The Influence of Step Load Periodisation Based on Time Under Tension in Hypoxic Conditions on Hormone Concentrations and Postoperative ACL Rehabilitation of a Judo Athlete: A Case Study

The aim of this study was to determine the effect of a step load periodisation protocol for the rehabilitation of the anterior cruciate ligament (ACL) based on the variables of both the tempo of movement and time under tension (TUT) in normobaric hypoxia using a case study. <b>Introduction</b>: We verified the influence of variables such as time under tension (TUT) and the tempo of movement in hypoxia on the concentration of insulin-like growth factor 1 (IGF-1), growth hormone (GH), and erythropoietin (EPO). The effectiveness of the protocol also concerned variables such as peak torque of the knee flexors and extensors and maximum oxygen uptake (VO₂max), as well as body composition analysis. <b>Methods:</b> The study used a 28-year-old judoka athlete from the national team, competing in the weight category up to 73 kg. <b>Results:</b> The use of short partial rest breaks between series (80s) in combination with six exercises in four series and a hypoxic environment (FiO₂ = 15%) significantly increased metabolic stress, resulting in the highest increase in GH and IGF in the main phase of accumulation of the 3:1 step load. During 16 running sessions, the rehabilitated athlete achieved a significant increase in individual variables in the running test. <b>Conclusions:</b> The combination of a hypoxic environment combined with a periodized rehabilitation protocol can induce a number of positive hormonal, circulatory and respiratory reactions as well as positively influence muscle asymmetry, which can ultimately shorten the time it takes for an athlete to return to sport (RTS).