Effects of Inspiratory Muscle Training on the Functional Gait Performance of Individuals After Stroke

The most commonly observed sequel after stroke is muscle weakness, which can also be identified in respiratory muscles, in the acute and chronic phases, and may compromise the lung function of these individuals. Studies have shown that lower Pimax values are found in non-community ambulators, and gait velocity has been reported as an important indicator of functionality after stroke, with higher gait velocity values associated with greater community participation and better quality of life.

This study will test the hypothesis that training of the inspiratory muscles is effective in improving strength and endurance of the inspiratory muscles and functionality, including speed of gait, functional gait perfomarnce, activities of daily living and quality of life with stroke subjects.

For this clinical trial, people after stroke will be randomly allocated into either experimental or control/sham groups. The experimental group will undertake training of the inspiratory muscles with the Power Breath Medical Classic device regulated at 50% of the subjects' maximal inspiratory pressure values, five times/week over six weeks, twice a day for 15 minutes, totaling 30 minutes/day. The control group will undertake the same protocol, but the participants will receive the devices with a minimal load, wich corresponds to 1cmH2O. Both groups will participate in the rehabilitation program for 6 weeks. At baseline and post intervention, after the cessation of the interventions, researchers blinded to group allocations will collect the following outcome measures: maximal respiratory pressures, respiratory muscle endurance, functional gait performance, activities of daily living and quality of life. After 12 weeks will collect again maximal inspiratory pressures and functional gait performance.

The most commonly observed sequel after stroke is muscle weakness, which can also be identified in respiratory muscles, in the acute and chronic phases, and may compromise the lung function of these individuals. Studies have shown that lower Pimax values are found in non-community ambulators, and gait velocity has been reported as an important indicator of functionality after stroke, with higher gait velocity values associated with greater community participation and better Quality of life.

Aim: This study will test the hypothesis that training of the inspiratory muscles is effective in improving strength and endurance of the inspiratory muscles and functional gait perfomarnce, activities of daily living and quality of life with stroke subjects.

Design: For this prospective, triple-blinded, randomized clinical trial, people after stroke will be randomly allocated into either experimental or control/sham groups. The experimental group will undertake training of the inspiratory muscles with the PowerBreath Medic Plus regulated at 50% of the subjects' maximal inspiratory pressure (MIP) values, five times/week over six weeks during 30 minutes/day. The control group will undertake the same protocol, but the participants will receive the threshold devices with minimal resistance valves. At baseline and post intervention after the cessation of the interventions, researchers blinded to group allocations will collect all outcome measures. After 12 weeks will collect again maximal inspiratory pressures and functional gait performance.

Study outcomes: Primary outcomes will be functional gait perfomarnce. Secondary outcomes will include inspiratory endurance, activities of daily living and quality of life.

Eligibility Criteria:
Inclusion Criteria:

* Adults with hemiparesis after stroke, of any etiology, ischemic or hemorrhagic, that carry out walking with or without assistance locomotion; Aged between 18 and 80 years of age; In the chronic period (between 6 months and 5 years); clinically stable (Measured through clinical and hemodynamic stability: vital signs within normal and released for physical activity by the physician), who present with inspiratory muscle weakness, defined as Pimáx less than -80cmH2O and score in the normal Mini Mental State Examination (MMSE) For schooling.

Exclusion Criteria:

* Smokers and ex-smokers for more than five years, presence of facial paralysis that prevents lip occlusion, associated neurological diseases, orthopedic alterations that include distortions of the chest cavity or pains that prevent the tests from being performed, respiratory dysfunctions, cardiac dysfunctions that Compromise hemodynamic stability.