Like many of the others, I try to break up HITT training and have a day or two of other types of exercise between sessions. I like to change the medium and intensity of the workouts I do with my client throughout the week. For example, if we do HITT one day, we may do pilates/yoga and stability exercises the next. Then we may do a pyramid or endurance exercise. It depends on their goal and what their current level of conditioning is.