PMID 33801691

Research
All papers

Effects of Two Workload-Matched High-Intensity Interval Training Protocols on Regional Body Composition and Fat Oxidation in Obese Men

Tsirigkakis S, Mastorakos G, Koutedakis Y, Mougios V, Nevill AM, Pafili Z, Bogdanis GC

Question

Do workload-matched cycling HIIT protocols using 10-second versus 60-second bouts differ in effects on regional body composition and fat oxidation in obese adult men?

Summary

Sixteen inactive men with obesity completed 8 weeks of cycling HIIT using either very short 10-second bouts or longer 60-second bouts matched for total work. Both formats improved VO2peak, fat oxidation, trunk fat, waist circumference, and leg lean mass similarly, with high attendance and no reported injuries or adverse events.

Methodology

  • Inactive healthy adult men with obesity or high body fat.
  • 16 participants.
  • Cycle ergometer.
  • Work intervals: 10 seconds at 100% Wpeak.
  • Recovery: 15 seconds active recovery at 15% Wpeak.
  • Intensity: 100% Wpeak work; 15% Wpeak recovery.
  • 23 minutes including warm-up.
  • 3 sessions/week.
  • 8 weeks.
  • Parallel randomized training study comparing two workload-matched HIIT protocols
  • VO2peak, Body composition, Fat oxidation, and Blood lactate were tracked.

Outcomes

VO2peak

VO2peak improved similarly in both HIIT groups.

+20.0 +/- 7.2%, p<0.001, ES=1.42.

Improved

Body composition

Total and trunk fat mass decreased and leg lean mass increased similarly in both groups.

Total fat -1.81 kg, p=0.002; trunk fat -1.45 kg, p<0.001; leg lean mass +0.86 kg, p<0.001.

Improved

Fat oxidation

Fat oxidation increased over a wide range of submaximal intensities and peak fat oxidation increased.

PFO 0.20 +/- 0.05 to 0.33 +/- 0.08 g/min, p=0.001; Fatpeak 33.6 +/- 4.6 to 37.6 +/- 6.7% VO2peak, p=0.039.

Improved

Bout duration

The 10-second and 60-second protocols did not differ for the examined outcomes.

No significant group or interaction effects for main outcomes.

No clear change

Insights

  • When total work is matched, very short and longer cycling intervals can produce similar adaptations.
  • Cycling HIIT can be a lower-impact option for inactive men with obesity.
  • Readjusting intensity during a block helps maintain relative dose.

Limitations

  • No non-training control group
  • Small men-only sample
  • Diet was self-recorded rather than fully controlled

Safety

  • Attendance was high in both groups.
  • No physical injuries and no adverse events were reported.