Male endurance cyclists (N = 20) were exposed to interval training of varying
intensities and then assessed for any effects
on a 40-km time-trial.
Ss were first measured on a 25-kJ sprint test, an incremental test to determine peak aerobic power, and a simulated 40-km time-trial on a Kingcycle ergometer. Five randomly selected groups were formed, each featuring a different format of interval training: 12 x 30 seconds at 175% peak aerobic power; 12 x 60 seconds at 100% of peak aerobic power; 12 x 2 minutes at 90% of peak aerobic power; 8 x 4 minutes at 85% of peak aerobic power; and 4 x 8 minutes at 80% of peak aerobic power. Six sessions were completed over three weeks in addition to usual aerobic base training. All measurements were repeated.
The greatest effects were observed in the 85% and 175% groups. Intervals performed at 80% , 90%, and 100% did not produce
performance enhancements.
This investigation hints at the value of moderate, relatively continuous work of stimulating nature (85%) and very-short interval work (175%) as being the most effective training formats/
intensities.
Implication. Interval training performed at close to race pace intensities, enhance 40-km time trial performance (an example of the principle of specificity). Intervals at 175% peak aerobic intensity also improve performance, but by a different and presently unexplained mechanism.