Original Research

Muscle Activity and Flexibility in Individuals With Medial Knee Displacement During the Overhead Squat

David R. Bell, PhD, ATC; Brian J. Vesci, MA, ATC; Lindsay J. DiStefano, PhD, ATC; Kevin M. Guskiewicz, PhD, ATC; Christopher J. Hirth, MS, PT, ATC; Darin A. Padua, PhD, ATC

  • Athletic Training and Sports Health Care
  • May/June 2012 - Volume 4 · Issue 3: 117-125
  • DOI: 10.3928/19425864-20110817-03
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Abstract

Functional movement analyses are commonly performed to evaluate for the risk of developing a knee or lower extremity injury. Conclusions are drawn about muscle strength, flexibility, and activation during these screenings based upon observed movement patterns. The purpose of this project was to compare range of motion (ROM), isokinetic strength, and muscle activity in individuals with and without excessive medial knee displacement (MKD) during a double-leg squat. Seventeen control participants and 14 participants with MKD had ankle and hip ROM and hip isokinetic peak torque assessed. Participants also had muscle activity of the gluteus maximus and adductor complex assessed during the descending and ascending phases of 5 consecutive double leg squats. The MKD group demonstrated decreased dorsiflexion ROM with the knee straight (P < .001), and increased adductor activation (P = .02) during the squat. These results indicate that gastrocnemius muscle tightness and increased adductor activity may cause excessive MKD.

AUTHORS

Dr Bell is from the Department of Kinesiology and the Department of Orthopedics and Rehabilitation, Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Madison, Wisconsin; Mr Vesci is from the Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, Massachusetts; Dr DiStefano is from the Department of Kinesiology, University of Connecticut, Storrs, Connecticut; and Dr Guskiewicz, Mr Hirth, and Dr Padua are from the Department of Exercise and Sports Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

This research was conducted at the Sports Medicine Research Laboratory at the University of North Carolina at Chapel Hill. The project was funded by the National Academy of Sports Medicine.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to David R. Bell, PhD, ATC, Department of Kinesiology, WisconsinInjuryinSportLaboratory,UniversityofWisconsin-Madison,2031Gymnasium-Natatorium, 2000 Observatory Drive, Madison, WI 53706; e-mail: drbell2@wisc.edu

doi: 10.3928/19425864-20110817-03

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