EFFECTS OF LOW-INTENSITY HEATING ASSOCIATED WITH BLOOD FLOW RESTRICTION ON PHASE ANGLE AND BIOELECTRIC IMPEDANCE VECTORS: A RANDOMIZED CROSSOVER CLINICAL TRIAL

• Grant number: 25/04923-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: December 31, 2025
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Franciele Marques Vanderlei
• Grantee: Milleny Modolo Carvalho
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

Introduction: Warming up is a common practice among athletes and recreational practitioners to prepare the body before training or competitions, with the aim of increasing blood circulation and consequently increasing muscle and body temperature, with the aim of preparing the body for exercise or in pre-competition moments. The increase in body temperature occurs through the exchange of heat from the muscle to the blood and then to the adjacent tissues. Therefore, warming up associated with blood flow restriction (BFR) can be a promising technique, as it maintains arterial inflow and reduces venous return, thus increasing vascular resistance which, together with the mechanical stress of warming up, increases blood volume and consequently the production of thermal energy in the muscle, which can make warming up more effective. However, these effects can have a direct impact on cellular health and integrity, which can be analyzed through bioelectrical impedance analysis (BIA). Objective: to analyze the effects of RFS used during low-intensity warm-up compared with low- and high-intensity warm-up on the phase angle and bioelectrical impedance vectors (BIA). Methods: a controlled crossover clinical trial will be conducted with 108 amateur soccer players (36 per group) aged between 18 and 35 years, randomly divided into three groups: warm-up performed at 30% of peak oxygen consumption (VO 2peak), warm-up performed at 80% VO 2peak, and warm-up performed at 30% VO 2peak associated with RFS (80% of total occlusion pressure). All groups will perform the warm-up protocol and global and localized BIA will be assessed before, immediately after, and 10 and 20 minutes after the end of the warm-up. Descriptive statistics will be used and comparisons will be made using the generalized linear mixed model, assuming a significance level of p<0,05. Keywords: warm-up exercise, vascular occlusion, electrical bioimpedance.