The aim of this research is to identify the effect of the detrainingon some physical variables and body composition during the transition period of wrestlers from 17-21 years to the same sample of 18 wrestling players from the MansouraUniversity students for different categories after the end of the training season for the academic year 2015-2016. search time (10) weeks, the researcher used the measurement (age, height, Weight, training  age) and (maximum strength , Strength Endurance Explosive Strength Power, flexibility, Agility), and measurements of body composition   (Weight, fat rate, body mass index (BMI), muscle weigh (LBW), Metabolic Rate (RMR) During rest( and use the researcher descriptive approach method to one group using the prior and Post-test  The results showed that the Detraining of 10 weeks during the transition period negatively affects in some physical variables (maximum strength , Strength Endurance Explosive Strength Power, flexibility, Agility) as well as measurements of body composition (Weight, body mass index, muscle weigh, Metabolic Rate during rest), while a 10-week detraining did not have a significant effect on muscle weight variability for Mansoura University. The most important are the need for medina physical exercise during training or transition periods, such as swimming and running, in order to protect the health level related with body composition and fitness level.