Effects of inspiratory muscle pre-activation on mechanical power and muscle oxygenation during high-intensity effort: studies with active individuals, soccer players and complex network analysis

Author(s)

Anita Brum Marostegan

• Document type: Doctoral Thesis
• Press: Limeira, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Aplicadas
• Defense date: 2022-12-19

Examining board members

Fúlvia de Barros Manchado Gobatto; Wladimir Rafael Beck; Aparecida Maria Catai; Allan Silva Pinto

• Advisor: Fúlvia de Barros Manchado Gobatto; Marlene Aparecida Moreno

Abstract

The present doctoral thesis investigated the effects of inspiratory muscle pre-activation (IMPA) on mechanical and physiological parameters, including muscle oxygenation of the biceps brachii (BB, less active) and vastus lateralis (VL, more active) by near-infrared spectroscopy (NIRS), in two high-intensity efforts with different durations. The first effort was a high-intensity thread running on a non-motorized treadmill (30 s all-out - AO30), performed by 16 active and healthy individuals, under the influence of different IMPA loads, as follows: 15%, 40% and 60% of maximal inspiratory pressure (MIP) and a session without intervention, considered control (Study I – Part 1). Through this first study, it was possible to analyze and understand the responses of the parameters, during and after the effort, identifying the inspiratory load equivalent to 40% of the individual MIP as the intervention that resulted in an improvement of the mechanical and physiological parameters during and after the AO30. Thus, the intervention with this inspiratory load was adopted in the investigation of the effects of IMPA through complex network analysis (Degree and Eigenvector centrality metrics) and implementing the understanding of the adjustments generated by IMPA during and after AO30 in a more integrated way, by analyzing the connections implemented by this intervention (Study I – Part 2). In a second moment, the effects of IMPA were investigated in a soccer field context, being analyzed the impacts of the IMPA during a semi-thread 6 s sprint in a training environment. In this case, 10 soccer athletes were submitted to a sprint test tied to a variable resistance car (CRV) that measures the force, velocity and power data. Furthermore, the oxygenation of more and less active muscles under the influence of 40% of the MIP load was investigated (Study II). The results obtained in this process indicate that using different IMPA loads can improve the performance of physically active individuals submitted to a maximum 30 s tied run, which can be confirmed by increasing the peak, mean and minimum mechanical values during laboratory testing. In addition, the load equivalent to 40% of MIP was able to improve the tissue saturation index (TSI) of BB during the recovery phase, which may indicate greater availability of oxygen to improve the removal of blood lactate produced during high-intensity and short-duration effort. The effects of the 40% load were confirmed by graphs generated by complex network analysis, which were shown to be altered when respiratory intervention preceded exercise, emphasizing muscle oxygenation responses in upper and lower limbs. Blood lactate also played an important role in the observed scenarios, especially after the inspiratory muscle strategy. Our findings confirm that IMPA promotes modulations in the body, better integrating physiological responses, increasing performance and improving recovery. However, even being able to modulate the connections between physiological variables, the effects of this strategy do not seem to impact the responses observed in high intensity and very short duration efforts, since soccer athletes who performed a semi-tied 6 s sprint effort were not benefited by the IMPA performed at 40% of MIP (AU)

• FAPESP's process: 19/20894-2 - Maximal tethered running applied to soccer players and active subjects in two scenarios: investigations about mechanical power and oxygenation in more and less active muscles by complex network model
• Grantee: Anita Brum Marostegan
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)