Meta-analysis: RT produces large strength gains in children & adolescents (pooled ES 1.12)
Trainability INCREASES with age and maturity, with no special boost during puberty
Key Findings
Overall weighted effect size for muscle strength 1.12 (95% CI 0.9–1.3), significantly greater than 0 (P < .01), in healthy prepubertal and postpubertal children and adolescents under 18 y. Muscle endurance and motor-performance tests (e.g. vertical jump) were excluded.
"Maturity" was a significant moderator (z = 2.50; P = .01): the ability to gain strength seems to increase with age and maturational status — but with no noticeable boost during puberty.
Positive correlations for duration (r = 0.28; P = .02) and frequency (r = 0.26; P = .03); the authors conclude study duration and the number of sets performed have a positive impact on the outcome.
Not from this paper: the "pre-pubertal gains are predominantly neural" mechanism sits in the 2014 consensus (REF-600), not in this meta-analysis.
Practical Application
Pooled across controlled trials in under-18s, resistance training raised strength by a large effect (ES 1.12), the response grew with age and maturity rather than shrinking, and puberty gave no special window — strength is trainable across the whole youth span, so supervised youth strength work is justified at any age.
Program for progression: longer programs and more sets delivered more (token sessions won't); expect the absolute response to be smaller in younger, less mature children and larger in adolescents.
Inference, not tested: strength gains in the youngest children come with little visible muscle growth (see REF-600 for the neural-adaptation framing).
Limitations
Heterogeneous youth designs, including non-randomized trials; the abstract does not report a pooled estimate by age subgroup, only that maturity moderates the effect; youth population, not adult prescription.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A+: a single meta-analysis (A+ requires several concordant reviews); included trials are a mix of randomized and non-randomized
Content correction 2026-09-27
Title and lead said effects were "larger in children than adolescents" -> the abstract says trainability increases with age and maturational status, with no boost at puberty (opposite direction).
"Greater gains with higher training intensity" -> the abstract reports duration and frequency (and number of sets) as positive moderators; intensity is not mentioned.
Added the pooled ES 1.12 (0.9–1.3) and the moderator statistics; level A+ -> A (single meta-analysis); Tier "N/A" -> Tier 0-2.