Fig. 4From: Interchangeability and optimization of heart rate methods for estimating oxygen uptake in ergometer cycling, level treadmill walking and runningModel comparisons for the estimated individual V̇O2 values. The figure is based on the individual V̇O2 values of all participants (n = 24), ranging between 25 and 85%HRR. Line of identity = solid line and the linear regression = dashed line. (a) Cycling, (b) walking, and (c) running. For regression equations and r2-coefficients, see Table 6Back to article page