%0 Journal Article %T The Effect of Psychological Skills Training (Goal Setting, Positive Selftalk and Imagery) on Self-Confidence of Adolescent Volleyball Players %A A. Heydari %A H. Soltani %A Moammadi Nezhad, Mahdi %J Pedagogics, psychology, medical - biological problems of physical training and sports %@ 1818-9172 %D 2018