Can we train only expiratory or inspiratory muscles and not both?
Some patients with dysphagia or swallow problems may prefer in some instances to only train the expiratory muscles to really focus on these muscles.
So before they have a meal, they try to warm up and engage those expiratory muscles just in order to, if they aspirate, really cough out effectively. And it might make sense to do maybe one or two sets of five breaths in a really high expiratory setting.
But in general, we would recommend training both parts of the respiratory cycle.