Effect of Prosthetic Foot-Ankle Stiffness on Walking Performance in Transfemoral Prosthesis User
Session Number
2
Advisor(s)
Steven A. Gard, Northwestern University
Location
B115
Discipline
Medical and Health Sciences
Start Date
15-4-2026 11:10 AM
End Date
15-4-2026 11:55 AM
Abstract
The foot and ankle joint create a rocker mechanism, or roll-over shape (ROS), during walking that reduces vertical body motion and allows for efficient forward movement. In able-bodied individuals, the radius of the ROS stays consistent across different walking speeds because of adaptive ankle joint stiffness. However, prosthetic feet have a constant stiffness, so the ROS radius varies with walking speed. The purpose of this study is to determine how walking speed affects the ROS radius in above-knee prosthesis users as prosthetic foot-ankle stiffness is varied. We hypothesize that as an individual’s walking speed increases, the ROS radius will decrease due to the larger ground reaction forces applied to the prosthesis. Data was collected in a motion analysis laboratory as research subjects walked at three different speeds (slow, normal and fast) with five different stiffness combinations of keels and bumpers. Adjusting the ROS radius of prosthesis users to match able-bodied individuals should enable them to have a more comfortable and efficient gait, even during challenging tasks. The results of this work have important implications for the design of prosthetic foot-ankle components and for the prescription and fitting of technologies to improve mobility and quality of life for prosthesis users.
Effect of Prosthetic Foot-Ankle Stiffness on Walking Performance in Transfemoral Prosthesis User
B115
The foot and ankle joint create a rocker mechanism, or roll-over shape (ROS), during walking that reduces vertical body motion and allows for efficient forward movement. In able-bodied individuals, the radius of the ROS stays consistent across different walking speeds because of adaptive ankle joint stiffness. However, prosthetic feet have a constant stiffness, so the ROS radius varies with walking speed. The purpose of this study is to determine how walking speed affects the ROS radius in above-knee prosthesis users as prosthetic foot-ankle stiffness is varied. We hypothesize that as an individual’s walking speed increases, the ROS radius will decrease due to the larger ground reaction forces applied to the prosthesis. Data was collected in a motion analysis laboratory as research subjects walked at three different speeds (slow, normal and fast) with five different stiffness combinations of keels and bumpers. Adjusting the ROS radius of prosthesis users to match able-bodied individuals should enable them to have a more comfortable and efficient gait, even during challenging tasks. The results of this work have important implications for the design of prosthetic foot-ankle components and for the prescription and fitting of technologies to improve mobility and quality of life for prosthesis users.