A wheelchair modified for leg propulsion using voluntary activity or electrical stimulation

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Biomechanics

Background:

• Commercial wheelchairs modified for lower leg propulsion offer potential mobility and fitness benefits for users.
• Significant variability exists in user performance with leg-propelled wheelchairs, necessitating personalized approaches.
• Leg propulsion involves quadriceps (knee extensor) and hamstring (knee flexor) muscle activation, either voluntary or via electrical stimulation.

Purpose of the Study:

• To develop and validate a predictive model for leg-propelled wheelchair performance.
• To assess the model's ability to account for individual user variability.
• To explore the model's utility in optimizing wheelchair speed for specific users.

Main Methods:

• Modification of a commercial wheelchair for leg-based propulsion using a rotating footrest.
• Measurement of individual leg biomechanical properties: passive properties (stiffness, viscosity), active muscle properties (length-tension, force-velocity), and activation/fatigue rates.
• Integration of measured subject-specific parameters into a mathematical model of the leg-propelled wheelchair system.

Main Results:

• The developed model accurately predicted individual subject performance in leg-propelled wheelchair tasks.
• The model successfully incorporated subject-specific biomechanical data to explain performance variability.
• Initial findings suggest the model can be used for performance optimization.

Conclusions:

• A validated model can accurately predict leg-propelled wheelchair performance based on individual biomechanics.
• Personalized modeling can address user variability and optimize wheelchair design and control strategies.
• This approach holds promise for enhancing the effectiveness and user experience of leg-propelled mobility devices.