Does Lifting Weights Stunt Growth?

Lifting weights does not stunt growth. Decades of research on children and adolescents who participate in resistance training have found no measurable reduction in height or growth rate compared to peers who don’t train. An evidence-based review in the Clinical Journal of Sport Medicine concluded that experimental resistance training programs did not influence growth in height or weight of pre- and early-pubertal youth.¹ Yet the myth persists, fueled by reasonable-sounding concerns about developing bones and a few grains of truth buried under layers of misunderstanding.

Where the Myth Came From

The idea that lifting weights stunts a young person’s growth has circulated among parents, coaches, and even some physicians for decades. Part of its staying power comes from conflating two different things: catastrophic growth plate injuries and routine resistance training. Growth plates are the cartilage zones near the ends of long bones where new bone tissue is added during childhood and adolescence. They are, structurally speaking, weaker than the surrounding mature bone, which means a severe impact or abnormal force could theoretically damage them and disrupt growth.² That much is true. But the leap from “growth plates can be injured” to “squats will make your kid shorter” skips over everything the research actually shows about how injuries happen and how rare they are in supervised training.

Another contributor to the myth is the appearance of certain elite weightlifters and gymnasts, who tend to be shorter than average. People see a short Olympic lifter and assume the training caused it, when in reality shorter body proportions confer a biomechanical advantage in those sports. The athletes were selected partly because of their stature, not shortened by their training. A narrative review of the literature on weightlifting for young people noted that although the sport has been “criticized in some circles,” the injury rate is relatively low and severe injuries are uncommon when training is supervised and age-appropriate.³

What Actually Injures a Growth Plate

Growth plates close at different ages depending on the bone, generally finishing somewhere in the late teens for most people. Until they close, they represent a structural weak link. But the forces that damage them are not the kind generated by a controlled squat or dumbbell press. Growth plate injuries typically result from shearing, avulsion, or compressive forces caused by severe twisting, sudden falls, or direct blows.⁴ Think of a hard tackle in football or a bad landing in gymnastics, not a bench press with proper form.

This distinction matters. Growth plate fractures do happen in youth sports, but they overwhelmingly occur in contact and collision sports, not in the weight room. When injuries have been reported in young weightlifters, the majority have been classified as accidental, and the underlying cause is usually a lack of qualified supervision, poor technique, or inappropriate loads rather than something inherent to the act of lifting.⁵ In other words, the danger isn’t the weight itself; it’s what happens when nobody teaches a kid how to use it safely.

How Forces from Lifting Compare to Running and Jumping

One of the more revealing pieces of context is how the compressive forces on the spine during weight training stack up against everyday physical activities. A study comparing spinal loading during circuit weight training and a six-kilometer run found that the temporary shrinkage in spinal height (a proxy for how much the spine gets compressed) was not significantly different between the two activities.⁶ Running, jumping rope, playing basketball on a hard court, even horsing around on a playground all apply repetitive compressive and impact forces to growing bones. Nobody worries that recess stunts growth.

Growth plates do respond to mechanical loading, and their biology is sensitive to sustained or cyclic forces.⁷ But “responds to” does not mean “is damaged by.” In fact, moderate mechanical loading is part of the normal signaling environment that helps bones grow and remodel. It is extreme, uncontrolled, or repetitive overloading that crosses the line into risk, and well-designed youth training programs are specifically structured to stay well below that threshold.

What the Height Data Actually Show

The cleanest way to settle the question is to look at studies that measured kids before and after resistance training programs and compared them to controls. An evidence-based review that pulled together controlled trials on young people found that resistance training had no effect on growth in height.¹ Kids who lifted grew at the same rate as kids who didn’t. Changes in body composition were small and variable.

This is about as close to a definitive answer as exercise science can offer on this question. Randomized controlled trials tracking height over months of supervised training, repeated across multiple research groups, consistently show no suppression of growth. If resistance training had any meaningful stunting effect, it would have shown up somewhere in this body of literature. It hasn’t.

