Weight training for teenagers: does it stunt growth? What the studies say
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Weight training does not stunt growth: in supervised programmes height and weight develop normally and injuries are rare. What does cause accidents is training unsupervised. What studies and consensus statements say, the benefits and how to start step by step.
Between 2002 and 2005, emergency departments in the United States treated thousands of weight-training injuries in people aged 8 to 30. Gregory Myer and his team at Cincinnati Children's Hospital reviewed 4,111 of those cases and found something that undermines a very common fear: in children aged 8 to 13, two thirds of injuries were to the hands and feet and were described with words such as “dropped” or “pinched”. They were not strains from lifting too much, but accidents.
Sprains and muscle strains, on the other hand, increased with age: adults were injured by the effort itself more than youngsters were. The study concluded that most youth injuries could be prevented with more supervision and stricter safety rules. Now for the other questions: growth, the real benefits and how to start well.
Does weight training stunt growth?
It is the most repeated myth, and the evidence does not support it. Robert Malina, a leading expert in child growth and maturation, reviewed in 2006 the 22 experimental studies published in children and adolescents in the early stages of puberty. The programmes, usually 2 or 3 days a week for 8 to 12 weeks, with machines and free weights, did not affect the height or weight of the participants and clearly improved their strength.
The idea that weights “crush” growth plates comes from isolated injuries caused by accidents or very poor technique, not from well-designed training. It is true that growth plates are more vulnerable to a blow or a fall than adult bone, which is why technique and supervision matter more than the load.
| Age group | Most typical injury | Main cause |
|---|---|---|
| 8-13 years | Hands and feet, with more fractures than in other groups | Accidents: dropped weights and pinched fingers |
| 14-18 years | A mix of accidents and overexertion | Accidents fall and sprains and strains rise |
| 19-30 years | Sprains and muscle strains | The lifting effort itself |
How many injuries happen in a supervised programme?
Very few. Of the 22 studies in Malina's review, only 10 recorded injuries systematically, and between them they reported 3. The calculated rates were 0.176, 0.053 and 0.055 injuries per 100 hours of participation. The programmes had something in common: supervision and few participants per instructor.
What actually protects young lifters: someone teaching technique and watching the session, weights put back where they belong and no training alone at home with loose plates. Myer's study points precisely to the lack of supervision as the source of most accidents.
Is strength training worthwhile before 18?
Yes, very much so. In 2010, Michael Behringer and his team at the German Sport University Cologne analysed trials in under-18s and obtained a mean effect size of 1.12 on muscle strength, a large effect. The ability to gain strength increased with age and maturity, although with no striking jump during puberty, and longer programmes with more sets gave better results.
In young athletes, the meta-analysis by Lesinski, Prieske and Granacher (2016), with 43 studies of participants aged 6 to 18, found moderate effects on strength and vertical jump, and small effects on speed, agility and sport-specific performance.
| Variable | Most effective in the analysis | How to interpret it |
|---|---|---|
| Programme length | More than 23 weeks | Strength in young people is built over months of consistency |
| Sets per exercise | 5 | A destination, not a starting point |
| Reps per set | 6-8 | With technique already established |
| Intensity | 80-89% of 1RM | Heavy loads only after a supervised progression |
| Rest between sets | 3-4 minutes | Long rests to lift with quality |
A word of caution about that table: it describes what worked best in young athletes who already trained with a coach. A teenager starting from scratch first needs weeks of technique work with light loads.
What scientific organisations say
The 2014 international consensus, led by Rhodri Lloyd (Cardiff Metropolitan University) together with Avery Faigenbaum and other specialists in sports medicine and paediatrics, grew out of the official position of the UK Strength and Conditioning Association and is endorsed by many organisations. The US National Strength and Conditioning Association (NSCA) already argued in 2009 that many of the benefits of strength training in adults are within reach of children and adolescents, provided they follow age-appropriate guidelines with supervision.
The World Health Organization includes it in its 2020 recommendations: an average of 60 minutes a day of moderate or vigorous activity for children and adolescents, and regular muscle-strengthening activities at all ages.
