Both coaches and cyclists nowadays determine the training schedules for important races based on experience and gut-feeling. Data are available for the evaluation of training schedules, but a sound scientific method of accomplishing this does not yet exist. The biggest hurdle in developing such a method for cycling is the absence of an objective performance metric. This report uses the data of six cyclists in order to introduce and analyze a new performance metric: the cycled critical power. Subsequently, this metric is used to fit the parameters of the Fitness-Fatigue model; a model that is successfully applied in other sports to model the performance of an athlete. Several training attributes are included in the analysis, such as duration, intensity, and load; with which the performance of the cyclists is modeled. The model, applied to the data, leads to correlations for the six cyclists with R2-values within the range of 0.13 - 0.56. Compared to other scientific research, this range indicates that the Fitness-Fatigue model could be a valuable tool for elite cyclists and coaches when constructing their training schedules, but further research into the performance metric and the application of the Fitness-Fatigue model is still required.