The game is modified for younger players based on their ability to learn.
U5 and U6 - The game is 3v3 with no goalkeeper. This means do NOT KEEP A PLAYER BACK. We are trying to teach ball skills and agility. Posting a player in front of the goal prevents them from participating in the game, it denies them "touches" on the ball, and children of this age want to be involved in the game. Most players are not ready for teamwork concepts such as passing.
U7 and U8 - The game is 4v4 with no goalkeeper. Again, this means a player should NOT BE POSTED IN FRONT OF THE GOAL. The emphasis is still on skills, but players are learning very basic teamwork, including passing and helping each other on defense. A player stationed in front of the goal box is, as with the younger ages, denied touches on the ball. As coaches, our job is to begin teaching teamwork, defensive maneuvers. Having a player standing and waiting is NOT conducive to learning soccer.
U9 and U10 - The game is 6v6 including a goalkeeper for the first time. Players are passing more, improving quickly in their skills, have defined playing positions, and are more physical.
U11 and U12 - The game is 8v8 including goalkeeper. Players are growing in skills, teamwork, and positional play. They are beginning to understand the value of communication and starting to specialize in playing positions.
U13 and older - For the first time, the game is 11v11 on a full-size field. As a result, players must know each others' capabilities and work together to be successful, while still polishing their skills.