Hormonal Responses in Young Lifters

Growth in childhood and adolescence is driven largely by hormones, especially growth hormone (GH) and insulin-like growth factor I (IGF-I). Some parents worry that the stress of heavy exercise might interfere with these growth signals. The reality is more nuanced and, on balance, reassuring.

A study examining hormonal responses to a single session of free-weight resistance training in trained boys found that both prepubertal and pubertal participants showed a significant increase in growth hormone levels after exercise.⁸ The IGF-I and testosterone responses differed between age groups, with pubertal boys showing a greater change, which reflects the expected maturation of the hormonal system rather than any harm from lifting. In short, a training session appears to stimulate rather than suppress the hormones involved in growth.

That said, there is an important caveat. Some research has noted that training can temporarily reduce certain components of the GH/IGF-I axis, likely through the elevation of inflammatory signaling molecules that are a normal part of the body’s response to exercise stress.⁹ These are transient, acute responses, not chronic suppression. The body recovers, and over time the net hormonal environment in a training young person is not measurably different from one who doesn’t train, at least in terms of growth outcomes.

When There Is a Legitimate Concern

If the core myth is wrong, is there any scenario where training could actually interfere with growth? Yes, but the culprit isn’t the lifting itself. It’s what surrounds it.

The biggest genuine risk comes from energy deficit. Young athletes who restrict food intake to make a weight class or maintain a certain body composition can disrupt the hormonal systems that regulate growth, maturation, and bone health. A systematic review of weight cycling practices in youth combat sports found that intentional energy deficits combined with dehydration during training could disturb metabolic and hormonal regulation, affecting growth, maturation, menstrual cycles, and raising the risk of stress fractures.¹⁰ The problem here is undereating and overtraining, not the act of lifting a barbell.

Overtraining more broadly is also worth watching. A scoping review on school-age athletes found a potential association between high training loads and elevated injury risk, though the relationship is multifactorial and the evidence isn’t fully consistent.¹¹ An adolescent who lifts five days a week, plays two competitive sports, gets six hours of sleep, and barely eats enough to keep up with their growth spurt is a different story from one who follows a structured, moderate training program with adequate rest and nutrition. The distinction between appropriate volume and chronic overloading is where responsible coaching earns its value.

The Benefits That Get Lost in the Fear

The irony of the growth-stunting myth is that it scares parents away from an activity that actually benefits developing bones and bodies in several meaningful ways.

Bone density is one of the clearest wins. A systematic review of the evidence found strong support for the effectiveness of weight-bearing exercise on bone mass accumulation, especially during the growing years.¹² Building a denser skeleton during childhood and adolescence is one of the most effective ways to reduce the risk of osteoporosis later in life. Strength training also has the potential to improve motor skills and better prepare young athletes for the physical demands of their sports.¹³

Beyond the physical, resistance training has measurable psychological benefits for young people. A meta-analysis examining self-concept outcomes found that youth who participated in resistance training showed meaningful improvements in self-efficacy, perceptions of their physical strength, physical self-worth, and global self-worth.¹⁴ For a teenager navigating the social pressures of school and puberty, feeling competent and strong in their body is not a trivial benefit.

The metabolic picture is less clear-cut. A systematic review found only limited evidence that resistance training alone improves metabolic markers like insulin sensitivity in youth, though methodological limitations in the available studies make it hard to draw firm conclusions.¹⁵ A separate meta-analysis found no statistically significant effect of resistance training on insulin sensitivity in young people, suggesting it works best as a complement to aerobic exercise rather than a standalone metabolic intervention.¹⁶ So resistance training isn’t a cure-all, but the benefits it does deliver, stronger bones, better coordination, increased confidence, are substantial.

What the Professional Organizations Say

The major sports medicine and strength training organizations have weighed in on this question, and the consensus is clear. The National Strength and Conditioning Association’s position statement recognizes that the benefits associated with adult resistance training are attainable by children and adolescents who follow age-specific guidelines, and notes that the qualified acceptance of youth resistance training by medical, fitness, and sport organizations has become essentially universal.¹⁷ Similar positions have been adopted by the American Academy of Pediatrics, the British Association of Sport and Exercise Sciences, and other professional bodies.

