This study aimed to identify the effect of intensive eccentric loading supported by a nutritional supplement (protein-creatine) on some morphological and physical variables and the digital level of throwing competitors. The researchers used the experimental method because it is appropriate for the type and nature of this research through the experimental design using pre- and post-measurements for two experimental groups and a control group. The researchers selected the research sample randomly from the athletics training specialization in the fourth year at the Faculty of Physical Education for Boys, Zagazig University, for the academic year 2024/2025 AD. The number of students is (41), and the researchers chose (5) students for the exploratory study from the research community and outside the basic research sample. Thus, the basic research sample became (36) students who were divided into three groups, each consisting of (12) students. The extracted data were processed using appropriate statistical methods, including the arithmetic mean, standard deviation, Spearman's correlation coefficient, T-test, analysis of variance (L.S.D), Mann-Whitney test equation, Wilcoxon test, and percentage improvement equation. One of the most important results was that intensive decentralized training in the form of training assignments had a statistically significant positive effect and high percentage improvement on the morphological variables and the digital level of the throwing competitors in the experimental groups, in favor of the dimensional measurement. Taking whey protein and creatine supplements with intensive eccentric training led to an improvement in physical variables (throwing arm strength, back and leg muscle strength, muscular endurance, and strength index) in the first experimental group with a greater improvement rate than the second experimental and control groups.