Bouffard Jason, Salomoni Sauro E, Mercier Catherine, Tucker Kylie, Roy Jean-Sébastien, van den Hoorn Wolbert, Hodges Paul W, Bouyer Laurent J
Department of Rehabilitation, Université Laval , Quebec City , Canada.
Center for Interdisciplinary Research in Rehabilitation and Social Integration, CIUSSS-CN Quebec City , Canada.
J Neurophysiol. 2018 May 1;119(5):1647-1657. doi: 10.1152/jn.00411.2017. Epub 2018 Jan 24.
As individuals with musculoskeletal disorders often experience motor impairments, contemporary rehabilitation relies heavily on the use of motor learning principles. However, motor impairments are often associated with pain. Although there is substantial evidence that muscle pain interferes with motor control, much less is known on its impact on motor learning. The objective of the present study was to assess the effects of muscle pain on locomotor learning. Two groups (Pain and Control) of healthy participants performed a locomotor adaptation task (robotized ankle-foot orthosis perturbing ankle movements during swing) on two consecutive days. On day 1 (acquisition), hypertonic saline was injected in the tibialis anterior (TA) muscle of the Pain group participants, while Control group participants were pain free. All participants were pain free on day 2 (retention). Changes in movement errors caused by the perturbation were assessed as an indicator of motor performance. Detailed analysis of kinematic and electromyographic data provided information about motor strategies. No between-group differences were observed on motor performance measured during the acquisition and retention phases. However, Pain group participants had a residual movement error later in the swing phase and smaller early TA activation than Control group participants, thereby suggesting a reduction in the use of anticipatory motor strategies to overcome the perturbation. Muscle pain did not interfere with global motor performance during locomotor adaptation. The different motor strategies used in the presence of muscle pain may reflect a diminished ability to anticipate the consequences of a perturbation. NEW & NOTEWORTHY This study shows that experimental muscle pain does not influence global motor performance during the acquisition or next-day retention phases of locomotor learning. This contrasts with previous results obtained with cutaneous pain, emphasizing the risk of directly extrapolating from one pain modality to another. Muscle pain affected motor strategies used when performing the task, however: it reduced the ability to use increased feedforward control to overcome the force field.
由于患有肌肉骨骼疾病的个体常伴有运动功能障碍，当代康复治疗严重依赖运动学习原则的运用。然而，运动功能障碍往往与疼痛相关。尽管有大量证据表明肌肉疼痛会干扰运动控制，但对于其对运动学习的影响却知之甚少。本研究的目的是评估肌肉疼痛对运动学习的影响。两组健康参与者（疼痛组和对照组）连续两天进行了一项运动适应任务（在摆动期使用机器人辅助踝足矫形器干扰踝关节运动）。在第1天（习得阶段），向疼痛组参与者的胫骨前肌注射高渗盐水，而对照组参与者无疼痛。在第2天（保持阶段），所有参与者均无疼痛。将由干扰引起的运动误差变化作为运动表现的指标进行评估。对运动学和肌电图数据的详细分析提供了有关运动策略的信息。在习得阶段和保持阶段测量的运动表现方面，未观察到组间差异。然而，疼痛组参与者在摆动期后期的残余运动误差比对照组参与者小，且早期胫骨前肌激活程度也较小，这表明在克服干扰时，预期运动策略的使用有所减少。肌肉疼痛在运动适应过程中并未干扰整体运动表现。在存在肌肉疼痛的情况下使用的不同运动策略可能反映出预测干扰后果的能力下降。新发现与值得关注之处 本研究表明，实验性肌肉疼痛在运动学习的习得阶段或次日保持阶段不会影响整体运动表现。这与先前关于皮肤疼痛的研究结果形成对比，强调了直接从一种疼痛模式推断到另一种疼痛模式的风险。然而，肌肉疼痛会影响执行任务时使用的运动策略：它降低了使用增强的前馈控制来克服力场的能力。
