During puberty, the bones are growing rapidly. Growth occurs in the long bones in regions at the ends of the bone called the epiphyseal growth plate. The area of bone just beneath the growth plate is not solid bone and is susceptible to damage. Weightlifting could damage the growth plate and result in stunting of bone growth. For this reason, kids should not begin weightlifting until after puberty, when their bones are no longer growing.
There is no evidence that weightlifting with proper supervision is unsafe for kids.
- Activities such as soccer, skateboarding, and just about any other youth sport result in far more injuries to young bones than weightlifting.
- An analysis published in the Journal of Strength and Conditioning Research of resistance-training injuries that resulted in visits to U.S. emergency rooms demonstrated that children have lower risk of resistance-training-related injuries than adults.
- A study conducted at the University of Pennsylvania in Philadelphia concluded that strength training is safe for kids is consistent with data from the medical literature.
Weightlifting appears to be safe for children with proper supervision.
I received my first weight set when I was 8 years old. It was one of those DP sets that had plastic weights filled with cement. I began then and have continued training for the past 40 years. True to the literature, I did not really begin to experience injuries until I was in my 20s and pushing heavier weight. If you have a son, little brother, or other young family member who wants to start training, the evidence says its OK as long as they are taught proper lifting techniques and are supervised in order to avoid horseplay.