PMID 34658918

Research
All papers

Functional High-Intensity Interval Training Lowers Body Mass and Improves Coordination, Strength, Muscular Endurance, and Aerobic Endurance of Inmates in a German Prison

Dransmann M, Koddebusch M, Gröben B, Wicker P

Question

Can a short functional HIIT program improve body composition and fitness in male prison inmates?

Summary

A 6-week supervised functional HIIT program in a German prison was associated with lower body mass and better coordination, strength, muscular endurance, and aerobic endurance among the 11 men included in final analysis. Because there was no control group, a small final sample, and a highly specific prison context, the findings are best treated as feasibility evidence.

Methodology

  • Male inmates in an open German prison; final analysis n=11.
  • 11 participants.
  • Bodyweight exercise and running.
  • Work intervals: Varied; examples include 20-60 s work and 4-min running intervals.
  • Recovery: Varied by session.
  • Intensity: All-out target; average 77.95 +/- 5.58% HRmax.
  • About 40 min including warm-up.
  • 3 sessions/week.
  • 6 weeks.
  • Single-arm pre-post intervention
  • Body composition, Motor performance, and Aerobic endurance were tracked.

Outcomes

Body mass

Body mass and BMI decreased after 6 weeks.

Body mass p=0.007; BMI p=0.006.

Improved

Coordination

Lateral jumps improved from 41.82 to 48.00.

p=0.024.

Improved

Muscular endurance

Push-ups and sit-ups improved.

Both p<0.001.

Improved

Aerobic endurance

VIFT and estimated VO2max improved.

Both p<0.001.

Improved

Sprint

20-m sprint time did not change.

p=0.736.

No clear change

Insights

  • Varied bodyweight HIIT can be delivered with minimal equipment in constrained settings.
  • Group supervision and participant-selected music may help adherence.
  • Because there was no control group, this should not be used as strong efficacy proof.

Limitations

  • No control group
  • Small final sample
  • Special prison population
  • Diet not tracked
  • Possible drug-use confounding
  • Field-test learning effects

Safety

  • Two participants dropped out for medical reasons, but the article did not provide detailed adverse-event attribution.
  • No physician clearance was performed.