PMID 41210262

Research
All papers

Optimising adolescent health: a comparative study of high-intensity interval training and moderate-intensity continuous training on body composition and cardiovascular fitness in sedentary male youth

Yahat H

Question

How do 8 weeks of school-based HIIT and MICT compare for body composition and cardiovascular fitness in sedentary normal-weight male adolescents?

Summary

In sedentary male adolescents, 8 weeks of supervised running HIIT and MICT both reduced body fat, body weight, skinfold thickness, and resting heart rate compared with a no-exercise control group. HIIT achieved similar improvements with a shorter 20-minute session than the 30-minute MICT session. However, the article reports incomplete heart-rate fidelity data and a failed intensity manipulation check, so claims about the intended intensity contrast need caution.

Methodology

  • Sedentary male adolescents aged 16-17.
  • 60 participants.
  • Running/walking.
  • Work intervals: 30 s at 80-90% HRmax.
  • Recovery: 90 s walking at about 50% HRmax.
  • Intensity: HRR-prescribed high-intensity running.
  • 20 min including warm-up and cool-down.
  • 4 sessions/week.
  • 8 weeks.
  • Three-arm randomized controlled trial.
  • Body fat percentage, Body weight, Skinfold thickness, and Resting heart rate were tracked.

Outcomes

Body fat percentage

Body fat fell in HIIT and MICT more than control.

HIIT 26.00% to 20.00%; MICT 25.80% to 20.10%; control 25.20% to 24.20%; F(2,57)=185.97, p<0.001, eta2=0.86.

Improved

Body weight

Body weight declined by about 5.75 kg in both active arms and minimally in control.

HIIT 77.15 to 71.40 kg; MICT 77.20 to 71.45 kg; control 79.10 to 78.40 kg; F(2,57)=157.06, p<0.001, eta2=0.84.

Improved

Skinfold thickness

Skinfold measures decreased in both active arms more than control.

HIIT 24.90 to 18.75 mm; MICT 24.30 to 18.55 mm; control 23.05 to 22.10 mm; eta2=0.961.

Improved

Resting heart rate

Resting heart rate decreased in HIIT and MICT, with no meaningful control improvement.

HIIT 78.25 to 71.10 bpm; MICT 80.05 to 74.35 bpm; control 78.45 to 78.65 bpm; eta2=0.953.

Improved

Intensity fidelity

Heart-rate manipulation check did not confirm clear separation between prescribed intensities.

Paired tests: HIIT p=0.693; MICT p=0.275.

Unclear

Insights

  • A 6 x 30 s running HIIT session can fit school schedules and may match longer MICT for short-term body-composition outcomes.
  • Verify actual intensity with time-in-zone or RPE when making intensity-specific claims.
  • Results apply best to supervised adolescent male settings.

Limitations

  • Male-only adolescent sample.
  • Short duration and no follow-up.
  • Indirect fitness measure using resting heart rate rather than VO2max.
  • Dietary intake not quantified.
  • Control physical activity not objectively monitored.
  • Incomplete fidelity/adherence capture.

Safety

  • No adverse events were observed or reported.
  • No injuries requiring first aid or medical evaluation.
  • No syncope, chest pain, respiratory distress, heat illness, harm-related session terminations, or harm-related withdrawals.