Spatiotemporal gait adaptations to mediolateral optical flow perturbations in athletes following anterior cruciate ligament reconstruction

Optical flow perturbation is an emerging approach for gait assessment that simulates sport-specific visual challenges and may reveal gait adaptations in athletes after anterior cruciate ligament reconstruction (ACLR). This study aimed to compare the effects of mediolateral (ML) optical flow perturbations on spatiotemporal gait parameters in athletes with ACLR and healthy controls. Eighteen athletes with ACLR and 18 matched healthy controls participated. Spatiotemporal gait parameters, including mean and variability of step width (SW), step length (SL), and step time (ST), as well as cadence, were recorded using a Vicon motion capture system during treadmill walking in a virtual hallway under unperturbed and ML optical flow perturbation conditions. Condition × Group interactions were evaluated using two-way repeated-measures ANOVA, with Holm correction for multiple testing across the seven gait outcomes. Before multiplicity adjustment, significant Condition × Group interactions were observed for SL ( p = 0.016), ST ( p = 0.023), and cadence ( p = 0.018). However, none of the seven interactions remained statistically significant after Holm correction (all adjusted p ≥ 0.112). Significant main effects of condition were observed for SL ( p = 0.013), ST (p = 0.014), cadence ( p = 0.021), and the variability of SW ( p < 0.001), SL ( p = 0.028), and ST ( p = 0.047), whereas no significant condition effect was found for mean SW. Perturbed walking was associated with shorter SL and ST, increased cadence, and greater variability in the measured spatiotemporal parameters. ML optical flow perturbations were associated with changes in several spatiotemporal gait parameters and increased gait variability. However, after correction for multiple testing, the study did not establish statistically significant differences between athletes with ACLR and healthy controls in their gait responses to optical flow perturbations. Further research incorporating direct assessment of sensory function and comprehensive biomechanical measures is needed to clarify the mechanisms underlying gait adaptation to altered visual input and its potential relevance to recovery after ACLR.