Effects of acute inspiratory loading during treadmill running on cerebral, locomotor and respiratory muscle oxygenation in women soccer players.

Respiratory limitation can be a primary mechanism for exercise cessation in female athletes. This study aimed to assess the effects of inspiratory loading (IL) on intercostal muscles (IM), vastus lateralis (VL) and cerebral (Cox) muscles oxygenation in women soccer players during high-intensity dynamic exercise. Ten female soccer players were randomized to perform in order two constant-load tests on a treadmill until the exhaustion time (Tlim) (100 % of maximal oxygen uptake- (V) over dotO(2)). They breathed freely or against a fixed inspiratory loading (IL) of 41 cm H2O (similar to 30 % of maximal inspiratory pressure). Oxygenated (Delta[OxyHb]), deoxygenated (Delta[DeoxyHb]), total hemoglobin (Delta[tHb]) and tissue saturation index (Delta TSI) were obtained by NIRs. Also, blood lactate [La-] was obtained. IL significantly reduced Tlim (224 +/- 54 vs 78 +/- 20; P < 0.05) and increased [La-], (V) over dotO(2), respiratory cycles and dyspnea when corrected to Tlim (P < 0.05). IL also resulted in decrease of Delta[OxyHb] of Cox and IM during exercise compared with rest condition. In addition, decrease of Delta[OxyHb] was observed on IM during exercise when contrasted with Sham (P < 0.05). Furthermore, significant higher Delta[DeoxyHb] of IM and significant lower Delta[DeoxyHb] of Cox were observed when IL was applied during exercise in contrast with Sham (P < 0.05). These results were accompanied with significant reduction of Delta[tHb] and Delta TSI of IM and VL when IL was applied (P < 0.05). High-intensity exercise with IL decreased respiratory and peripheral muscle oxygenation with negative impact on exercise performance. However, the increase in ventilatory work did not impact cerebral oxygenation in soccer players.