Video analysis of head impacts in top-level female football players: a cohort study

This study aimed at exploring the exposure of head impacts, i.e. headers and non-headers, in top-level female football players. The study included all teams (<i>n</i> = 10) and players (<i>n</i> = 238) in the Norwegian Women's Premier League during the 2023 season. Video analysis was used to register headers and non-headers in the 135 matches of the season. Potential head injuries were compared between video signs and medical reports. The header and non-header incidences were estimated per 90 match minutes with 95% confidence intervals (CI). We observed 9364 headers and 233 non-headers in 135 matches. Nine non-headers resulted in a head injury (all concussions), players' time loss ranging from 5 to 87 days. The highest number of headers performed by a single player in a match was 22. The total number of headers performed during a match varied between 34 and 125. Defenders had an estimated 4.2 (CI = 3.9-4.3), midfielders 2.9 (CI = 2.7-3.0), and forwards 2.6 (CI = 2.5-3.1) headers per match. There was a positive correlation between heading frequency and age. Forwards were the players most exposed to non-headers, with an estimated 0.09 per match. Most non-headers were caused by unintentional head-to-ball contact. We found that defenders had the highest header frequency. Header frequencies varied substantially between players and from match to match. Forwards had the highest risk of non-headers. Nine non-headers resulted in head injuries.