Table 6.
Relative and absolute reliability of walking and sedentary time in seconds, assessed with ActivPAL3™, SENS motion®, and direct observations.
| Comparison | Mean (SD) of both assessments (sec) | Mean (SD) difference (sec) | p value for difference | ICC2.1 (95% CI) | SEM (SEM%) | MDC95 (MDC%) |
|---|---|---|---|---|---|---|
| Walking time | ||||||
| ActivPAL vs. observed | 146.6 (38.6) | -72.4 (68.5) | <0.001 | 0.059 (-0.104-0.272) | 37.4 (26) | 80.9 (55) |
| SENS vs. observed | 170.0 (37.6) | -25.5 (25.7) | <0.001 | 0.660 (0.079-0.863) | 21.9 (13) | 60.7 (36) |
| ActivPAL vs. SENS | 133.8 (40.3) | -46.9 (58.1) | <0.001 | 0.222 (-0.069-0.496) | 35.5 (27) | 98.4 (74) |
| Sedentary time | ||||||
| ActivPAL vs. observed | 192.3 (15.8) | -5.9 (11.0) | 0.003 | 0.740 (0.479-0.870) | 8.1 (4) | 22.5 (12) |
| SENS vs. observed | 190.8 (15.4) | -8.9 (9.6) | <0.001 | 0.718 (0.179-0.888) | 8.2 (4) | 22.7 (12) |
| ActivPAL vs. SENS | 187.9 (17.4) | 3.0 (12.2) | 0.159 | 0.776 (0.601-0.880) | 8.2 (4) | 22.7 (12) |
ICC: intraclass correlation coefficient; SEM: standard error of measurement (SD of mean [both assessments] × √1 − ICC); MDC: minimal detectable change (SEM × √2 × 1.96, SEM% = 100 × SEM/mean). SEM and MDC indicate measurement error (in sec) at group and individual levels, respectively. ActivPAL: ActivPAL3™ monitor; SENS: SENS motion®.