Especially when looping, you need a loose arm to maximize power. Many players literally jerk their arm backwards when looping. Instead, relax it into a natural backswing position, and then use the natural elasticity of the muscles to slingshot your arm into your forward swing. Think of your arm as a rubber whip and whip it into the ball with smooth acceleration. You should extend this thinking to the entire body since looping is a full-body shot - with power coming from the legs, hips, waist, shoulder, arm, and wrist - all part of one big whip that smoothly accelerates into the shot. Watch the top players and do what they do!!!