Thesis (M.S.)--University of Akron, Dept. of Civil Engineering, 2009. / "May, 2009." Title from electronic thesis title page (viewed 8/2/2009) Advisor, Ping Yi; Committee members, William H. Schneider IV, Anil Patnaik; Department Chair, Wieslaw K. Binienda; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Fatigue has been observed to affect lower extremity mechanics during the cutting maneuver. However, there is a lack of research examining the effect of fatigue and limb dominance on lower extremity mechanics during unanticipated sidecutting. Objectives: This research sought to assess mechanical differences pre- and post-fatigue and with respect to limb dominance. Design: Repeated measures. Methods: Thirteen female collegiate soccer and field hockey players performed right and left unanticipated sidecutting following the Yo-Yo Intermittent Recovery test (Yo-Yo IR), a two minute treadmill run at a predicted VO2max, and maximum vertical jumps. Mechanical measures of ankle, knee, and hip motion were obtained during the stance phase of the cut. Repeated measures 2x2 ANOVAs were performed to look at fatigue and limb differences. Alpha level set a priori at 0.05. Results: At initial contact and peak stance, significant changes pre- to post-fatigue were observed. At initial contact there was a reduction in knee flexion angles along with increased ankle dorsiflexion angles postfatigue. At peak stance: increased knee adductor moments post-fatigue; greater ankle eversion moments on the dominant limb (DL) as well as increased eversion moments post-fatigue for both limbs. There was a differential effect of fatigue on peak hip abduction angles and hip internal rotation angles at initial contact which were altered in the DL only; decreased hip adductor moments occurred post-fatigue as well as decreased power absorption. Conclusions: Results from this study indicate that lower extremity mechanics are altered as an effect of fatigue such that injury risk may be elevated. / School of Physical Education, Sport, and Exercise Science

The purpose of this study was to examine the relationship between leg dominance and knee mechanics to provide further information about the etiology of ACL injury. Sixteen healthy females between the ages of 18 and 22 who were NCAA Division I varsity soccer players participated in this study. Subjects were instructed to perform a cutting maneuver; where they sprinted full speed and then performed an evasive maneuver (planting on one leg and pushing off to the other leg in a new direction) at a 45° angle with their dominate leg (DL) and non-dominate leg (NDL). Subjects were required to perform five successful cuts on each side given in a random order. Bilateral kinematic and kinetic data were collected during the cutting trials. After the cutting trials, subjects performed bilateral isometric and isokinetic testing using a Cybex Norm dynamometer at a speed of 60°/sec to evaluate knee muscle strength. During the braking phase the NDL showed greater (P=0.003) power absorption, greater (P=0.01) peak internal rotation angle and greater (P=0.005) peak flexion velocity. During the propulsive phase the DL showed greater (P=0.01) power production, greater (P=0.038) peak internal adductor moment and greater (P=0.02) peak extension velocity. In addition, no differences (P>0.05) in knee extensor and flexor isometric and isokinetic torques between the two limbs were shown. The results of this study show that a difference in knee mechanics during cutting does exist between the DL and NDL. The findings of this study will increase the knowledge base of ACL injury in females and aid in the design of more appropriate neuromuscular, plyometric and strength training protocols for injury prevention. / School of Physical Education, Sport, and Exercise Science

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references.