Department of Kinesiology, University of Georgia, Athens, GA, United States.
Department of Health Sciences and Kinesiology, Georgia Southern University, Statesboro, GA, United States.
Gait Posture. 2024 Oct;114:227-233. doi: 10.1016/j.gaitpost.2024.09.013. Epub 2024 Sep 23.
Recovery of postural stability after taking a step is necessary to maintain functional mobility. Although children with cerebral palsy (CP) are at an increased risk of falling, their ability to recover stability following a step is unknown.
This study aimed to validate a method to assess step recovery in children with unilateral CP and determine if recovery of postural stability differs between limbs and across phases of step recovery.
Children with unilateral CP and matched typically developing controls (5-11 y; n=20/group) stood still on force platforms (quiet stance) and completed a forward step with their more-affected limb. Step recovery was divided into dynamic and static phases using vertical ground reaction force. Postural stability was assessed using center of pressure (COP) sample entropy, distance, and velocity of the more-affected (stepping) and less-affected (trailing) limbs in the anteroposterior and mediolateral directions.
Vertical ground reaction force during the static phase of step recovery and during quiet stance were not different for either limb and were strongly related (intraclass correlations >0.97, p<0.001), indicating concurrent validity of the step recovery method. Children with CP exhibited impaired recovery of postural stability after stepping, with deficits most pronounced in the mediolateral direction during the dynamic phase in the stepping limb as exhibited by lower COP sample entropy and higher COP distance and velocity (Cohen's d (d) range = 1.46-2.19, all p < 0.001). Deficits were present in the anteroposterior and mediolateral directions in the trailing limb, but they were limited to COP sample entropy and distance and the magnitude of the group differences was less pronounced (d range = 0.35-1.34).
Step recovery is a valid method to detect deficits in postural stability in children with unilateral CP, and the dynamic phase may be a sensitive target for interventions.
迈出一步后恢复姿势稳定性对于维持功能性移动能力是必要的。尽管脑瘫（CP）患儿跌倒的风险增加，但他们在迈出一步后恢复稳定性的能力尚不清楚。
本研究旨在验证一种评估单侧 CP 儿童步距恢复能力的方法，并确定在步距恢复的不同阶段，双侧肢体的姿势稳定性是否存在差异。
患有单侧 CP 的儿童和匹配的典型发育对照组（5-11 岁；每组 20 名）在力平台上站立不动（静立），并用其患侧肢体完成向前跨步。使用垂直地面反作用力将步距恢复分为动态和静态阶段。使用压力中心（COP）样本熵、距离和速度评估姿势稳定性，方向为前后向和左右向，分别测量患侧（跨步）和健侧（跟随）肢体。
无论是哪一侧肢体，在步距恢复的静态阶段和静立阶段的垂直地面反作用力均无差异，且两者相关性很强（组内相关系数>0.97，p<0.001），表明该步距恢复方法具有同时效度。CP 患儿在跨步后，姿势稳定性的恢复能力受损，在跨步侧的动态阶段，尤其在左右向，COP 样本熵较低，COP 距离和速度较高，表明存在较大的缺陷（Cohen's d（d）范围=1.46-2.19，均 p<0.001）。在跟随侧，前后向和左右向也存在缺陷，但仅局限于 COP 样本熵和距离，且组间差异的程度较小（d 范围=0.35-1.34）。
步距恢复是一种评估单侧 CP 儿童姿势稳定性缺陷的有效方法，动态阶段可能是干预的敏感目标。