The common thread across all of these guidelines is that supervision and appropriate programming are non-negotiable. A qualified coach who understands how to scale exercises for a growing body, who prioritizes technique over load, and who builds in adequate recovery is the difference between a beneficial training program and a risky one.⁵ The guidelines are not saying “let kids do whatever they want in the weight room.” They are saying that with competent guidance, resistance training is safe and beneficial, and that avoiding it out of fear is a missed opportunity.

The Persistent Gap Between Evidence and Parental Belief

Despite the scientific consensus, many parents remain skeptical. A study examining parental perceptions of youth strength and conditioning found that myths and misconceptions about its safety continue to prevent widespread uptake.¹⁸ The growth-stunting myth is one of the most common of these, and it tends to be self-reinforcing: a parent who believes it keeps their child out of the weight room, which means they never get the chance to see that the fear was unfounded.

Pediatricians and family doctors sometimes contribute to the problem, too. Older medical guidance was more cautious about youth resistance training, and doctors who trained in an era when the default advice was “no lifting until the growth plates close” may still pass that along. The evidence base has shifted substantially over the past two decades, but clinical practice doesn’t always keep pace with the literature. If a doctor tells you your twelve-year-old shouldn’t touch a weight, it’s worth asking what specific concerns they have and whether they’re drawing on current position statements from organizations like the NSCA or the AAP.

Practical Guidelines for Young Lifters

If you’re a parent considering resistance training for your child, or a teenager interested in starting, here are the principles that emerge from the research:

• Supervision first: A qualified coach or trainer who understands youth physiology should be present for all sessions, especially early on. Most training injuries in young people trace back to unsupervised sessions or poor instruction.
• Technique before load: Learning the movement patterns with light weights or bodyweight is the foundation. Adding heavier loads should come only after the mechanics are solid and consistent.
• Progressive, not maximal: Youth programs should emphasize gradual progression. One-rep max attempts and very heavy loads carry more risk and aren’t necessary for building strength at this age.
• Adequate nutrition: A growing body needs sufficient calories and protein to support both training and normal development. Restricting food to control weight or body composition is where real harm to growth can occur.
• Rest and recovery: Two to three sessions per week with rest days in between is a common recommendation. Overtraining is a real risk, especially for multi-sport athletes who may be accumulating physical stress from multiple directions.
• Variety: A well-rounded program that includes flexibility, coordination, and aerobic work alongside resistance training tends to produce better long-term outcomes than focusing exclusively on lifting.

These guidelines aren’t exotic or complicated. They amount to common-sense coaching applied to a population that’s still growing. The evidence consistently shows that when these principles are followed, resistance training is not only safe for young people but actively beneficial for their bones, muscles, coordination, and self-confidence.

Why Age at Starting Matters Less Than You Think

A question parents often ask is what age is safe to start. The research suggests there isn’t a sharp cutoff. Children as young as seven or eight have participated in supervised resistance training studies without adverse effects on growth. The limiting factor isn’t chronological age so much as emotional maturity, the ability to follow instructions, and the willingness to practice good form rather than ego-lift. A focused ten-year-old who listens to a coach and performs bodyweight exercises and light dumbbell movements with good technique is at very low risk. A distracted fourteen-year-old loading up a barbell unsupervised to impress friends is at higher risk regardless of being older.

The hormonal environment does change with puberty. Before puberty, kids still gain strength from resistance training, but the gains come primarily from neural adaptations, basically the nervous system getting better at recruiting muscle fibers, rather than from significant muscle hypertrophy. Pubertal and post-pubertal adolescents experience greater hormonal responses to training, including bigger spikes in testosterone and IGF-I, which drive more visible muscle growth.⁸ This doesn’t mean prepubertal training is pointless; it means the visible results look different. Strength, coordination, and bone health improve regardless of pubertal stage.