Can Lifting Weights Stunt My Child’s Growth

                I teach a kid’s fitness and fun camp.  When I tell parents about that class, one of the questions I often receive (spoken or unspoken) is: Can lifting weights stunt my child’s growth?  Let me do my best to answer that question as clearly as I can.

                There is no evidence that lifting weights can stunt a child’s growth.  I am amazed at how persistent and pervasive this idea is.  I believe this idea came about in the 40’s when weight training was beginning to become more popular.  Keep in mind at that time they also thought that weight lifting would make one slow and unathletic, and now of course almost every high level athlete in every sport engages in some form of resistance training. 

                Science is pretty awesome.  Here’s a list of a few other things that have as much evidence behind them as the idea that lifting weights could stunt a kid’s growth:

Believing that lifting weights can stunt a child’s growth is the same as believing that squeezing grapefruit juice over a pepperoni pizza will dissolve its calories

Believing that lifting weights can stunt a child’s growth is the same as believing the earth is flat

Believing that lifting weights can stunt a child’s growth is the same as believing the pyramids are actually spaceships for aliens

Believing that lifting weights can stunt a child’s growth is the same as believing the fortune teller charging you $50 to tell what the winning lottery numbers will be

But – Growth Plates!

                Here’s a simple scenario that will hopefully drive this point home.  If someone told you that they spent their entire childhood working and growing up on a farm, would you visualize that person as being weak, frail, and small?  Or would you visualize that person as big, strong, and stout?  The body can’t tell the difference between a dumbbell and a bucket of water, or a bale of hay and a barbell, or a wheelbarrow and a cable.  The body simply experiences resistance and then adapts to that resistance to become better able to handle it in the future. 

                I worked with a client who fell off her horse when she was 12.  In the fall she broke her arm and she broke it in such a way that she damaged the growth plate in her forearm.  After that injury her forearm stopping growing and when she was an adult one of her arms was longer than another.  You might initially think this is evidence that you could stunt one’s growth, but it is not. 

                You do not have just one “Growth plate” for your entire body, you have a bunch of them, each one affecting a specific bone.  To stunt your growth – in other words to make one shorter in height than they are genetically intended to be – you would have to damage all of those growth plates simultaneously which simply isn’t going to happen. 

                Is it possible to injure a single growth plate while weight lifting?  Yes, it is possible.  However it is worth noting that while a kid may lift more weight than they might typically encounter in their daily activity, the forces on the bones are much less in weight lifting than they are in almost every other sport because there is very little acceleration and almost no impact in resistance training.  From a safety point of view, it would be completely inconsistent to allow one’s child to play common sports such as soccer, baseball, or basketball, or even participate in gym class (and it is possible to injure a growth plate in those sports as well); and yet not allow that same child to engage in resistance training under the supervision of a qualified instructor.  And even if one did injure a growth plate, that doesn’t mean that now their total height is somehow compromised. 

                I cannot make the claim that resistance training is perfectly safe.  No activity is.  You can fall down the steps at school or bang your head in recess.  It is impossible to remove all dangers from your child’s life.  However upon reflection, hopefully one realizes that is not the goal.  Hopefully one realizes the goal is to properly prepare your kids so they are ready for whatever life might throw at them.  To place in front of them challenges and obstacles; challenges and obstacles that preferably can be graded in intensity and matched to the child’s ability, so that regularly overcoming and defeating these challenges in turn builds a stronger and more resilient individual.  And I would challenge you to find a better and safer activity than weight training to do just that. 

Nine year old lifts 60 lbs overhead for reps!!!

Resources

                If you want some of them fancy smancy science-based references to back up this article, here you go:

National Strength and Conditioning Association Position Statement on Youth Training:

https://www.nsca.com/globalassets/about/position-statements/position_stand_youth_resistance_training—2009.pdf

ACSM Physical Activity and Bone Health Position Statement:

https://journals.lww.com/acsm-msse/Fulltext/2004/11000/Physical_Activity_and_Bone_Health.24.aspx

Strength Training in Children and Adolescents

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445252/

Canadian Society for Exercise Physiology position paper: resistance training in children and adolescents

https://www.ncbi.nlm.nih.gov/pubmed/18461111

Strength training for children and adolescents: what can physicians recommend?h

https://www.ncbi.nlm.nih.gov/pubmed/20086488

Injury Rates for Children in Sports

https://startingstrength.com/article/strength_and_prevention_of_injuries

“No scientific evidence indicates that weight training or forms of sensible exercise will stunt a child’s growth”  NPTI’s Fundamentals of Fitness and Personal Training, pg 430.  Human Kinetics, 2014