Inspiratory muscles pre-activation in young swimmers submitted to a tethered swimming test: effects on mechanical, physiological, and skin temperature parameters.

Inspiratory muscles pre-activation (IM) has been studied to improve subsequent performance in swimming. However, the effects of IM on various parameters in swimmers are still unknown. Therefore, this study aimed to investigate the effects of IM on the mechanical parameters, physiological responses, and their possible correlations with swimming performance. A total of 14 young swimmers (aged 16 ± 0 years) underwent a 30-s all-out tethered swimming test, preceded or not by IM a load of 40% of the maximal inspiratory pressure (MIP), and with a volume of 2 sets of 15 repetitions. The mechanical (strength, impulse, and fatigue index) and physiological parameters (skin temperature and lactatemia) and the assessment of perceived exertion and dyspnea were monitored in both protocols. The IM used did not increase the swimming force, and skin temperature, decrease blood lactate concentration, or subjective perception of exertion and dyspnea after the high-intensity tethered swimming exercises. Positive correlations were found between mean force and blood lactate (without IM: r = 0.62, P = 0.02; with IM: r = 0.65, P = 0.01). The impulse was positively correlated with blood lactate (without IM: r = 0.71, P < 0.01; with IM: r = 0.56, P = 0.03). Our results suggest that new IM protocols, possibly with increased volume, should be developed in order to improve the performance of young swimmers.