The belief that resistance exercises, such as the bench press, can stop or stunt an adolescent’s growth is a persistent and widespread concern. This idea stems from a misunderstanding of how bones grow and the difference between controlled exercise and traumatic injury. Scientific evidence consistently shows that when performed correctly under supervision, resistance training does not negatively impact a child’s final adult height. The focus should shift from worrying about stunted growth to ensuring proper technique and safety protocols are followed to reap the numerous benefits of strength development.
The Role of Growth Plates in Skeletal Development
The structure at the heart of this concern is the growth plate, technically known as the epiphyseal plate. These specialized areas of cartilage are found near the ends of the long bones in children and adolescents. Growth plates function as the primary site of bone elongation, where cartilage cells divide and mature, eventually hardening into solid bone through ossification. This lengthening process is what allows a child to grow taller. Because the growth plate is made of softer cartilage rather than mature bone, it is structurally weaker and more vulnerable to injury than surrounding tissues.
As a person reaches the end of puberty, typically between the ages of 15 and 17 for boys and 13 and 15 for girls, these plates naturally close. Once closed, the cartilage is entirely replaced by solid bone, and the bone can no longer increase in length, marking the end of linear growth. This period of vulnerability is why the myth about resistance training causing stunted growth became established.
Separating Injury Risk from Stunted Growth
The notion that resistance training itself stunts growth is not supported by decades of scientific research. Major health organizations, including the American Academy of Pediatrics, confirm that appropriately designed and supervised programs do not negatively affect a child’s linear growth or cause premature fusion of the growth plates. The concern arises from confusing the physical stress of controlled exercise with the mechanism of an acute injury.
An intense, sudden, and traumatic force—such as a fall or a collision in contact sports—can cause a fracture to the growth plate. If this severe injury occurs, it can potentially disrupt ossification, leading to a permanent difference in limb length or a crooked bone. This result is a consequence of traumatic injury, not a result of engaging in the exercise itself.
The vast majority of injuries related to youth strength training are caused by improper technique, excessive weight, or a lack of qualified supervision. Controlled resistance training can strengthen the surrounding muscles, tendons, and ligaments, which helps reduce the risk of injury during other physical activities. Benefits also include increased bone density and a lower risk of fractures.
Primary Determinants of Final Adult Height
An individual’s final adult height is primarily determined by factors unrelated to resistance training. Genetics is the overwhelming determinant of stature, accounting for approximately 80% of a person’s height variation. This genetic blueprint sets the potential range for final height.
Environmental factors account for the remaining percentage, largely related to overall health during childhood and adolescence. Severe childhood malnutrition or certain untreated chronic medical conditions, such as hormonal imbalances, are the actual causes of medically defined “stunted growth.” Resistance training is a lifestyle choice that has a negligible effect on the genetic and medical factors that govern height.
Guidelines for Safe Resistance Training in Youth
For adolescents interested in resistance training, safety and effectiveness depend on following proper protocols. The focus must always be on mastering the movement pattern before attempting to increase the load. This means starting with bodyweight exercises or very light resistance to ensure the form is perfect.
Once technique is proficient, weight should be added incrementally, typically in small 10% increases. Adolescents should adhere to the following guidelines:
- The goal should be to complete a set of 8 to 15 repetitions with good form.
- Avoid competitive powerlifting, bodybuilding, or attempting maximal lifts (1-rep maximums), as these activities carry a higher risk of injury.
- Qualified adult supervision is essential to provide instruction and correct form immediately.
- Ensure a safe training environment.