New guidelines on limiting heading in football are "extremely welcome", campaigner Dawn Astle says.
A neuropathologist said that the death of Dawn's father, the former West Brom striker Jeff Astle, was due to a brain condition caused by heading footballs.
Professional players in England will be limited to 10 "higher force headers" a week in training from this season.
"It's one of the most important days in many years of fighting against the business of football," she said.
Astle has previously pushed for research into a link between football and brain injuries, and worked with the Professional Footballers' Association on an advisory basis to help "shape the longer-term neurodegenerative care provision for former members and their families".
However, while she welcomes the new guidelines, she remains "worried that this is focused on what they call 'high force heading' when the effects of repetitive, low impact heading is equally concerning".
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An MPs' inquiry earlier in July, carried out by the Digital, Culture, Media and Sport committee, said that sport has been allowed to "mark its own homework" on reducing the risks of brain injury.
Responding to the new guidelines, committee chair Julian Knight said: "We are pleased football is taking precautionary action following our inquiry on concussion in sport but it is a shame that the science on which this guidance is based seems to be unpublished.
"Without this, it is not clear how football arrived at the chosen header limits. Football should base protocols on independent advice from those outside of the game. Without that, even decent change is just another example of football marking its own homework."
Why have the new rules been announced?
A study in 2019 found that professional footballers are three and a half times more likely to die from dementia than people of the same age range in the general population.
Members of England's 1966 World Cup-winning squad including Jack Charlton and Nobby Stiles have died after suffering from brain functioning diseases believed to be linked closely to heading footballs.
Last year, it was confirmed that Sir Bobby Charlton, another World Cup winner who played for Manchester United, is suffering from dementia.
In March, Hayley McQueen called for a limit to heading after her father, former Scotland defender Gordon McQueen, was diagnosed with vascular dementia.
What do the new rules say?
The guidelines announced on Wednesday come after "multiple studies" were conducted into concerns about the long-term dangers of heading.
As well as the new rules for the professional game, guidance for amateurs is "10 headers per session and only one session a week where heading practice is included".
That guidance is for clubs "up to and including step five of the National League system and tier three and below of the women's football pyramid, and is specifically tailored for this level of the game".
New guidelines for children aged 11 and under were announced in February. They are no longer taught to head footballs during training in England, Scotland and Northern Ireland, while guidance for older children is that coaches limit how much heading they should do.
"Our heading guidance now reaches across all players, at all levels of the game," said the Football Association's chief executive Mark Bullingham.
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Football and dementia expert Dr Michael Grey noted that there is no gender-specific guidance "despite growing evidence that women are more susceptible to head injury than men".
"There are biological differences between male and female in both structure and physiology that warrant a more considered approach," he said.
"Furthermore, there has been no change in the guidance for children. This is problematic due to the fact that the brain of a child is at significantly greater risk to brain injury than that of an adult.
"It is time to consider an outright ban on heading the ball for younger children - both in practice and match play."
How will they work?
A joint statement from the FA, PFA, Premier League, English Football League and League Managers Association said that "based on early findings, which showed the majority of headers involve low forces, the initial focus of the guidance [for professional football] will be on headers that involve higher forces."
However, it adds that the recommended limit of 10 higher force headers in any training week "will be reviewed regularly as further research is undertaken to understand more regarding the impact of heading in football".
"I'd like to see the restrictions of heading as a whole, not just the high force heading," said Astle.
"What we don't want is for any player, regardless of whether they're elite level or children playing on a Saturday and Sunday, to be thinking that what they call the low force headers are OK, and there is no concern, because they are equally worrying."
In the professional game, the guidelines recommend that club staff monitor each player's heading practice and develop player profiles to ensure that training sessions reflect the type and quantity of headers each player can expect to face in a game.
At amateur level, players should be responsible for monitoring their own heading activity.
"I can't imagine a player saying 'boss, this will be my 11th [header]'," Astle added. "I just don't know how it's going to work. They'll have to put more detail into it and strengthen it for my concerns to go over that.
"Through the Jeff Astle Foundation, we do get emails from families of players with dementia who only played as amateurs, and I've always thought it's not just something that's unique to the professional game."
Peter McCabe, chief executive of brain injury association Headway, welcomed the guidance "after years of inaction" by the FA, but asked: "What would be the consequences for a player who tells his manager in training that he has already exceeded his quota of headers of the week?"
What else is being done?
Last November, 30 former professionals signed up to a study into the early signs of dementia.
The PFA also confirmed it is setting up a new taskforce to further examine the issue of brain injuries in football and would continue to fund research by Dr Willie Stewart, the neuropathologist who said that Jeff Astle was killed by chronic traumatic encephalopathy (CTE), aged 59 in 2002.
Then in February, the PFA and FA called for applications for further independent research into neurodegenerative disorders in former professional footballers.
Dawn Astle also called for greater education about the impact of heading in football and says that, ultimately, it will be banned from the game altogether.
"As more and more evidence comes to light, I don't think football will have any option," she said. "You can't put players at risk of something that can kill them later on in life.
"There needs to be a much bigger and better drive towards educating players, coaches and parents across all levels of the game. This message has to get through because players are dying. It's as simple as that."
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