title: The effects of lumbar extensor strength on disability and mobility in patients with persistent low back pain.
abstract: BACKGROUND
  It is assumed that low back pain patients who use pain-avoiding immobilizing strategies may benefit from specific back flexion and extension exercises aimed at reducing sagittal lumbar hypomobility. The aim of this study was to test this potential working mechanism in chronic low back pain patients undergoing lumbar extensor strengthening training.
  
  
  METHODS
  A single-group prospective cohort design was used in this study. Patients with persistent low back complaints for at least 2 years were recruited at a specialized physical therapy clinics center. They participated in a progressive 11-week lumbar extensor strength training program, once a week. At baseline, sagittal lumbar mobility in flexion and extension was measured with a computer-assisted inclinometer. Self-rated pain intensity was measured using a visual analogue scale, back-specific functional status was assessed with the Quebec Back Pain Disability Scale and the Patient Specific Complains questionnaire.
  
  
  RESULTS
  Statistically significant improvements were found in pain (28% decrease) and functional disability (23% to 36% decrease). Most progress was seen in the first 5 treatment weeks. Lumbar mobility in flexion showed non-significant increases over time (+12%). Pre-post treatment changes in flexion and extension mobility did not contribute significantly to the models. The retained factors together explained 15% to 48% of the variation in outcome.
  
  
  CONCLUSIONS
  Specific lumbar strengthening showed clinically relevant improvements in pain and disability in patients with persistent chronic low back pain. These improvements did not necessarily relate to improvements in lumbar mobility. Parameters representing other domains of adaptations to exercise may be needed to evaluate the effects of back pain management.
authors.affiliation: Department of Training Medicine and Training Physiology, Personnel Command, Royal Netherlands Army, Utrecht, The Netherlands - ph.helmhout.01@mindef.nl.
authors.forename: Pieter H
authors.initials: PH
authors.lastname: Helmhout
authors.affiliation: Department of Clinical Human Movement Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Marloes
authors.initials: M
authors.lastname: Witjes
authors.affiliation: Scientific Institute for Quality of Healthcare, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Ria W
authors.initials: RW
authors.lastname: Nijhuis-VAN DER Sanden
authors.affiliation: Scientific Institute for Quality of Healthcare, Radboud University Medical Centre, Nijmegen, The Netherlands.|Physical Therapy Practice for Musculoskeletal Disorders of the Neck, Shoulder, and Upper Extremity, Groningen, The Netherlands.
authors.forename: Carel
authors.initials: C
authors.lastname: Bron
authors.affiliation: Fysius Back Experts Center, Doetinchem, The Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: van Aalst
authors.affiliation: Scientific Institute for Quality of Healthcare, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: J Bart
authors.initials: JB
authors.lastname: Staal
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001415:Back; D004185:Disability Evaluation; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology* / Q000534:rehabilitation; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D010147:Pain Measurement; D011446:Prospective Studies; D016059:Range of Motion, Articular; D055070:Resistance Training / Q000379:methods; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D055815:Young Adult