I’m sure you’ve heard it before…“Lifting weights as a kid will stunt your growth!”
This dogma has been passed down as fact for decades with stories retold of “so-and-so” who lifted weights too early and didn’t reach a normal height. Whether this is some type of fear tactic created by parents who didn’t want their kids getting injured in the gym or hanging around “gym rats” and “muscle heads” or if the idea just seemed iron clad enough to go unquestioned, it’s stuck around too long.
No matter how the idea started, let’s set the record straight for good.
Does Weight Training Cause Stunted Growth?
Lifting weights as children or adolescents does NOT stunt growth.
In fact, there hasn’t been a single peer reviewed paper to date showing a direct correlation between lifting weights and stunted growth.
Why Do People Believe Weight Training Stunts Growth?
One of the possible origins for the stunted growth myth comes from case studies (single patient reports) about epiphyseal plate injuries from weight training.
Epiphyseal plates, also called growth plates, are located at the end of long bones in children and adolescents. These plates are where new bone is added to existing bone to add length. Epiphyseal plates are only present up to certain ages, between 12-16 for girls and 14-19 for boys, after which point they fuse and close.
Growth plate injuries can affect new bone development and therefore affect the total length of the bone at the end of maturation. This most often occurs during trauma that causes bone fractures or breaks to occur. In children and adolescents, growth plate injuries are more likely to happen while playing sports versus lifting weights.
Only a handful of case studies have reported on epiphyseal injuries that occurred during weight training. To further combat the myth, many of the growth plate injuries reported from weight lifting occurred at the arm and wrist and therefore had no impact on height.
Additionally, it wasn’t the act of strength training itself that caused the injury, but rather, a lack of proper adult supervision, lifting excessive weight beyond guidelines, or training with poor technique. Growth plate injuries were consistently tied to “user error.” Just because some people are poor drivers and crash their cars doesn’t mean that driving inherently causes injury.
The Benefits of Weight Training Among Youth Athletes
More importantly, there are many articles that show positive health benefits when kids lift weights. These benefits include improved strength, greater range of motion, enhanced sports coordination, improved speed and agility, and decreased injury risk. Plus, it increases bone density, fights obesity, and improves self-esteem. If these benefits are exactly what we want for our youth athletes, then why is strength training marginalized and feared by most parents?
As parents and coaches, we tend to teach the same way we learned as kids. If our parents and coaches told us that strength training stunts growth, then we’re likely to pass on that same belief to our kids. Even without evidence to back it up, the fear that we might cause our kids injury is reason enough to avoid it altogether.
Unfortunately, this type of thinking has robbed children and adolescents of the health benefits of weight lifting. In an effort to keep our kids free from injury we have kept them from one of the best ways to avoid injury!
If you’re still concerned about your child lifting weights, maybe this will help: the American Academy of Pediatrics, the American College of Sports Medicine, the American Orthopaedic Society for Sports Medicine, and the National Strength and Conditioning Association ALL agree that a supervised strength training program is safe and effective for children.
Injury Risk in Sports vs. Weight Lifting
It’s no secret that kids get hurt — if your child is active, it’s more likely a question of “when” rather than “if.” But, if the goal is to keep them as safe as possible and minimize injury risk, it’s worth examining the causes of injury among youth athletes and the various compounding factors.
Causes of Injury in Youth Athletes
If we take a deeper look at growth plate injuries (and injuries in youth sports in general), an interesting picture emerges. The most common cause of growth plate injuries is from falling off playground equipment or household furniture, and beyond that, approximately 33% of injuries are caused by youth sports participation, while 21% are caused by biking, skateboarding, and skiing activities. Weight lifting doesn’t even make the list. Additionally, growth plate injuries are more likely to occur in periods of rapid growth during which kids demonstrate a decrease in coordination that leads to higher injury risk.
It has also been proposed that excessive repetitive loading, such as jumping during gymnastics, leaping in dance, and cutting in soccer, wears down the growth plate over time through stress-related mechanisms. Instead of a single event such as a fracture causing injury, the cumulative hours of training can prove above and beyond the physical limits of youth athletes.
Training Intensity and Specificity
Recently, specialization in sports and intensity of training has increased for children and adolescents. Sports are now played year-round and youth athletes are specializing in one sport versus playing different sports throughout the year.
In an effort to gain an edge, parents sign their kids up for “competition” leagues, travel clubs, and elite training at younger ages than previous generations. It’s not uncommon now to have youth athletes at practice 5 days per week with games on the weekend. In turn, sport specialization has been linked to higher injury risk and eventual burnout at older ages. Without proper breaks, or diversity of sport play, overuse injuries can run rampant.
More coaching, skill practice, and competition is viewed as essential to developing a competitive athlete. Increasingly, youth athletes are practicing more complex skills and more intensive play at younger ages without adequate foundational movement development. This continues through adolescence, magnifying movement deficits as play intensity increase and consequently increasing the risk of injury.
Understanding Loads and Forces in Youth Athletics
Finally, let’s take a look at the actual loads and forces that take place during sport play compared to strength training.
In sports, the actions of jumping, cutting, throwing, and contact with other players is significant. Sprinting, which is a part of nearly every sport, involves loading of 2.5-3x the body weight per step! Conversely, it would be near impossible for youth athletes to lift 2-3x their body weight while strength training.
