Concurrent Validity and Reliability of the Skyhook Jump Mat for Measuring Countermovement and Abalakov Jump

Concurrent Validity and Reliability of the Skyhook Jump Mat for Measuring Countermovement and Abalakov Jump | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Concurrent Validity and Reliability of the Skyhook Jump Mat for Measuring Countermovement and Abalakov Jump Deniz Şentürk, Onur Topuz, Faruk Aktas, Abdulkadir Kutluca, Osman Çoşkun This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8447533/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract This study aimed to examine the concurrent validity of the Skyhook jump mat for measuring countermovement jump (CMJ) and Abalakov jump (AJ) height using a force plate as the criterion reference, and to assess its within-session reliability. Fifty-four trained individuals (17 females, 37 males; mean age 20.9 ± 1.7 years) performed CMJ and AJ trials on both the Skyhook jump mat and a force plate across multiple sessions. Skyhook measurements showed an almost perfect association with the force plate (r = 0.997) for both CMJ and AJ. Measurement errors were low (SEE = 1.87), and SEE values were smaller than the corresponding SWC. Linear mixed-effects models indicated a fixed bias, with the Skyhook consistently overestimating jump height by approximately 1.7 cm (p ≤ 0.001), while showing no proportional bias. Reliability analyses demonstrated excellent consistency across repeated trials (CMJ: CV = 1.45%, ICC(3,1) = 0.973; AJ: CV = 1.43%, ICC(3,1) = 0.997). The Skyhook jump mat slightly and systematically overestimates jump height compared with a force plate but demonstrates excellent validity, reliability, and sufficient sensitivity to detect meaningful changes in performance. These characteristics support its use as a practical and cost-effective tool for monitoring jump performance in applied sports settings. Physical sciences/Engineering Health sciences/Health care vertical jump countermovement jump abalakov jump validity reliability force plate Figures Figure 1 Figure 2 Figure 3 INTRODUCTION The vertical jump (VJ) test is widely used to evaluate an athlete’s power [ 1 ] and fatigue status. It is also known that various performance variables in vertical jump (VJ) tests are highly associated with abilities such as sprint speed [ 2 ] and change of direction ability [ 3 ]. The capacity to generate explosive force during a jump is strongly associated with sport-specific actions [ 5 ], such as sprinting [ 4 ], jumping [ 6 ], and cutting [ 7 ]. These movement patterns are essential for athletic performance in basketball [ 8 ], soccer [ 4 ], and volleyball [ 6 ], where optimal neuromuscular coordination and force production are critical. Accordingly, numerous standardized VJ protocols have been established to evaluate these performance capacities in both research and applied settings. Several VJ protocols, including the Abalakov Jump (AJ), Countermovement Jump (CMJ), Drop Jump, and 10/5 Rebound Jump, are commonly used by coaches to obtain jump height (JH), reactive strength index (RSI), and ground contact time (GCT) values [ 9 – 11 ]. Due to its simplicity, reproducibility, and strong relationship with sport performance, the CMJ has been widely adopted by strength and conditioning coaches and sports scientists, and within this test, JH emerges as the most frequently reported parameter as it provides a valid and direct indicator of lower-limb explosive power [ 12 ]. To measure JH and related variables, numerous devices have been developed, including 3D motion capture systems [ 13 ], force platforms [ 14 ], linear position transducers [ 15 ], contact mats [ 16 ], accelerometers [ 17 ], and mobile applications [ 18 ]. While these devices employ different methodologies, only motion capture systems and force platforms are considered the “gold standard,” as they directly assess center of mass displacement and take-off velocity (TOV) [ 2 , 19 ]. Despite their accuracy, force platforms and 3D motion capture systems are not widely adopted in applied settings due to their high cost and lengthy setup [ 13 ]. In addition, these devices require the payment of a high annual software license fee, which further increases the overall cost and represents a major challenge for their routine use [ 20 ]. These limitations have prompted the search for more practical and portable solutions to assess jump performance in applied settings. Jump mats stand out due to features such as portability, affordability, and user-friendly software. [ 21 ]. They allow rapid acquisition of JH which has increased their appeal among sports scientists and coaches [ 22 ]. Notably, the Skyhook (RDM Innovation, Largo, Florida) includes integrated software with data storage, enabling more effective monitoring of training sessions. In addition, the Skyhook mat’s free software increases its accessibility for coaches and practitioners. However, all jump mats estimate JH using the time-in-air (TIA) method, and outcomes may vary depending on calculation equations and hardware properties, such as micro-switch sensitivity and efficiency [ 21 ]. In summary, jump mats that rely on the TIA method represent a practical alternative to more complex laboratory-based systems [ 23 ]. Nevertheless, independent studies are required to establish the validity and reliability of each device before they can be confidently implemented in practice [ 24 ]. Therefore, the primary aim of the present study was to evaluate the concurrent validity of the Skyhook mat for assessing CMJ and AJ jump height, using a force plate as the criterion reference. A secondary aim was to evaluate the within-session reliability of the Skyhook mat, thereby determining its consistency as a field-based measurement tool. METHODS Experimental approach to the problem A concurrent measurement design was applied to investigate the accuracy of the Skyhook jump mat in assessing jump height compared with a force platform as the criterion reference. In addition to examining concurrent validity, the study also aimed to evaluate the within-session reliability of the Skyhook by analyzing potential differences across repeated trials. The study protocol included one familiarization session followed by two experimental sessions. During each experimental session, subjects performed five CMJ and five AJ trials in a randomized order. In all testing sessions, CMJ and AJ were performed simultaneously on the force platform and the Skyhook mat to allow direct comparison between devices. Furthermore, by recruiting a relatively large sample size, the study sought to determine whether proportional bias exists at different jump heights, thereby providing deeper insights into the performance of the Skyhook across a wide range of outputs. All testing procedures were carried out in the university research laboratory under standardized environmental conditions (temperature 22–24°C, relative humidity ~60%) and supervised by the same researcher (DS). Ethics Approval and consent to participate The study