title: Validity of four short physical activity questionnaires in middle-aged persons.
abstract: OBJECTIVE
  Self-administered questionnaires continue to be the most widely used type of physical activity assessment in epidemiological studies. However, test-retest reliability and validity of physical activity questionnaires have to be determined. In this study, three short physical activity questionnaires already used in Switzerland and the International Physical Activity Questionnaire (IPAQ) were validated.
  
  
  METHODS
  Test-retest reliability was assessed by repeated administration of all questionnaires within 3 wk in 178 volunteers (77 women, 46.1+/-14.8 yr; 101 men 46.8+/-13.2 yr). Validity of categorical and continuous data was studied in a subsample of 35 persons in relation to 7-d accelerometer readings, percent body fat, and cardiorespiratory fitness.
  
  
  RESULTS
  Reliability was fair to good with a Spearman correlation coefficient range of 0.43-0.68 for measures of continuous data and moderate to fair with Kappa values between 0.32 and 0.46 for dichotomous measures active/inactive. Total physical activity reported in the IPAQ and the Office in Motion Questionnaire (OIMQ) correlated with accelerometry readings (r=0.39 and 0.44, respectively). In contrast, correlations of self-reported physical data with percent body fat and cardiorespiratory fitness were low (r=-0.26-0.29). Participants categorized as active by the Swiss HEPA Survey 1999 instrument (HEPA99) accumulated significantly more days of the recommended physical activities than their inactive counterparts (4.4 and 2.7 d.wk, respectively, P<0.05). However, compared with accelerometer data, vigorous physical activities were overreported in investigated questionnaires.
  
  
  CONCLUSIONS
  Collecting valid data on physical activity remains a challenging issue for questionnaire surveys. The IPAQ and the three other questionnaires are characterized to inform decisions about their appropriate use.
authors.affiliation: Federal Institute of Sports, Magglingen, Switzerland. urs.maeder@baspo.admin.ch
authors.forename: Urs
authors.initials: U
authors.lastname: Mäder
authors.forename: Brian W
authors.initials: BW
authors.lastname: Martin
authors.forename: Yves
authors.initials: Y
authors.lastname: Schutz
authors.forename: Bernard
authors.initials: B
authors.lastname: Marti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires; D013557:Switzerland