Physical Activity and Physical Function in Older Adults With Knee Osteoarthritis

Purpose: To assess correlates of physical activity, and to examine the relationship between physical activity and physical functioning, in 160 older (66 +/- 6 years old), overweight/obese (mean body mass index = 33.5 +/- 3.8 kg/m2), sedentary (less than 30 mins of activity, 3 days a week) individuals with knee osteoarthritis. Methods: Physical activity was measured with accelerometers and by self-report. Physical function was assessed by 6-min walk distance, knee strength, and the Short Physical Performance Battery. Pain and perceived function were measured by questionnaires. Pearson correlations and general linear models were used to analyze the relationships. Results: The mean number of steps taken per day was 6209 and the average PAEE was 237 +/- 124 kcal/day. Participants engaged in 131 +/- 39 minutes of light physical activity (LPA) and 10.6 +/- 8.9 minutes of moderate-vigorous physical activity (MPA/VPA). Total steps/day, PAEE, and minutes of MPA/VPA were all negatively correlated with age. The 6-min walk distance and lower extremity function were better in those who had higher total steps/day, higher PAEE, higher minutes of MPA/VPA, and a higher PASE score. Conclusions: This study demonstrates that a population who has higher levels of spontaneous activity have better overall physical function than those who engage in less activity.