This is a terrific exercise to practice responding to very close-range threats and improving reflexes. Go buy one of the rubber snappy hands from a vending machine, and have your partner stand in front of you with it. You can start off about five feet apart, and decrease your distance as you improve your reflexes. Have your partner snap it at various parts of your body – your goal is to dodge it as much as possible. If boxing is your game, this is a perfect exercise. Try to isolate your torso and bend / duck out of the way without stepping back. You may also have your partner vary the length of the cord on the hand – shortening it will allow the snapping to occur faster, making the exercise more difficult.