Pinho Liliana, Freitas Marta, Pinho Francisco, Silva Sandra, Figueira Vânia, Ribeiro Edgar, Sousa Andreia S P, Sousa Filipa, Silva Augusta
Escola Superior de Saúde do Vale do Ave, Cooperativa de Ensino Superior Politécnico e Universitário, Rua José António Vidal, 81, 4760-409 Vila Nova de Famalicão, Portugal.
Centre of Research Rehabilitation (CIR), Escola Superior de Saúde, rua Dr. António Bernardino de Almeida 400, 4200-072 Porto, Portugal.
Sensors (Basel). 2025 Mar 30;25(7):2196. doi: 10.3390/s25072196.
To analyse the relationship between traditional stiffness and muscle antagonist coactivation in both stroke and healthy participants, using linear and non-linear measures of coactivation and COP during standing, stand-to-sit, and gait initiation.
Participants were evaluated through a cross-sectional design. Electromyography, isokinetic dynamometer, and force plate were used to calculate coactivation, intrinsic and functional stiffness, and COP displacement, with both linear and non-linear metrics. Spearman's correlations and Mann-Whitney tests were applied ( < 0.05).
Post-stroke participants showed higher contralesional intrinsic stiffness ( = 0.041) and higher functional stiffness ( = 0.047). Coactivation was higher on the ipsilesional side during standing ( = 0.012) and reduced on the contralesional side during standing and transitions ( < 0.01). Moderate correlations were found between intrinsic and functional stiffness ( = 0.030) and between coactivation and intrinsic stiffness (standing and stand-to-sit: = 0.048) and functional stiffness (gait initiation: = 0.045). COP displacement was reduced in post-stroke participants during standing ( < 0.001) and increased during gait initiation ( = 0.001). Post-stroke participants exhibited increased gastrocnemius/tibialis anterior coactivation during gait initiation ( = 0.038) and higher entropy and stability across tasks ( < 0.001).
Post-stroke participants showed higher contralesional intrinsic and functional stiffness, reduced coactivation in static tasks, and increased coactivation in dynamic tasks. COP and coactivation analyses revealed impaired stability and random control, highlighting the importance of multidimensional evaluations of postural tone.
通过在站立、坐立转换和步态起始过程中使用共激活和中心压力（COP）的线性和非线性测量方法，分析中风患者和健康参与者的传统僵硬程度与肌肉拮抗肌共激活之间的关系。
采用横断面设计对参与者进行评估。使用肌电图、等速测力计和测力台，通过线性和非线性指标计算共激活、固有和功能僵硬程度以及COP位移。应用斯皮尔曼相关性分析和曼-惠特尼检验（<0.05）。
中风后参与者对侧的固有僵硬程度更高（=0.041），功能僵硬程度也更高（=0.047）。站立时患侧的共激活程度更高（=0.012），而站立和转换过程中对侧的共激活程度降低（<0.01）。固有和功能僵硬程度之间存在中等相关性（=0.030），共激活与固有僵硬程度之间（站立和坐立转换：=0.048）以及与功能僵硬程度之间（步态起始：=0.045）也存在中等相关性。中风后参与者在站立时COP位移减小（<0.001），在步态起始时COP位移增加（=0.001）。中风后参与者在步态起始时腓肠肌/胫前肌的共激活增加（=0.038），并且在各项任务中的熵和稳定性更高（<0.001）。
中风后参与者对侧的固有和功能僵硬程度更高，静态任务中的共激活减少，动态任务中的共激活增加。COP和共激活分析揭示了稳定性受损和随机控制能力下降，突出了对姿势张力进行多维度评估的重要性。
