EFFECTS OF HEATING ASSOCIATED WITH BLOOD FLOW RESTRICTION ON CARDIAC AUTONOMIC MODULATION AND PHYSICAL PERFORMANCE: RANDOMIZED CROSSOVER CLINICAL TRIAL

• Grant number: 24/15652-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Physiology - Physiology of Effort
• Principal Investigator: Franciele Marques Vanderlei
• Grantee: Gabriel Cena Santos
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

Introduction: The purpose of warming up is to increase muscle and tendon flexibility, improve free and coordinated movement, and stimulate blood flow to distal regions, increasing muscle and body temperature. Thus, the use of blood flow restriction (BFR) is an alternative that will provide greater blood volume and the production of thermal energy in the muscle, generating a more adequate warm-up, in addition to increasing maximum aerobic capacity in athletic populations and improving performance. However, it is known that BFR generates an increase in blood lactate concentration, which is a potent stimulator of chemoreceptors, which, when activated, will stimulate sympathetic flow, subsequently increasing heart rate (HR). Therefore, it is important to investigate the autonomic responses during and after warming up to ensure a safer practical prescription. Objective: to investigate and compare autonomic, cardiovascular, and physical performance responses in the recovery from low-intensity warm-up associated with BFR with low- and high-intensity warm-up. Methods: This is a randomized, crossover, single-blind clinical trial involving soccer players aged 18 to 35 years who will be randomly allocated in a 1:1:1 ratio to one of three groups: i) warm-up at 30% VO2peak; ii) warm-up at 80% VO2peak; and iii) warm-up at 30% VO2peak associated with RFS. Each participant will attend the Center for Studies and Care in Physiotherapy and Rehabilitation - CEAFIR of the FCT/UNESP for seven non-consecutive days, with an interval of at least 72 hours between meetings. Initially, the athletes will be assessed regarding their anthropometric characteristics. After a 10-minute rest, the total occlusion pressure (TOP) will be assessed. Then, the incremental test will be performed to determine the VO2peak, and subsequently, the familiarization session will begin, where the participants will perform the warm-up protocol. After a 72-hour rest, participants will return to CEAFIR to collect functional tests, including the 30-meter sprint test and the vertical jump test. After that, they will perform the warm-up protocol and then the evaluations of the functional tests mentioned above will be performed, following the same order, immediately after the warm-up, as well as 10 and 20 minutes after its completion. Again after a 72-hour rest, participants will return to CEAFIR to collect temperature and RR intervals using a heart rate monitor, where they will be collected for 20 minutes at rest, then during the 15-minute warm-up and 20-minute post-warm-up recovery period. Descriptive statistics will be used and comparisons will be made using the generalized linear mixed model, assuming a significance level of p<0.05.