Respiratory muscles strength and endurance influence athletic performance. Besides conventional spirometry, sniff test, inspiratory and expiratory maximal pressures can directly assess respiratory muscle strength. Respiratory muscles can be train through a device offering inspiratory and expiratory resistance.Nineteen subjects aged 18 to 30 years and practicing leisure sport trained inspiratory muscles on Powerbreathe(®) for eight weeks. Resistance was set at 85% of maximal inspiratory pressure determined during a preliminary session. Evaluation was made trough voluntary and non-invasive methods on Macro 5000(®) (PI max, PE max and sniff test).An increase of 21.77% of the maximum inspiratory pressure, 17% of the maximum expiratory pressure and 18% of the sniff test are recorded after eight weeks of training.A specific training of inspiratory muscles (Powerbreathe(®) Sports performance) increases the power of these muscles (voluntary and non-invasive tests).