## 4 Discussion  
The aim of this systematic review was to consolidate the methodologies employed in measuring external and internal training/competition loads among elite rhythmic gymnasts, along with identifying the corresponding measurements and their responses during monitoring periods. As far as our knowledge extends, this review represents the inaugural attempt at systematically assessing the techniques utilized for gauging training loads in high-performance rhythmic gymnasts. The review's findings underscore a scarcity of research evaluating the efficacy of tools for monitoring external and internal training loads among elite rhythmic gymnasts during the high-performance training phase. The included studies utilized various measurements of external and internal training/competition loads to examine biochemical/hormonal/hematological parameters, recovery, well-being, sleep, and competition anxiety. The scientific papers reviewed in this study exhibited a range of study design, including three interventional [43; 44; 45] and three prospective single cohort studies [41; 42; 46]. Samples comprised both individual and group rhythmic gymnasts, with participant numbers ranging from 8 to 67. The number of training periods assessed varied from one to eight, with all studies focusing on pre-competitive or competitive periods. The most prevalent method for calculating external training load, reported in five [41; 42; 44; 45] of the six papers, was hours per week or minutes per week, consistent with common practice in rhythmic gymnastics [56; 57]. However, some papers lacked detailed information on exercise volume without specifying intensity and training characteristics. Notably, two studies [44; 46], encompassing one day of two training sessions, and 37 weeks, respectively, provided detailed training characteristics, including exercise modalities and duration and the second of the mentioned studies [46] showed differentiation of modality and duration of exercises across analyzed training periods. Only one study measured the ACWR using rolling averages to compare current training load:acute load in relation to longer-term training load:chronic load [58] across a 43-week pre-Olympic Season [41]. This analysis revealed substantial increases during two competition periods and a moderate decrease during transitional period, with an average value of 1.09 \(\pm\) 0.52 across seasons, reaching its peak during 34 th week (training period: Competitive 3, ACWR = 2.69 \(\pm\) 0.25). A value of ACWR \(\geq\) 1.5 is considered one of the factors related to the risk of injury [59] and occurred 55 times during the pre-Olympic Season in the elite group of gymnasts. Other external training load measurements included the execution of competitive routines under competition conditions (\"Kalamata 2010 Rhythmic Gymnastics World Cup\"), as observed in one study [44] assessing short-term intensive anaerobic exercise, judged based on difficulty and execution quality [60]. Studies examining elite rhythmic gymnasts during competition regarding load are scarce, yet they offer insights into athletes' responses to intense training demands throughout the season and how they manage competition pressures [61]. Reviewed literature presented the results of both \"objective\" and \"subjective\" methods applied to measure internal training load with dominance observed in the frequency of use of subjective methods (1/6 studies and 4/6 studies, respectively; one study [43] used methods from both categories). Among the objective methods employed for internal training load measurements, two studies utilized biochemical/hormonal/hematological assessments. Saliva samples were collected to examine the chronic and acute effects of exercise on salivary adiponectin, resistin, and visfatin levels, along with their association and interaction with salivary cortisol and insulin levels.