علی صدقیان

This study aimed at determining the effect of cathodal Transcranial Direct-Current Stimulation (c-tDCS) of Dorsolateral Prefrontal Cortex (DLPFC) on learning simple volleyball serves. This semi-experimental study was performed as pre-test and post-test with a control group. Thirty male volleyball players with an average age of 14±0.50 years were selected through purposeful sampling based on inclusion and exclusion criteria. The participants were randomly assigned to experimental (n=15) and control (n=15) groups. During eight consecutive sessions, the left DLPFC of participants was stimulated for 10 min using sham and real c-tDCS of 1.5 mA before each session. The participants then performed 35 simple volleyball serves. Absolute error and total variability of participants' performance in pre-test, in the first, third and eighth sessions were recorded. Data analysis by repeated-measures showed that there was a significant difference between absolute error (F=14.597, P = 0.001) and total variability (F=17.523, P = 0.001) of experimental and control group performance. ANCOVA showed that absolute error and total variability of the experimental group performance was respectively (P = 0.013 and P = 0.018) in the first session, (P = 0.021 and P = 0.007) in the third session and (P = 0.001 and P = 0.001) in the eighth session, which were significantly higher than that in the control group. Thus, it seems that c-tDCS of DLPFC is associated with reduced declarative memory activity in the cognitive stage leading to a negative impact on serve learning in beginner volleyball learners.