adhered to the Declaration of Helsinki and was approved by the Institutional Ethics Committee of Istanbul Gelisim University (Approval No: 2025/0692). Prior to data collection, all subjects were provided with a detailed verbal explanation of the procedures and signed an informed consent form, confirming their voluntary participation. Subjects Fifty-four recreationally active individuals (17 females and 37 males), with an average age of 20.9 years (standard deviation [SD]: 1.7 years; range: 20–36 years), voluntarily enrolled in this study. The subjects exhibited a mean body mass of 73.3 kg (SD: 16.4 kg) and a body height of 175.2 cm (SD: 7.5 cm). All subjects had previous plyometric training experience and demonstrated proper technique during the familiarization session. Note that all subjects regularly performed VJ exercise, as part of their RT programs. None of the subjects had any physical limitations or neuromuscular injuries that could interfere with safe participation in the study. Subjects were instructed to refrain from strenuous lower-body exercise throughout the experimental period and to arrive at each testing session in a rested state. Procedures Familiarization session (session 1) The familiarization session commenced with a detailed explanation of the study protocol and the procedures to be followed. Subjects were thoroughly briefed on the CMJ and AJ protocols, including their proper execution. Individuals who agreed to participate provided written informed consent before being formally enrolled in the study. Anthropometric assessments, including height and body mass, were subsequently recorded. Following this, subjects completed a standardized general warm-up consisting of light jogging and dynamic joint mobilization. This was followed by bodyweight CMJs and AJ performed at approximately 70%, 80%, 90%, and 100% of each subject’s perceived maximal effort as a jump-specific warm-up. After the warm-up routines, subjects executed five CMJ and five AJ trials on both the force platform and the Skyhook mat to become accustomed to the simultaneous measurement procedure. Subjects were instructed to perform all jumps with maximal effort and proper technique. All subjects were already familiar with VJ based movements as part of their regular training routines, and this session ensured they could perform the tasks with correct execution and consistency. Subjects who failed to demonstrate technical proficiency were excluded from further study participation. Experimental protocol (sessions 2-3) Following the warm-up, which was identical to the routines performed during the familiarization session, subjects were positioned on the Skyhook mat placed directly on top of the force platform (ForceDecks, FDLite V.2, VALD, Brisbane, Australia). Before initiating each set of jumps, they were instructed to stand motionless until their body weight was accurately recorded by the software [25]. The CMJ protocol required subjects to start from an upright standing position, with a straight torso, fully extended knees, and feet shoulder-width apart. After the countdown signal “3, 2, 1, go,” subjects performed a rapid countermovement to a self-selected depth, immediately followed by an explosive upward motion to maximize jump height [26]. For the AJ trials, the protocol was identical to the CMJ, except that subjects were allowed free arm movement to enhance jump performance [27]. In all trials, subjects were verbally encouraged to move as vertically as possible and achieve maximal jump height. Subjects began the experimental sessions in a randomized order, starting either with CMJ or AJ. A one-minute rest interval was provided between five consecutive jumps, and a five-minute passive recovery period was given between the two protocols. Measurement equipment and data analysis The temporal occurrence of all jumps was recorded concurrently by means of a jump mat (Skyhook, RDM Innovation, Largo, Florida, USA) positioned directly on top of a portable force platform (FDLite ForceDecks dual force platforms; VALD, Brisbane, Australia). The corners of the force plate’s protective foam cover were marked with white tape in a cross pattern to ensure that the Skyhook device could be precisely centered. The Skyhook was then positioned directly over these markings, aligning perfectly with the middle of the force plate. In addition, a rectangular frame was drawn with white tape on top of the Skyhook, corresponding to the two individual plates of the force platform, to ensure that subjects performed their jumps with both feet placed correctly on the force plates (see Figure 1). The Skyhook device was connected to its proprietary mobile software (version 3.4.4), which is compatible with iOS. This software enables the real-time acquisition of jump height values. Jump height from both the Skyhook mat and the force plate was calculated using the flight-time method, while the force plate simultaneously measured vertical ground reaction forces at a sampling frequency of 1000 Hz [28]. Both systems were firmly fixed to the ground and synchronized to ensure concurrent data collection during all CMJ and AJ. Successful jump attempts captured by the Skyhook were automatically transferred in real time to Microsoft Excel, thereby enabling immediate data storage, organization, and analysis, while also preventing overlap between concurrently recorded jumps. Statistical analyses Descriptive statistics are presented as mean and standard deviation (SD) for all demographic variables. Pearson product–moment correlation coefficients (r) with 95% confidence intervals (95% CI) were calculated to assess the linear association between the two devices. The coefficient of variation (CV%) and corresponding 95% CI were computed to evaluate the relative variability of Skyhook measurements compared with the criterion force plate values (CV% = [Typical Error / Mean] × 100) [29]. The standard error of the estimate (SEE) was also calculated to provide an index of the prediction error of the regression model between devices. In addition, the smallest worthwhile change (SWC), calculated as 0.2 × SD, was compared with the standard error of estimate (SEE) to determine the device’s sensitivity in detecting meaningful changes in jump performance. The mean absolute error (MAE) and mean absolute percentage error (MAPE) were computed to provide complementary measures of absolute and relative differences between devices. To examine the agreement between the Skyhook and the Force-plate devices, we applied a Linear Mixed-Effects Model (LMM). In this model, device (Skyhook vs. Force plate) was included as a fixed effect, while participant ID was modeled as a random intercept to account for repeated measures within individuals. Model estimates are reported as regression coefficients with 95% CI, and p-values. Within-session reliability was assessed using the CV%, calculated as the standard deviation divided by the mean of repeated trials for each participant, with group mean CV% reported across all subjects [29]. In