“That resistance training will stunt growth in children, or anyone not finished growing”
This has been a major problem surrounding resistance training for as long as anyone can seem to remember. I have no idea where it began, but even today you constantly hear of and meet people that believe this.
Before I get started, some background information on how we grow: There are different classifications for different types of bones in our body, but the majority of them are classified as ‘long’ bones, and these are the bones which will have the greatest effect on our height. Our bones begin as simple cartilage models which later will be transformed into bone, this process is called ossification (the formation of bone). Most of this ossification will occur before or shortly after birth, and for the next 18-23 years your bones will continue to develop and grow.
Bone can grow in a number of ways, appositional growth and endochondral growth being the primary ways affecting height. In ‘long’ bones it is endochondral growth which will determine the length of a bone, which inevitably effects a persons height. At both ends of a long bone there is an epiphyseal plate, which is a layer of cartilage separating the epiphysis (end) from the diaphysis (shaft). This epiphyseal plate is what allows the bone to grow in length (endochondrial growth). This layer of cartilage is continuously growing and expanding, as new cartilage is formed nearest the diaphysis the old cells are ossified (turned to bone), and this process is what makes our long bones grow.
The two main effectors of bone growth are nutrition and hormones. Nutrition is important for providing your body with the necessary energy, nutrients, vitamins and minerals to continue growing. In times of illness or malnutrition children can show signs of arrested growth, which is a line of increased bone density caused by a period of slow growth. Hormones are obviously vital for bone growth, growth hormone, thyroid hormone, and sex hormones are all vital for normal bone growth, these hormones can also be effected by diet. Females tend to stop growing earlier than males due to an increase in estrogen levels. Bone growth will cease when the epiphyseal plate becomes completely ossified.
Now if you happen to fracture a long bone at a young age then there could be some complications, especially if the fracture occurs at the epiphyseal plate. A break at the epiphyseal plate will result in damage to the cartilage which can interfere with the growth of that particular bone. These injuries are quite common amongst children and often result in one arm or leg being shorter than the other. This can largely impact the entire balance of a persons body and distort the positioning of their back, all leading to possible future difficulties. Especially those spinal related.
Back on topic. Now the forces generated with heavy weight lifting can be enormous, but it is highly unlikely that these pressures will have any significant effect on bone growth at all. If you do plan on avoiding resistance training for these reasons then it would be advised that you avoid physical activities all together, since the forces generated in jumping or running can be far greater than those of resistance training.
There are no studies or evidence what so ever that show resistance training to have any effect on height, though many people still believe this myth without question. One common argument is the size of professional weightlifters, who are generally all of very short stature. This has nothing to do with their weightlifting or training, rather the process of natural selection. A 5”1 80kg person would have a large advantage over a 5”10 80kg person when it comes to professional powelifting. Why? Because the shorter person has much shorter levers, meaning they can generate more power and need to move the weight a shorter distance. These people are not short because they are professional weightlifter, they are professional weightlifters because they are short.
In my opinion resistance training is often a great way to encourage growth when performed correctly, because participants are often interested in getting their diet and lifestyle in order aswell. If they do the proper research then I think they will have the knowledge to live a healthy lifestyle and grow to their fullest potential. It is sports like dancing, gymnastics and wrestling which can have a negative impact on height. This is due to the weight categories and calorie restricted diets put in place to encourage these athletes to stay small and light, which can have a huge impact on their development.
