Tassani Simone, Font-Llagunes Josep M, González Ballester Miguel Ángel, Noailly Jérôme
Universitat Pompeu Fabra, BCN MedTech, Barcelona, Spain.
Universitat Politècnica de Catalunya, Biomechanical Engineering Lab, Department of Mechanical Engineering and Biomedical Engineering Research Centre, Barcelona, Spain; Institut de Recerca Sant Joan de Déu, Biomedical Engineering, Esplugues de Llobregat, Spain.
Gait Posture. 2019 Feb;68:220-226. doi: 10.1016/j.gaitpost.2018.11.034. Epub 2018 Nov 28.
Muscular co-contraction is a strategy commonly used by elders with the aim to increase stability. However, co-contraction leads to stiffness which in turns reduces stability. Some literature seems to suggest an opposite approach and to point out relaxation as a way to improve stability. Teaching relaxation is therefore becoming the aim of many studies letting unclear whether tension or relaxation are the most effective muscular strategy to improve stability. Relaxation is a misleading concept in our society. It is often confused with rest, while it should be addressed during stressing tasks, where it should aim to reduce energetic costs and increase stability. The inability to relax can be related to sub-optimal neuro-motor control, which can lead to increased stresses.
The objective of the study is to investigate the effect of voluntary muscle contraction and relaxation over the stability of human standing posture, answering two specific research questions: (1) Does the muscular tension have an impact on stability of standing posture? (2) Could this impact be estimated by using a minimally invasive procedure?
By using a force plate, we analysed the displacement of the center of pressure of 30 volunteers during state of tension and relaxation in comparison with a control state, and with open and closed eyes.
We found that tension significantly reduced the stability of subjects (15 out of 16 parameters, p < 0.003).
Our results show that daily situations of stress can lead to decreased stability. Such a loss might actually increase the risk of chronic joint overload or fall. Finally, breathing has direct effect over the management of pain and stress, and the results reported here point out the need to explicitly explore the troubling fact that a large portion of population might not be able to properly breath.
肌肉共同收缩是老年人常用的一种旨在提高稳定性的策略。然而，共同收缩会导致僵硬，进而降低稳定性。一些文献似乎提出了相反的方法，并指出放松是提高稳定性的一种方式。因此，教授放松技巧正成为许多研究的目标，这使得人们不清楚紧张还是放松是提高稳定性最有效的肌肉策略。在我们的社会中，放松是一个容易引起误解的概念。它常常与休息相混淆，而实际上放松应该在有压力的任务中进行，其目的应该是降低能量消耗并提高稳定性。无法放松可能与神经运动控制欠佳有关，这可能会导致压力增加。
本研究的目的是调查随意肌肉收缩和放松对人体站立姿势稳定性的影响，回答两个具体的研究问题：（1）肌肉紧张对站立姿势的稳定性有影响吗？（2）能否通过一种微创程序来估计这种影响？
我们使用测力板，分析了30名志愿者在紧张和放松状态下与对照状态相比，以及睁眼和闭眼时压力中心的位移。
我们发现紧张显著降低了受试者的稳定性（16个参数中有15个，p < 0.003）。
我们的结果表明，日常的压力情况会导致稳定性下降。这种下降实际上可能会增加慢性关节超负荷或跌倒的风险。最后，呼吸对疼痛和压力的管理有直接影响，此处报告的结果指出有必要明确探讨一个令人不安的事实，即很大一部分人群可能无法正确呼吸。
