This target article presents a critical survey of the
scientific literature dealing with the speed/accuracy trade-offs
in rapid-aimed movements. It highlights the numerous mathematical
and theoretical interpretations that have been proposed in recent
decades. Although the variety of points of view reflects the richness
of the field and the high degree of interest that such basic phenomena attract in the understanding of human movements, it calls into
question the ability of many models to explain the basic observations
consistently reported in the field. This target article summarizes the
kinematic theory of rapid human movements, proposed recently by R.
Plamondon (1993b; 1993c; 1995a; 1995b), and analyzes its predictions
in the context of speed/accuracy trade-offs. Data from human
movement literature are reanalyzed and reinterpreted in the context
of the new theory. It is shown that the various aspects of speed/
accuracy trade-offs can be taken into account by considering the
asymptotic behavior of a large number of coupled linear systems,
from which a delta-lognormal law can be derived to describe the
velocity profile of an end-effector driven by a neuromuscular synergy.
This law not only describes velocity profiles almost perfectly, it
also predicts the kinematic properties of simple rapid movements
and provides a consistent framework for the analysis of different
types of speed/accuracy trade-offs using a quadratic (or power)
law that emerges from the model.