Daily Physical Activity And Pain Relationships In Femoroacetabular Impingement Syndrome

PURPOSE: Investigate between-person and within-person relationships between objectively assessed PA and pain using ecological momentary assessments (EMAs; evaluations that occur in the real-world in real-time) of pain. METHODS: 27 individuals with a clinical diagnosis of FAIS wore an activity monitor on the waist for 7 days and were prompted to report their pain (0-100) via EMAs 6x/day with a link sent to their smartphone. For the 60 minutes prior to each EMA, PA was categorized as sedentary, light, or moderate-to-vigorous (MVPA). Average time spent in each category and activity fluctuation outside of this average were calculated for each participant. Linear mixed-effects models were used to investigate the between-person (i.e., person average PA) and within-person (i.e., momentary difference in PA from the average) relationships between PA and subsequent EMA-reported pain. RESULTS: At the between-person level, increased time spent in light PA in the 60 min prior to an EMA was associated with more pain (p = .017). At the within-person level, when participants spent more time in sedentary behavior than usual, they reported less pain (p < .001), such that for every 15 additional minutes of sedentary time, pain decreased by 2.8 units. When individuals spent more time than usual in light PA and MVPA, they reported more pain (p < .001) such that for every 15 additional minutes of light PA and MVPA, pain reported in the subsequent EMA increased by 3.4 units and 5.7 units, respectively. CONCLUSIONS: PA across the intensity spectrum is related to subsequent elevations in pain at the momentary level. These data highlight that pain may be a potent daily barrier to PA in this population, and that focused work identifying activities that provide the medicine of PA while minimizing pain is strongly needed.