This thesis has five chapters. This study is aimed at investigating the effect of training load application on the improvement of physical fitness level of student trainees: in case of Shindi high and preparatory school. In order to achieve this objective fitness tests were administered. The researcher used repeated measurement experimental design method and simple random sampling techniques for selecting students who took part in the study. The sample size of this study was 30 students (15 male and 15 female) and the study has experimental and control group, selected students were categorized in both groups by using simple random sampling method. The experimental group students were engaged in training program 3days per a week for 12 weeks with moderate intensity as stated from (appendix III) but the control group students are advised to stay as usual. Fitness tests in health and skill related fitness components of selected variables took two times at the beginning (pre test) and at the end (post test) of the training session which were used as tools of data gathering instruments. Data were analyzed by using paired sample T-test to compare the two groups and it was used with the help of statistical package software (SPSS version 20.0) to find the significant difference between the two groups with 5% error, two tail hypothesis test and equal variance assumption. In all cases after the application of training load mean and mean difference value showed there was significance difference between two groups in selected physical fitness variables at p<0.05 and at (t value 0.975) and in all cases level of confidence(0.05) was fixed to test the significance. Accordingly, the overall study revealed that there were significant changes on the fitness level of student trainees. The study concluded that when regular physical activity is following correct principles of physical fitness training load: it can help to improve the agility, speed, strength, endurance, flexibility level of the student. Thus the recommendations for addressing the issue include other high and preparatory schools to fulfill some important materials and facilities. Based on this the researcher recommend that students should participate in regular physical exercise in order to enhance their fitness level. And PE professionals and trainees should also follow correct principles of physical fitness training, and finally government should revise the curriculum to settle the standardized PE class per a week in school to achieve the desired objectives.