By Andrew Cochran, PhD, CSCS

“Is it safe for my young athlete(s) to weight train?” This is a question I hear often.  I hear it from sport coaches, from athletes’ parents, and from friends who are new to parenthood but are already drafting their newborn’s professional contract(s).

While almost certainly “preaching to the choir” on this one, I think it’s important to provide a succinct and well-educated response to this question.  Not only because it’s my job, but also because it a) helps educate coaches’ and parents to make the best health & performance decisions possible, and b) (hopefully) helps curb the spread of misinformation that I constantly battle within our industry.  Therefore, it’s my goal with this article to help provide readers with relatively straightforward responses to some common questions surrounding youth resistance training. 

First, some definitions: For the purposes of this article, “youth” will refer to anyone below the age of 18, that is to say, high school age, as this is the focus of the CSCA Spring Newsletter.  Beneath the youth umbrella, “childhood” is considered up to the age of 11 for girls and 13 for boys, and “adolescence” is the balance of those athletes’ years up to the age of 18 (i.e. 12-18 for females, 14-18 for males).  “Resistance training” (RT) is also defined as “the progressive use of resistive loads to enhance health, fitness and sports performance” and includes all resistance modalities including body weight, elastic bands, weight machines, med balls, and of course, free weights (1-2).

1. Is it safe for my young athletes to weight train? Yes. Provided…

a) They are supervised by a qualified professional who possesses a recognized and relevant certification (i.e. NSCA CSCS, UKSCA ASCC, or ASCA Level 1 or greater) and has knowledge of pediatric exercise physiology

b) Programs are designed in accordance with the needs, goals and competency/abilities of the athletes

c) The priority is appropriate movement mechanics and lifting technique, with logical and methodical training progressions (e.g. Acute to Chronic Workload Ratios) based on individual abilities, biological age, and training experience

Allow me to elaborate: Since 2000, there have been no fewer than 7 position papers published on youth resistance training, and ALL of these have concluded that RT is safe for children and adolescents when supervised by a qualified professional. These position stands have come not just from organizations such as the Australian Strength and Conditioning Association (3), National Strength and Conditioning Association (2), and UK Strength and Conditioning Association (4), but also the Canadian Society for Exercise Physiology (5), British Association of Exercise and Sports Sciences (6), and importantly, the American Academy of Pediatrics (7).  The evidence has been so strong that, in 2014, an International Consensus Statement supporting youth resistance training was published (1; PMID:24055781 DOI:10.1136/bjsports-2013-092952). This statement was endorsed not only by the same organizations listed above, but also by the American Medical Society for Sports Medicine (AMSSM), the North American Society for Pediatric Exercise Medicine (NASPEM), the Faculty of Sport and Exercise Medicine UK (FSEM), and the National Athletic Trainers’ Association (NATA), to name a few.  Safe to say, most experts in our field would agree that RT is safe for youth athletes.

While this answer may be enough, more specific questions pertaining to this topic may be asked.  For example:

2. Will resistance training stunt my kids’ growth?

No. It won’t (provided above criteria are met).  It will build bone density and structure.

This concern arises from the idea that RT may cause injuries (e.g. fractures) within the growth cartilage of young athletes, thus resulting in a reduction in linear growth.  Indeed, there is evidence to show that the growth plate can be 3-5x weaker than surrounding connective tissue, and it may be less resistant to shear and tension forces (8).  However, there have been no reports of injuries to the growth cartilage in any prospective study of youth RT when professional supervision has been provided (8).  In the words of the experts in the International Consensus: “Fears that resistance training would injure the growth plates of youths are not supported by scientific papers or clinical observations” (1).  Furthermore, “traditional fears and misinformed concerns that resistance training would be harmful to the developing skeleton have been replaced by reports indicating that childhood may be the opportune time to build bone mass and enhance bone structure.” (1). 

3. What about resistance training causing other injuries?

In reality, the injury risks are likely lower in resistance training than they are in [insert sport here].  In fact, resistance training is one of the best ways to prevent injuries (see question 4 below).

Sport-related injuries are, unfortunately, somewhat of an inevitability if the athlete trains frequently/hard enough (not that we don’t do our best to prevent them).  These injuries can arise from a variety of sources both intrinsic (e.g. prior injury, growth rates, anatomic alignment, biomechanics, etc.) and extrinsic (e.g. workload, scheduling, equipment) (9).  The question is, does RT cause or increase the rate of these injuries?  The short answer, again, is no.  The vast majority of supervised, prospective RT studies in youth have reported very low or nil injury rates, and for those injuries that have been reported, most acute injuries occur when the youth are unsupervised (or supervised by unqualified personnel) (8).  In fact, Myer et al. (10) reported that ~77% of all resistance training-related injuries in 8-13 year old athletes were accidental (e.g. “dropping” or “pinching”), and potentially avoidable with proper supervision.

