Figure 9.

Simulated dynamic oxygen uptake responses during a 10-min moderate-intensity exercise bout (WR = 65W) for sedentary and chronically-loaded/unloaded individuals. The range of the x-axis is reduced in order to amplify the transient changes between loading states. The vertical bar located at time = 1 min divides the response into two phases. The initial muscle VO₂ responses at the onset of exercise (phase I) are largely functions of the blood flow response. In phase II, the responses are dependent on the intramuscular oxygen stores. The time constant of muscle VO₂ (τ_VO2) for loaded, sedentary and unloaded muscles was about 0.4, 0.5 and 0.56 min, respectively.