The importance of studying the effect of playing simulation exercises in the chest wall and the various defensive moves of handball players (15-18 years old), in an effort to find out the effectiveness of this type of exercise in the development of comprehensive defensive performance, and achieving integration between the skill side and the plans of the juniors, to build a scientific training base that contributes to the preparation of players capable of defensive performance with high efficiency in the later stages, the research problem was summarized by the following question: Does the use of playing simulation exercises contribute to the development of the level of defensive performance, especially in the chest wall and defensive moves the variety of defensive abilities of handball players of the category (15-18 years old) compared to traditional training methods، The objectives of the research were to prepare play simulation exercises to develop the chest wall and various defensive moves for handball players (15-18) years, and to identify the results of play simulation exercises in the development of the chest wall and various defensive moves for handball players (15-18) years. The researchers used the experimental method with two experimental and control groups to fit the research problem, the research community consisted of the players of the Maysan handball education team for the academic year 2023-2024, numbering 16 players, the players were divided in a random way into two experimental and control groups with (6) players for each group, players were excluded for the exploratory experiment and other players being goalkeepers, homogenization was carried out between the two groups for variables (height, weight, chronological age, training age), appropriate devices and tools were used, as well as appropriate tests and measurements for the studied variables the statistical bag (SPSS) was used.26) to process the results were analyzed And to discuss the results according to modern scientific sources to reach conclusions from them (there is a clear superiority of the dimensional tests of the experimental and control groups over the tribal tests in the research variables, and there is a superiority of the dimensional tests of the experimental group at the expense of the dimensional tests of the experimental group in the research variables) as for the recommendations, including (the inclusion of simulation exercises of playing regularly within the curricula of handball training in general, especially the age groups, and the design of exercises so that they are with real positions of play and include changing directions quickly, correct positioning, interaction with the ball and colleagues).