Ask the children to form a line each one facing you.
Turn your back on the children at a fairly good distance. While your back faces the children, they need to run forward as fast as they can, because the goal of the game is to be the first to touch you.
But when you shout “1,2,3, apple!” and turn around to face them, the children must stand still. If a player moves, he must return to the starting line. The game ends when a child manages to touch you.