Free testosterone/cortisol ratio in soccer: usefulness of a categorization of values

The free testosterone:cortisol ratio (FTCR) is widely used for studying and preventing overtraining syndrome in various sports. The use of FTCR for following overtraining syndrome was proposed originally with two approaches: FTCR lower than 0.35x10(-3), calculated on free testosterone (FT) in nanomoles per liter (nmol/L) and on cortisol (C) in micromoles per liter (mmole/L) or a decrease of the ratio of 30% or more in comparison with the previous value. In our experience, the use of an absolute value as a threshold is not useful, whereas the evaluation of the concentrations of hormones and their ratio in comparison with previous ones is more useful. These classical approaches are not, however, sufficient to describe the various possible physiological modifications linked to training excess and/or incomplete recovery.