# Enhancing adolescent health: the role of strength and endurance school-based HIIT interventions in physical fitness and cognitive development

PMID: 40420991
Journal: Frontiers in psychology
Published: 2025
Authors: Pérez-Ramírez JA, Santos MP, Mota J, González-Fernández FT, Villa-González E

## Question

Do 8 weeks of strength- and endurance-focused HIIT integrated into PE classes improve physical fitness and cognitive attention outcomes in adolescents?

## Summary

This quasi-experimental school study tested 8 weeks of PE-class HIIT in Spanish adolescents. The experimental group completed one strength-focused and one endurance-focused HIIT session per week, using 30-second work and 30-second rest blocks with heart-rate monitoring. Fitness and attention measures improved, but weight and waist circumference increased, and the study was not randomized.

## Population

- Healthy secondary education students aged 13-17 years in a Spanish school.
- Sample size: 84
- Age: Experimental 15.03 +/- 0.18 years; control 15.19 +/- 0.74 years.
- Fitness level: General school adolescents familiarized with PE protocols and RPE.
- Health status: Excluded major medical conditions, injuries, relevant medications, and non-attendance above 20%.

## Methodology

- Quasi-experimental pre-post study with experimental and control groups assigned by class.
- 8 weeks during the school year.
- Secondary-school physical education classes in Spain.
- Controlled study design.

## Protocol

- School strength and endurance HIIT.
- Modality: Mixed bodyweight, functional, martial-arts-inspired, strength, and endurance drills.
- Work intervals: 30 seconds high intensity.
- Recovery: 30 seconds rest.
- Sets or repetitions: 7-8 exercises repeated four times each.
- Intensity: High intensity with mean HR 169.53 +/- 2.93 bpm; HRmax estimated as 220 - age.
- Session duration: 35-40 minutes of engagement motor time within a 55-minute PE class.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.
- Progression: Progression in intensity, variety, and grouping was planned but not fully specified.
- Standard physical education.
- Modality: Cooperation-opposition games and sports.
- Intensity: Lower mean HR than experimental group: 144.54 +/- 30.08 bpm.
- Session duration: 55-minute PE class.
- Frequency: Regular PE schedule.
- Program length: 8 weeks.

## Outcomes

### Physical fitness
Status: improved
Experimental group improved horizontal jump, handgrip, 4 x 10 m time, and estimated VO2max; control did not improve most fitness outcomes.

EG HJ +4.68% p=0.001; handgrip +3.24% p=0.03; 4x10 m -8.35% p=0.001; VO2max +5.06% p=0.001.

### Attention
Status: improved
Experimental group improved concentration and reduced omission and commission errors.

Concentration +27.44% p=0.001; omissions -53.35% p=0.001; commissions -87.67% p=0.001.

### Anthropometry
Status: worse/safety concern
Experimental group weight and waist circumference increased; BMI increase was not significant.

Weight +2.82% p=0.001; WC +7.99% p=0.001; BMI +6.80% p=0.23.

### Heart rate intensity
Status: improved
Experimental sessions produced higher HR than control PE.

EG 169.53 +/- 2.93 bpm vs CG 144.54 +/- 30.08 bpm, p<0.001.

## Practical Insights

- School HIIT can be organized as separate strength and endurance sessions within existing PE.
- Heart-rate monitoring is useful for managing adolescent school HIIT intensity.
- Fitness and attention gains should be separated from body-composition claims.

## Limitations

- Quasi-experimental class assignment.
- School context and student motivation, nutrition, sleep, and extracurricular activity were uncontrolled.
- Intervention length limited by school calendar.
- No long-term follow-up.
- VO2max was estimated rather than directly measured.

## Safety And Adherence

- No adverse events were reported.
- Students with relevant medical conditions, injuries, or medications were excluded.
- HR monitoring was used so students could moderate intensity.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/40420991/) (pubmed)
- [DOI](https://doi.org/10.3389/fpsyg.2025.1568129) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12104269/) (full text)

## Agent Guidance

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