Brewer Wayne, Swanson Brian T, Ortiz Alexis
School of Physical Therapy, Texas Woman's University, Institute of Health Sciences-Houston, Houston, Texas, USA.
School of Physical Therapy, University of New England, Portland, Maine, USA.
BMJ Open Sport Exerc Med. 2017 Sep 13;3(1):e000254. doi: 10.1136/bmjsem-2017-000254. eCollection 2017.
The main purpose of the study was to assess the validity between the Fitbit and ActiGraph GT3X+ accelerometer. The specific aims were to determine the: (1) concurrent validity between the various models of the Fitbit and the GTX3+ accelerometer as the criterion measure for: number of steps and active minutes averaged over a single-day and 7-day period; (2) validity of the two devices with the International Physical Activity Questionnaire (IPAQ) for the number of daily active minutes performed.
Fifty-three subjects wore a Fitbit and ActiGraph concurrently for 7 days. Data were analysed using correlation coefficients, t-tests to assess mean comparisons and Bland-Altman plots to determine agreement between the Fitbit and the ActiGraph.
The correlations between the Fitbit and ActiGraph for steps per day and per 7 days were r=0.862 and 0.820, respectively with significant mean differences between both devices. Bland-Altman analyses revealed agreement between the Fitbit and the ActiGraph for 7-day active minutes only. The correlations between the Fitbit and ActiGraph for active minutes per day and per 7 days were r=0.695 and r=0.658, respectively, with no significant mean differences between both devices. No significant correlations were found between the IPAQ and the other two devices.
The data produced by the Fitbit were consistent with the ActiGraph when the means of each device were compared over the 1-day and 7-day time periods. However, Bland-Altman analyses revealed that the Fitbit agreed with the ActiGraph when used to measure physical activity levels over a 7-day span only.
本研究的主要目的是评估Fitbit和ActiGraph GT3X+加速度计之间的效度。具体目标是确定：（1）Fitbit各型号与GTX3+加速度计之间的同时效度，作为以下指标的标准测量：单日和7天期间平均的步数和活跃分钟数；（2）两种设备与国际体力活动问卷（IPAQ）在每日活跃分钟数方面的效度。
53名受试者同时佩戴Fitbit和ActiGraph 7天。使用相关系数、t检验评估均值比较，并使用Bland-Altman图确定Fitbit和ActiGraph之间的一致性。
Fitbit和ActiGraph在每日步数和每7天步数上的相关性分别为r=0.862和0.820，两种设备之间存在显著的均值差异。Bland-Altman分析显示，仅在7天活跃分钟数方面，Fitbit和ActiGraph之间具有一致性。Fitbit和ActiGraph在每日活跃分钟数和每7天活跃分钟数上的相关性分别为r=0.695和r=0.658，两种设备之间无显著的均值差异。在IPAQ与其他两种设备之间未发现显著相关性。
当在1天和7天时间段内比较每个设备的均值时，Fitbit产生的数据与ActiGraph一致。然而，Bland-Altman分析显示，仅在用于测量7天期间的身体活动水平时，Fitbit与ActiGraph一致。
