Table 2. Validity of the wearable activity trackers for estimating steps during structured free-living conditions (n = 56).
| Instrument |
Mean (SD) |
Equivalence test (90% CI) |
LOA (95% CI) |
MAE |
MAPE |
ICC (95% CI) |
| Slow pace walking |
| Video-based count |
306.6 (30.9) |
-45.99, 45.99 |
- |
- |
- |
- |
| Samsung Pedometer |
307.6 (32.4) |
-2.91, 1.01 |
-0.9 (-18.1, 16.3) |
6.2 |
2.0 |
0.96 (0.94, 0.98) |
| Samsung Pacer |
308.0 (29.8) |
-3.53, 0.78 |
-1.4 (-20.2, 17.4) |
5.8 |
1.9 |
0.95 (0.92, 0.97) |
| Samsung Google Fit |
307.1 (30.2) |
-2.48, 1.51 |
-0.5 (-17.9, 16.9) |
5.6 |
1.8 |
0.96 (0.93, 0.98) |
| Apple iPhone appsa |
307.1 (28.6) |
-4.13, 3.17 |
-0.5 (-32.4, 31.4) |
8.2 |
2.7 |
0.85 (0.76, 0.91) |
| Xiaomi Mi Band 5 |
303.7 (31.1) |
1.63, 4.15 |
2.9 (-7.9, 13.7) |
4.1 |
1.3 |
0.98 (0.95, 0.99) |
| Samsung Galaxy Watch Active 2 |
305.7 (31.0) |
-0.18, 1.96 |
0.9 (-8.5, 10.3) |
3.9 |
1.3 |
0.99 (0.98, 0.99) |
| Apple Watch Series 5 |
304.7 (30.9) |
1.15, 2.68 |
1.9 (-4.8, 8.6) |
3.1 |
1.0 |
0.99 (0.98, 1.00) |
| Normal pace walking |
| Video-based count |
261.4 (22.6) |
-39.21, 39.21 |
- |
- |
- |
- |
| Samsung Pedometer |
259.9 (23.9) |
-1.89, 4.96 |
1.5 (-28.5, 31.5) |
5.6 |
2.1 |
0.79 (0.66, 0.87) |
| Samsung Pacer |
262.0 (23.8) |
-2.33, 1.11 |
-0.6 (-15.7, 14.5) |
4.2 |
1.6 |
0.95 (0.91, 0.97) |
| Samsung Google Fit |
262.8 (22.8) |
-2.61, -2.14 |
-1.4 (-12.2, 9.4) |
3.5 |
1.4 |
0.97 (0.95, 0.98) |
| Apple iPhone appsa |
262.4 (23.9) |
-2.71, 0.71 |
-1.0 (-15.9, 13.9) |
4.5 |
1.7 |
0.95 (0.91, 0.97) |
| Xiaomi Mi Band 5 |
256.3 (25.2) |
3.36, 6.93 |
5.1 (-10.6, 20.8) |
6.0 |
2.4 |
0.92 (0.79, 0.97) |
| Samsung Galaxy Watch Active 2 |
258.1 (22.3) |
2.20, 4.37 |
3.3 (-6.1, 12.7) |
4.0 |
1.5 |
0.97 (0.89, 0.99) |
| Apple Watch Series 5 |
258.3 (22.7) |
1.96, 4.22 |
3.1 (-6.9, 13.1) |
3.9 |
1.5 |
0.97 (0.91, 0.99) |
| Brisk pace walking |
| Video-based count |
227.6 (18.2) |
-34.14, 34.14 |
- |
- |
- |
- |
| Samsung Pedometer |
230.5 (20.5) |
-4.95, -0.87 |
-2.9 (-20.7, 14.9) |
5.8 |
2.6 |
0.88 (0.80, 0.93) |
| Samsung Pacer |
229.3 (18.8) |
-3.27, -0.19 |
-1.7 (-15.2, 11.8) |
3.7 |
1.7 |
0.93 (0.88, 0.96) |
| Samsung Google Fit |
229.3 (18.9) |
-3.30, -0.20 |
-1.8 (-15.5, 11.9) |
3.9 |
1.7 |
0.93 (0.88, 0.96) |
| Apple iPhone appsa |
226.4 (18.1) |
0.41, 1.95 |
1.2 (-5.5, 7.9) |
2.5 |
1.1 |
0.98 (0.96, 0.99) |
| Xiaomi Mi Band 5 |
221.6 (23.2) |
2.95, 9.05 |
6.0 (-20.7, 32.7) |
7.3 |
3.2 |
0.76 (0.58, 0.86) |
| Samsung Galaxy Watch Active 2 |
222.1 (18.1) |
3.83, 7.21 |
5.5 (-9.4, 20.4) |
6.8 |
3.0 |
0.87 (0.62, 0.95) |
| Apple Watch Series 5 |
220.9 (21.1) |
4.27, 9.08 |
6.7 (-14.5, 27.9) |
8.1 |
3.6 |
0.81 (0.56, 0.90) |
| Running |
| Video-based count |
185.0 (24.0) |
-27.75, 27.75 |
- |
- |
- |
- |
| Samsung Pedometer |
187.7 (24.4) |
-4.86, -0.57 |
-2.7 (-21.5, 16.1) |
5.7 |
3.2 |
0.92 (0.86, 0.95) |
| Samsung Pacer |
188.3 (25.6) |
-4.96, -1.61 |
-3.3 (-18.0, 11.4) |
4.7 |
2.5 |
0.95 (0.90, 0.97) |
| Samsung Google Fit |
188.4 (25.7) |
-5.01, -1.72 |
-3.4 (-18.1, 11.3) |
4.9 |
2.7 |
0.95 (0.89, 0.97) |
| Apple iPhone appsa |
185.6 (23.5) |
-1.92, 0.77 |
-0.6 (-12.4, 11.2) |
3.3 |
1.8 |
0.97 (0.95, 0.98) |
| Xiaomi Mi Band 5 |
183.6 (24.6) |
0.23, 2.52 |
1.4 (-8.6, 11.4) |
3.6 |
2.0 |
0.98 (0.96, 0.99) |
| Samsung Galaxy Watch Active 2 |
183.6 (23.5) |
0.64, 2.29 |
1.5 (-5.8, 8.8) |
2.8 |
1.5 |
0.99 (0.97, 0.99) |
| Apple Watch Series 5 |
184.8 (23.8) |
-0.28, 0.71 |
0.2 (-4.1, 4.5) |
1.5 |
0.8 |
1.00 (0.99, 1.00) |
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 iPhone apps is referred to the three apps activated in the iPhone mobile (i.e., Pedometer, Pacer, and Apple Health).
