


Muscle afferent responses to imposed movements about two axes of the ankle have been described in a recent study ( Bergenheim et al. This paper presents the first report of human muscle afferent activity during voluntary multi-degree of freedom hand movements that give rise to a complex pattern of active length changes. For example, it is not clear how the data from simple flexion/extension movements at the finger should be extrapolated to more complex movements.

However very little is known about the expected patterns of sensory information arising from human muscle afferents when volitional movements make use of several degrees of freedom available at a given joint. Theoretical models of motor control and psychophysical results posit roles for such sensory feedback in higher order processes such as motor planning, motor prediction, state estimation and motor learning ( Jeannerod, 1988 Scott & Loeb, 1994 Wolpert, 1997). It is well established that sensory activity arising from muscle afferents contributes not only to segmental feedback control of movement, but also to the conscious coding of position and movement in humans ( Goodwin et al.
