Hu Xiaogang, Newell Karl M
Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA.
Motor Control. 2012 Jul;16(3):297-316. doi: 10.1123/mcj.16.3.297. Epub 2012 May 24.
This study investigated the asymmetry of bilateral interference in relation to the relative difference of force amplitude between hands and the hand dominance. In Experiment 1, one hand produced a fixed constant force of 5% maximum voluntary contraction (MVC) while the other hand produced different constant forces of 5%, 20%, and 50% MVC in blocked conditions. Asymmetric interference in force amplitude alone was evident in that the hand producing the fixed low force showed a stronger interference than the hand performing the higher force. Asymmetric interference in hand dominance was also found in that more interference was observed when the nondominant left hand produced the higher force, a finding that does not support the hemisphere specialization hypothesis. Experiment 2 was performed to rule out the fixed force level interpretation compared with the low force level account and the fixed force was set at 50% MVC. The results were consistent with the findings in Experiment 1 showing asymmetric interference with force amplitude rather than with fixed force level. The findings revealed that without a timing constraint the task demand associated with force amplitude alone can induce the asymmetric bilateral interference. The external task asymmetry and intrinsic asymmetry of the organism interact and influence the bimanual force coordination and control patterns.
本研究调查了双侧干扰的不对称性与双手力量幅度的相对差异以及手的优势之间的关系。在实验1中，一只手产生5%最大自主收缩（MVC）的固定恒定力，而另一只手在分块条件下产生5%、20%和50%MVC的不同恒定力。仅在力量幅度方面的不对称干扰是明显的，即产生固定低力量的手比执行较高力量的手表现出更强的干扰。在手的优势方面也发现了不对称干扰，即当非优势左手产生较高力量时观察到更多干扰，这一发现不支持半球特化假说。进行实验2以排除与低力量水平解释相比的固定力量水平解释，并将固定力量设定为50%MVC。结果与实验1的结果一致，显示出与力量幅度而非固定力量水平相关的不对称干扰。研究结果表明，在没有时间限制的情况下，仅与力量幅度相关的任务需求就可以诱发不对称的双侧干扰。机体的外部任务不对称性和内在不对称性相互作用并影响双手力量协调和控制模式。
