Frequency and intensity of activity of third-grade children in physical education.

Background: Health recommendations are for preadolescent children to have daily school physical education (PE) classes that engage children in moderate to vigorous physical activity at least 50% of class time.

Objective: To observe activity of children in PE classes in third grades across 10 different sites.

Design: Observational study.

Setting: Six hundred eighty-four elementary schools in 10 sites.

Subjects: A total of 814 children (414 boys, 400 girls; mean age, 9.0 years) enrolled in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development.

Methods: Each child was observed during 1 scheduled PE class.

Main Outcome Measure: The SOFIT (System for Observing Fitness Instruction Time) observation method, a validated, heart rate observation system, yields levels of activity the child is engaged in as well as the lesson context, type of teacher, and location of the PE class.

Results: Children averaged 2.1 PE lessons per week, of 33 minutes each. Only 5.9% of children had daily PE. Children accrued 4.8 very active and 11.9 minutes of moderate to vigorous physical activity per PE lesson, 15.0% and 37.0% of lesson time, respectively. Lesson length and number of minutes per week were similar for boys and girls; however, boys spent proportionately more PE time in very active and moderate to vigorous activity. This resulted in boys having a higher energy expenditure rate than girls.

Conclusion: Children observed in this study received 25 min/wk of moderate to vigorous activity in school PE, falling far short of national recommendations.