Someone you trust told you not to lift weights until you stopped growing.
A parent, a coach, maybe a doctor. The rule felt protective, and the logic felt obvious: heavy loads pressing down on bones that haven't finished forming.
That warning started with a handful of injury reports from the 1970s and 1980s: teenagers who hurt growth plates while lifting alone, with maximal loads and no coaching. The injuries were real. But the jump from unsupervised max-outs to every teenager touching a barbell happened without a single controlled study behind it. Since then, those studies have been done.
Does Lifting Weights Actually Stunt Growth in Teenagers?
An evidence review in the Clinical Journal of Sport Medicine gathered 22 experimental resistance training studies in children and early adolescents. Not one showed that training affected growth in height or weight. The kids who lifted and the kids who didn't ended up the same height.
The specific fear behind the rule was growth plate damage. Across every prospective study in the review, zero growth plate injuries were reported. The few case reports that seeded the myth involved teenagers lifting maximal loads without supervision or proper technique. Structured programs with coaching produced a total of three minor injuries across ten monitored studies: two shoulder strains and one bruised thigh from a dropped bar.
The mechanism explains why. Before puberty, strength gains come from the nervous system, not from muscle growth. The brain gets better at activating more muscle fibers and coordinating their timing. Muscles gain strength without adding size. If the muscles are not growing substantially, the compressive load on growth plates that the myth feared had no physical basis.
But the findings go further than just absence of harm. A seven-member expert panel for the National Strength and Conditioning Association reviewed 258 studies and published a position statement. Their conclusion: resistance training actively strengthens growing bones. Children who train show bone mineral density well above their peers. Growth cartilage in younger kids may actually be tougher than in older teenagers. What the prohibition aimed to prevent is exactly what strengthens the bones it was trying to protect.
Per hour of participation, resistance training was roughly 67 times safer than rugby.
The safety comparison makes the point sharper. In a year-long tracking study of youth sports injuries, resistance training accounted for 0.7 percent of all injuries. Football caused 19 percent. Basketball caused 15 percent. Per hour of participation, resistance training was roughly 67 times safer than rugby. The teenager told to skip the weight room for safety is often already playing a sport that carries dramatically higher risk.
The rule you were given came from a place of care, but the evidence beneath it has not survived testing. Twenty-two studies, a 258-reference institutional review, and decades of prospective monitoring all converge on one answer: properly supervised resistance training is safe for teenagers and children as young as five or six. It does not stunt growth. It builds stronger bones and reduces sports injuries. The one qualifier every study and every position statement shares is the word supervised: proper technique, age-appropriate programming, and a coach who knows what they are doing. The myth was never about training. It was about the absence of coaching.
If the growth question is settled, the next one becomes fuel. Teenagers have their own protein math, and the numbers look different from what most gym advice assumes.