Calle 15 No. 36, between 10 and 12, Campeche, 24560, Mexico; +56 (0)(981) 811 0246; contacto@unini.edu.mx), ref: CR-252 |
| Health condition(s) or problem(s) studied | Cardiovascular autonomic regulation, body composition, and quality of life in Chilean adults with overweight and obesity |
| Intervention | The study involved a 24-week resistance training program with three weekly sessions (Monday, Wednesday, and Friday), each lasting 48 to 57 minutes. Participants were randomly assigned to either an experimental group (EG) or a control group (CG) using a stratified 1:1 allocation method to ensure unbiased group distribution. The EG performed resistance exercises in blocks (push-ups, mountain climbers, squats, jumping jacks, burpees, and skipping), while the CG performed the same exercises in a circuit format. Training intensity was monitored using Polar® devices, and total training volume was equivalent in both groups, with differences only in exercise distribution. The program was structured into a warm-up (5 min), main phase (38–47 min), and cool-down (5 min). Heart rate was targeted at 60–90% of maximum heart rate throughout the 24 weeks, with adjustments based on Karvonen’s formula. Both groups followed a fixed rest schedule between repetitions and sets. Assessments were conducted before and after the intervention to evaluate physical activity level, body composition, muscle strength, functional capacity, sprint performance, recovery, and quality of life. |
| Intervention type | Behavioural |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
|
| Completion date | 27/12/2026 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 44 Years |
| Sex | Male |
| Target sample size at registration | 52 |
| Total final enrolment | 52 |
| Key inclusion criteria | 1. Chilean adults aged 18 to 44 classified as overweight or obese based on body mass index 2. Participants must refrain from moderate- or vigorous-intensity physical activity for the 48 hours prior to each assessment or training session to avoid interfering with the acute physiological response 3. Punctual and regular attendance at all scheduled training sessions throughout the 24-week intervention 4. Sign an informed consent form 5. Proper understanding of the study's procedures, objectives, and potential risks |
| Key exclusion criteria | 1. Significant metabolic diseases or musculoskeletal conditions that limit physical exercise 2. Perform below 644 m on the 6-minute walk test 3. Simultaneously participating in another physical training program during the intervention period. |
| Date of first enrolment | 10/07/2026 |
| Date of final enrolment | 12/07/2026 |
Locations
Countries of recruitment
- Chile
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
06/07/2026: Study's existence confirmed by the Ethics Committee of the Iberoamerican International University.