addition, the typical error of measurement (TE) and intraclass correlation coefficients [ICC(3,1) and ICC(3,k)] were computed to provide complementary indices of absolute and relative reliability [30]. Figures were prepared in JASP (version 0.19.3; Amsterdam, The Netherlands). All statistical analyses were conducted in Python (version 3.11; Python Software Foundation, Wilmington, DE, USA). Statistical significance was set at p ≤ 0.05. Results Concurrent validity analyses demonstrated that both CMJ and AJ values obtained from the Skyhook mat showed an almost perfect association with the criterion force plate (r = 0.997, 95% CI: 0.997–0.998 for both jump types). Measurement errors were low, with SEE values of 1.87 cm for CMJ and 1.90 cm for AJ, and corresponding MAE values of 1.74 cm and 1.76 cm, respectively. MAPE remained around 5% for both jump types (CMJ = 5.72%; AJ = 5.17%). The coefficient of variation (CV) values were well below the 10% threshold, confirming high measurement consistency. Specifically, CV was 1.45% (95% CI: 1.34–1.57) for CMJ and 1.43% (95% CI: 1.31–1.54) for AJ. Importantly, SEE values were smaller than the corresponding SWC (CMJ = 1.92 cm; AJ = 2.29 cm), indicating that the Skyhook mat is sufficiently sensitive to detect small but meaningful changes in jump performance (Table 1). LMM analyses identified a fixed bias, with the Skyhook mat systematically overestimating jump height relative to the force plate by approximately 1.73 cm for CMJ (95% CI: 1.67–1.79 cm, p ≤ 0.001) and 1.74 cm for AJ (95% CI: 1.67–1.80 cm, p ≤ 0.001). However, no proportional bias was detected, as indicated by non-significant regression slopes (CMJ: slope = 0.0016, p = 0.793; AJ: slope = –0.0020, p = 0.698) (Figures 2 and 3). Overall, these results indicate that although the Skyhook mat consistently overestimated jump height by ~1.7 cm compared with the force plate, the device exhibited excellent agreement (r = 0.997) and high validity (CV < 2%) across both CMJ and AJ measurements (Table 1). [Table 1] [Figure 1] [Figure 2] Within-session reliability analyses further confirmed the consistency of Skyhook measurements. CV across repeated trials was 1.45% for CMJ (95% CI: 1.37–1.55) and 1.43% for AJ (95% CI: 1.35–1.52), indicating very low relative variability. TE values were small (1.8 cm for CMJ; 1.9 cm for AJ), corresponding to approximately 2% of the mean jump height. ICC based on a two-way mixed-effects model with absolute agreement also supported excellent reliability, with ICC (3,1) = 0.973 (95% CI: 0.962–0.983) for single measures and ICC (3,k) = 0.970 (95% CI: 0.958–0.981) when repeated trials were averaged. (Table 2). Collectively, these results demonstrate that the Skyhook mat provides highly reliable measurements of jump performance within a single testing session. [Table 2] Discussion This study was designed to examine the concurrent validity of the Skyhook jump mat in measuring CMJ and AJ height relative to a force plate, as well as to assess within-session reliability. These results indicate that although the device consistently overestimates jump height by approximately 1.7 cm as a fixed bias, it remains proportionally consistent across a wide range of jump heights (13.8–68.9 cm). In addition, an almost perfect relationship was observed between the two devices (r = 0.997), accompanied by low measurement error (CMJ: 1.87, AJ: 1.90), low CV (CMJ: 1.45%, AJ: 1.43%), acceptable MAE (CMJ: 1.74, AJ: 1.76), and MAPE (CMJ: 5.72%, AJ: 5.17%). Furthermore, within-session reliability analyses revealed excellent consistency (CMJ: TE = 1.8, CV = 1.45%, ICC = 0.973; AJ: TE = 1.9, CV = 1.43%, ICC = 0.997). Our findings suggest that, despite the presence of a systematic measurement error compared with the force plate, no proportional bias was evident, and the Skyhook mat exhibited nearly perfect reliability across repeated trials. The SWC analysis further indicated that the measurement error of the Skyhook mat (SEE = 1.87 cm for CMJ; 1.90 cm for AJ) was smaller than the smallest worthwhile change (SWC = 1.92 cm for CMJ; 2.29 cm for AJ). These findings suggest that the device is sufficiently sensitive to detect small but meaningful changes in jump performance, reinforcing its practical applicability in athlete monitoring [31]. More importantly, beyond the 2 cm benchmark, the key strength of the Skyhook mat is that its measurement error is approximately constant across the observed range of jump heights and highly consistent across repeated trials. The absence of proportional bias (CMJ slope = 0.0016, p = 0.793; AJ slope = −0.0020, p = 0.698) indicates that the device provides stable estimates across different jump heights, supporting its applicability in athlete groups with varying performance levels. At the same time, the very low within-session variability demonstrates near perfect within-repetition repeatability. Consequently, when the Skyhook is used consistently, observed changes are unlikely to be driven by random fluctuation across trials, which reinforces the utility of the Skyhook for session-to-session monitoring. A number of studies have previously examined the concurrent validity of devices using the flight-time method [23] against gold-standard laboratory systems, such as force plates [21] and motion capture [32]. Research conducted in comparison with force plates has consistently demonstrated that jump mats tend to report higher values than criterion measures for both CMJ and squat jumps, with overestimations of approximately 1-3 cm [19, 33, 34]. These discrepancies can be attributed to the divergent methodologies employed by the two systems. While both systems estimate jump height using the flight-time method, force plates calculate flight time based on vertical ground reaction forces recorded with high-frequency sensors (ranging from 1000 Hz to 10 000 Hz) [35]. In contrast, jump mats rely on pressure-sensitive sensors that only detect foot contact events [37]. It appears that, depending on the sampling frequency, these differences in event detection can cause a small increase in flight time, leading to a systematic overestimation of jump height. [36]. As indicated by the findings of studies employing two-dimensional and three-dimensional motion capture systems, analogous inconsistencies have also been observed [37, 38]. The discrepancies observed have been ascribed primarily to variations in ankle positioning during take-off and landing [37]. Furthermore, extant research has indicated that variations in jump height estimation may also be influenced by factors such as footwear and surface characteristics [39], device sampling frequency, and embedded software algorithms [38]. This systematic bias may be primarily explained by differences in sensor technology, as force plates detect flight time through high-frequency ground reaction force signals, whereas jump mats rely on pressure-sensitive switches that are more prone to slight delays in event detection [16]. Reflecting these methodological differences and contextual influences, the