## 4 Discussion
On the contrary, the athlete studied by [PERSON] et al. [9] followed a hypocaloric diet, aiming at a 0.57% loss of body mass, and lost approximately \(-\)2.81 kg of fat-free mass while reducing his body mass by \(-\)13.98 kg in 26 weeks, suggesting that the rate of body mass loss is an essential factor in preserving muscle mass. Carbohydrates are essential for high-intensity weightlifting, as inadequate intake can impair performance and hinder muscle growth [22]. They also influence sleep quality, which is critical for recovery and hormonal balance [23,24]. Poor sleep may reduce growth hormone levels and negatively affect muscle hypertrophy [25,26]. Training with repetitions to concentric failure is a training strategy that contributes to muscle retention over time while being in a caloric deficit. The study of [PERSON] et al. [27] showed similar results between training to failure, with 1.6 \(\pm\) 1.8 repetitions short of failure. In contrast, other studies showed superior results with training to failure compared to training with approximately five repetitions shy of failure [28]. The exercise stress is more significant in the last repetitions of a set as there is an increased activation of motor units and mechanical tension, which is the primary mechanism of muscle hypertrophy [29]. This is why the athlete trained at approximately 0-2 RIRs. Despite all these, accompanying muscle fatigue should not be neglected as it can impact recovery [30]. In addition, the phase angle appears to be positively associated with muscle mass, strength, and physical fitness [31,32], but studies that assess this parameter during a diet are limited. The findings in the current study showed a proportional decrease in phase angle with muscle mass and a conversely proportional relationship to the percentage of body fat. It seems that professional athletes have a higher phase angle than non-professional athletes [16]. Future research may focus on the relationship between phase angle and the preservation of muscle mass during a hypocaloric diet. The hormonal profile was also affected during preparation. Research involving humans and mice has shown that significant calorie restriction may lead to lowered concentration of anabolic hormones, such as testosterone and IGF-1 [33,34]. Although strategies like increasing protein intake and incorporating resistance training have been explored to mitigate these effects, their effectiveness appears limited [35]. Several factors influence the extent of hormonal changes [36], including the duration of calorie restriction and the overall energy deficit. Evidence indicates that even brief periods of calorie restriction may diminish androgen levels [37], a condition that worsens with prolonged energy deficits [33,38]. Testosterone levels decreased from 5.4 ng\(\cdot\)mL\({}^{-1}\) to 4.4 ng\(\cdot\)mL\({}^{-1}\), which corresponds to a reduction of 18.5% during the preparation phase, while remaining within the normal physiological range. This decline is considerably less pronounced than the findings reported by [PERSON] et al. [9], who observed a drop from 9.2 ng/mL to 2.27 ng\(\cdot\)mL\({}^{-1}\) (\(-\)75%), and [PERSON] et al. [14], where the levels reduced from 6.23 ng\(\cdot\)mL\({}^{-1}\) to 1.73 ng\(\cdot\)mL\({}^{-1}\) (\(-\)72%), likely because of the reduced deficit utilized in our study [9,14]. The decrease in testosterone is a physiological phenomenon during a hypocaloric diet [39,40], possibly due to reduced fat intake [34,41]. Testosterone is synthesized from cholesterol; a low-fat diet may explain that decrease [34]. Cholesterol is also a precursor of cortisol, but it seems that cortisol increased in the preparation period as it is a catabolic hormone. It appears to be affected by energy deficiency that occurs during a hypocaloric diet [42]. Greater increases were observed in the study of [PERSON] et al. [9] from 10.5 \(\upmu\)g\(\cdot\)dL\({}^{-1}\) to 21.1 \(\upmu\)g\(\cdot\)dL\({}^{-1}\), while they were lower in the study of [PERSON] et al.