A recent 8-week study compared the effects of three types of running interval training formats on V̇O2max in aerobically well-trained men.
The researchers also investigated the protocols’ effect on 1. anaerobic capacity; 2. long-distance running performance, and 3. sprint endurance performance.
The study compared:
HIIT = 4 × 4 min at ~95% maximal aerobic speed (MAS) with 3 min active recovery periods
SIT 1 = 8 × 20 s (~150% MAS) with 10 s passive recovery periods. The aim was to exhaust the participants during the final interval
SIT 2: 10 × 30 s of maximal effort (~175% MAS) with 3.5 min active recovery periods
The sprint interval protocols were not performed ‘all out’ (as fast as possible)
Results
– HIIT 4 × 4 min increased V̇O2max more than the two SIT protocols
– SIT 8 × 20 s also improved V̇O2max more than SIT 10 × 30 s.
– HIIT 4 × 4 min enhanced long-distance (3 km) performance more than SIT 10 × 30 s
– SIT 8 × 20 s increased anaerobic capacity more than HIIT 4 × 4 min
– Anaerobic capacity (maximal accumulated oxygen deficit) increased following SIT, 8 × 20 s, but not after HIIT (4 × 4 min), or SIT (10 × 30 s).
– Long-distance (3km) endurance performance increased in all groups (HIIT 5.9%; SIT 4.1%; SIT (10 × 30s): 2.2%),
– 300 m run performance exhibited within-group increases in SIT, 8 × 20 s (4.4%) and SIT 10 × 30 s (3.3%).
Take home
The results of this study are consistent with previous research as HIIT was more effective at improving V̇O2max and aerobic endurance performance than SIT. The superior improvement in V̇O2max after HIIT 4 × 4 min probably occurred due to a greater overload on the cardiorespiratory system skeletal muscles.
Study: Hov et al. (2023). Aerobic high-intensity intervals are superior to improve V̇O2max compared with sprint intervals in well-trained men. Scandinavian Journal of Medicine & Science in Sports.
https://onlinelibrary.wiley.com/doi/epdf/10.1111/sms.14251
Paul Hough ,Sport and Exercise Scientist exerciseandsportscience.com