Principles of Interval Training: A Practical and Physiological Teaching Guide for Educators

We teach that physical activity, exercise, and exercise training are good for us, and that the positive effect is better if we exercise with intensity; the greater the intensity the greater the effect. Indeed, there is clear and irrefutable evidence of intensity-dependence of effect, stemming from a dose-response relationship between effort going into the exercise and the result coming out of it. This leads to the situation where we generally and practically prescribe exercise as intensely as possible, for as long as possible, but this comes in conflict with the speed/power-duration relationship that dictates how long high-intensity exercise may be sustained. The solution we have is high-intensity interval training, referred to as HIIT or just interval training. This is a modality of exercise training that with repeated bouts of high-intensity exercise interspersed by active/passive recovery periods permits accumulation of intense exercise beyond that which would be achievable in a single exercise bout. This is then applied to a range of exercises and locomotion modes. However, while we often refer to and teach concepts of intensity-dependence of exercise training effects, we rarely describe the basics of the actual exercise. Here, we introduce interval training, and by association, intensity, for the physiology-savvy, but non-exercise science educator. We conceptualize the principles of interval training and provide a practical framework and lesson plan for teaching appropriate interval training.