Department of Epidemiology and Biostatistics, University of Maryland School of Public Health, College Park, Maryland 20742, USA.
J Adolesc Health. 2012 Dec;51(6):608-14. doi: 10.1016/j.jadohealth.2012.03.003. Epub 2012 Apr 12.
To examine "travel by walking" (TBW) before and after school among eighth-grade girls.
Participants attended 36 middle schools from Arizona, Maryland, Minnesota, Louisiana, California, and South Carolina participating in the Trial of Activity for Adolescent Girls. The cross-sectional sample consisted of 3,076 eighth-grade girls, and the longitudinal sample included 1,017 girls who participated in both sixth and eighth grades. Before- or after-school TBW status was determined from the 3-Day Physical Activity Recall. The main outcomes were body mass index and physical activity, which was measured by accelerometry, estimated for total physical activity (light, moderate, vigorous) and moderate-to-vigorous physical activity (MVPA).
Eighth-grade girls who reported TBW had 4 more minutes (95% confidence interval = 2.1-6.1) of MVPA before and after school than nonwalkers, and 2 more minutes of MVPA (95% confidence interval = 1.1-3.1) on an average weekday. In the longitudinal sample, girls who reported TBW before and after school in both sixth and eighth grades (consistent walkers) accumulated more minutes of MVPA for an average weekday than inconsistent walkers in both sixth (27 ± 2.2 vs. 25 ± 1.9 minutes; p = .03) and eighth (28 ± 2.6 vs. 25 ± 2.3 minutes; p = .003) grades. There were no differences in body mass index by walking status.
Adolescent girls who reported TBW before and after school accumulated more minutes of MVPA than nonwalkers. Efforts to prevent the decline in walking to school in middle school girls could contribute to their overall physical activity.
调查八年级女生上下学的“步行出行”（TBW）情况。
参与者来自亚利桑那州、马里兰州、明尼苏达州、路易斯安那州、加利福尼亚州和南卡罗来纳州的 36 所中学，他们参加了青少年女性活动试验。横断面样本由 3076 名八年级女生组成，纵向样本包括 1017 名同时参加六年级和八年级的女生。TBW 的上下学状态是根据 3 天体力活动回忆法确定的。主要结果是体重指数和体力活动，通过加速度计进行测量，用于估计总体力活动（轻、中、剧烈）和中到剧烈体力活动（MVPA）。
与非步行者相比，报告 TBW 的八年级女生上下学期间的 MVPA 多了 4 分钟（95%置信区间=2.1-6.1），在平均工作日多了 2 分钟的 MVPA（95%置信区间=1.1-3.1）。在纵向样本中，在六年级和八年级都报告 TBW 的女生（一致步行者）比六年级和八年级都报告不步行的女生（不一致步行者）在平均工作日积累了更多的 MVPA 分钟数，在六年级时分别为 27±2.2 分钟和 25±1.9 分钟（p=0.03），在八年级时分别为 28±2.6 分钟和 25±2.3 分钟（p=0.003）。步行状态与体重指数无差异。
报告上下学 TBW 的青少年女生比非步行者积累了更多的 MVPA 分钟数。防止中学女生步行上学人数下降的努力可能有助于她们整体的体力活动水平。
