# Validity of the Enode Sensor and My Jump 3 App for Assessing Countermovement Jump Performance
## 3 Results  
The descriptive statistics for vertical jump heights measured using the Enode Sensor, My Jump 3, and Force Plate are presented in Table 1. The Enode Sensor recorded the highest mean vertical jump height (48.4 cm), followed by My Jump 3 (47.3 cm), with the Force Plate recording the lowest mean vertical jump height (46.1 cm). The results, presented in Tables 2 and 3, provide ICC values for both Single Measures and Average Measures, along with their respective 95% Confidence Intervals (CIs) and Significance Levels. Both the Enode Sensor and My Jump 3 demonstrated excellent reliability when compared to the Force Plate, with ICC values of 0.914 and 0.968, respectively, both of which were statistically significant (\(p<0.001\)). The Bland-Altman analysis was conducted to evaluate the agreement between the Enode Sensor and My Jump 3 against the Force Plate in measuring vertical jump heights. The mean bias and limits of agreement for each comparison are presented in Tables 4 and 5, with the corresponding scatterplots in Figures 1 and 2. The results indicated that both the Enode Sensor and My Jump 3 tend to overestimate vertical jump heights compared to the Force Plate. Specifically, in comparing the Enode Sensor to the Force Plate, the mean bias was 2.281 cm, indicating that the Enode Sensor generally overestimated vertical jump heights by 2.281 cm relative to the Force Plate. The limits of agreement ranged from \(-0.281\) cm to 4.84 cm, suggesting some variability in individual measurements. Figure 1: Bland–Altman scatterplot: Enode Sensor vs. Force Plate. Notes: Green Area (Upper Limit of Agreement): Indicates the upper bound of the agreement interval. Purple Area (Mean Difference): Represents the average difference between the two methods, showing any systematic bias. Red Area (Lower Limit of Agreement): Indicates the lower bound of the agreement interval. Points within these limits demonstrate consistency between the methods, while outliers highlight discrepancies. Figure 2: Bland–Altman scatterplot: My Jump 3 vs. Force Plate. Notes: Green Area (Upper Limit of Agreement): Indicates the upper bound of the agreement interval. Purple Area (Mean Difference): Represents the average difference between the two methods, showing any systematic bias. Red Area (Lower Limit of Agreement): Indicates the lower bound of the agreement interval. Points within these limits demonstrate consistency between the methods, while outliers highlight discrepancies. \begin{table}
\begin{tabular}{l c c c} \hline \hline  & \multicolumn{3}{c}{**95\% Confidence Interval**} \\ \cline{2-4}
**Bland–Altman** & **Estimate** & **Lower** & **Upper** \\ \hline Bias (\(n=29\)) & 1.2968 & 1.042 & 1.551 \\ Lower limit of agreement & \(-0.0141\) & \(-0.454\) & 0.426 \\ Upper limit of agreement & 2.6077 & 2.168 & 3.048 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Bland–Altman analysis: My Jump 3 vs. Force Plate. For My Jump 3 versus the Force Plate, the mean bias was 1.297 cm, with My Jump 3 overestimating jump heights by 1.297 cm on average. The limits of agreement, ranging from \(-\)0.014 cm to 3.048 cm, suggest that My Jump 3 is closer to the Force Plate's measurements, indicating better agreement with the Force Plate compared to the Enode Sensor. The correlation analysis (Table 6) between the Enode Sensor and the Force Plate revealed an extremely strong positive relationship (Figure 3), with a Pearson correlation coefficient of 0.972 and a Spearman correlation coefficient of 0.977. Similarly, the My Jump 3 App demonstrated a very strong positive relationship with the Force Plate (Figure 4), showing a Pearson correlation coefficient of 0.987 and a Spearman correlation coefficient of 0.988. These results underscore the high levels of agreement between both the Enode Sensor and My Jump 3 App with the Force Plate, supporting their use as reliable alternatives for measuring vertical jump heights.