Influence of Varying Squat Exposure on Knee Pain and Function among People with Knee Osteoarthritis

Knee osteoarthritis (OA) is a leading cause of pain and functional disability globally. Knowledge about the influence of high-flexion postures on knee function among people with knee OA is limited. Sustained occupational squatting is assumed to increase tibio-femoral and patella-femoral compressive force and knee osteoarthritis. Additionally, people spend varying amounts of time in deep squat for performing self-care, activities of daily living (ADL), and leisure. Hence, a study was conducted to explore the influence of varying squat exposure on knee pain and function. An interview-based survey was conducted inclusive of 300 participants, following institutional ethical approval and informed consent. Participants were classified based on daily squat exposure using a validated tool: the MGM Ground Level Activity Exposure Questionnaire. Knee pain and function were assessed using the Numeric Rating Scale and the Modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. Thirty-three people from the study cohort (Nonsquatters n = 13, ADL squatters n = 10, occupational squatters n = 10) were evaluated for knee motion, muscle strength, and balance using 2D motion analysis, 30-second chair-stand test, calf-raise test, 30-second deep-squat test, single-leg stance test, and star excursion test, respectively. Prevalence of knee pain was 27% in squatters and 21% in nonsquatters. People with higher squat exposure demonstrated greater knee motion, muscle strength, and balance compared with nonsquatters. Occupational squatters continued to work on a higher level of function despite pain and difficulty. Deep-squat activity performed in moderation is a potentially beneficial activity to maintain knee range, muscle strength, and balance.