Training in accordance to oxygen differential threshold and its impact on the heart metabolic need and the two cortisol and growth hormones for the advanced 1500m runners. Period. Eng. Nat. Sci. [Internet]. 2021 Sep. 30 [cited 2026 Apr. 18];9(4):1-4. Available from: https://pen.ius.edu.ba/index.php/pen/article/view/925