Myth 1: It stunts growth
This is the most persistent myth and the least supported. No controlled study has shown that properly supervised resistance training reduces final adult height or damages growth plates. The concern originated from case reports of unsupervised children attempting maximal overhead lifts, a very different activity from a coached programme.
In practice, loading is a stimulus for bone development, not a threat to it. Youth resistance training is consistently associated with improved bone mineral density.
Myth 2: It's more dangerous than sport
Injury rates in supervised youth resistance training are lower than in most competitive team sports. The activity that actually carries risk is a busy match schedule with no physical preparation behind it. Strength training is one of the few interventions repeatedly shown to reduce injury rates in young athletes.
Myth 3: Children will bulk up
Before puberty, children have low circulating anabolic hormones, so strength gains come almost entirely from the nervous system learning to recruit muscle more effectively. A 10-year-old can get significantly stronger with very little visible change in size. Meaningful hypertrophy arrives with puberty, and even then it requires deliberate volume and eating to match.
Myth 4: You must be 14 to start
- Readiness is behavioural, not chronological: can they follow instructions, take coaching and stay safe in a session?
- Most children are ready for structured bodyweight training from around 7–8 years.
- External load can be introduced once movement quality is consistent, often well before 14.
- The risk of starting late is not injury, it is missing years of motor skill development.
Myth 5: Bodyweight only is always safer
Bodyweight is an excellent starting point, but it is not automatically lighter. A single-leg hop or a depth landing places far higher force through a knee than a controlled dumbbell squat. What matters is the load relative to the athlete's current capacity and their ability to control it, not whether the resistance came from a dumbbell or from gravity.
Myth 6: Machines are safer than free weights
Machines are fixed to adult dimensions and rarely fit a young athlete's limb lengths. Well-coached free weight and bodyweight work develops coordination, balance and trunk control that machines cannot. For most young athletes, dumbbells, kettlebells, bands and their own bodyweight are both safer and more useful.
Myth 7: Sport is enough
Playing sport develops sport skill and conditioning, but it does not systematically build the strength qualities that protect tissue. A young footballer may run eight kilometres a week without ever performing a controlled single-leg squat or a heavy calf raise. Sport creates the demand; strength training builds the capacity to meet it.
Myth 8: Lifting heavy is the point
- Progression should come first from technical quality and range, then tempo, then load.
- Sets of 8–15 controlled repetitions cover most youth training needs.
- Maximal testing has little value in developing athletes and adds unnecessary risk.
- The best set is the one that is repeatable with the same quality on the last rep as the first.
Myth 9: Girls shouldn't train the same way
Young female athletes benefit from strength training at least as much as their male peers, and arguably more given the higher rates of ACL injury and patellofemoral pain in adolescent girls. The programme structure is the same; there is no separate, lighter version.
Myth 10: You need supplements
Adolescent athletes need adequate total energy, regular protein-containing meals, and enough calcium and vitamin D for bone development. That is food. Supplements are unnecessary for the vast majority, poorly regulated, and no substitute for eating and sleeping properly.
What actually matters
- Competent supervision and coaching of technique.
- Two to three sessions a week on non-consecutive days.
- Gradual, planned progression rather than week-to-week jumps.
- Enjoyment, a programme a 12-year-old will not do has no benefit at all.