title: Six-minute walk test versus two-minute walk test in children with Duchenne muscular dystrophy: Is more time more information?
abstract: OBJECTIVE
  The six minute walk test is a widely accepted primary outcome parameter in most studies in Duchenne muscular dystrophy (DMD). To compare information obtained by the six minute walk distance (6MWD) test and the two minute walk distance (2MWD) in patients with DMD, a cohort of 13 voluntary DMD boys did a repeated six minute walking test.
  
  
  METHODS
  Patients had to be ambulatory with a physical disability according to Levels 1-3 on the Vignos-Scale for lower extremity. Measurements were taken at one minute intervals. Reliability was measured by intraclass correlation.
  
  
  RESULTS
  Test-retest reliability for 6MWD and 2MWD in two different age classes was very good for both subgroups. Test-retest-reliability was lower in patients with more advanced disability in both tests. Walking speed remained completely stable from time points 1-6 minutes in the whole study patient collective, which indicates that physical exhaustion is not reached after six minutes even in more disabled patients.
  
  
  CONCLUSIONS
  Thus the 6MWD in DMD patients does not give additional information as compared to a 2MWD.
authors.affiliation: Department of Pediatric Neurology and Developmental Medicine, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany. Electronic address: katharina.vill@med.uni-muenchen.de.
authors.forename: Katharina
authors.initials: K
authors.lastname: Vill
authors.affiliation: Department of Pediatric Neurology and Developmental Medicine, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany. Electronic address: lena.ille@web.de.
authors.forename: Lena
authors.initials: L
authors.lastname: Ille
authors.affiliation: Department of Pediatric Neurology and Developmental Medicine, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany. Electronic address: sebastian.schroeder@med.uni-muenchen.de.
authors.forename: Sebastian A
authors.initials: SA
authors.lastname: Schroeder
authors.affiliation: Department of Pediatric Neurology and Developmental Medicine, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany. Electronic address: astrid.blaschek@med.uni-muenchen.de.
authors.forename: Astrid
authors.initials: A
authors.lastname: Blaschek
authors.affiliation: Department of Pediatric Neurology and Developmental Medicine, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany. Electronic address: wolfgang.mueller-felber@med.uni-muenchen.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Müller-Felber
mesh_terms: D002648:Child; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000175:diagnosis*; D017063:Outcome Assessment, Health Care; D015203:Reproducibility of Results; D013997:Time Factors; D016138:Walking
keywords: Duchenne muscular dystrophy; Outcome measures; Six minute walk test; Test–retest reliability; Two minute walk test