8 Minute Lower Body Circuit Training Circuit training keeps your heart rate up as you move from exercise to exercise, so you burn fat and tone up quickly! A circuit is the completion of all exercises in the routine, one after the other, with little to no rest between exercises. Each completed circuit is followed by a short rest period. This workout focuses on firming your thighs and glutes, all while burning excess body fat. Get ready to lunge and squat your way to a gorgeous lower body!