First, when he is cocking the back the football chemical energy from his muscles is used. This creates motion, and the chemical energy is transformed into kinetic energy. Next, when the ball is at the back of his head, he use chemical energy from his muscles to throw the ball. This creates motion again and that chemical energy is now kinetic energy. All that energy becomes gravitational potential energy once te ball left his hand. Thent he ball in the air until it reaches my hand, then is turns into thermal and sound energy. we know that because it made a sound when I caught the ball, and the i felt heat from the ball when it on my hand. we know all the energy is gone from the ball because it stop moving.