Term of Award

Spring 2004

Degree Name

Master of Science in Kinesiology

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Committee Chair

Bryan L. Riemann

Committee Member 1

Josh Drouin

Committee Member 2

Barry A. Munkasy

Abstract

Lower extremity hop tests are commonly used to assess return to play criteria. Lower extremity hop tests are commonly begun with anterior hops for distance and time, and then gradually move to cross-over hops for distance and time using a 15 cm cross-over. It is thought that the 15 cm cross-over hop is an optimal distance to stimulate excess forces on the lower extremity when compared to the anterior hop. When the athlete is able to complete the cross-over hops successfully, it is thought that they are able to return to play in their given sport. A problem with this assumption is that all literature to date has looked at outcome measures (distance hopped), and not the actual forces being administered on the lower extremity (ground reaction forces; GRF). Thus, the purpose of this study is to compare the vertical, anterior/posterior, and medial/lateral GRF between two lower extremity hop variations, the anterior and cross-over hops for distance.

Thirty-eight Georgia Southern athletes who volunteered to perform both the take-off and landing phases of the anterior and cross-over hops for distance. Ground reaction force data was collected during each task. Paired t-Tests were used to compare ground reaction characteristics between the two hop variations, with the alpha level conservatively set at .001. Results revealed significant differences (P<.001) during the peak and average GRF as well as impulse during the cross-over hop as compared to the anterior hop. No differences were noted between the vertical and anterior peak and average GRF and impulse. These results suggest that the 15 cm distance used in the cross-over hop is sufficient to increase the medial/lateral forces on the lower extremity. Further research needs to be focused on the forces induced on the individual joints of the lower extremity, assessing where the majority of the forces are being applied, and how an injured individual is able to cope with such forces.

Copyright

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