Ghislieri Marco, Labanca Luciana, Mosca Massimiliano, Bragonzoni Laura, Knaflitz Marco, Benedetti Maria Grazia, Agostini Valentina
IEEE Trans Neural Syst Rehabil Eng. 2023;31:4367-4375. doi: 10.1109/TNSRE.2023.3328933. Epub 2023 Nov 8.
The aim of this study was to investigate balance performance and muscle synergies during a Single-Limb Stance (SLS) task in individuals with Chronic Ankle Instability (CAI) and a group of healthy controls. Twenty individuals with CAI and twenty healthy controls were asked to perform a 30-second SLS task in Open-Eyes (OE) and Closed-Eyes (CE) conditions while standing on a force platform with the injured or the dominant limb, respectively. The activation of 13 muscles of the lower limb, hip, and back was recorded by means of surface electromyography. Balance performance was assessed by identifying the number and the duration of SLS epochs, and the Root-Mean-Square (RMS) in Antero-Posterior (AP) and Medio-Lateral (ML) directions of the body-weight normalized ground reaction forces. The optimal number of synergies, weight vectors, and activation coefficients were also analyzed. CAI group showed a higher number and a shorter duration of SLS epochs and augmented ground reaction force RMS in both AP and ML directions compared to controls. Both groups showed an increase in the RMS in AP and ML forces in CE compared to OE. Both groups showed 4 optimal synergies in CE, while controls showed 5 synergies in OE. CAI showed a significantly higher weight of knee flexor muscles in both OE and CE. In conclusion, muscle synergies analysis provided an in-depth knowledge of motor control mechanisms in CAI individuals. They showed worse balance performance, a lower number of muscle synergies in a CE condition and abnormal knee flexor muscle activation compared to healthy controls.
本研究的目的是调查慢性踝关节不稳（CAI）患者和一组健康对照者在单腿站立（SLS）任务期间的平衡能力和肌肉协同作用。20名CAI患者和20名健康对照者分别被要求在睁眼（OE）和闭眼（CE）条件下，用受伤或优势腿站在测力平台上执行30秒的SLS任务。通过表面肌电图记录下肢、髋部和背部13块肌肉的激活情况。通过确定SLS时段的数量和持续时间，以及体重标准化地面反作用力在前后（AP）和内外侧（ML）方向上的均方根（RMS）来评估平衡能力。还分析了协同作用的最佳数量、权重向量和激活系数。与对照组相比，CAI组的SLS时段数量更多、持续时间更短，并且在AP和ML方向上的地面反作用力RMS均增加。与OE相比，两组在CE时AP和ML力的RMS均增加。两组在CE时均显示4种最佳协同作用，而对照组在OE时显示5种协同作用。CAI组在OE和CE时的屈膝肌权重均显著更高。总之，肌肉协同作用分析为深入了解CAI患者的运动控制机制提供了依据。与健康对照者相比，他们表现出更差的平衡能力、在CE条件下肌肉协同作用数量更少以及屈膝肌激活异常。
