Resistive inspiratory muscle training in subjects with chronic cervical spinal cord injury

Objective: To determine whether pulmonary function, respiratory muscle strength, and dyspnea can be improved in individuals with chronic cervical spinal cord injury (SCI). Study Design: Ten subjects participated in an 8- week resistive inspiratory muscle training (IMT) program for 15 minutes twice daily. Spirometry, lung volumes, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), and dyspnea were measured at baseline, week 4, and week 8. Six months after the study, spirometry, MIP, and MEP were re-measured in a subgroup of the original participants. Results: We found that regular IMT in subjects with cervical SCI significantly improved forced vital capacity (means ± SE) (11% ± 2.82% increase), forced inspiratory vital capacity (21% ± 6.91%), vital capacity (8% ± 4.36%), total lung capacity (12% ± 3.23%), functional residual capacity (15% ± 5.96%), and MIP (24% ± 6.98%) (p < .05). Furthermore, although no statistical differences were observed for the dyspnea scale, the fact that subjects reported decreased levels (43% ± 21.30% reduction) of perceived difficulty breathing may be of greater importance. No significant differences from baseline values were found in the seven subjects whose spirometry and respiratory muscle strength were measured 6 months after the study. Conclusions: Our findings suggest that in individuals with cervical SCI regular resistive IMT may result in decreased restrictive ventilatory impairment and reported dyspnea and, thus, reduced incidence of chronic respiratory complaints, respiratory infection, and other pulmonary complications.