Sensitivity to physical activity was related to measures of central sensitization and pain catastrophizing and cross-sectionally predicted worse pain, function, and physical performance.
Recent findings suggest that certain individuals with musculoskeletal pain conditions have increased sensitivity to physical activity (SPA) and respond to activities of stable intensity with increasingly severe pain. This study aimed to determine the degree to which individuals with knee osteoarthritis (OA) show heightened SPA in response to a standardized walking task and whether SPA cross-sectionally predicts psychological factors, responses to quantitative sensory testing (QST), and different OA-related outcomes. One hundred seven adults with chronic knee OA completed self-report measures of pain, function, and psychological factors, underwent QST, and performed a 6-min walk test. Participants rated their discomfort levels throughout the walking task; an index of SPA was created by subtracting first ratings from peak ratings. Repeated-measure analysis of variance revealed that levels of discomfort significantly increased throughout the walking task. A series of hierarchical regression analyses determined that after controlling for significant covariates, psychological factors, and measures of mechanical pain sensitivity, individual variance in SPA predicted self-report pain and function and performance on the walking task. Analyses also revealed that both pain catastrophizing and the temporal summation of mechanical pain were significant predictors of SPA and that SPA mediated the relationship between catastrophizing and self-reported pain and physical function. The discussion addresses the potential processes contributing to SPA and the role it may play in predicting responses to different interventions for musculoskeletal pain conditions.
aSchool of Medicine, Johns Hopkins University, Baltimore, MD, USA
bDepartment of Anaesthesia, Harvard School of Medicine, Boston, MA, USA
cCenter for Military Psychiatry and Neurosciences Research, Walter Reed Army Institute of Research, Silver Spring, MD, USA
* Corresponding author. Address: Johns Hopkins University, Bayview Campus, Center for Mind–Body Research, 5510 Nathan-Shock Dr, Suite 100, Baltimore, MD 21224, USA. Tel.: +1 (202) 569 9763; fax: +1 (410) 550 0117.
Received 21 August 2013
Received in revised form 28 November 2013
Accepted 20 December 2013
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