There are different indices of training stress of varying complexity to quantification training load. Examples include the training impulse (TRIMP), the session (rating of perceived exertion [RPE]), Lucia’s TRIMP or summated zone score. But the triathlon, a sport to be combined where there are interactions between different segments, is a complication when it comes to quantify the training. The aim of this chapter is to propose a scale to quantify the training load in triathlon simple application.