Abstract:Purpose: To examine the relationship between oxygen uptake kinetics (VO2 kinetics) and physical measures associated with soccer match-play, within a group of highly trained youth soccer players. Methods: Seventeen highly trained youth soccer players (age: 13.3 ± 0.4 yr, selfassessed Tanner Stage: 3 ± 1) volunteered for the study. Players initially completed an incremental treadmill protocol to exhaustion, to establish gaseous exchange threshold (GET) and VO2max (59.1 ± 5.4 mL.kg-1.min-1). On subsequent visits players completed a step transition protocol from, rest-moderate intensity exercise, followed by an immediate transition from moderate-severe intensity exercise (moderate: 95%GET, severe: 60%∆), during which VO2 kinetics were determined. Physical soccer-based performance was assessed using a maximal Yo-Yo Intermittent Recovery test level 1 (Yo-Yo IR1) and via GPS derived measures of physical soccer performance during soccer match-play, 3 2 x 20min, 11 v 11 matches, to gain measures of physical performance during soccer match-play. Results: Partial correlations revealed significant inverse relationships between the unloaded to moderate transition time constant (tau) and: Yo-Yo IR1 performance (r = -0.58, P = 0.02) and GPS variables (Total distance (TD): r = -0.64, P = 0.007, High speed running (HSR): r = -0.64, P = 0.008, High speed running efforts (HSReff): r = -0.66, P = 0.005). Conclusion: Measures of VO2 kinetics are related to physical measures associated with soccer match-play and could potentially be used to distinguish between those of superior physical performance, within a group of highly-trained youth soccer players.