Abstract
To overcome the problem of altered breathing strategy during resistive ventilatory muscle training (VMT), we used a single-orifice inspiratory resistance together with a target feedback device (TFD) in patients with chronic obstructive pulmonary disease (COPD). In a preliminary study (study A), we showed that the resistance plus TFD was effective in controlling breathing strategy. We subsequently used the resistor plus TFD in a 5-wk study (study B) of VMT in 17 COPD patients who were randomized into high-intensity (HI) and low-intensity (LI) training groups. Compared with the LI group , the HI group showed significant increases in static maximal inspiratory pressure (21.3 vs. 5.0 cmH2O), maximal sustained ventilatory capacity (MSVC, 3.2 vs. -0.1 l/min, sustained maximal mouth pressure (12.1 vs. 0.6 cmH2O), mean mouth pressure (6.9 vs. 3.9 cmH2O), peak inspiratory flow rate (12.3 vs. 4.0 l/min), and maximal sustained work rate (12.2 vs. 4.2 cmH2O .cntdot. l-1 .cntdot. min-1). We conclude that targeted VMT with control of breathing strategy improves both ventilatory muscle strength and endurance.