Task-dependent organization of pinch grip forces
Task-dependent organization of pinch grip forces
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DOI：
10.1007/s00221-007-0864-9
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发表时间：
2007-06-01
影响因子：
2
通讯作者：
Gruben, Kreg G.
中科院分区：
文献类型：
--
作者：
Moerchen, Victoria A.;Lazarus, JoAnne C.;Gruben, Kreg G.
拇指和食指的力量在捏形成的组织进行了研究的条件下，指间力耦合的动力学约束被删除。两个视觉引导等距力任务在次最大水平被用来表征的空间和时间方面的手指间的力耦合。任务1提供了一个初步的表征手指间的力量协调时，手指之间的力量关系没有指定。任务2探讨在何种程度上，拇指和食指的首选协调可以解耦，无论是时间上和相对于力的大小，指定的手指之间的协调力。使用夹捏装置测量手指力，该夹捏装置被仪器化以独立地记录拇指（F-t）和食指（F-i）力的大小和方向。两个设备条件允许进一步检查手指间的力量协调时，手指之间的关系的力量是机械约束（枢轴条件），当手指之间的关系的力量不受约束，允许神经运动系统选择一个首选的模式，手指间的协调（固定条件）。16名右撇子成年人对该装置施加了一个捏力，以匹配一个单周期正弦波，该正弦波在每个参与者最大自愿捏力的15%和35%之间变化。目标呈现为正或负目标感觉，以改变试验中力水平的顺序和力变化的方向。当机械约束允许选择首选协调模式时，F-t = F-i是一个稳健的结果。相比之下，当手指力之间的协调被指定为同时产生和控制独立的拇指和食指的力量，同时作用于一个稳定的物体，受试者能够产生的力量，显着偏离F-t = F-i协调。捏的组织的特征在于手指力的优选的紧密耦合，其可以基于任务需求进行修改。
The organization of thumb and index finger forces in a pinch formation was investigated under conditions where kinetic constraints on interdigit force coupling were removed. Two visually guided isometric force tasks at submaximal levels were used to characterize the spatial and temporal aspects of interdigit force coupling. Task 1 provided an initial characterization of interdigit force coordination when the force relationship between the digits was not specified. Task 2 probed the extent to which a preferred coordination of the thumb and index finger could be decoupled, both temporally and with respect to force magnitude, by specifying the coordination between the digit forces. Digit forces were measured using a pinch apparatus that was instrumented to record the magnitude and direction of the thumb (F-t) and index finger (F-i) forces, independently. Two apparatus conditions allowed further examination of interdigit force coordination when the relationship between digit forces was mechanically constrained (pivot condition), and when the relationship between digit forces was not constrained, allowing the neuromotor system to select a preferred pattern of interdigit coordination (fixed condition). Sixteen right-handed adults exerted a pinch force against the apparatus to match a single-cycle sine wave that varied between 15 and 35% of each participant's maximal voluntary pinch force. The target was presented with positive or negative target sense, to vary the order of force level and direction of force change across the trials. When the mechanical constraints allowed selection of a preferred coordination pattern, F-t = F-i was a robust result. In contrast, when the coordination between the digit forces was specified by the requirement to simultaneously produce and control independent thumb and index finger forces while acting on a stable object, subjects were able to produce forces that markedly deviated from the F-t = F-i coordination. The organization of pinch is characterized by a preferred, tight coupling of digit forces, which can be modified based on task demands.