Reverse Crunch Tackle your lower abs with this fun variation of a crunch. Lie on your back on the floor. Place your hands on the floor beside you. Bring your knees in toward your chest with your feet together. Use your abs to slowly curl your hips off the floor and into your chest, then slowly lower them back to the starting position to complete one. Repeat for one minute. Don't swing your legs to create momentum; use your abs to control your movement. Repeat 2-3 times. Image Source: POPSUGAR Photography