[Purpose] The aim of this study was to develop and assess the applicability of an experimental ankle-
foot orthosis during gait in patients with
hemiparesis. [Subjects and Methods] This was a noncontrolled cross-sectional study. Ten adult patients with
hemiparesis but who were capable of independent gait were included in the study. Gait assessment was performed using two platforms (EMG System do Brasil), an electromyograph (EMG System do Brasil), and a video camera. The experimental
orthosis consisted of a single piece that fit over the foot and 1/3 of the distal tibia and had a steel spring. [Results] There was greater activation of the rectus femoris and vastus lateralis muscles in the stance and mid-stance phases with the use of the experimental ankle-
foot orthosis in comparison with the use of a
polypropylene ankle-
foot orthosis and no
orthosis. Regarding spatial and temporal gait parameters, the individuals achieved an increase in stride length with the use of the experimental ankle-
foot orthosis in comparison with the use of a
polypropylene ankle-
foot orthosis. [Conclusion] The results of the present study demonstrate that individuals with
hemiparesis achieved an improvement in the stance and mid-stance phases of gait with the use of the experimental ankle-
foot orthosis.