PubMed1984
Ninety-six normal left-handed children were tested for motor co-ordination on a series of timed repetitive tasks, alternating left and right hands, feet and fingers. Preferred hand advantage could be demonstrated to the same degree for the left hand of these children as it had been for the preferred right hand in previously studied groups of the same age (Denckla 1973, 1974). The only test (finger to thumb successive opposition) that failed to show a preferred hand advantage in left-handers also had failed to show such an advantage among right-handers. This same test was performed more rapidly by left-handed girls than boys, as it had been by right-handed girls. However, left-foot superiority appeared to be less well established among left-handers than superiority of the right foot among right-handers, and at a later age. Left-handed children were less likely than their right-handed counterparts to choose their preferred hand when trying out a new task. Writing posture, i.e. whether inverted or straight, could not be established unambiguously for the left-handed children up to the age of 10, and often differed for writing and printing.