Movement Behaviours, Nutrition, Health, & Wellbeing Research Group, and Department of Sport & Physical Activity, Edge Hill University, Ormskirk, UK.
Diabetes Research Centre, Leicester General Hospital, University of Leicester, Leicester, UK.
Int J Behav Nutr Phys Act. 2023 Mar 25;20(1):35. doi: 10.1186/s12966-023-01435-z.
Over the last decade use of raw acceleration metrics to assess physical activity has increased. Metrics such as Euclidean Norm Minus One (ENMO), and Mean Amplitude Deviation (MAD) can be used to generate metrics which describe physical activity volume (average acceleration), intensity distribution (intensity gradient), and intensity of the most active periods (MX metrics) of the day. Presently, relatively little comparative data for these metrics exists in youth. To address this need, this study presents age- and sex-specific reference percentile values in England youth and compares physical activity volume and intensity profiles by age and sex.
Wrist-worn accelerometer data from 10 studies involving youth aged 5 to 15 y were pooled. Weekday and weekend waking hours were first calculated for youth in school Years (Y) 1&2, Y4&5, Y6&7, and Y8&9 to determine waking hours durations by age-groups and day types. A valid waking hours day was defined as accelerometer wear for ≥ 600 min·d and participants with ≥ 3 valid weekdays and ≥ 1 valid weekend day were included. Mean ENMO- and MAD-generated average acceleration, intensity gradient, and MX metrics were calculated and summarised as weighted week averages. Sex-specific smoothed percentile curves were generated for each metric using Generalized Additive Models for Location Scale and Shape. Linear mixed models examined age and sex differences.
The analytical sample included 1250 participants. Physical activity peaked between ages 6.5-10.5 y, depending on metric. For all metrics the highest activity levels occurred in less active participants (3-50 percentile) and girls, 0.5 to 1.5 y earlier than more active peers, and boys, respectively. Irrespective of metric, boys were more active than girls (p < .001) and physical activity was lowest in the Y8&9 group, particularly when compared to the Y1&2 group (p < .001).
Percentile reference values for average acceleration, intensity gradient, and MX metrics have utility in describing age- and sex-specific values for physical activity volume and intensity in youth. There is a need to generate nationally-representative wrist-acceleration population-referenced norms for these metrics to further facilitate health-related physical activity research and promotion.
在过去十年中，使用原始加速度指标来评估身体活动的情况有所增加。欧几里得范数减一 (ENMO) 和平均幅度差 (MAD) 等指标可用于生成描述身体活动量（平均加速度）、强度分布（强度梯度）和一天中最活跃时期强度 (MX 指标) 的指标。目前，这些指标在年轻人中的比较数据相对较少。为了解决这一需求，本研究提供了英格兰年轻人特定年龄和性别的参考百分位数值，并比较了按年龄和性别划分的身体活动量和强度分布。
汇总了涉及 5 至 15 岁青少年的 10 项研究的腕戴式加速度计数据。首先计算了在校年（Y）1&2、Y4&5、Y6&7 和 Y8&9 中青少年的工作日和周末清醒时间，以确定按年龄组和日类型划分的清醒时间持续时间。定义有效的清醒时间天数为佩戴加速度计 ≥ 600 分钟·天，且参与者至少有 3 个有效工作日和 1 个有效周末天。计算了平均 ENMO 和 MAD 生成的平均加速度、强度梯度和 MX 指标，并作为加权周平均值进行总结。使用广义加性模型进行位置、比例和形状的性别特异性平滑百分位曲线生成。线性混合模型检查了年龄和性别差异。
分析样本包括 1250 名参与者。身体活动量在 6.5-10.5 岁之间达到峰值，具体取决于指标。对于所有指标，最高活动水平出现在活动水平较低的参与者（第 3-50 百分位）和女孩中，比更活跃的同龄人早 0.5 至 1.5 岁，比男孩早。无论指标如何，男孩都比女孩更活跃（p<0.001），Y8&9 组的身体活动量最低，与 Y1&2 组相比尤其如此（p<0.001）。
平均加速度、强度梯度和 MX 指标的百分位参考值可用于描述年轻人身体活动量和强度的年龄和性别特异性值。需要生成这些指标的全国代表性腕部加速度人群参考标准，以进一步促进与健康相关的身体活动研究和推广。
