Paper Title
Effects of Concurrent Training on Testosterone and Cortisol in Males

Abstract
Training principles are designed to improve performance by developing the appropriate energy sources, increasing muscular structures, and improving adaptation in neuro-muscular skill patterns. The aim of the present study was to investigate the effects of concurrent strength and endurance training on physical performance and hormone profile levels in 24 untrained males were trained for 12 weeks. Subjects were divided into three training groups separated by the strength, endurance and concurrent training mode. Each group had an equal number of subjects (8) and were studied during a time course of 12 weeks. Blood samples were drawn from the left brachial vessel at 0, 6 and 12 weeks to determine the total and free concentrations of testosterone and cortisol.The concentrations of total and free testosterone in the strength and concurrent groups were significantly increased (a ≤ 0.05). The total testosterone/cortisol ratio in the strength group increased after 6 weeks and declined at the end of the 12th week. The cortisol concentration did not significantly change in any of groups studied after 6 and 12 weeks (a ≤ 0.05). The concurrent training group exhibited a lower increase in strength, whereas the strength training group exhibited a higher increase in strength. It is likely that concurrent training leads to an improvement in the adaptation that occurs between the endocrine system and muscular performance. Keywords - Concurrent Training, Anabolic and Catabolic Hormones, Serum Testosterone/ Cortisol Ratio