Concussions make up roughly 22% of all soccer related injuries. As such, concussion prevention is a main focus, with efforts being made to help recognize how and why concussions occur, and if aspects of the sport can be changed to decrease the prevalence of head injuries. Lately, attention has been focused on whether or not heading in soccer can lead to concussion directly or if the cumulative effects of sub-concussive impacts, as seen with multiple headers in one game, can result in brain injury.
Research has shown that the majority of concussions in soccer occur as a result of player to player contact or player to ground contact, with roughly 30% of concussions occurring during heading. However, the majority that occurred during heading (60-78%) were not related to ball contact; they were related to contact with another player. Furthermore, studies have looked at the acceleration forces (linear and rotational) required to sustain a concussion, and soccer headers produce a mean acceleration well below the concussion threshold.
If heading the ball generally doesn’t produce enough force to cause a direct concussion, can the cumulative effects of repetitive heading lead to brain injury? A review of 7 high quality studies, all examining the effects of heading on cognitive functioning immediately following practices or games, found no significant effects between heading and neurocognitive functioning. However, research that has examined long term effects of soccer participation and heading is less understood. Some studies have shown that high level soccer players who have played for a number of years have cognitive deficits related to attention, memory, visual processing and concentration when compared to non-soccer athletes. However, most of these studies examining long term effects of playing soccer and heading on brain injury are not well done. For example, most studies were completed retrospectively and relied on the athletes memory of their heading and concussion history. There was usually no history taken into account for mental health issues, drug abuse, stress, education, pre-soccer baseline testing, or other factors that could have caused the cognitive deficits. As such, current research regarding the long term effects of heading in soccer is inconclusive.
Take home message:
- There is no evidence that heading in soccer causes permanent brain injury or neurocognitive dysfunction.
- There is limited evidence that heading causes concussion.
- No definitive research exists to show long term effects of heading on cognitive impairment.
- In order to decrease the prevalence of concussion in soccer, coaches and trainers should focus on teaching safe and proper heading techniques, with a reduction of athlete-to-athlete contact.
Maher et al., Concussion and heading in soccer: A review of the evidence of incidence, mechanisms, biomarkers and neurocognitive outcomes. (2014). Brain Injury; 28(3): 271-285.