inspiratory resistance muscle training, exercises that require inhalation against some type of resisting force. An example of such training is abdominal breathing practice with the Pflex or threshold inspiratory muscle trainer. The amount of resistance is gradually increased over several weeks of abdominal muscle training. Resistance may also be used against expansion of the rib cage by the intercostal musculature during inspiration. The resistance may be provided by a therapist pushing against the ribs or by applying a belt or swathe tightly about the costal margin.
