Abstract
Functional instability, i.e., recurrent sprains or a feeling of “giving way” of the
ankle, is common after ankle sprains. These patients have been supposed to have peroneal
muscle weakness based on manual methods for measuring muscle strength. We have confirmed
this theory by an isokinetic method for testing pronator muscle strength. Pronator
muscle weakness on the affected side was found among patients with unilateral functional
instability of the ankle joint. Impaired postural control was demonstrated by stabilometry
with the patient standing on either foot.
Key words
functional instability - ankle - pronator muscle - isokinetic torque
