Abbott R A, Davies P S W
School of Human Movement Studies, University of Queensland, St Lucia, Australia.
Eur J Clin Nutr. 2004 Feb;58(2):285-91. doi: 10.1038/sj.ejcn.1601780.
Concerns of a decrease in physical activity levels (PALs) of children and a concurrent increase in childhood obesity exist worldwide. The exact relation between these two parameters however has as yet to be fully defined in children.
This study examined the relation in 47 children, aged 5-10.5 y (mean age 8.4+/-0.9 y) between habitual physical activity, minutes spent in moderate, vigorous and hard intensity activity and body composition parameters.
Total energy expenditure (TEE) was calculated using the doubly labelled water technique and basal metabolic rate (BMR) was predicted from Schofield's equations. PAL was determined by PAL=TEE/BMR. Time spent in moderate, vigorous and hard intensity activity was determined by accelerometry, using the Tritrac-R3D. Body fatness and body mass index (BMI) were used as the two measures of body composition.
Body fat and BMI were significantly inversely correlated with PAL (r=-0.43, P=0.002 and r=-0.45, P=0.001). Times spent in vigorous activity and hard activity were significantly correlated to percentage body fat (r=-0.44, P=0.004 and r=-0.39, P=0.014), but not BMI. Children who were in the top tertiles for both vigorous activity and hard activity had significantly lower body fat percentages than those in the middle and lowest tertiles. Moderate intensity activity was not correlated with measures of body composition.
As well as showing a significant relation between PAL and body composition, these data intimate that there may be a threshold of intensity of physical activity that is influential on body fatness. In light of world trends showing increasing childhood obesity, this study supports the need to further investigate the importance of physical activity for children.
全球都存在儿童身体活动水平（PALs）下降以及儿童肥胖率同时上升的问题。然而，这两个参数之间的确切关系在儿童中尚未完全明确。
本研究调查了47名5至10.5岁（平均年龄8.4±0.9岁）儿童的习惯性身体活动、中度、剧烈和高强度活动所花费的时间与身体成分参数之间的关系。
使用双标水技术计算总能量消耗（TEE），并根据斯科菲尔德方程预测基础代谢率（BMR）。PAL通过PAL = TEE/BMR确定。使用Tritrac - R3D加速度计确定中度、剧烈和高强度活动所花费的时间。身体脂肪和体重指数（BMI）被用作身体成分的两种测量指标。
身体脂肪和BMI与PAL显著负相关（r = -0.43，P = 0.002；r = -0.45，P = 0.001）。剧烈活动和高强度活动所花费的时间与体脂百分比显著相关（r = -0.44，P = 则0.004；r = -0.39，P = 0.014），但与BMI无关。在剧烈活动和高强度活动中处于最高三分位数的儿童的体脂百分比明显低于处于中间和最低三分位数的儿童。中度强度活动与身体成分测量指标无关。
这些数据不仅显示了PAL与身体成分之间的显著关系，还表明可能存在一个对身体脂肪有影响的身体活动强度阈值。鉴于全球儿童肥胖率呈上升趋势，本研究支持进一步调查身体活动对儿童的重要性的必要性。
