From Ergo Log
Even more explosive exertion, for even shorter bursts, with even shorter rests in between: according to sports scientists at Lillehammer University College in Norway this is the best way to make interval training even more effective.
The Norwegians did an experiment for 10 weeks with just under twenty well-trained cyclists. All the cyclists did interval training for about 40 minutes twice a week. They combined the interval training with their regular training.
Half of the cyclists did more or less classical interval training: cycling for 4.5 minutes as fast as they could and then 2.5 minutes cycling gently to recover. They repeated this cycle until the 40 minutes were up. [LI]
The other half of the cyclists did a more explosive kind of interval training, with shorter cycles: they cycled as fast as they could for 30 seconds and then cycled gently for 15 seconds. They repeated this cycle for 9 minutes and then rested for 3 minutes. Then they started a second series, completing a total of 3 series. [SI]
Both interval-training schemes were equally intensive. The amount of effort the cyclists expended was the same for both kinds of interval training and the cyclists experienced them as equally tiring. But the training with the shortest intervals was more effective.
The VO2max of the cyclists in the SI group increased significantly, whereas it did not for the cyclists in the LI group. Maximal oxygen uptake (VO2max) is the most important predictor of endurance capacity.
The cyclists who did the SI interval training also developed more power and were therefore faster. The LI training on the other hand had little effect in this department.
“The present study indicates that performing the present SI protocol during the high-intensity interval sessions induces superior training adaptations after 10 weeks compared with performing high-intensity interval sessions with a more classic LI protocol constituted by 4 × 5-min work intervals”, the Norwegians wrote.
Scand J Med Sci Sports. 2015 Apr;25(2):143-51.