Pedometer-determined physical activity levels of adolescents: differences by age, sex, time of week, and transportation mode to school.

Background: Few studies have examined high school students' physical activity habits using objective measures. The purpose of this study was to describe pedometer-determined habitual physical activity levels of youth.

Methods: 236 high school students (age 12-18 years) wore sealed pedometers for 5 consecutive days. Data were analyzed using generalizing estimating equations.

Results: Mean steps/d (+/- SE) differed significantly by sex (males, 10,849 (+/- 381; females, 9652 (+/- 289), age (junior students [years 9-11], 11,079 (+/- 330; senior students [years 12 and 13], 9422 (+/- 334), time of week (weekday, 12,259 (+/- 287; weekend day, 8241 (+/- 329), and mode of transportation to and from school (walkers, 13,308 (+/- 483; car transit users, 10,986 (+/- 435). Only 14.5% of students achieved at least 10,000 steps on every day during the monitoring period.

Conclusion: Daily step counts differed substantially by age, sex, time of week, and transportation mode to school.