Lower-leg inertial properties in transtibial amputees and control subjects and their influence on the swing phase during gait.
OBJECTIVE
To identify the factors that constitute optimal inertial properties for a lower-limb prosthesis.


METHODS
Experimental, controlled; simulation using a subject-specific double-pendulum model based on individual kinematic data and leg inertial properties. Simulation outcomes were compared with gait analysis data.


METHODS
A gait laboratory.


METHODS
Ten transtibial amputees and 10 matched healthy controls.


METHODS
Not applicable.


METHODS
Inertial properties of the lower leg; kinematics and kinetics of the swing phase; and kinematics of double-pendulum model simulations.


RESULTS
In all amputees, inertial properties were reduced. No between-group differences existed in kinematics; hip and knee joint torques and powers were reduced in the amputees. Deviations between the double-pendulum model and experimental data were larger in the amputees than in the control subjects.


CONCLUSIONS
Although current lightweight prostheses have less optimal pendular behavior, their light weight requires smaller joint torques to influence the pendular trajectory. Therefore, optimal inertial properties, in terms of swing phase kinematics and kinetics, will be a compromise between pendular properties and efficient control.
Selles
Ruud W
RW
Institute of Rehabilitation Medicine, Erasmus University Rotterdam, Rotterdam, The Netherlands. rselles@northwestern.edu
Korteland
Sabine
S
Van Soest
A J
AJ
Bussmann
Johannes B
JB
Stam
Henk J
HJ
D000328:Adult; D000674:Amputees / Q000534:rehabilitation*; D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology; D008297:Male; D019415:Torque; D016138:Walking / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology