High- and low-arched feet have long been thought to function differently. The purpose of this study was to investigate the relationship between arch structure and lower extremity mechanics in runners with extreme pes planus and pes cavus. It was hypothesized that low-arched individuals would exhibit an increased rearfoot eversion excursion, eversion/tibial internal rotation ratio, and increased angular velocity in rearfoot eversion when compared to high-arched runners. In addition, it was hypothesized that high-arched runners would exhibit greater vertical loading rates. Twenty high-arched and 20 low-arched runners with histories of running-related injuries were included in this study. Low-arched runners were found to have increased rearfoot eversion excursion, eversion to tibial internal rotation ratio, and rearfoot eversion velocity. High-arched runners had increased vertical loading rate when compared to low-arched runners. These results suggest that arch structure is associated with specific lower extremity kinematics and kinetics. Differences in these parameters may subsequently lead to differences in injury patterns in high-arched and low-arched runners.
D.S. Williams, Dept. of Physical Therapy, East Carolina U., Greenville, NC 27858-4353; I.S. McClay, Joyner Sportsmedicine Institute, Harrisburg, PA 17111, and Motion Analysis Lab, U. of Delaware, Newark, DE 19716; J. Hamill, Dept. of Exercise Science, UMass, Amherst, MA 01003; T.S. Buchanan, Center for Biomedical Engineering Research, U. of Delaware.