National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30345, USA.
Med Sci Sports Exerc. 2011 Nov;43(11):2140-7. doi: 10.1249/MSS.0b013e31821f561a.
This study aimed to characterize longitudinal age trajectories across 5 yr in the prevalence of free-time and organized physical activity participation among US youth by sex, race, and parental education.
Study participants were a nationally representative sample of youth, 9-13 yr old in 2002, who participated in the Centers for Disease Control and Prevention's Youth Media Campaign Longitudinal Survey. Baseline data were collected in 2002. Attrition for the next 4 yr resulted in an overall response rate of 23% by 2006 (n = 1623). The survey collected information concerning respondents' frequency of participation in free-time and organized physical activities outside school. Organized activities were defined as activities involving a coach, instructor, or other leader. Orthogonal polynomial contrasts were used to test for linear and quadratic trends in respondents' participation free-time and organized physical activity sessions during the previous 7 d over ages 9-17. Pairwise t-tests were used to determine whether age-specific estimates of participation rates differed significantly by sex, race, and parental education level.
Free-time physical activity participation prevalence declined linearly from ages 9 to 17 in both sexes but also demonstrated a quadratic trajectory in boys, peaking at age 13. Organized physical activity demonstrated a quadratic trajectory and declined most notably after age 14 in both sexes. Free-time physical activity participation was lower in girls compared with boys between ages 12 and 16 (difference range = 12-17 percentage points). Both non-white youth and those with less educated parents had lower organized physical activity participation at most ages (difference range = 15-29 percentage points).
Free-time and organized physical activity exhibit different trajectories between ages 9 and 17 and are subject to dissimilar demographic level variation.
本研究旨在通过性别、种族和父母受教育程度来描述美国青少年在 5 年内自由时间和有组织体育活动参与率的纵向年龄轨迹。
研究参与者为全国代表性的青少年样本，2002 年年龄为 9-13 岁，参加了疾病控制与预防中心的青少年媒体运动纵向调查。基线数据于 2002 年收集。在接下来的 4 年中，由于流失，到 2006 年总体应答率为 23%（n=1623）。该调查收集了有关受访者在学校外参加自由时间和有组织体育活动的频率的信息。有组织的活动是指涉及教练、指导员或其他领导者的活动。使用正交多项式对比来检验受访者在过去 7 天内参加自由时间和有组织体育活动的频率在 9-17 岁期间的线性和二次趋势。使用配对 t 检验来确定特定年龄的参与率是否因性别、种族和父母受教育程度的不同而有显著差异。
在男女两性中，自由时间体育活动参与率从 9 岁到 17 岁呈线性下降，但在男孩中也表现出二次轨迹，在 13 岁时达到峰值。有组织的体育活动表现出二次轨迹，在两性中，14 岁后下降最为明显。在 12-16 岁之间，女孩的自由时间体育活动参与率低于男孩（差异范围为 12-17 个百分点）。非白人和父母受教育程度较低的青少年在大多数年龄段的组织体育活动参与率较低（差异范围为 15-29 个百分点）。
自由时间和有组织的体育活动在 9-17 岁之间呈现出不同的轨迹，并且受到不同的人口统计学水平变化的影响。
