踝关节稳定程度差异对冲击性变向动作中下肢肌肉协同模式的影响

关键词：功能性踝关节不稳  神经肌肉控制策略  肌肉协同  非负矩阵分解

Keywords:functional ankle instability  neuromuscular control strategies  muscle synergies  non-negative matrix decomposition

摘要：

      摘要 目的：分析功能性踝关节不稳（functional ankle instability， FAI）患者、踝关节扭伤后无不稳人群（Coper）及健康人群（control， CON）在跳跃落地侧切动作中的下肢肌肉协同模式。 方法：招募FAI、Coper和CON人群各12例（男女比例、损伤侧是否为利侧等指标均进行了组间匹配）。采集跳跃落地侧切动作中单侧下肢的运动学、动力学和表面肌电数据，使用非负矩阵分解算法对肌电数据进行协同分析，提取协同个数、方差解释率（variance accounted for， VAF）、协同结构、激活系数等参数。 结果：三组人群均存在四种协同模式。协同一主要激活伸髋肌和伸膝肌，在落地缓冲阶段发挥作用；协同二主要激活伸膝肌和踝跖屈肌，在落地缓冲和侧切发力阶段发挥作用；协同三主要激活膝屈肌和踝跖屈肌，在侧切发力阶段发挥作用；协同四主要激活胫前肌，在落地缓冲早期及侧切发力末期发挥作用，该协同的主要功能是维持踝关节稳定。三组协同个数无显著差异，但FAI组的VAF-1（协同个数为1所对应的VAF值）明显高于其他两组（P<0.05）。在协同结构中，FAI和Coper组表现出更大的髋膝周肌肉激活权重，更小的踝跖屈肌及外翻肌激活权重及更大的胫前肌激活权重（P<0.05）。在激活系数方面，Coper组会将协同二和协同三的激活峰值提前（P<0.05）。 结论：踝关节稳定程度差异并未改变下肢肌肉协同数量，但功能性踝关节不稳患者各协同结构内肌肉贡献度发生改变——产生了近端肌肉代偿性策略，足部肌肉侧重于维持踝关节矢状面的稳定，对缓冲及发力的功能性任务贡献减少；Coper人群通过中枢对激活系数的调整弥补了踝周肌肉激活的降低。

Abstract:

      Abstract Objective： To analyze the lower limb muscle synergy patterns during the jump landing/cutting in patients with functional ankle instability （FAI）， those who have experienced an ankle sprain without instability (Coper), and healthy controls (CON). Method： Twelve populations were recruited for each of the FAI， Coper， and CON groups （male/female ratio and whether the injured side was the favorable side were matched among groups）. Kinematic， kinetic and surface electromyography （sEMG） data were collected from the unilateral lower limb during the jumping landing/cutting maneuver. Muscle synergy analysis was conducted using a non-negative matrix decomposition algorithm to extract parameters including the number of synergies， variance accounted for （VAF）， synergy vectors， and activation coefficients. Result： Four synergy patterns existed in all three groups. Synergy 1 mainly activated the hip and knee extensors，contributing to impact absorption during landing. Synergy 2 mainly activated the knee extensors and ankle plantarflexors， functioning during both landing absorption and force generation in the lateral cut. Synergy 3 mainly activated the knee flexors and ankle plantarflexors， playing a role in the lateral cut force phase. Synergy 4 mainly activated the tibialis anterior muscle, contributing during the early landing phase and at the end of the lateral cut force generation phase, with a primary role in ankle stabilization. There was no significant difference in the number of synergies among the three groups， but the VAF-1（the VAF value when the number of synergy is 1） of FAI group was significantly higher than the other two groups（P<0.05）. In the synergy vectors， the FAI and Coper groups showed increased activation weights for the periprosthetic muscles， reduced activation weights for the ankle plantarflexors and extensor digitorum brevis， and greater activation weights for the tibialis anterior muscles（P<0.05）. In terms of activation coefficients， the Coper group exhibited an earlier peak activation of synergy 2 and synergy 3（P<0.05）. Conclusion： Differences in ankle stabilization did not affect the number of muscle synergies in the lower extremity， but muscle contributions within each synergy were altered in patients with FAI, indicating a compensatory strategy that relied more on proximal muscle while reducing the functional contributions of foot muscles to impact absorption and force generation. In the Coper group, reduced ankle muscle activation was compensated for by central adjustment of activation coefficient.