title: How sustainable is strength training in chronic obstructive pulmonary disease?
abstract: OBJECTIVE
  To examine whether the benefits from strength training are sustained after an initial training period in patients with chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  MEDLINE (1966 to May 2008), CENTRAL (1948 to May 2008) and PEDro (1929 to May 2008).
  
  
  METHODS
  Criteria for inclusion in this review were that study participants had COPD and undertook an intervention that included strength training. A period of follow-up (>/=12 weeks) after strength training and a measure of muscle strength taken at this time were required. All experimental study designs were accepted, and the publication language had to be English. Reviews were excluded. The PEDro scale was used to assess the methodological quality of studies.
  
  
  RESULTS
  Only three eligible studies were identified (PEDro scores ranged from 5 to 7). Two studies found that the benefits from strength training were still evidental at 12 weeks and 12 months after an initial 12-week and 6-month training period, respectively. The other study found no difference between the control and training groups 12 weeks after a 12-week training intervention. Only one study discussed continuation of strength training during the follow-up period. The results of these studies could not be pooled for meta-analysis, as the study interventions and assessments were heterogeneous.
  
  
  CONCLUSIONS
  Despite an extensive search of the literature, only three articles were identified. Therefore, the long-term effects of strength training remain unknown. Further trials examining the sustainability of strength training with homogeneous populations, training programmes and assessments are warranted. This would enable the pooling of results for meta-analysis, and provide clearer recommendations to pulmonary rehabilitation practitioners.
authors.affiliation: Pulmonary Rehabilitation Research Group, Glenfield Hospital, University Hospitals of Leicester NHS Trust, Leicester LE3 9QP, UK. Linzy.Houchen@uhl-tr.nhs.uk
authors.forename: Linzy
authors.initials: L
authors.lastname: Houchen
authors.forename: Michael C
authors.initials: MC
authors.lastname: Steiner
authors.forename: Sally J
authors.initials: SJ
authors.lastname: Singh
mesh_terms: D017079:Exercise Tolerance / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000628:therapy*; D055070:Resistance Training