Target-flow inspiratory muscle training at home and during pulmonary rehabilitation in COPD patients with a ventilatory limitation during exercise

The effects of a 10-week inspiratory muscle training (IMT) program at home were compared to IMT during a 10-week pulmonary rehabilitation program (PR) in 40 COPD patients with a ventilatory limitation of the exercise capacity. IMT was performed with a target-flow resistive device; the generated mouth pressure as well as the duty cycle were imposed. The mean age of the patients was 59, the mean FEV₁ was 48% of predicted. In the training period the inspiratory muscle strength improved in both groups to the same degree. EMG fatigability of the diaphragm improved in the PR + IMT group, but not in the IMT group. In theIMT group, the 12-min walking distance increased after the training period, but maximal workload (W_max), \(\dot VO_{2,max} \) , and ADL scores did not change. In thePR + IMT group, however, W_max, \(\dot VO_{2,max} \) , walking distance, and ADL scores improved significantly after the training period. Walking distance and ADL scores showed a significantly greater improvement in the PR + IMT group than in the IMT group. It is concluded that both isolated IMT and PR + IMT in COPD patients with a ventilatory limitation have a beneficial effect on inspiratory muscle strength, but PR + IMT improves the physical exercise capacity significantly more than IMT alone.