Department of Sport Science, University of Freiburg, Sandfangweg 4, 79102, Freiburg i. Br, Germany.
Department of Orthopedics and Trauma Surgery, Medical Faculty, University Medical Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
J Foot Ankle Res. 2021 Feb 17;14(1):13. doi: 10.1186/s13047-021-00452-0.
The application of ankle braces is an effective method for the prevention of recurrent ankle sprains. It has been proposed that the reduction of injury rates is based on the mechanical stiffness of the brace and on beneficial effects on proprioception and neuromuscular activation. Yet, how the neuromuscular system responds to the application of various types of ankle braces during highly dynamic injury-relevant movements is not well understood. Enhanced stability of the ankle joint seems especially important for people with chronic ankle instability. We therefore aimed to analyse the effects of a soft and a semi-rigid ankle brace on the execution of highly dynamic 180° turning movements in participants with and without chronic ankle instability.
Fifteen participants with functional ankle instability, 15 participants with functional and mechanical ankle instability and 15 healthy controls performed 180° turning movements in reaction to light signals in a cross-sectional descriptive laboratory study. Ankle joint kinematics and kinetics as well as neuromuscular activation of muscles surrounding the ankle joint were determined. Two-way repeated measures analyses of variance and post-hoc t-tests were calculated.
Maximum ankle inversion angles and velocities were significantly reduced with the semi-rigid brace in comparison to the conditions without a brace and with the soft brace (p ≤ 0.006, d ≥ 0.303). Effect sizes of these reductions were larger in participants with chronic ankle instability than in healthy controls. Furthermore, peroneal activation levels decreased significantly with the semi-rigid brace in the 100 ms before and after ground contact. No statistically significant brace by group effects were found.
Based on these findings, we argue that people with ankle instability in particular seem to benefit from a semi-rigid ankle brace, which allows them to keep ankle inversion angles in a range that is comparable to values of healthy people. Lower ankle inversion angles and velocities with a semi-rigid brace may explain reduced injury incidences with brace application. The lack of effect of the soft brace indicates that the primary mechanism behind the reduction of inversion angles and velocities is the mechanical resistance of the brace in the frontal plane.
应用踝部支具是预防复发性踝关节扭伤的有效方法。据推测，降低损伤率的原因是支具的机械刚度以及对本体感觉和神经肌肉激活的有益影响。然而，在高度动态的与损伤相关的运动中，各种类型的踝部支具如何影响神经肌肉系统尚不清楚。踝关节的稳定性增强对于慢性踝关节不稳定的患者尤其重要。因此，我们旨在分析软式和半刚性踝部支具在有和无慢性踝关节不稳定的参与者执行高度动态 180°转弯运动时的影响。
在一项横断面描述性实验室研究中，15 名功能性踝关节不稳定患者、15 名功能性和机械性踝关节不稳定患者和 15 名健康对照者在接收到光信号后进行 180°转弯运动。踝关节运动学和动力学以及踝关节周围肌肉的神经肌肉激活情况均被确定。使用双向重复测量方差分析和事后 t 检验进行计算。
与无支具和软支具的情况相比，半刚性支具显著降低了最大踝关节内翻角度和速度（p≤0.006，d≥0.303）。与健康对照组相比，慢性踝关节不稳定患者的这些降低的效应大小更大。此外，在接地前后的 100 毫秒内，半刚性支具使腓骨肌的激活水平显著降低。未发现支具与组之间存在统计学显著的影响。
基于这些发现，我们认为，特别是踝关节不稳定的患者似乎受益于半刚性踝部支具，因为这可以使他们将踝关节内翻角度保持在与健康人相似的范围内。半刚性支具可降低踝关节内翻角度和速度，这可能解释了应用支具可降低损伤发生率的原因。软支具没有效果表明，降低内翻角度和速度的主要机制是支具在额状面的机械阻力。
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