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. 2004 Jul 2;559(Pt 1):315–325. doi: 10.1113/jphysiol.2003.057729

Figure 5. Amplitude of the respiratory and locomotor responses as a function of the frequency of the sinusoidal changes in treadmill speed.

Figure 5

A, amplitude of the ventilatory and of the locomotor responses (mean ±s.e.m.) at each frequency of treadmill speed oscillation. Zero frequency corresponds to the steady-state response. Note the dissociation between the lack of change in the oscillations of the frequency of movement and the progressive reduction in V̇E amplitude when the frequency of treadmill speed oscillations increases. B, amplitude of the V̇O2 and V̇CO2 responses at each frequency of treadmill speed oscillation. Note that V̇O2 amplitude starts to decrease at a higher frequency than V̇CO2 (and V̇E), reflecting faster V̇O2 than V̇CO2 kinetics. C–E, relationship between the gain ratio (steady-state response–amplitude response ratio at each frequency) of ventilation and V̇CO2 (C) V̇O2 (D) and the locomotor response (E). Note that the change in amplitude ratio of the locomotor response has no relationship with the ventilatory response, which appears to follow the pulmonary gas exchange amplitude ratio.