Players at Manchester City and Liverpool are set to use special mouthguards in training to assess the impact of heading the ball.

Already used in rugby, the mouthguards are able to collect data in real time and show how impacts affect the brain.

It will form part of a Premier League research project after concerns about the long-term dangers of heading.

In 2019, a study found professional footballers more likely to suffer from neurodegenerative brain disease.

The Premier League wants the research to be completed in months after accusations that football has been slow to act.

However, concussion substitutes and restrictions on heading in youth football have already been introduced this season.

On Tuesday, the Football Association's chief medical officer Charlotte Cowie said football was "moving towards" changes to heading in professional training.

She said that the governing body's research taskforce had recommended that youth team players "would only head the ball a maximum of 10 times in a training session, once a week".

She added that similar changes to the professional game were "contingent" on how effective youth heading guidelines are with coaches and the success of the Premier League research.

Cowie explains that the "integrated mouthguards" would help "understand types of header" where forces might be different depending on how far the ball had travelled before impact.

"We want some more detail on that before we rule on the professional game, but we fully intend to do that and also in the adults grassroots game," she added.