Heading in football has been under the spotlight for more than 20 years. The scrutiny is born of fear and confusion.
There is fear that the act itself could have long-term effects on the brains of those who do it most, and confusion over why it happens and how great the risks really are.
Science has begun to provide some answers, but there is still a long way to go before fully understanding the impact of something that has been part of the game since its very beginning.
The research to date has been worrying enough to force some rule changes by governing bodies.
For many people, the threat still feels abstract – worthy of attention only when another of the game’s greats is diagnosed with dementia or Alzheimer’s.
Some take comfort from the belief that football has changed, that coaching is different, the balls are lighter and the modern game is played more on the ground.
That very much depends on which league you are watching.
Scotland’s High Heading Stats Compared to Europe
New data shows the Scottish Premiership records significantly more headers per match than most of Europe’s top leagues.
BBC Scotland looked at figures from the start of season 2021 until now, covering aerial duels and headed clearances, in the top leagues of Scotland, England, Italy, France, Germany and Spain.
In the Premiership, players challenge for the ball in the air, on average, 42.5 times per match – a 71% increase on France’s Ligue 1, at 28.5 times per match.
Fans watching the Premier League in England can expect to see 28.7 aerial duels per match – nearly 50% fewer than Scotland.
It is a similar picture in Germany, Spain and Italy, who all challenge for the ball in the air significantly less than in Scotland.
With headed clearances, France provides the starkest comparison.
In Ligue 1, you will find an average of 16.8 headed clearances per match – that is almost 50% fewer than Scotland’s 24.7 per match.
The EPL (21.3), Bundesliga (21.2), Serie A (18.2) and La Liga (19.4) all clear the ball with the head less than in Scotland.
Further data also shows the trend continuing with comparable leagues.
There are almost 60% fewer aerial duels in the Czech First League.
The top leagues in Denmark, Sweden and Norway also record over 40% fewer aerial duels than the Premiership.
There are also fewer headed clearances in Denmark, Norway, Sweden, Czech Republic and Austria.
Looking at the combined metrics of Scotland compared to 10 top leagues around the continent, there are more than 35% more heading actions in Scotland.
The Safety Implications of Heading in Football
The figures may not come as a shock to those who watch Scottish football on a regular basis, but they do throw up questions about what it means for the discussion around safety.
Since the death of former England centre-forward Jeff Astle from dementia in 2002, scientists have increasingly linked repeated head impacts to chronic traumatic encephalopathy (CTE), which can also lead to neurodegenerative disease.
In January, a coroner investigated the death of former England centre-forward Jeff Astle from dementia.