Institute of Health & Society, Human Nutrition Research Centre, Newcastle University, M1.151 Leech Building Medical School, Framlington Place, Newcastle Upon Tyne NE2 4HH, United Kingdom.
Pediatrics. 2011 Jan;127(1):e24-30. doi: 10.1542/peds.2010-1935. Epub 2010 Dec 20.
Physical activity is thought to decline during childhood, but the extent of the decline is unknown. We made objective measures of 2-year changes in physical activity and sedentary behavior in English children who participated in the Gateshead Millennium Study to explore the nature, timing, and extent of changes in physical activity and sedentary behavior before adolescence.
We conducted a longitudinal study of 405 children (207 girls), aged 7 years, in 2006/2007 and again 24 months later. Physical activity and sedentary behavior were measured with the Actigraph GT1M accelerometer. Data were analyzed in 2010. Changes in total volume of physical activity (accelerometer counts per minute [cpm]), moderate-to-vigorous-intensity physical activity (MVPA), and sedentary behavior were quantified. Factors associated with changes in physical activity and sedentary behavior were tested by using linear regression. Tracking of physical activity and sedentary behavior over the 2-year period was assessed by rank-order correlation.
Mean daily volume of physical activity declined by 83 cpm (interquartile range [IQR]: -189 to 31) over 2 years; the percentage of daily time spent in MVPA was low at baseline and declined by 0.3% (IQR: -1.4 to 0.9). The percentage of daily time in sedentary behavior was high at baseline and increased from 78.0% to 81.1% of the day (change 3.1% [IQR: -0.3 to 6.0]). The decline in MVPA and increase in sedentary behavior were significantly greater in girls and in those with higher BMI z scores at baseline. Physical activity and sedentary behavior showed moderate tracking over the 2-year period.
We report here new evidence of low and declining levels of physical activity and MVPA and increasing sedentary behavior before adolescence.
体力活动被认为会在儿童期下降，但下降的程度尚不清楚。我们对参加盖茨黑德千年研究的英国儿童进行了为期 2 年的体力活动和久坐行为的客观测量，以探讨青春期前体力活动和久坐行为变化的性质、时间和程度。
我们对 405 名（207 名女孩）年龄为 7 岁的儿童进行了一项纵向研究，这些儿童于 2006/2007 年和 24 个月后再次参加研究。使用 Actigraph GT1M 加速度计测量体力活动和久坐行为。2010 年进行数据分析。量化了总体力活动量（每分钟加速度计计数值[cpm]）、中高强度体力活动（MVPA）和久坐行为的变化。通过线性回归测试与体力活动和久坐行为变化相关的因素。通过等级相关评估体力活动和久坐行为在 2 年期间的跟踪情况。
平均每日体力活动量下降了 83 cpm（四分位距[IQR]：-189 至 31），2 年内每日 MVPA 时间百分比较低，下降了 0.3%（IQR：-1.4 至 0.9）。每日久坐行为时间百分比较高，从基线的 78.0%增加到 81.1%（变化 3.1%[IQR：-0.3 至 6.0]）。在女孩和基线 BMI z 分数较高的人群中，MVPA 的下降和久坐行为的增加更为显著。体力活动和久坐行为在 2 年期间具有中等的跟踪性。
我们在此报告了新的证据，表明青春期前体力活动和 MVPA 水平较低且呈下降趋势，久坐行为增加。
