Abstract
This study uses data from the 2019 Fédération Internationale de Football Association Women’s World Cup to determine the incidence rate and subsequent medical assessment of head collision events.
The International Conference on Concussion in Sport protocols, which state that all athletes with suspected concussion must receive medical assessment, have been supported by elite soccer organizations.1 However, a majority of male soccer players do not receive medical assessment after head collision events (HCEs).2,3,4 To our knowledge no research has analyzed HCEs in elite women’s soccer. The purpose of this study was to determine the incidence rate and subsequent medical assessment of HCEs in the 2019 Fédération Internationale de Football Association (FIFA) Women’s World Cup and to compare these with rates from 3 elite men’s tournaments.
Methods
The 52 matches of the 2019 FIFA Women’s World Cup were independently reviewed by 3 trained observers who recorded data on frequency and medical assessment of HCEs, time stopped for assessment, and visible concussion signs. Data were collected using the same standardized form as in prior HCE analyses.2,3,4 The Cohen κ among reviewers was 0.88. Head collision events were defined as any incident in which a player was unable to resume play within 5 seconds of direct head contact. Medical assessment was any assessment on the field or sideline conducted by health care team personnel. Time stopped for assessment was the duration between the player receiving assessment and returning to the match. Players involved in HCEs were observed for the following visible signs of concussion: clutching of head, slowness getting up, disorientation, disequilibrium, loss of consciousness, and seizures.
Data from 3 elite men’s tournaments were combined for the comparative analysis.2,3,4 All 4 studies were conducted in the same way using the same definitions. The Mann-Whitney U test was used for comparison of median time stopped for assessment. Categorical variables were compared using the χ2 test or Fisher exact test as appropriate. Incidence comparisons were estimated by quasi-Poisson generalized linear models. Two-sided statistical significance was set at P < .05. R version 3.6.0 (R Core Team 2019) was used for statistical analysis. The research ethics board at St Michael’s Hospital waived the need for approval.
Results
A total of 69 HCEs were identified during the women’s tournament (1.33 per match; 39.5 per 1000 athlete-hours of exposure) and 237 HCEs were identified in the 3 men’s tournaments (1.32 per match; 39.0 per 1000 athlete-hours of exposure) (incidence rate ratio, 0.99 [95% CI, 0.76-1.28]; P = .93) (Table). Of the 69 women involved in HCEs, 53.6% received medical assessment, which was significantly greater than the percentage of men who received medical assessment (33.8%) (P = .003). Five men and 4 women were removed from the match after assessment (P = .46). All men and women who did not receive medical assessment immediately returned to play. The median time stopped for assessment was 70 seconds (range, 10-330) for women and 49.5 seconds (range, 15-280) for men (P = .04). The majority of female (84.1%) and male (88.6%) athletes showed 2 or more signs of concussion after an HCE.
Table. Head Collision Event (HCE) Outcomes and Assessment in Elite Men’s and Women’s Soccer Tournaments.
| Outcome | Men (n = 237) | Women (n = 69) | P Value |
|---|---|---|---|
| HCEs per 1000 athlete-hours of exposure (95% CI) | 39.0 (34.4-44.1) | 39.5 (31.4-49.6) | .93 |
| Signs of concussion, No. (%) | |||
| 0 | 5 (2.1) | 0 | .19 |
| 1 | 22 (9.3) | 11 (15.9) | |
| 2 | 153 (64.6) | 48 (69.6) | |
| 3 | 53 (22.4) | 9 (13.0) | |
| ≥4 | 4 (1.7) | 1 (1.4) | |
| ≥2 | 210 (88.6) | 58 (84.1) | .31 |
| Medically assessed, No. (%) | 80 (33.8) | 37 (53.6) | .003 |
| Removed from game after HCE assessment, No. (%) | 5 (6.3) | 4 (10.8) | .46 |
| Time stopped for assessment, median (range), s | 49.5 (15-280) | 70 (10-330) | .04 |
Discussion
Previous research suggests that female athletes may have higher rates of sport-related concussion than men,5 yet this analysis showed that elite female and male soccer players had rates of HCEs that were not significantly different. Women were more frequently medically assessed than men, although there were no significant differences in the proportions removed from play. Reasons for the similar prevalence of HCEs but different rates of concussion and the higher rate of assessment in women’s soccer are unknown.
The median times for assessment of both sexes were far short of the minimum 10 minutes required to perform a concussion assessment.6 Changes to improve adherence to the international consensus concussion protocols are needed and could include increasing the role of the video assistant referees in calls for medical assessment, employing independent medical assessors, and allowing temporary substitutions to provide sufficient time for medical assessments. Limitations of this study were that actual independent medical diagnosis of concussions was not available to the study team and off-camera HCEs may have been missed by reviewers.
Section Editor: Jody W. Zylke, MD, Deputy Editor.
References
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