Table 2.
Criterion-related validity of the consumer-wearable activity trackers for estimating steps during controlled conditions (n = 56).
| Instrument | Mean (SD) | Equivalence test (90% CI) | LOA (95% CI) | MAE | MAPE | ICC (95% CI) |
|---|---|---|---|---|---|---|
| Slow pace walking | ||||||
| Video-based count | 335.3 (28.8) | -50.30, 50.30 | - | - | - | - |
| Samsung Pedometer | 334.8 (29.4) | -0.54, 1.65 | 0.6 (-9.0, 10.2) | 3.3 | 1.0 | 0.99 (0.98, 0.99) |
| Samsung Pacer | 334.7 (29.2) | -0.38, 1.59 | 0.6 (-8.0, 9.2) | 2.9 | 0.9 | 0.99 (0.98, 0.99) |
| Samsung GoogleFit | 334.7 (29.2) | -0.33, 1.58 | 0.6 (-7.8, 9.0) | 2.8 | 0.9 | 0.99 (0.98, 0.99) |
| Apple applications a | 332.6 (27.8) | 0.81, 4.59 | 2.7 (-14.0, 19.4) | 3.9 | 1.1 | 0.95 (0.92, 0.97) |
| Fitbit Ace 2 | 329.6 (30.4) | 2.81, 8.55 | 5.7 (-19.4, 30.8) | 8.2 | 2.5 | 0.89 (0.79, 0.94) |
| Garmin Vivofit Jr 2 | 334.1 (28.4) | 0.02, 2.44 | 1.2 (-9.4, 11.8) | 3.5 | 1.0 | 0.98 (0.97, 0.99) |
| Xiaomi Mi Band 5 | 334.0 (29.8) | 0.17, 2.47 | 1.3 (-8.9, 11.5) | 3.3 | 1.0 | 0.98 (0.97, 0.99) |
| Normal pace walking | ||||||
| Video-based count | 296.8 (23.2) | -44.52, 44.52 | - | - | - | - |
| Samsung Pedometer | 297.8 (23.9) | -2.14, 0.24 | -0.9 (-11.3, 9.5) | 3.8 | 1.3 | 0.97 (0.96, 0.99) |
| Samsung Pacer | 296.0 (22.8) | 0.29, 1.32 | 0.8 (-3.7, 5.3) | 1.7 | 0.6 | 0.99 (0.99, 1.00) |
| Samsung GoogleFit | 295.8 (23.1) | 0.07, 1.96 | 1.0 (-7.2, 9.2) | 2.2 | 0.7 | 0.98 (0.97, 0.99) |
| Apple applications a | 294.7 (22.5) | 0.86, 3.39 | 2.1 (-9.1, 13.3) | 2.7 | 0.9 | 0.97 (0.94, 0.98) |
| Fitbit Ace 2 | 286.8 (26.8) | 7.36, 12.67 | 10.0 (-13.3, 33.3) | 10.9 | 3.7 | 0.82 (0.42, 0.93) |
| Garmin Vivofit Jr 2 | 297.9 (24.8) | -2.69, 0.61 | -1.0 (-15.5, 13.5) | 4.9 | 1.6 | 0.95 (0.92, 0.97) |
| Xiaomi Mi Band 5 | 286.6 (31.3) | 6.40, 14.14 | 10.3 (-23.6, 44.2) | 11.7 | 4.0 | 0.75 (0.50, 0.87) |
| Brisk pace walking | ||||||
| Video-based count | 259.8 (17.8) | -38.97, 38.97 | - | - | - | - |
| Samsung Pedometer | 260.2 (17.8) | -1.56, 0.81 | -0.4 (-10.8, 10.0) | 3.7 | 1.5 | 0.96 (0.93, 0.97) |
| Samsung Pacer | 259.1 (17.7) | 0.07, 1.39 | 0.7 (-5.2, 6.6) | 2.1 | 0.8 | 0.99 (0.98, 0.99) |
| Samsung GoogleFit | 258.4 (18.5) | 0.07, 2.78 | 1.4 (-10.6, 13.4) | 2.8 | 1.1 | 0.94 (0.90, 0.97) |
| Apple applications a | 248.3 (22.2) | 7.18, 15.82 | 11.5 (-26.3, 49.3) | 12.0 | 4.5 | 0.47 (0.17, 0.67) |
| Fitbit Ace 2 | 236.8 (26.2) | 18.68, 27.28 | 23.0 (-14.6, 60.6) | 23.8 | 9.2 | 0.42 (0.00, 0.71) |
| Garmin Vivofit Jr 2 | 259.2 (18.0) | -1.30, 2.58 | 0.6 (-16.5, 17.7) | 5.9 | 2.3 | 0.88 (0.81, 0.93) |
| Xiaomi Mi Band 5 | 243.3 (28.8) | 10.95, 22.16 | 16.6 (-32.6, 65.8) | 17.9 | 6.9 | 0.37 (0.07, 0.60) |
| Running | ||||||
| Video-based count | 223.1 (32.0) | -33.47, 33.47 | - | - | - | - |
| Samsung Pedometer | 221.6 (32.0) | 0.64, 2.36 | 1.5 (-5.9, 8.9) | 3.0 | 1.4 | 0.99 (0.98, 1.00) |
| Samsung Pacer | 221.0 (31.3) | 0.43, 3.64 | 2.0 (-12.1, 16.1) | 3.6 | 1.5 | 0.97 (0.95, 0.98) |
| Samsung GoogleFit | 221.4 (31.0) | 0.00, 3.39 | 1.7 (-13.2, 16.6) | 3.9 | 1.7 | 0.97 (0.95, 0.98) |
| Apple applications a | 220.7 (30.9) | 0.73, 4.02 | 2.4 (-12.1, 16.9) | 3.3 | 1.4 | 0.97 (0.95, 0.98) |
| Fitbit Ace 2 | 209.8 (42.2) | 8.81, 17.69 | 13.3 (-25.7, 52.3) | 14.8 | 7.1 | 0.81 (0.54, 0.91) |
| Garmin Vivofit Jr 2 | 223.6 (32.3) | -1.51, 0.51 | -0.5 (-9.3, 8.3) | 3.3 | 1.5 | 0.99 (0.98, 0.99) |
| Xiaomi Mi Band 5 | 220.4 (32.1) | 1.33, 4.10 | 2.7 (-9.5, 14.9) | 4.3 | 2.0 | 0.98 (0.96, 0.99) |
SD = Standard deviation; LOA = Limits of Agreement; 90/95% CI = 90/95% Confident Interval; MAE = Mean Absolute Error; MAPE = Mean Absolute Percentage Error; ICC = Intraclass Correlation Coefficient.
a Apple applications is referred to the three applications activated in the iPhone smartphone (i.e., Pedometer, Pacer, and Apple Health) due to the fact that all of them reported exactly the same steps scores.