This study measured students’ free-living Physical Activity (PA) in order to examine activity patterns of youth. Students (N=221) in 12-classes wore accelerometers to measure their PA over six weeks in and out-of-school while participating in a fitness unit. PA was significantly higher during Non-PE-Days and PE-Days than on Sundays. PA was significantly higher during baseline than weeks five and six. There were no significant differences between boys and girls in the number steps taken. Eighth-grade students had the lowest PA levels. On average, the students were attaining 60 minutes of MVPA. Students, however, did not often reach national recommendations. Girls reached their national recommendations five out of six weeks on days that they participated in PE. The results suggest that specific subgroups, such as adolescent girls, are getting the recommended PA but only when the PA is structured. A spike in PA during the first week suggested a possible motivational effect of the accelerometer.

中文翻译：

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在体育日，非体育日和周末中学生的自由生活体育活动

这项研究测量了学生的自由活动体育活动（PA），以检查青少年的活动模式。参加健身课的12个班级的学生（N = 221）穿着加速度计在六周内和校外测量其PA。非体育节和体育节期间的PA明显高于周日。在基线期间，PA显着高于第五和第六周。男孩和女孩在步数上没有显着差异。八年级学生的PA水平最低。平均而言，学生获得了60分钟的MVPA。但是，学生并不经常达到国家建议。在参加体育运动的六天内，女孩达到了六分之五的国家建议。结果表明，特定的亚组，例如少女，仅在结构化PA的情况下才能获得推荐的PA。在第一周PA的峰值表明加速度计可能具有激励作用。