Background: The purpose of this paper is to identify the effect of assisted training using branched-chain amino acids supplementation (BCAA) in developing the special strength and accuracy of offensive skills in volleyball for youth. Methods: The researchers used the experimental method in the style of the two groups (control and the experimental) due to its suitability to the research problem. The players of Al-Muqdadiya Sports Club represented the research sample, ages (18-19) years, who numbered (15) players and they were divided into two cases and control groups and for each group (6) players and (3) players, the reconnaissance experiment was conducted on them. The curriculum was applied to them for a period of two months, at the rate of (3) training units per week, where pre and post-tests were conducted, then data were collected and processed statistically with the (SPSS) program, and the results obtained Results: There are significant differences in favor of the experimental group and for all special strength tests at the expense of the control group. Conclusion: The supplement (BCAA) had a positive effect on improving the level of physical performance in volleyball, and the physical exercises had a positive role in the development of the accuracy of the performance of the players by using them as an aid in the training units.