Figure 2.
Metabolic and cardiorespiratory responses in inclined running. The energy cost (A), the heart rate (B), the pulmonary ventilation (C), the respiratory frequency (D), and the tidal volume (E) of running at different speeds (▴ 8 km·h−1, υ 10 km·h−1, • 12 km·h−1, ■ 14 km·h−1, ■ By pooling all speeds) and slopes. For energy cost, fixed effects are calculated by pooling all speeds: slope effect: p < 0.001, speed fixed: p = 0.006, slope*speed interaction effect: p = 0.180. SD has been omitted for clarity. Panel (F) shows the ratio of inspiration time (Ti in black) and breathing duty cycle time as a function of treadmill slope. Error bars show SD; #p < 0.05 vs. 0% slope; $p < 0.05 vs. −20% slope.