Acute Effects of Work Rest Interval Duration of 3 HIIT Protocols on Cycling Power in Trained Young Adults
Question
How do 30-, 60-, and 90-second work-rest intervals affect acute cycling power, heart rate, lactate, and jump performance when total work is matched?
Summary
Twenty-two young trained men completed three acute all-out cycling HIIT protocols with 30-, 60-, or 90-second work intervals. Shorter intervals allowed higher power output while lactate and jump performance responses were not meaningfully different; all participants completed sessions without incidents.
Methodology
- Twenty-two active young men experienced with HIIT
- 22 participants.
- Cycle ergometer.
- Work intervals: 30 seconds.
- Recovery: 30 seconds passive rest.
- Intensity: All-out self-selected workload.
- 10-minute interval block after warm-up.
- One acute session.
- Crossover over three weeks.
- Counterbalanced crossover acute exercise study
- Cycling power, Heart rate, Blood lactate, and Countermovement jump were tracked.
Outcomes
Power
30-second intervals produced higher maximal and mean cycling power than longer intervals.
Pmax and Pmean p<0.001.
HR
Mean HR was higher in the 30-second protocol than the 90-second protocol.
HRmean p<0.001.
Lactate
Blood lactate did not differ significantly across interval durations.
p about 0.337-0.373.
CMJ
Jump height and jump power did not differ significantly by protocol.
CMJ height p=0.682; CMJ power p=0.832.
Insights
- For power-focused workouts, shorter all-out intervals may preserve output better than longer all-out intervals.
- A 1:1 work-rest density can be implemented with different interval lengths, but physiological and performance outputs differ.
- All-out interval prescriptions should be reserved for experienced users.
Limitations
- Small all-male sample.
- Participants were trained young adults, limiting beginner applicability.
- Acute-only protocol with no adaptation outcomes.
- No non-exercise control group.
Safety
- All 22 participants completed the three HIIT sessions without incidents.
- Participants were active, HIIT-experienced young men screened for medications and compliance with pre-session guidelines.
- Sessions were supervised by professional sport scientists with heart-rate and lactate monitoring.