title: Association between physical activity and pain processing in adults with chronic low back pain compared to pain-free controls.
abstract: BACKGROUND
  Pain sensitivity has been negatively associated with physical activity levels. Few studies have examined associations between experimentally induced pain sensitivity and physical activity in adults with chronic low back pain and pain-free controls.
  
  
  OBJECTIVE
  The objective of this study was to examine associations between physical activity levels and how an individual processes pain using experimentally induced pain stimuli.
  
  
  METHODS
  Seventy subjects (CLBP = 49; mean age = 46.8 ± 14.9; Pain-free = 21; mean age = 45.3 ± 18.2, n of females = 46) participated. A self-report questionnaire derived from the International Physical Activity Questionnaire (IPAQ) was used to calculate an activity level index. Pain sensitivity was assessed via quantitative sensory testing (QST) at the right lower extremity.
  
  
  RESULTS
  Moderate (U = 688, p< 0.05) and vigorous (U = 649, p< 0.05) physical activity levels were higher in pain-free vs. individuals with CLBP. Activity level was not associated with pain sensitivity (Pain-free: R2 = 0.02, p> 0.05; CLBP: R2 = 0.01, p> 0.05). Both moderate (R2 = 0.49, p< 0.05) and vigorous (R2 = 0.68, p< 0.01) physical activity were associated with pain modulation amongst pain-free individuals.
  
  
  CONCLUSIONS
  Findings suggest that physical activity influences pain modulation amongst pain-free individuals, however no relationship exists once CLBP is present. However, future investigation will elucidate the extent to which physical activity level either prevents CLBP or is effective in alleviating CLBP.
authors.affiliation: Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA.
authors.forename: Lindsay C
authors.initials: LC
authors.lastname: Orr
authors.affiliation: Duke Clinical Research Institute, Department of Orthopaedic Surgery, Duke University, Durham, NC, USA.
authors.forename: Steven Z
authors.initials: SZ
authors.lastname: George
authors.affiliation: Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA.|Pain Research & Intervention Center of Excellence, University of Florida, Gainesville, FL, USA.
authors.forename: Corey B
authors.initials: CB
authors.lastname: Simon
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002908:Chronic Disease; D059350:Chronic Pain / Q000503:physiopathology*; D015444:Exercise; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D059408:Pain Management; D010147:Pain Measurement; D058748:Pain Perception; D017288:Pain Threshold; D057566:Self Report; D011795:Surveys and Questionnaires
keywords: Physical activity; chronic low back pain; pain modulation