Soleus Loading Response During Walking

Able-bodied participants are enrolled. The robotic ankle device applies ankle joint rotations using a computer-controlled closed-loop algorithm to evoke the soleus loading response during the mid-late stance phase during treadmill walking at a self-selected comfortable fast speed. The algorithm applies ankle perturbations, which are shifts from the natural ankle kinematics to target the soleus loading response in mid-late stance phase every other 4-6 gait cycles. The perturbation magnitude, speed, and timing are controlled by the device to adjust the participant's soleus response. Four-to-five walking bouts are conducted interleaving perturbed and unperturbed walking steps (until collecting data of about 30 perturbed and unperturbed steps per walking bout) leaving at least one unperturbed step before a perturbed step. Changes in the soleus EMG will be compared between perturbed and unperturbed walking steps.

Participants with spastic hemiparesis due to a stroke are enrolled. The robotic ankle device applies ankle joint rotations using a computer-controlled closed-loop algorithm to evoke the soleus loading response during the mid-late stance phase during treadmill walking at a self-selected comfortable fast speed. The algorithm applies ankle perturbations, which are shifts from the natural ankle kinematics to target the soleus loading response in mid-late stance phase every other 4-6 gait cycles. The perturbation magnitude, speed, and timing are controlled by the device to adjust the participant's soleus response. Four-to-five walking bouts are conducted interleaving perturbed and unperturbed walking steps (until collecting data of about 30 perturbed and unperturbed steps per walking bout) leaving at least one unperturbed step before a perturbed step. Changes in the soleus EMG will be compared between perturbed and unperturbed walking steps.