Effects of High-Intensity Interval Training Versus Sprint Interval Training on Factors Related to Endurance...

Area of Science:

• Exercise Physiology
• Sports Science
• Training Methodology

Background:

• Endurance performance is crucial in many sports.
• High-intensity interval training (HIIT) and sprint interval training (SIT) are popular training methods.
• Comparing the long-term effects of HIIT and SIT on endurance is important for optimizing training.

Purpose of the Study:

• To systematically review and compare the long-term effects (≥2 weeks) of HIIT versus SIT on endurance performance-related outcomes.
• To analyze factors that may moderate the effectiveness of these training methods.

Main Methods:

• Systematic literature search of Web of Science, PubMed, and SPORTDiscus databases.
• Meta-analysis of 12 randomized crossover trials involving 460 subjects.
• Random-effects model with standardized mean difference (SMD) calculation.

Main Results:

• HIIT significantly outperformed SIT in improving maximal oxygen uptake (V̇o2max) and maximal aerobic power/velocity (MAP/MAV).
• Longer HIIT protocols (>8 weeks) and longer work intervals (>4 minutes) showed significant benefits for V̇o2max.
• HIIT led to greater improvements in time trial performance in moderately trained individuals.

Conclusions:

• HIIT demonstrates superior improvements in aerobic capacity compared to SIT, especially with longer intervals and durations.
• Athletes and coaches can consider specific HIIT protocols (3-6 intervals of 4-5 minutes at 80-95% MAV, 2-3 sessions/week) to enhance aerobic capacity.
• While most outcome quality was low/very low, MAP/MAV quality was higher, supporting HIIT's efficacy.