ملخص الدراسة:

The Aim of the study identify to - Effect of step – length exercises on Special power Endurance and characteristic speed and power and completion of running 400 meter under 18 years .- Effect of power frequency exercises on Special power Endurance and characteristic speed and power and completion of running 400 meter under 18 years .- Effect of length and frequency of step on Special power Endurance and characteristic speed and power and completion 400 meter under 18 years .- statistical differences for three research groups in Special power Endurance and characteristic speed and power and achievement .The researcher assumed :There are statistical differences between pre and posttests results in the development of of physical variables between research groups.- There are statistical differences between pre and posttests results in the development of achievement between research groups. - There are statistical differences between posttests results in the development o in physical variables and achievement between research groups. The researcher used the experimental method with the three experimental groups as it fits the research and the problem to be discussed , the research consists of the team of Kirkuk and the 15 players were selected 12 players representing the sample of the research was divided into three groups according to the experimental variable and in a lottery each group of 4 players were excluded 3 who conducted the pilot experiment .the test sample was tested beforehand on (Tuesday-Thursday) on (6-29-26) on al thawra sports club in Kirkuk and the researcher relied on a number of kinetic variables in order to develop training exercises to develop the 400meter free run and special physical abilities , step length exercises , step frequency exercises , and both of them length and frequency of step , the main period is 8 weeks with 5 units per week , after applying the exercises to the members of research sample and ending the period of the main experiment , the researcher returned the after actions ( physical capacity measurement and measuring the level of achievement ) the same before test. The researcher reached a number of conclusion: - step length exercises have a positive effect on year own physical abilities. - step length exercises have a positive effect on the running 400 meter.- The length and frequency of the step positively effect the completion of running 400 meter . - The step frequency had a slight effect on the wide jumping , running in jumpo running 300 meter , running 400 meters .