Movement direction as well as laterality influence peak velocity of fast hand movements.

With a tv-based computer system, using reflective markers attached to 4 subjects' right index fingers, peak velocities were measured of fast hand movements in both directions between a midline target and left and right sided targets. Peak velocity increased with distance. Movements between the midline and the right sided target (ipsilateral) were faster than those between the midline and left sided target (contralateral). Adduction movements were faster than abduction movements. Retesting two subjects showed a high degree of variability in the peak velocities attained, but the same pattern of faster ipsilateral and adducting movements was found.