title: Reliability and validity of the global physical activity questionnaire in Vietnam.
abstract: BACKGROUND
  The Global Physical Activity Questionnaire (GPAQ) was developed as an improvement of the International Physical Activity Questionnaire (IPAQ) for use in cross-cultural settings. This study compared the reliability and validity of GPAQ and IPAQ in Vietnam.
  
  
  METHODS
  251 adults were randomly selected from a population-based survey (n = 1978) of noncommunicable disease risk factors. GPAQ and IPAQ were administered on 2 occasions. Participants wore pedometers and logged their physical activity (PA) for 7 consecutive days.
  
  
  RESULTS
  Test-retest correlations of GPAQ measurements differed for participants (n = 153) with stable work patterns (work PA r = .43, total PA r = .39) and those (n = 98) with unstable work patterns (work PA r = -0.02, total PA r = -0.05). IPAQ measurements did not differ in this way. GPAQ reliability was poorer for transport (GPAQ r = .25, IPAQ r = .60) and for leisure (GPAQ r = .21, IPAQ r = .45) PA. GPAQ estimates of total PA for participants with stable work patterns were moderately correlated with IPAQ total PA (r = .32), steps per day (r = .39), and PA log (r = .31).
  
  
  CONCLUSIONS
  The modifications made when designing GPAQ improved its reliability for persons with stable work patterns, but at the expense of poorer reliability for persons with more variable PA. GPAQ did not have superior validity to IPAQ.
authors.affiliation: Menzies Research Institute, University of Tasmania, Hobart, Australia.
authors.forename: Thuy Bich
authors.initials: TB
authors.lastname: Au
authors.forename: Leigh
authors.initials: L
authors.lastname: Blizzard
authors.forename: Michael
authors.initials: M
authors.lastname: Schmidt
authors.forename: Luc Hung
authors.initials: LH
authors.lastname: Pham
authors.forename: Costan
authors.initials: C
authors.lastname: Magnussen
authors.forename: Terence
authors.initials: T
authors.lastname: Dwyer
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D015203:Reproducibility of Results; D012307:Risk Factors; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D014744:Vietnam; D016138:Walking / Q000502:physiology*