Accelerometric assessment of physical performance during the sit-to-stand test in knee osteoarthritis: A cross-sectional study

Introduction: Knee osteoarthritis is the most common rheumatic disease, which causes functional disability and impairment in quality of life. The aim of this study was to evaluate physical performance in knee osteoarthritis by clinical tests and accelerometer measurements and analyze factors associated with physical performance alteration. Methods: This is a cross-sectional study, included 40 women with knee osteoarthritis. All participants were instructed to perform sit-to-stand transfers during 30 seconds. We measured the speed, force and muscular power of the lower limbs during this test using the Myotest PRO® accelerometer. A correlation analysis was performed in search of factors associated with physical performance alteration. Results: The median speed during the sit-to-stand test was 4.3 [3.1-6.2] cm/sec. The median muscular force and power during this test were 15.2 [13.6-17.7] Nm/kg and 14.5 [9.9-21.7] W/kg respectively. Body mass index (BMI) correlated negatively with the 3 parameters of physical performance measured by the Myotest PRO® accelerometer (speed, force and muscular power) during the sit-to-stand test. Conclusions: This pilot study assessed the physical performance of the lower limbs in knee osteoarthritis subjects, by measuring the speed, force and muscle power during the sit-to-stand test. It suggests an association between obesity and physical performance impairment.