How to start: a step-by-step progression
| Stage | Goal | What to do |
|---|---|---|
| 1. Learn the movements | Technique in the basic patterns | Squat, hip hinge, pushes and pulls with bodyweight, a stick or very light loads |
| 2. Light loads | Repeat well with some resistance | Sets of 10-15 reps well short of failure, 2-3 days a week |
| 3. Gradual progression | Gain strength without losing technique | Add weight little by little once every rep is clean |
| 4. Heavy loads | Maximal strength, if the sport calls for it | Sets of 6-8 reps with a coach correcting in real time |
The stage 1 movements are the same ones we explain in the 5 basic strength movement patterns, and the logic of adding load little by little is that of progressive overload. If there is no gym nearby, calisthenics for beginners is a very good way in.
Signs of a good coach (and a bad one)
- Good: corrects technique before adding weight, adapts the load to each youngster and keeps an eye on who is in the room.
- Bad: runs “who can lift the most” contests with beginners or copies an adult bodybuilder's routine.
Common mistakes
- Chasing a max too early: strength in young people improves with consistency, not one-rep records.
- Training alone at home without supervision: it is where most hand and foot accidents happen.
- Forgetting about sleep: teenagers need more sleep than adults to recover, as we explain in sleep and athletic performance.
- Focusing only on muscle: coordination, jumping and speed also improve, and they are often more motivating.
Progrevia is designed for people aged 16 and over. If you are 16 or 17, the generator suggests a routine with loads and progression matched to your level; for the first few weeks, ask someone experienced to check your technique. Below that age, the routine should be designed and supervised by a professional. And for the typical mistakes any beginner makes, see the 12 most common gym mistakes.
- Malina RM. Weight training in youth-growth, maturation, and safety: an evidence-based review. Clinical Journal of Sport Medicine. 2006;16(6):478-487.
- Myer GD, Quatman CE, Khoury J, Wall EJ, Hewett TE. Youth versus adult "weightlifting" injuries presenting to United States emergency rooms: accidental versus nonaccidental injury mechanisms. Journal of Strength and Conditioning Research. 2009;23(7):2054-2060.
- Behringer M, Vom Heede A, Yue Z, Mester J. Effects of resistance training in children and adolescents: a meta-analysis. Pediatrics. 2010;126(5):e1199-e1210.
- Lesinski M, Prieske O, Granacher U. Effects and dose-response relationships of resistance training on physical performance in youth athletes: a systematic review and meta-analysis. British Journal of Sports Medicine. 2016;50(13):781-795.
- Lloyd RS, Faigenbaum AD, Stone MH, et al. Position statement on youth resistance training: the 2014 International Consensus. British Journal of Sports Medicine. 2014;48(7):498-505.
- Faigenbaum AD, Kraemer WJ, Blimkie CJ, et al. Youth resistance training: updated position statement paper from the National Strength and Conditioning Association. Journal of Strength and Conditioning Research. 2009;23(5 Suppl):S60-S79.
- Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine. 2020;54(24):1451-1462.
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Frequently asked questions
At what age can you start lifting weights?
The studies reviewed by Malina (2006) included children in the early stages of puberty, with supervised programmes that did not affect growth. More than a specific age, what matters is that the youngster can follow technique instructions and that someone supervises.
Is it true that weights make you short?
No. In the 22 experimental studies reviewed by Malina, weight-training programmes did not affect the height or weight of the participants. Growth plate injuries are associated with accidents and very poor technique.
Are teenagers injured more than adults when lifting?
Not because of the effort itself. In Myer's study (2009), sprains and strains increased with age, while injuries in the youngest were mostly accidents from dropped weights, preventable with supervision.
How many days a week should a teenager do strength training?
Most of the programmes studied used 2 or 3 days a week. That is a good benchmark to start with, alongside the WHO recommendation of an average of 60 minutes of physical activity a day.
Can a teenager use the Progrevia generator?
Progrevia is designed for people aged 16 and over. At 16 or 17 you can use the generator, asking someone experienced to check your technique for the first few weeks. Below that age, the routine should be designed and supervised by a professional.
Informational content based on the available scientific evidence: it does not replace advice from a healthcare professional. If you have an injury or a medical condition, or are pregnant, check with one before changing your training or diet.
