Stair descent biomechanics reflect perceived instability in people with unilateral ankle sprain history

Background: Efforts have been exerted to establish the correlation between objective variables and subjectively perceived ankle instability. Whether or not biomechanical parameters during stair descent can serve as potential assessment tools for perceived stability in people with unilateral ankle sprain history is unknown.

Methods: Twenty-four subjects with unilateral ankle sprain history were categorized into four groups according to the severity of perceived stability during stair descent. Kinematic and kinetic parameters during stair descent were obtained with a motion analysis system. Spearman's correlation coefficient (ρ) was utilized to test the correlation between the score of perceived stability during stair descent and biomechanical variables.

Findings: Subjects with increased perceived instability were likely to show increased ankle inversion (ρ = -0.46, p = .025) and increased ankle plantarflexion (ρ = 0.46, p = .025), with increased hip adduction (ρ = -0.43, p = .036), hip flexion (ρ = -0.56, p = .004), knee adduction (ρ = 0.45, p = .027), and knee flexion (ρ = -0.44, p = .031). No significant correlation was detected between kinetic variables and perceived stability.

Interpretation: Sagittal and coronal plane motions of the ankle might require rehabilitative intervention to produce improved self-reported outcomes. Kinematic assessment during stair descent can aid in the quantification of subjective ankle instability.