Reliability of My Jump 2 Derived from Crouching and Standing Observation Heights

The validity and reliability of the My Jump 2 app for measuring vertical stiffness in male college players

Background

Vertical stiffness (Kvert) can be used to evaluate sports performance and injury risk in players. The My Jump 2 smartphone application (App), is increasingly being used by researchers, coaches, and players in the competitive sports field. We aimed to analyze the reliability and concurrent validity of the My Jump 2 app for measuring Kvert in male college players.

Methods

Twenty male college players (10 soccer players, 10 basketball players; age, 20.2 ± 1.3 years old; weight, 76.4 ± 6.0 kg; height, 178.3 ± 4.7 cm) volunteered to take part in this study. Three drop jumps were performed by participants from 30 cm to 40 cm on a force platform and retested after three days. All the jumps were recorded by both the Force platform and the My Jump 2 app. Data obtained from the above two devices were compared using the paired t tests, intraclass correlation coefficient (ICC), coefficient of variation (CV), Pearson product moment correlation coefficient (r), Bland-Altman plots, and one-way regression.

Results

There was almost perfect agreement between measurement instruments for the Kvert value (ICC > 0.972, 95% CI = 0.954-0.992, P < 0.01). Almost perfect agreement was observed between evaluators (ICC > 0.989, 95% CI = 0.981-0.997, P < 0.05). Also, the My Jump 2 app showed excellent intra-rater reliability in all participants (ICC = 1.000, 95% CI = 1.000-1.000, P < 0.001). The My Jump 2 showed good variability when measuring Kvert at T1 30 cm (CV = 5.4%), T1 40 cm (CV = 6.7%), T2 30 cm (CV = 5.0%), and T2 40 cm (CV = 10.3%). The test-retest reliability of My Jump 2 was moderate to good at 30 cm (ICC = 0.708, 95% CI = 0.509-0.827); however, it was lower to moderate at 40 cm (ICC = 0.445, 95% CI = 0.222-0.625). Very large correlations were observed between the force platform and the My Jump 2 for Kvert (r > 0.9655, P < 0.001).

Conclusion

The My Jump 2 smartphone application showed excellent reliability and intra-rater consistency in measuring Kvert in male college players. While demonstrating excellent intra-rater consistency and strong agreement with force platform measurements, it showed slightly lower reliability at higher jump heights. Overall, the My Jump 2 app is a valid tool for evaluating Kvert in college players with careful consideration of its limitations, particularly at higher jump heights.

Validity and reliability of My Jump 2® app to measure the vertical jump on elite women beach volleyball players

Purpose

The aim of this study was to assess the reliability and validity of the My Jump 2® app in measuring jump height, flight time, and peak power among elite women beach volleyball players on sand surfaces.

Methods

Eleven elite female beach volleyball players (aged 23.6 ± 6.2 years; weight 66.3 ± 5.8 kg; height 174.4 ± 5.8 cm; with 8.4 ± 4.8 years of professional experience) participated in this study. Each player performed six countermovement jumps in a wooden box filled with sand on a force platform while simultaneously recording a video for subsequent analysis using the My Jump 2® app.

Results

We found excellent agreement for flight time, jump height and peak power between observers (ICC = 0.92, 0.91 and 0.97, respectively). No significant differences between force platform and My Jump 2® app were detected in the values obtained for the three variables (P > 0.05). For the force platform and the My Jump 2® app, we found a good agreement measuring jump height and flight time (ICC = 0.85 and 0.85, respectively). However, we only found a moderate agreement for peak power (ICC = 0.64). The difference in jump height showed a limit of agreement between -4.10 and 4.74 cm in Bland-Altman, indicating a high level of agreement between the two measurement tools.

Conclusion

Based on our findings, the My Jump 2® app reveals a valid tool for measuring jump height and flight time of CMJ on sand surfaces. However, more caution is needed when measuring peak power.

Validity and reliability of "My Jump app" to assess vertical jump performance: a meta-analytic review

This systematic review and meta-analysis aims to investigate the validity and reliability of the My Jump smartphone application in measuring vertical jump height, specifically using flight-time-based measures. To identify potential studies for inclusion, a comprehensive search strategy was employed in PubMed, Web of Science, Scopus, and EBSCO host databases. Validity was assessed in two ways: (1) mean and standard deviations of My Jump measurements were compared to criterion methods to assess the agreement of raw scores; (2) correlation coefficients evaluated the within-group consistency of rankings between My Jump and criterion methods. Reliability was assessed using intraclass correlation coefficients (ICC). Heterogeneity was evaluated via Cochrane's Q statistic, its p-value, I2 value, and tau2 value. Publication bias was explored through funnel plot symmetry and confirmed with extended Egger's test. Following the search, 21 studies met the inclusion criteria. Results showed no significant difference in raw scores between My Jump and criterion methods, indicating high agreement. High correlation was also found for within-group rankings, suggesting consistency. The My Jump application demonstrated nearly perfect reliability scores. The My Jump application appears to be a valid and reliable tool for sports scientists and strength and conditioning practitioners, offering a cost-effective and accessible means for accurately assessing vertical jump performance in various settings. However, it should be noted that these results are specific to flight-time-based measures, and further research is needed to validate these findings against gold-standard take-off velocity methods.

Reliability of ADR Jumping Photocell: Comparison of Beam Cut at Forefoot and Midfoot

The ability to detect small changes in a vertical jump is crucial when data are used by sports science specialists to monitor their athletes. This study aimed to analyze the intrasession reliability of the ADR jumping photocell and the reliability relative to the position of the transmitter when it is located facing the phalanges of the foot (forefoot) or the metatarsal area (midfoot). A total of 12 female volleyball players performed 240 countermovement jumps (CMJ), alternating both methods. The intersession reliability was higher for the forefoot method (ICC = 0.96; CCC = 0.95; SEM = 1.15 cm; CV = 4.11%) than for the midfoot method (ICC = 0.85; CCC = 0.81; SEM = 3.68 cm; CV = 8.75%). Similarly, the sensitivity values were better for the forefoot method (SWC = 0.32) than for the midfoot method (SWC = 1.04). Significant differences were found between the methods (13.5 cm, p < 0.05, ES = 2.1) with low agreement (rs = 0.57; ICC = 0.49; CCC = 0.15; SEM = 4.7 cm) and heteroscedasticity was observed (r2 > 0.1). In conclusion, the ADR jumping photocell is shown to be a reliable tool for measuring CMJs. However, the reliability of the instrument can be influenced depending on the placement of the device. Comparing the two methods, the midfoot placement was less reliable as indicated by higher values of SEM and systematic error, and thus its use is not recommended.