Learning to walk with a robotic ankle exoskeleton.

Area of Science:

• Biomechanics
• Neuroscience
• Robotics

Background:

• Human locomotion involves complex muscular coordination.
• Disruptions to this coordination can reveal underlying neural adaptation mechanisms.
• Robotic exoskeletons offer a controlled method to perturb and study gait.

Purpose of the Study:

• To investigate human locomotor adaptation to altered muscular coordination using a muscle-controlled robotic exoskeleton.
• To examine how gait kinematics and muscle activity change with practice during exoskeleton-assisted walking.
• To assess the retention of adapted motor patterns over time.

Main Methods:

• Ten healthy subjects walked with a pneumatically powered ankle exoskeleton controlled by soleus muscle electromyography.
• The exoskeleton provided real-time plantar flexion assistance.
• Gait kinematics, muscle activity, and joint kinetics were measured during two separate testing sessions.

Main Results:

• Initially, exoskeleton power perturbed ankle movements, increasing plantar flexion during stance.
• Subjects reduced soleus muscle recruitment by ~35% with practice, adapting to use the exoskeleton for positive ankle work.
• Adapted motor patterns were retained between testing sessions separated by 3 days.

Conclusions:

• Muscle-controlled robotic exoskeletons can effectively disrupt and study human locomotor adaptation.
• Individuals can adapt their gait to exoskeleton assistance by modulating muscle activity.
• Robotic exoskeletons show promise as tools for investigating neural mechanisms of motor adaptation.