[header] How to do a knee raise with an exercise ball [title] Take your exercise ball and place it where surrounding objects won't obstruct your exercise. [title] Sit down on the exercise ball with your legs in front of you, knees bent and feet on the ground. [step] Walk yourself forward slightly if you're not comfortable, but don't fully lean back against the ball. 
Point your arms straight out (so that your wrists, elbows, and shoulders are aligned). Inhale and you should be in a neutral position.