Interval training for endurance athletes

If you are an endurance athlete, you are probably aware of the benefits of high intensity interval training (HIT). If you are not aware, interval training entails training at a higher intensity (percentage of maximum effort) to allow for greater physiological adaptations. The benefits of interval training, specifically for endurance athletes, include increased VO2 max, peak power output, ability to buffer lactic acid and the performance benefit of improved race times.

Many training programs focus on the long duration, low intensity training to gradually adapt to training and once the athlete is more accommodated, moderate and high intensity workloads are performed in order to improve some performance. Much like strength athletes, endurance athletes can benefit from systematically organizing their training to focus on improved performance. When using HIT workouts, there are many ways to integrate it: 1-3 times a week, shorter duration versus longer duration, number of sets performed, etc. A recent study on elite Norwegian cyclists wanted to evaluate the effectiveness of these different programming techniques on performance.

The cyclists performed the same overall workload throughout the study, in 3 different periodization schemes: decreasing intensity, increasing intensity and mixed intensity. The decreasing intensity started out performing HIT sessions at short duration and high intensity and gradually decreased the intensity of the workouts while increasing the duration. The increasing intensity group performed the opposite workouts and the mixed training performed a combination of shorter duration higher intensity and longer duration lower intensity HIT sessions.

At the end of the study all 3 groups had increased peak power output, increased VO2 max and faster times in their time trial with no single model being superior to the other two. The take home message is that once a foundation of long duration low intensity exercise is performed, athletes can benefit from incorporating HIT into their workouts.

Conclusion:
There are significant performance benefits of performing 2-3 HIT sessions a week in conjunction to regular low intensity long duration training for endurance athletes.
 
Reference:
Sylta, O. et. al. (2016). The effect of different high-intensity periodization models on endurance adaptation. Medicine and Science in Sports and Exercise. http://journals.lww.com/acsm-msse/Abstract/publishahead/The_Effect_of_Different_High_Intensity.97486.aspx