Directional coordination of thumb and finger forces during precision pinch.
Directional coordination of thumb and finger forces during precision pinch.
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DOI：
10.1371/journal.pone.0079400
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Li ZM
中科院分区：
文献类型：
--
作者：
Li K;Nataraj R;Marquardt TL;Li ZM
人类的对生拇指使手能够灵巧地操纵物体，这需要协调良好的手指力矢量。本研究旨在探讨精确捏指过程中拇指与食指所产生的力向量的方向协调性。14名右撇子健康受试者被要求用拇指和食指的指腹对外部稳定装置施加捏力。受试者施加力以遵循力斜坡曲线，该力斜坡曲线以±3 N/s的速率从0线性增加到12 N，然后降低到0 N。拇指和食指的力矢量之间的方向关系进行了量化，使用力矢量之间的协调角（CA）。根据各个力矢量相对于夹捏表面平面的投影角（PA）和这些平面内的剪切角（SA），进一步分析了各个力矢量。结果表明，指尖力的方向取决于捏力的大小，特别是在力低于2 N。在力-CA关系中观察到力增加和力减少的滞后现象，并拟合指数模型。对于增加和减少力斜坡，拟合的渐近值分别为156.0±6.6°和150.8±9.3°。拇指捏力矢量的PA比食指捏力矢量的PA偏离垂直于捏面平面的方向更远。SA显示，食指力向量偏离在尺侧近端方向，而拇指切换其力量之间的尺侧近端和桡侧近端方向。研究结果揭示了精确捏指过程中协调手指力的解剖结构、生物力学功能和神经肌肉控制的影响，并提供了对可能影响一系列灵巧操作的幅度依赖性力方向控制的深入了解。
The human opposable thumb enables the hand to perform dexterous manipulation of objects, which requires well-coordinated digit force vectors. This study investigated the directional coordination of force vectors generated by the thumb and index finger during precision pinch. Fourteen right-handed, healthy subjects were instructed to exert pinch force on an externally stabilized apparatus with the pulps of the thumb and index finger. Subjects applied forces to follow a force-ramp profile that linearly increased from 0 to 12 N and then decreased to 0 N, at a rate of ±3 N/s. Directional relationships between the thumb and index finger force vectors were quantified using the coordination angle (CA) between the force vectors. Individual force vectors were further analyzed according to their projection angles (PAs) with respect to the pinch surface planes and the shear angles (SAs) within those planes. Results demonstrated that fingertip force directions were dependent on pinch force magnitude, especially at forces below 2 N. Hysteresis was observed in the force-CA relationship for increasing and decreasing forces and fitted with exponential models. The fitted asymptotic values were 156.0±6.6° and 150.8±9.3° for increasing and decreasing force ramps, respectively. The PA of the thumb force vector deviated further from the direction perpendicular to the pinching surface planes than that of the index finger. The SA showed that the index finger force vector deviated in the ulnar-proximal direction, whereas the thumb switched its force between the ulnar-proximal and radial-proximal directions. The findings shed light on the effects of anatomical composition, biomechanical function, and neuromuscular control in coordinating digit forces during precision pinch, and provided insight into the magnitude-dependent force directional control which potentially affects a range of dexterous manipulations.
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影响因子：
0.8
作者：
Marquardt TL;Li ZM
通讯作者：
Li ZM
影响因子：
2.4
作者：
Li, ZM
通讯作者：
Li, ZM
DOI：
10.1109/tim.2005.858123
发表时间：
2005-12-01
影响因子：
5.6
作者：
Dun, SC;Li, ZM
通讯作者：
Li, ZM
影响因子：
2
作者：
Moerchen, Victoria A.;Lazarus, JoAnne C.;Gruben, Kreg G.
通讯作者：
Gruben, Kreg G.
影响因子：
2.4
作者：
Serina, ER;Mockensturm, E;Rempel, D
通讯作者：
Rempel, D