present study demonstrated that the Skyhook mat consistently overestimated jump height by around 1.7 cm for both CMJ and AJ jumps. Our findings demonstrate that the Skyhook jump mat slightly and systematically overestimates jump height compared with a force plate, while not introducing any proportional bias. This systematic difference is likely attributable to several factors discussed above, including sensor characteristics [16], sampling frequency [35], and methodological variations [37]. Future research should aim to further investigate these potential sources of error. It is noteworthy that the TE was smaller than the SWC, indicating that the device is sufficiently sensitive to detect practically meaningful changes in jump performance [40]. Furthermore, the device demonstrated nearly perfect reliability across repeated trials, reinforcing its consistency. Taken together, these results support the use of the Skyhook mat as a practical alternative to laboratory-based systems in sports science research and athlete monitoring. Conclusion In summary, the Skyhook jump mat provides accurate assessments of CMJ and AJ jump heights relative to a force plate, although it consistently shows a small systematic overestimation. The absence of proportional bias ensures that the device can be used reliably across athletes with different performance levels. In addition, its near-perfect trial-to-trial reliability and ability to detect performance changes beyond the standard error of measurement make it a practical option for monitoring athletes’ performance. Moreover, the fact that the device does not require a software license fee represents a major advantage, further enhancing its applicability and sustainability in field settings. Therefore, the Skyhook jump mat can be considered a strong alternative to laboratory-based systems in sports science research and athlete monitoring. Declarations Acknowledgements The authors thank all participants for their time, effort, and commitment throughout the study. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Author contributions D.S. designed the study, collected the data, conducted the statistical analyses, and drafted the manuscript. F.A., O.C., O.T., and A.K. contributed to data interpretation, methodological decisions, and manuscript revisions. All authors reviewed and approved the final version of the manuscript. Competing interests The authors declare no competing interests. Data availability Data are available from the corresponding author upon reasonable request. Code availability Code used for data processing and statistical analyses is available from the corresponding author upon reasonable request. References Kons, R. L., Ache-Dias, J., Detanico, D. & Barth, J. Dal Pupo, J. Is vertical jump height an indicator of athletes' power output in different sport modalities? J. Strength. Cond Res. 32 , 708–715 (2018). Washif, J. A. & Kok, L. Y. Relationships between vertical jump metrics and sprint performance, and qualities that distinguish between faster and slower sprinters. J. Sci. Sport Exerc. 4 , 135–144 (2022). Vescovi, J. D. & McGuigan, M. R. Relationships between sprinting, agility, and jump ability in female athletes. J. Sports Sci. 26 , 97–107 (2008). Wisløff, U., Castagna, C., Helgerud, J., Jones, R. & Hoff, J. Strong correlation of maximal squat strength with sprint performance and vertical jump height in elite soccer players. Br. J. Sports Med. 38 , 285–288 (2004). Sargent, L. W. Some observations on the Sargent test of neuromuscular efficiency. Am. Phys. Educ. Rev. 29 , 47–56 (1924). Barnes, J. L. et al. Relationship of jumping and agility performance in female volleyball athletes. J. Strength. Cond Res. 21 , 1192–1196 (2007). McFarland, I. T., Dawes, J. J., Elder, C. L. & Lockie, R. G. Relationship of two vertical jumping tests to sprint and change of direction speed among male and female collegiate soccer players. Sports (Basel) . 4 , 11 (2016). Shalfawi, S. A., Sabbah, A., Kailani, G., Tønnessen, E. & Enoksen, E. The relationship between running speed and measures of vertical jump in professional basketball players: a field-test approach. J. Strength. Cond Res. 25 , 3088–3092 (2011). Markovic, G., Dizdar, D., Jukic, I. & Cardinale, M. Reliability and factorial validity of squat and countermovement jump tests. J. Strength. Cond Res. 18 , 551–555 (2004). Young, W. A simple method for evaluating the strength qualities of the leg extensor muscles and jumping abilities. Strength. Cond Coach . 2 , 5–8 (1995). Xu, J. et al. A narrative review of rebound jumping and fast stretch-shortening cycle mechanics. Strength. Cond J. 47 , 302–316. https://doi.org/10.1519/SSC.0000000000000878 (2025). Alba-Jiménez, C., Moreno-Doutres, D. & Peña, J. Trends assessing neuromuscular fatigue in team sports: a narrative review. Sports (Basel) . 10 , 33. https://doi.org/10.3390/sports10030033 (2022). Aragón, L. F. Evaluation of four vertical jump tests: methodology, reliability, validity, and accuracy. Meas. Phys. Educ. Exerc. Sci. 4 , 215–228 (2000). Walsh, M. S., Ford, K. R., Bangen, K. J., Myer, G. D. & Hewett, T. E. The validation of a portable force plate for measuring force-time data during jumping and landing tasks. J. Strength. Cond Res. 20 , 730–734. https://doi.org/10.1519/R-18225.1 (2006). Ruiz-Alias, S. A. et al. Validity and reliability of velocity and power measures provided by the Vitruve linear position transducer. PLoS One . 19 , e0312348. https://doi.org/10.1371/journal.pone.0312348 (2024). García-López, J., Morante, J. C., Ogueta-Alday, A. & Rodríguez-Marroyo, J. A. The type of mat (contact vs. photocell) affects vertical jump height estimated from flight time. J. Strength. Cond Res. 27 , 1162–1167. https://doi.org/10.1519/JSC.0b013e31826520d7 (2013). Stanton, R., Doering, T., Macgregor, C., Borges, N. & Del Vecchio, L. Validity of a contact mat and accelerometric system to assess countermovement jump from flight time. Meas. Phys. Educ. Exerc. Sci. 23 , 39–46. https://doi.org/10.1080/1091367X.2018.1493593 (2019). Şentürk, D., Yüksel, O. & Akyildiz, Z. The concurrent validity and reliability of the My Jump Lab smartphone app for the real-time measurement of vertical jump performance. Proc. Inst. Mech. Eng. P J. Sports Eng. Technol. 17543371241246439 (2024). https://doi.org/10.1177/17543371241246439 Buckthorpe, M., Morris, J. & Folland, J. P. Validity of vertical jump measurement devices. J. Sports Sci. 30 , 63–69. https://doi.org/10.1080/02640414.2011.624539 (2012). Merrigan, J. J. et al. Applying force plate technology to inform human performance programming in tactical populations. Appl. Sci. 11 , 6538. https://doi.org/10.3390/app11146538 (2021). Pueo, B., Penichet-Tomás, A. & Jimenez-Olmedo, J. M. Reliability and validity of the Chronojump open-source jump mat system. Biol. Sport . 37 , 255–259. https://doi.org/10.5114/biolsport.2020.95636 (2020). Conde, A., González-Devesa, D., Suárez Iglesias, D. & Ayán, C. The validity and reliability of a portable device (ADR-Jumping) to estimate vertical jump performance. Proc. Inst. Mech. Eng. P J. Sports Eng. Technol. 