Should I Rest or Should I Go Now? A Randomized Cross-Over Trial Comparing Fixed and Self-Selected Rest Durations in High-Intensity Interval Training Cycling Sessions
Question
When total rest duration is matched, do fixed 90-second rests and self-selected rest distribution produce different performance, physiological, or psychological outcomes during HIIT cycling sessions?
Summary
This crossover study asked whether trained male cyclists perform or feel differently when HIIT rest is fixed versus self-selected, while total rest time is kept the same. Each cyclist completed nine 30-second cycling intervals and had 720 seconds total rest between intervals. In one condition, rest was fixed at 90 seconds between intervals; in the other, cyclists could distribute the same total rest however they wanted. Performance, heart rate, muscle activity, effort, fatigue, and enjoyment were highly similar. Self-selected rest increased perceived autonomy. For programming, this suggests that when total rest is fixed, trained cyclists can choose rest distribution without meaningfully changing the session's physical outcome.
Methodology
- Healthy amateur adult male cyclists riding at least 200 km/week.
- 24 participants.
- Cycling on SRM ergometer.
- Work intervals: 30 sec.
- Recovery: 720 sec total active recovery at 50 W, self-distributed between intervals.
- Intensity: Maximize accumulated watts across all intervals.
- 16.5 min work-plus-rest, excluding warmup/cooldown.
- Acute test session.
- Acute crossover.
- Randomized counterbalanced crossover trial.
- Watts, Heart rate, Muscle activity/fatigue proxy, and Rating of perceived effort were tracked.
Outcomes
Performance watts
Average watts and interval watt patterns were highly similar between fixed and self-selected rest conditions.
Average aggregated difference 0.57 watts, 95% CI -8.94 to 10.09.
Heart rate
Heart-rate responses were highly similar between conditions.
Average aggregated difference -0.85 bpm, 95% CI -2.89 to 1.18.
RPE
Perceived effort increased across intervals but did not differ meaningfully by condition.
Average aggregated difference 0.01 on 0-10 scale, 95% CI -0.29 to 0.30.
Perceived autonomy
Perceived autonomy was higher in the self-selected rest condition.
Differences across autonomy items roughly 0.5 to 1.5 mean estimate points.
Enjoyment and fatigue
Enjoyment and rating of fatigue were similar between conditions.
Insights
- For trained users, giving autonomy over rest distribution may improve perceived autonomy without changing acute work output when total rest is fixed.
- A rest-budget interface could let advanced users choose when to restart while preserving total workout structure.
- This evidence is about acute session design, not long-term adaptation.
Limitations
- All-male trained cyclist sample.
- Small sample.
- Acute crossover design without training adaptation outcomes.
- Cycling-specific ergometer protocol.
- Total rest was fixed, so it does not answer open-ended self-selected rest duration.
Safety
- No adverse events extracted from the paper.
- Findings are limited to healthy trained cyclists in a supervised laboratory session.