Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia.
Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.
Int J Behav Nutr Phys Act. 2021 Mar 17;18(1):39. doi: 10.1186/s12966-021-01105-y.
Physical activity (PA) decreases and sedentary time (SED) increases across childhood, with both behaviours tracking. However, no studies have examined how accumulation patterns of PA and SED (i.e., prolonged bouts, frequency of breaks in sedentary time) change and track over time. The aim of this study was to investigate longitudinal changes in and tracking of total volume and accumulation patterns of SED, light-intensity PA (LPA), moderate-intensity PA (MPA), vigorous-intensity PA (VPA) among boys and girls.
In 2008/09 (T1), children in HAPPY (3-5y; n = 758) in Melbourne, Australia wore ActiGraph GT1M accelerometers to objectively assess SED, LPA, MPA and VPA. This was repeated at age 6-8y (T2; n = 473) and 9-11y (T3; n = 478). Ten pattern variables were computed: bouts of ≥ 5-, ≥ 10-, ≥ 15- and ≥ 20-min for SED, ≥ 1- and ≥ 5-min for LPA, ≥ 1-min for MPA, ≥ 1- and ≥ 5-min for VPA, and breaks in SED (interruptions of > 25 counts 15 s). Longitudinal mixed models examined changes from T1-3, controlling for T1 age. Generalized estimating equations assessed tracking over the three time points, controlling for T1 age and time between measurements. Analyses were stratified by sex.
Total volume and bouts of SED and SED breaks increased, while total volume and bouts of LPA decreased for both sexes. There was a small decrease in total volume of MPA for girls, but time spent in ≥ 1-min bouts increased for both sexes. Total volume of VPA increased for both sexes, with time spent in ≥ 1-min bouts increasing for boys only. All volume and pattern variables tracked moderately for boys, except for all SED bouts ≥ 15-min, LPA bouts ≥ 5-min and MPA bouts ≥ 1-min (which tracked weakly). For girls, total SED and SED bouts ≥ 1-min tracked strongly, total volume of LPA, MPA and VPA, ≥ 5- and ≥ 10-min SED bouts, and ≥ 1-min LPA and MPA bouts tracked moderately, and SED breaks, all SED bouts ≥ 15 min, LPA bouts ≥ 5 min and all VPA bouts tracked weakly.
Patterns of SED and PA change from early to late childhood; with the exception of SED breaks and VPA, changes were detrimental. Total volumes and short bouts tended to track more strongly than longer bouts. Interventions to prevent declines in PA and increases in SED are important from early in life.
儿童期体力活动（PA）减少，久坐时间（SED）增加，两者都具有追踪性。然而，尚无研究探讨 PA 和 SED 的积累模式（即长时间的爆发、SED 中断的频率）如何随时间发生变化和追踪。本研究旨在调查男孩和女孩的 SED、低强度 PA（LPA）、中强度 PA（MPA）、高强度 PA（VPA）的总容量和积累模式的纵向变化和追踪。
2008/09 年（T1），澳大利亚墨尔本 HAPPY（3-5 岁；n=758）中的儿童佩戴 ActiGraph GT1M 加速度计客观评估 SED、LPA、MPA 和 VPA。在 6-8 岁（T2；n=473）和 9-11 岁（T3；n=478）时重复进行。计算了 10 个模式变量：SED 的≥5-、≥10-、≥15-和≥20 分钟爆发，LPA 的≥1-和≥5 分钟爆发，MPA 的≥1 分钟爆发，VPA 的≥1-和≥5 分钟爆发，SED 中断（中断 25 个计数 15 秒）。纵向混合模型控制 T1 年龄，检查 T1-3 期间的变化。广义估计方程评估了三个时间点的追踪情况，控制了 T1 年龄和测量之间的时间。分析按性别分层。
SED 和 SED 爆发的总量和爆发次数增加，而 LPA 和 SED 爆发的总量减少。女孩的 MPA 总量略有减少，但爆发次数增加。男孩和女孩的 VPA 总量增加，男孩的爆发次数增加。男孩的所有容量和模式变量的追踪效果中等，除了所有 SED 爆发时间≥15 分钟、LPA 爆发时间≥5 分钟和 MPA 爆发时间≥1 分钟（这些追踪效果较弱）。对于女孩，SED 和 SED 爆发时间≥1 分钟的总时间追踪效果很强，LPA、MPA 和 VPA 的总量、SED 爆发时间≥5-和≥10 分钟、LPA 和 MPA 爆发时间≥1 分钟的追踪效果中等，SED 中断、SED 爆发时间≥15 分钟、LPA 爆发时间≥5 分钟和所有 VPA 爆发时间追踪效果较弱。
SED 和 PA 的模式从儿童早期到晚期发生变化；除了 SED 中断和 VPA 外，所有变化都是有害的。总量和短爆发时间往往比长爆发时间更能紧密追踪。从生命早期开始，预防 PA 下降和 SED 增加的干预措施非常重要。
