The Effects of Functional Fatigue on Ground Reaction Forces of a Jump, Land, and Cut Task in Female Collegiate Soccer Athletes

Publication Date


Type of Culminating Activity


Degree Title

Master of Science in Sports and Exercise Studies, Biophysical Emphasis



Major Advisor

Chad Harris


Ron Pfeiffer


Mark DeBeliso


Since the implementation of Title IX in 1972, the number of females participating in athletics has risen dramatically. The number of injuries has risen in accordance with the athletic population influx. Many injuries can be explained by the population explosion; however, injury to the anterior cruciate ligament (ACL) is one of the few injuries women seem more susceptible to compared to their male counterparts. Sports such as football, soccer, volleyball, baseball, and basketball involve rapid jumping, repetitive stop and go movements, and sudden changes of direction. The purpose of this study was to determine the effects of fatigue on jump, land, and cut kinetics in female collegiate soccer athletes to examine if an increased risk of ACL injury potential exists. Female athletes tend to be quadriceps dominant suggesting a muscular imbalance between the strength of the quadriceps and hamstring muscles. These biomechanical imbalances are believed to decrease shock absorption and knee stabilization during landing. Several studies have suggested landing kinetics can be altered with the introduction of fatigue; however, these studies generally involve only single muscle fatigue induced with the use of an isokinetic dynamometer rather than functional fatigue protocol. As a result, the ability to generalize these results to the rapid movements performed in athletics is minimal. As such, this study utilized a rapid sprint fatigue protocol to simulate an applied sports model. The hypothesis was soccer athletes will not land differently following a functional fatiguing protocol of rapid acceleration, deceleration, and change of direction than the athletes would in the absence of fatigue eliciting exercise. The independent variable was fatigue. The dependent variables were peak anterior/posterior ground reaction forces during landing and push-off; peak medial/lateral ground reaction forces during landing and push-off; and peak vertical ground reaction force during landing and push-off. A repeated measure analysis of variance was be used to demonstrate significance at a level of p ≤ 0.05.

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