## 1 Introduction  
Unlike many other sports that rely on dynamic strength, climbing requires sustained force production in isometric holds, underscoring the importance of grip strength in this discipline. The ability to generate force in the grip is recognized as a key performance factor due to its essential role in supporting body weight and maintaining secure holds [1]. Extensive research has consistently demonstrated that climbers exhibit significantly greater grip strength than non-climbers when assessed with both climbing-specific strength teststhat mimic climbing positions and handgrip strength tests [2; 3; 4; 5; 6; 7; 8; 9; 10], with the magnitude of these differences more pronounced at higher levels of climbing skill [4; 6; 11]. Although some studies have employed handheld dynamometers to assess finger strength in climbers [9; 10], these instruments may lack the specificity needed to accurately measure the finger flexor strength essential for climbing [12; 13]. This limitation may stem from their design, which emphasizes thumb involvement and general hand function rather than replicating the grip types and finger-loading patterns commonly used in climbing. Consequently, they may not fully capture the sport-specific adaptations developed through climbing practice. In addition, studies examining finger flexor strength through various climbing-specific assessments have shown inconsistent results [3; 4; 5; 7]. While some studies describe greater specialized grip strength in climbers [4; 5; 7], other authors report no significant differences between recreational climbers and non-climbers [3]. This discrepancy in results complicates the establishment of clear evidence regarding the extent to which finger flexor isometric strength distinguishes climbers from non-climbers, underscoring the necessity for more precise and specific assessment devices and protocols. Accurate assessment of isometric finger flexor strength in climbers must consider that climbing involves various grip types (such as _open hand_, _drag_, and _half-crimp_), which can significantly impact climbing performance [11; 14; 15; 16]. The three-finger drag grip, involving only the front three fingers (digits II-IV), reduces the impact of variations in the fifth digit's length, which can affect the degree of extension in digits III and IV. This approach helps standardize measurements by minimizing the variability introduced by different hand anthropometrics, thereby allowing for more accurate assessments of open-hand strength specific to the slope grip technique [14]. In contrast, the half-crimp grip, essential for more demanding routes, allows force application up to the distal phalanges and enhances force production through effective engagement of the flexor digitorum profundus and increased activation of intrinsic hand muscles [17; 18]. Although the isometric strength of finger flexors has been frequently studied in climbers and other populations [5; 11; 14; 19; 20; 21], few of these studies report repeatability and reliability values beyond the intraclass correlation coefficient (ICC) [5; 11; 14; 19]. These values have limited practical utility, as the specific procedure used to calculate the ICC is often not specified [5], and most fail to report the standard error of measurement (SEM) or the minimum detectable change (MDC). These variables are essential for interpreting the likelihood of change magnitude as a result of training or for comparisons between populations. In climbing, the ability to support body mass can be a key factor in performance. Therefore, besides muscle strength, body composition has been widely studied in climbers of different skill levels, as well as in comparisons between climbers and non-climbers, with findings indicating that climbers tend to maintain a low body fat percentage [1; 22]. In addition to assessing strength and body composition separately, it is useful to consider muscle quality (MQ), which refers to the ability of a muscle to generate force relative to its mass [23; 24].