The effects of misalignment of the center of rotation of the ankle on stiffness measurements

Author

Schmidt, B.D. ; Given, Joseph D. ; Dewald, Julius P A

Author_Institution

Sensory Motor Performance Program, Rehabilitation Inst. of Chicago, IL, USA

Volume

4

fYear

1997

fDate

30 Oct-2 Nov 1997

Firstpage

1841

Abstract

Misalignment of the center of rotation of the ankle with the axis of rotation of an actuator results in significant error in measured ankle torque during passive ranging of the ankle. As a result, estimates of ankle stiffness must account for this misalignment torque. We quantified misalignment torques and foot plate forces in the human ankle with measured displacements in two orthogonal directions. The resulting foot plate forces were consistent with the forces predicted by the mechanics of the system. These data will be used to align the center of rotation of the ankle with the actuator axis of rotation. This alignment procedure will improve the validity of experimental comparisons when monitoring longitudinal changes in the mechanical properties of the ankle following spinal cord injury

Keywords

biomechanics; biomedical measurement; measurement errors; patient rehabilitation; rotation; torque measurement; actuator axis of rotation; ankle center of rotation; foot plate forces; longitudinal changes; mechanical properties; misalignment effects; misalignment errors; misalignment torque; orthogonal directions; passive ranging; rehabilitation testing; spinal cord injury; stiffness measurements; Actuators; Anthropometry; Displacement measurement; Foot; Force measurement; Humans; Mechanical factors; Monitoring; Rotation measurement; Torque measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Engineering in Medicine and Biology Society, 1997. Proceedings of the 19th Annual International Conference of the IEEE

Conference_Location

Chicago, IL

ISSN

1094-687X

Print_ISBN

0-7803-4262-3

Type

conf

DOI

10.1109/IEMBS.1997.757090

Filename

757090