Critical Flicker Fusion (CFF) is defined as the light stimulus frequency from which it is perceived as a stable and continuous sensation. Its utility in sports training context is focused in its relation with the activation and fatigue level of central nervous system (CNS). If CFF increases it is considered that the activation level is higher, and obviously, if it decreases, the activation level is lower. Scores below baseline are related to a fatigue of CNS. As it can be easily assumed, each sporting modality requires an optimum level of activation in order to obtain peak sporting performance. The present study introduces CFF in sports training control. The main goal was to find out if it exists any relationship between CFF and various physical effort types that evolve different demands of aerobic and lactic anaerobic endurance. The obtained results show significant statistic differences between the activation level, and the CFF values before and after the various physical effort tasks. In all of the experimental situations, the applied training has implied a CFF increment. Finally, we have not find significant statistic differences in relation to the CFF level of activation between aerobic intensive and anaerobic lactic efforts.<\/p>\n\n