By Lynn Gettleman Chehab, MD, MPH, Betsy Pfeffer MD, Rich Weil Med, and Shaofu Chen, MD, PhD.

Childhood obesity has reached epidemic proportions in the United States, where almost 17% of all children are obese (as defined by a body mass index greater than the 95th percentile on the Center for Diseases Control standardized growth charts developed in the 1970s). In New York City, children are even heavier: recent surveys by the New York Board of Education and the New York City Department of Health and Mental Hygiene found 24% of third-graders are obese, and another 19% are overweight (BMI >85th percentile).

Adolescence appears to be a crucial period in the development of adult obesity and a time when heavy adolescents become heavier. Adolescence is also associated with decreased physical activity for all youth. Almost half of 12-21 year olds are not engaged in regular vigorous physical activity. Multiple studies have shown that regular physical activity increases weight loss in overweight children and helps prevent weight gain in all children.

Currently, public schools in New York City are only required to provide physical education class two times a week, and most do so under very low budgets (less than $200 a year for equipment), and in cramped facilities that have not been updated in over 30 years. Only 5% of New York City public schools have outdoor playfields. Many schools have cut recess due to budget constraints, safety issues, and an increased focus on test preparation. Unsafe streets, family responsibilities, and lack of parental supervision often prevent children from exercising outside of school.

Our SEED grant funded a community project to increase the out-of-school physical activity of sixth grade students at Booker T. Washington Junior High School in Central Harlem. Students were predominantly African American and Latino who participated in the Charles Drew program for students who did not qualify for the honors program and were interested in Science. This program consists of two classrooms of approximately 30 students each. For 6 months, one of the classrooms received weekly 40 minute classes on individual activity and exercise from an exercise physiologist. These children were given weekly homework assignments to continue the exercises outside of school, for 60 minutes a day, most days of the week. The children had individual logs to record their activity and received small prizes for completing their homework. The other classroom served as a comparison group they received the same prizes, but no exercise classes or homework. Heights and weights of students in both classrooms were obtained at the beginning and end of the program.

Sixth grade children are still growing and are expected to gain an average of 3 pounds per year (which we defined as weight maintenance), and unfortunately, many children gain excessive weight during this period. Forty-eight percent of the children in the exercise class were able to maintain their weight (52% gained weight), compared to only 29% of a comparison classroom which received no exercise homework (70% gained weight). We found that only 30% of the students in the exercise class completed their exercise homework on a regular basis. The classroom teachers confirmed that these students were the same students who regularly completed their homework in their other classes. Of the third of the children who completed their homework regularly, 63% maintained their weight. (37% gained weight).

Focus groups with the students revealed many barriers to engaging in regular physical activity outside of school. Many children were responsible for caring for younger relatives after school. Others expressed that working parents were not able to escort them to and from recreation centers. Small and crowded apartments often prevented indoor exercising. Unsafe and busy streets were identified as barriers to neighborhood games and activities.

We found that our exercise program with homework was able to prevent excessive weight gain in children who completed their homework. Our final results and program will be made available to school physical education instructors and to the New York City Board of Education, who can incorporate these methods into their physical education curricula. Further investigation is necessary to examine the social constraints for regular physical activity. Given that so many children appear to have difficulty completing any homework, perhaps more activity needs to be regularly provided at school.

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