Another valuable way of examining RT injury rates is by placing them within the context of other sports.  Resistance training injury rates in adults have been placed at an average of ~2-4 injuries per 1000 h of participation (11).  This is inclusive of powerlifting and weightlifting, and appear to hold true for youth athletes as well (8).  Comparatively, one 2008 epidemiological review showed that injury rates for boys were the highest for ice hockey (5-34.4 injuries/1000 h), Rugby (3.4-13.3 Injuries/1000 h), and soccer (2.3-7.9 Injuries/1000 h), while for girls it was soccer (2.5-10.6), basketball (3.6-4.1), and gymnastics (8.5) (12).  Interestingly, running alone seems to have one of the highest rates of injury for any sport. Videbaek et al. (13) reported weighted injury rates of 16.7-19.1 injuries/1000 h for adult novice runners, and 6.9-8.7 for recreational runners through meta-analytic analysis.  What’s also interesting is that, for youth athletes, if you change the metric from injuries per 1000 h of activity to “injuries per athlete exposure”, (cross-country) running jumps to the top of the list for both girls and boys (12).  Yet, no one seems to be telling young athletes to avoid running.  The fact is that, with professional guidance, resistance training will likely prevent injuries, not cause them.

4. Will resistance training even do anything for a kid? Will it make that big of a difference?

Yes, resistance training in youth can make a big difference in two areas:

a) Performance: Resistance training can induce many of the same performance-enhancing benefits in youth as it can in adults.  Specifically, it has been shown that resistance training can increase strength (14), power, running velocity (15), change of direction ability, and general motor performance (1, 16).  Youth are also bound by the principle of disuse/reversibility in that they must “use it or lose it” (1), therefore training must be consistent if they wish to maintain these benefits.

b)Injury Prevention: This could arguably be the more important role of resistance training in youth athletes.  Logical and methodical resistance training progression can help enhance bone mineral density, create larger margins of safety for soft tissue against both acute and overuse injuries (17).  In fact, it has been shown that resistance training may reduce overall injury risk by 68%, and overuse injuries by as much as 50% (18-19). What makes this especially significant is the fact that one of the biggest predictors of overuse injury in youth is prior injury (9). 

“Putting the cart before the horse”?

The current approach in youth sport is generally something like this: enroll in the sport, play more, and more, and more, and even more, and then maybe, if the athlete is good enough, resistance training may be a consideration to help move them to the “next level”.  Most parents/coaches never consider whether (or not) the athlete is physically prepared to produce or withstand the forces that will be encountered in the sport.  For instance, basic jumping and landing activities in sport expose athletes to ground reaction forces in the vicinity of 5-7 times body weight (1).  Not only are these ground reaction forces in excess of what they would generally encounter in the weight room, but they also experience them in a much less controlled or predictable fashion.  Further compounding this issue is the fact that youth sport is continually increasing in its professionalization and specialization (e.g. more practices, more competitions, year-round specialization at younger and younger ages), while the habitual levels of strength and activity are trending downwards (1).  The result is a greater discrepancy between the demands of youth sport and the preparedness of the athletes who are enrolling in them.  Couple this with the tendency for youth coaches to try to emulate the practices/workloads of elite athletes earlier and earlier, the seemingly inevitable result will be higher youth injury rates. 

Therefore, in my opinion, this perspective of the sport first, resistance training second really puts the “cart before the horse”.  Given the facts that RT is “safer” than most sports, can increase performance and reduce injury risk within those sports, while having no negative effect whatsoever on growth, I consider supervised and year-round progressive resistance training be considered foundational for youth preparation for competitive sport. 

5. How young is too young?

There really isn’t an age restriction, provided the resistance training program is designed appropriately and tailored to the child’s individual abilities.  Research has shown positive benefits of RT in children as young as 5-6 years of age (1).

Remember that RT encompasses all forms of resistance, including bodyweight. Learning to walk is “resistance training”, every time we need to overcome our own body weight to stand up and make the transition from quadrupedal to bipedal ambulation.  We would never hold anyone back from learning to walk just in case they might get hurt (kids are falling all over the place), so provided we are logical in our progressions, why wouldn’t we add a little more challenge once things become easy for us?  This might be an extreme example, but the premise is sound.  Given the appropriate time to adapt and recover, our bodies can withstand and benefit from added loading.  Granted, common sense needs to be implemented here and, as with all things, moderation is likely the best path, but provided there is qualified supervision and proper technique, any age can be the “appropriate” one for RT.

