No, Working Out Does Not Stunt Growth
Exercise does not stunt growth in children and adolescents—in fact, properly supervised physical activity, including resistance training, supports healthy growth and development without negatively impacting height or maturation. 1
The Evidence is Clear
The most recent international guidelines explicitly state that children and adolescents who learn and practice correct resistance training principles under proper supervision can improve muscle strength without any negative impact on physical growth and development 1. This directly contradicts the persistent myth that "working out" stunts growth.
What the Guidelines Recommend
Children and adolescents should:
- Accumulate at least 60 minutes of moderate-to-vigorous physical activity daily 2, 1
- Engage in muscle and bone strengthening activities at least 3 times per week 1
- Include activities like jumping, skipping, hopping, bodyweight exercises, and light weights under supervision 1
These recommendations are based on evidence showing that physical activity during growth years:
- Improves bone health and density
- Enhances muscular fitness
- Supports cardiometabolic health
- Reduces injury risk when done properly
- Does not interfere with normal height development 2, 3, 4
Understanding the Nuance: When Exercise Might Affect Growth
The critical distinction is between normal exercise and extreme training with inadequate nutrition. Research shows that experimental resistance training programs with proper supervision do not negatively impact growth in height and weight 5. However, one older study found that elite female gymnasts training over 18 hours per week with dietary restriction showed reduced growth velocity 6. This was attributed to severe energy deficiency and metabolic stress—not the exercise itself 7, 8.
The key factors that protect growth are:
- Adequate caloric and nutritional intake to support both training and growth
- Proper supervision and age-appropriate training loads
- Avoiding excessive training volume (>18-20 hours/week of intensive training)
- Not combining extreme training with caloric restriction 6, 7
The Real Benefits for Growing Bodies
Physical activity during adolescence provides lifelong benefits 3, 4:
- Increases peak bone mass, reducing osteoporosis risk later
- Builds muscle mass and strength safely
- Improves insulin sensitivity and metabolic health
- Enhances cognitive function and academic performance 2
- Supports mental health and reduces depression 2
Common Pitfalls to Avoid
Do not:
- Restrict calories while training intensively
- Allow unsupervised heavy resistance training
- Permit single-sport specialization at young ages 1
- Train at extreme volumes (>18-20 hours/week) before full maturation
Do:
- Ensure proper warm-up and cool-down 1
- Provide adequate nutrition to support both activity and growth
- Use proper form and technique under qualified supervision 1, 5
- Include variety in physical activities 1
The injury rates in supervised youth resistance training programs are remarkably low (0.053-0.176 per 100 participant-hours) 5, making properly conducted exercise programs very safe.
Bottom line: Encourage children and adolescents to be physically active, including strength training, with proper supervision and adequate nutrition—this supports rather than impairs their growth.