An articulated ankle foot orthosis with plantarflexion resistance decreased soleus and tibialis anterior muscle activity, and plantarflexion moment of the paretic lower limb of persons with stroke

Abstract

Ankle foot orthoses (AFOs) are important devices for assisting persons with stroke during walking, especially in mediating dorsiflexor weakness. The plantarflexion (PF) resistances of AFOs have been shown to augment dorsiflexor muscle function during the stance and swing phases of gait. However, it is not clear how this translates to the muscle activities of their paretic lower limbs. To further explore this question in stroke rehabilitation, 3D technology was used in designing and fabricating an individual-specific articulated AFO, which we assembled with a mechanical joint that enabled the application of PF resistances. We investigated the impact of regulating two PF resistances (PF1, PF2) on their paretic lower limb muscle activity. At PF2, there was significantly lower mean muscle activity for the Soleus in LR and the Tibialis anterior in the second rocker, pre-swing, and swing phases. The device only impacted the activity of the medial gastrocnemius muscle at the second rocker. The findings corroborated evidence regarding how AFOs with PF resistance impact the muscle activity of stroke survivors following a single session use; however, longitudinal studies are necessary to establish the impacts with long-term use, as most stroke survivors use AFOs long-term.