Abstract
Background/Aim: The critical power (CP) concept has been widely applied to different exercises and muscles. However, we did not find studies that applied this concept to the respiratory muscles. The aim of this study is to determine the inspiratory critical pressure (PthC) in healthy men.
Methods: We evaluated 41 physically active healthy men, aged between 20-60 years (35±12years). They were submitted to a cardiopulmonary exercise test, a maximal inspiratory pressure (MIP) assessment, and to the PthC protocol. The PthC consisted of a progressive threshold loading test (Neves, L.M.T et al. Heart & Lung, 2012; 41:137-145) using a linear inspiratory load resistor (PowerBreathe® K5), to set the maximal load sustained for at least 1 minute (PTHmax). After this, three different percentages of PTHmax (95%, 100% and 105%PTHmax) were randomly applied during a constant test until task failure (TLim). The TLim of each constant load was used to calculate the PthC, which was obtained by a linear regression going through the three points loads. We applied a linear stepwise regression to evaluate the influence of age and anthropometric data on the PthC (p<0.05).
Results: PthC was 122±16cmH2O with TLim of 1202±525s, and this value represent 83±7%MIP and 92±5%PTHmax. We found that the PthC values (r2:0.28, β:-0.53, p=0.002) and %PTHmax (r2:0.23, β:-0.48, p=0.002) were influenced by age, and the TLim showed an interaction between age and weight(r2:0.26, β:0.51, p=0.002).
Conclusions: The PthC percent is similar to other CP values of the literature; age influenced the PthC load and %PTHmax. These results suggest that the concept of PthC might be applied as a new tool to the respiratory muscle training.
Financial support: CNPq.
- Copyright ©ERS 2015
