title: Pedometer determined physical activity tracks in African American adults: the Jackson Heart Study.
abstract: BACKGROUND
  This study investigated the number of pedometer assessment occasions required to establish habitual physical activity in African American adults.
  
  
  METHODS
  African American adults (mean age 59.9 ± 0.60 years; 59 % female) enrolled in the Diet and Physical Activity Substudy of the Jackson Heart Study wore Yamax pedometers during 3-day monitoring periods, assessed on two to three distinct occasions, each separated by approximately one month. The stability of pedometer measured PA was described as differences in mean steps/day across time, as intraclass correlation coefficients (ICC) by sex, age, and body mass index (BMI) category, and as percent of participants changing steps/day quartiles across time.
  
  
  RESULTS
  Valid data were obtained for 270 participants on either two or three different assessment occasions. Mean steps/day were not significantly different across assessment occasions (p values > 0.456). The overall ICCs for steps/day assessed on either two or three occasions were 0.57 and 0.76, respectively. In addition, 85 % (two assessment occasions) and 76 % (three assessment occasions) of all participants remained in the same steps/day quartile or changed one quartile over time.
  
  
  CONCLUSIONS
  The current study shows that an overall mean steps/day estimate based on a 3-day monitoring period did not differ significantly over 4 - 6 months. The findings were robust to differences in sex, age, and BMI categories. A single 3-day monitoring period is sufficient to capture habitual physical activity in African American adults.
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA, USA. Catrine.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Newton
authors.forename: Hongmei Han
authors.initials: HH
authors.lastname: M
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Dubbert
authors.forename: William D
authors.initials: WD
authors.lastname: Johnson
authors.forename: DeMarc A
authors.initials: DA
authors.lastname: Hickson
authors.forename: Barbara
authors.initials: B
authors.lastname: Ainsworth
authors.forename: Teresa
authors.initials: T
authors.lastname: Carithers
authors.forename: Herman
authors.initials: H
authors.lastname: Taylor
authors.forename: Sharon
authors.initials: S
authors.lastname: Wyatt
authors.forename: Catrine
authors.initials: C
authors.lastname: Tudor-Locke
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000628:therapy; D004032:Diet; D005260:Female; D015438:Health Behavior; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011795:Surveys and Questionnaires; D055815:Young Adult