Meeting Abstract
The natural terrain of kangaroo rats is mainly comprised of sparse scrub across uneven desert hills. It is thought that these animals hop from scrub to scrub, requiring the ability to quickly accelerate while moving across uneven ground. Preliminary studies have suggested that kangaroo rats mainly increase speed via an increase in force production (decreased contact time) with relatively little change in contact length or hop frequency. Additionally, it appears that this pattern is maintained when hopping on an inclined plane. This increase in force production that results in an increase of speed has also been seen in humans, and could provide insightful correlations between human running and kangaroo rat hopping. Kangaroo rats were recorded while hopping on a treadmill at four set speed increments ranging from 1.64 m/s to 2.01 m/s over level, ten, and twenty degree incline. Their gait was then analyzed to determine the methods used to achieve speed increases on level and inclined terrain. Our results show that there is a significant difference between speed for contact time and peak ground reaction force, indicating that the kangaroo rats do alter the amount of force produced during a step cycle in order to increase their speed. Level hopping also resulted in a much higher stride frequency than the other inclines. Based on these results, it appears that kangaroo rat hopping mechanics are similar to those of human running.
