The main objective of this thesis was to gather as much relevant information as possible into the similarities and differences for competitive cyclists and triathletes in relation to their cycling training, specifically the phase of training known as the base preparation, during the winter months where varying climatic conditions do not allow conduction of training process on the open road. It is fair to say that there is a lack of depth to the professional literature that covers the parallel analysis of indoor cycling in examples of cyclists and triathletes. This papers hypothesis introduces us to the most important bonds and major differences of both sports, whilst also providing guidelines for optimal performance in relation to the training process. Conceptual examples, means of diagnostics, working tools of one micro-cycle and one detailed indoor cycling training programme in both sports are presented in the paper and will help with the understanding of different training concepts. Discussion was raised to question the usefulness of cycling training tools in triathlon and vice versa, in the form of making better progress in both sports. Attention is being focused on understanding the importance of differentiating winter preparation in regard to cycle training in both sports with respect to the total training volume.