Fatigue when learning motor skills: When does it matter? Can it help?

无论是在运动中，在工作中，还是在康复过程中，发展运动技能都需要重复数百到数千个动作。这样的高强度训练往往会导致疲劳的发展。我们目前对疲劳和运动学习之间的相互作用的了解仍然有限。疲劳什么时候会阻碍运动学习？它什么时候能帮上忙？当一个人休息时，从疲劳中学到的运动技能会转移到测试条件下吗？我的研究计划的长期目标是了解疲劳和运动学习之间的相互作用。这些知识对于加拿大各地的教练和治疗师来说是必不可少的，以优化运动学习干预。在接下来的五年里，我将检验这一假设，即在训练中经历疲劳的人将学习运动适应策略，以补偿疲劳对感觉运动系统的影响。如果这些策略有助于在培训期间取得更好的表现，那么这些策略将会得到很大程度的发展。当个体休息时，这些策略对表现的影响将取决于任务的特点。我的第一个目标是评估在训练过程中对运动疲劳适应的惩罚是否会阻止它们的获得、保留和转移。对肩部疲劳最常见的运动适应之一是躯干运动的增加。一些作者认为，这些适应是有利的，而在其他情况下，它们可能是不受欢迎的。当受训者在疲劳的情况下学习新的运动技能时，这些运动适应能力会保留吗？教练和治疗师有没有可能调整训练条件，从而促进有益的适应，而不鼓励消极的适应？为了评估这一假设，参与者将接受训练，进行连续的肩部外展任务，并伴有或不伴有疲劳。对于一些参与者来说，躯干运动将有助于他们的表现，而对另一些参与者来说，它们会使任务变得更加困难。我的第二个目标是确定学习推动轮椅时所经历的疲劳是否会带来更好的推进技术。在轮椅推进过程中，训练计划提倡更多地参与躯干运动，专家用户也观察到了这一点，并与发生肩痛的风险较低有关。因此，在经历肩部疲劳的情况下学习推动轮椅可能会导致更好的推进技术的发展。然而，如果躯干运动受到限制，这种有利的效果将被抵消，因为这将阻止疲劳诱导的运动适应的使用。为了这个目标，健康的人将学习在经历肩部疲劳的情况下，在测功器上以最大速度推动轮椅。对于一些参与者，后备箱将被固定。在所有研究中，运动学和肌电数据将在技能获得、保持和转移过程中评估运动适应和表现。将使用对性别敏感的分析。

Whether it is in sports, at work or during rehabilitation, developing motor skills require the repetition of hundreds to thousands of movements. Such intensive training often leads to the development of fatigue. Our current understanding of the interactions between fatigue and motor learning remains limited. When does fatigue hinder motor learning? When can it help? Do motor skills learnt with fatigue transfer to testing conditions when an individual is rested? The long-term objective of my research program is to understand the interactions between fatigue and motor learning. Such knowledge is essential for coaches and therapists across Canada to optimize motor learning interventions. During the next five years, I will test the hypothesis that individuals experiencing fatigue during training will learn motor adaptation strategies to compensate for effects of fatigue on the sensorimotor system. These strategies will develop mostly if they contribute to a better performance during training. The impact of these strategies on performance when the individual is rested will depend on task characteristics. My first objective is to evaluate if penalising motor adaptations to fatigue during training will prevent their acquisition, retention and transfer. One of the most frequent motor adaptations to shoulder fatigue is an increase in trunk movements. Some authors believe that these adaptations are favourable while in other contexts they may be unwanted. Are these motor adaptations retained when a trainee learns new motor skills with fatigue? Is it possible for coaches and therapists to adjust training conditions so helpful adaptations are promoted while negative ones are discouraged? To evaluate this hypothesis, participants will train to a sequential shoulder abduction task with or without fatigue. For some participants, trunk movements will contribute to their performance while, for others, they will make the task more difficult. My second objective is to determine if fatigue experienced when learning to propel a wheelchair will lead to better propulsion techniques. During wheelchair propulsion, a greater involvement of trunk movements is advocated by training programs, is observed in expert users and is associated with a lower risk of developing shoulder pain. Learning to propel a wheelchair while experiencing shoulder fatigue may therefore lead to the development of better propulsion techniques. However, this favourable effect would be cancelled out if trunk movements are constraints as it would prevent the use of fatigue-induced motor adaptations. For this objective, healthy individuals will learn to propel a wheelchair at maximal speed on an ergometer while experiencing shoulder fatigue, or not. For some participants, trunk will be immobilised. In all studies, motor adaptations and performance will be evaluated with kinematic and electromyographic data during skill acquisition, retention and transfer. Sex sensitive analyses will be used.