Santillan Chillambo DX, Angulo Caicedo RA. Impact Assessment of a Functional Training Program on Upper Body Strength and Performance of Under-15 Youth Goalkeepers: A Quasi-Experimental Study in Esmeraldas . EKSIGMA. 2026;2(1):82-98. Accessed April 16, 2026. https://eksigma.com/index.php/principal/article/view/20