Broscheid Kim-Charline, Dettmers Christian, Vieten Manfred
Sportwissenschaften, Universität Konstanz, Germany.
Lurija Institute, Kliniken Schmieder Allensbach, Germany; Kliniken Schmieder Konstanz, Germany.
Gait Posture. 2018 Jun;63:242-247. doi: 10.1016/j.gaitpost.2018.05.015. Epub 2018 May 26.
Common methods of gait analyses measure step length/width, gait velocity and gait variability to name just a few. Those parameters tend to be changing with fitness and skill of the subjects. But, do stable subject characteristic parameters in walking exist? Does the Limit-Cycle-Attractor qualify as such a parameter?.
The attractor method is a new approach focusing on the dynamics of human motion. It classifies the fundamental walking pattern by calculating the Limit-Cycle-Attractor and its variability from acceleration data of the feet. Our hypothesis is that the fundamental walking pattern in healthy controls and in people with Multiple Sclerosis (pwMS) is stable, but can be altered through acute interventions or rehabilitation.
For this purpose, two investigations were conducted involving 113 subjects. The short-term stability was tested pre and post a 15 min passive/active MOTOmed (ergometer) session as well as up to 20 min afterwards. The long-term stability was tested over five weeks of rehabilitation once a week in pwMS. The main parameter of interest describes the velocity normalized average difference between two attractors (δM), which is an indicator for the change in movement pattern.
The Friedman's two-way ANOVA by ranks did not reveal any significant difference in δM. However, the conventional walking tests (6 min.10 m) improved significantly (p < 0.05) during rehabilitation. Contrary to our original hypothesis, the fundamental walking pattern was highly stable against controlled motor-assisted movement initiation via MOTOmed and rehabilitation treatment. Movement characteristics appeared to be independent of the improved fitness as indicated by the enhanced walking speed and distance.
The individual Limit-Cycle-Attractor is extremely robust and might indeed qualify as an (almost) invariable characteristic in human walking. This opens up the possibility to encode the individual walking characteristics. Conditions as Parkinson, Multiple Sclerosis etc., might display disease specific distinctions via the Limit-Cycle-Attractor.
步态分析的常用方法包括测量步长/步宽、步态速度和步态变异性等。这些参数往往会随着受试者的健康状况和技能而变化。但是，行走过程中是否存在稳定的受试者特征参数呢？极限环吸引子是否符合这样一个参数呢？
吸引子方法是一种关注人体运动动力学的新方法。它通过计算极限环吸引子及其从足部加速度数据得出的变异性来对基本行走模式进行分类。我们的假设是，健康对照者和多发性硬化症患者（pwMS）的基本行走模式是稳定的，但可通过急性干预或康复治疗而改变。
为此，进行了两项涉及113名受试者的研究。在15分钟的被动/主动MOTOmed（测力计）训练前后以及之后长达20分钟的时间内测试短期稳定性。在pwMS患者中，每周测试一次，持续五周的康复过程中的长期稳定性。主要关注参数描述了两个吸引子之间的速度归一化平均差异（δM），它是运动模式变化的一个指标。
弗里德曼双向秩方差分析未显示δM有任何显著差异。然而，在康复过程中，传统行走测试（6分钟10米）有显著改善（p<0.05）。与我们最初的假设相反，基本行走模式对通过MOTOmed和康复治疗进行的受控运动辅助启动具有高度稳定性。运动特征似乎与提高的健康状况无关，这表现为步行速度和距离的增加。
个体极限环吸引子极其稳健，可能确实可作为人类行走中（几乎）不变的特征。这为编码个体行走特征开辟了可能性。帕金森病、多发性硬化症等疾病可能通过极限环吸引子表现出疾病特异性差异。
