The effect of short-term walking on an artificially uneven surface on gait biomechanics: a 2D video analysis study

Background: Walking on uneven surfaces is a natural biomechanical challenge that stimulates neuromuscular adaptation, activates sensorimotor mechanisms and has rehabilitation applications. Despite growing interest in assessing adaptive responses, the effect of short-term exposure to uneven surfaces on gait parameters in healthy individuals remains understudied. Objective: To evaluate the immediate effect of short-term walking on an artificially uneven surface (step platforms) on gait biomechanics using a 2D video analysis. Materials and methods: Thirty-nine healthy volunteers (mean age: 29 years, height: 175 cm, weight: 78 kg) participated in the study and were randomly assigned to the main (n = 19) and control (n = 20) groups. All participants performed three stages of barefoot walking: (1) on a flat surface (baseline), (2) the main group – on an artificially uneven surface (step platforms), the control group – on a flat surface, (3) repeated walking on a flat surface. The biomechanical parameters (hip, knee, and ankle joint angles, step length, step time, speed) were assessed using a 2D video analysis (OpenPose, 240 fps). Statistical analysis was performed in StatTech v.4.8.5 code (Russia) using the Mann–Whitney U test (p<0,05). Results: Statistically significant differences in dominant frequency variance were observed in the main group at stages 2 and 3 (p < 0,001 and p = 0,002, respectively) compared to the control one. The main group showed an increase in the ankle dorsiflexion amplitude, knee flexion angle, step time and variability of movements after uneven surface walking which indicates the activation of sensorimotor adaptation mechanisms and the enhanced stability. Conclusion: Short-term walking on an artificially uneven surface induces immediate biomechanical adaptations which confirm diagnostic and rehabilitation potential of this type of exercise and the high sensitivity of a 2D video analysis for assessing adaptations.