Author(s): BENYAHIA, L., THOMAS, K., HICKS, K., HENDRY, D., Institution: NORTHUMBRIA UNIVERSITY, Country: UNITED KINGDOM, Abstract-ID: 2114

INTRODUCTION:
Current FA guidelines for girls’ talent pathways in England advocate for girls to play football in boys leagues to enhance their development, though benefits have not yet been quantified. This study examined technical and physical differences between mixed (i.e. vs boys) and same-sex (i.e. vs girls) competition in U12 and U14 girl's academy players.

METHODS:
Players from two girl’s professional football Academies (n = 88, age: 11.4 and 13.4 years) participated in the study across the 2024/25-2025/26 seasons. Players wore a foot-mounted inertial measurement unit (Playermaker) that captured physical (total distance, high intensity distance (U12:>3m/s, U14:>4 m/s), sprint distance (U12:>5m/s, U14:>5.5 m/s), accelerations/decelerations, top speed) and technical (touches, releases, time on the ball, one touch actions) metrics. U14 matches were 80 minutes, 11v11 format, and 60 minutes of 9v9 format in U12 matches.

281 U14 observations (51 players: 90 vs boys, 191 vs girls) and 322 U12 observations (37 players: 198 vs boys, 124 vs girls) were analysed. Separate linear mixed-effects models were used to investigate the impact of opposition gender on physical and technical performance, with player as a random effect and participation time as a covariate. The analyses were conducted in R using the nlme package, with maximum likelihood for model comparisons and restricted maximum likelihood for final parameter estimates.

RESULTS:
After controlling for participation time, U14’s covered significantly greater total distance (5384m vs 4982m, p=0.025), high intensity distance (704m vs 570m, p<0.001), and sprint distance (70m vs 46m, p<0.001) vs girls than vs boys. However, they had significantly fewer touches on the ball (62 vs 83, p<0.001), less time on the ball (31s vs 46s, p<0.001), and fewer releases (23 vs 29, p<0.001) vs girls than vs boys. There were no significant effects on accelerations/decelerations, top speed or one touch actions (p >0.05).

U12’s had significantly more touches in games vs girls than vs boys (71 vs 62, p<0.001). However vs girls, players covered significantly less high intensity distance (1038m vs 1109m, p=0.031) and sprint distance (49m vs 62m, p=0.0015) than games vs boys. There were no significant effects on distance covered, top speed, accelerations/decelerations, total time on the ball, one touch actions, or releases (p >0.05).

CONCLUSION:
Findings suggest age specific differences when comparing same sex and mixed sex competition. The implications for practice and research are discussed. U14 players may develop their physical abilities when playing against girls and enhance their technical abilities playing against boys. Playing against boys at U12 may enhance the ability to perform longer at higher intensities though most metrics showed no differences. However, opposition skill level was not considered, and should be investigated to confirm if effects are attributed to gender or skill level.