Explainer: Soccer Playing and Forces

One of the risks of brain injury in soccer comes from the forces applied during an integral part of the game – heading the ball.

This resource explains forces for Year 7 Physics students via the medium of soccer and provides a set of review questions that can be used to assess student understanding.

Contact sports around the world are struggling with the problem of concussion of players – how can we protect players to prevent lifelong problems from something that is inherently meant to be fun?

However, while all the attention has been on contact to their head during tackles or accidental head-to-head contact, researchers have identified an overlooked source of brain injuries in soccer – and it’s an integral part of the game.

They have found that heading the ball by soccer players could be doing damage.

Cognitive function reduced in soccer players

The researchers have previously found that heading the ball could be a source of some concussion symptoms. However, they’ve now found that, in addition to that, it could alter cognitive function as well, at least temporarily.

In fact, the players who head the ball the most have the worst performance on psychomotor speed and attention tasks, which are areas of functioning known to be affected by brain injury.

Frequent headers also had poorer performance on a working memory task, although the association was barely statistically significant.

Impacts to the head between players, the ground, or goal posts did not seem to have any effect on any part of cognitive performance.

The results were found after surveying over 300 amateur soccer players about their playing style and use of their head, as well as impacts to their head. The players were then tested to measure their cognitive performance.

“Unintentional head impacts are generally considered the most common cause of diagnosed concussions in soccer, so it’s understandable that current prevention efforts aim at minimizing those collisions,” said Michael Lipton, who led the research at the Albert Einstein College of Medicine.

“But intentional head impacts – that is, soccer ball heading – are not benign.”

Overall, the players headed the ball on average 45 times over a two week period, and around 100 players suffered an unintentional head impact, suggesting the repeated smaller hits from heading the ball may add up.

What can we learn from the study?

However, the study was only short term and involved a relatively small number of players. What it doesn’t answer is what impact this might have to the player in the medium to long term, or whether the brain recovers during the off season.

Similarly, as the study is not longitudinal, it doesn’t present evidence as to whether these players’ previously had higher cognitive function that has declined due to heading-induced damage, nor whether their cognitive abilities continue to decline as the season goes on.

To address some of these shortcomings the researchers are now interested in following players for a longer period to find if the damage is permanent, and has any cumulative, serious effects as life goes on.

“We’re concerned that subtle, even transient reductions in neuropsychological function from heading could translate to microstructural changes in the brain that then lead to persistently impaired function. We need a much longer-term follow-up study of more soccer players to fully address this question,” said Dr Lipton.

The research has been published in Frontiers in Neurology.