Exercise Instructions:

  1. Place a Swiss ball between your ankles and grip it with your legs.
  2. Switch your abs on before starting every rep.
  3. Bring your legs and arms up, passing the ball form one to the other and lowering it overhead.
  4. Repeat the process, heading the other way.
  5. If you find holding the ball tricky (some gyms only have massive ones), this is still an effective exercise if you remove it completely and mimic the movement pattern anyway.

Muscles Worked: