Author(s): DE STE CROIX, M., AYALA, F., MOYA ANTON, R., HUGHES, J., HODUN, M., Institution: UNIVERSITY OF GLOUCESTERSHIRE, Country: UNITED KINGDOM, Abstract-ID: 514

INTRODUCTION:
There are several studies that have explored match demands in women’s football [1], however most of these studies use absolute metrics which does not provide information regarding the degrees of variability in these metrics. Existing literature has not established any framework for interpreting practically meaningful match‑to‑match changes in youth female football. Match to match variability in physical demand could be due to a number of factors including, tactical reasons as well as external factors such as the weather. The purpose of this study was to employ multiple statistical approaches to decompose and individualise the variability of GPS-derived match performance demands in female youth football.
METHODS:
Thirty-six youth female footballers (15.0 ± 0.6y, 161.9 ± 5.3 cm, 56.2 ± 6.5 kg, maturational offset 2.3 ± 0.6 y) contributed 93 full-match (80 min) observations across 20 competitive matches. Players wore 15 Hz GPs units (GPSports, Canberra, Australia). A wide range of match variables were determined, and the running and sprinting thresholds were set according to those determined by Bradley and Vescovi [2]. Three complementary approaches were used: Limits of Agreement (LoA) to characterise typical match-to-match variation, Smallest Worthwhile Change (SWC) (0.2×between-player SD) to define a minimal practically important effect, and practically significant change thresholds (e.g., LoA90/α-based thresholds). Minimum effects testing (MET) was used to estimate the probability that an observed change exceeded the SWC given the estimated variability. All statistical analyses were conducted in RStudio (version 2024.09.0+R-4.3.2; Posit Software, Boston, MA).
RESULTS:
Variance partitioning showed negligible positional effects (0.0–2.6%) and small-to-moderate team effects (0.0–18.5%), with most variance explained by between-player (7.2–84.0%) and within-player match-to-match components (4.5–48.1%). Practical change thresholds were substantial (α=0.05: ±1909 m total distance, ±580 m HSR, ±256 m sprint distance), while MET indicated modest probabilities for typical changes (pMET ≈0.45–0.51); patterns were broadly similar across halves, with greater first-half dispersion for some high-intensity metrics.
CONCLUSION:
In youth female football, match demands vary primarily due to player-specific and within-player match-to-match factors, with minimal positional effects. The proposed threshold-based (LoA/SWC) and probabilistic (MET) outputs provide an applied framework to distinguish normal fluctuations from practically meaningful changes and may support post-match decision-making when integrated with internal-load and recovery indicators. Further longitudinal monitoring and integration with well-being and training load, may help understand the recovery and readiness characteristics in female youth football.
[1] Harkness-Armstrong et al, 2021/ [2] Bradley & Vescovi, 2015