Author: Ludwig Ruf et al.
Journal: International Journal of Sport Science and Coaching (2026)

A Long-Term Study of Sprint Speed Development (U12–U19)

It is a common belief in soccer academies that “speed is a gift you’re born with.” We often assume that the fastest U12 player will inevitably be the fastest U19 player. However, this 8-year longitudinal study by Ruf et al. (2026) challenges that paradigm, providing evidence that relative speed is more fluid during adolescence than we might think.

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The Big Picture: Can “Slow” Players Catch Up?

The study tracked 475 elite academy players over eight years to see how their Maximal Sprinting Speed (MSS) evolved.

Key Findings:

• Absolute Speed Always Improves: As expected, players get faster as they age, with the most significant “speed burst” occurring between U14 and U16, coinciding with peak height velocity (the growth spurt).
• Stability is Only Moderate: While there is some consistency, the long-term stability of a player’s speed ranking is only moderate (ICC = 0.65).
• The “Speed Flip”: Only 34% of players stayed in the same speed category across consecutive years. Remarkably, 41% actually dropped into a slower performance group relative to their peers.

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Performance Thresholds: Where Does Your Team Stand?

Coaches can use these average Maximal Sprinting Speed (km/h) benchmarks (based on the 20–30m interval of a 30m sprint) to categorize their players:

Age Group	Fastest (Top 10%)	Average (50th Percentile)	Slowest (Bottom 10%)
U12	>29.5 km/h	approx 25.3 km/h	<23.9 km/h
U14	>33.3 km/h	approx 27.7 km/h	<26.0 km/h
U16	>35.2 km/h	approx 30.7 km/h	<28.8 km/h
U19	>34.4 km/h	approx 32.0 km/h	<30.7 km/h
(Note: Data indicates U16s often show higher peak speeds than U19s in this specific academy cohort, likely due to squad turnover and maturation timing.)

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The “Fast vs. Slow” Dynamics

The study revealed a fascinating trend regarding how players move between speed groups:

1. Fast Players are at Risk: Players in the “Fastest” and “Fast” groups were more likely to move down (56%) than stay at the top. This is often because early-maturing players are fast early on but “plateau” while their peers catch up.
2. Slow Players Can Rise: Among the “Slowest” players, 46% moved up to a faster group.
3. The Rarity of the “Late Bloomer”: While players do move, it is rare for a “slow” player to become the “fastest.” One case study showed a player moving from “slow-to-medium” to “fastest” over six years, but this was the exception, not the rule.

Coach’s Note: If a player “slows down” relative to the group, it may not be a loss of ability, but rather a “relative stagnation” while others undergo their growth spurts.

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Practical Applications for Coaches

• Avoid “Speed-Based” De-selection: Don’t cut a player at U13 or U14 just because they aren’t the fastest. Their relative speed ranking is likely to change as they mature.
• Monitor Maturation, Not Just Stopwatches: A player’s speed is heavily tied to their biological age (maturation status). Use growth tracking to put sprint times into context.
• The Influx Factor: New signings in academies are often recruited specifically for their speed, which naturally pushes existing players down the ranking.
• Consistency is Key: Assess speed regularly (e.g., twice a season) in an ecologically valid environment (like 30m sprints on grass) to identify true developmental trends rather than isolated bad days.

Conclusion

While speed is highly genetic, it is not a fixed trait in youth soccer. The “fast players stay fast” mantra is a half-truth at best. By adopting a long-term perspective, coaches can avoid overlooking late-maturing “slow” players who may eventually develop the speed required for the professional level.

This post was generated with the assistance of Gemini based on the original article, with the aim of translating the research into practical insights for coaches and practitioners.