With growing public interest in health and fitness, an increasing number of teenagers are embracing exercise, particularly strength training, as part of their daily routines. While strength training can improve physical strength and muscle mass, it also comes with potential health risks. For adolescents who are still in the developmental stage, starting strength training too early may adversely affect the closure of growth plates, potentially disrupting normal bone development.

Understanding Growth Plates and Bone Development：

First, it's essential to understand the concept of "growth plates." Growth plates are the areas of cartilage located at the ends of long bones and play a crucial role during growth. For adolescents, they serve as the control centers for bone development. As teens mature, these growth plates gradually close, signaling the end of bone growth. Generally, growth plates close around age 18 in females and around age 20 or later in males.

Before closure, bones are in a rapid growth phase and are relatively weak and flexible, making them more vulnerable to injury from external forces. Excessive or improper strength training during this phase may interfere with the normal development of growth plates, possibly leading to irreversible damage. Therefore, using appropriate training methods and timing is particularly important for teenagers.

The Impact of Strength Training on Adolescent Bone Development：

Strength training typically involves muscle contractions that generate force using weights such as barbells, dumbbells, or machines. While this type of training is effective for adults—enhancing fitness, improving bone density, and preventing osteoporosis—adolescents have different physiological conditions. Their bones are still growing, and their growth plates remain open, making the effects of strength training more complex.

Early Strength Training May Affect Growth Plate Development：

Since teenagers' bones are in a rapid growth phase, their capacity to withstand external force is lower. High-intensity or excessive strength training during this time—especially involving heavy weights—can place too much stress on the growth plates, potentially causing them to close prematurely. This may not only stunt growth in height but could also result in bone deformities or serious injuries.

Increased Risk of Injury：

Adolescents' muscles and bones are not as developed as those of adults, and their joints and ligaments are less flexible and stable. Improper strength training can result in muscle strains, joint sprains, or even fractures. The use of excessive weight or overly intense exercise further increases the risk of injury. Over time, repeated injuries can affect not only short-term health but also long-term bone development.

Potential Negative Effects on Bone Density and Strength：

While moderate resistance training can enhance bone density in adults, excessive strength training may have the opposite effect in adolescents. Research shows that premature involvement in heavy strength training may suppress normal bone growth, reduce bone strength, and increase the risk of fractures in the future. During the critical window of bone development, improper exercise can negatively impact lifetime bone health.

How to Structure Strength Training Safely for Adolescents？

Despite the risks, properly conducted strength training can still offer benefits to teens, including improved muscle strength, athletic performance, and coordination. The key lies in organizing training programs scientifically and avoiding excessive or improper practices.

Gradual Progression and Avoiding Early High-Intensity Training

Strength training for teenagers should be progressive. It’s best to start with low-intensity, low-resistance exercises to allow the body to adapt gradually. During early developmental stages, high-intensity training should be avoided. Generally, teens can begin appropriate strength training around age 12, but the intensity should not exceed 10%–20% of their own capacity. Before the age of 18, and especially before the closure of growth plates, training should focus on building muscular endurance and general strength rather than maximizing power.

Choosing Appropriate Training Methods：

In addition to traditional weight training with barbells and dumbbells, adolescents can engage in lower-impact, more stable exercises, such as resistance band workouts or bodyweight training (like push-ups and pull-ups). These methods are effective for building muscle and bone strength while placing less stress on the growth plates.

Improving Flexibility and Stability：

Strength training for teenagers should be complemented by exercises that improve joint flexibility and stability. Proper joint mobility and strong muscles can protect bones and reduce the likelihood of injuries caused by poor posture or movement mechanics during training.

Maintaining a Healthy Diet to Support Bone Growth：

Besides exercise, proper nutrition is vital to bone health in teenagers. They should consume sufficient calcium, phosphorus, and vitamin D to promote healthy bone development. Adequate protein intake is also important for muscle growth and recovery.

Conclusion

Teenagers’ fitness routines should prioritize health and safety by avoiding high-intensity strength training too early. When done correctly, strength training can improve physical fitness, support healthy bone development, and foster lifelong exercise habits. Before beginning a strength training regimen, teens should fully understand their own physical condition, consult professional trainers, and follow a scientifically designed training program. This approach will help prevent health problems caused by premature or excessive training and promote well-rounded physical and mental development.