## 1 Introduction  
In team sports, the training process can be described as the organized and periodized approach of applying stress or fatigue and recovery, with the purpose of inducing positive changes in technical and tactical skills, physical capacities (e.g., strength or endurance), and the health (i.e., injury-free) status of the players [1, 2, 3]. Indeed, some researcherssuggest that we should consider the training process as a dose-response binomial that produces adaptations in the player, like in other biomedical sciences such as medicine or pharmacology [4; 5]. Therefore, a deep understanding of training load, match load, and post-match recovery status provides numerous advantages to high-performance teams. It (1) improves comprehension of the fatigue and recovery process [2], (2) optimizes the planning process to maximize performance, mitigate injury risk, and, ultimately, increase player availability [1], and (3) avoids a steady state of chronic fatigue, overreaching, and overtraining [6]. In addition, in handball and various team sports, in-season load monitoring enables coaches and practitioners to adjust and periodize the training load each week. This approach helps in stress and recovery management and enables the design of physical training strategies within the microcycle according to player appearance in the game (starter vs. non-starter) [7; 8]. Currently, there is strong unanimity in the scientific community that load is composed of two elements: the external load and the internal load [3; 9]. External load refers to the physical activities completed by players (i.e., the stimulus applied) during training and competition that are quantifiable using international system units (e.g., meters or seconds) [2; 10; 11], whereas internal load represents the individual psycho-physiological reactions to the external load that can be measured with objective (e.g., heart rate or blood lactate) and subjective indicators (e.g., rate of perceived exertion or well-being responses) [2; 10; 11]. However, as many researchers indicate, the same external load could result in considerably different internal loads in each player due to a combination of various intrinsic (e.g., chronological age or genetics) and extrinsic factors (e.g., previous training level) [9; 12]. Consequently, the same training stimulus (i.e., external load) may be appropriate for one player but inappropriate (either significantly higher or lower) for another [11; 12]. Hence, it is essential to combine objective and subjective internal load indicators with perceived well-being to assess the players' capacity to tolerate and recover from the external load experienced during training or competition [9; 12]. In relation to the above-mentioned information, the rate of perceived exertion (RPE) has proven to be a valid and sensitive internal load monitoring tool for handball players due to its high correlation with other objective internal parameters (e.g., heart rate) and external load metrics (e.g., PlayerLoad) [13]. Also, the RPE presents some advantages compared to other objective markers: (1) easy-to-collect; (2) less time-consuming; (3) low-cost; and (4) non-invasive [7; 13]. Additionally, in recent years the use of different objective and subjective tools for monitoring players' fatigue and well-being has become popular among the scientific community and sports practitioners [14]. In particular, the most commonly used tool is the Hooper index, which consists of self-assessment questionnaires about fatigue, stress, muscle soreness, and sleep quality. This index has been used in multiple studies to examine the match-induced fatigue, perceived well-being, and recovery time course of players after a match [10; 15; 16]. However, in handball, external load monitoring has been the most widely used approach to accurately assess match load during official competitions [17]. This is reflected in the few numbers of studies analyzing the internal load and post-match recovery perceptions throughout the microcycle, especially in female handball.