Abstract
OBJECTIVE: This study aims to investigate whether alterations in the lower extremity kinematics, kinetics, and muscle activity of individuals with chronic ankle instability (CAI) occur during landing with expected and unexpected inversion perturbations. METHODOLOGY: PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases were searched for relevant studies up to November 30, 2024. Comparative studies investigating the characteristics of lower extremity kinematics, kinetics, and muscle activity in individuals with CAI compared with healthy controls were included. Two independent reviewers extracted the data. Certainty of the evidence was assessed using the Newcastle-Ottawa Scale (NOS) approach. SYNTHESIS: Thirteen studies involving 207 patients with CAI and 215 healthy controls were included. Individuals with CAI exhibited increased activity of the tibialis anterior muscle before landing (SMD = 0.28 and 95% CI: 0.03-0.54). The delayed activation of the peroneus longus muscle (SMD = 1.35 and 95% CI: 0.90-1.80) and increased co-contraction index in the sagittal plane (SMD = 0.41 and 95% CI: 0.06-0.77), ankle inversion angle (SMD = 0.56 and 95% CI: 0.30-0.81), ankle inversion range of motion (SMD = 0.83 and 95% CI: 0.42-1.24), and knee extension moment (SMD = 0.71 and 95% CI: 0.32-1.11) were observed after landing. Besides, subgroup analysis revealed that the anticipation of perturbations influenced muscle activation patterns, with significant differences in peroneus longus latency and coactivation indices. CONCLUSION: Patients with CAI may present differences in lower extremity biomechanics during expected and unexpected inversion-perturbed landings compared with healthy controls. The results of this work may have clinical implications in the development of more effective and targeted rehabilitation programs for individuals with CAI. TRIAL REGISTRATION: PROSPERO registration number: CRD42024615006.