Properly supervised weight training does not stunt growth in children or adolescents. This is one of the most persistent myths in fitness, but decades of research and multiple medical position statements agree: resistance training has no apparent adverse effect on height, growth plates, or skeletal development when performed correctly. The concern has a logical-sounding origin, which is probably why it has survived so long, but the evidence points in the opposite direction.
Where the Myth Comes From
The worry centers on growth plates, the strips of cartilage near the ends of long bones where lengthening actually happens. These plates are softer than mature bone, and in theory, a severe enough injury to a growth plate could cause it to fuse prematurely, stopping that bone from reaching its full length.1PubMed Central. The Effects of Physical Activity on the Epiphyseal Growth Plates: A Review of the Literature on Normal Physiology and Clinical Implications That much is true, and it is the grain of fact that gave the myth its staying power. Growth plate fractures do occur in young people, most commonly from falls, contact sports, and car accidents. The leap the myth makes is from “growth plate injuries are possible” to “lifting weights causes growth plate injuries,” and that leap is not supported by the research.
Case reports of growth plate injuries in young weightlifters do exist, but when researchers have looked at them closely, the injuries were overwhelmingly tied to unsupervised training, poor technique, or inappropriate loads. Skeletal immaturity and anabolic steroid abuse have also been identified as risk factors for weight-training injuries in young people.2PubMed. Weight training injuries: part 1: diagnosing and managing acute conditions In other words, the problem was never the act of lifting itself but the conditions under which it was done.
What the Research Actually Shows About Height
When scientists have directly measured whether resistance training affects how tall kids grow, the answer has been a consistent no. A review of experimental resistance training programs in pre- and early-adolescent youth found that these programs did not influence growth in height or weight, and any changes in body composition were small and variable.3PubMed. Weight training in youth-growth, maturation, and safety: an evidence-based review The American Academy of Pediatrics has stated that appropriate strength-training programs have no apparent adverse effect on linear growth, growth plates, or the cardiovascular system.4Pediatrics. Strength Training by Children and Adolescents
That finding has been echoed by the National Strength and Conditioning Association and the Canadian Society for Exercise Physiology, among others. Youth who strength-train under qualified supervision can safely improve their strength and overall health without compromising their development.5PubMed Central. Strength training in children and adolescents: raising the bar for young athletes? The sheer volume of agreement across independent medical and sports science bodies is worth noting, because these organizations do not issue position statements lightly, and they have all landed in the same place.
How Kids Actually Get Stronger
One reason weight training does not affect growth the way people fear is that strength gains in children work differently than in adults. When an adult lifts weights consistently, muscles grow larger. When a child does the same thing, the muscles do not change much in size. Instead, the nervous system gets better at recruiting the muscle fibers that are already there. Research on high-intensity strength training in children found that while peak torque of knee muscles increased, muscle size did not change, suggesting that neural factors rather than hypertrophy accounted for the strength gains.6PubMed. Effects and mechanisms of strength training in children
This means a child who strength-trains is not loading their skeleton the way a heavily muscled adult would. The forces involved are lower, the adaptations are largely in the brain and spinal cord rather than in the tissues surrounding growth plates, and the risk profile is fundamentally different from what many parents imagine when they picture a teenager under a barbell.
Lifting Is Actually Good for Growing Bones
Not only does resistance training not harm bone development, it appears to help it. Mechanical loading, the kind of stress that muscles place on bones during lifting, is one of the strongest stimuli for bone mineral accrual during adolescence. A study comparing adolescent weightlifters to non-lifting peers found that bone mineral density values were greater in weightlifters across multiple body segments, and the effect was dose-dependent: elite weightlifters had higher density than non-elite lifters, who in turn had higher density than controls.7Journal of Clinical Densitometry. Effects of Different Levels of Weightlifting Training on Bone Mineral Density in a Group of Adolescents
The benefit is especially striking in sports that do not provide much impact loading on their own. A 12-month study of adolescent swimmers found that adding resistance training improved bone mineral density in the upper limbs and the whole body compared to swimming alone. Swimming-only groups actually lost spine bone density over the study period, while every other group gained it.8PubMed Central. Resistance training presents beneficial effects on bone development of adolescents engaged in swimming but not in impact sports: ABCD Growth Study For young athletes in low-impact sports, resistance training may be doing more for their long-term skeletal health than the sport itself.
