Alex Chaney – Mechanical Engineering

Understanding How Humans Learn to Walk with a Unilateral Prosthesis

Humans learn to walk at a young age, often at around the age of one year old. As they grow older, humans continue to develop their walking patterns until they mature. These walking patterns may change due to external reasons such as injuries, disease, and more. Understanding such changes would inform approaches to rehabilitation after such injury or disease. In some situations, such as after an amputation, humans may need to re-learn how to walk with the new prosthetic device. To address these issues, it is important to understand how humans learn to walk and how human walking changes under different conditions. Due to the young age that humans learn to walk, it is difficult to study the original stages of learning. Here, we recreate the initial learning process of walking for a short period of time by studying how (non-amputee) humans wearing the iWALK 2.0 unilateral prosthesis learn to walk. We collected data from N = 10 subjects, after informed consent and IRB approval. Each subject was equipped with light reflective markers on the abdomen, both the left and right foot, shank and hip. The markers were used to track movements with a Vicon motion capture system. Subjects walked on a treadmill equipped with a left and right force plate to measure the ground reaction forces and torques during each trial. Data was collected from each subject walking without the device for roughly three minutes and with the device attached to the right leg for roughly 20 minutes. All subjects had an asymmetric walking patterned without wearing the device, relative to the force data. While using the device, all subjects walked more heavily on their left leg (leg without the device). While wearing the device, the free leg endured an average of 65% of the weight. Roughly half the subjects walked more heavily on their free leg during the early stages of the procedure when the walking speed was 0.3 m/s. Analysis of horizontal forces and capture data to come. Overall, through data analysis and subject feedback, 9/10 of the participants believed they performed better by the end of the trial.

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