In 2016 US Soccer published its Player Development Initiatives. They have been mandated by US Youth Soccer as well. To see US Soccer's Player Development Initiatives,
Philosophy behind the Player Development Initiatives
US Soccer concluded the coaching and playing environment needs to be improved for 6-12 year olds
• Too much emphasis placed on the result of the game
• The priority should be to develop skills and abilities
• There is a need to educate and empower parents and coaches
It was in the context of these findings that U.S. Soccer has developed its new Grassroots Coaching Education structure.
More importantly it is incumbent upon LSA, all of our Clubs and the parents of our young players to understand that a results-oriented approach to the game is destructive to player development and contradicts coaching and player development philosophies around the world.
Small-Sided Game Standards Established
US soccer has also mandated that the following standards must be observed in all of our competitions. The Player Development Initiatives establish not only the following small-sided game criteria, but also establishes mandated ranges for the size of both fields and goals in each age group. 
The "Build Out Line"
In the 7 v. 7 format, there shall be a "Built Out Line" drawn on the field (see field diagram below). When the Goalkeeper gets possession of the ball, the opposing team must retreat behind the "Build Out Line". The Goalkeeper can roll, throw or pass the ball out with his or her feet. Punting and drop-kicking the ball shall not be permitted. After the ball is in play, the opposing team can once again cross the "Build Out Line". The "Built Out Line" will promote playing the ball out of the back in a less pressured setting and will encourage maintaining possession of the ball.
7 v 7 Field Diagram
With "Build Out Line"