Abstract:
The powered prosthetic foot (PPF) is designed to provide transtibial amputees (TTA) with
active propulsion and plantar flexion similar to that of the biological limb. Previous studies
have demonstrated the PPF’s ability to increase TTA walking speeds, while reducing the
energetic costs, however, little is known about its effects on dynamic balance control. The
purpose of this study was to assess dynamic balance control in a sample of TTA subjects
during level ground walking and obstacle-crossing tasks. Control subjects (n=5) and TTA
subjects (n=4) were instructed to complete a series of functional walking tasks during each lab
visit. The TTA subjects completed the walking protocol twice, first in their traditional passive
prosthetic foot and again in the prescribed PPF after two weeks of acclimation. Motion data
were collected via a 10-camera system with a 53-marker and 15-segment body model. Center
of mass (CoM) motion within the frontal plane were analyzed and used as functional
indicators of dynamic balance control. Preliminary findings from the study indicate that TTA
subjects wearing the PPF generally experienced a greater mediolateral CoM motion and peak
velocity, thus signifying a reduced ability to maintain dynamic balance control. Our findings
may be of particular interest to clinicians and PPF designers working to improve the amputee
population’s quality of life. Further data analysis is needed to support these initial findings.