No prob. rca gave a good run down of it, so I'll try to hit it from a different perspective. It starts out at the very youngest ages: 4-6. Where their coaches will assign L/C/R defense and L/C/R offense. Sadly, I've seen this at the very first practices kids attend. It doesn't have to be this exact set up, but the effect will be the same. Then the "lesson" goes on to tell them that they stay in this area until the ball comes near them, then they do something: Go get it, defend, attack. This is all to fight their natural urge to swarm the ball. But making them stay in their "areas of responsibility" is completely the wrong thing to teach them at this stage, because it creates a mentality of "yours or mine" and not "ours". The idea in soccer is to defend and attack as a unit or small groups. Positions for young players create this mentality where "I'm on offense, I don't need to win the ball back." or "I'm left wing, I'm not going to move closer to the ball if it's all the way over there." or "I'm left defense, the center defense will handle that attacker." At the beginning stages, we can't teach kids to defend in pairs or threes yet, BUT placing the idea that we're individually responsible and that our responsibilities are specific (as opposed to universal) are habits that are hard to break down the road. In contrast, let's say we teach shape. In a diamond, there are still "positions": there always has to be a top, bottom, and the two sides of the diamond. So there are positions and they always have to be filled, but we don't name which player stays in these spots. It's a fluid, dynamic system—much like grown up soccer. The diamond can move all over the field, whereas the other system leaves the majority of players in areas of zero action. In all my years of playing, reffing, coaching, and just watching youth soccer I haven't seen a consistent, intentional switch of the attack to beat teams that have overcommitted to one side before U14. The reason grown ups are more disciplined positionally is because at a certain age, players can recognize this weakness and exploit it. Once they do, it's much easier for the 13 YO brain to adjust to not getting sucked out of position, than it is for them to learn to go to where they are needed. Can you teach dynamic, thinking soccer with positions? Sure. I just see it rarely done well. Again, it's not the positions but how soccer is taught in relation to positions. In the US, we get into the ideas of formations and systems too early. There are simple, fundamental systems (see diamond explanation above) and there are complex, adult systems where there are responsibilities and if-then decisions that need to be made. Coaches are so afraid of swarm-ball, but I believe the aim is to get to a modified version of swarm ball at advanced levels. Modern theory says that the player on the ball should have at least 3 or 4 passing options. So if it's 4 passing options, plus a player on the ball that's 5 players. 50% of one team's field players are in the vicinity of the ball, attracting who knows how many defenders. If you watch the kickoff of a modern, professional soccer game all 20 field players are in a 15-20 yard area of midfield. Watch a kid's game at kickoff and players are spread to the top of each penalty area. Why? They are effectively useless all the way back there. Another problem is that when positions are taught they are taught in lines. Defensive line, midfield line, forward line. Soccer is not horizontally linear. It is an angular game. sorry long winded.