## 1 Introduction
The ability to perform and recover from such efforts is a key performance indicator [26], with elite-level performance strongly associated with rapid changes in speed and direction, high-intensity displacements, and jumping actions [2; 3; 8; 27]. Accurate assessment of these variables not only enhances performance monitoring but also contributes to injury prevention strategies [27; 28]. Quantifying high-intensity actions during training and competition is critical for prescribing appropriate training loads [16]. However, methodological improvements are needed to establish individualized thresholds that account for contextual factors such as competitive level, gender, and biological maturation--particularly in youth populations [11]. Basketball is also an intermittent impact sport, characterized by frequent physical contact during actions such as rebounds, screens, and defensive plays, especially under high-level opposition [3; 15]. Players positioned closer to the basket experience more frequent impacts and perform more jumps per minute [29]. As such, neuromuscular preparation should include quantification of contact load and impact intensity, tailored to the competitive context and developmental stage of youth athletes. Kinematic load represents the intensity and nature of movement demands placed on athletes and can be quantified using localization technologies. These systems capture key performance variables such as acceleration, deceleration, speed, player load, impactsand high impacts (HI) [20], typically measured in meters per second squared (m/s\({}^{2}\)) through ultra-wide band (UWB) positioning embedded in wearable devices [20]. Inertial measurement units (IMUs), which combine accelerometry and positional tracking, have become increasingly prevalent in sports science applications [20; 30]. These devices enable both real-time and retrospective analysis of physical performance, supporting training load management, recovery strategies, and performance optimization [2; 4; 8; 15; 27; 30; 31; 32]. In basketball, microtechnology has significantly enhanced the precision of external load monitoring, particularly in capturing acceleration and deceleration patterns, offering deeper insights into athletes' physical responses across various competitive contexts [33]. The availability of reference data is fundamental for the accurate analysis of external load in basketball players [12]. It enables coaches and researchers to benchmark individual performance against established standards [34], identify areas for improvement, and adjust training programs accordingly [35]. Reference values also play a critical role in validating new observational methodologies and technologies, ensuring measurement reliability and accuracy [20; 36]. Their integration into training practices contributes to performance optimization and injury prevention [28; 37; 38], particularly in youth athletes, where benchmarks support progression to higher levels of competition by guiding skill development and talent identification [12; 39]. Objective and measurable performance indicators further assist coaches in preparing young athletes for the physical and technical demands of elite basketball [11; 40]. Few studies have quantified external and internal loads in youth sports [14; 22; 41]. In response, the present study profiles the external demands of U14 male basketball using inertial sensors to capture acceleration, deceleration, speed, player load, impacts, and HI. These data were used to generate representative intensity intervals that reflect competitive demands and provide context-specific, individualized benchmarks. The primary objective is to enhance the understanding of external load profiles in youth basketball through the application of inertial devices, which offer valuable insights into the contextualization and individualization of physical demands. This evidence can inform training design and monitoring practices while identifying performance patterns critical for athletic development and injury prevention in young players [28; 38].