Based upon predictions of equilibrium-point (EP) models of motor control, a
recent article by Jaric et al. (1999) [Hla, tan Movement Sciences, 18, 49-
66] reported that the peak velocity (PV) of an inertially loaded single deg
ree-of-freedom elbow movement was not altered to a statistically distinguis
hable degree by the accuracy of the subject's expectation about the size of
the load. They concluded that their results confirmed their EP models and
were incompatible with what they described as torque-control models. A revi
ew of the literature and analysis of a more extensive set of data does not
support that conclusion. To the contrary. if the actual load is heavier (or
lighter) than expected, it is moved more slowly (or faster) than it would
have been, had expectation matched reality. Torque-control models predict t
hose consequences, EP models do not, (C) 2000 Published by Elsevier Science
B.V.