<b>Acute effects of inspiratory muscle warm-up on muscular performance and pulmonary function in natural bodybuilders</b>

Background: Inspiratory muscle warm-up (IWU) has been hypothesized to enhance athletic performance by pre-activating respiratory muscles; however, evidence in professional natural bodybuilders is scarce. The present study investigated the acute effects of IWU on one-repetition maximum (1RM) bench press performance and pulmonary function. Methods: The present randomized controlled experimental study comprised 20 male athletes with an average training experience of 3.21 ± 1.44 years, who trained for more than 5 hours per week and had participated in national or international competitions. At the commencement of the study, all participants underwent a series of pulmonary function tests (PFTs), measurements of maximal inspiratory and expiratory pressures (MIP and MEP), and a one-repetition maximum (1RM) test. Following the initial assessments, which were conducted seventy-two hours prior, participants were randomly assigned to either the IWU group (n = 10) or the control (CON) group (n = 10). While the IWU group performed both inspiratory muscle warm-up and standard exercise warm-up, the CON group performed only the standard warm-up. Subsequent to the execution of the warm-up protocols, both groups were subjected to re-evaluation through the means of the 1RM test and respiratory parameter measurements. Results: The IWU group demonstrated a 5.96% greater enhancement in 1RM performance in comparison to the control group (p < 0.001). Furthermore, significant increases were observed in FVC, FEV1, and FEV1/FVC following IWU, with improvements of 2.57%, 2.44%, and 2.65%, respectively (p< 0.001). Furthermore, an additional 2.39% enhancement in MEP was identified in favour of the IWU group (p = 0.008). The alterations in MIP and PEF exhibited by the two groups were analogous, with no statistically significant disparities observed (p > 0.05). Conclusions: The present study has demonstrated that IWU has the capacity to rapidly enhance maximal strength and respiratory function in professional bodybuilders. Consequently, IWU can be advocated as an efficacious warm-up technique to augment exercise performance in bodybuilding athletes.