Does lifting weights affect the growth in teenagers?

Teenagers are often attracted to bodybuilding. That's not surprising: pubescence is the age when good looks and physical attraction become hugely important for almost every young man.

I started with resistance training in my school gym when I was 14. That was unfortunately a long time ago but I remember well all the mistakes I made and all the injuries I (and my friends) brought upon myself.

I also remember how concerned my parents were – they were sure I'm going to get seriously overtrained, especially considering that I combined heavy resistance training with Karate and long-distance running.

In my case they were probably right although I didn't experience the “real” signs of overtraining which can be quite serious.

Parents, teachers and even coaches often caution teens against lifting heavy weights citing growth arrest as the main possible side-effect.

So let's check the scientific sources and let's see if such fears are legitimate or not. But first, let me explain the mechanism of growth in humans and how can physical exercise influence it.

Epiphyseal plate – the key to bone growth

Long bones in children are quite different in their structure from the long bones in adults. The adult bone has two main parts: diaphysis (the long midsection of the bone) and epiphysis (the rounded end on both sides of the long bone).

In growing children and teenagers, there is a third part between epiphysis and diaphysis called epiphyseal plate. Also called physis or growth plate, epiphyseal plate is a cartilage constantly producing new cells called chondrocytes which later ossify – meaning they become part of the long bone.

The growth plates ossify completely after reaching maturity (which is quite individual, usually between 19 and 21 years of age). Complete ossification means that the cartilage becomes part of the bone and only a thin line remains at the border of growth plate and epiphysis, called epiphyseal line.

Epiphyseal plate injury

Now you know what is epiphyseal plate (or growth plate) and how important it is for the bone growth in childhood and adolescence.

But what happens if it gets injured – broken, crushed, displaced – and what will happen to the affected bone?

The possibility of epiphyseal plate injury is exactly the reason why some doctors discouraged heavy exercise in children and teenagers. So forget the “more energy/nutrition going to exercise and less for the growth” nonsense. The only reason why scientists, medical professionals and coaches were cautioning young people against resistance training was the perceived risk of damaging the growth plates.

Epiphyseal plates can really get damaged in training-related accidents. Such accidents are not common but they definitely do exist. Of course, every accident causing broken bone can also cause growth plate injury. From this perspective, skiing or climbing trees are just as dangerous activities as weight lifting.

Some 85% of growth plate injuries will heal with no lasting effects. The remaining 15% will cause deformities in the affected bone: it will either stop growing or it will grow incorrectly and get more-or-less crooked.

In other words, person with growth plate injury can end up with one leg or arm shorter than the other.

It is important to notice that some epiphyseal plates are responsible for much more growth than others. The most active ones are those near the knee. Therefore, serious injuries in the knee area must be avoided at all costs during childhood and pubescence.

The Faigenbaum position statement and other studies

Probably the most complete and most serious modern work on teen bodybuilding is the “Youth resistance training: position statement paper and literature review” by A.D. Faigenbaum and 10 other authors, all of them leading medical authorities. The paper has been written in 1996 and updated in 2009.

Authors are specifically touching the topic of possible growth problems in young people involved in heavy resistance training.

The paper says that “a few retrospective case reports have noted epiphyseal plate fractures during adolescence, however, most of these injuries were due to:

1. improper lifting techniques

2. maximal lifts

3. lack of qualified adult supervision”

(Numbering added by musqle.com).

The paper says clearly and repeatedly that well designed and properly supervised resistance training is beneficial and safe for children and youth.

It also explains that epiphyseal plates are actually stronger in younger children than in teenagers.

Another important study, “Canadian Society for Exercise Physiology position paper: resistance training in children and adolescents” confirms the positive effects of resistance exercises and states in its opening that “Many position stands and review papers have refuted the myths associated with resistance training in children and adolescents. With proper training methods, RT for children and adolescents can be relatively safe and improve overall heath”.