INSPIRATORY MUSCLE CONDITIONING USING A THRESHOLD LOADING DEVICE

The effectiveness of a new conditioning technique for increasing the strength and endurance of the inspiratory muscles was demonstrated. The technique employs a threshold loading device which allows for maximization of exercise intensity with a minimum of exercise duration. After 10 wk, with .apprx. 25 min of exercise time per wk, 4 test subjects showed an average increase in maximum inspiratory pressure (PImax) of 50 (.+-. 9 SD) cm H2O (P < 0.02), whereas 4 control subjects undergoing submaximal inspiratory muscle exercise showed no significant change. The time the test subjects could endure 65% of their prestudy PImax increased from an average of 3.58 .+-. 1.65 SD min to over 10 min in all 4 subjects. No significant change was seen in control subjects. Further testing showed the test subjects could endure 100% of their prestudy PImax after conditioning for an average duration 5.15 .+-. 1.65 min. This technique should be useful for conditioning the inspiratory muscles in subjects with pulmonary disease.