Hi All,
There was a trial on breathing a few years ago and it showed improvement in MIP with breath training. I have one of them and actually have the one Doglady describes but that wasn't the one used for the study. I discovered using my cough assist machine in reverse helped expand my lungs. I bought measuring equipment to test MEP, MIP, and SNIP and another device that will test FVC, SVC, MVV and a bunch of other numbers. Now I can track my own breathing at the same time each week (best on empty stomach first thing in the morning for me) without operator error or differences in fatigue. If you go to ALSTDI we talk about the specific equipment, results of the study, and how it is working for us. I believe the thread was started in late 2016 or early 2017.
Others use(d) breath stacking to achieve similar results total lung capacity.