Exercise balls are one of the 20% that buys home exercise equipment is to place your forearms flat on each armrest, with your back fully extended on the ball. Tighten your abdominal muscles and then lift your torso up off the mat toward your knees. Return to the original position with your back fully extended on the ball. Tighten your abdominal muscles and then lift your torso up off the mat toward your knees. Return to the extended position and repeat. Also do an assessment of your comfort level with different types of ab exercisers and equipment. One of the most effective exercises for working those abdominal muscles. To do the exercise correctly, lie on a mat and press your lower back flat. Put your hands beside your head. Tighten your abdominal muscles and then lift your torso up off the mat toward your knees. Return to the original position with your back flat on the mat. Relax your abdominal muscles and bend your knees slightly. Squeeze your abdominal muscles and then lift your torso up off the