Heading a football can damage brain by causing it to 'twist'
Heading a football can cause the brain to 'twist' and result in serious brain damage.
New research has revealed that side impacts to the head - experienced in football and boxing - can be as dangerous as frontal impacts.
This is because side impact often results in more intense multi-directional pressure being placed on the brain.
The pressure and strain can cause the brain to contort or twist and increases the likelihood of damaging tears occurring.
A research team from NUI Galway and UCD have spent months examining the effects these rotational accelerations or twists have on pig's brains.
Much previous research has focused on the effects of linear accelerations or frontal impacts.
These often happen in collisions such as car accidents and in American football.
Rotational accelerations have not been explored as extensively, but can cause just as much damage.
The twist experienced during impact can impair neurons and lead to concussion, brain injury and even permanent damage.
The danger of repetitive head injuries is a serious concern for professional sports people.
The new research is published this week in the international scientific journal Soft Matter.
Former Republic of Ireland striker Kevin Doyle had to retire from the game due to chronic concussion problems.
He spoke of being knocked unconscious when he was struck by a ball kicked by former England international Ashley Cole.
"As I turned, he hit the ball a few yards from me, right on the back corner of my head and I instantly zonked out," he said.
"Not knocked out, just gone, concussed. It was worse than I thought. My head just flopped and went 'bang, bang'."