239, 349–355 (2025). https://doi.org/10.1177/17543371221127079 Xu, J. et al. A systematic review of the different calculation methods for measuring jump height during the countermovement and drop jump tests. Sports Med. 53 , 1055–1072. https://doi.org/10.1007/s40279-023-01828-x (2023). Guppy, S. N. et al. The agreement between a portable contact-mat and force-plates during bilateral vertical jumps. Int. J. Exerc. Sci. 15 , 632–644 (2022). Collings, T. J., Lima, Y. L., Dutaillis, B. & Bourne, M. N. Concurrent validity and test-retest reliability of VALD ForceDecks' strength, balance, and movement assessment tests. J. Sci. Med. Sport . 27 , 572–580. https://doi.org/10.1016/j.jsams.2024.04.014 (2024). Claudino, J. G. et al. The countermovement jump to monitor neuromuscular status: a meta-analysis. J. Sci. Med. Sport . 20 , 397–402. https://doi.org/10.1016/j.jsams.2016.08.011 (2017). Rodríguez-Rosell, D., Mora-Custodio, R., Franco-Márquez, F., Yáñez-García, J. M. & González-Badillo, J. J. Traditional vs. sport-specific vertical jump tests: reliability, validity, and relationship with the legs strength and sprint performance in adult and teen soccer and basketball players. J. Strength. Cond Res. 31 , 196–206. https://doi.org/10.1519/JSC.0000000000001476 (2017). Merrigan, J. J. et al. Countermovement jump force-time curve analyses: reliability and comparability across force plate systems. J. Strength. Cond Res. 38 , 30–37. https://doi.org/10.1519/JSC.0000000000004586 (2024). Hopkins, W. G. Measures of reliability in sports medicine and science. Sports Med. 30 , 1–15. https://doi.org/10.2165/00007256-200030010-00001 (2000). Koo, T. K. & Li, M. Y. A guideline of selecting and reporting intraclass correlation coefficients for reliability research. J. Chiropr. Med. 15 , 155–163. https://doi.org/10.1016/j.jcm.2016.02.012 (2016). Batterham, A. M. & Hopkins, W. G. Making meaningful inferences about magnitudes. Int. J. Sports Physiol. Perform. 1 , 50–57 (2006). Pueo, B., Lipinska, P., Jiménez-Olmedo, J. M., Zmijewski, P. & Hopkins, W. G. Accuracy of jump-mat systems for measuring jump height. Int. J. Sports Physiol. Perform. 12 , 959–963. https://doi.org/10.1123/ijspp.2016-0511 (2017). Kenny, I. C., Cairealláin, Ó., Comyns, T. M. & A. & Validation of an electronic jump mat to assess stretch-shortening cycle function. J. Strength. Cond Res. 26 , 1601–1608. https://doi.org/10.1519/JSC.0b013e318234ebb8 (2012). Enoksen, E., Tønnessen, E. & Shalfawi, S. Validity and reliability of the Newtest Powertimer 300-series testing system. J. Sports Sci. 27 , 77–84 (2009). Raymond, F. et al. Using portable force plates to assess vertical jump performance: a metrological appraisal. Sports (Basel) . 6 , 149. https://doi.org/10.3390/sports6040149 (2018). Whitmer, T. D. et al. Accuracy of a vertical jump contact mat for determining jump height and flight time. J. Strength. Cond Res. 29 , 877–881 (2015). Sorenson, B., Kernozek, T. W., Willson, J. D., Ragan, R. & Hove, J. Two- and three-dimensional relationships between knee and hip kinematic motion analysis: single-leg drop-jump landings. J. Sport Rehabil . 24 , 363–372. https://doi.org/10.1123/jsr.2014-0206 (2015). Schümperlin, D., Schärer, C., Kalberer, L., Ferguson, S. J. & Lorenzetti, S. R. Pilot study: validity and reliability of textile insoles used to measure the characteristics of landing tasks during rehabilitation and artistic gymnastics. BMC Res. Notes . 16 , 59 (2023). Malisoux, L., Gette, P., Urhausen, A., Bomfim, J. & Theisen, D. Influence of sports flooring and shoes on impact forces and performance during jump tasks. PLoS One . 12 , e0186297. https://doi.org/10.1371/journal.pone.0186297 (2017). Weakley, J. et al. Testing and profiling athletes: recommendations for test selection, implementation, and maximizing information. Strength. Cond J. 46 , 159–179. https://doi.org/10.1519/SSC.0000000000000784 (2024). Tables Table 1 . Concurrent validity and measurement bias of the Skyhook mat in comparison with the force plate Variable r (95% CI) SEE (cm) SWC MAE (cm) MAPE (%) CV 95% CI Fixed bias (cm) 95% CI Fixed bias p Proportional bias (slope) Proportional bias p CMJ 0.997 [0.997–0.998] 1.87 1.92 1.74 5.72 1.45 [1.34–1.57] 1.73 [1.67–1.79] p ≤ 0.001 0.0016 0.793 AJ 0.997 [0.997–0.998] 1.90 2.29 1.76 5.17 1.43 [1.31–1.54] 1.73 [1.66–1.80] p ≤ 0.001 -0.0020 0.698 Values represent the correlation coefficient (r, 95% CI), standard error of the estimate (SEE), smallest worthwhile change (SWC), mean absolute error (MAE), mean absolute percentage error (MAPE), coefficient of variation (CV, 95% CI), and fixed and proportional bias analyses Table 2 . Within-session reliability of Skyhook mat jump height measurements Variable TE CV 95% CI ICC (3,1) 95% CI ICC (3,k) 95% CI CMJ 1.8 1.45 [1.37–1.55] 0.973 [0.961–0.982] 0.970 [0.958–0.981] AJ 1.9 1.43 [1.35–1.52] 0.997 [0.996–0.998] 0.997 [0.996–0.998] Values are expressed as within-session reliability outcomes of the Skyhook mat. TE = typical error; CV = coefficient of variation; ICC = intraclass correlation coefficient; CMJ = countermovement jump; AJ = Abalakov jump. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 29 Mar, 2026 Reviewers invited by journal 29 Mar, 2026 Editor invited by journal 26 Dec, 2025 Editor assigned by journal 25 Dec, 2025 Submission checks completed at journal 25 Dec, 2025 First submitted to journal 25 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8447533","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":576246889,"identity":"51572b80-553d-4caf-95bb-4677ff9aab11","order_by":0,"name":"Deniz Şentürk","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9klEQVRIiWNgGAWjYPCCBMYGBiBKqACymZkbCCkHKoVpeXAGpIWRaC1A1sM2mAAeIN/ee/wx75402X7p5uYPifNqo/nbgVp+VGzDqcXgzLnEZp5nOcYz5xxsMEjcdjx3xmHGBsaeM7dxa5HIMWzmOVCRuOFGYkNC4rZjuQ1ALcyMbbi1yM9/A9GyH6jlQOKcY7nzCWlhuMED0pKTuEEisbEhsaEmdwMhLQZncgxnzjmQZjzjRmIzQ8KxA7kbgVoO4vOLfPsZgw9vDiTL9s9If/zxR01d7rzzhw8++FGBx2Fo4DCYPEC0eiCoI0XxKBgFo2AUjBAAALpfZgl/QQL6AAAAAElFTkSuQmCC","orcid":"","institution":"Gelişim Üniversitesi","correspondingAuthor":true,"prefix":"","firstName":"Deniz","middleName":"","lastName":"Şentürk","suffix":""},{"id":576246890,"identity":"e3edbc08-bb7e-49c0-ad1a-85aed1cc5336","order_by":1,"name":"Onur Topuz","email":"","orcid":"","institution":"Gelişim Üniversitesi","correspondingAuthor":false,"prefix":"","firstName":"Onur","middleName":"","lastName":"Topuz","suffix":""},{"id":576246894,"identity":"bd9a5b9a-fde7-4192-a6a1-3015ae4dfa9b","order_by":2,"name":"Faruk Aktas","email":"","orcid":"","institution":"Ege University","correspondingAuthor":false,"prefix":"","firstName":"Faruk","middleName":"","lastName":"Aktas","suffix":""},{"id":576246896,"identity":"e729877a-7bb3-4721-9b8b-816a1f4de837","order_by":3,"name":"Abdulkadir Kutluca","email":"","orcid":"","institution":"Istanbul University Cerrahpaşa","correspondingAuthor":false,"prefix":"","firstName":"Abdulkadir","middleName":"","lastName":"Kutluca","suffix":""},{"id":576246900,"identity":"d65b45b4-f02f-40f9-9e08-49d0c6a01927","order_by":4,"name":"Osman