The purpose of ihis study was to compare the effects of a single practice session on performance strategies used by young and older adults to decrease movement time (MT) while maintaining accuracy of an aiming task. Five young and 5 older adult males practiced until each accumulated 500 target hits in each of two complexity conditions as defined by Fitts’s law. Participants decreased MT with practice; however, older adults had longer MTs than the young, particularly in the high-complexity condition. With practice in the low-complexity condition, participants decreased absolute acceleration and deceleration times but maintained the relative amount of MT devoted to temporal phases. In contrast, with practice in the high-complexity condition, participants decreased absolute deceleration and dwell time and changed the temporal structure. Results suggest that older adults can decrease MT with practice and that the performance strategies adopted to speed performance are more a function of task complexity than age.
Patricia S. Pohl was with the Department of Biokinesiology and Physical Therapy, University of Southern California, at the time of this study and is now with the Department of Physical Therapy Education and the Center on Aging. University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160-7601. Carolee J. Winstein is with the Department of Biokinesiology and Physical Therapy, University of Southern California.