Global Versus Individualized Speed Thresholds for High-Intensity Running and Sprint Distance in Youth Football Players: The Role of Peak Height Velocity

OBJECTIVES This study examined whether disagreement between global and individualized speed thresholds in youth football players varies according to biological maturity status. Specifically, high-speed running (HSR) distance and sprint distance derived from the two threshold methods were compared across peak height velocity (PHV) stages.METHODS A total of 105 youth football players were included and classified as pre-PHV (n = 34), during-PHV (n = 40), or post-PHV (n = 31). External load data were collected over 54 sessions, comprising 42 training sessions and 12 match sessions, yielding 6,401 observations. HSR and sprint distance were calculated using both global and individualized thresholds. Paired t-tests were used to compare the two threshold methods, Bland-Altman analyses were performed to assess agreement, and linear mixed-effects models were applied to examine the effects of threshold type, PHV group, session type, position, and threshold-by-PHV interactions. Separate mixed models were also performed for HSR gap and sprint gap.RESULTS Overall, global thresholds produced significantly higher values than individualized thresholds for both HSR distance (289.4 ± 241.8 vs. 261.1 ± 203.7 m; mean difference = 28.3 m, 95% CI = 18.9 to 37.7, <i>p</i> < 0.001) and sprint distance (42.6 ± 64.1 vs. 34.2 ± 49.0 m; mean difference = 8.4 m, 95% CI = 4.8 to 12.0, <i>p</i> < 0.001). Significant threshold-by-PHV interactions were observed for both variables, indicating that the magnitude and direction of disagreement differed according to maturity stage. Gap analyses further showed that the discrepancy between methods increased from pre- to post-PHV, with PHV group emerging as the main determinant of both HSR gap and sprint gap. Bland-Altman analyses demonstrated systematic bias, wide limits of agreement, and significant proportional bias for both HSR and sprint distance.CONCLUSIONS Global and individualized speed thresholds should not be considered interchangeable in youth football players. Their disagreement is maturity-dependent, suggesting that biological maturity should be considered when interpreting high-intensity external load data in developmental football populations.