Stand back-to-back with a partner. Place your feet hip-width apart, pull your abs in tight, and keep your back straight. One person holds the medicine ball (or unweighted ball), keeping elbows bent and the ball close to the body.
EXHALE: Keep your feet planted and twist (from the waist) toward each other. Pass the ball to your partner. INHALE: Both people return to the starting position, facing forward. EXHALE: Twist to the opposite side and receive the ball from your partner. INHALE: Return to the starting position, facing forward, to complete one rep.
When twisting, rotate from the waist and keep your back straight and abs engaged. Hold the ball close to your body.
Muscles Worked: Abs, Obliques