Vandevenne A, Ducolone A, Weitzenblum E
Rev Pneumol Clin. 1984;40(5):285-92.
Ten subjects with chronic bronchitis with relatively severe bronchial obstruction and, in most cases, severe distension underwent strengthening of their respiratory muscles at home by an additional respiratory resistance load for 10 minutes 3 times a day for one month. All of these subjects obtained an increased endurance of the respiratory muscles without any concomitant increase in the inspiratory muscular force. For the group as a whole, the diameter of the orifice of maximal tolerated inspiratory resistance decreased from 3.15 to 2.40 mm (p less than 0.001) and the time of endurance increased from 7 to 15 minutes 34 seconds (p less than 0.001) while the maximal inspiratory muscular pressure remained virtually unchanged. This benefit was not associated with an increase in the VO2 max SL measured during maximal effort nor with any modification of the VO2, the VE or the heart rate during sub-maximal effort; the objective benefit therefore appears to be very limited.