Strength training improves knee health, lowers risk of knee osteoarthritis: Study

"Participants with a history of strength training had a 17% to 23% lower risk of developing frequent knee pain, radiographic OA, and symptomatic OA," reported Grace H. Lo, Michael E. DeBakey Medical Center, Houston, Texas, and colleagues.

The research team aimed to evaluate the relationship of a history of strength training with symptomatic and structural outcomes of knee OA. They conducted a retrospective, cross-sectional study within the Osteoarthritis Initiative (OAI), a multicenter prospective longitudinal observational study.

For this purpose, the researchers reviewed data on strength training and knee pain from 2607 adults. The Historical Physical Activity Survey Instrument was used to assess the impact of strength training during four periods (ages 12–18 years, 19–34 years, 3549 years, and 50 years and older). The participants were enrollees of the Osteoarthritis Initiative; 44% were male, the average age was 64.3 years, and the mean body mass index (BMI) was 28.5 kg/m2.

Strength training was defined as those exposed and those not exposed, and divided into low, medium, and high tertiles for those exposed; a total of 818 individuals were exposed to strength training, and 1789 were not exposed to strength training.

The study's primary outcomes were frequent knee pain, radiographic OA (ROA), and symptomatic radiographic OA (SOA).

The study led to the following findings:

• Strength training at any point in life was associated with a lower incidence of frequent knee pain, ROA, and SOA, compared with no strength training (odds ratios, 0.82, 0.83, and 0.77, respectively).
• When separated by tertiles, only the high-exposure group had significantly reduced odds of frequent knee pain, ROA, and SOA, with odds ratios of 0.74, 0.70, and 0.69, respectively; a dose-response relationship appeared for all three conditions, with the lowest odds ratios in the highest strength training exposure groups.
• Findings were similar for different age ranges, but the association between strength training and less frequent knee pain, less ROA, and less SOA was strongest in the older age groups.

"Our findings support the idea that the medical community should proactively encourage more people to participate in strength training to help lower their risk of osteoarthritis and other chronic conditions," the researchers write.

This study, however, was limited by its potential selection bias, observational nature, and the inability to rule out reverse causation or confounding.

Reference:

Lo, G. H., Richard, M. J., McAlindon, T. E., Kriska, A. M., Price, L. L., Rockette-Wagner, B., Eaton, C. B., Hochberg, M. C., Kwoh, C. K., Nevitt, M. C., & Driban, J. B. Strength Training Is Associated With Less Knee Osteoarthritis: Data From the Osteoarthritis Initiative. Arthritis & Rheumatology. https://doi.org/10.1002/art.42732