title: Reliability and validity of the 6-min walk test in adults and seniors with intellectual disabilities.
abstract: BACKGROUND
  Adults with intellectual disabilities (ID) have significantly lower rates of physical activity and fitness than adults without ID. The 6-min walk test (6 MWT) is an inexpensive and simple way to test mobility and submaximal work capacity.
  
  
  OBJECTIVE
  To evaluate the test-retest reliability and validity of the 6 MWT in adults and seniors with ID and explore factors contributing to the 6 MWT distance (6 MWD).
  
  
  METHODS
  46 participants with mild, moderate and severe ID levels (age=41 ± 11 years) performed the 6 MWT three times (T1; T2; T3) to determine test-retest reliability. To test validity, peak oxygen uptake (VO2 peak) was measured using a treadmill protocol. To analyze factors contributing to the 6 MWD, sex, height, fat mass % and fat free mass %, ID level, isometric leg strength and relative VO2 peak were also measured.
  
  
  RESULTS
  The walking distances for T1, T2 and T3 were 460.3 ± 76.9; 489.4 ± 81.2 and 491.4 ± 77.9 m, respectively. The 6 MWDs between T1-T2 and T1-T3 were significantly different (p<0.001), but T2 and T3 were not different. The intraclass correlation coefficient between T2 and T3 was 0.96 indicating high reliability. Relative VO2 peak and isometric leg strength significantly contributed to the 6 MWD (R(2)=0.55).
  
  
  CONCLUSIONS
  The 6 MWT is an easy, inexpensive, reliable and valid test in adults and seniors with ID. Familiarization is necessary to obtain reliable values. Relative VO2 peak and leg strength have significant impact on the distance walked.
authors.affiliation: FPCEE-Blanquerna, University Ramon Llull, c/ Cister 34, Barcelona 08022, Spain. Electronic address: miriamelisagb@blanquerna.url.edu.
authors.forename: Myriam
authors.initials: M
authors.lastname: Guerra-Balic
authors.affiliation: FPCEE-Blanquerna, University Ramon Llull, c/ Cister 34, Barcelona 08022, Spain; School of Biokinetics, Recreation and Sport Science, North-West University (Potchefstroom Campus), Private Bag X 6001, Potchefstroom 2520, South Africa. Electronic address: guilermorubeno@blanquerna.url.edu.
authors.forename: Guillermo R
authors.initials: GR
authors.lastname: Oviedo
authors.affiliation: Department of Physiological Sciences II, School of Medicine, University of Barcelona, Feixa Llarga Street, L'Hospitalet del Llobregat 08907, Spain. Electronic address: cjavierre@ub.edu.
authors.forename: Casimiro
authors.initials: C
authors.lastname: Javierre
authors.affiliation: FPCEE-Blanquerna, University Ramon Llull, c/ Cister 34, Barcelona 08022, Spain. Electronic address: jesusfg@blanquerna.url.edu.
authors.forename: Jesús
authors.initials: J
authors.lastname: Fortuño
authors.affiliation: FPCEE-Blanquerna, University Ramon Llull, c/ Cister 34, Barcelona 08022, Spain. Electronic address: silviabl0@blanquerna.url.edu.
authors.forename: Silvia
authors.initials: S
authors.lastname: Barnet-López
authors.affiliation: Department of Physiological Sciences II, School of Medicine, University of Barcelona, Feixa Llarga Street, L'Hospitalet del Llobregat 08907, Spain. Electronic address: oninomen9@alumnes.ub.edu.
authors.forename: Oscar
authors.initials: O
authors.lastname: Niño
authors.affiliation: Department of Physiological Sciences II, School of Medicine, University of Barcelona, Feixa Llarga Street, L'Hospitalet del Llobregat 08907, Spain. Electronic address: jalamopi7@alumnes.ub.ed.
authors.forename: Juan
authors.initials: J
authors.lastname: Alamo
authors.affiliation: Department of Kinesiology and Nutrition, University of Illinois at Chicago, 1919 West Taylor Street, Chicago, IL 60612, USA. Electronic address: fernhall@uic.edu.
authors.forename: Bo
authors.initials: B
authors.lastname: Fernhall
mesh_terms: D000328:Adult; D000368:Aged; D005080:Exercise Test; D005260:Female; D006801:Humans; D008607:Intellectual Disability; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D010101:Oxygen Consumption; D010809:Physical Fitness; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Adults; Intellectual disability; Reliability; Seniors; Six-minute walk test; Validity