Subject-Specific and COM Acceleration-Enhanced Reflex Neuromuscular Model to Predict Ankle Responses in Perturbed...

Area of Science:

• Biomechanics
• Neuroscience
• Robotics

Background:

• Subject-specific musculoskeletal models improve electromyography (EMG)-based joint torque estimation.
• Neuromuscular models (NMMs) incorporating center of mass (COM) states enhance muscle activation predictions for ankle torque during gait.
• Reflex controllers are crucial for active prosthetic and orthotic devices.

Purpose of the Study:

• To identify a subject-specific reflex NMM for locomotion using an EMG-calibrated musculoskeletal model.
• To evaluate the impact of COM acceleration on reflex NMM performance during perturbed gait.
• To assess the efficacy of subject-specific models and COM acceleration enhancement for ankle torque tracking.

Main Methods:

• Developed and employed subject-specific musculoskeletal models.
• Identified a reflex NMM using EMG data from unperturbed and perturbed gait.
• Implemented a COM acceleration-enhanced reflex NMM.
• Compared torque tracking accuracy between different model configurations.

Main Results:

• Subject-specific musculoskeletal models significantly improved ankle joint torque tracking in both unperturbed and perturbed gait.
• The COM acceleration-enhanced reflex NMM demonstrated superior ankle torque tracking, particularly in early stance and during backward perturbations.
• Model refinements led to more accurate predictions of joint torques.

Conclusions:

• Subject-specific musculoskeletal models and COM acceleration-enhanced reflex NMMs enhance the accuracy of joint torque estimation.
• These findings support the use of advanced NMMs for developing more responsive and effective active prosthetic and orthotic devices.
• The study provides a foundation for implementing sophisticated reflex controllers in assistive technologies.