Designing Active Assistance for Gait With Hip Abductors Weakness Using Predictive Simulation.

Area of Science:

• Biomechanics
• Robotics
• Human Movement Science

Background:

• Weak hip abductors lead to compensatory gait patterns.
• These patterns increase fall risk and reduce walking efficiency.
• Understanding these effects is crucial for rehabilitation and assistive device design.

Purpose of the Study:

• Investigate the influence of hip abductor weakness on gait.
• Evaluate the effectiveness of ideal hip abduction assistive torque in normalizing gait.
• Optimize assistive torque parameters for improved gait patterns.

Main Methods:

• Utilized a predictive simulation framework with a full-body musculoskeletal model.
• Simulated reduced hip abductor muscle strength to mimic weakness.
• Applied ideal hip abduction assistive torque with step, trapezoid, and biological profiles, optimizing timing and magnitude via bilevel optimization.

Main Results:

• The simulation successfully captured key features of compensatory gait patterns associated with hip abductor weakness.
• All tested assistive torque profiles effectively normalized gait kinematics.
• The trapezoid and biological profiles demonstrated comparable efficacy in normalizing kinematics and reducing the cost of transport, with the trapezoid profile being simpler and highly effective.

Conclusions:

• Hip abductor weakness significantly impacts gait, necessitating compensatory strategies.
• Hip abduction assistive torque shows potential for gait normalization.
• The trapezoid torque profile is a promising, efficient option for exoskeleton control design in individuals with hip abductor weakness.