Acute and chronic effects of cross fit training on the kinetics of the IGF-I / IGFBPs system in young adults

Abstract

The components of the IGF-I/IGFBPs system constitute a group of growth factors that are directly related to somatic and tissue growth in many species, and exercise programs are related to this anabolic function. The aim of this study was to verify the kinetics of the IGF-I/IGFBPs system in young adults during a CrossFit training program. Eight young adults were evaluated before and after the execution of a standardized training session (Acute effect), during the initial, intermediate and final phases of the CrossFit training program (Chronic effect). To analyze the kinetics of the IGF-I/IGFBPs system throughout the training program, two non-parametric statistical methods were used: the Kruskall-Wallis test for one factor and the Wilcoxon test. The significance level adopted was 0.05. No significant changes were found in the concentrations of IGF-I (p=0.73) and between the initial, intermediate and final phases of the training program. There were also no significant differences in the IGF-I and IGFBP-3 concentrations between the pre and post training sessions in the initial, intermediate and final phases. Even though the standard session was classified between "moderate" and "very difficult", it was not enough to modify the values of IGF-I and IGFBP-3, which can be explained by the participants' practice time and adaptation to intense training, predominant characteristic in the CrossFit modality.