Effect of lower limb fatigue and performance prediction in CrossFit®

Abstract

Background: The CrossFit® training program, aimed at improving fitness levels, is gaining a significant number of followers worldwide as there is a growing demand for physical exercise and sports to promote good health and avoid a sedentary lifestyle. Aim: The present study aimed to verify the effect of a single CrossFit® training session on the lower-limb relative power and to correlate physical components of body composition, lower-limb relative power, and practice time with physical performance in the Fran benchmark. Material and methods: 21 volunteers (10 males and 11 females), aged 35.7 ± 6.2 years, with a body mass index (BMI) of 26.7 ± 3.1 kg/m² and practice time of 40.8 ± 33.1 months, participated in the study. Before and after training, the following variables were evaluated: jump height, lower-limb relative power, and Rating of Perceived Exertion (RPE), as well as training duration. Results: Lower-limb relative power showed significant differences between the preand post-training instants for men and women (♂ = 27.1 ± 2.1 W/kg, ♀ = 22.8 ± 2.6 W/kg; p < 0.001) and (♂ = 26.4 ± 1.6 W/kg, ♀ = 22.3 ± 2.4 W/kg; p < 0.001), respectively, with a significant reduction in power for men (p < 0.001) (d = 0.42; 95% CI: -0.35 to 1.19) and women (p < 0.005) (d = 0.17; 95% CI: -0.83 to 1.18). Only practice time correlated with Fran's training duration time (r = -0.676; p < 0.01). Conclusion: The results suggest that a single CrossFit® training session can lead to reduced lower limb strength and power and that the practice time is related to the performance of practitioners.