Category: Winner – Undergraduate

It is common thought that structural asymmetries result in a running disadvantage, and that anatomical and mechanical symmetry is the preferred condition. Our opposition to this stance began in observation of Usain Bolt, who exhibits a 13% force difference in striking with his right versus left leg due to a leg length difference. But there are few studies on gait asymmetries to explain this phenomenon: how can the fastest man in history be asymmetrical? To investigate this, we have created a study in which we lengthen the right leg of athletes and observe the response of both legs. We propose that the body compensates by altering vertical force and contact time in the opposing limb, resulting in an adjustment to both legs. Our subjects ran a control and experimental condition where an 27mm insert was attached to the right shoe at 3, 4, 5, and 6m/s. We hypothesized that the lengthened leg would have a decreased vertical ground reaction force and increased contact time and the unlengthened leg would have an increased vertical ground reaction force and decreased contact time. We further hypothesized that the two-leg average would not change between conditions. We determined both hypotheses to be correct. These findings show that asymmetries are not an inherent disability, but rather, functional asymmetries can increase the body's effectiveness in motion.