What is the proper procedure for a throw-in?

The proper procedure for a throw-in is that the player must use both hands to throw the ball from behind the head while keeping both feet on the ground. This technique ensures that the ball is thrown in a way that adheres to the Laws of the Game, promoting fairness and proper execution of the throw. Holding the ball with both hands and delivering it from behind the head allows for a fluid motion that is consistent and allows for greater control of the throw. Additionally, keeping both feet on the ground is vital to prevent any illegal movement or lifting that would result in a foul, maintaining the integrity of the game.

The other options do not meet the established guidelines for performing a throw-in, as they either do not use both hands or do not follow the required motion, potentially leading to confusion or unfair play.