Among patients with knee osteoarthritis (KOA), increases in daily physical activity are associated with concurrent increases in pain intensity, particularly among those reporting higher levels of pain catastrophizing. This according to a recent study that examined the day-to-day association between physical activity and pain intensity among a sample of patients with KOA and the potential moderation of this association by negative cognitive processes. 121 patients with KOA completed questionnaires assessing pain and psychosocial functioning and were then asked to report levels of physical activity and pain intensity once per day for a period of 7 days using an electronic diary. Researchers found:

• Day-to-day increased in physical activity were associated with heightened levels on pain intensity.
• The association between physical activity and pain intensity was moderated by catastrophizing.
• This effect was specific to catastrophizing, as depression and anxiety did not moderate the activity-pain relationship.