Meeting Abstract

P3.60  Tuesday, Jan. 6  Limb function during gait initiation in dogs STOVER, K.K.*; BIKNEVICIUS, A.R.; Ohio U. Honors Tutorial College; Ohio U. College of Osteopathic Medicine ks216405@ohio.edu

The triggers for gait changes, such as the progression from a walk to a run, have been explored extensively in humans and some quadrupeds. Published reports focus on the mechanics of the center of mass (COM) without exploring how individual limbs contribute to gait transition. The purpose of this study is to distinguish the roles of the forelimbs and hind limbs in the ultimate gait transition, namely, gait initiation (from standstill to walk). Understanding the simplest form of gait transitions may lead to greater insight into the more complex transitions that occur at higher speeds. Seven Labrador Retrievers (22.2-51.3 kg) were recruited to take part in the study. A Kistler force platform was used to capture the vertical, craniocaudal and mediolateral ground reaction forces of individual limbs during gait initiation. We analyzed peak vertical force, vertical impulse and propulsive impulse in trials with squared initial postures. The gait initiator (first limb to move) was a hind limb in 75% of the trials; subsequent limb liftoffs followed a lateral sequence pattern (e.g., right hind, right fore, left hind, left fore). The gait initiator hind limb was unloaded with almost no propulsive effort, and the ipsilateral forelimb showed a similar pattern. This effectively shifted the body weight contralaterally away from the gait initiator side, increasing the vertical support roles of the contralateral limbs. The contralateral limbs, with both the hind limbs and forelimbs acting equally, generate nearly all of the initial propulsive effort for gait initiation.