Additionally, the force applied to muscles and tendons during a deceleration or change of direction action are much greater than forces encountered with strength training. It would be more appropriate, therefore, to have reservations about excessive sport play rather than strength training.
Keys to Safe Lifting for Kids
Now that we have established that strength training is not only safe for youth athletes but, when applied correctly, likely to decrease their injury risk, let’s take a look at how to strength train correctly at a young age.
Require Adult Supervision
First and foremost, ALL youth athletes need to be supervised by an adult when strength training. Adults can ensure that athletes are following safe lifting guidelines applicable to lifters of all ages, such as racking weights, setting machines at the correct alignments, taking proper rest breaks, and keeping lifting areas clear of clutter and people. Adults can also be there to keep more competitive athletes from trying to win bragging rights by lifting weight beyond their capabilities (yes, adults do this too).
Incorporate a Variety of Exercises
Youth athletes should use a variety of training styles. Free weights, machines, balance devices such as Bosu balls and Dynadiscs, Pilates, and light plyometrics are ideal. By using a variety of training styles, children can develop more complex and well-rounded functional movement patterns that are more transferable to sports. Plus, altering training styles is exciting and fun, reducing the likelihood of burnout or complacency in movement.
Maintain Sound Technique
Proper strength training technique is also essential for youth athletes. This starts with doing bodyweight drills and mastering ideal form. Once an athlete can pass certain benchmark tests like push-ups, sit-ups, squatting with a training stick, and jumping, they can move on to free weights and complex lifts.
Submaximal loads are ideal for training quality of movement over quantity of weight lifted. Youth athletes should avoid one repetition maximum lifts until skeletally mature. Although no studies have shown injury with maximal lifts, the testing procedure is often not followed and there is a high risk for form breakdown.
In terms of frequency, children will see benefits from strength training at two workouts per week. Consistency is key for seeing strength training benefits, but not every exercise needs to be incorporated in each session. Aim for two sessions a week and mix and match the training styles outlined above to keep the program engaging and challenge the athletes.
Implementing a Youth Weight Lifting Program
Programs should be designed to create a strong foundation for youth athletes to build on in later sports training. Each program should incorporate the key elements described above, as well as emphasizing functional movement patterns.
The Importance of Functional Movement Patterns
Children have fewer opportunities than in previous generations to climb trees, play pickup sports, or build forts due to the increased push for organized sports and events. These childhood rights of passage serve a vital purpose in providing kids a vehicle to explore movement in complex environments.
Organized sports, on the other hand, provide the same movement experience, but in a more structured setting. It is imperative to teach children coordinated movement patterns in order to help avoid injury and improve sports performance.
The functional patterns to focus on include:
- Hip hinge squat
- Abdominal bracing with pulling/pushing
- Scapular stability with thoracic extension
- Glute activation with squatting, lunging, and lateral movements (avoiding knee inward collapse)
When beginning a strength training program, the first movement a child should learn is a proper hip hinge squat. This involves proper usage of the core, glutes, and leg muscles. In a world where video gaming has become a new “sport”, often involving hours of sitting, squatting properly can be a challenge for children. Hip hinging and squatting are essential movements for nearly every land sport and essential for many strength training movements.
Abdominal bracing involves pre-activation of core muscles before lifting. Abdominal bracing is needed for spinal stabilization and to avoid injury prone postures such as sway back and rounding of the lower back. It also helps to improve the effectiveness of other core drills such as planks.
Shoulder blade control and stability is needed for pulling drills such as lat pulls, pull-ups, and rowing. It’s also essential to develop for swimmers and water athletes to create a stronger pull and to avoid overuse of the neck. Plus, it will aid in developing proper sitting and standing posture (so you can stop nagging your kids to sit up straight!).
One of the most overlooked (and most important) movement patterns to develop is proper hip and knee control with double leg squatting, single leg squatting, and jumping. A very common movement error in youth athletes is inward collapse of knees due to weakness of the gluteal muscles. This type of movement pattern is also linked to ACL injury and ankle sprains. Using resistance bands during squats, dead lifts, and jumping will help cue proper movement.
When Should Athletes Start Weight Lifting?
There is no minimum age to start strength training. A child’s physical, cognitive, and social maturity all play a role in determining when it’s appropriate to begin a training program. Children must be able to follow directions, adjust to cues, and demonstrate proper balance and coordination. It would be advised that a child undergo a screen by a medical professional such as a primary care doctor or physical therapist to determine their weight lifting readiness.
Provide Ongoing Feedback
Regardless of age, sport specialty, or skill level, athletes should be supervised and regularly evaluated in their strength programs. Adult supervision helps keep athletes safe, and continually evaluating programs can identify areas that need improvement or places where the athlete is ready to progress. Keeping an on-going dialogue regarding form and safety will help foster a body awareness that youth athletes will carry forward in their athletic career!
Kevin Vandi, DPT, OCS, CSCS
Dr. Vandi is the founder of Competitive EDGE Physical Therapy — with his background in physical therapy, orthopedics, and biomechanics, he is a highly educated, compassionate specialist. Using state-of-the-art motion analysis technology and data-driven methodologies, Kevin has assisted a wide range of clients, from post-surgery patients to youth and professional athletes. When he isn’t busy working or reading research, he spends his time with his wife Chrissy and their five wonderful children, often enjoying the outdoors and staying committed to an active lifestyle.