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Open Access Research

Pedometer determined physical activity tracks in African American adults: The Jackson Heart Study

Robert L Newton1, Hongmei Han M1, Patricia M Dubbert234, William D Johnson1, DeMarc A Hickson56, Barbara Ainsworth7, Teresa Carithers8, Herman Taylor5, Sharon Wyatt5 and Catrine Tudor-Locke1*

Author Affiliations

1 Pennington Biomedical Research Center, Baton Rouge, LA, USA

2 South Central VA Mental Illness Research Education & Clinical Center, Little Rock, AR, USA

3 Little Rock Geriatric Research Education & Clinical Center, Little Rock, AR, USA

4 Psychiatric Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA

5 Jackson State University, Jackson, MS, USA

6 University of Mississippi Medical Center, Jackson, MS, USA

7 Arizona State University, Phoenix, AZ, USA

8 University of Mississippi, University, Mississippi, MS, USA

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International Journal of Behavioral Nutrition and Physical Activity 2012, 9:44  doi:10.1186/1479-5868-9-44

Published: 18 April 2012

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.

Conclusion

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.

Keywords:
Physical activity assessment; African Americans; Sedentary; Validity