Soccer Heading: Review on Evidences on The Prevalence, Mechanisms and Biomarkers ‎of Head Injuries

Purpose:Football (Soccer) is associated with an inherent risk of head injuries and is also unique in "heading" skill. Heading can activate biomarkers of brain damage. The present study provides a comprehensive review of researches on the prevalence of head injuries and the effectiveness of biochemical markers in performing this skill.Methods:Scientific libraries were searched for studies published between 2000 and 2021. Search terms included ‘Head Injuries’, ‘Brain Injuries’, ‘Epidemiology’ and ‘Soccer’. Studies that contained data on heading, biomarkers of brain injuries, injury incidence rate and mechanisms were included. Non-English and non-Persian studies, contained data on non-soccer related injury, or conference abstracts were excluded. From 243 articles related to the subject, 45 articles had inclusion criteria.Results:Head injuries rate in premier leagues varies (range of change 0.3% to 16.8%, or 0.12 to 1 per 1000 hours) and is lower compared to reports of semi-professional leagues (0.3% vs 22%). Heading is not common head injury mechanisms in premier leagues. The most common markers used to assess brain damage are S100B (8 studies) and NF-L (6 studies). Tau (3 studies), NSE (2 studies), albumin (1 study) and brain growth factors (1 study) were also used to evaluate the effectiveness of heading skills. In total, 9 studies reported changes in levels and 11 studies of no changes in markers levels following heading at different ages in both women and men.Conclusion:Exposure to repeated subconcussive and high speed impacts as the form of soccer heading may lead to brain damage that can be detected using biochemical markers. The results of the present study show that heading in football should not be overlooked as a potential mechanism of brain injury. Of course, more research is needed to clarify the possibility of such a relationship.