Fort Worth, Texas,
14:45 PM

A weighty issue: Strength training and kids

A physical therapist gives the facts (and myths) of kids and weight training

Should our kids be lifting weights?

You may have seen articles and video clips in the news lately discussing whether kids should be lifting weight.

“Is it safe?” “How much weight is too much?” “What is the injury risk?”

The longstanding belief has been that strength training could cause damage to the growth plates (or epiphyseal plates) in bones, but recent research is beginning to shift that thought. There’s even a book that’s recently been published by a famous Jeopardy contestant advocating for the importance of strength training in kids as it promotes healthy bone density and body composition as well as improved overall fitness and may even aid in injury prevention.

On paper, that sounds great! With childhood obesity rates continuing to rise, shouldn’t we be doing everything possible to make our kids healthier?

Let’s look at this from a few different angles…

First of all, physical therapists, physicians, athletic trainers and most clinicians are familiar with something known as the SAID principle. This principle states that when stressors or loads are applied on the body, there is a Specific Adaptation to Imposed Demands (SAID) that occurs over time.

And what does that mean? Basically, if you do an activity over and over again, your body will change to adapt to the activity.

For example, a baseball pitcher will have noticeable differences in muscle mass and range of motion in his throwing arm vs. his opposite side. Just as a marathon runner in the peak of season will have heightened endurance for long distance running but would most likely struggle with sprinting.

In the same way, if you spend long amounts of time in front of a computer screen, watching TV, or playing video games, your body and posture will adapt to that positioning over time. So if we can promote improved strength and cause positive changes in the body as kids are growing, why shouldn’t we be encouraging weight training?

Common strength training myths:




I cannot emphasize this point enough. When a new patient comes into the clinic, before I even bring them back, I like to create a picture in my head of what is going on. “Why does their back hurt?” “Why did they tear their ACL?” “Why do they keep spraining their ankle?”

It seems that 99.9 percent of the time, their problems can be traced back to not being taught proper form and never developing correct mechanics. It never ceases to amaze me when a high school athlete tells me he back squats almost double his body weight, yet when I ask him to show me a squat without weight, he has no core control, hip weakness causing poor knee alignment, and a complete lack of calf flexibility (among other things).

I cringe when I think of what he looks like with weight added. Then there’s the junior high athlete telling me he’s working on bench press, yet his core control is almost completely absent. And let’s not forget the adolescent girl who struggles to control her knee position when she stands up from a chair, but then is working on weighted squats and lunges as part of her off season training.

When we look at proper training, we should be teaching our kids how to recruit the appropriate muscles first before we ever add any resistance. Learning proper muscle recruitment and training the correct pattern is known as motor learning. Studies show that there’s a strong window of opportunity for this between the ages of 10 -13, but that doesn’t mean it’s not something that can’t be addressed at any age.

Show me a proper squat, lunge, bench press, dead lift … with good form repetitively before any weight is added. If you can’t do that, adding weight is only going to encourage bad habits and increase injury risks (just as the SAID principle states). How often do we hear stories of high school or college athletes who appear “strong” yet a simple direction change, and they fall to the ground and end up with a torn ACL?

What does the American Academy of Pediatrics say?
  • Strength training programs for preadolescents and adolescents can be safe and effective if proper resistance training techniques and safety precautions are followed.
  • Preadolescents and adolescents should avoid competitive weight lifting, power lifting, body building, and maximal lifts until they reach physical and skeletal maturity.
  • When pediatricians are asked to recommend or evaluate strength training programs for children and adolescents, the following issues should be considered:
    • Before beginning a formal strength training program, a medical evaluation should be performed by a pediatrician. If indicated, a referral may be made to a sports medicine physician who is familiar with various strength training methods as well as risks and benefits in preadolescents and adolescents.
    • Aerobic conditioning should be coupled with resistance training if general health benefits are the goal.
    • Strength training programs should include a warm-up and cool-down component.
    • Specific strength training exercises should be learned initially with no load (resistance). Once the exercise skill has been mastered, incremental loads can be added.
    • Progressive resistance exercise requires successful completion of 8 to 15 repetitions in good form before increasing weight or resistance.
    • A general strengthening program should address all major muscle groups and exercise through the complete range of motion.
    • Any sign of injury or illness from strength training should be evaluated before continuing the exercise in question.

So to summarize… yes, I am all for promoting physical activity in kids. Weight lifting has definite benefits, but it needs to be done in a controlled environment. Kids NEED to be taught how to lift weights correctly. If problems are identified or there is any pain, a referral to an appropriate health care provider like a sports medicine physician or physical therapist is crucial. The earlier that children learn correct motor patterns, the more successful they will be in future sports. And above all, physical activity should be fun.

About the author

Melissa Bro, PT, DPT, SCS, is a physical therapist for the Cook Children's SPORTS Rehab program. Our physicians, therapists, nurses and technologists work exclusively with kids and understand the unique needs of a growing athlete's bones, muscles, body and mind. As a part of Cook Children's integrated pediatric health care system, our patients have access to a multitude of pediatric specialty areas with board certified doctors, as well as laboratory services, nutritional consultations and sports medicine counseling.

Patients benefit from this integrated system because it allows our staff to use all of the system's resources during treatment. It also improves communication between the various departments whose physicians are focused on caring for children and adolescents.

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