Energy expenditure in stroke subjects walking with a carbon composite ankle foot orthosis

Objective: To measure walking speed and energy cost in patients with prior stroke with and without a carbon composite ankle foot orthosis. Design: Within-group comparisons of 2 walking conditions. Participants: Convenience sample of 10 hemiparetic patients with a stroke at least 6 months earlier ( average age 52 years) habituated to a carbon composite ankle foot orthosis. Methods: Subjects walked on a treadmill at self-selected speed both with and without ankle foot orthosis for 5 minutes on each occasion. Energy expenditure was measured by breath-by-breath analysis and electrocardiography. Main outcome measures were walking speed, oxygen consumption, heart rate and energy cost per metre. Results: Walking speed: without ankle foot orthosis 0.27 ( SEM +/- 0.03) m/s, with 0.34 ( +/- 0.06) m/s, difference 20%. Oxygen consumption: without ankle foot orthosis 8.6 ( +/- 0.4) ml/kg/min, with 8.8 ( +/- 0.5) ml/kg/min. Energy cost: without ankle foot orthosis 0.58 ( +/- 0.07) ml/kg/m, with 0.51 ( +/- 0.06) ml/kg/m, difference 12%. Conclusion: Use of a carbon composite ankle foot orthosis in patients with stroke may increase speed and decrease energy cost during walking.