Flanagan J R, Wing A M
MRC Applied Psychology Unit, Cambridge, UK.
Exp Brain Res. 1995;105(3):455-64. doi: 10.1007/BF00233045.
In this paper we examine the coordination of grip force and load during brisk cyclic arm movements with a hand-held object under a range of conditions. We show that, regardless of the surface texture of the object or movement frequency, grip force is modulated in parallel with load. Thus, the tight coupling between grip force and load observed in short-duration tasks such as lifting or point-to-point movements is also seen in longer-duration cyclic movements. Moreover, the gain of the relation between grip force and load remains essentially constant over time. Across conditions, we find a dissociation between the gain of the relation between grip force and load and the grip force offset. With a more slippery surface texture both the gain and offset increase, whereas increases in frequency lead to an increase in the offset but a decrease in gain. This suggests that these two parameters are under independent high-level control. We also observe that when subjects were instructed to maintain a high-baseline grip force during the movement, grip force was still modulated with load even though an increase in grip was not necessary to prevent slip. This suggests that there is an obligatory coupling between grip force and load. This coupling might be subserved by low-level mechanisms not under high-level control.
在本文中，我们研究了在一系列条件下手持物体进行轻快的周期性手臂运动时握力与负载之间的协调性。我们发现，无论物体的表面纹理或运动频率如何，握力都与负载并行调制。因此，在诸如提起或点对点运动等短时间任务中观察到的握力与负载之间的紧密耦合，在较长时间的周期性运动中也能看到。此外，握力与负载之间关系的增益随时间基本保持恒定。在各种条件下，我们发现握力与负载之间关系的增益与握力偏移之间存在分离。表面纹理越滑，增益和偏移都会增加，而频率增加会导致偏移增加但增益降低。这表明这两个参数受独立的高级控制。我们还观察到，当受试者被指示在运动过程中保持高基线握力时，即使增加握力并非防止滑动所必需，握力仍会随负载调制。这表明握力与负载之间存在强制性耦合。这种耦合可能由不受高级控制的低级机制所支持。
