Physical activity during the transition from elementary school to high school

描述：体育锻炼对儿童和青少年的健康有重要的益处。然而，目前，随着儿童进入青春期，体力活动水平显著下降，很少有美国高中生符合当前的体力活动指南。拟议的研究(Track-2)将扩展现有的观察性队列研究(Track-1)，以确定解释儿童从小学过渡到初中再到高中时体力活动发生变化的显著因素。这项研究的主要目标是为未来的体力活动干预措施提供信息，并扩大关于体力活动与选定的健康指标之间的关系的知识范围，包括儿童和青少年时期的身体肥胖。具体目标包括1)确定影响青少年从小学过渡到高中的与年龄相关的体育活动轨迹的个人、社会环境和身体环境因素； 2)描述青少年从小学到高中的体力活动、久坐行为和体重状况指标之间的纵向关系；3)描述高中生在儿童期和青春期纵向观察的体力活动与选定的健康指标之间的关系。这项研究将在大约850名9年级和11年级的学生以及他们的家长、学校和社区中测量同一学生在5年级、6年级和7年级测量的所有变量，包括通过加速计测量的体力活动。其他与高中生相关的变量也将被测量。这些变量中的三个--睡眠、健康和学业成绩--将在10年级时在队列的子样本中进行测量。这项拟议的研究具有重要意义，因为它将确定潜在的因素 与年龄相关的体力活动变化，为设计有效的公共卫生干预措施提供必要的知识，以增加美国儿童和青年的体力活动和预防肥胖。这项研究具有创新性，因为它将是第一个跟踪规模较大且不同的队列的研究 在美国青少年从小学过渡到初中再到高中的过程中，将使用多层次模型来检验一组全面和仔细测量的体力活动变化的潜在预测因素。

DESCRIPTION: Physical activity provides important health benefits to children and adolescents. Currently, however, physical activity levels decline significantly as children progress into adolescence, and few U.S. high school students meet current physical activity guidelines. The proposed study (TRACK-2) will extend an existing observational cohort study (TRACK-1) to identify salient factors that explain the changes in physical activity that occur as children transition from elementary school through middle school and into high school. Major goals of the study are to inform future physical activity interventions and to expand the body of knowledge regarding the relationship between physical activity and selected health indicators, including body fatness, during childhood and adolescence. The specific aims include 1)To identify personal, social environmental and physical environmental factors that influence the age-related trajectory for physical activity in youth as they transition from elementary school to high school; 2) To describe the longitudinal associations among physical activity, sedentary behavior and measures of body weight status in youth as they transition from elementary school to high school; and 3) To describe the relationship between physical activity, observed longitudinally during childhood and adolescence, and selected health indicators in high school students. The study will measure in approximately 850 9th and 11th grade students, as well as their parents, schools and communities, all of the variables that were measured in the same students in 5th, 6th and 7th grades, including physical activity measured by accelerometry. Additional variables that are relevant for high school students also will be measured. Three of these variables - sleep, fitness and academic achievement - will be measured in a sub- sample of the cohort in 10th grade. The proposed research is significant because it will identify the factors that underlie age-related changes in physical activity, providing knowledge needed to design effective public health interventions to increase physical activity and prevent obesity in American children and youth. The study is innovative because it will be the first to follow a sizeable and diverse cohort of American youth as it transitions from elementary school through middle school and into high school and will use multi-level modeling to examine a comprehensive and carefully-measured set of potential predictors of change in physical activity.