<p>Demographic characteristics of the participants.</p>

This study investigates the impact of distal arch collapse on macroscopic gait parameters, static joint alignment, and dynamic kinematic deviation by integrating a dual-level analytical strategy at both the subject and individual limb levels.</p> <p>Methods</p><p>153 children with pediatric flexible flatfoot (25 unilateral, 128 bilateral) were included, and 3D gait data from 306 lower extremities were analyzed.

At the subject level, macroscopic spatiotemporal parameters were compared using the Mann-Whitney U test. At the limb level, linear mixed-effects models (LMMs) compared static 3D joint angles and Gait Variable Scores (GVS) between normal feet and flatfeet, treating subject as a random effect and adjusting for age, body mass index (BMI), and unilateral leg length.</p> <p>Results</p><p>At both the subject and limb levels, no significant between-group differences were observed in any core spatiotemporal parameters (e.g., Mean Velocity, Frequency, and Step Width) (P > 0.05).