Medicine balls are great high-velocity training tools – they're the only weight in the gym you can throw at the wall or floor without wrecking the place. Throwing is one of life's most important full-body moves, and its explosiveness targets the core in a way no other move can.
Try: Ball Slams
With feet shoulder-width apart, hold the ball high above your head and simply throw it down at the floor right in front of you, hard enough that it bounces back up to where you can squat to catch it (medicine balls have very little bounce). Stand and repeat.