## 1 Introduction  
Adaptations to resistance training are often governed by the state of hormones at rest and in response to training. Resistance training has a substantial effect on the endocrine system, particularly training programs that incorporate higher training volumes such as a strength-endurance block used within an accumulation phase of block periodization [1; 2; 3; 4]. The magnitude of hormonal responses following training is closely linked to the intensity and volume of the training session. Consequently, one can anticipate varying hormonal responses depending on the methodology of resistance training. Accentuated eccentric loading (AEL) is a type of resistance training methodology that has gained interest in recent years. AEL takes advantage of the superior force production capabilities of muscles during eccentric contractions and overloads the muscles during the eccentric phase of a movement. This phenomenon results in a greater training load compared to the concentric movement [5]. Using weight releases during cluster sets (CSs) has been suggested as a practical means to apply AEL to multiple repetitions throughout a training set [6]. A cluster set in resistance training is a training technique whereby a set is divided into smaller mini-sets (clusters). The short recovery between the sets reduces fatigue and results in greater overall work performed in a training session. A greater training load, achieved by AEL, may alter the adaptations to resistance training, and while strength-power responses to AEL have been studied [6; 7; 8], the hormonal responses lack sufficient evidence. The balance of hormone concentrations at rest, such as the testosterone-to-cortisol ratio (T:C), can serve as an estimate of the'state' of recovery and as an estimate of the 'anabolic state' [9; 10; 11; 12]. Indeed, the post-resistance exercise hormonal responses such as the levels of growth hormone, testosterone (T), cortisol (C), and the T:C are associated with the rate of protein synthesis [2]. Although the acute responses appear to be relatively minor [13; 14; 15], chronic elevations of such hormones appear to have a substantially great effect on protein synthesis. These hormonal responses have been previously shown to be affected by changes in training volume [10; 16]. High-volume protocols, which are typically used to achieve muscle hypertrophy and increase work capacity, predominantly rely on the glycolytic lactate metabolic pathway. Such training protocols typically stimulate greater post-exercise hormonal responses compared to lower volumes [2]. Interestingly, high-volume programs can produce different effects on endocrine response post-training. The responses to high-volume training depend on the training status of the athlete. For example, short-term high-volume training slightly elevated the resting T and decreased C among previously untrained subjects or males and females [17; 18]. However, resting concentrations of T and the T:C ratio following high-volume programs may be depressed in well-trained subjects. The C level may increase sometimes after only a few weeks and likely reflects how repetitive or difficult the subjects perceived their training monotony and strain [10; 19]. In addition to the T:C ratio, creatinine (CREA) has also been used as a biomarker to monitor physiological responses to training. CREA is largely created from the breakdown of creatine, which is stored in relatively large amounts in skeletal muscles [20; 21]. CREA is excreted through the kidneys, and urinary CREA strongly reflects the amount of muscle mass in the individual [21; 22; 23]. The results of a cross-sectional study indicated that larger muscle masses were accompanied by greater urinary creatinine values among active young men and athletes [24]. Considering that resistance training stimulates hypertrophy [25], particularly programs using higher training volumes, an increase in urinary CREA may beexpected.