Gait and Muscle Activity Changes in Patients in the Recovery Phase of Stroke with Continuous Use of Ankle–Foot Orthosis with Plantarflexion Resistance

OBJECTIVE: Previous studies have suggested that the use of an ankle–foot orthosis may cause disuse atrophy of the tibialis anterior muscle. The objective of this study was to explore gait and muscle activity changes in patients in the recovery phase of stroke with 2-month use of an ankle–foot orthosis that provided plantarflexion resistance. METHODS: The participants were 19 patients in the recovery phase of stroke who were prescribed an ankle–foot orthosis that provided plantarflexion resistance. We measured ankle and shank tilt angles as well as electromyography activity of the tibialis anterior and the soleus during 10-m walk tests. Measurements were taken on three occasions. The first was 2 weeks after delivery of the orthosis, 1 and 2 months after the initial measurement, and the third 2 months later. Changes in gait parameters were analyzed between the first and second measurements and between the second and third measurements. RESULTS: Between the second and third measurements, significant increases were observed in plantarflexion and shank forward tilt angles and the activity ratio of the tibialis anterior during loading response compared with other phases. CONCLUSIONS: Plantarflexion movement induced by an ankle–foot orthosis with plantarflexion resistance could increase the activity ratio of the tibialis anterior during loading response.