during a time out, between sets, or whenever the referee has stopped play. Serving Force, accuracy and fluid sequence of body movements are necessary to make full effect of the service. With a service, the server will attempt to achieve a direct point with it via an "ace", or will at least hope to force the opponent into a difficult first hit, thereby affecting the buildup of the opponent's return hit. The ball is hit mostly with the inner surface of the fist, due to control. However, if the server wishes to hit the ball with full force, they will use the edge of a clenched hand. This is called a "hammer hit", and carries greater risk of failure due to the smaller impact surface than the inner surface of the fist. The server will attempt to hit the ball into an area on the opposition's side of the field that will be difficult for the opposition to return. For example, this can be done by hitting the ball long to the back line, directly at the feet of an opposition player, diagonally across the court, or with a short ball just over the net. A difficult, yet highly effective variation to the serve is to add curve to the hit. This can be done by sweeping across the ball from left to right, or vice versa, when hitting with the inside surface of the fist. If done correctly, the ball should appear to curve away from or into the opposition, confusing their return. When preparing to serve, the server must stand behind the service line (3-meter line). Upon completion of the service hit, the server's first contact with the ground must be behind the service line. For example, if the server jumps while serving, the first foot to touch the ground upon landing must be behind the line. The second foot may then land in front of the line. This same rule applies for standing serves. If this is not correctly complete, the server will be charged with a fault, and the opposition will receive a point. In addition, the ball must visibly leave the hand prior to hitting (i.e. it must be thrown). It must not be pushed away out of the holding hand in an attempt to surprise the opponent, as this will also count as an error. Defense The defender must be skillful in order to