Changing spring stiffness in a shock-absorbing pylon on prosthetic mechanical work during walking
Advisor Information
Kota Takahashi
Location
MBSC 201
Presentation Type
Poster
Start Date
6-3-2020 2:00 PM
End Date
6-3-2020 3:15 PM
Abstract
A prosthetic shock-absorbing pylon (SAP) is intended to attenuate impact forces, provide comfort, and reduce pain for prosthesis users. However, the effect of SAP spring stiffness on mechanical work done by the prosthetic limb during walking remains unclear. The purpose of this study: to investigate the effects of spring stiffness and walking speed on the mechanical work of the prosthetic limb during stance in individuals with unilateral transtibial amputation (TTA). We hypothesized that: (1) a more compliant spring results in larger negative work during early stance, and subsequently produce larger positive work (i.e., greater energy stored and returned) and (2) increased walking speed will amplify the effects of SAP spring stiffness on mechanical work due to an increase in ground reaction forces. A secondary analysis was performed on 12 unilateral TTA participants, who walked overground on four spring stiffnesses at self-selected customary (1.22±0.01m/s) and fast (1.53±0.01m/s) walking speeds. Joint power and work were calculated using the unified deformable power analysis. Total limb power was estimated as the sum of the prosthesis, knee, and hip power. The stance phase was divided into four phases defined by the fluctuations of negative and positive work done by the total limb: (1) collision (0-20% of stance), (2) rebound (20-54%), (3) preload (54-82%), and (4) push-off (82-100%). Greater magnitude of negative work to positive work from the prosthesis suggests a damping effect. Future research will investigate the source of this net energy loss from the prosthesis its influence on the contralateral limb.
Changing spring stiffness in a shock-absorbing pylon on prosthetic mechanical work during walking
MBSC 201
A prosthetic shock-absorbing pylon (SAP) is intended to attenuate impact forces, provide comfort, and reduce pain for prosthesis users. However, the effect of SAP spring stiffness on mechanical work done by the prosthetic limb during walking remains unclear. The purpose of this study: to investigate the effects of spring stiffness and walking speed on the mechanical work of the prosthetic limb during stance in individuals with unilateral transtibial amputation (TTA). We hypothesized that: (1) a more compliant spring results in larger negative work during early stance, and subsequently produce larger positive work (i.e., greater energy stored and returned) and (2) increased walking speed will amplify the effects of SAP spring stiffness on mechanical work due to an increase in ground reaction forces. A secondary analysis was performed on 12 unilateral TTA participants, who walked overground on four spring stiffnesses at self-selected customary (1.22±0.01m/s) and fast (1.53±0.01m/s) walking speeds. Joint power and work were calculated using the unified deformable power analysis. Total limb power was estimated as the sum of the prosthesis, knee, and hip power. The stance phase was divided into four phases defined by the fluctuations of negative and positive work done by the total limb: (1) collision (0-20% of stance), (2) rebound (20-54%), (3) preload (54-82%), and (4) push-off (82-100%). Greater magnitude of negative work to positive work from the prosthesis suggests a damping effect. Future research will investigate the source of this net energy loss from the prosthesis its influence on the contralateral limb.