Kinematic and performance analysis of the lower limbs after induced muscle fatigue in Crossfit athletes

• Grant number: 23/12962-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2024
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Enrico Fuini Puggina
• Grantee: Gabriel Vital Martins
• Host Institution: Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Crossfit is a type of training that involves high-intensity intermittent and functional exercises that is recently growing in the context of physical conditioning improvement strategies. During its practice, due to the high demand of muscular effort, the process of fatigue (failure of strength in some muscles of the body) is common to occur. Fatigue affects motor performance and body biomechanics, which may lead to incorrect execution of certain movements and a higher predisposition to injuries in sports. In this context, the aim of this study will be to verify the influence of fatigue induced by jumps on the quality of movement and on the angles of the lower limb joints, using kinematic and performance analyses. Kinemetry is one of the methods used to evaluate the quality of movements and angulations during sports practice and manages to demonstrate the change in each type of movement studied, when subjected to different situations. Performance evaluation, on the other hand, illustrates the response to training programs, especially when subjected to efforts capable of breaking the body's homeostasis. For this purpose, 20 participants (sample size calculated by using the G*Power software), for individuals aged between 18 and 40 years, will be submitted to strength and muscular power tests through jumps (countermovement jump, squat jump and drop jump with 40 cm) before and after (immediately after, one hour after, two hours after, 4 hours after and 24 hours after) a fatigue induction protocol, and compared to a test with the same parameters, without the induction of fatigue. The kinematics analysis will be performed using the Kinovea® software, in which the joint angulations of the involved movements will be verified. The performance analysis will be carried out based on the information obtained by the Jump System Pro sensorized mat (CEFISE, Sorocaba, Brazil), from the flight time of each jump. For the statistical analysis, the Shapiro-Wilk statistical test will verify the normality of the data. The mixed models ANOVA test will verify the presence or absence of differences between the variables of each jump before and after the fatigue protocol. In case of detection of differences, the Tukey test will be performed to detect occurrences.