Abstract
Despite a considerable amount of research, the deficits causing recurrent sprains
in people with chronic ankle instability are still unclear. Changes in frontal plane
kinematics and decreased peroneal activation have been proposed as potential underlying
mechanisms, but whether people with ankle instability show deficits in control of
injury-relevant movements is not well understood. Therefore, the purpose of the present
study was to analyse ankle joint kinematics and kinetics as well as neuromuscular
activation during dynamic change-of-direction movements. Eighteen participants with
functional instability, 18 participants with functional and mechanical instability
and 18 healthy controls performed 45° sidestep-cutting and 180° turning movements
in reaction to light signals. During sidestep-cutting both instability groups displayed
significantly lower inversion angles than controls when the trials with the highest
maximum inversion angle of each participant were compared. In turning movements, participants
with functional instability presented significantly lower average maximum inversion
angles than controls as well as higher peroneal activation before foot strike than
participants with both functional and mechanical instability. We theorize that the
observed changes in movement kinematics of participants with chronic ankle instability
are the result of a protective strategy to limit frontal plane ankle joint loading
in potentially harmful situations.
Key words
ankle injuries - biomechanics - cutting movements
