In playing from the hazard, Pettersson brushed the grass during the backward movement of the club. However he also touched, and moved, a leaf that was not attached and therefore a loose impediment. This is a breach of Rule 13-4c, which states that a player must not touch or move a loose impediment before making a stroke at the ball when both the loose impediment and the ball are in the same hazard. If he does, it is a two stroke penalty. The Definition of a Stroke is the forward movement of the club with the intention of striking at and moving the ball. The backswing is not a part of the stroke. Therefore moving a loose impediment in the backswing is a violation of Rule 13-4c. Since Pettersson moved the leaf prior to the forward movement of his club, and was in breach of Rule 13-4c, he was assessed a two-stroke penalty. Since Rule 13-2 (Improving Lie, Area of Intended Stance or Swing, or Line of Play) does not prohibit the movement of loose impediments that Rule did not apply.