Advanced core stability and abdominal exercise.
- Sit straight up on the exercise ball then walk your feet forward until your back is resting around the ball. Put both hands behind your ears, and keep your elbows out. Your feet should both be flat on the floor.
- Exhale and crunch forward, bringing your left knee up.
- Continue to extend the knee towards your head. Hold for 2 seconds and release. Repeat with opposite leg for one full rep.
- Do 10-12 reps each leg. Take your time with this exercise. It is more difficult to balance if you are going too quickly.