# Different whole body HIIT protocols do not promote different muscle thickness and functional adaptations among healthy physically active subjects

PMID: 39931129
Journal: Frontiers in sports and active living
Published: 2024
Authors: Evangelista AL, de Camargo JBB, Rica RL, Carnevali Júnior LC, Mallett GS, Bullo V, Bergamin M, Gobbo S, Bocalini DS

## Question

Do two different whole-body HIIT interval configurations produce different muscle-thickness and functional adaptations in healthy physically active adults?

## Summary

In 34 healthy physically active young adults, two whole-body bodyweight HIIT formats performed twice weekly for 6 weeks both improved vastus lateralis muscle thickness, muscular endurance, and estimated VO2max. A 30-seconds work/10-seconds rest format was not meaningfully better or worse than a 40-seconds work/20-seconds rest format.

## Population

- Healthy physically active Physical Education students and young adults
- Sample size: 34
- Sex: 22 men and 12 women; both groups had 11 men and 6 women
- Fitness level: Physically active; reported at least 150 min/week regular exercise
- Health status: No cardiometabolic conditions or medication use interfering with outcomes

## Methodology

- Randomized comparative exercise-training study
- 8-week experimental period with 6-week intervention
- Physical education/research setting in Brazil
- Randomized and controlled study design.

## Protocol

- WB-HIIT 30:10.
- Modality: Whole-body bodyweight exercises.
- Work intervals: 30 seconds.
- Recovery: 10 seconds passive recovery.
- Sets or repetitions: Nine exercises.
- Intensity: All-out effort.
- Frequency: 2 sessions/week.
- Program length: 6 weeks.
- WB-HIIT 40:20.
- Modality: Whole-body bodyweight exercises.
- Work intervals: 40 seconds.
- Recovery: 20 seconds passive recovery.
- Sets or repetitions: Nine exercises.
- Intensity: All-out effort.
- Frequency: 2 sessions/week.
- Program length: 6 weeks.

## Outcomes

### All outcomes
Status: improved
Both bodyweight HIIT configurations improved muscle thickness, muscular endurance, and VO2max.

Within-group improvements p<0.05.

### Group difference
Status: no clear change
No significant differences were found between 30:10 and 40:20 protocols.

Between-group differences not significant.

## Practical Insights

- For active users, 30:10 and 40:20 whole-body HIIT can be treated as interchangeable options.
- Bodyweight HIIT is highly translatable, but all-out intensity should be scaled for beginners.

## Limitations

- Small sample
- No inactive or no-exercise control group
- Active participants continued regular physical activity
- Adverse-event reporting absent despite reported 100% adherence

## Safety And Adherence

- Article did not report adverse events or injuries.
- All training protocols were supervised by researchers not involved in data analysis.
- Adherence was 100% in both groups; missed sessions were made up another day in the same week, and one G30x10 participant missed only the final Yo-Yo test.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/39931129/) (pubmed)
- [DOI](https://doi.org/10.3389/fspor.2024.1513030) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11808899/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.