Effect of Cognitive Load on the Range of Motion of Lower Limb Joints During Walking in Men With and Without Functional Ankle Instability: A Clinical Trial

Several studies have investigated gait biomechanics in people with functional ankle instability (FAI). However, the potential role of information processing (attention) in the gait control of these patients is still unknown. Therefore, this study aimed to investigate the effect of cognitive load on the range of motion (ROM) of lower limb joints during walking in men with and without FAI.

The study was a non-randomized controlled clinical trial. Eighteen male subjects with FAI and 19 healthy subjects participated in this study and completed three randomized conditions (three trials per condition): normal walking on a treadmill (single task), normal walking while performing a cognitive task (dual task), and (3) performing cognitive task while sitting. Three-dimensional information of hip, knee, and ankle joint ROM in the sagittal, frontal, and transverse planes were measured as gait kinematic components, and the error ratio and average reaction time were measured as cognitive task indicators. The intraclass correlation coefficient (ICC) was used to determine the intrasession reliability of kinematic and cognitive measures.

The ICC of kinematic variables, including the hip, knee, and ankle joint ROM, with and without applying cognitive tasks in three planes was more than 0.70. During the single task, the group with FAI showed a significantly decreased knee ROM in the transverse plane and a decreased hip ROM in the sagittal plane compared to the healthy group. During the dual task, the group with FAI showed a significantly increased hip ROM in the sagittal plane compared to the healthy group. The results of the cognitive task showed that the group with FAI had a longer reaction time in the auditory Stroop test during dual-task walking than in the sitting position.

FAI can be an important factor in motor-cognitive interactions. Using a cognitive task may be an effective strategy in the rehabilitation program of men with FAI.