This no-equipment HIIT workout involves 45 minutes of high-intensity circuit training broken into 3 15-minute segments, one focusing on abs, one on lower-body and one on cardio. You will need less than 1 hour to complete this workout.

This no-equipment HIIT workout involves 45 minutes of high-intensity circuit training broken into 3 15-minute segments, one focusing on abs, one on lower-body and one on cardio. You will need less than 1 hour to complete this workout.