Adolescent Bone Development and Running Volume Limits: How to Avoid Growth Plate Injuries

Introduction

Every year, numerous sports injuries caused by “overtraining” occur among junior high and high school track and field teams across Taiwan’s cities and counties, with growth plate injuries being particularly concerning. The growth plate (epiphyseal plate) is the cartilage region at the ends of long bones responsible for longitudinal bone growth, which does not fully ossify and close until approximately ages 16–18 in boys and 14–16 in girls. Before closure, this region is far weaker than the surrounding bone, making it one of the most vulnerable injury sites for adolescent runners.

This article aims to help parents, school physical education teachers, and grassroots track and field coaches understand the mechanisms of growth plate injuries and provide practical, actionable recommendations for managing running volume.

Mechanisms and Common Types of Growth Plate Injuries

Why Does Running Easily Injure the Growth Plate?

When running, the ground reaction force absorbed by the heel with each step is approximately 2–3 times body weight. For a junior high school student weighing 50 kg, the impact force of each step reaches 100–150 kg. When cumulative running volume exceeds the body’s adaptive capacity, repeated microtrauma accumulates at the growth plate, resulting in apophysitis or avulsion fractures.

Common Growth Plate-Related Injuries in Adolescent Runners

Among these, Sever’s Disease and Osgood-Schlatter Disease are the two most common growth plate problems in Taiwanese middle school track and field teams. Many coaches mistakenly treat them as ordinary muscle soreness and ignore them, leading to worsening injuries.

Scientific Basis for Safe Running Volume

The 10% Rule for Weekly Mileage

The “10% rule,” widely adopted in sports medicine, states that weekly running volume should not increase by more than 10% from the previous week. This principle is already a conservative lower limit for adults; for adolescents whose growth plates have not yet closed, it is recommended to further compress this to “increase by 10% every two weeks.”

Reference Running Volume Limits by Age and Sex

The following are reference values for the maximum safe weekly running volume recommended by sports science under common Taiwanese school team training conditions—they are not training goals:

• Junior high 1st–2nd year (ages 12–14): No more than 20–25 km per week
• Junior high 3rd year to high school 1st year (ages 14–16): No more than 30–35 km per week
• High school 2nd–3rd year (ages 16–18, growth plates nearing closure): No more than 40–50 km per week (girls should aim for the lower end)

Important Note: The figures above are for reference only; individual variation is enormous. Children who are tall for their age or experiencing a growth spurt actually need reduced running volume, because their growth plates are in their most active and most vulnerable period.

Protective Strategies in Training Plans

Avoiding Consecutive Days of High-Intensity Training

• Schedule at least 2 complete rest days per week
• After high-intensity training (interval runs, tempo runs), arrange an easy run or cross-training the following day
• Plan a 3–5 day tapering period before and after races

The Importance of Cross-Training

Low-impact activities such as swimming, cycling, and using an elliptical machine can maintain cardiorespiratory fitness while allowing the growth plates to recover from cumulative stress. It is recommended that adolescent runners incorporate at least one non-running aerobic session per week.

Choosing Running Surfaces

When conditions allow, prioritize:

1. Track (PU synthetic surface)
2. Grass or dirt trails
3. Asphalt (last choice)

Avoid prolonged running on concrete, as its impact force is approximately 40% higher than that of a track.

Practical Recommendations

1. Regularly ask children about pain: After training, proactively ask “Is anything uncomfortable?” rather than waiting for the child to speak up
2. Keep a pain diary: Record the pain location, timing, and severity (on a 1–10 scale) to help determine whether it is an overuse injury
3. Stop training immediately when pain appears: Growth plate injuries are characterized by “you can still run if you push through,” but continuing to run will cause the injury to deteriorate rapidly
4. Seek sports medicine or orthopedics: After diagnosis, follow up with physical therapy; never self-medicate with pain patches and continue training through injury
5. Coaches and parents must communicate: Do not let a “fear of losing” mentality override health and safety

Conclusion

What makes growth plate injuries so insidious is that minor injuries often present no obvious symptoms, and children are unlikely to notice them on their own. By the time pain becomes evident, the injury is often already moderate or severe. Grassroots track and field training culture in Taiwan sometimes overemphasizes results and mileage. Parents and coaches must jointly establish a consensus: protecting adolescents’ growth plates means protecting their athletic future for the next ten to twenty years. Appropriate running volume limits are not a sign of complacency—they are the smartest long-term investment.

Related Reading

• Adolescent Road Running Training: The Scientific Basis for Growth Plate Protection and Weekly Mileage Limits
• Adolescent Running Safety: Training Volume, Intensity, and Long-Term Development During Growth
• Running Mileage Recommendations for Adolescents: Safe Weekly Running Volume Limits for Middle School Students
• Sports Science for Children and Adolescents: Training Principles During Development—Growth Plates, Early vs. Late Maturation, and the Safety of Youth Strength Training