Reschechtko Sasha, Zatsiorsky Vladimir M, Latash Mark L
a Department of Kinesiology , The Pennsylvania State University , University Park.
J Mot Behav. 2015;47(5):365-77. doi: 10.1080/00222895.2014.996281. Epub 2015 Jan 7.
The authors explored task-specific stability during accurate multifinger force production tasks with different numbers of instructed fingers. Subjects performed steady-state isometric force production tasks and were instructed not to interfere voluntarily with transient lifting-and-lowering perturbations applied to the index finger. The main results were (a) intertrial variance in the space of finger modes at steady states was larger within the subspace that had no effect on the total force (the uncontrolled manifold [UCM]); (b) perturbations caused large deviations of finger modes within the UCM (motor equivalence); and (c) deviations caused by the perturbation showed larger variance within the UCM. No significant effects of the number of task fingers were noted in any of the 3 indicators. The results are discussed within the frameworks of the UCM and referent configuration hypotheses. The authors conclude, in particular, that all the tasks were effectively 4-finger tasks with different involvement of task and nontask fingers.
作者们在使用不同数量指示手指的精确多指力产生任务中探究了任务特定稳定性。受试者执行稳态等长力产生任务，并被指示不要主动干扰施加于食指的瞬态升降扰动。主要结果为：(a) 在对总力无影响的子空间（非受控流形[UCM]）内，稳态时手指模式空间中的试验间方差更大；(b) 扰动导致UCM内手指模式出现较大偏差（运动等效性）；(c) 扰动引起的偏差在UCM内表现出更大的方差。在这3个指标中，均未发现任务手指数量有显著影响。研究结果在UCM和参考构型假说的框架内进行了讨论。作者们特别得出结论，即所有任务实际上都是4指任务，只是任务手指和非任务手指的参与程度不同。
