This study investigates the impact of a combined protocol integrating respiratory muscle training (RMT) and ventilatory strategies during exercise on the physiological and performance parameters of professional endurance athletes. Conducted over 48 weeks, the longitudinal intervention involved ten elite cyclists and triathletes. The protocol included inspiratory resistance training using the Powerbreathe® K4 device and isocapnic exercises with the Breathe Way Better® system, applied in a structured and periodized framework. Results revealed significant improvements in respiratory function, including increases in FEV₁, FEV₆, inspiratory flow (PIF), and the S-index. Additionally, ventilatory patterns were optimized, with a marked decrease in respiratory frequency and an increase in tidal volume across all intensities. These adaptations were accompanied by physiological gains such as increased VO₂max, elevated ventilatory thresholds (VT1 and VT2), and improved mechanical power output at all intensities. The study highlights the importance of integrating breathing techniques and respiratory muscle conditioning into endurance training programs. It also emphasizes the need for individualized ventilatory strategies to optimize energy efficiency and delay the onset of respiratory muscle fatigue in competitive settings.