Caracterização da performance muscular em praticantes de CrossFit

Abstract

Introduction: CrossFit is a sport composed of varied high intensity exercises performed with little or no rest between sets. The practice of CrossFit, characterized by the diversity of exercises and high intensity, imposes a high demand on the musculoskeletal system. However, muscle performance parameters of different joints in this population are still poorly reported in the literature. Objectives: The purpose of this study was to characterize the muscular performance profile of CrossFit practitioners, assessed the influence of sex and dominance. In addition, we also assessed the association of CrossFit years of practice and training volume with muscular performance. Methods: It is a cross-sectional study. The sample was composed of 111 subjects (58 men and 53 women). The participants were submitted to evaluation of isokinetic strength of knee and hip flexors and extensors, and hip abductors in two angular velocities, isometric strength of trunk extensors, shoulder horizontal abductors and scapular retractors muscles and handgrip strength. Descriptive analysis was used to characterize the study variables. Mixed multivariate analyses of variance (MANOVA) were used to compare the isokinetic variables (peak of torque and maximum work normalized by body mass, power, work fatigue and flexors:extensors ratio) of each muscle between sexes and limbs (dominant and non-dominant). The same analysis was used to evaluate the handgrip strength. Independent t-tests were used to compare sexes considering the lumbar and shoulder horizontal abductors and scapular retractors strength variables. Finally, Pearson’s correlation coefficients were used to test if CrossFit years of practice and training volume were associated with isometric strength and peak of torque in the knee and hip joints at 60º/s. Results: Men had better performance than the women in all variables of muscular performance (p< 0,05), except in work fatigue of the flexors and extensors of knee and hip and hip abductors, maximum work of hip flexors at 60º/s, peak torque and maximum work of hip abductors at 60º/s and 240º/s (p> 0,05). In addition, the dominant limb had higher values of handgrip strength (p= 0,002), higher power of knee extensors at 60º/s (p= 0,015), lower values of knee flexors:extensors ratio at 60º/s (p= 0,021) and 300º/s (p= 0,008) and lower work fatigue of knee extensors (p= 0,002). The time of participation in CrossFit was not correlated to muscular performance (p> 0,05). The training volume variable was correlated only with peak torque at 60º/s of knee flexors muscles (r= 0,189; p= 0,048). Conclusion: The present study characterized the muscular performance of CrossFit practitioners. The men had better muscular performance than women, even after normalization by body mass. The absence of asymmetry between dominant and non-dominant limbs for most variables suggests that CrossFit imposes a symmetrical demand on the musculoskeletal system. Finally, the results revealed that the variables related to training did not influence most variables of muscular performance.