Take-Home Points:

1. Resistance Training is safe for children and adolescent athletes of nearly all ages provided they are working with and instructed by a qualified professional
2. Resistance Training will not stunt growth, and injury rates are in most cases lower than the sports they are playing (again, with appropriate supervision and programming)
3. Resistance Training imparts many of the same performance and injury prevention benefits for youth as it does for adult athletes; they are also bound by the “use it or lose it” principle, so consistency is key.
4. Resistance Training should be considered a foundational element in the proper preparation of youth for competitive sport rather than an “add-on” once they’ve reached a certain competitive level.

Author Biography

Andrew Cochran completed his PhD in exercise physiology, with a specialization in sport nutrition, at McMaster University in 2013.  Since that time, he has been employed as both a Sport Physiologist and Strength & Conditioning Coach at the Canadian Sport Institute Ontario.  Here he works primarily with developmental and “NextGen” athletes in the sports of Beach Volleyball and Diving ranging between the ages of 14 and 30. 

References

1) Lloyd, R.S., et al. Position statement on youth resistance training: the 2014 International Consensus. Br J Sports Med 2013; 0: 1-12.

2) Faigenbaum, A.D., Kraemer, W.J., Blimkie, C.J., et al. Youth resistance training: updated position statement paper from the National Strength & Conditioning Association. J Strength Cond Res 2009; 23: S60-79.

3) Baker, D., Mitchell, J., Boyle, D. et al. Resistance training for adolescents and youth: a position stand by the Australian Strength and Conditioning Association (ASCA). 2007 https://www.strengthandconditioning.org

4) Lloyd, R.S. Faigenbaum, A.D., Myer, G.D. et al. UKSCA position statement: youth resistance training. Prof Strength Cond J 2012; 26: 26-39.

5) Behm, D.G., Faigenbaum, A.D., Falk, B., and Klentrou, P. Canadian Society for Exercise Physiology position paper: resistance training in children and adolescents. Appl Physiol Nutr Metab 2008; 33: 547-561.

6) Stratton, G., Jones, M., Fox, K.R. et al. BASES position statement on guidelines for resistance exercise in young people. J Sports Sci 2004; 22: 4, 383-390.

7) American Academy of Pediatrics. Strength training by children and adolescents. Pediatrics 2008; 121: 835-840.

8) Faigenbaum, A.D., Myer, G.D. Resistance training among young athletes: safety, efficacy, and injury prevention effects. Br J Sports Med 2010; 44: 56-63.

9) DiFiori, J.P., Benjamin, H.J., Brenner, J.S., et al. Overuse and burnout in youth sports: a position statement from the American Medical Society for Sports Medicine. Br J Sports Med 2014; 48: 287-288.

10) Myer, G.D., Quatman, C.E. Khoury, J. et al. Youth vs. adult weightlifting injuries presenting to United States emergency rooms: accidental vs. non-accidental injury mechanisms. J Strength Cond Res 2009; 23: 2054-60.

11) Keogh, J.W.L., Winwood, P.W. The epidemiology of injuries across the weight-training sports. Sports Med 2017; 47: 479-501.

12) Caine, D., Maffuli, N., Caine, C. Epidemiology of injury in child and adolescent sports: injury rates, risk factors, and prevention. Clin Sports Med 2008; 27: 19-50.

13) Videbaek, S., Bueno, A.M., Nielsen, R.O., Rasmussen, S. Incidence of running-related injuries per 1000 h of running in different types of runners: a systematic review and meta-analysis. Sports Med 2015; 45: 1017-1026. 

14) Behringer, M., vom Heede, A., Yue, Z et al. Effects of resistance training in children & adolescence: a meta-analysis. Pediatrics 2010; 126: 1199-2010.

15) Sander, A., Keiner, M., Wirth, K., Schmidtbleicher, D. Influence of a 2-year strength training programme on power performance in elite youth soccer players. Eur J Sport Sci; 2012: 13(5): 445-51.

16) Behringer, M., vom Heede, A., Matthews, M. et al. Effects of strength training on motor performance skills in children and adolescents: a meta-analysis. Pediatric Exercise Science 2011; 23: 186-206.

17) McGill, S. The biomechanics of low back injury: implications on current practice in industry and the clinic. J Biomech 1997; 30: 465-475.

18) Lauersen, J.B., Bertelsen, D.M., Andersen, L.B. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomized controlled trials. Br J Sports Med 2014; 48: 871-877.

19) Zwolski, C., Quatman-Yates, C., & Paterno, M. V. (2017). Resistance Training in Youth: Laying the Foundation for Injury Prevention and Physical Literacy. Sports Health, 9(5), 436–443.