## 4 Discussion
However, it is important to note that while force plates perform as gold standards for capturing jump height, as well as other kinetic variables such as force and power, MyJump focuses primarily on jump height assessment. Complementing these findings, additional research has shown that MyJump 2 demonstrates very large correlations with OptoJump as well, for both CMJ and SJ (\(r\) = 0.97) [17], and that frame rates at or above 240 Hz are sufficient to ensure accuracy in video-based jump height estimations [18]. Moreover, studies validating MyJump Lab, a newer version of the app, confirmed its near-perfect correlation with force plates (\(r\) = 0.968) and high intra-session reliability (SEM = 0.43 cm, CV = 1.23%) [19]. Finally, [PERSON] et al. [20] reported strong concurrent validity and inter-rater reliability (ICC > 0.9) for both CMJ and SJ measurements, further confirming the application's suitability for both research and applied sports science contexts. In this context, it is worth noting that vertical jump assessments have also been used to evaluate inter-limb asymmetries in athletes [13; 21], given the sport's fundamentally unilateral movement patterns that often favor one dominant limb. Such asymmetries have been associated with reduced athletic performance and elevated injury risk, especially in youth soccer populations [41]. Previous studies have demonstrated significant relationships between jump asymmetry and performance in sprinting [42], change of direction ability [43] and overall fitness metrics [44; 45; 46], underscoring the importance of reliable jump-based asymmetry assessments in long-term athletic development. Furthermore, research has shown that glyometric training can be effectively adapted for preadolescent soccer athletes [47; 48; 49; 50], highlighting the need for accessible tools like MyJump 2 to monitor adaptations and asymmetries across maturational stages. Although the present study focused on bilateral CMJ and SJ measurements, future research should consider the application of MyJump 2 in single-leg jump tests to assess functional asymmetries and contribute to targeted interventions in youth soccer development programs. Reliability analyses further confirmed the intra-rater consistency of MyJump 2. ICC values for both CMJ and SJ ranged from 0.974 to 0.987 across absolute and average agreement models, exceeding the commonly accepted threshold (ICC > 0.90) for excellent reliability [39]. These findings align with previous research demonstrating the strong test-retest reliability of MyJump 2 and its earlier studies [8; 10]. Notably, the coefficient of variation (CV) for CMJ (2.2%) and SJ (1.33%) was low, and the SEM and SEE valuesremained minimal, further supporting the tool's precision and practical utility in repeated performance monitoring. The consistency observed between the test and retest sessions, as evidenced by Bland-Altman analyses, strengthens the argument for MyJump's suitability in both research and applied contexts. For CMJ, the test-retest bias was only 0.153 cm, while for SJ, it was 0.186 cm. The limits of agreement for both jumps were narrow and symmetrical, reflecting stable performance measurement across time. A key strength of this study lies in its inclusion of a mixed-age sample, encompassing adolescents and junior soccer players under 18. However, the study focused on younger athletes, with the mean age being 16.6 years (95% CI: 15.7-17.4), with a standard deviation of 1.87 years. Future studies could expand the age range to include young adults for a more comprehensive analysis. Previous validation research has typically focused on homogenous age groups--either adults [7] or youth athletes [9; 11]--limiting the generalizability of findings across developmental stages. By addressing this gap, the present study contributes important evidence supporting the applicability of MyJump 2 across a broader range of maturational levels.