- Erector Spinae
- Gluteus maximus
- Lay back down with the arms alongside the body.
- Place one foot on the ball and push down with the heel.
- Keep the other foot extended.
- Keep the abdominals and lumbar region tightened.
- Lift the pelvis and bend the knee simultaneously until the toes are pointed.
- Return to the starting position without returning completely to the floor.
Keep the head aligned with the torso. Keep the back straight. Keep the abdominals contracted. Never lock the knees.