Many players make beautiful, free-flowing practice swings.
But when the ball is sitting in front of them their swipes don't resemble their perfect rehearsals. Instead of accelerating through impact, they tense up, punching at the ball as if it could knock the club from their hands. Now remember the times you've tried subtracting a little distance from a shot by throttling back and swinging more easily. You probably surprised yourself with more distance than usual. In swinging more easily, you didn't tense your arms and hands before contact but remained relaxed, which let you accelerate through the ball.