Figure 5
From: Endurance training of respiratory muscles improves cycling performance in fit young cyclists
Changes in the partial pressure of end-tidal CO2 (PETCO2) as a function of the % endurance time during the constant work-rate exercise test, before and after training. There were no significant changes in either group, although the RMET group showed a trend towards a decrease after training (P = 0.18). Note that PETCO2 did decline markedly as a function of time during exercise in both groups, both before and after training, consistent with the upward drift in ventilation.