Çoşkun","email":"","orcid":"","institution":"Istanbul University","correspondingAuthor":false,"prefix":"","firstName":"Osman","middleName":"","lastName":"Çoşkun","suffix":""}],"badges":[],"createdAt":"2025-12-25 08:23:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8447533/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8447533/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101201324,"identity":"594ff761-29ee-4259-93f9-37ff6ab1c218","added_by":"auto","created_at":"2026-01-27 09:15:11","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":3462493,"visible":true,"origin":"","legend":"\u003cp\u003eAlignment and positioning of the Skyhook jump mat on the VALD ForceDecks force plate\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-8447533/v1/af1f418b91092992ec1b5eb5.png"},{"id":101201322,"identity":"a529e257-05b8-4f2a-846b-cbde00607281","added_by":"auto","created_at":"2026-01-27 09:15:10","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":548309,"visible":true,"origin":"","legend":"\u003cp\u003eCMJ height across repeated trials measured by the force plate and the Skyhook mat\u003c/p\u003e\n\u003cp\u003eLinear mixed-effects model for CMJ height, comparing the Skyhook jump mat with the force plate. Solid line represents the regression line; dashed line represents the line of identity.\u003c/p\u003e","description":"","filename":"Figure2CMJ.png","url":"https://assets-eu.researchsquare.com/files/rs-8447533/v1/c6ca2c70f9087ef9db08228b.png"},{"id":101201325,"identity":"b21b08a4-7f46-469f-9f29-17d7a52ed354","added_by":"auto","created_at":"2026-01-27 09:15:11","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":535810,"visible":true,"origin":"","legend":"\u003cp\u003eAJ height across repeated trials measured by the force plate and the Skyhook mat\u003c/p\u003e\n\u003cp\u003eLinear mixed-effects model for AJ height, comparing the Skyhook jump mat with the force plate. Solid line represents the regression line; dashed line represents the line of identity.\u003c/p\u003e","description":"","filename":"Figure3AJ.png","url":"https://assets-eu.researchsquare.com/files/rs-8447533/v1/db9824842d32795b4cf2c7d5.png"},{"id":101207189,"identity":"8c7d6f56-4fd2-4ae6-a162-1b9e9fa2b0c4","added_by":"auto","created_at":"2026-01-27 09:58:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5777453,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8447533/v1/113d5db8-ead9-44db-adfe-b038f9cc955d.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Concurrent Validity and Reliability of the Skyhook Jump Mat for Measuring Countermovement and Abalakov Jump","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe vertical jump (VJ) test is widely used to evaluate an athlete\u0026rsquo;s power [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] and fatigue status. It is also known that various performance variables in vertical jump (VJ) tests are highly associated with abilities such as sprint speed [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] and change of direction ability [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The capacity to generate explosive force during a jump is strongly associated with sport-specific actions [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], such as sprinting [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], jumping [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], and cutting [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. These movement patterns are essential for athletic performance in basketball [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], soccer [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], and volleyball [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], where optimal neuromuscular coordination and force production are critical. Accordingly, numerous standardized VJ protocols have been established to evaluate these performance capacities in both research and applied settings.\u003c/p\u003e \u003cp\u003eSeveral VJ protocols, including the Abalakov Jump (AJ), Countermovement Jump (CMJ), Drop Jump, and 10/5 Rebound Jump, are commonly used by coaches to obtain jump height (JH), reactive strength index (RSI), and ground contact time (GCT) values [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Due to its simplicity, reproducibility, and strong relationship with sport performance, the CMJ has been widely adopted by strength and conditioning coaches and sports scientists, and within this test, JH emerges as the most frequently reported parameter as it provides a valid and direct indicator of lower-limb explosive power [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. To measure JH and related variables, numerous devices have been developed, including 3D motion capture systems [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], force platforms [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], linear position transducers [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], contact mats [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], accelerometers [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], and mobile applications [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. While these devices employ different methodologies, only motion capture systems and force platforms are considered the \u0026ldquo;gold standard,\u0026rdquo; as they directly assess center of mass displacement and take-off velocity (TOV) [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Despite their accuracy, force platforms and 3D motion capture systems are not widely adopted in applied settings due to their high cost and lengthy setup [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In addition, these devices require the payment of a high annual software license fee, which further increases the overall cost and represents a major challenge for their routine use [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. These limitations have prompted the search for more practical and portable solutions to assess jump performance in applied settings.\u003c/p\u003e \u003cp\u003eJump mats stand out due to features such as portability, affordability, and user-friendly software. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. They allow rapid acquisition of JH which has increased their appeal among sports scientists and coaches [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Notably, the Skyhook (RDM Innovation, Largo, Florida) includes integrated software with data storage, enabling more effective monitoring of training sessions. In addition, the Skyhook mat\u0026rsquo;s free software increases its accessibility for coaches and practitioners. However, all jump mats estimate JH using the time-in-air (TIA) method, and outcomes may vary depending on calculation equations and hardware properties, such as micro-switch sensitivity and efficiency [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In summary, jump mats that rely on the TIA method represent a practical alternative to more complex laboratory-based systems [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Nevertheless, independent studies are required to establish the validity and reliability of each device before they can be confidently implemented in practice [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Therefore, the primary aim of the present study was to evaluate the concurrent validity of the Skyhook mat for assessing CMJ and AJ jump height, using a force plate as the criterion reference. A secondary aim was to evaluate the within-session reliability of the Skyhook mat, thereby determining its consistency as a field-based measurement tool.