Principal Investigators: Steven A. Kautz, PhD and Pam Duncan, PhD Project Category: Stroke Objective: The objective of this study is to determine whether a therapeutic exercise program designed to improve strength, balance, and endurance that targets the functional recovery of persons with post-stroke hemiparesis results in CNS recovery (improved motor coordination). Coordination will be assessed by variables calculated from pedal reaction forces and muscle activity patterns. Research Plan: Subjects will be 60-70 men and women aged 50 years or older, community-dwelling prior to stroke and discharged from inpatient rehabilitation. They will be free of post-stroke complications, have a diagnosis of first-time carotid distribution ischemic or hemorrhagic stroke of mild to moderate severity, and be ambulatory for 25 feet with supervision and/or an assistive device. Study participants will be randomized to either exercise intervention or control (usual care) group per the NIH study. Subjects are tested pre- and post-intervention or control period. The assessments will include all measures conducted for the NIH study (e.g. lower extremity motor function, gait velocity, balance), in addition to coordination measures from pedaling tasks on a stationary bicycle. Subjects pedal at three different cadences (self-selected, 40 rpm, and fastest comfortable) during pre- and post-treatment assessments. Bilateral pedal forces and EMG data will be collected (20 seconds). The variables of primary interest to evaluate the coordination of the paretic leg are: external mechanical work done and prolonged excitation of vastus medialis, phase-advanced excitation of rectus femoris and hamstrings. Work Accomplished: We found that there were no differences in the motor coordination measures after rehabilitation, even though there was an increased ability to pedal and walk faster. Thus, the changes appeared to be more compensatory in nature than restitutive with respect to motor performance. Further analysis of cross-sectional data will analyze the characteristics of individuals who most benefited from the rehabilitation. Expected Outcome: Determining that functional improvement after therapeutic exercise occurred without improvement in the coordination underlying the motor performance emphasizes the importance of endurance and strength training in rehabilitation. These and future results may contribute to developing a more rational basis for designing stroke rehabilitation programs for veterans which target individuals most likely to recover and which are based on physiological principles. Funding Source: VA RR&D Merit Review Funding Status: Funded |
