Stand facing partner, throwing distance apart with one foot forward. First person holds medicine ball with both hands against chest. Partner has arms in front, ready to receive ball.
First person throws medicine ball to partner's chest by forcefully extending both arms forward. Partner catches ball in front of chest with both hands, recoils ball toward chest, and immediately throws ball back to first person in same manner. First person catches ball and repeats volley. Continue to throw ball back and forth.