## 3 Results
### Reliability  
The reliability of the CMJ MyJump measurements was assessed using the intraclass correlation coefficient (ICC) and measures of variability. The coefficient of variation (CV%) was calculated at 2.2%, indicating low measurement variability. Additionally, the standard error of measurement (SEM) was 0.8154, while the standard error of the estimate (SEE) and the standard error of prediction (SEP) were 1.1385 and 1.6208, respectively. Moreover, for the CMJ, the minimum detectable change (MDC) was determined to assess the smallest within-subject change that can be interpreted as a true performance difference, exceeding the threshold of measurement error. Based on the standard error of measurement (SEM = 0.8154 cm), the MDC was calculated as 2.26 cm, indicating the minimum change required to be considered real and not attributable to measurement variability. The ICC values confirmed the high reliability of the MyJump application for CMJ measurements (Table 8 and Figure 9). The one-way random model for absolute agreement (ICC1) yielded an ICC of 0.974 (95% CI: 0.946-0.988). The two-way random model for absolute agreement (ICC2) produced an identical ICC of 0.974 (95% CI: 0.946-0.988), suggesting  
Figure 8: Scatter plot with regression line: SJ MyJump vs. Chronojump. The black regression line represents the linear relationship between the two measurement methods, while the shaded area indicates the 95% confidence interval. strong reliability across trials. Furthermore, the two-way fixed model for consistency (ICC3) also reported an ICC of 0.974 (95% CI: 0.946-0.988). When analyzing average agreement, the one-way random model (ICC1k) and the two-way random model (ICC2k) produced ICC values of 0.987 (95% CI: 0.973-0.994), while the two-way fixed model (ICC3k) returned a nearly identical value of 0.987 (95% CI: 0.972-0.994). These findings indicated excellent intra-rater reliability, suggesting that the MyJump application provided consistent and repeatable CMJ measurements across trials, and the low SEM and SEE values reinforced the precision of the measurements, demonstrating that systematic error was minimal. The reliability of the SJ MyJump measurements was also assessed using intraclass correlation coefficients (ICCs) and measures of variability. The coefficient of variation (CV%) was 1.33%, indicating low measurement variability. Additionally, the standard error of measurement (SEM) was 0.4721, while the standard error of the estimate (SEE) and the standard error of prediction (SEP) were 0.6594 and 0.9386, respectively. For the SJ, the MDC was computed as 1.31 cm, indicating the minimum change required in squat jump performance to be considered meaningful beyond inherent variability. The ICC values confirmed the high reliability of the MyJump application for SJ measurements (Table 9 and Figure 10). The one-way random model for absolute agreement \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Model** & **Measures** & **Type** & **ICC** & **Lower CI** & **Upper CI** \\ \hline one-way random & Agreement & ICC1 & 0.974 & 0.946 & 0.988 \\ two-way random & Agreement & ICC2 & 0.974 & 0.946 & 0.988 \\ two-way fixed & Consistency & ICC3 & 0.974 & 0.946 & 0.988 \\ one-way random & Avg. Agreement & ICC1k & 0.987 & 0.973 & 0.994 \\ two-way random & Avg. Agreement & ICC2k & 0.987 & 0.973 & 0.994 \\ two-way fixed & Avg. Consistency & ICC3k & 0.987 & 0.972 & 0.994 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Intraclass correlation coefficients for reliability analysis of CMJ measurements. Figure 9: Reliability assessment of CMJ measurements using MyJump: initial vs. retest. Each color represents a unique participant and is used consistently across test and retest sessions to visually link paired observations, only for identification and not for categorical grouping. (ICC1) yielded an ICC of 0.974 (95% CI: 0.946-0.987), indicating strong consistency between test and retest values.