Yuri Elkaim, personal fitness coach, shows you a five-exercise Bosu Ball workout that will tone your abs fast. The first exercise is a pushup on the Bosu Ball with the spherical side down. With your torso down, lift one leg up from the floor. Bring the torso down, then back up, and pull the raised leg into your body, then back out. Alternate legs each time, and do as many of these as you can. In the second, turn the Bosu Ball flat-side down and align your buttocks and back on top of it so that you can balance on the ball with no limbs touching the ground. Bend your knees, legs and arms pointing up. Then point your left leg and right arm straight out, then pull them back in. Alternate arms and legs, and repeat as many times as you can. Next, with the ball's flat side still down, balance your front on top of the ball. It's important to find the right balance point. With your hands by your head and your legs straight out, lower your legs and head to just above the floor, then raise until your body is flat. Repeat this step as many times as you can. This should be a very rigid, controlled motion. Try to do this for at least a minute. For the fourth exercise, balance your buttocks on the top of the ball again, and pull your knees into your torso. Extend your body flat, then bring your knees back in. Again, do as many as you can. The last exercise involves finding that same balance point for your backside, and extending your arms and legs out, keeping everything raised off the ground. Pull your right arm and left leg in, keeping them straight, and back down. Switch to your left arm and right leg, and alternate as many times as possible. This is called the alternating jackknife. Following these five simple steps with your Bosu Ball will give you a core abdominal workout that will last no more than ten minutes.