The purpose of the current study was the effect of 8-week high intensity resistance training (the Split training method), on Testosterone, Cortisol and Testosterone/Cortisol serum level and its influence on muscle mass and development of muscle strength. 20 persons beginner in bodybuilding (body mass index: 23.80±2.25 kg/m2; age: 24.65±2.55 year) participated in this study. The subjects divided randomly into strength training (10 persons) and control groups (10 persons). Training program was designed according to the Split method with 85%-100% of 1RM for six times per weeks. The same strength and duration was applied for the control group based on the traditional training. Before and after training the thickness of Triceps muscle was measured with ultrasound in both groups. Resting blood samples were collected before and after training. The results showed, compared with traditional training, training with Split method increased muscle strength (p=0.01), muscle mass (p=0.001) and the Testosterone to Cortisol (T/C) ratio (p=0.02). Moreover, there were significant correlation between the maximum strength and hypertrophy(r=0/55, p=0/001) and between (T/C) and maximum strength (r=0/74, p=0/03). The results of this study shows that resistance training with high intensity (the Split Training Method) causes increase in anabolic stimulation and muscle mass which subsequently increases maximum strength.
