Using objective physical activity measures with youth: How many days of monitoring are needed?
Using objective physical activity measures with youth: How many days of monitoring are needed?
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DOI：
10.1097/00005768-200002000-00025
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发表时间：
2000-02-01
期刊：
影响因子：
--
通讯作者：
Taylor, WC
中科院分区：
文献类型：
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作者：
Trost, SG;Pate, RR;Taylor, WC
目的：本研究的目的是确定加速度计评估儿童日常体力活动所需的最少监测天数。方法：共有381名学生（189名男性，192名女性）连续7天佩戴CSA 7164单轴加速度计。为了研究与年龄有关的趋势，学生被分组如下：第一组：1-3年级（N = 92）;第二组：4-6年级（N = 98）;第三组：7-9年级（N = 97）;第四组：10-12年级（N = 94）。使用Freedson等人（1997）开发的回归方程，根据每分钟活动计数计算中重度体力活动（MVPA）的平均每日时间。结果：与7至12年级的青少年相比，1至6年级的儿童表现出较少的MVPA行为的日常变化。Spearman-Brown分析师指出，在儿童中需要4至5天的监测才能达到0.80的可靠性，在青少年中需要8至9天的监测才能达到0.80的可靠性。在所有年级水平内，7天监测方案产生了可接受的每日参与MVPA的估计值（R = 0.76（0.71-0.81）至0.87（0.84-0.90））。与平日相比，儿童表现出显着较高水平的MVPA在周末，而青少年表现出显着较低水平的MVPA在周末。主成分分析揭示了两个不同的时间成分MVPA在白天的儿童（清晨，休息的一天），和三个不同的时间成分MVPA在白天的青少年（上午，下午，傍晚）。结论：这些结果表明，7-d监测协议提供了可靠的估计，通常的身体活动行为的儿童和青少年，并占潜在的重要差异，周末与平日的活动行为，以及在给定的一天内的活动模式的差异。
Purpose: The purpose of this study was to establish the minimal number of days of monitoring required for accelerometers to assess usual physical activity in children. Methods: A total of 381 students (189 M, 192 F) wore a CSA 7164 uniaxial accelerometer for seven consecutive days. To examine age-related trends students were grouped as follows: Group I: grades 1-3 (N = 92); Group II: grades 4-6 (N = 98); Group III: grades 7-9 (N = 97); Group IV: grades 10-12 (N = 94). Average daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated from minute-by-minute activity counts using the regression equation developed by Freedson et al. (1997). Results: Compared with adolescents in grades 7 to 12, children in grades 1 to 6 exhibited less day-to-day variability in MVPA behavior. Spearman-Brown analysts indicated that between 4 and 5 d of monitoring would be necessary to a achieve a reliability of 0.80 in children, and between 8 and 9 d of monitoring would be necessary to achieve a reliability of 0.80 in adolescents. Within all grade levels, the 7-d monitoring protocol produced acceptable estimates of daily participation in MVPA (R = 0.76 (0.71-0.81) to 0.87 (0.84-0.90)). Compared with weekdays, children exhibited significantly higher levels of MVPA on weekends, whereas adolescents exhibited significantly lower levels of MVPA on weekends. Principal components analysis revealed two distinct time components for MVPA during the day for children (early morning, rest of the day), and three distinct time components for MVPA during the day for adolescents (morning, afternoon, early evening). Conclusions: These results indicate that a 7-d monitoring protocol provides reliable estimates of usual physical activity behavior in children and adolescents and accounts for potentially important differences in weekend versus weekday activity behavior as well as differences in activity patterns within a given day.