Centre for Sensorimotor Neuroscience, School of Human Movement Studies, The University of Queensland, Brisbane, Australia.
Exp Brain Res. 2011 Aug;213(1):117-24. doi: 10.1007/s00221-011-2781-1. Epub 2011 Jul 7.
Although rhythmic coordination has been extensively studied in the literature, questions remain about the correspondence of constraints that have been identified in the related contexts of inter-limb and intra-limb coordination. Here we used a 2-DOF robot arm which allows flexible manipulation of forces to investigate the effect on coordination stability of intra-limb coordination of: (i) the synchrony of force requirements and (ii) the involvement of bi-functional muscles. Ten subjects produced simultaneous rhythmic flexion-extension (FE) and supination-pronation (SP) elbow movements in two coordination patterns: (1) flexion synchronized with supination/extension with pronation (in-phase pattern) and (2) flexion synchronized with pronation/extension with supination (anti-phase pattern). The movements were produced with five different settings of the robot arm: a neutral setting that imposed balanced force requirements, and four other settings that increased the force requirements for one direction in both DOF. When combined with specific coordination patterns, these settings created conditions in which either synchronous or alternate patterns of forcing were necessary to perform the task. Results showed that synchronous tasks were more stable than asynchronous tasks (P < 0.05). Within the synchronous tasks, some robot settings were designed to either increase or decrease the use of bi-functional muscles. Although there was no difference for the bi-functional muscle biceps brachii, the coordination was more stable for the condition in which the greatest force requirements corresponded to the mechanical action of the bi-functional pronator teres (P < 0.05). In conclusion, force synchrony increases the stability of rhythmic intra-limb coordination, but further research is needed to clarify the role of bi-functional muscles in this effect.
尽管节奏协调在文献中已经得到了广泛的研究，但在肢体间和肢体内协调的相关背景下，对于已经确定的约束条件的对应关系仍存在一些问题。在这里，我们使用了一个 2-DOF 机器人手臂，它可以灵活地控制力，以研究以下因素对协调稳定性的影响：（i）力需求的同步性，以及（ii）双功能肌肉的参与。10 名受试者在两种协调模式下产生同步的屈/伸（FE）和旋前/旋后（SP）肘部运动：（1）屈肌与旋前/伸肌与旋后同步（同相模式），以及（2）屈肌与旋后/伸肌与旋前同步（反相模式）。运动是在机器人手臂的五个不同设置下产生的：一个中性设置，施加平衡的力需求，以及另外四个设置，在两个 DOF 中都增加了一个方向的力需求。当与特定的协调模式结合使用时，这些设置创造了需要同步或交替的强制模式来完成任务的条件。结果表明，同步任务比异步任务更稳定（P<0.05）。在同步任务中，一些机器人设置被设计为增加或减少双功能肌肉的使用。尽管对于双功能肌肉肱二头肌没有差异，但当最大力需求与双功能旋前肌的机械作用相对应时，协调更稳定（P<0.05）。总之，力同步增加了肢体内节奏协调的稳定性，但需要进一步研究以澄清双功能肌肉在这种效应中的作用。
