Profile of aerobic and anaerobic response during acute exercise at different domains of intensity and circumstances of swimming

• Grant number: 16/17735-1
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2017
• Effective date (End): December 31, 2017
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Dalton Müller Pessôa Filho
• Grantee: João Guilherme Silva Vieira de Oliveira
• Home Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

During exercise at severe domain, exhaustion is attributed to metabolic acidosis by the disruption of the cell and blood homeostatic balance. Thus, the tolerance can be assessed, inferring on the muscle oxidative capacity (O2 availability and velocity of O2 phosphorylation), anaerobic capacity and efficiency of movement. Especially in swimming, the description of interaction between aerobic/anaerobic demand has an important meaning because depicts the metabolic characteristics typical of most competitive events in swimming (200, 400 and 800 meters). However, the acquisition of respiratory parameters for analysis of aerobic power (VO2max) and the physiological thresholds is faced with two obstacles: (1) disruption of the real condition of swimming by the application of technologies (eg.: Aquatrainer) to capture gas exchange; and (2) lack of fine control of the speed, even with the application of light sources (eg Pacer) due to the frequent acceleration and deceleration in turn phase. For this reason, the swimming in tethered condition (no displacement) is applied as a specific ergometer for swimming because of the possibility of fine control of the application and maintenance of the exercise intensity. However, the absence of the dynamic drag in swimming-raises doubts about the parity of physiological responses to free-swimming, and consequently on ecological validity for the assessment of the athlete and enhancement of competitive performance. These questions could be addressed by experimental designs considering the proportionality of physiological contexts between both circumstances of swimming. The modeling of metabolic response by VO2 kinetics is appropriate to describe the profile of aerobic interaction/anaerobic in each exercise domain and appropriate to compare both swimming contexts, which constitute the objective of this work: to describe the metabolic pattern response in severe domain and the influential factors on swimming tolerance in free and tether conditions. Will be selected at least sixteen trained swimmers of the same sex, belonging to a federated team at ABDA. After obtaining information on the maximum capacity of tether-force and performance in the 200-m, swimmers aerobic capacity and maximal aerobic power will be evaluated in both conditions of swimming (free and tether). Then, observing a period of 24 hours, the swimmers will be submitted to the transitions in severe domain, with prior application of exercise in the moderate domain, in each swim condition: free and tether. In all constant testing phase, the data will be processed by bi-exponential model of VO2 kinetics for the description of the temporal profiles and magnitude of responses. Pulmonary gas exchange will be analyzed breath-by-breath with an automatic portable system (K4b2, Cosmed, Rome, Italy) coupled to the swimmer by a snorkel and specific valve system (Aquatrainer, Cosmed, Italy). The challenge will be to compare the physiological response in both conditions of swimming. So, for the first time in swimming, you can examine whether the particularities of the stroke cycle of the different swimming contexts would provide physiological advantage to tethered-swimming, compared to the free-swimming, as well as its validity in the diagnosis of swimming performance and tolerance. (AU)