- The flat side of the half ball should be on the ground with the round part facing up. To do a crunch on a firm half ball, lie with your center and lower back on the ball, with knees bent at a 90 degree angle in front of you and hands clasped behind your neck for support. If this is too difficult at first, bring your knees closer to your body. Flex your abdominal muscles and raise your shoulder blades up towards your knees, bringing your hips slightly up at the same time. Slowly lower back down. Do one to two sets of eight to 12 repetitions of this exercise.
- You can use either side of the firm half ball for these exercises, however having the flat side up will allow for a wider stance of the hands. For the plank, place your hands about shoulder width apart on the ball with your legs straight out behind you and feet on the floor. Your abs should be tight. With your arms straight but not locked, hold your body up for 30 seconds. Rest for 1 minute and repeat. To do push-ups on the firm half ball, use the same position as for plank but do slow, controlled push-ups. The biggest challenge of these push-ups is to maintain balance. Do one to two sets of eight to 12 push-ups.
- There are a couple of ways to use the firm half ball for squats and lunges. The first is to stand on the floor with the ball curved side up in front of you. With hands on the hips or out to the side, step with one leg onto the ball, bending that knee to a 90 degree angle and then stepping back. Repeat with the other leg. The knee should not go past the foot beneath it. Do about 10 repetitions with each leg. For squats, stand on one side of the half ball. Side-step both feet onto the ball and squat down. Raise the body up in the same motion and side-step to the other side of the ball. Repeat 10 times. For an extra challenge, do squats with the flat side of the ball facing up. These squats require extra control and balance.
