Overlap



Palm facing downwards, horizontal circular motion on the offending side of the net.

Also known as "illegal alignment" or "out of rotation".

Same hand signal is used for improper server.

Rule
All players must be in the correct proximity to all the other players when the server contacts the ball:
 * 1 must be to the left of 6
 * 5 must be to the right of 6
 * 2 must be to the left of 3
 * 4 must be to the right of 3
 * 1 must be behind 2
 * 6 must be behind 3
 * 5 must be behind 4

After the server contact, the players are allowed to move (switch) positions.

See: Rotational Positions

Impact
In the 2015 PIAA District 2 boys consolation game (battle for 3rd), a team lost the first set 26-24 on a overlap call. They ended up losing the match 3-2. If the players had been in their correct position, they may have won the set (they had momentum) and the match. Because they lost, in their next playoff round (regionals) they faced the 2 time defending state champion and #1 ranked team in the state.