How valid are wearable physical activity trackers for measuring steps?

Abstract

Wearable activity trackers have become popular for tracking individual's daily physical activity, but little information is available to substantiate the validity of these devices in step counts. Thirty-five healthy individuals completed three conditions of activity tracker measurement: walking/jogging on a treadmill, walking over-ground on an indoor track, and a 24-hour free-living condition. Participants wore 10 activity trackers at the same time for both treadmill and over-ground protocol. Of these 10 activity trackers three were randomly given for 24-hour free-living condition. Correlations of steps measured to steps observed were r = 0.84 and r = 0.67 on a treadmill and over-ground protocol, respectively. The mean MAPE (mean absolute percentage error) score for all devices and speeds on a treadmill was 8.2% against manually counted steps. The MAPE value was higher for over-ground walking (9.9%) and even higher for the 24-hour free-living period (18.48%) on step counts. Equivalence testing for step count measurement resulted in a significant level within ±5% for the Fitbit Zip, Withings Pulse, and Jawbone UP24 and within ±10% for the Basis B1 band, Garmin VivoFit, and SenseWear Armband Mini. The results show that the Fitbit Zip and Withings Pulse provided the most accurate measures of step count under all three different conditions (i.e. treadmill, over-ground, and 24-hour condition), and considerable variability in accuracy across monitors and also by speeds and conditions.

Group Outdoor Health Walks Using Activity Trackers: Measurement and Implementation Insight from a Mixed Methods Feasibility Study

“…First, accuracy can vary depending on walk setting and where the tracker is worn. Activity trackers are more accurate in limited settings such as treadmill exercise than in over-ground walking or free-living [74], and when worn on the hip or upper torso rather than the wrist [75]. Yet, the majority of people prefer to wear trackers on their wrists [76] and, in this study, activity was over-ground and free-living, thus introducing an element of error into the measurement.…”

Reliability of Trail Walking and Running Tasks Using the Stryd Power Meter

“…Commercially available wearable technology, and the biofeedback these devices provide, has been embraced by the heath and fitness field [1,2]. These devices have the ability to provide information regarding heart rate during exercise [3,4], overall step count [5,6], estimated energy expended [7,8], and even respiratory-associated measures [9,10]. There are many different wearable device types including wrist-worn monitors [3,4,6], monitors that attach to the hip [8,11,12], wearable garments [13,14], and earbuds [15,16].…”

Glycemic effect of post-meal walking compared to one prandial insulin injection in type 2 diabetic patients treated with basal insulin: A randomized controlled cross-over study

“…At the 1 st visit of run-in period, the participants received and were instructed how to use glucose meter (Freestyle Optium H, Abbot, USA), and accelerometer (Triaxial accelerometer, Fitbit zip, Fitbit, USA). This accelerometer device has been validated for its accuracy in several trials [13][14][15][16][17]. Diabetes education which included insulin injection, detection and correction of hypoglycemia, self-monitoring blood glucose (SMBG), and diet and food choices were provided to all participants.…”