Lower Extremity Kinematics of a Single-Leg Squat with an Orthotic in Male and Female Collegiate Athletes

in Journal of Applied Biomechanics
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Kinematic differences have been linked to the gender discrepancies seen in knee injuries. A medially posted orthotic decreases frontal and transverse plane motions in the lower extremity during ambulation, squatting and landing. This study investigated the effect of a medial post on amount and timing of lower extremity motions during a single-leg squat in male and female athletes. We hypothesized there would be differences in these kinematic variables dependent upon sex and post conditions. Twenty male and female athletes performed single-leg squats with and without a five degree full-length medial post. Maximum joint angles were analyzed using a two-way, repeated-measures analysis of variance to determine if the differences created by post condition were statistically significant, whether there were gender differences, or interactions. Differences in maximum motion values and the time at which they occurred were found between men and women at the hip, knee and ankle. The post decreased all frontal plane measures in both sexes and resulted in earlier attainment of maximum ankle eversion and delayed maximum knee valgus. A medially posted orthotic may be beneficial not only in limiting motion, but in affecting the time in which stressful motions occur.

Michael F. Joseph and Kristin L. Holsing are each with the Kinesiology Department and the Physical Therapy Program, University of Connecticut, Storrs, CT. David Tiberio is with the Gray Institute, Adrian, MI. Address author correspondence to Michael F. Joseph at mickpt@sbcglobal.net.