Looking at Xander Schauffele's driving stats, you probably wouldn't guess his size (5-10, 175 pounds). Schauffele averaged 305 yards off the tee on the PGA Tour in 2018, which prompts the question of how he's able to keep up with—and sometimes outdrive—tour pros who are a lot bigger and stronger. Turns out, it's not because he's trying to swing as hard as he can."We don't want him swinging any faster; that's been optimized," says his father, Stefan, who has been Xander's only swing coach. "The key to his power is the width of his swing arc. That wider the arc, the more time he has to gather clubhead speed into the ball."