Figure 3.

A: simulated ATP usage activity-exercise duration curves (corresponding to power-duration curves) for untrained muscle and trained muscle under the assumption that training causes an increase in oxidative phosphorylation (OXPHOS) activity (k_OX) from 0.8 to 1.1 of the standard value and a decrease of the peak P_i at which exercise is terminated (Pi_peak) from 25 mM to 22 mM (setB of simulations); B: simulated ATP usage activity minus 1/duration curves (corresponding to power minus 1/duration curves) for untrained muscle and trained muscle constituting transformed data from A.