Esteves José, Dinis Ricardo, Fernandes Orlando, Castro Maria António, Oliveira Raul, Pezarat-Correia Pedro
Escola Superior de Saúde do Alcoitão, Lisboa, Portugal; Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisboa, Portugal.
Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisboa, Portugal.
Phys Ther Sport. 2022 Jul;56:8-14. doi: 10.1016/j.ptsp.2022.05.014. Epub 2022 Jun 4.
Chronic ankle instability (CAI) is characterized by the occurrence of repetitive inversion mechanism of the ankle, resulting in numerous ankle sprains. CAI occurs in approximately 70% of patients with a history of a lateral ankle sprain. Many causes of functional ankle instability have been postulated and include deficits in proprioception, impaired neuromuscular-firing patterns, disturbed balance and postural control.
The purpose of this study was to compare postural control behaviour in subjects with chronic ankle instability and healthy subjects, using the traditional linear and nonlinear variables for the centre of pressure (CoP) displacement, during one-leg stance on stable and unstable surfaces.
16 CAI subjects and 20 healthy subjects were evaluated with the single leg stance on a stable surface and an unstable surface, for 60 s with a force plate. The traditional linear variables like CoP displacement, CoP amplitude and CoP velocity were calculated. Variability of CoP displacement was also submitted to nonlinear analysis and the approximated entropy, sample entropy, correlation dimension and Lyapunov exponent were calculated.
On the stable surface, no differences between groups for all the traditional variables were found but the correlation dimension of CoP mediolateral displacement had lower values on the CAI group with statistical significance (p < 0.05). On the unstable surface, no differences were found neither with linear variable neither with variability nonlinear analysis.
Correlated dimension of CoP displacement during one-leg stance on a stable surface was the only variable that show significant differences between the two groups. The lower values of this variable in the CAI subjects may implicate a balance control system with more difficulties to adapt to the environment and the task demands. More studies are needed to better understand CAI subjects balance control.
慢性踝关节不稳（CAI）的特征是踝关节反复出现内翻机制，导致多次踝关节扭伤。约70%有外侧踝关节扭伤病史的患者会出现CAI。人们推测了功能性踝关节不稳的多种原因，包括本体感觉缺陷、神经肌肉放电模式受损、平衡和姿势控制紊乱。
本研究的目的是比较慢性踝关节不稳受试者和健康受试者的姿势控制行为，在稳定和不稳定表面单腿站立期间，使用传统的线性和非线性变量来分析压力中心（CoP）位移。
16名CAI受试者和20名健康受试者在稳定表面和不稳定表面上进行单腿站立评估，使用测力板持续60秒。计算了传统的线性变量，如CoP位移、CoP幅度和CoP速度。CoP位移的变异性也进行了非线性分析，并计算了近似熵、样本熵、关联维数和李雅普诺夫指数。
在稳定表面上，两组在所有传统变量上均未发现差异，但CAI组CoP中外侧位移的关联维数较低，具有统计学意义（p<0.05）。在不稳定表面上，线性变量和变异性非线性分析均未发现差异。
在稳定表面上单腿站立期间CoP位移的关联维数是两组之间唯一显示出显著差异的变量。CAI受试者中该变量的较低值可能意味着平衡控制系统更难适应环境和任务需求。需要更多研究来更好地理解CAI受试者的平衡控制。
