Experimental analysis of whole-body coordination changes associated with repetitive upper limb motion: what, when, why?

重复的动作经常是在日常生活中完成的。在工作场所，上肢重复的任务与肌肉骨骼疾病(MSD)有关，其中工作姿势和疲劳是一些最重要的风险因素。重复运动的一个重要方面是疲劳的潜在后果。疲劳对个体肌肉特征的短期影响是众所周知的。然而，很少有研究调查疲劳对全身的影响。此外，众所周知，上肢MSD在女性中的患病率更高，尽管原因尚不清楚。这项研究计划的总体目标是更好地了解健康人体上肢重复运动的生物力学和控制方面，以及在这些运动中所采用的姿势。在项目1中，我们将测量疲劳肌肉内以及全身肌肉之间发生的变化，以构建随着疲劳的发展整个身体发生变化的时间序列。在项目2中，受试者将执行各种任务(努力感、运动感、位置感)来评估疲劳对其本体感觉的影响。在项目3中，在重复任务中，躯干将被阻塞，同时记录疲劳时间和全身特征的变化。在所有项目中，我们还将评估男性和女性在疲劳反应模式上的潜在差异。这项研究的新颖性可以归因于提出的多水平实验方法，结合了对综合姿势和运动特征的空间和时间分析，用于研究肌肉模式和姿势-运动策略的变化的工具，以及试图确定男性和女性是否使用类似的策略来适应疲劳。作为一个整体，这个项目有可能有助于生物力学和运动控制的基本知识，与理解复杂的运动行为有关。这方面的知识反过来可作为使工作场所适应重复性工作的性别特点和制定工作培训制度以防止MSD的基础。

Repetitive motions are often accomplished during daily life. In the workplace, upper limb repetitive tasks have been linked with musculoskeletal disorders (MSD), of which working posture and fatigue account for some of the most important risk factors. An important aspect of repetitive movement is the potential consequence of fatigue. The short-term effects of fatigue on individual muscle characteristics are well known. However, few studies have investigated the effects of fatigue across the body. Also, it is well known that the prevalence of upper limb MSD is higher in women, although the reasons for this are unclear. The general objective of this research program is to gain a better understanding of the biomechanics and control aspects of upper limb repetitive movements, in relation to the posture adopted during these movements, in healthy humans. In project 1, we will measure changes occurring in within the fatigued muscle as well as between muscles across the body to construct a time sequence of changes occurring throughout the body as fatigue develops. In project 2, subjects will perform various tasks (effort sense, movement sense, position sense) to assess the effects of fatigue on their proprioception. In project 3, the trunk will be blocked during the repetitive task, while time to fatigue and changes in whole-body characteristics are recorded. In all projects, we will also assess potential differences in the fatigue response patterns between men and women. The novelty of this research program can be attributed to the proposed multi-level experimental approaches combining both spatial and temporal analyses of integrated posture and movement characteristics, the tools used to study changes in muscle patterns and posture-movement strategies and the attempt to determine if men and women use similar strategies to adapt to fatigue. As a whole, this program has the potential to contribute to fundamental knowledge of biomechanics and motor control related to the understanding of complex motor behavior. This knowledge may in turn serve as a basis to adapt the workplace to the gender-specific characteristics of repetitive work and to prescribe work training regimens to prevent the development of MSD.