Riel Henrik, Rathleff Camilla Rams, Kalstrup Pernille Møller, Madsen Niels Kragh, Pedersen Elena Selmar, Pape-Haugaard Louise Bilenberg, Villumsen Morten
Research Unit for General Practice, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
Department of Health Science and Technology, Aalborg University , Aalborg , Denmark.
PeerJ. 2016 Dec 22;4:e2799. doi: 10.7717/peerj.2799. eCollection 2016.
Walking is endorsed as health enhancing and is the most common type of physical activity among older adults. Accelerometers are superior to self-reports when measuring steps, however, if they are to be used by clinicians the validity is of great importance. The aim of this study was to investigate the criterion validity of Mother and ActiGraph wGT3X-BT in measuring steps by comparing the devices to a hand tally under controlled conditions in healthy participants.
Thirty healthy participants were fitted with a belt containing the sensor of Mother (Motion Cookie) and ActiGraph. Participants walked on a treadmill for two minutes at each of the following speeds; 3.2, 4.8, and 6.4 km/h. The treadmill walking was video recorded and actual steps were subsequently determined by using a hand tally. Wilcoxon's signed ranks test was used to determine whether Mother and ActiGraph measured an identical number of steps compared to the hand tally. Intraclass correlation coefficients were calculated to determine the relationship and Root Mean Square error was calculated to investigate the average error between the devices and the hand tally. Percent differences (PD) were calculated for between-instrument agreement (Mother vs. the hand tally and ActiGraph vs. the hand tally) and PDs below 3% were interpreted as acceptable and clinically irrelevant.
Mother and ActiGraph under-counted steps significantly compared to the hand tally at all walking speeds ( < 0.001). Mother had a median of total differences of 9.5 steps (IQR = 10) and ActiGraph 59 steps (IQR = 77). Mother had smaller PDs at all speeds especially at 3.2 km/h (2.5% compared to 26.7%). Mother showed excellent ICC values ≥0.88 (0.51-0.96) at all speeds whilst ActiGraph had poor and fair to good ICC values ranging from 0.03 (-0.09-0.21) at a speed of 3.2 km/h to 0.64 (0.16-0.84) at a speed of 6.4 km/h.
Mother provides valid measures of steps at walking speeds of 3.2, 4.8, and 6.4 km/h with clinically irrelevant deviations compared to a hand tally while ActiGraph only provides valid measurements at 6.4 km/h based on the 3% criterion. These results have significant potential for valid objective measurements of low walking speeds. However, further research should investigate the validity of Mother in patients at even slower walking speeds and in free-living conditions.
步行被认为有益健康，是老年人中最常见的身体活动类型。在测量步数时，加速度计优于自我报告，然而，如果临床医生要使用它们，其有效性至关重要。本研究的目的是通过在健康参与者的受控条件下将设备与手动计数进行比较，来调查Mother和ActiGraph wGT3X - BT在测量步数方面的标准效度。
30名健康参与者佩戴了一条装有Mother（Motion Cookie）和ActiGraph传感器的腰带。参与者在跑步机上以以下每种速度行走两分钟：3.2、4.8和6.4公里/小时。跑步机行走过程被视频记录下来，随后通过手动计数确定实际步数。使用Wilcoxon符号秩检验来确定Mother和ActiGraph测量的步数与手动计数相比是否相同。计算组内相关系数以确定关系，并计算均方根误差以研究设备与手动计数之间的平均误差。计算仪器间一致性的百分比差异（PD）（Mother与手动计数以及ActiGraph与手动计数之间），低于3%的PD被解释为可接受且与临床无关。
在所有行走速度下，与手动计数相比，Mother和ActiGraph显著少计步数（<0.001）。Mother的总差异中位数为9.5步（四分位距 = 10），ActiGraph为59步（四分位距 = 77）。Mother在所有速度下的PD较小，尤其是在3.2公里/小时时（2.5%，而ActiGraph为26.7%）。Mother在所有速度下均显示出优异的组内相关系数值≥0.88（0.51 - 0.96），而ActiGraph的组内相关系数值较差，在3.2公里/小时时为0.03（-0.09 - 0.21），在6.4公里/小时时为0.64（0.16 - 0.84），处于一般到良好之间。
Mother在3.2、4.8和6.4公里/小时的行走速度下能提供有效的步数测量，与手动计数相比偏差在临床方面无关紧要，而ActiGraph仅根据3%的标准在6.4公里/小时时能提供有效的测量。这些结果在低行走速度的有效客观测量方面具有巨大潜力。然而，进一步的研究应调查Mother在行走速度更慢的患者以及自由生活条件下的有效性。
