2013 Annual Report
1a.Objectives (from AD-416):
Objective 1: No longer applies
Objective 2: Develop and pilot test interventions to increase and sustain physical activity at a level consistent with the Dietary Guidelines for Americans (DG) in urban African- and Mexican-American children. Sub-objective 2A: Determine if adherence to the physical activity component of the DG is associated with a lower incidence of overweight/obesity in urban African- and Mexican-American children. Sub-objective 2B: Develop and pilot test an intervention with urban African- and Mexican-American children to increase physical activity consistent with the DG recommendation. Specifically, physical activity will be operationally defined as moderate to vigorous physical activity. Sub-objective 2C: Develop and pilot test a maintenance program with urban African- and Mexican-American children to sustain physical activity consistent with the DG recommendation. Specifically, physical activity will be operationally defined as moderate to vigorous physical activity.
1b.Approach (from AD-416):
A sample of 200 African- or Mexican-American middle school children (i.e., 6th – 8th grade; aged 10-15 years will be recruited from a Houston charter school to provide data on their participation in moderate to vigorous physical activity (MVPA). Measured body composition (i.e., height, weight, BMI, percent body fat) will be collected. This study will examine children's free-living participation in physical activity (PA) to determine if these behaviors are consistent with the Dietary Guidelines for Americans (DG) (i.e., 60 minutes of MVPA most days of the week). A questionnaire will be administered identifying PA barriers and facilitators to help determine activities most likely to encourage continued participation in PA. Subjects will be assessed to determine their level of adherence to PA that is consistent with the DG.
Children's Nutrition Research Center researchers found similar results for the second phase participants as with the first phase participants. We assessed the level of physical activity for 100 phase two participants (for sub-objective 2B) using accelerometry. During weekdays (Monday through Friday) participants engaged in moderate to vigorous physical activity for 44 minutes on average. During weekends (Saturday and Sunday) they engaged in moderate to vigorous physical activity for 55 minutes on average. Only 3% of the participants met dietary guidelines recommendations for 60 minutes of physical activity during weekdays, and 5% of the participants met dietary guidelines recommendations during weekends. While few children are meeting the full recommendation of 60 minutes of physical activity per day, the average number of minutes of physical activity suggests that children are approximating the goal, particularly on weekends. It appears that greater efforts are needed to increase physical activity during the weekdays when children are in school. We analyzed body composition data, and the results revealed that while the level of moderate to vigorous physical activity was not related to standardized body mass index (zBMI), participation in hard to very hard physical activity decreased as zBMI and percent body fat increased.
A sample of 200 students have been recruited to participate in a physical activity intervention. In order to meet dietary guidelines recommendations of 60 minutes of physical activity daily, this intervention was aimed at increasing moderate to vigorous physical activity in the participants. This intervention was also shown to significantly reduce the rate of weight gain. Additionally, data regarding the barriers and facilitators to physical activity were collected from this group of participants. Homework and a preference to watch television were reported as the most common barriers to physical activity. Due to these barriers, the intervention was modified to increase physical activity during the school day and gradually decrease time spent watching television, playing videogames, and being on the computer. Students who received the intervention increased their participation in moderate to vigorous physical activity. A sample of 100 students from objective 2B (for sub-objective 2C) were recruited to participate in a follow-up program designed to maintain increased levels of physical activity long term. We are in the process of collecting data regarding the maintenance of these increased levels of physical activity over this 3-year period.
Minority children meet Dietary Guidelines for physical activity. The current dietary guidelines recommend that children engage in 60 minutes of physical activity daily. However, children are engaging in considerably less physical activity now than they were 20 years ago, and this decrease coincides with increased prevalence of obesity in youth. Scientists at the Children's Nutrition Research Center in Houston, Texas, have developed a program to increase physical activity in children in order to meet dietary guideline recommendations for physical activity. We were able to demonstrate that the participants of the treatment group not only improved their physical activity levels but also maintained these levels over time. This is particularly important for minority children who are at greater risk for obesity-related health problems. These results have important implications for future policy development.