The correlation of respiratory muscle strength and cough capacity in stroke patients.

The paper does not say how participants were assigned to groups or whether outcome assessors were blinded. Both groups continued general physical therapy, including neurological treatment, so the effect of respiratory muscle training alone cannot be separated. The study reports correlations between changes, not proof that increasing strength causes better cough. It did not measure swallowing, aspiration events or chest infections. Participants were selected to have no previous cardiovascular or respiratory problems, so results may not apply to stroke patients with those comorbidities.

Do not conclude that inspiratory and expiratory muscle training alone caused the cough improvement. Participants also received general physical therapy, including neurological treatment, and the paper does not report randomisation or blinding, so the contribution of the training cannot be separated.