Movement Behaviours, Nutrition, Health & Wellbeing Research Group, Department Sport & Physical Activity, Edge Hill University, St Helens Road, Ormskirk L39 4QP, UK.
Research Institute of Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK.
Int J Environ Res Public Health. 2022 Jul 19;19(14):8778. doi: 10.3390/ijerph19148778.
We examined the compositional associations between the intensity spectrum derived from incremental acceleration intensity bands and the body mass index (BMI) z-score in youth, and investigated the estimated differences in BMI z-score following time reallocations between intensity bands. School-aged youth from 63 schools wore wrist accelerometers, and data of 1453 participants (57.5% girls) were analysed. Nine acceleration intensity bands (range: 0−50 mg to ≥700 mg) were used to generate time-use compositions. Multivariate regression assessed the associations between intensity band compositions and BMI z-scores. Compositional isotemporal substitution estimated the differences in BMI z-score following time reallocations between intensity bands. The ≥700 mg intensity bandwas strongly and inversely associated with BMI z-score (p < 0.001). The estimated differences in BMI z-score when 5 min were reallocated to and from the ≥700 mg band and reallocated equally among the remaining bands were −0.28 and 0.44, respectively (boys), and −0.39 and 1.06, respectively (girls). The time in the ≥700 mg intensity band was significantly associated with BMI z-score, irrespective of sex. When even modest durations of time in this band were reallocated, the asymmetrical estimated differences in BMI z-score were clinically meaningful. The findings highlight the utility of the full physical activity intensity spectrum over a priori-determined absolute intensity cut-point approaches.
我们研究了从增量加速度强度带得出的强度谱与青少年体重指数（BMI）z 分数之间的组成关联，并调查了在强度带之间重新分配时间后 BMI z 分数的估计差异。来自 63 所学校的学龄青少年佩戴腕部加速度计，对 1453 名参与者（57.5%为女孩）的数据进行了分析。使用了九个加速度强度带（范围：0-50mg 至≥700mg）来生成时间利用组成。多元回归评估了强度带组成与 BMI z 分数之间的关联。组成等时替代估计了在强度带之间重新分配时间后 BMI z 分数的差异。≥700mg 强度带与 BMI z 分数呈强烈的负相关（p<0.001）。当 5 分钟重新分配到≥700mg 带和从该带重新分配以及在其余带之间平均分配时，BMI z 分数的估计差异分别为-0.28 和 0.44（男孩），-0.39 和 1.06（女孩）。≥700mg 强度带中的时间与 BMI z 分数显著相关，与性别无关。当该带中的时间甚至适度延长时，BMI z 分数的估计差异呈不对称性，且具有临床意义。这些发现突出了使用完整的体力活动强度谱而不是事先确定的绝对强度切点方法的实用性。
