Response to Three Weeks of Sprint Interval Training Cannot Be Explained by the Exertional Level
Question
Can different responses to 3 weeks of sprint interval training be explained by exertional level during training?
Summary
In healthy untrained men, 3 weeks of supervised all-out sprint interval cycling improved VO2peak overall and average sprint power, but people differed in power response. The difference between high and low responders was not explained by heart-rate intensity, lactate response, or acute muscle fatigue measures.
Methodology
- Healthy untrained men
- 26 participants.
- Cycle ergometer.
- Work intervals: 30 s all-out sprint.
- Recovery: 4 min very low resistance pedaling.
- Intensity: All-out against 7.5% body mass resistance.
- Varied by bout count.
- 3 sessions/week.
- 3 weeks.
- Single-arm supervised sprint interval training study with responder subgroup analysis
- Average sprint power, VO2peak, and Exertional markers were tracked.
Outcomes
VO2peak
VO2peak increased overall after 3 weeks of SIT.
p=0.03; no group difference p=0.98.
Sprint power
Average power increased in both groups but much more in high responders.
High responders +0.80 +/- 0.22 W/kg; low responders +0.22 +/- 0.19 W/kg; group difference p<0.001.
Exertion
Heart-rate intensity and lactate responses did not explain responder status.
Training HR 92.2 +/- 3.6% versus 94.6 +/- 4.6% HRmax, p=0.17; lactate group/test/time interaction p=0.95.
Insights
- Individual response should be tracked rather than inferred from effort alone.
- All-out cycling SIT is a high-strain protocol needing screening.
- Early sessions may require more recovery than later adapted sessions.
Limitations
- No control group
- Male-only sample
- Short intervention
- No gas analysis during SIT
- Lactate sampling missed immediate exercise peaks
- Technique and lifestyle factors not assessed
Safety
- No adverse events were reported.
- Medical screening excluded overt cardiovascular, pulmonary, metabolic, and chronic joint pain conditions.