That is an image of Naomi Kutin at 10 years old weighing in at 44kg (97lb) breaking the world record for her division with a 97.7kg (215lb) squat.
Recently, I was in a long car ride with a power lifter who told me she felt children shouldn’t be lifting weights until they are 16. Surprised at her position, I asked why. She reported that weight lifting can injure the growth plates in bones and that they might try to lift more than they can handle.
Ladies and gentlemen, weight lifting does not injure the epiphyseal growth plates in bones. Weightlifting increases rates of ossification thus preventing fractures (Brukner and Khan, Clinical Sports Medicine, 3rd). This is not to say that a damaged growth plate is not possible but simply rare. Let’s look at some basic numbers.
It is estimated by the Centre for Disease Control that 35 million children 0-19 play some form of organized sport each year in the US. 2.6 million will visit a hospital ER, medical clinic, local GP or so other registered medical expert over the course of the year for a sports related injury. Straight up, 7.4% are getting some type of injury serious enough to merit medical treatment. Now, according to my pediatrics book- Staheli, Lynn, Fundamentals of Pediatric Orthopedics 3rd- 15% of all pediatric visits to a hospital are for fractures. I couldn’t find any data specifically on how many are caused by sports or recreation. Let’s hike it up to 25% and say one in four visits are for some type of fracture. So now, of 7.4% we get 1.85% of all kids get some type of fracture. This doesn’t mean a fracture in a growth plate- simply some kind of fracture. This could be a greenstick, a buckle, a hairline or a complex fracture- it’s not relevant to our discussion. How many fractures involve the growth plates? According to Mirtz et al 2011, 10% of sports fractures among youth have some epiphyseal component. So 10% of 1.85% is 0.185%! So the chances that playing any sport will lead to an injury that will affect the epiphyseal growth plate of a child is 0.185% (more or less). I’d like to point out that 1% of sports playing youth or 350,000 children receive a head injury every year and 0.1% will be hospitalized from that injury.
So let’s compare for a moment- most parents have no qualms about putting their kids in soccer, football, baseball or hockey. Despite the fact that they have a 7.4% chance of some form of injury requiring a trip to the hospital. They don’t mind placing them in sports that have some degree of hard head contact (either with players or an object) that has a 1% of causing a concussion and a 0.1% chance of hospitalizing them. The hypothetical threat that weightlifting will cause a fracture in the growth plate (and why weightlifting and not ANY other sport that can also cause a fracture is some mystery) is around 0.185%. So if you are willing to put your kid into any contact sport- you should be willing to send them to a weight room. You can see the Canadian Society of Exercise Physiology’s position on youth and weight training here. You can see a related study here.
Now, in terms of over-loading bones, the other argument the lady used. How old are children when they enter gymnastics? Generally, somewhere between 18 months and 4 years and just to have some numbers- I’m calling it 3 years old. According to the CDC a 3 year old boy weighs 31lb. Now, in gymnastics (or figure skating, cheerleading, dance aerobics, parkour, or any other acrobatic skill) leaping and jumping are involved. The average front flip time from a raised platform (to give the body more time to rotate, as beginners would need) is 0.7 sec. Given that gravity is accelerating a body at 9.81ms/s^2, in 0.7 sec that 31lb (14.09kg) boy hits the ground with 96.76kg or 212.87lb of force. Now, no one thinks twice about putting a young child in gymnastics or another acrobatic skill based program. If asked to load that 31lb child with a 45lb barbell, most parents would gasp when clearly, their skeletons can more than handle the load.
I hope this has helped explain why our position is that weightlifting is safe for children assuming their form is spotted and they are coached well (just like in ANY OTHER SPORT).