Abstract
This study sought to establish an optimal inspiratory warm-up (IWU) protocol for elite 400-meter athletes. It addresses the existing gap in sprint-specific research and provides practical applications for coaches and athletes aiming to optimize sprint running performance. Across four weeks, 13 elite male runners (age: 22.7 ± 2, personal best: 50.78 ± 0.65 s) performed four 400-meter time trials after different warm-up protocols in a randomized order. Assessments of various respiratory variables [maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), peak inspiratory flow rate (PIFR), inhaled volume (IV)] and selected physiological indices [heart rate (HR) and blood lactate (bLa)] were performed before and after the time trials. Analysis of variance with a significance level of p < 0.05 was applied. Incorporating IWU into a standard running warm-up resulted in a ~ 0.38-second faster 400-meter time trial in elite male sprinters (p < 0.001). The most effective IWU protocols, associated with the fastest run splits, consist of two sets of 30 dynamic inspiratory maneuvers performed with pressure threshold loading at 40% or 60% of MIP resistance. These protocols exhibited a positive influence on selected respiratory indices and significantly lowered post-run lactate concentrations compared to the athletic warm-up and sham protocol. IWU with 40% MIP resistance was associated with lower post-run HR compared to other protocols. IWU using pressure threshold loading at either 40% or 60% of MIP can be beneficial for elite male sprinters. While 40% MIP appears to support faster recovery, a higher intensity at 60% MIP shows greater effectiveness in enhancing 400-meter sprint performance. Future research should explore IWU applications across broader populations and conditions, including female athletes, various hypoxic environments, and temperature variations.