Young footballers will soon be given red cards for deliberately heading the ball.
The safety initiative being trialled by The FA aims to reduce the level of brain damage seen in players.
New guidelines ban under-12s from heading in training and matches for the rest of the season.
To enforce the rule, referees will be able to show a yellow or red card for deliberate infringements, with the toughest punishment for preventing a goal by heading the ball.
Some grassroots coaches fear the new guidelines could lead to more teams playing long-ball football.
Mike Statham, an U12 coach for Hessle FC in Hull, said: “It’s going to ruin the game. Heading is a natural reaction in football. This trial is going to be an absolute mess.”
Repeated heading has been linked to neurodegenerative disorders.
A spokesman for the FA said: “We want to mitigate against potential risks. After the trial, the FA hopes to roll out the heading rule to all players under 12.”
