Changes in lower-extremity biomechanics in children with flexible flatfoot

XU Huanlan; LI Mingdi; ZHANG Hewei; CHEN Xiaoming; GU Qin; LIANG Guanjun

doi:10.11852/zgetbjzz2025-1412

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Chinese Journal of Child Health Care ›› 2026, Vol. 34 ›› Issue (10) : 1105-1110. DOI: 10.11852/zgetbjzz2025-1412

Early-life Prevention of Chronic Disease

Changes in lower-extremity biomechanics in children with flexible flatfoot

XU Huanlan¹, LI Mingdi¹, ZHANG Hewei¹, CHEN Xiaoming², GU Qin¹, LIANG Guanjun¹

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Abstract

Objective To investigate changes in gait spatiotemporal and kinematic parameters, plantar biomechanics, and lower-extremity electromyographic activity in children with flexible flatfoot, and to analyze potential compensatory manifestations associated with abnormal arch structure, so as to provide evidence for rehabilitation assessment and intervention. Methods From February 2024 to June 2025, 30 children with flexible flatfoot were recruited as observation group from the Department of Rehabilitation Medicine, Children's Hospital of Soochow University, meanwhile 30 children with normal feet matched by age and gender were selected as control group. A three-dimensional gait motion-capture and training system, a plantar-pressure testing system, and surface electromyography were used to compare gait spatiotemporal parameters, lower-extremity kinematic parameters, plantar biomechanical parameters, and lower-extremity muscle activity between the two groups. Results Compared with the control group, the observation group had a shorter stride length and lower gait speed (t=-2.740,-2.347, P<0.05), a smaller maximum ankle dorsiflexion angle (Z=-2.973,P<0.01), and maximum plantarflexion angle (t=-3.631, P<0.01); and a larger maximum knee-flexion angle (t=3.472,P<0.01). The medial and forefoot load ratios were higher (t=6.155, 2.552, P<0.05), whereas the lateral displacement of the center of pressure was lower (t=-2.469, P<0.05). The root mean square (RMS) values of the tibialis anterior and gastrocnemius muscles were also significantly higher (Z=5.025,4.582,P<0.01). Conclusions Children with flexible flatfoot exhibit abnormal arch structure, altered gait patterns, and compensatory activation of lower-extremity muscles, which may increase the long-term risk of sports injuries. Early biomechanical assessment and intervention should therefore be considered.

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flexible flatfoot / lower-extremity biomechanics / gait analysis / plantar pressure / children

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XU Huanlan, LI Mingdi, ZHANG Hewei, CHEN Xiaoming, GU Qin, LIANG Guanjun. Changes in lower-extremity biomechanics in children with flexible flatfoot[J]. Chinese Journal of Child Health Care. 2026, 34(10): 1105-1110 https://doi.org/10.11852/zgetbjzz2025-1412

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