Author(s): STEFANSDOTTIR, R., JOHANNSSON, E., ROGNVALDSDOTTIR, V., Institution: UNIVERSITY OF ICELAND, Country: ICELAND, Abstract-ID: 158

Introduction
Participation in organized youth sport provides important benefits for physical health and development. Although girls’ participation in football has increased in recent years, research on maturation and performance in youth sport remains largely focused on boys. One factor that may influence development and selection in youth sport is the Relative Age Effect (RAE), which has been widely documented in boys’ sports but appears less consistent and less well studied among girls.

Methods
The aim of this study was to examine the presence of the RAE among 12-year-old Icelandic female football players and to explore its association with physical performance and team placement. A total of 150 players (born in 2012) from 10 clubs in the capital region participated. Data were collected during regular team training sessions in spring 2024 following ethical approval. Players were grouped by birth quarter (Q1–Q4) and completed standardized physical performance tests, including the Intermittent Recovery Test Level 1 (IR1), countermovement jump (CMJ), 40 m sprint, and Illinois Agility Test with ball control. Team placement was categorized into three ranks based on evaluations provided by the coaches.

Results
The sample showed that the largest proportion of players were born in Q1 (32.4%), followed by Q3 (27.6%) and Q4 (23.4%), while Q2 had the lowest proportion (16.6%). No differences were observed between birth quarters in distance covered in the IR1 test, jump height in the CMJ test, 40 m sprint performance, or performance in the Illinois Agility Test with ball control. Team placement was similarly distributed across birth quarters, with no apparent differences in representation across team ranks.

Discussion
In summary, the observed birth-quarter distribution was not reflected in physical performance measures or team placement in this cohort. These findings suggest that relative age differences may have limited influence on physical performance and selection outcomes in 12-year-old Icelandic female football players.