For decades, running has been accused of damaging knees and causing long-term joint problems. However, evidence suggests running may actually benefit knee health, strengthening cartilage and bones while supporting overall well-being.
Running is a high-impact activity, generating forces two to three times your body weight with every foot strike. It’s easy to assume this would damage the knees—but the human body is designed to adapt and grow stronger under load.
The knee is a dynamic, resilient joint, with cartilage acting as a flexible cushion that protects bones and absorbs impact. Removing this load, as occurs during prolonged bed rest, can cause cartilage and bone deterioration.
How Running Strengthens Cartilage and Bones
Temporary reductions in knee cartilage thickness occur during a run, but it returns to normal within hours. Researchers believe this process promotes nutrient movement into cartilage, helping it adapt and become stronger.
Studies show that runners tend to have:
- Thicker knee cartilage compared to non-runners.
- Better bone mineral density, supporting long-term joint health.
- Potential protection against osteoarthritis, although more research is needed.
These benefits highlight running as a tool for healthy, resilient knees, in addition to its well-known advantages for heart and metabolic health.
Starting Running Later in Life
While evidence on starting running as an older adult is limited, related research offers optimism:
- Plyometric jump training in adults aged 65+ improves strength and function safely.
- Given that this training imposes higher joint loads than running, starting running later in life is likely safe with a gradual approach.
Tips for older beginners:
- Begin with intervals of walking and jogging.
- Gradually increase distance and intensity.
- Allow muscles and joints time to adapt to new loads.
Why Running Gets a Bad Reputation
Nearly half of runners experience some injury each year, often affecting the knees. However, most are overuse injuries, caused by rapid increases in load rather than running itself.
Preventing injuries involves:
- Gradual progression: Increase mileage slowly, no more than a few kilometers per week.
- Adequate nutrition: Support energy and recovery with carbohydrates, protein, calcium, and vitamin D.
- Surface choice: Running on grass or softer surfaces reduces impact compared to concrete.
With these strategies, the benefits of running far outweigh the risks, supporting healthy joints, cardiovascular fitness, and overall longevity.
Running does not inherently ruin knees. Instead, it can strengthen cartilage and bones, improve metabolic health, and support joint longevity. By progressing gradually, fueling your body properly, and listening to your limits, runners of any age can enjoy the benefits while minimizing risk.