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003e\u003cstrong\u003eExperimental approach to the problem\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA concurrent measurement design was applied to investigate the accuracy of the Skyhook jump mat in assessing jump height compared with a force platform as the criterion reference. In addition to examining concurrent validity, the study also aimed to evaluate the within-session reliability of the Skyhook by analyzing potential differences across repeated trials. The study protocol included one familiarization session followed by two experimental sessions. During each experimental session, subjects performed five CMJ and five AJ trials in a randomized order. \u003cstrong\u003eIn all testing sessions, CMJ and AJ were performed simultaneously on the force platform and the Skyhook mat to allow direct comparison between devices.\u003c/strong\u003e Furthermore, by recruiting a relatively large sample size, the study sought to determine whether proportional bias exists at different jump heights, thereby providing deeper insights into the performance of the Skyhook across a wide range of outputs. All testing procedures were carried out in the university research laboratory under standardized environmental conditions (temperature 22\u0026ndash;24\u0026deg;C, relative humidity ~60%) and supervised by the same researcher (DS).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eEthics Approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study adhered to the Declaration of Helsinki and was approved by the Institutional Ethics Committee of Istanbul Gelisim University (Approval No: 2025/0692). Prior to data collection, all subjects were provided with a detailed verbal explanation of the procedures and signed an informed consent form, confirming their voluntary participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSubjects\u003cem\u003e\u003cbr\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eFifty-four recreationally active individuals (17 females and 37 males), with an average age of 20.9 years (standard deviation [SD]: 1.7 years; range: 20\u0026ndash;36 years), voluntarily enrolled in this study. The subjects exhibited a mean body mass of 73.3 kg (SD: 16.4 kg) and a body height of 175.2 cm (SD: 7.5 cm). All subjects had previous plyometric training experience and demonstrated proper technique during the familiarization session. \u003cstrong\u003eNote that all subjects regularly performed VJ exercise, as part of their RT programs.\u003c/strong\u003e None of the subjects had any physical limitations or neuromuscular injuries that could interfere with safe participation in the study. Subjects were instructed to refrain from strenuous lower-body exercise throughout the experimental period and to arrive at each testing session in a rested state.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eProcedures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eFamiliarization session (session 1)\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe familiarization session commenced with a detailed explanation of the study protocol and the procedures to be followed. Subjects were thoroughly briefed on the CMJ and AJ protocols, including their proper execution. Individuals who agreed to participate provided written informed consent before being formally enrolled in the study. Anthropometric assessments, including height and body mass, were subsequently recorded. Following this, subjects completed a standardized general warm-up consisting of light jogging and dynamic joint mobilization. This was followed by bodyweight CMJs and AJ performed at approximately 70%, 80%, 90%, and 100% of each subject\u0026rsquo;s perceived maximal effort as a jump-specific warm-up. After the warm-up routines, subjects executed five CMJ and five AJ trials on both the force platform and the Skyhook mat to become accustomed to the simultaneous measurement procedure. Subjects were instructed to perform all jumps with maximal effort and proper technique. All subjects were already familiar with VJ based movements as part of their regular training routines, and this session ensured they could perform the tasks with correct execution and consistency. Subjects who failed to demonstrate technical proficiency were excluded from further study participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExperimental protocol (sessions 2-3)\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFollowing the warm-up, which was identical to the routines performed during the familiarization session, subjects were positioned on the Skyhook mat placed directly on top of the force platform (ForceDecks, FDLite V.2, VALD, Brisbane, Australia). Before initiating each set of jumps, they were instructed to stand motionless until their body weight was accurately recorded by the software [25]. The CMJ protocol required subjects to start from an upright standing position, with a straight torso, fully extended knees, and feet shoulder-width apart. After the countdown signal \u0026ldquo;3, 2, 1, go,\u0026rdquo; subjects performed a rapid countermovement to a self-selected depth, immediately followed by an explosive upward motion to maximize jump height [26]. For the AJ trials, the protocol was identical to the CMJ, except that subjects were allowed free arm movement to enhance jump performance [27]. In all trials, subjects were verbally encouraged to move as vertically as possible and achieve maximal jump height. Subjects began the experimental sessions in a randomized order, starting either with CMJ or AJ. A one-minute rest interval was provided between five consecutive jumps, and a five-minute passive recovery period was given between the two protocols.