Tasks that require the cooperation of both hands and arms are common in human everyday life. Coordination helps to synchronize in space and temporally motion of the upper limbs. In fine bimanual tasks, coordination enables also to achieve higher degrees of precision that could be obtained from a single hand. We studied the acquisition of bimanual fine manipulation skills in watchmaking tasks, which require assembly of pieces at millimeter scale. It demands years of training. We contrasted motion kinematics performed by novice apprentices to those of professionals. Fifteen subjects, ten novices and five experts, participated in the study. We recorded force applied on the watch face and kinematics of fingers and arms. Results indicate that expert subjects wisely place their fingers on the tools to achieve higher dexterity. Compared to novices, experts also tend to align task-demanded force application with the optimal force transmission direction of the dominant arm. To understand the cognitive processes underpinning the different coordination patterns across experts and novice subjects, we followed the optimal control theoretical framework and hypothesize that the difference in task performances is caused by changes in the central nervous system’s optimal criteria. We formulated kinematic metrics to evaluate the coordination patterns and exploit inverse optimization approach to infer the optimal criteria. We interpret the human acquisition of novel coordination patterns as an alteration in the composition structure of the central nervous system’s optimal criteria accompanied by the learning process.

需要双手和手臂配合的任务在人类日常生活中很常见。协调有助于使上肢的空间和时间运动同步。在精细的双向任务中，协调还可以实现单手可以获得的更高的精度。我们研究了在制表任务中获取双手精细操作技能的技巧，这些技巧要求组装毫米级的零件。这需要多年的培训。我们将新手学徒与专业人员进行的运动运动学进行了对比。十五名受试者，十名新手和五名专家参加了研究。我们记录了作用在表盘上的力以及手指和手臂的运动学。结果表明，专家受试者明智地将手指放在工具上以获得更高的灵活性。与新手相比 专家们还倾向于将任务要求的力量应用与优势手臂的最佳力量传递方向保持一致。为了理解支持专家和新手之间不同协调模式的认知过程，我们遵循最佳控制理论框架，并假设任务绩效的差异是由中枢神经系统最佳标准的变化引起的。我们制定了运动学指标来评估协调模式，并利用逆向优化方法来推断最佳标准。我们将人类对新的协调模式的理解解释为伴随学习过程的中枢神经系统最佳标准组成结构的变化。