High-intensity interval training (HIIT) on Friday can serve as a supplementary moderate-intensity workout for leg muscles.

“However, on Friday, I do a high intensity interval training session that serves two purposes. One is it serves the purpose of triggering a certain type of endurance and getting my heart rate very, very high. And in addition to that, because of the way I do that workout, it acts as a sort of supplement or a more moderate intensity workout for quadriceps, hamstrings, and calves, such that I at least never lose strength, and in fact, generally build strength from one leg workout to the next, provided I'm doing things correctly.”