One study concluded: Inspiratory Muscle Training may potentially strengthen the inspiratory muscles and slow the decline in respiratory function in patients with ALS/MND1.
And another study concluded: With Inspiratory Muscle Training, respiratory muscle function can be improved in the long term of up to 2 years2.
1 INSPIRATIonAL–INSPIRAtory muscle training in amyotrophic lateral sclerosis
2 2 Years’ experience with inspiratory muscle training in patients with neuromuscular disorders