title: Relative contribution of mental health and exercise-related pain increment to treadmill test intolerance in patients with chronic low back pain.
abstract: METHODS
  A cross-sectional study.
  
  
  OBJECTIVE
  To determine the relative contribution of pain increase and mental health to testing performance during a single bout of exercise in patients with chronic low back pain.
  
  
  BACKGROUND
  Controversy exists as to which factors principally limit physical performance in patients with chronic low back pain. Some believe psychological factors limit physical performance, whereas others believe activity-related increases in pain intensity limit performance.
  
  
  METHODS
  Seventy-five patients with chronic low back pain reported pain intensity before and after undergoing a maximal, symptom-limited modified treadmill test. Walking time (in minutes) and aerobic fitness were measured. The Short Form 36 Health Survey was administered to all patients.
  
  
  RESULTS
  Fifty-four percent of the sample stopped testing because of a significant increase in pain intensity (P = 0.0001). Treadmill performance was lower in patients who stopped because of pain than in those who stopped because of fatigue (P = 0.02). The patients who stopped because of pain were also more likely to have low mental health as assessed by the Short Form 36 Health Survey. Low mental health, however, did not have a statistically significant influence on treadmill performance.
  
  
  CONCLUSIONS
  The data indicate that impairment of physical performance during treadmill testing in patients with chronic low back pain is attributable to testing-induced increase in pain intensity rather than to individual low mental health scores.
authors.affiliation: New England Medical Center, Pain Management Program, Boston, MA 02111, USA. Hwittink@lifespan.org
authors.forename: H
authors.initials: H
authors.lastname: Wittink
authors.forename: W
authors.initials: W
authors.lastname: Rogers
authors.forename: C
authors.initials: C
authors.lastname: Gascon
authors.forename: A
authors.initials: A
authors.lastname: Sukiennik
authors.forename: D
authors.initials: D
authors.lastname: Cynn
authors.forename: D B
authors.initials: DB
authors.lastname: Carr
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology* / Q000523:psychology*; D005080:Exercise Test; D005260:Female; D006304:Health Status; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D010147:Pain Measurement; D017288:Pain Threshold; D011795:Surveys and Questionnaires