Biomechanical Abnormalities in Both Sides of Individuals With Unilateral Chronic Ankle Instability During...

Individuals with unilateral chronic ankle instability (CAI) exhibit bilateral sensorimotor deficits, but whether these deficits contribute to bilateral biomechanical abnormalities remains unclear.

To evaluate bilateral ankle biomechanics in individuals with CAI during unanticipated jumps.

Controlled laboratory study.

Eighteen individuals with unilateral CAI and 18 healthy controls were recruited to perform unanticipated jumps. Kinematic and kinetic data from both ankles during unanticipated jumps were simultaneously collected using an infrared high-speed motion capture system (T40, 200 Hz; Vicon) and 3-dimensional force platforms (1000 Hz; Kistler). The interactions and main effects were analyzed by statistical parametric mapping with 2-way repeated measures analysis of variance.

The injured side of CAI exhibited greater ankle plantarflexion (9.5%-36.7%; P = .01) and inversion (0%-8.7%; P = .033) angles, vertical ground-reaction force (0%-2.8% [P = .045]; 18.6%-30% [P = .013]), and smaller eversion moment (93.4%-100%; P = .035). Additionally, the uninjured side of CAI showed lower ankle dorsiflexion (41.8%-100%; P = .01) and eversion (56%-70%; P = .025) angles and moment (3.6%-40% [P = .002]; 92.1%-100% [P = .044]) but higher vertical ground-reaction force (0%-1.8%; P = .049).

The study showed that the injured and uninjured sides of CAI demonstrate biomechanical characteristics associated with increased risk of ankle sprain, suggesting that management strategies should target both ankles. These findings may help in understanding and preventing ankle sprains. Further studies are needed to identify these risks.

Unilateral CAI may elevate the risk of ankle sprains bilaterally.