Physiological, perceptual and affective responses to high-intensity interval training using two work-matched programs with different bout duration in obese males
Question
Do work-matched cycling HIIT programs using 10-second or 60-second bouts differ in physiological, perceptual, and affective responses during 8 weeks of training in obese males?
Summary
In 16 low-to-moderately active obese men, two work-matched 8-week cycling HIIT programs both improved peak power output, but the short-bout 10-second protocol produced lower lactate and RPE and more favorable affective responses than the 60-second protocol. Enjoyment stayed high in both groups and no injuries or adverse events were reported. The study is small and limited to supervised cycling in men with obesity.
Methodology
- Sixteen low-to-moderately active obese men completed two different supervised cycling HIIT protocols.
- 16 participants.
- Cycle ergometer.
- Work intervals: 48 x 10 s at 100% PPO.
- Recovery: 15 s at 15% PPO.
- Intensity: 100% PPO work; 15% PPO recovery.
- 20 min interval block plus 5 min warm-up and 3 min cool-down.
- 3 sessions/week.
- 8 weeks.
- Randomized two-arm supervised exercise training study comparing work-matched short-bout and long-bout cycling HIIT.
- Peak power output, Blood lactate, Perceived exertion, and Affective valence were tracked.
Outcomes
Peak power output
Both HIIT10 and HIIT60 improved peak power output after 12 and 24 sessions.
After 12 sessions: HIIT10 +13.2 +/- 2.8%, HIIT60 +12.9 +/- 3.4%; end training: +19.5 +/- 2.8% and +16.7 +/- 3.4%; p<0.001.
Blood lactate
HIIT10 produced lower lactate than HIIT60 and lactate fell over training only in HIIT10.
Between-group p=0.003 in first session and p=0.001 in final session; HIIT10 lactate reduced from 10 min onward by 28 +/- 19%, p<0.001.
RPE
HIIT10 had lower perceived exertion than HIIT60, and RPE decreased over training only in HIIT10.
Group effect p=0.027; HIIT10 RPE decreased by about 1.0 +/- 1.1 units in later training blocks.
Affective valence
Feeling Scale improved in HIIT10 but declined in HIIT60.
HIIT60 declined from 3.0 +/- 1.1 to 2.2 +/- 0.8 (p=0.026) and 2.1 +/- 0.9 (p<0.001).
Enjoyment
PACES enjoyment remained high and did not significantly differ by group or training block.
No significant group or training effects reported.
Safety
No musculoskeletal injuries or adverse events were reported.
Insights
- For users who find HIIT unpleasant, shortening bouts while matching work may reduce lactate, RPE, and negative affect.
- Post-session enjoyment and in-session affect can diverge, so both are useful product signals.
- Short-bout evidence here is cycling-specific; bodyweight translation should be conservative.
Limitations
- Very small sample.
- Men with obesity only.
- No non-exercise or moderate-intensity control group.
- Supervised cycling protocol with PPO-based workload.
- Short 8-week duration and no follow-up.
- Industry funding creates possible perceived conflict despite no reported study role.
Safety
- No musculoskeletal injuries were reported.
- No adverse events were reported.
- Participants were medically cleared by a cardiologist.