Use of an Ankle-Foot Orthosis Improves Aerobic Capacity in Subacute Hemiparetic Stroke Patients

Objective: To investigate aerobic capacity with and without an ankle-foot orthosis (AFO) in subacute hemiparetic stroke patients. Design: Prospective crossover intervention study. Setting: Rehabilitation clinic in secondary care. Patients: Patients diagnosed with first-ever cerebral stroke involving the cortical or subcortical area resulting in hemiparesis (n = 15, 8 men and 7 women; average age, 62.1 years). Methods: All subjects participated in 2 continuous, symptom-limited, low-velocity graded treadmill exercise stress tests under 2 different conditions, namely, with and without an AFO. The rest interval between tests was at least 48 hours. The order of exercise stress tests was randomized. Main Outcome Measurements: To assess cardiorespiratory responses, oxygen consumption, heart rate, systolic blood pressure, diastolic blood pressure, rate-pressure product, and respiratory exchange ratio were measured continuously throughout the test, and peak values were obtained. The rating of perceived exertion was recorded immediately after each test. The percentage of the age-predicted maximal heart rate and total exercise duration were also measured. Gait function was assessed by the Six-Minute Walk Test. Results: Using an AFO significantly increased peak oxygen consumption and Six-Minute Walk Test results. Peak values of each of heart rate, systolic blood pressure, diastolic blood pressure, rate-pressure product, and respiratory exchange ratio, rating of perceived exertion, percentage of age-predicted maximal heart rate, and total exercise duration were similar regardless of AFO use. Conclusions: Use of an AFO may improve aerobic capacity in subacute hemiparetic stroke patients, and may improve energy efficiency and gait endurance.