The 6-foot-6 Juan Martin del Potro awes opponents with his flat forehand. Before he hits it, he immediately turns his shoulders and tiptoes around the ball in small, rhythmic steps. "It's unique for a guy his size," Macci says.
The lesson: Take small steps when you're near the ball so you can put yourself in position to swing the same way. Watch how del Potro puts his non-hitting arm across his body before he swings. "That pretty much ensures that you have turned and coiled enough," Macci says.