Introduction: Training individualization is a key element for optimal sports performance and protection of the athlete’s health. The training program should be adjusted according to each athlete's characteristics and should be based on data obtained using proper evaluation. Cardiopulmonary exercise testing (CPET) is considered the gold standard for aerobic exercise capacity assessment and provides an increased quantity of information in regard to body reaction to effort, offering a complete perspective over the O2 transportation system and its utilization in metabolic processes. The aim of this study was to highlight the importance of a scientific approach regarding the physical training, starting from junior level. Methods: For a 3 years period (2013 - 2016) we followed the evolution of a professional cyclist (14 years old at baseline), in terms of cardiopulmonary parameters. During this period, he was tested 5 times and he followed a special training program adapted according the tests results. The CPET was performed in the laboratory using a stationary electronically braked cycle ergometer (Lode Corival, Netherland) and a breath by breath gas analyzer device (Cortex Metalyzer 3B, Germany). Results: We observed an improvement trend in almost all parameters investigated during the 3 years evaluation period. Comparing post-season records from 2013 and 2016, we noticed an increase of 54% in maximal aerobic power and 50% in peak oxygen uptake at anaerobic threshold and an even greater increase (59%) of these parameters at maximal effort achieved during CPET. After these 3 years of training we observed a significant improvement of ventilatory efficiency and cardiac performance during exercise. Conclusions: The study indicate that proper training adaptation according to data obtained using CPET, can bring an important progress in terms of performance.