Primary Muscle Group: Rectus Abdominis
Muscle Groups Worked in This Exercise: Rectus Abdominis and Obliques
Preparation: Place hands firmly on a stability ball about shoulder width apart as you lean forward with your body fully extended and supported by your feet and hands. You will be in a diagonal pushup position, leaning forward.
Breathing: Breath out on the contraction of the muscle and breath back in on the way back to the start position.
Execution: Once balanced in the extended position, drive your left knee upwards towards your chest and squeeze your core muscle group. Repeat and then switch legs.
Here are a few suggested alternative exercises:Ball Bottoms-UpBall Bridge LiftBall DeadliftSide Lying ScissorsStep Ups on Bench