HOW MUCH TIME IS INVOLVED?
Amazingly, HIT requires only a few weeks to hone that performance edge. One study indicated that as few as four sessions were needed to measure a benefit, while another measured an increase in peak work outputs of 4 to 5 % and simulated 40 km time trial results of 3 to 3.5% after 6 sessions. And these improvements were independent of a change in VO2max.
HOW MANY INTERVALS PER SESSION?
One suggestion was to apply 15% of weekly training milesto HIT. These miles were divided into 6 separate sessions of six to eight 5 min repetitions at 80% of peak power output followed by 60 second rest intervals. Another used twenty 60 second intervals with a 120 second rest. And a third incorporated repeated supramaximal sprinting into the training program with equally good results.
HOW HARD SHOULD I PUSH?
Your personal maximum power output is the ideal for interval intensity and 60% of your personal time to exhaustion is a good interval duration. This combination significantly improved 40-km time trial performance. If you don't know your personal maximum power output, VO2Max can be substituted for intensity of effort.
AND A TAPER IS THE KEY TO SUCCESS
HIT should be the final step in your training program with 4 to 6 interval sessions over 2 weeks. Although relatively short, it does have one risk - overtraining fatigue. To get maximum benefit, HIT must be combined with a tapering of your training program. There is suggestive evidence that a slow taper may have an edge, but this is contoversial. What is clear is that a 50% single-step reduction in HIT led to an approximately 6% improvement in simulated 100 km time-trial performances after 2 weeks.
Most coaches have interpreted a taper as a decrease in training volume (time) rather than the intensity of each interval session. But a recent study has challenged that perception. In that study, two groups cut their training time by 50 %. One maintained a steady program at 68% VO2max while the other did sprints keyed to their lactate threshhold and averaged 83% VO2max. At 21 days there was no difference in performance measures.