Children's pedometer-determined physical activity during the segmented school day.

Purpose: To describe the sex-specific patterns of school children's daily pedometer-determined physical (PA) during physical education (PE), recess and lunchtime, and before and after school.

Methods: Eighty-one sixth-grade students (28 boys, age = 11.9 +/- 0.4 yr, BMI = 18.8 +/- 4.1 kg x m(-2); 53 girls, 11.8 +/- 0.5 yr, BMI = 20.2 +/- 4.6 kg x m(-2)) wore pedometers for four school days and were prompted to record steps accumulated at arrival and departure from school and during pre- and postrecess, lunchtime, and PE class.

Results: Boys took significantly (P < 0.001) more steps per day than girls: 16,421 +/- 5,444 vs 12,332 +/- 3,056 steps per day, and more steps during release time (e.g., before-school Delta = 1289 steps, recess Delta = 479 steps, lunchtime Delta = 608 steps, and after-school Delta = 1872 steps) but the same number of steps during structured PE classes (1429 +/- 567 vs 1410 +/- 445 steps; P = 0.87). Lunchtime PA represented the most important source of daily PA (15-16%) obtained during school hours for both boys and girls, whereas recess accounted for 8-9% and PE class accounted for 8-11% of total steps per day. Regardless, almost half of daily steps taken are attributable to after-school activities.

Conclusion: These data provide greater understanding of sex-specific PA patterns and the relative contribution of distinct segments of the school day to school children's total PA.