Inspiratory muscle strength affects anaerobic endurance in professional athletes.

To the best of our knowledge, little is known about the role of respiratory muscle strength and endurance on athlete performance in anaerobic conditions of maximal exertion. The aim of this cross-sectional study was therefore to examine the association between the strength/endurance of inspiratory muscles in a group of 70 healthy male professional athletes (team sports) and their ventilatory and metabolic parameters at the anaerobic threshold (second ventilatory threshold; VT2) and beyond it at maximum load during the cardiopulmonary exercise test (CPET) on a treadmill. Ventilatory parameters at VT2, at maximal effort, and their differences were tested for association with inspiratory muscle strength (PImax) and endurance (Tlim), measured as time to maintain inspiration at or above 80% of PImax. The difference in end-tidal oxygen tension (ΔPETO2) between VT2 and maximal effort was significantly associated with resting heart rate (HR) and systolic blood pressure (BP), PImax, and lean body mass (LBM) (r2=0.26, p=0.016; multivariate regression analysis). The difference in carbon dioxide output (ΔVCO2) was significantly associated with body mass index (BMI), resting HR, systolic BP, and PImax (r2=0.25, p=0.022; multivariate regression analysis). Our findings suggest that it is the inspiratory muscle strength and not endurance that affects the performance of professional athletes and that it should be tested and trained systematically.