Meeting Abstract

P1.161  Monday, Jan. 4  Mechanical properties of rat hindlimbs during locomotion DAWSON, Tricia*; JINDRICH, Devin L; Arizona State University; Arizona State University tadawson@asu.edu

Rodents, and rats in particular, are currently the preferred animal model used to study neuromotor injuries such as spinal cord injury. Despite the fact that locomotion is the most common functional assessment used, the mechanics and motor control of rodent locomotion have not been extensively studied. For example, although at high speeds rats exhibit whole-body spring-mass mechanics, it is unclear whether rats exhibit inverted-pendulum dynamics at low speeds similar to other quadrupeds. Moreover, the mechanical leg and joint mechanics during rat locomotion have not been extensively described. We measured kinematics and single-leg force production during running in laboratory rats to characterize joint- and limb-level mechanics. Rats ran along a horizontal trackway in which a small force platform (AMTI HE 6×6) was mounted. Ground-reaction forces from individual hindlimb steps were recorded. Video recording of leg and body markers using two cameras allowed for three-dimensional analysis of leg and joint mechanics. Preliminary results suggest that rat legs are compliant over a wide range of speeds. The results from these experiments will provide specific control targets for impedance-based functional electrical stimulation systems currently under development using a rodent model.