Correlation between respiratory muscle strength and arm muscle strength of the unaffected side in patients with sub-acute stroke

[Purpose] To prospectively examine the relationship between respiratory muscle strength and proximal and distal arm muscle strength on the unaffected side in patients with sub-acute stroke during rehabilitation. [Participants and Methods] Twenty patients with hemiplegic stroke admitted to a post-acute rehabilitation unit were included. Maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), shoulder flexion strength (index of the proximal portion), and handgrip strength (index of the distal portion) were measured bilaterally on admission and at one month and two months post-admission. [Results] MIP and MEP were significantly increased two months post-admission, particularly MEP. Bilateral arm muscle strength significantly increased in the proximal and distal portions during intensive rehabilitation. On the unaffected side, the strength of the proximal portion was lower than that of the distal portion. Positive correlations were observed between MIP and MEP, and arm muscle strength on the unaffected side, at each time point. Notably, the correlation coefficient tended to be higher with MEP than with MIP. [Conclusion] MIP and MEP correlated with arm muscle strength on the unaffected side during sub-acute rehabilitation.