Background

Descending command in hemiparesis is reduced to agonists and misdirected to antagonists. We monitored agonist and antagonist activation along the swing phase of gait, comparing paretic and non-paretic legs.

Methods

Forty-two adults with chronic hemiparesis underwent gait analysis with bilateral EMG from tibialis anterior, soleus and gastrocnemius medialis. We monitored ankle and knee positions, and coefficients of agonist activation in tibialis anterior and of antagonist activation in soleus and gastrocnemius medialis over the three thirds of swing phase. These coefficients were defined as the ratio of the root-mean-square EMG from one muscle over any period to the root-mean-square EMG from the same muscle over 100 ms of its maximal voluntary isometric contraction.

Findings

As against the non-paretic side, the paretic side showed lesser ankle dorsiflexion and knee flexion (P < 1.E⁻⁵), with higher coefficients of agonist activation in tibialis anterior (+100 ± 28%, P < 0.05), and of antagonist activation in soleus (+224 ± 41%, P < 0.05) and gastrocnemius medialis (+276 ± 49%, P < 0.05). On the paretic side, coefficient of agonist activation in tibialis anterior decreased from mid-swing on; coefficients of antagonist activation in soleus and gastrocnemius medialis increased and ankle dorsiflexion decreased in late swing (P < 0.05).

Interpretation

During the swing phase in hemiparesis, normalized tibialis anterior recruitment is higher on the paretic than on the non-paretic leg, failing to compensate for a marked increase in plantar flexor activation (cocontraction). The situation deteriorates along swing with a decrease in tibialis anterior recruitment in parallel with an increase in plantar flexor activation, both likely related to gastrocnemius stretch during knee re-extension.

Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT03119948

中文翻译：

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沿偏瘫步态的摆动期监测踝部的激动剂和拮抗剂激活

背景

偏瘫中的下降指令被简化为激动剂并被误导为拮抗剂。我们沿着步态的摆动阶段监测激动剂和拮抗剂的激活，比较麻痹和非麻痹腿。

方法

42 名患有慢性偏瘫的成年人接受了来自胫骨前肌、比目鱼肌和腓肠肌内侧肌的双侧 EMG 的步态分析。我们监测了踝关节和膝关节的位置，以及在三分之三的摆动期中胫骨前肌的激动剂激活系数和比目鱼肌和腓肠肌内侧肌的拮抗剂激活系数。这些系数被定义为任何时期的一块肌肉的均方根 EMG 与同一肌肉在其最大自主等长收缩 100 毫秒内的均方根 EMG 的比率。

发现

与非麻痹侧相比，麻痹侧的踝关节背屈和膝关节屈曲较小（P  < 1.E ^-5），胫骨前肌的激动剂激活系数较高（+100 ± 28%，P  < 0.05），并且比目鱼肌 (+224 ± 41%, P  < 0.05) 和腓肠肌内侧 (+276 ± 49%, P  < 0.05) 的拮抗剂激活率。在麻痹侧，胫骨前肌的激动剂激活系数从摆动中期开始下降；摆动后期比目鱼肌和腓肠肌拮抗剂激活系数增加，踝背屈减少（P  < 0.05）。

解释

在偏瘫的摆动期，偏瘫腿的标准化胫骨前肌募集高于非偏瘫腿，无法补偿足底屈肌激活（共收缩）的显着增加。这种情况随着摆动而恶化，胫骨前部募集减少，同时跖屈肌激活增加，这两者都可能与膝关节重新伸展期间的腓肠肌拉伸有关。

临床试验注册-URL：http://www.clinicaltrials.gov。唯一标识符：NCT03119948