Foot placement strategy during walking in people with incomplete spinal cord injury

Impaired balance during walking is a common problem in people with incomplete spinal cord injury (iSCI). To improve walking capacity, it is crucial to characterize balance control and how it is affected in this population. The foot placement strategy, a dominant mechanism to maintain balance in the mediolateral (ML) direction during walking, can be affected in people with iSCI due to impaired sensorimotor control. This study aimed to determine if the ML foot placement strategy is impaired in people with iSCI compared to healthy controls.

This data collection includes data from individuals with iSCI (n = 28) and healthy controls (n = 19) who performed a two-minute walk test at a self-paced walking speed on an instrumented treadmill. Healthy controls performed one extra test at a fixed speed set at 50% of their preferred speed.

To study the foot placement strategy of a participant, linear regression was used to predict the ML foot placement based on the ML center of mass position and velocity. The accuracy of the foot placement strategy was evaluated by the root mean square error between the predicted and actual foot placements and was referred to as foot placement deviation. To confirm adherence to the foot placement strategy, the goodness of the fit of the linear regression model was evaluated with the coefficient of determination, here referred to as foot placement adherence. In addition, the within-subject standard deviation of actual foot placement was determined. Step width was selected as a secondary outcome measure.

行走时的平衡障碍是不完全性脊髓损伤（incomplete spinal cord injury, iSCI）患者的常见问题。为改善患者的行走能力，精准刻画该人群的平衡控制机制及其受损情况至关重要。足放置策略是行走过程中维持中外侧（mediolateral, ML）方向平衡的核心调控机制，而不完全性脊髓损伤（iSCI）患者因感觉运动控制受损，其足放置策略可能出现异常。本研究旨在探究与健康对照组相比，不完全性脊髓损伤（iSCI）患者的中外侧足放置策略是否存在受损情况。

本数据集收录了28名不完全性脊髓损伤（iSCI）患者与19名健康对照者的数据，所有受试者均在仪器化跑台上以自定步速完成了2分钟行走测试。健康对照者额外完成了一项固定速度测试，该速度设定为其偏好步速的50%。

为分析受试者的足放置策略，本研究采用线性回归模型，基于中外侧质心位置与速度预测中外侧足放置位置。足放置策略的准确性通过预测足放置位置与实际足放置位置间的均方根误差（root mean square error, RMSE）进行评估，该指标被称为足放置偏差。为验证受试者对足放置策略的依从性，本研究采用决定系数（coefficient of determination, R²）评估线性回归模型的拟合优度，该指标被称为足放置依从性。此外，本研究还计算了受试者实际足放置位置的组内标准差，并将步幅宽度选为次要结局指标。