<![CDATA[MS Defense by Arshad Mandani]]>

Committee:
Aaron Young, PhD (Georgia Institute of Technology)
Zachary Graham, PhD (Institute for Human and Machine Cognition)

Title: ExerExo: Exploring the Effects of Assistive and Resistive Ankle Exoskeleton Torque on Walking Mechanics and Energetics

In recent years, wearable robotics have emerged as powerful tools to improve human mobility, most commonly by assisting movement and reducing the effort required. But what if these same devices could be used to increase effort and turn mobility aids into exercise machines?

While the field has primarily focused on assistive applications, recent interest has grown around the potential for resistive exoskeleton strategies to increase physical effort and mechanical work across physiological, mechanical, and neuromuscular levels for the purpose of targeted rehabilitation, muscle strengthening, and exercise. This thesis explores the use of a powered ankle exoskeleton capable of applying both assistive and resistive ankle-joint torque during treadmill walking. The objective is to examine how modulating ankle torque direction and walking speed affects biomechanical performance, physiological effort, and perceived exertion with implications for exercise training. Key outcome measures include heart rate, metabolic energy expenditure, subjective ratings of perceived exertion, ankle joint mechanics, and muscle activation patterns.

Results suggest that applying resistive torque at lower walking speeds can evoke physiological and perceptual responses similar to those experienced during higher-speed walking with assistive torque. This indicates the potential for tailoring exercise intensity and volume through exoskeleton control, enabling comparable training loads across a diverse set of movement conditions. The findings underscore the potential for integrating ankle exoskeletons into exercise science, rehabilitation, and human performance applications, where precise control over joint-level torque can be leveraged to meet individualized training goals.