Youth athletes who specialise in one sport had double the odds of injury

Design

systematic review and meta-analysis of 15 observational studies, PROSPERO registered

Population

youth athletes, specialised in one sport versus participating in several

Primary outcome

injury occurrence

Effect

pooled odds ratio 2.00 (95% CI 1.58–2.55), p<0.001; moderated by sport type but not age, sex or design

Parents ask whether their child should commit to one sport, and the answer has usually been offered as opinion. This meta-analysis pooled 15 studies of the relationship between sport specialisation and injury in youth athletes, assessing quality with the JBI checklist and the Newcastle-Ottawa Scale, with prospective registration.

The pooled odds ratio for injury with specialisation was 2.00 (95% CI 1.58 to 2.55, p<0.001). Heterogeneity was moderate, sensitivity analyses stable and no publication bias detected. Sport type significantly moderated the relationship, but age, sex, study design, injury measurement, injury mechanism and anatomical location did not — the association held across contact and non-contact sports, and specialised athletes had higher pooled odds of injury than those playing several sports.

That the moderators were mostly null is what makes this usable at the clinic desk. You do not need to know which sport, how old the child is, or which body part to give the advice: diversified participation is associated with fewer injuries. The conversation to have is with the parent who has been told that early specialisation is how a child reaches an elite level, because it is the parent rather than the child who decides. Say plainly that the evidence is observational, that it cannot prove specialising causes the injury, and that the association is consistent enough to act on anyway.

• Ask how many sports the child plays, and how many months a year they play the main one
• Advise diversified participation and a genuine off-season from the primary sport
• Do not reserve this advice for children who have already been injured
• Frame it for the parent as well as the child — the decision is usually theirs
• Note that sport type mattered but age and sex did not, so the advice is the same across your clinic

Why it matters

It gives an answer to the single commonest sports question in paediatric practice, which has until now been given as opinion.

Don't overread it

These are observational studies — children who specialise also train more hours, and the design cannot separate the two.

The statistics, in plain English

An odds ratio of 2.00 with an interval of 1.58 to 2.55 is a consistent doubling, but with moderate heterogeneity between studies, which means the true effect varies by setting rather than being one number. The null moderation results are reassuring rather than weak: when a relationship does not change with age, sex, design or how injury was measured, it is less likely to be an artefact of any one of those. Absence of publication bias here means small negative studies were probably not missing.

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