Year of Award

2015

Document Type

Professional Paper

Degree Type

Master of Science (MS)

Department or School/College

Department of Health and Human Performance

Committee Chair

Matthew Bundle

Commitee Members

Valerie Moody, Alex Danna-Dos Santos

Keywords

sprinting, top speeds, gait mechanics, vertical force

Subject Categories

Biomechanics | Exercise Physiology | Exercise Science | Sports Sciences

Abstract

Between individuals faster sprinting speeds are achieved by applying greater stance average forces against the running surface. Recent evidence further indicates that elite level performers also strike the ground with leg kinematics that differ from those of non-elites and that these leg movements act to enhance the force transients occurring in the milliseconds following foot-ground impact. I investigated whether sprint performance could be enhanced through a short term gait intervention, consisting of 3 laboratory training sessions wherein subjects (n = 6) completed 5 high-speed runs on an instrumented force treadmill at 90% of their measured top sprint. The subjects received immediate visual feedback of the previous bout of sprinting by reviewing the video record obtained from a laterally positioned camera with a frame rate of 1000 Hz. The subjects also received verbal cues throughout their participation, which were focused on encouraging leg postures more suitable for applying greater vertical forces into the ground. Incremental tests to top speed were administered on the force treadmill prior to and following the gait intervention. Paired sample t-tests were used to analyze the pre- vs. post-intervention variables which included; ground contact time, aerial time, swing time, stride time, and step length. Following the gait intervention top speeds increased by 6.7% [SD 1.3] and ground reaction forces increased by 0.03 xWb. 3D video analysis revealed that the velocity of the ankle and foot immediately before touchdown also increased by 7.3%. This permitted the leg to use a posture better able to apply the high vertical forces needed in the first half of stance. These data indicate that an acute training intervention can augment sprinting performance within a time frame that is too brief for the improvement to be attributed to changes within the musculature of the individual subjects. I conclude that running speed can be taught by providing knowledgeable cues that focus on the mechanics of the foot-ground impact.

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© Copyright 2015 Michelle Buechner