Frequency of Aerobic Exercise and Association with Pain and Function in Older Adults with Knee Osteoarthritis: A Cross-Sectional Study

Knee osteoarthritis is a leading cause of pain and functional limitation in older adults, and exercise is widely recommended as a core component of conservative management; however, the optimal frequency of aerobic and strengthening exercise remains unclear. This cross-sectional study aimed to examine the association between exercise frequency, pain, and functional outcomes in older adults with knee osteoarthritis. Participants aged ≥60 years with a clinical diagnosis of knee osteoarthritis were recruited from a tertiary university hospital in Thailand. Exercise frequency over the previous four weeks was categorized as none, 1-2 times per week, 3-6 times per week, or every day. Outcomes were assessed using the Thai version of the modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Brief Pain Inventory. Nonparametric analyses and multivariable regression analyses adjusted for age, body mass index, and comorbidities were performed. A total of 140 participants were included, of whom 68.6% reported engaging in aerobic exercise, and 56.4% performed knee-strengthening exercises. Higher frequency of aerobic exercise was significantly associated with lower pain severity, reduced pain interference, and better WOMAC total and subdomain scores (<i>p</i> < 0.05). A graded association pattern was observed, with the greatest benefits seen in participants performing aerobic exercise 3-6 times per week. No significant associations were identified between knee strengthening exercise frequency and pain and functional outcomes. These findings suggest that frequent aerobic exercise is associated with reduced pain and improved function in older adults with knee osteoarthritis, supporting its role in primary care and rehabilitation management.