Grab a medicine ball that will give you a workout (not too easy or hard) With your legs shoulder width apart and knees a little bent, hold the ball tightly over your head. Bring it down in from of you and let it "bounce" about an inch over the floor. [If you let it hit the floor hard while holding onto it, I believe the friction forces will travel up your arm to your spine, skull and brain, and you don't need that.) Bring the ball back up over your head in a moderate speed and about two to four inches behind your head (with arms straight up). Repeat for four sets of ten repetitions if you can.