What should a physical test be used for with a young athlete?

Not to say 'you are good' or 'you are not good'. A test should show whether the young athlete is progressing, building strength, coordination and speed, and whether a deficit needs correcting. One test is a snapshot; several tests give a trajectory.

The best player at 13 isn't necessarily the one who will go furthest

Q: Will a 13-year-old who dominates become an elite athlete?

Not necessarily. At that age, much of the performance comes from maturation, size, training experience and sometimes simply a few months of advantage in the birth year. Current level and future potential are not the same thing.

Q: What is the relative age effect?

In categories organised by birth year, a child born in January can be almost a year older than one born in December. At 11, 12 or 13 that gap is huge, and selection systems often favour the older ones.

When a young athlete dominates at 12, 13 or 14, everyone concludes quickly: "he's talented." And when a young athlete is smaller or less explosive, we just as quickly assume he is "behind." Both conclusions can be wrong.

At that age, what we observe is not only sporting potential. It is also maturation, height, strength, growth rate, training experience, technical level, family context, coaching quality — and sometimes simply a few months of advantage within the birth year.

Current performance and potential are not the same

In many sports, selection structures try to identify the best profiles early. On paper it makes sense: spot them early, support them longer.

But research on youth athlete development shows a far more complex reality. Pathways to elite level are rarely linear. Many excellent youngsters never become the best adults, and many elite athletes were not the best of their generation early on. A 2026 Sports Medicine review on the development and promotion of young talent in a national sports context makes exactly this point.

💡 The essential nuance

Youth level is not meaningless. But being among the best at 13 guarantees nothing — and not being there closes no door.

Why we get it wrong so easily with young athletes

In boys especially, puberty creates enormous gaps between youngsters of the same chronological age. Two 14-year-olds can share an ID age and have completely different biological ages.

A more mature youngster is often taller, heavier, stronger and faster. In a match or on a physical test he looks more "talented" — yet part of that advantage simply comes from being physically more mature.

Then there is the relative age effect. In birth-year categories, a child born in January can be almost a year older than one born in December. At 11, 12 or 13 that gap is huge. Selection systems can therefore favour the most mature or the oldest of their category rather than those with the greatest long-term potential.

The danger of early labels

The real problem is not only misjudging. It is what those decisions produce afterwards.

A youngster selected early usually receives more coaching, more visibility, more confidence and more important matches. One left out may lose confidence, train in a less stimulating environment, or drift out of the system. Selection doesn't just measure talent — it also creates developmental differences.

🎯 Track a trajectory, not a ranking

The Full Test (2 h, in Gland) measures strength, power, strength-endurance and asymmetries, then puts every number back into the athlete's age, history and sport.

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What to look at instead

At Off-Field, a test with a young athlete should never say "you are good" or "you are not good." It should answer better questions:

✅ Is the athlete progressing from one test to the next?
✅ Is he building strength, coordination, speed and mobility?
✅ Are the results consistent with his age, history and maturation stage?
✅ Is there a specific deficit to correct?
✅ Can he move, decelerate, jump, land and accelerate well?

One athlete may look average today but improve fast. Another may be strong today and stall if he relies only on a physical head start. See also our article on building a young athlete.

The role of parents and coaches

First mistake: getting carried away. A child dominating at 12 doesn't need to be treated like a future professional. He needs to keep learning, keep loving the sport and develop his body intelligently.

Second mistake: panicking too early. A child who isn't dominant yet isn't failing. He may simply need time, consistency, confidence and an environment that doesn't constantly compare him to more mature peers.

What this changes in the way we work

A physical assessment in a young athlete must always be interpreted carefully. A raw number isn't enough: a vertical jump, a 10 m sprint or a strength test mean different things depending on biological age, sport, training level, recent growth and injury history.

🔑 A snapshot or a trajectory

One test gives a snapshot. Several tests give a trajectory — and the trajectory is far more interesting.

It is the same logic we apply with the clubs and schools we support in team physical preparation.

Conclusion

The best youngster today isn't always the one who goes furthest. Our goal shouldn't be to predict who will be elite, but to develop as many qualities as possible and keep doors open.

The right question isn't "is he already better than the others?" but "are we giving him the best conditions to keep progressing?"

FAQ

Will a 13-year-old who dominates become an elite athlete?

Not necessarily. Much of the performance comes from maturation, size and training experience. Current level and future potential are different things.

What is the relative age effect?

In birth-year categories, a January-born child can be almost a year older than a December-born one. At 12 that gap strongly favours the older ones during selection.

What should a physical test be used for?

To track progress and identify a specific deficit — not to attach a label. One test is a snapshot; several give a trajectory.

🎯 Build, don't label

Objective assessment in Gland, then a physical preparation plan matched to the athlete's age and growth stage.