Position-specific pre-match load and match-day running performance in elite youth footballers: a de-identified GPS dataset

De-identified dataset and reproduction code for a study of position-specific pre-match load–performance relationships in elite youth footballers. The dataset comprises 386 player-match observations from 19 male U17 academy players of a Chinese Super League club, monitored across 41 official matches during the 2024 competitive season (March–November). Variables include per-90-minute match-day high-intensity running distance (HID), acceleration/deceleration counts (Acc/Dec), seven-day cumulative pre-match load metrics, and match-context covariates (opponent strength, venue, score difference, ambient conditions, match importance, tactical formation). Player names, opposing-team names and exact calendar dates have been replaced with anonymous codes to protect player and club privacy. The accompanying R script reproduces the descriptive statistics, the position-stratified mixed-effects quadratic regression models, and the cluster-bootstrap 95% confidence interval for the wide-defender HID vertex. Tested under R 4.5.2, lme4, and lmerTest. Files included: PMLY_dataset_deidentified_v2.xlsx (analytic dataset, 386 rows × 31 columns) and reproduce_paper.R (R reproduction script).