Title: Kinematics and Muscle Activity During Landing on a Supinating Platform in
Persons with Ankle Instability
Abstract
Lateral ankle sprains are common injuries in athletic activity. Although most will resolve
with conservative treatment, others develop chronic Ankle Instability (AI), a condition
associated with persistent pain, weakness, and instability. Because of an increase in
prevalence of AI, considerable attention has been directed towards understanding the
underlying causes of this pathology. Despite the amount of research conducted in this
area, analysis of individuals with AI during dynamic conditions is limited. A detailed
kinematic and electromyographic analysis of the landing phase of a dynamic movement
pattern may give greater insight into the stresses placed on the foot and ankle complex in
AI subjects and how they differ from other populations. The aims of this study are to
determine if differences in preparatory EMG profiles, reactive EMG profiles, and
kinematics are present between the three groups (uninjured, coper, and AI) when landing
on a (1) non-supinating surface and a (2) supinating surface.
To address these aims, a three-dimensional motion analysis, combined with an
electromyographic analysis, during a dynamic landing on a custom supinating platform
will be conducted on 45 subjects. The subjects will be specifically recruited and divided
for comparison into three groups: 15 subjects with chronic ankle instability (AI), 15
subjects who have a previous history of at least one lateral ankle sprains and never
experienced recurrent symptoms (Copers), and 15 control subjects who are without a
history of a lateral ankle sprain (Control). A range of kinetic and electromyographic
variables will be extracted using techniques developed in previous studies. The variables
of interest will be analyzed to determine if there are differences between each subgroup
during a landing on a supinating and non-supinating platform. Accurately assessing foot
and ankle mechanics, along with muscle activations, can give insight into the
neuromuscular mechanism underlying ankle joint injuries, and the subsequent pathology
of AI. Once determined, future intervention studies can be performed to reduce the
incidence and severity of acute and chronic lateral ankle injury.