Six Sessions of Sprint Interval Training Improves Running Performance in Trained Athletes
Question
Can six sessions of field-based sprint interval training improve running performance in trained athletes?
Summary
In 16 trained trail runners, six sessions of field-based 30-second all-out shuttle-run sprint interval training over two weeks improved 3000 m time-trial performance, maximal aerobic speed, and time to exhaustion. Because there was no control group, the results are suggestive rather than definitive.
Methodology
- Healthy trained trail runners with at least 3 years of running training.
- 16 participants.
- 30 m shuttle running.
- Work intervals: 30 seconds.
- Recovery: 4 minutes rest/walking.
- Intensity: Maximal all-out effort.
- Sprint block varied by number of bouts; warm-up included light contractions, 5 min aerobic exercise, and 6 progressive 20 m runs.
- 3 sessions per week.
- 2 weeks.
- One-group pre/post intervention
- 3000 m time trial, Maximal aerobic speed, Time to exhaustion, and Sprint output were tracked.
Outcomes
3000 m time
3000 m time-trial performance improved after six SIT sessions.
-50.4 s, about -5.7%, p<0.001, d=0.35.
MAS
Maximal aerobic speed improved modestly.
+0.41 km/h, about +2.8%, p=0.01, d=0.22.
Time to exhaustion
Time to exhaustion at 90% pre-intervention MAS improved substantially.
+158.9 s, about +42%, p=0.001, d=0.74.
Sprint output
Peak and mean sprint outputs improved across the intervention.
Peak output +2.4%, p=0.009; mean output +2.9%, p=0.002.
Fatigue index
Fatigue index did not significantly change.
p=0.17.
Insights
- A short field-based sprint interval block can be practical for trained runners when sprint quality and long recovery are prioritized.
- The protocol is not beginner-oriented because it uses all-out shuttle running and a trained athlete sample.
- The absence of a control group limits causal certainty.
Limitations
- No control group.
- Small sample.
- Short two-week intervention.
- VO2max was estimated rather than directly measured.
- Field tests are less precise than laboratory measures.
- No muscle biopsy, EMG, or direct VO2 measures were used to confirm mechanisms.
Safety
- Participants underwent routine medical screening.
- No adverse events or dropouts were reported in the the paper.