Before you begin make sure that you are working with a partner who can catch the ball, (let the partner feel the medicine ball first so he or she knows how much it weighs and can prepare to catch it) or be sure that you have a solid wall or medicine ball rebounder that can withstand the forces of impact from a medicine ball.
Starting Position: Stand on the floor in an athletic ready position with both feet hip-width apart, position your body directly facing your partner (or wall / rebounder), your should be at least 5-8 feet away from your partner and each partner should maintain the spine in neutral (normal-to-flat), shoulders depressed (no shrugging) with scapulae retracted (squeezing shoulder blades together). Keep your chest lifted up, head in line with your spine or slightly extended (raised). Firmly hold a medicine ball between both hands right in front of your chest; contract and brace the abdominals and keep your hips pressed forward by contracting your glutes. Your head should be level and your eyes should be looking directly at the target.
The partner preparing to catch the medicine ball should stand with his or her feet firmly planted into the ground, the hips slightly flexed, the abdominals engaged and both hands held straight in front of the chest in order to provide a target for the partner throwing the ball. The person throwing the ball should step forward with the right foot into a forward lunge, as the right foot hits the ground bend your left knee to allow you to sink into your right hip simultaneously push the medicine ball away from your chest to throw it directly to your partner.
The partner catching the ball should catch it in a standing position with the arms outstretched straight out in front of his or her body, as the medicine ball hits the hands, allow it to decelerate towards the chest. Once the catching partner catches the medicine ball he or she should then step forward with the left leg into a forward lunge to throw the ball back to the partner who originated the throw who should be standing with the hips flexed, both feet hip width apart and the arms outstretched straight in front of his or her body to prepare to catch the ball.
The partner who originated the throwing should again step forward with his or her right leg into a forward lunge and throw the medicine ball back to the other person who is standing with outstretched hands prepared to catch the ball and step back into a forward lunge.
The partner catching the ball should first catch the ball with both hands and the feet hip width apart before stepping forward into a forward lunge with the left leg to throw another chest pass back to the partner who originated the lunging and throwing movement. Perform a number of lunge and throws stepping with one leg before alternating and conducting the same number of lunge and throws stepping forward with the other leg.
Exercise Variation: The partner catching the ball can balance on one leg to work on core stability while decelerating the forces related to catching the ball before stepping into the forward lunge.
During the entire thowing and catching sequence each partner should position his or her body with the spine in neutral (normal-to-flat), shoulders depressed (no shrugging) with scapulae retracted (squeezing shoulder blades together). Each partner should keep his or her chest held up and out, the head in line with his or her spine and both hands out front while preparing to catch the ball (holding the hands in front of the body gives the partner throwing the ball a target to aim for when releasing the ball; the throwing partner should keep his or her eyes on the catching partner's hands to ensure good aim).