Association between Physical Activity and Sarcopenia among Individuals with Knee Osteoarthritis: An Observational Study

Objectives: Aging beyond 30 leads to declining muscle mass and strength with increased fat. These changes impact health, with adiposity linked to knee osteoarthritis (KOA), diabetes, heart disease, and reduced life quality. Sarcopenia’s muscle loss, combined with KOA, causes physical inactivity and joint instability, worsening disability. Physical Activity (PA) helps maintain muscle mass and mobility, while KOA patients often reduce activity, risking sarcopenia. The objective of the study is to investigate how often sarcopenia occurs in individuals with KOA and their levels of PA. Material and Methods: KOA patients were recruited from the physiotherapy outpatient department. Demographics, medical history, activity levels, and body composition data were collected. The International PA Questionnaire measured PA levels. Body composition included body mass index, muscle, and fat mass. Sarcopenia was diagnosed using muscle mass, strength, and performance. Participants provided informed consent. Data were analyzed using Statistical Package for the Social Sciences version 23. PA, sarcopenia, and KOA associations were analyzed using analysis of variance based on normality tests. Generalized linear models explored associations, adjusting for covariates. Chi-square tests assessed sarcopenia and PA relationships. Statistical significance level was p < 0.05. Results: Of the 86 participants, 37 had sarcopenia, and 49 did not. Those without sarcopenia had higher PA (4.5 days/week vs. 3.8 days/week), more vigorous activities, and less sitting time. In addition, correlation analysis showed that while lower activity levels were linked to more severe sarcopenia scores, higher PA frequency and duration were substantially associated with greater muscle mass and lower fat mass. After considering age, gender, and body weight, logistic regression showed that people who were not physically active had a 3.5-fold higher chance of getting sarcopenia. These results highlight how regular exercise helps people with KOA maintain their muscle mass and lowers their chance of developing sarcopenia. Conclusion: According to the study’s results, those who have both sarcopenia and KOA are usually less physically active in their daily lives. When compared to individuals without sarcopenia, their entire mobility, including walking, performing daily tasks, and doing PA, is significantly reduced. Their muscle strength and function could also gradually decrease as a result of their reduced PA. These results emphasize how important it is to be physically active, since individuals with KOA may be less likely to develop sarcopenia if they engage in regular PA. Promoting PA may help reduce sarcopenia risk in this population and will also be essential in improving their muscle health and quality of life.