When Injuries Do Happen
None of this means weight training is risk-free for young people. Injuries can and do occur. But the pattern of those injuries is revealing. Reviews of injury reports in youth weightlifting and powerlifting have found that while injuries have occurred, the majority were classified as accidental, with lack of qualified instruction, poor exercise technique, and inappropriate training loads explaining most of the reported problems.9PubMed Central. Resistance training among young athletes: safety, efficacy and injury prevention effects This is an important distinction. A kid who loads too much weight on a barbell with no one watching is at risk, just as a kid who rides a bike without a helmet or plays football without proper coaching is at risk. The activity is not inherently dangerous; the absence of supervision is.
Injury rates in supervised youth resistance training are actually lower than in many popular youth sports. Soccer, basketball, and football all produce more injuries per hour of participation than properly run strength-training sessions. In fact, comprehensive conditioning programs that included resistance training have been shown to reduce the number and severity of sports-related injuries in adolescent athletes, including high school football and soccer players.10The Journal of Strength & Conditioning Research. Youth Resistance Training: Updated Position Statement Paper From the National Strength and Conditioning Association So resistance training can serve as injury prevention for the sports that parents tend to worry less about.
What Can Actually Stunt Growth
If lifting weights is not the threat to height that people assume, what actually can interfere with growth? The answer that gets far less attention than it should is nutrition. Exercise of any kind, whether it is resistance training, distance running, or gymnastics, increases caloric demand. If a young person is training hard but not eating enough to cover both the energy cost of exercise and the energy cost of growing, growth can be temporarily or even permanently affected. Research has shown that exercise can block the expression of statural growth by competitively removing the nutritional support needed for it, and while catch-up growth is possible, permanent stunting can occur depending on the timing and severity of the energy deficit.11PubMed. The effects of exercise on growth
This is where the data on female gymnasts gets interesting and often confused. Some studies have found that female gymnasts experience attenuated growth during periods of intense training, followed by catch-up growth after reducing training or retiring. But the evidence is tangled. Gymnasts tend to be short even before they begin training, suggesting selection bias, and the gymnastics environment involves confounding factors beyond just the physical training: caloric restriction, psychological stress, and extreme training volumes that far exceed what a typical teenage lifter encounters.12PubMed Central. Does gymnastics training inhibit growth of females? Whether catch-up growth is complete remains uncertain. But the takeaway is that if growth interference is happening, chronic energy deficiency is the more likely culprit than mechanical loading.
For a teenager who lifts weights a few times per week and eats adequately, the caloric drain is modest and easily compensated. The growth concern becomes real only in situations of extreme training volume combined with inadequate nutrition, which is not what most youth strength programs look like.
Growth Spurts, Timing, and Vulnerability
Adolescents are not one uniform group, and the timing of puberty matters for training decisions. Female athletes tend to hit peak height velocity and the onset of puberty earlier, roughly between ages eight and thirteen, while males experience the same process later and over a longer window that can extend into late adolescence.13Journal of Human Sport and Exercise. Sex differences in growth, skeletal maturation, and training load in youth sports: Implications for long-term athletic development During periods of rapid growth, coordination and movement efficiency can temporarily decline, and susceptibility to overuse injuries may increase, especially under high training loads with inadequate recovery.
This does not mean teens in a growth spurt should stop lifting. It means that programming should be adjusted. Lighter loads with more emphasis on technique, longer warm-ups, and attention to how the athlete is feeling on a given day are all reasonable accommodations. A coach who understands that a kid shooting up three inches in six months might temporarily move less efficiently is a coach who keeps that kid safe. The risk is not the weights; it is ignoring the biological reality of the moment.
