As scientists reveal more about the adverse effects of concussions in high-impact games like football and hockey, the public is becoming increasingly aware of the dangers of head injuries.

Those two games, however, are not the only ones that have been shown to cause damage.

Soccer is the most popular sport for Canadian children, with almost 42 percent playing regularly. Headers are a vital part of the game, and players able to put away a top-corner goal off a hurtling cross are in high demand.

Recent research from UBC, however, has shown that repetitive impacts of a soccer ball on a person’s head could cause damage to the nervous system. The scientists’ findings, published in the BMJ Open Sport and Exercise Medicine, have implications for the more than 270 million soccer players worldwide.

Along with his team of researchers, neuroscientist and study leader Paul van Donkelaar chose to measure participants’ levels of two nerve cell enriched proteins, named tau and light neurofilament (NF-L). The researchers chose these two compounds because previous studies have shown that when the brain is damaged through repeated trauma, tau and NF-L build up and tangle in its cells, causing symptoms including mental impairment, impulsive behaviour, memory loss, depression, and an altered personality.

The team evaluated the impact of 40 headers on a group of participants. Those numbers were then compared to a different day, when individuals did not contact the soccer ball with their head.

On the day that participants headed, their NF-L levels were higher than those when they rested. In addition, the higher NF-L levels correlated with a higher number of concussion-like symptoms such as headaches, dizziness and confusion. There was no difference in the tau levels between the groups.

“Soccer is unique in that playing the ball with the head is encouraged, yet players don’t wear protective headgear,” said van Donkelaar said. “These findings suggest that repetitive impacts in the form of soccer headers can cause damage to the nerve cells as measured by elevated NF-L levels and increased concussion-related symptoms.”

An increased NF-L level is also associated with chronic traumatic encephalopathy, or CTE—a condition that has received a large amount of media attention in the past few years. Thought to be caused by repeated blows to the head and concussions, the disease—which can be only be conclusively diagnosed after death—causes areas of the brain to waste away. On North American sports teams, soccer ranks third behind football and hockey for the rate of concussions.

“Sport-related concussion is becoming a major concern for athletes, parents, coaches and sport associations,” van Donkelaar said. “Finding ways to improve the safety of contact sports is one key approach to mitigating the risks.”

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