Like CrossFit, mentioning this topic in a group of health and fitness professionals is sure to start a heated debate: 1) because it involves a sensitive group of the population, and 2) because most of what these professionals “know” is hearsay. I’m here to put the debate to rest and to address some common miss-conceptions.
Closing of growth plates
This is usually the number one argument for those that oppose introducing weight-training for children and youth: True of Flase? Weight training, at too young of an age, will close the individuals growth-plates, dooming them to a life of T-Rex arms and midgetry.
Well, this one actually turns out to be true and false. Because of bodies that are in a constant state of flux, children and adolescents are more at risk for epiphyseal plate fractures, which can in fact stunt their growth due to injuries occurring at a time in their life when growth-rate is at its peak. However, studies have shown that safe weight-training, under proper instruction, can actually improve a youth’s strength by 30-50% in as little as 8 to 12 weeks, with no negative impact to their ultimate height.
They’re doing it anyways
The fact is, if a child is playing sports, they are going to be exposed to forces that are stressful to their body anyways. This is one major argument for starting weight training at a young age. At least in a gym setting, the individual can strengthen their body, under controlled circumstances, in vulnerable positions. Studies have shown that while advanced plyometric training, like weighted jump squats and 32 inch drop box jumps may NOT be safe for youth, early adolescence may be the optimal time to introduce body weight variations on plyometric movements, because this is the age that neurological adaptation is most autoplastic, potentiating greater athletic performance later in life.
These findings suggest that weight training, in a controlled and safe environment, is actually beneficial to children and youth. What should be avoided is substantial overload (like power lifting) and ballistic movements with heavy weight (like Olympic lifting) as these activities offer a higher propensity for injury in a developing body. Other limitations the American Academy of Pediatrics (AAP) suggest is avoiding repetitive maximal lifts (lifts that are one repetition maximum lifts or are within 2-3 repetitions of a one repetition maximum lift) until they have reached Tanner Stage 5 of developmental maturity. Tanner Stage 5 is the level in which visible secondary sex characteristics have been developed. Usually, in this stage adolescents will also have passed their period of maximal velocity of height growth.
So, what age CAN they start lifting then?
Most research has been performed on children no less than 8 years old, however researchers agree that calisthenics (body weight only exercises, like push-ups) can be safely introduced at any point. If children or adolescents undertake a strength training program, they should begin with low-resistance exercises until proper technique is learned. When 8 to 15 repetitions can be performed, it is reasonable to add weight in small increments. Exercises should include all muscle groups and be performed through the full range of motion at each joint, though never to failure. To achieve gains in strength, workouts need to be at least 20 to 30 minutes long, take place a minimum of 2 to 3 times per week, and continue to add weight or repetitions as strength improves. There is no additional benefit to strength training more than 4 times per week. When a child has reached puberty (13 for girls, 15 for boys) they can then begin a more advanced, carefully periodized program.