Table 3.
Differences between calibration methods in regression models of Actigraph counts and VO2 predicted by walking speed
| Outcome: Actigraph counts · min−1 | Outcome: VO2 (ml · kg−1 · min−1) | |||
|---|---|---|---|---|
| Parameter | Coef IPV |
(95 % CI) | Coef IPV |
(95 % CI) |
| Intercept | 1442*** 418*** |
(1319, 1565) | 8.96*** 2.13*** |
(8.37, 9.55) |
| Speed (centred at 3.5 km.h−1) |
1134*** 247*** |
(1061, 1207) | 1.56*** 0.61** |
(1.28, 1.84) |
| (Speed)2 | – – |
– | 0.30*** 0.22*** |
(0.21, 0.40) |
| C. method | 262*** 302*** |
(158, 366) | −2.25*** 1.10*** |
(−2.62, −1.89) |
| C. method × Speed | 198*** 145*** |
(147, 249) | −0.33 0.37* |
(−0.68, 0.02) |
| C. method × (Speed)2 | – – |
– | 0.08 0.12* |
(−0.03, 0.19) |
These regression models report on differences between calibration methods in Actigraph counts and VO2 at 3.5 km.h−1walking speed (see regression coefficients for C. method), and differences between calibration methods in associations of walking speed with Actigraph counts and VO2 (see regression coefficients for C. method by Speed and C. method by (Speed2)). Coef = regression coefficient; 95 % CI = 95 % confidence interval; BPV = between-participant variability in regression coefficients (expressed as standard deviations); – = not applicable; C. method = calibration method (treadmill is reference category); *p < .05; **p < .01; ***p < .001