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Females recruit quadriceps faster than males at multiple knee flexion angles following a weight-bearing rotary perturbation

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
David H. Perrin, Provost and Executive Vice Chancellor (Creator)
Sandra J. Shultz, Associate Professor (Contributor)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/

Abstract: Objective: To compare the effect of knee angle on muscle response times and neuromuscular recruitment patterns between sexes following a perturbation in single leg stance at 10°, 20°, and 30°. We hypothesized that response times would be faster at lesser knee flexion angles and that females would recruit their quadriceps faster than males at all angles. Design: A repeated-measures design. Setting: Motion analysis laboratory. Participants: Twenty (10 female; 10 male) healthy, recreationally active volunteers. Interventions: A rotary perturbation in single leg stance. Outcome Measurements: Response times of the medial and lateral quadriceps, hamstrings, and gastrocnemius. Results: There was a trend toward faster response times for all muscles closer toward extension. A consistent neuromuscular recruitment pattern for both males and females was evident for each knee angle tested. Females, however, contracted their quadriceps faster than males at all knee flexion angles. Conclusions: Small changes in knee angle near extension do not alter muscle response times and hence neuromuscular recruitment patterns in males and females. Regardless of knee flexion angle, following a perturbation in single leg stance, females contract their quadriceps faster than males. Clinical Relevance: Earlier contraction of the quadriceps in females may increase anterior tibial translation and hence anterior cruciate ligament strain, thereby heightening injury risk.

Additional Information

Publication
Clinical Journal of Sports Medicine, 15(3), pp.167-171
Language: English
Date: 2006
Keywords
Anterior cruciate ligament, Knee angle, Perturbation, Reflex