title: A high-intensity lumbar extensor strengthening program is little better than a low-intensity program or a waiting list control group for chronic low back pain: a randomised clinical trial.
abstract: OBJECTIVE
  Is eight weeks of high-intensity strengthening of the isolated lumbar extensors more effective than low-intensity strengthening or no strengthening? Are any gains maintained 16 weeks later?
  
  
  METHODS
  Randomised, three-arm trial with concealed allocation, assessor blinding, and intention-to-treat-analysis. Participants in the waiting list control group were randomised again, after the first 8 weeks, to either the high-intensity or the low-intensity strengthening program.
  
  
  METHODS
  Sixty-five army personnel with non-specific chronic low back pain.
  
  
  METHODS
  The high-intensity training group received 10 sessions of 15 to 20 repetitions for the isolated lumbar extensor muscles. The low-intensity training group received a nonprogressive, low-intensity resistance protocol.
  
  
  METHODS
  Primary outcomes were global perceived effect and disability. Secondary outcomes were health-related quality of life, fear of movement/(re-)injury, and isometric lumbar extensor muscle strength. Measures were taken before and after the training and 16 weeks later.
  
  
  RESULTS
  At eight weeks, SF-36 overall score was on average 7% (95% CI 1 to 13) greater in the high-intensity training group compared with the low-intensity training group and the waiting list control group, and self-assessed decrease of back symptoms was on average 39% (95% CI 14 to 64) greater in the high-intensity training group compared with the waiting list control group. There was no difference in improvement between the groups for any other outcome at 8 weeks or 24 weeks.
  
  
  CONCLUSIONS
  Although some beneficial effects were found, the results of this high-intensity strengthening program of the isolated lumbar extensor muscles do not clearly support the generally-claimed beneficial influence of exercise for chronic non-specific low back pain.
authors.affiliation: Department of Training Medicine and Training Physiology, Utrecht, The Netherlands. cc.harts@mindef.nl
authors.forename: Chris C
authors.initials: CC
authors.lastname: Harts
authors.forename: Pieter H
authors.initials: PH
authors.lastname: Helmhout
authors.forename: Rob A
authors.initials: RA
authors.lastname: de Bie
authors.forename: J Bart
authors.initials: JB
authors.lastname: Staal
mesh_terms: D000293:Adolescent; D000328:Adult; D002908:Chronic Disease; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans; D017116:Low Back Pain / Q000628:therapy*; D008159:Lumbar Vertebrae; D053580:Muscle Strength; D005082:Physical Exertion; D016896:Treatment Outcome