Abboud Jacques, Daneau Catherine, Nougarou François, Dugas Claude, Descarreaux Martin
Department of Anatomy, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada.
Department of Human Kinetics, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada.
J Neurophysiol. 2018 Oct 1;120(4):1591-1601. doi: 10.1152/jn.00207.2018. Epub 2018 Jul 5.
In complex anatomical systems, such as the trunk, motor control theories suggest that many motor solutions can be implemented to achieve a similar goal. Although reflex mechanisms act as a stabilizer of the spine, how the central nervous system uses trunk redundancy to adapt neuromuscular responses under the influence of external perturbations, such as experimental pain or spinal tissue creep, is still unclear. The aim of this study was to identify and characterize trunk neuromuscular adaptations in response to unexpected trunk perturbations under the influence of spinal tissue creep and experimental back pain. Healthy participants experienced a repetition of sudden external trunk perturbations in two protocols: 1) 15 perturbations before and after a spinal tissue creep protocol and 2) 15 perturbations with and without experimental back pain. Trunk neuromuscular adaptations were measured by using high-density electromyography to record erector spinae muscle activity recruitment patterns and a motion analysis system. Muscle activity reflex attenuation was found across unexpected trunk perturbation trials under the influence of creep and pain. A similar area of muscle activity distribution was observed with or without back pain as well as before and after creep. No change of trunk kinematics was observed. We conclude that although under normal circumstances muscle activity adaptation occurs throughout the same perturbations, a reset of the adaptation process is present when experiencing a new perturbation such as experimental pain or creep. However, participants are still able to attenuate reflex responses under these conditions by using variable recruitment patterns of back muscles. NEW & NOTEWORTHY The present study characterizes, for the first time, trunk motor adaptations with high-density surface electromyography when the spinal system is challenged by a series of unexpected perturbations. We propose that the central nervous system is able to adapt neuromuscular responses by using a variable recruitment pattern of back muscles to maximize the motor performance, even under the influence of pain or when the passive structures of the spine are altered.
在诸如躯干这样复杂的解剖系统中，运动控制理论表明，可以采用多种运动解决方案来实现相似的目标。尽管反射机制起到了脊柱稳定器的作用，但中枢神经系统如何利用躯干冗余在诸如实验性疼痛或脊柱组织蠕变等外部干扰的影响下调整神经肌肉反应，目前仍不清楚。本研究的目的是识别和描述在脊柱组织蠕变和实验性背痛影响下，躯干对意外躯干干扰的神经肌肉适应性。健康参与者在两个实验方案中经历了一系列突然的外部躯干干扰：1）在脊柱组织蠕变实验方案前后各进行15次干扰；2）在有和没有实验性背痛的情况下各进行15次干扰。通过使用高密度肌电图记录竖脊肌活动募集模式和运动分析系统来测量躯干神经肌肉适应性。发现在蠕变和疼痛影响下的意外躯干干扰试验中，肌肉活动反射减弱。无论有无背痛以及在蠕变前后，都观察到了相似的肌肉活动分布区域。未观察到躯干运动学的变化。我们得出结论，尽管在正常情况下，肌肉活动适应性在相同的干扰过程中都会发生，但当经历诸如实验性疼痛或蠕变等新的干扰时，适应性过程会重置。然而，参与者在这些条件下仍能够通过使用背部肌肉的可变募集模式来减弱反射反应。新内容与值得关注之处：本研究首次使用高密度表面肌电图对脊柱系统受到一系列意外干扰时的躯干运动适应性进行了描述。我们提出，即使在疼痛影响下或脊柱被动结构改变时，中枢神经系统也能够通过使用背部肌肉的可变募集模式来调整神经肌肉反应，以最大限度地提高运动表现。
