Associations of Physical Activity With Incidence of and Recovery From Knee Pain Among Older Adults: A 3-Year Longitudinal Study

Background/Objective : Knee pain is a reversible condition that can be alleviated with appropriate interventions. Although physical activity (PA) is known to reduce knee pain, the long-term effects of different activity intensities are not well understood. This study examined the associations of moderate- and vigorous-intensity PA with the incidence and recovery from knee pain over 3 years. Methods : A longitudinal study from 2016 to 2019 in a remote area of Japan included 3,683 older adults aged ≥ 65 without functional disabilities. Knee pain was self-reported, and PA was evaluated using the International PA Questionnaire. Logistic regression analyses were conducted for participants with or without knee pain at baseline. Results : At baseline, 32.7% reported knee pain. Among those without knee pain at baseline, 16.0% developed knee pain during follow-up. By contrast, 43.8% of those with knee pain at baseline no longer reported it 3 years later. Multivariable analyses showed that older adults, both with and without baseline knee pain, who engaged in moderate-intensity PA for ≥ 300 min/week were less likely to experience knee pain in 2019. No association was found between vigorous-intensity PA and knee pain. Conclusion : Increasing moderate-intensity PA significantly decreases the risk of onset and persistence of knee pain among community-dwelling older adults. Significance/Implications : Given that knee pain is a common condition that can severely affect mobility and quality of life, encouraging a more active lifestyle, particularly with moderate-intensity activities, can have substantial public health benefits.