3D Gait Network Analysis of Ground Reaction Forces: A Case Study of Lower Limb Disorders and Walking Speeds

Previous research has indicated that human gait can be quantified using three-dimensional signals, each of which corresponds to distinct locomotor modules. However, no study has thoroughly investigated their interactions and the combined influence they exert on gait in a holistic way.

Three-dimensional ground reaction force (GRF) signals were recorded from 2,295 participants, including 211 healthy individuals and 2,084 patients with lower limb disorders- specifically those affecting the calcaneus, hip joint, knee joint, and ankle joint-for illustrative purposes. First, each dimensional GRF signal was decomposed into three distinct components: high frequency, medium-frequency, and low-frequency components. Subsequently, a gait network integrating these three frequency components of GRF signals across all three spatial dimensions was constructed.

Disease and walking speed both reshape the topology of gait networks. Lower-limb disorders reduce the importance of anterior-posterior nodes by 3.5% and increase that of medio-lateral nodes by 3.7%, while uniformly decreasing the gait network's edge weight, global efficiency, link strength, and modularity by approximately 4-5% (p < 0.01). In healthy adults, faster walking selectively enhances the importance of anterior posterior nodes by 4.2% and reduces that of vertical nodes by 3.2%. It leaves the gait network's edge weight, global efficiency, and link strength unchanged but increases its modularity by 8.8% (p < 0.001).

Traditionally, medicine and kinesiology have studied the human body by segmenting it into three independent dimensions. However, researching these dimensions in isolation is insufficient. Instead, it is imperative to establish interdisciplinary research networks and conceptualize human movement as a cohesive, integrated system.

Our research transcends conventional gait analysis: it facilitates the discovery of novel mechanisms underlying human movement and holds substantial potential for broad applications across multiple fields.