title: Do patients with chronic low back pain have a lower level of aerobic fitness than healthy controls?: are pain, disability, fear of injury, working status, or level of leisure time activity associated with the difference in aerobic fitness level?
abstract: METHODS
  Prospective case series with historical controls (normative data).
  
  
  OBJECTIVE
  To compare the aerobic fitness level of patients with chronic low back pain (CLBP) with healthy controls matched for gender, age, and level of sport activity and to evaluate the association of the difference in aerobic fitness level with pain intensity, duration and degree of disability, fear of injury, and level of activity during work, including household and leisure time.
  
  
  BACKGROUND
  Controversy exists whether patients with CLBP have a lower level of aerobic fitness and whether this level may partly depend on the patients' activity level.
  
  
  METHODS
  A total of 108 CLBP patients completed questionnaires regarding pain, disability, fear of injury, and activity level and performed a modified Astrand submaximal cycling test. The maximum oxygen consumption (VO2max) was calculated and compared with normative data. Multiple linear regression analysis was performed with the difference of the level of aerobic fitness as dependent variable.
  
  
  RESULTS
  VO2max could be calculated in 78% of the patients. Both men and women with CLBP had significant lower VO2max than the healthy referents (10 mL/kg LBM x min(-1) and 5.6 mL/kg LBM x min(-1) respectively, P < 0.001), and this difference was significantly greater in men (P = 0.03). Multiple regression analysis showed that the level of aerobic fitness was not associated with the presumed variables. The patients who stopped the test prematurely were older (P = 0.02) and more disabled (P = 0.01).
  
  
  CONCLUSIONS
  CLBP patients, especially men, seem to have a reduced aerobic fitness level compared with the normative population. No explanatory factor for that loss could be identified.
authors.affiliation: Rehabilitation Centre Blixembosch, Eindhoven, The Netherlands. rsmeets@iae.nl
authors.forename: Rob J E M
authors.initials: RJ
authors.lastname: Smeets
authors.forename: Harriët
authors.initials: H
authors.lastname: Wittink
authors.forename: Alita
authors.initials: A
authors.lastname: Hidding
authors.forename: J André
authors.initials: JA
authors.lastname: Knottnerus
mesh_terms: D000328:Adult; D000368:Aged; D004185:Disability Evaluation; D004651:Employment; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006304:Health Status; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology / Q000523:psychology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D011788:Quality of Life; D012737:Sex Factors; D011795:Surveys and Questionnaires