Nagham Hatem Hameed, Haider Faiq Al-Shamaa, Firas Haider. Preparing movement exercises using a proposed laser device on the heel of the foot to learn and develop the speed of rotation and accomplish to the discus throw for youth U 20. ms [Internet]. 2024 Mar. 30 [cited 2024 May 8];23(1):0123-3. Available from: https://jcopew.uobaghdad.edu.iq/index.php/sport/article/view/1266