Equinus and toe walking are common locomotor disorders in children with cerebral palsy (CP) walking barefoot or with normal shoes. We hypothesized that, regardless of the type of footwear, the plantar flexors do not cause early equinus upon initial foot contact, but decelerate ankle dorsiflexion during weight acceptance (WA). This latter action promoted by early flat-foot contact is hypothesized to be functional. Hence, we performed an instrumented gait analysis of 12 children with CP (Gross Motor Function Classification System class: I or II; mean age: 7.2 years) and 11 age-matched typically developing children. The participants walked either barefoot, with unmodified footwear (4° positive-heel shoes) or with 10° negative-heel shoes (NHSs). In both groups, wearing NHSs was associated with greater ankle dorsiflexion upon initial foot contact, and greater tibialis anterior activity (but no difference in soleus activity) during the swing phase. However, the footwear condition did not influence the direction and amplitude of the first ankle movement during WA and the associated peak negative ankle power. Regardless of the footwear condition, the CP group displayed (i) early flattening of the foot and ample dorsiflexion (decelerated by the plantar flexors) during WA, and (ii) low tibialis anterior and soleus activities during the second half of the swing phase (contributing to passive equinus upon foot strike). In children with CP, the early action of plantar flexors (which typically decelerate the forward progression of the center of mass) may be a compensatory mechanism that contributes to the WA's role in controlling balance during gait.

中文翻译：

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脑瘫儿童的脚趾行走：足底屈肌可能的功能作用。

马蹄足和足趾行走是脑瘫 (CP) 儿童赤脚行走或穿普通鞋行走时常见的运动障碍。我们假设，无论鞋类的类型如何，足底屈肌在最初的足部接触时不会引起早期马蹄足，但会在承受重量 (WA) 期间使踝关节背屈减速。由早期平足接触促进的后一种动作被假设为是功能性的。因此，我们对 12 名 CP 儿童（粗大运动功能分类系统等级：I 或 II；平均年龄：7.2 岁）和 11 名年龄匹配的典型发育儿童进行了步态分析。参与者要么赤脚走路，穿着未经修改的鞋子（4° 正跟鞋）或穿着 10° 负跟鞋（NHS）。在两组中，首次接触足部时，佩戴 NHS 与更大的踝关节背屈相关，摆动阶段胫骨前肌活动度更高（但比目鱼肌活动度没有差异）。然而，鞋的状况不会影响 WA 期间第一次踝关节运动的方向和幅度以及相关的峰值负踝力量。无论鞋类状况如何，CP 组都表现出 (i) 在 WA 期间足部早期变平和充足的背屈（由足底屈肌减速），以及 (ii) 在摆动阶段的后半段胫骨前肌和比目鱼肌活动度较低（在足部撞击时导致被动马蹄足）。在患有 CP 的儿童中，足底屈肌的早期动作（通常会减慢重心的向前进展）可能是一种补偿机制，有助于 WA 在控制步态平衡方面的作用。