Department of Pediatrics, Yale School of Medicine, New Haven, CT 06520-8064, USA.
Res Q Exerc Sport. 2009 Sep;80(3):460-8. doi: 10.1080/02701367.2009.10599584.
This cross-sectional study using direct motion monitoring evaluated whether short epochs increased estimates of moderate or vigorous physical activity (MPA or VPA) and enhanced differences in daily VPA comparing overweight (OW) and nonoverweight (NOW) children. Seventy-seven children (ages 8-10 years) wore accelerometers for 7 days. We calculated two estimates (mean minutes per day) of MPA and VPA using motion counts based on a 15-s epoch and a calculated 60-s epoch produced by totaling each consecutive group of four 15-s motion counts. We compared estimates as a function of mean motion count x min(-1) for sex, age, and status as OW or NOW. The results showed that a 15-s epoch produced higher estimates of VPA (mean difference of 7 min per day, p < .001). The average number of VPA minutes added using the 15-s epoch vs. the 60-s epoch was 8.8 for more active children compared with 5.8 for less active children (p < .001). There was no difference in VPA minutes between OW and NOW children. These findings suggest modestly increased sensitivity to VPA using shorter epochs; this was particularly true for the most active children. Shorter epochs, however might not be useful in clarifying the relationship between VPA and obesity in children.
本横断面研究采用直接运动监测评估了短时间间隔是否会增加对中度或剧烈体力活动（MPA 或 VPA）的估计，并增强了超重（OW）和非超重（NOW）儿童之间日常 VPA 的差异。77 名儿童（8-10 岁）佩戴加速度计 7 天。我们使用基于 15 秒时间间隔的运动计数和通过累计每组连续的 4 个 15 秒运动计数计算的 60 秒时间间隔计算了 MPA 和 VPA 的两个估计值（每天平均分钟数）。我们比较了性别、年龄和 OW 或 NOW 状态作为函数的估计值。结果表明，15 秒时间间隔产生了更高的 VPA 估计值（每天平均差异为 7 分钟，p <.001）。与使用 60 秒时间间隔相比，使用 15 秒时间间隔添加的 VPA 分钟数平均增加了 8.8 分钟，对于更活跃的儿童为 5.8 分钟（p <.001）。OW 和 NOW 儿童之间的 VPA 分钟数没有差异。这些发现表明，使用较短的时间间隔，VPA 的敏感性略有提高；对于最活跃的儿童来说尤其如此。然而，较短的时间间隔可能无助于澄清 VPA 与儿童肥胖之间的关系。
