Youth & adolescent training

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Connected to · 3

regulates · 3

Neural drive vs hypertrophy
Before puberty, children do get stronger from strength training, but the progress lands mainly in the nervous system: more motor units are recruited, they fire more densely and the opposing muscle learns to let go, while muscle size barely changes. After puberty, the same training converts more readily into thicker muscle. This is a simplification that helps understanding, not a switch anyone has measured.
Bone
Bone is living tissue, and repeated but tolerable pressure along its long axis makes it stronger, so supervised, gradually progressed resistance training helps adolescents build bone density. Well-designed training has not been seen to affect growth in height or harm the growth plates; the injuries that get reported mostly happen in unsupervised settings with unsafe technique.
Growing taller
Children grow taller at the growth plates near the ends of the bones, the same still-growing cartilage that youth training has to respect. In controlled strength-training trials in children, growth in height was not affected; the claim that lifting stunts growth is not supported by the trials so far.

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Does lifting stunt growth?

EVIDENCEGUIDE 1 · REVIEW 4

READ THE ORIGINAL

With someone watching, the movement done right and the load raised gradually, strength training is safe for children and teenagers aged 5–18, and it reliably makes them stronger.

The idea that lifting stunts a child's growth did not come from nowhere. In the 1970s–80s there were a few case reports of growth-plate injuries in adolescents, mostly when nobody was supervising, technique was poor, and the young lifter was straining at a maximal weight. Those stories were passed along, and slowly widened into "any kind of resistance training is dangerous."

The current evidence paints a different picture. Behringer 2010 pooled 42 controlled trials in children and adolescents and found clear strength gains after resistance training. The Faigenbaum 2009 position statement from the National Strength and Conditioning Association (NSCA) and the 2020 clinical report from the American Academy of Pediatrics (AAP), written by Stricker and colleagues, both come down on the side of recommending it, not discouraging it.

As for height: twin studies put about 80–90% of adult height down to genes, with nutrition, hormones, sleep and general health sharing the rest. In the training trials Malina 2006 reviewed, growth in height and weight was not affected. Those trials lasted only months, so final adult height was never tracked directly, but none of them showed supervised training making children shorter.

Educational content, not medical advice — consult a clinician.

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Youth & adolescent training

Story

Connected to · 3

regulates · 3

Neural drive vs hypertrophy
Before puberty, children do get stronger from strength training, but the progress lands mainly in the nervous system: more motor units are recruited, they fire more densely and the opposing muscle learns to let go, while muscle size barely changes. After puberty, the same training converts more readily into thicker muscle. This is a simplification that helps understanding, not a switch anyone has measured.
Bone
Bone is living tissue, and repeated but tolerable pressure along its long axis makes it stronger, so supervised, gradually progressed resistance training helps adolescents build bone density. Well-designed training has not been seen to affect growth in height or harm the growth plates; the injuries that get reported mostly happen in unsupervised settings with unsafe technique.
Growing taller
Children grow taller at the growth plates near the ends of the bones, the same still-growing cartilage that youth training has to respect. In controlled strength-training trials in children, growth in height was not affected; the claim that lifting stunts growth is not supported by the trials so far.

Read full story

Stop 1/4

Does lifting stunt growth?

EVIDENCEGUIDE 1 · REVIEW 4

READ THE ORIGINAL

With someone watching, the movement done right and the load raised gradually, strength training is safe for children and teenagers aged 5–18, and it reliably makes them stronger.

The idea that lifting stunts a child's growth did not come from nowhere. In the 1970s–80s there were a few case reports of growth-plate injuries in adolescents, mostly when nobody was supervising, technique was poor, and the young lifter was straining at a maximal weight. Those stories were passed along, and slowly widened into "any kind of resistance training is dangerous."

The current evidence paints a different picture. Behringer 2010 pooled 42 controlled trials in children and adolescents and found clear strength gains after resistance training. The Faigenbaum 2009 position statement from the National Strength and Conditioning Association (NSCA) and the 2020 clinical report from the American Academy of Pediatrics (AAP), written by Stricker and colleagues, both come down on the side of recommending it, not discouraging it.

As for height: twin studies put about 80–90% of adult height down to genes, with nutrition, hormones, sleep and general health sharing the rest. In the training trials Malina 2006 reviewed, growth in height and weight was not affected. Those trials lasted only months, so final adult height was never tracked directly, but none of them showed supervised training making children shorter.

Educational content, not medical advice — consult a clinician.