THE EFFECT OF THE INITIAL SHOULDER ANGLE AND ARM ANGULAR VELOCITY ON BALL SPEED DURING THE JUMP SERVE IN MALE HIGH-SCHOOL VOLLEYBALL STUDENTS AGED 16–18 YEARS IN BAGHDAD. International Journal of Advance Research in Education & Literature (ISSN 2208-2441), [S. l.], v. 12, n. 3, p. 58–62, 2026. DOI: 10.61841/frtqcg17. Disponível em: https://jarel.org/index.php/EL/article/view/43. Acesso em: 17 jul. 2026.