EFFECT OF INSPIRATORY MUSCLE TRAINING WITH AN INTERMEDIATE LOAD ON INSPIRATORY POWER OUTPUT IN COPD

There is very little information about the effect of inspiratory muscl e training on inspiratory how (V'I) and thus an power output (PO) in p atients with chronic obstructive pulmonary disease (COPD). In this stu dy me aimed to evaluate the changes induced by training on the determi nants of pg), Thirty one patients with severe COPD were randomly divid ed into: Group I, trained with 30% maximal inspiratory pressure (PI, m ax); Group 2, with 10% PI,max; and Group 3 also trained with 30% PI,ma x, but the breathing pattern was evaluated while performing the traini ng manoeuvres along inspiratory muscle training (TMT). All groups used a threshold device for 10 weeks. The PO for each of the loads during an incremental threshold test was evaluated prior to and after trainin g, Maximal PO (POmax) increased in all groups, but the increment was h igher in groups trained with 30% PI,max (p<0.005), mainly due to an in crease in V'I, Group 3 showed a progressive increase in V'I (p<0.005) during the training manoeuvres in spite of an increase in load along I MT. In addition, the load after IMT was overcome with a shorter inspir atory time (tI) (p<0.02), a smaller tI/total duration of the respirato ry cycle (ttot), (p<0.001) with no change in tidal volume or ttot, The increment in POmax in this group correlated with the V'I generated wh ile training (r=0.85; p<0.0001). We conclude that in patients with chr onic obstructive pulmonary disease, the use of an intermediate thresho ld load for training improves es power output mainly by increasing ins piratory how, an effect consistent with an increase in shortening velo city of inspiratory muscles.