Individuals with a history of strength training have a lower prevalence of frequent knee pain, radiographic knee osteoarthritis (OA), and symptomatic OA, challenging the misconception that strength training may harm knee health, according to results of a retrospective, cross-sectional study published in the Arthritis & Rheumatology.
The World Health Organization and the United States Department of Health and Human Services have long advocated for the incorporation of weekly muscle-strengthening activities to reap a host of health benefits, including enhanced functional capacity and increased bone strength. Despite these recommendations, less than 1 in 3 adults in the United States meet this guideline. Fear that strength training could lead to joint pain or arthritis in weight-bearing joints may contribute to the limited number of patients engaging in these activities. To alleviate any doubt, researchers explored the relationship between lifelong strength training and symptomatic/structural knee OA outcomes.
Data were sourced from the multicenter, prospective, longitudinal, observational, Osteoarthritis Initiative cohort. Individuals at different stages of OA progression — those who did not have knee OA, were at a high risk of developing knee OA, or had existing symptomatic knee OA — were included in the analysis.
Participants completed the Historical Physical Activity Survey Instrument at month 96 and were asked to identify strength-training activities that they most frequently engaged in during 4 different time periods: ages 12 to 18, 19 to 34, 35 to 49, and age 50 onward. Information on the duration, frequency, and intensity of their top 3 activities was collected.
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Our findings support the idea that the medical community should proactively encourage more people to participate in strength training to help reduce their risk of osteoarthritis and other chronic conditions.
Primary study outcomes included knee pain frequency, radiographic OA (defined as Kellgren-Lawrence grade ≥2), and symptomatic OA.
The study included 2607 participants with an average age of 64.3 years and an average body mass index of 28.5 kg/m2. Among them, 39% reported frequent knee pain, 58% had radiographic knee OA, 28% had symptomatic knee OA, 4% received total knee replacement, and 49% had a history of prior knee injury.
Of the total participants, 818 had a history of strength training while 1789 did not.
Participants with a history of strength training had a 17% to 23% lower likelihood of experiencing frequent knee pain, radiographic OA, and symptomatic OA.
When participants were grouped by their level of strength training exposure (tertiles), only the high exposure group showed significant benefits for frequent knee pain (odds ratio [OR], 0.74), radiographic OA (OR, 0.70), and symptomatic OA (OR, 0.69). As the level of strength training increased, the odds of prevalent OA-related outcomes decreased, with the most significant benefits observed in the highest exposure group.
Age-stratified results demonstrated that more individuals participated in strength training activities during later periods in life. The positive association of strength training with reduced knee pain, radiographic OA, and symptomatic OA was most prominent among the more advanced age ranges, suggesting that strength training may be particularly beneficial for older individuals in terms of joint health.
This study was limited by its observational nature, potential selection bias, and the inability to rule out reverse causation or confounding.
Study authors concluded, “Our findings support the idea that the medical community should proactively encourage more people to participate in strength training to help reduce their risk of osteoarthritis and other chronic conditions.”
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