Force coordination in static manipulation tasks: effects of the change in direction and handedness
Force coordination in static manipulation tasks: effects of the change in direction and handedness
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DOI：
10.1007/s00221-007-1064-3
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发表时间：
2007-12-01
影响因子：
2
通讯作者：
Jaric, Slobodan
中科院分区：
文献类型：
--
作者：
de Freitas, Paulo Barbosa;Krishnan, Vennila;Jaric, Slobodan
大量研究表明，在各种操作任务中，手握力（GF；作用于手指-物体接触区域的力的法向分量）和负载力（LF；切向分量）具有高度协调性。本研究的目的是探讨在双手操作任务中，LF 方向的变化以及惯用手对 GF 和 LF 协调的影响被主要忽视的影响。受试者 (N = 14) 在试验中对外部固定手柄施加双手正弦 LF 模式，逐渐从单向（仅在一个方向上施加 LF）变为完全双向（两个相反方向上的相同 LF 峰值）。尽管 LF 逐渐发生变化，但单向试验表现出较高的力量协调指数，而在所有双向试验中，无论 LF 在相反方向上的作用有多低和短暂，所有 GF 和 LF 协调指数都会恶化到相当低的水平。非惯用手表现出比惯用手更高的 LF 方向精度和更高的 GF 调制。我们得出的结论是，以单个和两个交替方向执行的操作任务可能基于部分独特的神经控制机制，并且双向任务所需的肌肉协同作用的切换可能在观察到的现象中发挥作用。关于手优势的影响，记录的非优势手的优势可以被认为是对当前非优势手臂/半球专门化控制肢体位置的观点的补充。
A number of studies have demonstrated high coordination of the hand grip force (GF; normal component of force acting at the digits-object contact area) and load force (LF; tangential component) in a variety of manipulation tasks. The aim of the study was to explore the mainly neglected effect of the change in LF direction and the effect of handedness on GF and LF coordination in bimanual manipulation task. Subjects (N = 14) exerted a bimanual sinusoidal LF pattern against externally fixed handles in trials that gradually changed from unidirectional (LF exerted only in one direction) to fully bidirectional (equal LF peaks in two opposite directions). Despite the gradual change of LF, unidirectional trials demonstrated high indices of force coordination, while in all bidirectional trials, no matter how low and brief LF exertion was in the opposite direction, all indices of GF and LF coordination deteriorated to a considerably lower level. The non-dominant hand demonstrated both a higher directional accuracy of exerting LF and higher GF modulation than the dominant one. We concluded that manipulation tasks performed in a single and two alternating directions may be based on partly distinctive neural control mechanisms, as well as that a switching of muscle synergies required in bidirectional tasks could play a role in the observed phenomenon. Regarding the effect of hand dominance, the recorded advantage of the non-dominant hand could be considered as an addition to the current views of the non-dominant arm/hemisphere specialization in controlling limb position.