John D Willson

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BACKGROUND Patellofemoral pain is commonly associated with lower extremity joint rotations that decrease retropatellar contact area and subsequently increase retropatellar stress during weightbearing activities. People with patellofemoral pain are thought to be capable of avoiding such harmful mechanics during activities with low external demands. However,(More)
STUDY DESIGN Cross-sectional. OBJECTIVES To determine if females with anterior knee pain are more likely to demonstrate hip abduction or external rotation weakness than a similar, asymptomatic, age-matched control group. BACKGROUND Diminished hip strength has been implicated as being contributory to lower-extremity malalignment and patellofemoral pain.(More)
INTRODUCTION/PURPOSE Decreased lumbo-pelvic (or core) stability has been suggested to contribute to the etiology of lower extremity injuries, particularly in females. This prospective study compares core stability measures between genders and between athletes who reported an injury during their season versus those who did not. Finally, we looked for one or(More)
Invasive species represent a significant threat to global biodiversity and a substantial economic burden. Burmese pythons, giant constricting snakes native to Asia, now are found throughout much of southern Florida, including all of Everglades National Park (ENP). Pythons have increased dramatically in both abundance and geographic range since 2000 and(More)
INTRODUCTION/PURPOSE Muscles of the trunk, hip, and knee influence the orientation of the lower extremity during weight bearing activities. The purpose of this study was threefold: first, to compare the orientation of the lower extremity during a single leg (SL) squat among male and female athletes; second, to compare the strength of muscle groups in the(More)
Successful invasions of secretive alien species often go unrecognized until spread has exceeded the point where control or eradication is feasible. In such situations, understanding factors that contributed to establishment can be critical to preventing subsequent introductions of previously-successful invaders or ecologically similar species. The Burmese(More)
PURPOSE The purpose of this investigation was to identify changes in loading characteristics of the foot associated with fatigue during running. METHODS Nineteen healthy subjects ranging from 20 to 30 yr (mean = 22.3, SD = 2.4) were equipped with the Pedar in-shoe measurement system (Novel GmbH) for the assessment of plantar loading. After acclimation to(More)
STUDY DESIGN Case-control study of females with patellofemoral pain syndrome (PFPS) and a control group. OBJECTIVES Three different approaches were used to examine the utility of a 2-dimensional (2-D) frontal plane projection angle (FPPA) measure of knee alignment. First, we measured the FPPA association with respect to 3-dimensional (3-D) lower extremity(More)
CONTEXT Lower extremity (LE) weakness might be associated with altered mechanics during weight bearing in subjects with patellofemoral pain syndrome (PFPS). OBJECTIVE To analyze LE strength, mechanics, and the association between these variables among women with and without PFPS during a simulated athletic task. DESIGN Case control. SETTING(More)
PURPOSE The purpose of this study was to determine whether walking with poles reduces loading to the lower extremity during level over ground walking. METHODS Three-dimensional gait analysis was conducted on 13 healthy adults who completed 10 walking trials using three different poling conditions (selected poles, poles back, and poles front) and without(More)