# Validity of the Enode Sensor and My Jump 3 App for Assessing Countermovement Jump Performance
###### Abstract  
Countermovement jump (CMJ) performance analysis is vital in sports science for assessing lower-body strength and neuromuscular efficiency. This study evaluated the validity of the Enode Sensor and My Jump 3 App for measuring vertical jump heights, comparing them to those measured using the established Force Plate. Twenty-nine participants performed CMJs measured using each device. Descriptive statistics indicated mean jump heights of 48.4 \(\pm\) 4.18 cm (for the Enode Sensor), 47.3 \(\pm\) 4.05 cm (for My Jump 3), and 46.1 \(\pm\) 4.03 cm (for the Force Plate). Reliability was confirmed via Intraclass Correlation Coefficients (ICCs), with the Enode Sensor at 0.914 and My Jump 3 at 0.968, demonstrating excellent reliability. Bland-Altman analysis showed mean biases of 2.281 cm (for the Enode Sensor) and 1.297 cm (for My Jump 3) against the Force Plate, with limits of agreement suggesting close alignment. Strong positive correlations were observed (for the Enode Sensor, r = 0.972 and for My Jump 3, r = 0.987; \(p<\) 0.001), and linear regression analysis produced R\({}^{2}\) values of 0.945 and 0.973, respectively, confirming both tools' accuracy for vertical jump measurement. These findings indicate that although both tools are suitable for CMJ assessment, My Jump 3 demonstrated slightly superior accuracy, underscoring the potential for accessible, reliable performance monitoring in sports contexts. CMJ; explosive lower-body power test; measurement accuracy; wearables; video-based assessment tool; force platform; elite-level team athletes; consistency; athletic output; vertical displacement +
Footnote †: journal: applied sciences  
neuromuscular function and jumping ability. Similarly, [PERSON] [7] emphasized the importance of consistent pre-test protocols for accurate CMJ results, highlighting a strong association between pre- and post-warmup CMJ performance in basketball players. Additionally, research on the interaction between the human body and surfaces of varying stiffness, such as that by [PERSON] et al. [7], reveals that softer surfaces can enhance jump performance by increasing the ratio of the positive-to-negative mechanical work, with adjustments influenced by both surface stiffness and movement intensity. Moreover, studies show that short-duration static stretching may not significantly affect jump performance or alter neuromuscular parameters, such as the maximum voluntary contraction, strain, or stiffness [8], underscoring the complexity of factors that impact CMJ performance and its broader applicability in sports assessment. CMJ assessments can derive numerous kinetic and kinematic variables--including jump height, peak power, the rate of force development, and peak velocity--offering comprehensive insights into an athlete's explosive capabilities and overall neuromuscular health [9; 10]. [PERSON] et al. [1] further validated CMJ height as a reliable measure for tracking neuromuscular status in athletes, underscoring its relevance for monitoring fatigue and recovery. Traditional CMJ measurement methods, such as Force Platforms and motion capture systems, are often viewed as gold standards because of their precision in capturing ground reaction forces and detailed kinematic data [11]. Force Platforms, for instance, accurately quantify jump metrics, like vertical jump height, peak force, and the rate of force development [12]. Despite their accuracy, these tools are often expensive, require extensive setup, and are typically confined to laboratory settings, limiting their practicality in routine field assessments [1; 13]. Recent technological advancements have aimed to address these limitations by introducing more accessible alternatives, notably, wearable sensors and mobile applications [14]. Devices like the Enode Sensor leverage accelerometers and gyroscopes to capture motion data during jumps, offering a portable and cost-effective option for performance monitoring [15].