Sabri, Jamal, and Ammar Makki. “Jumping from Relationship Stability and Movement (vertical, horizontal)level Bottom of the Foot (medial Arch) and Descriptive Research on Theplayers of Najaf to the Speed Events, Jumping Youth Athletics”. Journal of Physical Education, vol. 24, no. 1, Mar. 2012, p. 27, https://jcope.uobaghdad.edu.iq/index.php/jcope/article/view/1852.