CAN NONLINEAR MUSCLE DYNAMICS EXPLAIN THE SMOOTHNESS OF HANDWRITING MOVEMENTS

The paper addresses the issue of the role of non-linear muscle dynamic s in determining the smoothness and invariance of handwriting trajecto ries. In particular, a specific neuromuscular control model is describ ed that has recently been shown to explain the detailed time course of hand stiffness during arm reaching movements. In the paper the model is applied to more complex handwriting trajectories, with the purpose of verifying to which extent the load compensation capabilities of the periphery can subserve motor equivalence. Simulations show the power of the mechanism for movements of ''normal'' speed. For quicker moveme nts periphery alone is not enough and a central load compensation acti on is clearly required. (C) 1998 Elsevier Science B.V. All rights rese rved. PsycINFO classification: 2330.