Apologies for the belligerent title, but here is my rationale behind it. As ever, I’m happy to evolve my thinking in terms of counter-arguments which I’m not yet aware of.
By five-a-side, I mean the specific set of rules as per https://en.wikipedia.org/wi...
I don’t mean small-sided games, and I definitely don’t mean futsal. I love futsal.
1. Defenders are not allowed to go into the penalty area. This contradicts the defensive principles of play which we are trying to teach young players.
2. Goalkeepers are not allowed out of their D. This restricts creative options for goalkeepers and inhibits their technical development, specifically with regard to footwork under pressure and reading of the game in terms of when to play as the last defender.
3. Attackers are restricted from making clever movement in and around the box.
The above three make 5-a-side a Part Practice, by definition.
4. The size of the goals is not conducive to players being challenged to come up with good solutions to allow them to score in narrower goals. They also thwart the development of young goalkeepers by being unrealistically wide.
5. Having walls along each side of the pitch makes players lazy in possession.