Development of human precision grip I: Basic coordination of force
Development of human precision grip I: Basic coordination of force
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人体精准握力发展一：力的基本协调
DOI：
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发表时间：
2004
影响因子：
2
通讯作者：
G. Westling
中科院分区：
文献类型：
--
作者：
H. Forssberg;A. Eliasson;H. Kinoshita;R. Johansson;G. Westling
摘要当儿童和成人在拇指和食指之间反复举起一个小物体时，研究人员检查了操纵力的协调性。连续测量握力、负载力(垂直提升力)、握力比和测试对象的垂直位置。在成人中，力量的产生是高度自动化的，并且在试验之间几乎是不变的。在建立夹点的预加载阶段之后，夹点和负载力在等距条件下平行增加，直到负载力克服重力，物体开始移动。在加载阶段，力的速率曲线基本上是钟形和单峰的，这表明力的增加是作为一个协调事件来编程的。两岁以下的儿童表现出一个较长的预加载阶段和一个加载阶段，在此期间握力和负载力不会同时增加。在加载力增加之前，握力会显著增加，在加载阶段开始时，握力通常是几个牛顿(N)。力率曲线是多峰的，随着力的逐步增加，最有可能的是允许外围反馈在力的控制中发挥重要作用。在两岁以后，握力在预负荷阶段增加较少。加载阶段更有规律地表现为握力和负载力平行增加，各个阶段的持续时间减少。年龄较大的儿童在一个力量速率脉冲中对力量进行编程，这表明出现了一种预期的策略。然而，直到几年后，成熟的力量协调才完全发展起来。结果表明，精密抓地力的发展是建立在升力协同耦合抓地力和负载力产生电路的基础上的，它似乎涉及从反馈控制到前馈控制的过渡。
SummaryThe coordination of manipulative forces was examined while children and adults repeatedly lifted a small object between the thumb and index finger. Grip force, load force (vertical lifting force), grip force rate and the vertical position of the test object were continuously measured. In adults, the force generation was highly automatized and was nearly invariant between trials. After a preload phase in which the grip was established, the grip and load forces increased in parallel under isometric conditions until the load force overcame the force of gravity and the object started to move. During this loading phase, the force rate profiles were essentially bell shaped and single peaked, suggesting that the force increases were programmed as one coordinated event. Children below the age of two exhibited a prolonged preload phase and a loading phase during which the grip and load forces did not increase in parallel. A major increase in grip force preceded the increase in load force, and at the start of the loading phase, the grip force was usually several Newtons (N). The force rate profiles were multi peaked with step-wise force increases most likely allowing peripheral feedback to play an important role in the control of the forces. After the age of two, the grip force increased less during the preload phase. The loading phase was more regularly characterized by a parallel increase of the grip force and load force and the duration of the various phases decreased. The older children programmed the forces in one force rate pulse indicating the emergence of an anticipatory strategy. Yet, the mature coordination of forces was not fully developed until several years later. It was concluded that the development of the precision grip was based upon the formation of a lift synergy coupling grip and load force generating circuits and that it seems to involve a transition from feedback control to feedforward control.