Trost Stewart G, Rosenkranz Richard R, Dzewaltowski David
Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97333, USA.
Med Sci Sports Exerc. 2008 Apr;40(4):622-9. doi: 10.1249/MSS.0b013e318161eaa5.
To describe the physical activity (PA) levels of children attending after-school programs, 2) examine PA levels in specific after-school sessions and activity contexts, and 3) evaluate after-school PA differences in groups defined by sex and weight status.
One hundred forty-seven students in grades 3-6 (mean age: 10.1 +/- 0.7, 54.4% male, 16.5 % overweight (OW), 22.8% at-risk for OW) from seven after-school programs in the midwestern United States wore Actigraph GT1M accelerometers for the duration of their attendance to the program. PA was objectively assessed on six occasions during an academic year (three fall and three spring). Stored activity counts were uploaded to a customized data-reduction program to determine minutes of sedentary (SED), light (LPA), moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) physical activity. Time spent in each intensity category was calculated for the duration of program attendance, as well as specific after-school sessions (e.g., free play, snack time).
On average, participants exhibited 42.6 min of SED, 40.8 min of LPA, 13.4 min of MPA, and 5.3 min of VPA. The average accumulation of MVPA was 20.3 min. Boys exhibited higher levels of MPA, VPA, and MVPA, and lower levels of SED and LPA, than girls. OW and at-risk-for-OW students exhibited significantly less VPA than nonoverweight students, but similar levels of LPA, MPA, and MVPA. MVPA levels were significantly higher during free-play activity sessions than during organized or structured activity sessions.
After-school programs seem to be an important contributor to the PA of attending children. Nevertheless, ample room for improvement exists by making better use of existing time devoted to physical activity.
1）描述参加课外项目的儿童的身体活动（PA）水平，2）研究特定课外时段和活动环境中的PA水平，3）评估按性别和体重状况划分的组间课外PA差异。
来自美国中西部七个课外项目的147名三至六年级学生（平均年龄：10.1±0.7岁，54.4%为男性，16.5%超重（OW），22.8%有超重风险）在参加项目期间佩戴Actigraph GT1M加速度计。在一学年内分六次（秋季三次，春季三次）客观评估PA。将存储的活动计数上传到定制的数据简化程序中，以确定久坐（SED）、轻度（LPA）、中度（MPA）、剧烈（VPA）和中度至剧烈（MVPA）身体活动的分钟数。计算参加项目期间以及特定课外时段（如自由活动、吃零食时间）在每个强度类别中花费的时间。
平均而言，参与者的久坐时间为42.6分钟，轻度身体活动时间为40.8分钟，中度身体活动时间为13.4分钟，剧烈身体活动时间为5.3分钟。MVPA的平均累计时间为20.3分钟。男孩比女孩表现出更高水平的MPA、VPA和MVPA，以及更低水平的SED和LPA。超重和有超重风险的学生比非超重学生表现出显著更少的VPA，但LPA、MPA和MVPA水平相似。自由活动时段的MVPA水平显著高于有组织或结构化活动时段。
课外项目似乎是参加项目儿童PA的重要贡献因素。然而，通过更好地利用现有的体育活动时间，仍有很大的改进空间。
