Table 4.
Community based test-retest reliability for AX3 wearable system micro and micro gait measurement
| Variables | Median (IQR) | Agreement | ||||
|---|---|---|---|---|---|---|
| Week 1 | Week 2 | Median difference (%) | ICC | LoA % (95% LoA) | r | |
| Macro characteristics | ||||||
| Total daily step count | 7825 (6428) | 7191 (5920) | −634 (−9%) | 0.917** | 0.9 (3138, −4470) | 0.892** |
| Mean walking bout length (s) | 17.12 (2.56) | 16.3 (6.2) | −0.82 (−5%) | 0.919** | 0.4 (3.036, −3.565) | 0.894** |
| Total number of daily walking bouts | 535 (288) | 462 (237) | −73 (16) | 0.867** | 2 (226,-272) | 0.823** |
| Alpha (unit less) | 1.614 (0.535) | 1.615 (0.068) | 0.001 (0.06) | 0.948** | 0.1 (0.05, −0.046) | 0.853** |
| Variability (s) | 0.840 (0.057) | 0.842 (0.105) | 0.002 (0.2%) | 0.887** | 0.2 (0.08, −0.094) | 0.801** |
| Micro characteristics | ||||||
| Mean | ||||||
| Step velocity (m/s) | 1.05 (0.165) | 1.07 (0.152) | 0.02 (1.9) | 0.958** | 0.17 (0.087, −0.093) | 0.914** |
| Step length (m) | 0.610 (0.085) | 0.610 (0.085) | 0 (0) | 0.969** | 1.2 (0.034, −0.038) | 0.940** |
| Step time (s) | 0.613 (0.353) | 0.622 (0.38) | 0.009 (1) | 0.951** | 0.07(0.022, −0.018) | 0.889** |
| Swing time (s) | 0.474 (0.032) | 0.475 (0.030) | 0.001 (0.2) | 0.962** | 0.07 (0.02,-0.013) | 0.925** |
| Stance time (s) | 0.764 (0.040) | 0.766 (0.047) | 0.002 (0.2) | 0.942** | 0.1 (0.026, −0.026 | 0.863** |
| Variability | ||||||
| Step velocity (m/s) | 0.385 (0.048) | 0.383 (0.042) | −0.002 (−0.5) | 0.905** | 0.2 (0.04, −0.0345) | 0.914** |
| Step length (m) | 0.162 (0.021) | 0.159 (0.017) | 0.003 (−2%) | 0.944** | 0.12 (0.034, −0.0384) | 0.940** |
| Step time (s) | 0.183 (0.041) | 0.181 (0.044) | −0.002 (−1) | 0.982** | 0.17 (0.018, −0.0149) | 0.889** |
| Swing time (s) | 0.152 (0.040) | 0.150 (0.039) | −0.002 (−1.3) | 0.983** | 0.15 (0.0119,-0.0113) | 0.925** |
| Stance time (s) | 0.193 (0.042) | 0.193 (0.044) | 0 (0) | 0.982** | 0.2 (0.0189, −0.0169) | 0.863** |
| Asymmetry | ||||||
| Step length (m) | 0.082 (0.019) | 0.090 (0.021) | 0.008 (9%) | 0.668** | 0.7 (0.0337, −0.0245) | 0.599** |
| Step time (s) | 0.123 (0.037) | 0.120 (0.044) | −0.003 (−2.5) | 0.875** | 0.6 (0.0357, −0.0344) | 0.788** |
| Swing time (s) | 0.109 (0.040) | 0.101 (0.049) | −0.008 (−8%) | 0.925** | 0.5 (0.026, −0.0261) | 0.850** |
| Stance time (s) | 0.123 (0.04) | 0.109 (0.030) | −0.01 (−13%) | 0.878** | 0.6 (0.0357, −0.0398) | 0.742** |
IQR Interquartile range, s seconds, ICC Intraclass correlation coefficient, LoA% limits of agreement as a percentage of the mean of the two systems, r Spearman’s rank correlation coefficient
**p ≤ 0.01 *p ≤ 0.05