| Non-contact
anterior cruciate ligament (ACL) injuries in female athletes remain
prevalent. Athletes with excessive foot pronation have been identified
to be at greater risk for non-contact ACL injury. Excessive foot pronation
has been linked to increased medial tibial rotation. Increased medial
tibial rotation heightens ACL strain and has been observed at or near
the time of ACL injury. Foot orthotics have been shown to decrease
medial tibial rotation during walking and running tasks. The effect
of a foot orthotic on activities that simulate a non-contact ACL injury
mechanism (i.e. landing) however is unknown. Therefore, the objective
of this study was to determine whether a foot orthotic was capable
of altering transverse plane lower extremity kinematics in female
athletes during landing. Twenty uninjured collegiate female athletes
participating in the sports of basketball, soccer or volleyball with
pes planus volunteered. Utilizing a repeated measures counterbalanced
design, subjects completed two landing tasks with and without a foot
orthotic using standardized footwear. The prefabricated orthotic had
a rigid shell and a 6 extrinsic rear-foot varus post. Dependent measures
included initial contact angle, peak angle, excursion and time to
peak angle for both the tibia and femur. Statistical analysis suggested
that the selected foot orthosis had little influence over lower extremity
transverse plane kinematics. Several factors including: the limitation
of a static measure to predict dynamic movement, inter-subject variability
and the physical characteristics of the orthotic device likely account
for the results. Future research should examine the influence of different
types of foot orthotics not only on lower extremity kinematics but
also tibiofemoral kinetics.
KEY
WORDS: ACL, hyperpronation, intervention, navicular drop, pes
planus.
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