Circumstances of head impacts in Hong Kong men’s collegiate soccer players

This observational study investigated the circumstances of head impacts in men’s collegiate soccer matches in Hong Kong. Videos of twelve matches organized by the University Sports Federation of Hong Kong, China (USFHK) were collected and analyzed. Two trained raters used a structured questionnaire to classify situational factors preceding and at the instant of head impacts. Generalized linear models were used to compare response categories for the proportion of players experiencing at least one head impact and the number of head impacts per player. A total of 844 head impacts were examined, with an average of 3.0 head impacts per player per match. Most head impacts involved intentional heading (97.6%) and head-to-ball contact (98.0%). Players experienced head impacts predominantly in defensive and offensive outfields (except for corner areas), accounting for 49.5% and 25.4% of all events, respectively. A notable proportion of head impacts occurred from long passes in the air (43.5%). Players headed frequently with the top of their heads (48.3%), which is a suboptimal site. Our result indicated that heading is highly purposeful among collegiate soccer players primarily because over 90% of head impacts were intentional and head-to-ball contact. However, forceful contesting of aerial balls in the outfields, heading from long-distance passes and using a suboptimal impact site during heading can potentially lead to head injuries. Coaches should prioritize neck and core strengthening, focusing on executing the correct heading technique by training contacting the ball with the forehead and discouraging heading fast-rising balls.