Liverpool Hope University research detailing how heading a football just 20 times could be enough to have a detrimental effect on brain function has been attracting national attention.
A study took a group of test subjects and analysed ‘cognitive function’ - including memory and mental ability - before and immediately after they headed a football twenty times.
And the results, published this week in the journal Science and Medicine in Football, showed how ‘working memory’ declined by as much as 20 per cent.
Worryingly, the vast majority of test subjects also displayed signs of concussion.
And the evidence has been discussed across the media, from The Guardian to the Telegraph and the Daily Mail.
Jake Ashton, a Postgraduate research student at Hope, said: “Our results are both surprising and concerning.
“We investigated the immediate effect heading a football has on cognitive function.
“Participants performed a series of cognitive function tests before and after a bout of 20 headers.
“They also performed a pitch-side screening for concussion, which showed that 80 per cent of the participants showed potential signs of concussion.
“With the cognitive tests, there was a significant reduction in verbal and spatial working memory.”
The study itself involved a group of 30 recreational male soccer players aged between 18 and 21 years old.
They were split into three groups - that undertook 20 consecutive headers with either a soft (8.8 psi) ball, hard ball (16.2 psi), or no ball at all.
Overall, when ‘Saccadic eye speed’ was measured - ie, how quickly you can locate and identify visual targets - function decreased by around 10 per cent.
Spatial span - the recall of objects in space within a particular sequence - reduced by an average of 15 per cent.
Meanwhile ‘digit span’ - the recall of certain numbers within a particular sequence - tailed-off by 20 per cent in the group heading the hard football.
There are also ramifications when it comes to concussion.
The ‘Saccadic eye speed test’ is adopted by many experts in North American sports as an indicator of concussion.
The time needed to complete the test increased by three seconds when compared to baseline, it’s considered a possible concussion and athletes are removed from competition.
As part of the research, participants indicated a four second gain following headers, while also being more error prone.
Jake - who also acted as a guest on BBC Radio Merseyside this week (Link here, fast forward to 1 hour and 36 minutes for the full interview) adds: “Ten of the participants headed balls with a PSI of around 8, while the other 10 headed balls with a PSI of around 16 - pressures at either end of FA guidelines.
“The group with the higher-pressure ball showed greater declines in working memory than the other group.
“And overall both groups showed significant reductions in verbal and spacial working memory.
“Our research doesn’t look at the repercussions of heading a football over a number of years.
“While more research is needed, there may also be a need to put measures in place to limit heading during football training sessions, in all ages.
“It may also be advantageous to use sponge balls during children’s training sessions, so they can practice the technique without having the repercussions of heading a heavier ball.
“The impacts of using a harder ball should also not be ignored.”
Jake also suggests that referees at grassroots levels measure the ball pressure before match kick offs.
There’s a growing clamour for the links between dementia and football to be further investigated following the recent dementia diagnosis of World Cup winner Sir Bobby Charlton.
England manager Gareth Southgate has also expressed his own concerns in recent days.
He told the BBC: “At my age, having headed a lot of footballs, I do have concerns.
"In terms of the link, there is research going on. That's a little bit inconclusive at the moment, which is a bit frustrating for everybody because we'd love to have a clear solution.
"Of course it's a concern for everybody and we have to keep supporting that research. Unfortunately we don't have all the answers we'd like at the moment."
The initial move to limit heading in training came following a separate report, published in October last year by the University of Glasgow, which found links between former professional footballers and brain disease.
The study suggested players could be three and a half times more likely to die of dementia.
At the time Dr Willie Stewart, the consultant neuropathologist who led the University of Glasgow study, said: “A lot more research is needed to understand the factors contributing to increased risk of neurodegenerative disease in footballers.
“Meanwhile it is sensible to act to reduce exposure to the only recognised risk factor so far."