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Table 1 Regression models of prediction error for walking speed and VO2 by calibration method

From: Validity of treadmill- and track-based individual calibration methods for estimating free-living walking speed and VO2 using the Actigraph accelerometer

  Prediction error for speed of walking (km · h−1) Prediction error for VO2 (ml · kg−1 · min−1)
Regression parameter Treadmill method Track method Treadmill method Track method
  Coefficient
(95 % CI )
BPV
Coefficient
(95 % CI)
BPV
Coefficient
(95 % CI)
BPV
Coefficient
(95 % CI)
BPV
Intercept 0.71***
(0.56, 0.87)
0.54***
0.02
(−0.05, 0.08)
0.19***
4.99***
(3.96, 6.00)
3.26***
0.33
(−0.06, 0.73)
1.10***
Speed 0.15***
(0.06, 0.24)
0.26***
−0.04
(−0.09, 0.01)
0.08*
1.16***
(0.58, 1.75)
1.57***
−0.29**
(−0.49, −0.08)
(Speed)2 −0.06*
(−0.11, −0.01)
0.13*
−0.04
(−0.09, 0.01)
0.10**


−0.20*
(−0.38, −0.02)
  1. These regression models report on average prediction error by calibration method (see intercept values) and if this error depends on walking speed (see regression coefficients for speed and speed2). Coefficient = regression coefficient; 95 % CI = 95 % confidence interval; BPV = Between-participant variability in regression coefficients (expressed as standard deviations); – = not applicable (not significant regression term or between-participant variability based on a comparison of fixed and random slope models); *p < .05; **p < .01; ***p < .001. Speed (km · h−1) was centered at 5 · 7 km.h−1