Towards an Integrated Theory of Bimanual Coordination

B. J. Gutnik, J. Nicholson, & D. Nash

The Department of Health Sciences, Faculty of Health Science and Technology, UNITEC, Auckland, New Zealand


This report is a fragment of our broader theoretical scheme, "Towards an Integrated Theory of Bimanual Coordination", and reflects lateralized spatial strategies in fast manual movements involving mainly isotonic muscle contraction.

The spatial kinematic characteristics and lateral differences between the two upper extremities were investigated in unilateral graphical tasks involving fast and precise oscillating movements in the vertical two dimensional plane. The spatial location of actual reversal points and the combination of different projectiles were used to identify one particular variant of motor performance often used by both extremities, that is, one with a strong pattern of intermittent large and small angles. The performances affiliated to this variant mostly operated with reciprocal alterations in the magnitudes of the X and Y vectors for the right arm and concurrent collaboration between them for the left arm. Left-performed charts seem to be larger and more symmetrical than those created by the right arm with a much higher level of predictability of alteration in tangential angles recovered from points representing 5% distances along each line connecting two reversal points.

It is suggested that this spatial movement strategy might reflect several different schemes of motor control where coupling of oscillators controls vertical and horizontal movements. It is also suggested that specific subunits of the functional system of nervous elements responsible for the expression of spatial derivatives of motor programs exist at lower levels of the CNS, immanently determining different lateralized spatial behaviours.