ADAPTED PHYSICAL ACTIVITY QUARTERLY, 1991,8,342-356 Effects of Variability of Practice on the Transfer and Performance of Open and Closed Motor Skiills Thomas A. Eidson University of Akron Robert E. Stadulis Kent State University Schmidt's (1975) schema theory hypothesis of variability of practice on the performance of both a closed and an open motor skill was investigated. Following an acquisition phase for each task, moderately mentally handi- capped (MH) and nonhandicapped (NH) subjects were randomly assigned to either variable or constant practice. For the closed skill, constant practice groups exhibited more absolute error than the variable practice groups during performance of a transfer task. No significant effect of type of practice for the open skill was obtained. For the open skill, MH subjects had significantly greater absolute error and variable error than NH subjects; no performance differences were evidenced for the closed skill. For both MH and NH sub- jects, Schmidt's variability-of-practice hypothesis was supported, but only for closed skills. The study of children's motor skill performance, both handicapped and nonhandicapped, has been investigated in many ways. The purpose of the present study was to examine two major motor learning variables: (a) the type of motor skill being practiced and (b) the method of practice being used, with reference to differences in the learner's cognitive capabilities. If the type of skill and1 or practice interact with the cognitive capabilities of the learner, then different instructional strategies may be needed depending on the capabilities of the learner. The type of motor skill being performed has been suggested as an important variable to consider in the learninglinstruction process. In particular, Gentile (1972) has asserted that skills classified as open or closed should be practiced differently. An open skill, according to Poulton (1957), is one that has an unpre- dictable set of environmental requirements, for example hitting a thrown base- ball. A closed skill, on the other hand, is one that can be performed without a direct response to environmental aspects, for example the shot put. Gentile, Higgins, Miller, and Rosen (1975) extended the openlclosed model and developed a taxonomy of motor skills based upon environmental re- quirements (stablelstationary vs. unstablelmoving) and movement requirements (total body stability, i.e., sitting or standing vs. total body transport, i.e., walking rints from Th~mas~A. Eidson, Memorial Hall, DepaTtment of H ion, The University of Akron, Akron, OH 44325-5103.