Scientists Explain How Adults Can Protect Knee Health Through Aging

Adults can preserve knee function through aging by staying active and managing injury risks, according to research reviewed by the Washington Post. The guidance explains how knees change from young adulthood through later life and why exercise, strength and movement matter.

The knee is a hinge joint supported by the femur, tibia and patella, with cartilage, ligaments, menisci and synovial fluid helping it function. According to researchers cited by the Washington Post, modern evidence suggests knees are more resilient than many people previously believed.

A 2022 study of 2,514 adults led by Jean-Francois Esculier found that more than half believed distance running increased arthritis risk. Research cited in the report indicates runners are generally less likely than others to develop painful knee arthritis, and their condition often progresses more slowly if it appears.

Esculier, a physical therapist and clinical associate professor of medicine at the University of British Columbia in Kelowna, said public beliefs about knee health often differ from research findings.

"People have strong opinions" said Jean-Francois Esculier, a physical therapist and clinical associate professor of medicine at the University of British Columbia in Kelowna.

The report explained that movement helps cartilage through cyclic loading, a process where pressure during activity pushes fluid out and recovery during straightening draws in oxygen and nutrients. A 2024 study found walking for 10 minutes restored young adults' knee cartilage three times faster than rest.

Keith Baar, an exercise scientist at McMaster University in Canada, highlighted physical activity as a central factor in maintaining joints during early adulthood.

"The key" said Keith Baar, an exercise scientist at McMaster University in Canada.

During the 20s and 30s, knee cartilage is typically at its healthiest, but muscle mass and strength begin declining around age 30. The report noted that sports injuries, including anterior cruciate ligament tears, can increase later arthritis risks, with ACL injury rates peaking around age 25 in men and 18 in women.

In middle age, knee changes become more common. According to the Washington Post report, knee arthritis is typically diagnosed around age 55, while cartilage thinning, reduced muscle strength and weight gain can add stress to joints.

A 2018 study cited in the report found articular cartilage tears in nearly half of adults aged 40 or older who received knee scans, many without reported pain. A separate finding showed almost 20 percent had meniscus tears.

Exercise during midlife may reduce later problems. A 2024 study of 2,607 men and women found resistance training before age 50 lowered the risk of later knee pain or arthritis by 20 percent or more, according to the report.

For older adults, knee replacements become more common, with most of nearly 800,000 annual knee replacements in the United States performed among people in their 60s, according to the Washington Post.