Combined influence of epoch length, cut-point and bout duration on accelerometry-derived physical activity.
Combined influence of epoch length, cut-point and bout duration on accelerometry-derived physical activity.
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DOI：
10.1186/1479-5868-11-34
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发表时间：
2014-03-10
期刊：
影响因子：
--
通讯作者：
Brage S
中科院分区：
文献类型：
--
作者：
Orme M;Wijndaele K;Sharp SJ;Westgate K;Ekelund U;Brage S
由于数据处理程序的不同，很难比较不同研究之间由加速计得出的中等到剧烈体力活动(MVPA)的估计。我们的目的是评估加速计处理方式对成年人在MVPA中花费的总时间和累计时间的影响。来自前瞻性试验的267名参与者提供了1236天的有效体力活动(PA)数据，使用带有Actigraph GT1M加速计的5-S纪元收集。我们综合了从5-S到60-S历元长度(EL)的数据，并将两级混合效应回归模型应用于MVPA时间，定义为1500到2500次/分钟(CPM)、界点(CP)和回合持续时间(BD)从1到15分钟。总MVPA时间在较长EL和较高CP的情况下较短(在5-S和60-S时期，1500和2500CPM分别为47vs26min/d和26vs5min/d)，可近似为MVPA = exp[2.197 + 0.279*log(CP) + 6.120*log(EL)-0.869*log(CP)*log(EL)]，磨损时间为800min/d。相反，EL与在MVPA中花费的时间呈正相关；近似方程为MVPA = EXP[54.679-6.268*LOG(CP) + 6.387*LOG(EL)-10.000*LOG(BD)-0.162*LOG(EL)*LOG(BD)-MVPABD和CP与MVPA呈负相关，较高的值减弱了EL的影响。EL、CP和BD相互作用，影响加速度计确定的MVPA的估计。一般来说，较高的CP和较长的BD会导致较低的MVPA，但EL的关联方向取决于BD。报告这些关键参数在其经常使用的范围内的比例系数将有助于比较人口水平对MVPA的加速度法估计。
It is difficult to compare accelerometer-derived estimates of moderate-to-vigorous physical activity (MVPA) between studies due to differences in data processing procedures. We aimed to evaluate the effects of accelerometer processing options on total and bout-accumulated time spent in MVPA in adults. 267 participants from the ProActive Trial provided 1236 days of valid physical activity (PA) data, collected using a 5-s epoch with ActiGraph GT1M accelerometers. We integrated data over 5-s to 60-s epoch lengths (EL) and applied two-level mixed effects regression models to MVPA time, defined using 1500 to 2500 counts/minute (cpm) cut-points (CP) and bout durations (BD) from 1 to 15 min. Total MVPA time was lower on longer EL and higher CP (47 vs 26 min/day and 26 vs 5 min/day on 1500 vs 2500 cpm on 5-s and 60-s epoch, respectively); this could be approximated as MVPA = exp[2.197 + 0.279*log(CP) + 6.120*log(EL) - 0.869*log(CP)*log(EL)] with an 800 min/day wear-time. In contrast, EL was positively associated with time spent in bout-accumulated MVPA; the approximating equation being MVPA = exp[54.679 - 6.268*log(CP) + 6.387*log(EL) - 10.000*log(BD) - 0.162*log(EL)*log(BD) - 0.626*log(CP)*log(EL) + 1.033*log(CP)*log(BD)]. BD and CP were inversely associated with MVPA, with higher values attenuating the influence of EL. EL, CP and BD interact to influence estimates of accelerometer-determined MVPA. In general, higher CP and longer BD result in lower MVPA but the direction of association for EL depends on BD. Reporting scaling coefficients for these key parameters across their frequently used ranges would facilitate comparisons of population-level accelerometry estimates of MVPA.
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影响因子：
4.5
作者：
Williams K;Prevost AT;Griffin S;Hardeman W;Hollingworth W;Spiegelhalter D;Sutton S;Ekelund U;Wareham N;Kinmonth AL
通讯作者：
Kinmonth AL
DOI：
10.1097/00005768-199805000-00021
发表时间：
1998-05-01
期刊：
MEDICINE AND SCIENCE IN SPORTS AND EXERCISE
影响因子：
--
作者：
Freedson, PS;Melanson, E;Sirard, J
通讯作者：
Sirard, J
影响因子：
6.9
作者：
Catenacci, Victoria A.;Grunwald, Gary K.;Wyatt, Holly R.
通讯作者：
Wyatt, Holly R.
影响因子：
3.3
作者：
Staudenmayer, John;Pober, David;Freedson, Patty
通讯作者：
Freedson, Patty
影响因子：
1.8
作者：
Nilsson, A;Ekelund, U;Sjöström, M
通讯作者：
Sjöström, M