Compliance with wearing physical activity accelerometers in high school students.
BACKGROUND
Accelerometer use in physical activity research has become increasingly popular but is prone to problems with missing data, which complicate the data reduction and analysis process. The purpose of this study was to determine the effect of hypothesized compliance strategies on improving compliance with wearing a physical activity accelerometer in high school students.


METHODS
Each of four local high schools was assigned to one of four compliance strategies: (1) receiving three phone calls, (2) completing a daily journal, (3) compensation contingent on number of complete (> or = 10 hours) days of data, and (4) control condition. Participants wore ActiGraph accelerometers for seven days to determine compliance and physical activity.


RESULTS
The contingent group had the highest level of compliance with 96% of the participants acquiring at least four of seven complete days of data. After controlling for grade level, school level percent minority students, and school level socioeconomic status (SES), the contingent group's compliance remained significantly higher (P = .04) than the journal (85%), phone (72%), and control (70%) participants.


CONCLUSIONS
The contingent compliance strategy improved the amount of time the students wore the monitor each day and, thus, the total number of days with > or =10 hours of data.
Sirard
John R
JR
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
Slater
Megan E
ME
D056044:Actigraphy; D000293:Adolescent; D015444:Exercise; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008499:Medical Records; D008910:Minnesota; D010349:Patient Compliance / Q000208:ethnology; D017010:Reminder Systems; D012201:Reward; D013334:Students; D013689:Telephone