Knee valgus during drop jumps in National Collegiate Athletic Association Division I female athletes: the effect of a medial post.
BACKGROUND
Female athletes land from a jump with greater knee valgus and ankle pronation/eversion. Excessive valgus and pronation have been linked to risk of anterior cruciate ligament injury. A medially posted orthosis decreases component motions of knee valgus such as foot pronation/eversion and tibial internal rotation.


OBJECTIVE
We hypothesized a medial post would decrease knee valgus and ankle pronation/eversion during drop-jump landings in NCAA-I female athletes.


METHODS
Controlled laboratory study.


METHODS
Knee and ankle 3-dimensional kinematics were measured using high-speed motion capture in 10 National Collegiate Athletic Association Division I female athletes during a drop-jump landing with and without a medial post. Analysis of variance was used to determine differences in posting condition, t tests were used to determine dominant-nondominant differences, and the Pearson correlation coefficient was used to determine relationships between variables.


RESULTS
Significant differences were found for all measures in the posted condition. A medial post decreased knee valgus at initial contact (1.24 degrees , P < .01) and maximum angle (1.21 degrees , P < .01). The post also decreased ankle pronation/eversion at initial contact (0.77 degrees , P < .01) and maximum angle (0.95 degrees , P = .039).


CONCLUSIONS
The authors have demonstrated a significant decrease in knee valgus and ankle pronation/eversion during a drop jump with a medial post placed in the athletes' shoes.


CONCLUSIONS
A medial post may be a potential means to decrease risk of anterior cruciate ligament injury.
Joseph
Michael
M
Department of Kinesiology, University of Connecticut, Storrs, Connecticut, USA. mickpt@sbcglobal.net
Tiberio
David
D
Baird
Jennifer L
JL
Trojian
Thomas H
TH
Anderson
Jeffrey M
JM
Kraemer
William J
WJ
Maresh
Carl M
CM
D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009989:Orthotic Devices; D012399:Rotation; D012775:Shoes; D013177:Sports / Q000502:physiology*