Sex differences in association football: a scoping review

Despite some reviews examining sex differences in football within specific themes, a comprehensive, integrated overview of sex differences in football is lacking. This scoping review aimed to: (1) synthesize existing evidence regarding sex differences in elite football players; (2) identify research gaps to provide direction for future studies.

The protocol adhered to the PRISMA Extension for Scoping Reviews guidelines. The searches were conducted on October 17, 2024, in Scopus, PubMed, ScienceDirect, and Web of Science (Core Collection). The risk of bias was assessed using the Revised Risk of Bias Assessment Tool for Nonrandomized Studies of Interventions (RoBANS 2). A narrative synthesis was performed to summarize the main findings.

A total of 80 studies met the eligibility criteria and were included in the review, encompassing 4,896 players (2,226 female, 2,670 male) and 234 matches (99 female, 135 male). Seventy-two studies (90%) did not report female participants' menstrual cycles or contraceptive medication use. Only six studies exclusively used "sex"-related terminology, with not a single study using "gender"-related terminology alone. Seventy-four studies (93%) presented various degrees of mixed usage of the terms "sex" and "gender". All included studies were categorized into eight themes according to their research focus: Anthropometrics, Muscle and Joint Movements, Physiological Response, Physical Performance, Technical Performance, Match Performance, Psychological and Behavioral Performance, and Nutrition/Recovery/Sleep.

Perhaps due to a combination of innate biological factors and acquired dietary habits, female players, who typically have a higher body fat percentage and lower lean body mass, exhibit performance gaps compared to male players in terms of speed, strength, and endurance. These differences further affect their technical skills and match performance. However, while these absolute differences exist, they often diminish or even disappear when data are standardized against certain anthropometric or physiological metrics. This underscores the importance of developing individualized analytical methods and evaluation criteria tailored to female players. Future studies should carefully define sex-specific inclusion/exclusion criteria and select appropriate sex and gender terminology to minimize bias and enhance study quality.