High-intensity interval training improves VO(2peak), maximal lactate accumulation, time trial and competition performance in 9-11-year-old swimmers
Question
How does 5 weeks of high-intensity swim interval training compare with high-volume swim training for performance and physiological outcomes in young competitive swimmers?
Summary
In competitive 9- to 11-year-old swimmers, 5 weeks of lower-volume high-intensity swim interval training improved competition points, 2,000 m time, VO2peak, and maximal lactate accumulation while using about half the swim volume of high-volume training. Both interventions improved VO2peak, and no overreaching symptoms were reported.
Methodology
- Healthy competitive young swimmers accustomed to more than four training units per week.
- 26 participants.
- Swimming intervals in a 50 m pool.
- Work intervals: Intervals ranging from 50 to 800 m in the main set.
- Recovery: Not clearly reported in the the paper.
- Intensity: 92% of personal best time for each distance.
- Warm-up about 400 m, 10-15 × 20 m technical drills, 30-minute main set, and cool-down.
- 5 sessions per week.
- 5 weeks.
- Randomized-order crossover intervention.
- Competition performance, Swim time trials, VO2peak and ventilatory threshold, and Maximal lactate accumulation were tracked.
Outcomes
Competition performance
LEN competition performance improved after HIIT but not after HVT.
HIIT +14.8%, p < 0.01, d = 0.48; HVT +5.8%, p = 0.28, d = 0.17.
2,000 m time
2,000 m swimming time improved after HIIT only.
HIIT -2.8%, p = 0.04, d = 0.21; HVT -1.8%, p = 0.33, d = 0.13.
VO2peak
VO2peak improved after both HIIT and high-volume training.
HIIT +10.2%, p < 0.01, d = 0.57; HVT +8.5%, p < 0.01, d = 0.46.
Lacmax
Maximal lactate accumulation increased after HIIT and decreased after high-volume training.
HIIT +20.1%, p < 0.01, d = 0.43; HVT -30.1%, p < 0.01, d = 0.51.
100 m time
100 m sprint time did not significantly change after either training block.
HIIT p = 0.17; HVT p = 0.22 in total sample.
Insights
- For trained youth swimmers, a lower-volume higher-intensity block can improve performance-relevant outcomes with less pool time than high-volume training.
- The protocol is sport-specific swimming coaching evidence, not a general youth fitness prescription.
- Monitoring for overreaching is important when increasing intensity in children.
Limitations
- Young competitive swimmers only.
- VO2peak was measured on a cycle ergometer rather than swim-specific oxygen uptake.
- Detailed interval-rest structure was not fully extractable from text.
- Short intervention with no long-term follow-up.
- Potential carryover despite breaks in a crossover design.
Safety
- Children and/or parents were asked to report adverse physical or mental reactions immediately.
- A computer-based psychological questionnaire was completed before each intervention session.
- No swimmers or parents reported overreaching/burnout symptoms after either training period.
- Protocol adherence was controlled with coaches' daily exercise log books.