High-Intensity Interval Training Improves Cardiovascular Fitness and Induces Left-Ventricular Hypertrophy During Off-Season
Question
Does a 7-week off-season running HIIT program improve fitness, performance, and cardiac morphology in young amateur dinghy sailors?
Summary
In eight young amateur sailors, 7 weeks of supervised running HIIT during the off-season improved VO2peak and running performance and increased some cardiac wall-thickness measures. The study was small and uncontrolled, so the cardiac findings should be treated as preliminary athletic adaptation evidence.
Methodology
- Young amateur dinghy sailors
- 8 participants.
- Indoor-track running.
- Work intervals: 200 to 1000 m repeats.
- Recovery: Sitting or slow walking recovery.
- Intensity: 95-145% of 2000 m velocity depending on distance.
- 36 to 106 min depending on week.
- 3 sessions/week.
- 7 weeks.
- Single-arm longitudinal intervention study
- VO2peak, Running performance, and Cardiac morphology were tracked.
Outcomes
VO2peak
VO2peak increased after 7 weeks of running HIIT.
44.1 +/- 7.2 to 46.2 +/- 8.3 mL/kg/min, p=0.02.
Performance
Running performance improved in the 200 m and 2000 m tests.
Exact values were reported in the article tables; both performance tests improved.
Cardiac structure
Left atrial diameter and LV wall-thickness measures increased, while ejection fraction stayed normal and unchanged.
LA diameter 32.0 to 33.5 mm, p=0.01; LV posterior wall 7.5 to 8.2 mm, p=0.01; septum 7.6 to 8.6 mm, p=0.02.
Insights
- Performance-based pacing can scale running intervals for athletes.
- High adherence may reflect supervised team-like athlete context.
- Cardiac adaptation claims require controlled replication.
Limitations
- Small sample
- No control group
- Athlete-only population
- Only two female participants
- Short duration
- Cycle test used after running training
Safety
- No adverse events or injuries were reported.
- No detailed adverse-event monitoring method was described.