Author(s): RUF, L., HÄRTEL, S., ALTMANN, S., Institution: TSG RESEARCHLAB, Country: GERMANY, Abstract-ID: 836

INTRODUCTION:
This study investigated distances covered during linear sprints to reach absolute (20.0 km.h-1, 25.0 km.h-1) and relative sprinting thresholds (70%, 80%, 90% of Maximal Sprinting Speed (MSS)) and MSS itself in highly trained male U12 to U17 youth soccer players. We examined through mediation analysis whether age-related effects on these distances operate primarily through increases in MSS or involve additional developmental factors.
METHODS:
We collected data from 110 male youth soccer players using a cross-sectional design. Players performed two 40m linear sprints with the velocity continuously measured with a radar gun. Raw velocity-time data were smoothed using cubic splines. Generalised additive models examined relationships between MSS (range: 23.5 km.h-1 to 34.1 km.h-1) and distances to sprinting thresholds, and between chronological age and distances to sprinting thresholds. Mediation analysis quantified the extent to which age effects on distances were transmitted through MSS (indirect effects) versus age-independent pathways (direct effects) for absolute sprinting thresholds.
RESULTS:
With increasing MSS, distances to 20.0 km.h-1 decreased from 7.0 m to 3.5 m, to 25.0 km.h-1 from 23.7 m to 7.0 m, to 70% MSS increased from 3.5 m to 5.9 m, to 80% MSS from 5.8 m to 9.4 m, to 90% MSS from 9.9 m to 15.9 m, and to MSS from 24.0 m to 36.3 m. With increasing age, corresponding values were 6.4 m to 3.8 m, 19.7 m to 7.7 m, 3.9 m to 5.3 m, 6.3 m to 8.4 m, 10.7 m to 14.3 m, and 26.2 m to 34.4 m. Mediation analysis revealed that age effects on absolute sprinting thresholds operated primarily through MSS, while distances to MSS involved both MSS-dependent and MSS-independent pathways.
CONCLUSION:
We investigated distances to absolute (20.0 km.h-1, 25.0 km.h-1) and relative sprinting thresholds (70%, 80%, 90% of MSS) and MSS itself in U12 to U17 youth soccer players. Distances to absolute sprinting thresholds decreased with increasing MSS and age, while distances to relative sprinting thresholds and MSS increased. Mediation analysis revealed that age effects on distances to 20.0 km.h-1 and 25.0 km.h-1 operated almost entirely through increases in MSS, whereas distance to MSS was influenced by both MSS increases and MSS-independent developmental factors. Practitioners can use these age- and MSS-specific distance benchmarks to individualise sprint prescription in team sessions, individual training, and rehabilitation contexts.