Many physical activities, especially those in which an individual is exposed to high/sudden forces require a warm-up. HIIT is however different. The forces that the musculoskeletal system is exposed to during a HIIT workout are relatively low and there is never a sudden increase in force during HIIT exercise. Even so, there is still a hidden warm-up for each exercise in HIIT. The initial 30 or so seconds of a properly applied HIIT set is the warm-up for the more intense, later part of the set to come- the efficiency of HIIT shines through again.