What Happens Hormonally When Young People Lift
A common assumption is that resistance training floods the body with growth hormone and testosterone, which somehow interferes with the delicate endocrine balance of adolescence. The hormonal picture is more nuanced. A single bout of resistance training does produce a temporary spike in growth hormone in young subjects, roughly a fivefold increase from resting levels in one study of young adults.14PubMed. Effects of progressive resistance training on growth hormone and testosterone levels in young and elderly subjects But these are acute, short-lived spikes that return to baseline within hours, not chronic elevations that would reshape development.
In children and adolescents specifically, a meta-analysis of exercise training studies found that the changes in growth hormone and IGF-I (a key mediator of growth) were small and did not reach statistical significance when children and adolescents were analyzed together.15PubMed Central. Effects of Resistance and Endurance Training Alone or Combined on Hormonal Adaptations and Cytokines in Healthy Children and Adolescents: A Systematic Review and Meta-analysis Pubertal boys do show a greater acute testosterone and IGF-I response to a resistance session compared to prepubertal boys, but both groups show a rise in growth hormone after exercise.16PubMed Central. Hormonal and inflammatory responses in prepubertal vs. pubertal male children following an acute free-weight resistance training session None of this evidence points toward hormonal disruption. If anything, the modest, transient hormonal responses to resistance exercise are part of the normal adaptive process, not a threat to it.
Practical Guidelines for Young Lifters
If you are a parent or coach wondering what safe youth resistance training actually looks like, the recommendations from sports medicine organizations are fairly consistent. The Canadian Society for Exercise Physiology recommends that children and adolescents perform low- to moderate-intensity resistance exercise two to three times per week on non-consecutive days, starting with one to two sets and progressing to up to four sets of eight to fifteen repetitions across eight to twelve exercises.17PubMed. Canadian Society for Exercise Physiology position paper: resistance training in children and adolescents The emphasis at every stage is on learning movement patterns before adding load.
Several themes run through nearly all published guidelines:
- Supervision is non-negotiable: A qualified coach or trainer should be present for every session, especially early on, to correct form and manage progression.18PubMed Central. Resistance training for children and adolescents
- Technique before load: Kids should be able to perform an exercise with proper form through the full range of motion before any weight is added. Body-weight exercises are a fine starting point.
- Gradual progression: Increases in weight should be small and tied to demonstrated competence, not age or ego.
- No maximal lifts for beginners: One-rep-max testing is generally discouraged for prepubescent children. Submaximal sets in the eight-to-fifteen rep range are both safer and effective for building a strength base.
These are not complicated or expensive requirements. A knowledgeable coach, a reasonable starting load, and a focus on doing things right before doing them heavy will cover the vast majority of safety concerns. The evidence is clear that the benefits of youth resistance training, including improved strength, better bone density, reduced sports-injury risk, and long-term athletic development, far outweigh the risks when those basic conditions are met.19PubMed Central. Strength and Conditioning in the Young Athlete for Long-Term Athletic Development
Olympic Weightlifting and Youth Competition
Some parents draw a sharp line between general strength training and competitive weightlifting, the snatch-and-clean-and-jerk variety. This distinction is worth addressing, because Olympic-style weightlifting involves catching heavy loads overhead and in deep squats, which sounds more alarming than a set of dumbbell presses. Yet the evidence here is also reassuring. A narrative review of weightlifting in children and adolescents found that while injuries can occur during weightlifting, the incidence and rate of injury are relatively low, and severe injuries are uncommon.20PubMed Central. Weightlifting for Children and Adolescents: A Narrative Review Weightlifting training also improved body composition, strength, and power in young athletes.
Countries with long traditions of youth weightlifting, including China, Turkey, and several Eastern European nations, begin structured training at young ages and have not reported systemic growth problems in their lifters. The key qualifier remains the same: the training must be age-appropriate, properly supervised, and accompanied by competent technical instruction.21Journal of Sport Science & Innovation. A Review Study on Olympic Weightlifting A thirteen-year-old learning to snatch under a certified coach is in a fundamentally different situation from a thirteen-year-old mimicking a YouTube video in a garage.