Non-local neuromuscular effects and mechanisms

我们的实验室已经开展了非局部（一个身体部位的压力影响另一个身体部位的表现）疲劳（交叉疲劳），灵活性和疼痛的影响的工作。我们最近发表的综述（Halperin等人，2015）显示，当测试下半身（主要是股四头肌）而不是上半身时，非局部肌肉疲劳（NLMF）效应更为显著。这种偏好可能反映了上半身和下半身神经网络的差异。有证据表明NLMF效应主要归因于神经机制，但也有生物化学、生物力学和心理因素影响结局，这些因素可能相互关联。在这一主题上仍有许多问题悬而未决。我们最近对一篇提交的论文进行了修订，该论文表明NLMF在青少年男性中更普遍，影响了上半身和下半身的力量，跳跃高度和平衡性能。对侧肢体的减少几乎与疲劳肢体一样大，强调了神经系统在男性青年疲劳中的重要作用。我们最近还发表了唯一一项针对青春期女孩的研究，显示NLMF效应在该组中不太明显（Reid et al. 2016）。没有研究比较对侧与同侧的非局部反应，这将有助于突出神经疲劳途径。这样的研究增强了我们对基本肌肉疲劳机制的理解。我们在柔韧性和疼痛方面的非局部变化可能是重要的发现，对于那些患有中风引起的局部收缩屈曲的人来说，或者如果刺激未受影响的身体部位可以最大限度地减少疼痛和训练计划中使用的练习顺序。鉴于疲劳具有非局部或交叉效应，我们刚刚发表的一篇文章表明，虽然接受条件反射训练的肌肉群可以经历激活后增强，但对侧肌肉会经历疲劳。这些发现突出了外周（肌肉）和（中枢）神经成分对一轮运动的特定和不同的反应。可能在非局部、非条件肌肉中引起神经肌肉增强，这将证明中枢抑制和兴奋作用的程度。考虑到这一主题的重要性和相关性，需要更多的研究来阐明生理机制，使用适当的方法的影响程度，并试图解释一些描述的混杂变量。

Our laboratory has undertaken work on non-local (stress on one body part affecting the performance of another body part) effects of fatigue (crossover fatigue), flexibility and pain. Our recently published review (Halperin et al. 2015) revealed that non-local muscle fatigue (NLMF) effects are more predominant when the lower body (primarily the quadriceps) rather than the upper body is tested. This preference may reflect differences in the neural network of the upper and lower body. There is evidence for NLMF effects to be attributed to primarily neurological mechanisms however there are biochemical, biomechanical and psychological factors also influencing the outcome and these are likely to be inter-related. There are many questions still outstanding on this topic. We have recently provided a revision to a submitted paper that shows that NLMF is more prevalent with adolescent males affecting upper and lower body strength, jump height and balance performance. The decreases in the contralateral limb were nearly as substantial as the fatigued limb emphasizing the important role of the nervous system with fatigue in male youth. We also recently published the only study with adolescent girls showing the NLMF effect was less apparent in this group (Reid et al. 2016). There are no investigations comparing contralateral to ipsilateral non-local responses, which would help highlight neural fatigue pathways. Such investigations enhance our understanding of basic muscle fatigue mechanisms. Our non-local changes in flexibility and pain may be important findings for those suffering from localized contraction flexures from strokes or if stimulation of unaffected body parts can minimize pain and the order of exercises used in training programs. Whereas fatigue has non-local or crossover effects, we have just published an article demonstrating that while a muscle group treated with a conditioning exercise can experience post-activation potentiation, the contralateral muscle experiences fatigue. These findings highlight the specific and differing responses of peripheral (muscle) and (central) neural components to a bout of exercise. It may be possible to elicit neuromuscular potentiation in non-local, non-conditioned muscles which would demonstrate the extent of central inhibitory and excitatory effects. Considering the importance and relevance of this topic, more research is needed to clarify the physiological mechanisms, extent of the effects using adequate methods, and with an attempt to account for some of the described confounding variables.