the effect of different vision levels and amount of practice on dart throwing accuracy

according to specificity of practice hypothesis, availability of visual information during practice induces performance decrement in no-vision transfer test. one hypothesis is that full vision as a dominant source of information prevents the processing of other sensory sources, in which case, weakened vision may reduce dominance of vision over other sensory sources. the aim of the current study was to examine the effect of different vision levels and amount of practice on dart throwing accuracy. 30 right-handed female students of shahid beheshti university (mean age 22.80±1.47) were voluntarily selected and randomly divided into three groups: full vision, no-vision and weakened vision. the acquisition phase consisted of two phases of low (45 trials) and high (300 trials) amount of practice. mixed model anova (2x3) showed that removing vision had no deteriorating effect at the beginning of the practice , but it had a deteriorating effect after extensive practice in the performance of full vision group (p=0.001). moreover, removing vision did not affect the performance of weakened vision group which could indicate that weakened visual might not prevent the processing of other sources of sensory information. the results of this study supported specificity of practice hypothesis after 300 trials of practice with removing vision. but this hypothesis was not supported with adding vision and dominance of proprioceptive information was not observed. it was likely that dependence on dominant sources of information (vision) appeared sooner while dependence on secondary sources of information (proprioceptive) takes more time and appeared after more trials of practice.