Fokkema Tryntsje, Kooiman Thea J M, Krijnen Wim P, VAN DER Schans Cees P, DE Groot Martijn
1Research Group Health Ageing, Allied Health Care and Nursing, Hanze University of Applied Sciences, Groningen, THE NETHERLANDS; 2Department of Rehabilitation Medicine, University Medical Centre, University of Groningen, Groningen, THE NETHERLANDS; and 3Quantified Self Institute, Hanze University of Applied Sciences, Groningen, THE NETHERLANDS.
Med Sci Sports Exerc. 2017 Apr;49(4):793-800. doi: 10.1249/MSS.0000000000001146.
To examine the test-retest reliability and validity of ten activity trackers for step counting at three different walking speeds.
Thirty-one healthy participants walked twice on a treadmill for 30 min while wearing 10 activity trackers (Polar Loop, Garmin Vivosmart, Fitbit Charge HR, Apple Watch Sport, Pebble Smartwatch, Samsung Gear S, Misfit Flash, Jawbone Up Move, Flyfit, and Moves). Participants walked three walking speeds for 10 min each; slow (3.2 km·h), average (4.8 km·h), and vigorous (6.4 km·h). To measure test-retest reliability, intraclass correlations (ICC) were determined between the first and second treadmill test. Validity was determined by comparing the trackers with the gold standard (hand counting), using mean differences, mean absolute percentage errors, and ICC. Statistical differences were calculated by paired-sample t tests, Wilcoxon signed-rank tests, and by constructing Bland-Altman plots.
Test-retest reliability varied with ICC ranging from -0.02 to 0.97. Validity varied between trackers and different walking speeds with mean differences between the gold standard and activity trackers ranging from 0.0 to 26.4%. Most trackers showed relatively low ICC and broad limits of agreement of the Bland-Altman plots at the different speeds. For the slow walking speed, the Garmin Vivosmart and Fitbit Charge HR showed the most accurate results. The Garmin Vivosmart and Apple Watch Sport demonstrated the best accuracy at an average walking speed. For vigorous walking, the Apple Watch Sport, Pebble Smartwatch, and Samsung Gear S exhibited the most accurate results.
Test-retest reliability and validity of activity trackers depends on walking speed. In general, consumer activity trackers perform better at an average and vigorous walking speed than at a slower walking speed.
研究10款活动追踪器在三种不同步行速度下进行步数计数的重测信度和效度。
31名健康参与者在跑步机上佩戴10款活动追踪器（Polar Loop、Garmin Vivosmart、Fitbit Charge HR、Apple Watch Sport、Pebble Smartwatch、三星Gear S、Misfit Flash、Jawbone Up Move、Flyfit和Moves），分两次步行30分钟。参与者以三种步行速度各走10分钟，分别为慢速（3.2千米/小时）、中速（4.8千米/小时）和快速（6.4千米/小时）。为测量重测信度，确定第一次和第二次跑步机测试之间的组内相关系数（ICC）。通过比较追踪器与金标准（人工计数），利用平均差异、平均绝对百分比误差和ICC来确定效度。采用配对样本t检验、Wilcoxon符号秩检验以及构建Bland-Altman图来计算统计差异。
重测信度的ICC范围为-0.02至0.97。不同追踪器和不同步行速度下的效度有所不同，金标准与活动追踪器之间的平均差异范围为0.0%至26.4%。大多数追踪器在不同速度下的ICC相对较低，Bland-Altman图的一致性界限较宽。对于慢速步行，Garmin Vivosmart和Fitbit Charge HR显示出最准确的结果。Garmin Vivosmart和Apple Watch Sport在中速步行时表现出最佳准确性。对于快速步行，Apple Watch Sport、Pebble Smartwatch和三星Gear S呈现出最准确的结果。
活动追踪器的重测信度和效度取决于步行速度。总体而言，消费级活动追踪器在中速和快速步行速度下的表现优于慢速步行速度。
