Bridge 4 is a strength and conditioning workout that requires attention to form and focus to maintain execution intensity. Its steady, studied approach to exhausting peripheral and core strength means that your body temperature will start rising steadily as you enter the sweatzone. The workout's structure will then keep you there until you reach the very end. Throw punches properly, bending your knees to drive the uppercuts and swivelling on the ball of the foot that's on the side of the arm throwing the punch to throw your entire body behind the punch and you'll feel its effects.