Study finds even minor hits can cause long-term problems. 

A study of American football players has found that even seemingly minor hits to the head – ones that don’t cause concussion – can bring long-term problems.

They damage a brain area linked to chronic traumatic encephalopathy (CTE), a condition that leaves some sportspeople with thinking problems, mood disorders and even dementia.

A team led by Adnan Hirad, from the University of Rochester Medical Centre, US, put sensors in the helmets of 38 male football players to monitor the force of head impacts across a season of the notoriously high-contact sport.

The sensors were primed to measure two kinds of impact: linear movements, where the brain bounces forwards and backwards after a hit, and rotational movements, where it twists around on the central stalk known as the brainstem.

The players also got MRI brain scans before the season started and just after it finished.

When the results came in, the players had sustained a colossal 19,128 head hits, averaging more than 500 impacts each.

Nearly 60% of those happened during practice and 37% were during games. The typical force of linear hits was just over 25gs: astronauts lifting off into space experience 3gs, and race car drivers around 6gs.

Strikingly, however, those linear impacts were not the smoking gun in this study.

Read the full article in Cosmos magazine here