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003eMeasurement equipment and data analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe temporal occurrence of all jumps was recorded concurrently by means of a jump mat (Skyhook, RDM Innovation, Largo, Florida, USA) positioned directly on top of a portable force platform (FDLite ForceDecks dual force platforms; VALD, Brisbane, Australia). The corners of the force plate\u0026rsquo;s protective foam cover were marked with white tape in a cross pattern to ensure that the Skyhook device could be precisely centered. The Skyhook was then positioned directly over these markings, aligning perfectly with the middle of the force plate. In addition, a rectangular frame was drawn with white tape on top of the Skyhook, corresponding to the two individual plates of the force platform, to ensure that subjects performed their jumps with both feet placed correctly on the force plates (see Figure 1). The Skyhook device was connected to its proprietary mobile software (version 3.4.4), which is compatible with iOS. This software enables the real-time acquisition of jump height values. Jump height from both the Skyhook mat and the force plate was calculated using the flight-time method, while the force plate simultaneously measured vertical ground reaction forces at a sampling frequency of 1000 Hz [28]. Both systems were firmly fixed to the ground and synchronized to ensure concurrent data collection during all CMJ and AJ. Successful jump attempts captured by the Skyhook were automatically transferred in real time to Microsoft Excel, thereby enabling immediate data storage, organization, and analysis, while also preventing overlap between concurrently recorded jumps.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eStatistical analyses\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDescriptive statistics are presented as mean and standard deviation (SD) for all demographic variables. Pearson product\u0026ndash;moment correlation coefficients (r) with 95% confidence intervals (95% CI) were calculated to assess the linear association between the two devices. The coefficient of variation (CV%) and corresponding 95% CI were computed \u0026nbsp;to evaluate the relative variability of Skyhook measurements compared with the criterion force plate values (CV% = [Typical Error / Mean] \u0026times; 100) [29]. The standard error of the estimate (SEE) was also calculated to provide an index of the prediction error of the regression model between devices. In addition, the smallest worthwhile change (SWC), calculated as 0.2 \u0026times; SD, was compared with the standard error of estimate (SEE) to determine the device\u0026rsquo;s sensitivity in detecting meaningful changes in jump performance. The mean absolute error (MAE) and mean absolute percentage error (MAPE) were computed to provide complementary measures of absolute and relative differences between devices. To examine the agreement between the Skyhook and the Force-plate devices, we applied a Linear Mixed-Effects Model (LMM). In this model, device (Skyhook vs. Force plate) was included as a fixed effect, while participant ID was modeled as a random intercept to account for repeated measures within individuals. Model estimates are reported as regression coefficients with 95% CI, and p-values. Within-session reliability was assessed using the CV%, calculated as the standard deviation divided by the mean of repeated trials for each participant, with group mean CV% reported across all subjects [29]. In addition, the typical error of measurement (TE) and intraclass correlation coefficients [ICC(3,1) and ICC(3,k)] were computed to provide complementary indices of absolute and relative reliability [30]. Figures were prepared in JASP (version 0.19.3; Amsterdam, The Netherlands). All statistical analyses were conducted in Python (version 3.11; Python Software Foundation, Wilmington, DE, USA). Statistical significance was set at p \u0026le; 0.05.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eConcurrent validity analyses demonstrated that both CMJ and AJ values obtained from the Skyhook mat showed an almost perfect association with the criterion force plate (r = 0.997, 95% CI: 0.997\u0026ndash;0.998 for both jump types). Measurement errors were low, with SEE values of 1.87 cm for CMJ and 1.90 cm for AJ, and corresponding MAE values of 1.74 cm and 1.76 cm, respectively. MAPE remained around 5% for both jump types (CMJ = 5.72%; AJ = 5.17%). The coefficient of variation (CV) values were well below the 10% threshold, confirming high measurement consistency. Specifically, CV was 1.45% (95% CI: 1.34\u0026ndash;1.57) for CMJ and 1.43% (95% CI: 1.31\u0026ndash;1.54) for AJ. \u0026nbsp;Importantly, SEE values were smaller than the corresponding SWC (CMJ = 1.92 cm; AJ = 2.29 cm), indicating that the Skyhook mat is sufficiently sensitive to detect small but meaningful changes in jump performance (Table 1).\u003c/p\u003e\n\u003cp\u003eLMM analyses identified a fixed bias, with the Skyhook mat systematically overestimating jump height relative to the force plate by approximately 1.73 cm for CMJ (95% CI: 1.67\u0026ndash;1.79 cm, p \u0026le; 0.001) and 1.74 cm for AJ (95% CI: 1.67\u0026ndash;1.80 cm, p \u0026le; 0.001). However, no proportional bias was detected, as indicated by non-significant regression slopes (CMJ: slope = 0.0016, p = 0.793; AJ: slope = \u0026ndash;0.0020, p = 0.698) (Figures 2 and 3). Overall, these results indicate that although the Skyhook mat consistently overestimated jump height by ~1.7 cm compared with the force plate, the device exhibited excellent agreement (r = 0.997) and high validity (CV \u0026lt; 2%) across both CMJ and AJ measurements (Table 1).\u003c/p\u003e\n\u003cp\u003e[Table 1]\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e[Figure 1]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e[Figure 2]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eWithin-session reliability analyses further confirmed the consistency of Skyhook measurements. CV across repeated trials was 1.45% for CMJ (95% CI: 1.37\u0026ndash;1.55) and 1.43% for AJ (95% CI: 1.35\u0026ndash;1.52), indicating very low relative variability. TE values were small (1.8 cm for CMJ; 1.9 cm for AJ), corresponding to approximately 2% of the mean jump height. ICC based on a two-way mixed-effects model with absolute agreement also supported excellent reliability, with ICC (3,1) = 0.973 (95% CI: 0.962\u0026ndash;0.983) for single measures and ICC (3,k) = 0.970 (95% CI: 0.958\u0026ndash;0.981) when repeated trials were averaged. (Table 2). Collectively, these results demonstrate that the Skyhook mat provides highly reliable measurements of jump performance within a single testing session.\u003c/p\u003e\n\u003cp\u003e[Table 2]\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study was designed to examine the concurrent validity of the Skyhook jump mat in measuring CMJ and AJ height relative to a force plate, as well as to assess within-session reliability. These results indicate that although the device consistently overestimates jump height by approximately 1.7 cm as a fixed bias, it remains proportionally consistent across a wide range of jump heights (13.8\u0026ndash;68.9 cm). In addition, an almost perfect relationship was observed between the two devices (r = 0.997), accompanied by low measurement error (CMJ: 1.87, AJ: 1.90), low CV (CMJ: 1.45%, AJ: 1.43%), acceptable MAE (CMJ: 1.74, AJ: 1.76), and MAPE (CMJ: 5.72%, AJ: 5.17%). Furthermore, within-session reliability analyses revealed excellent consistency (CMJ: TE = 1.8, CV = 1.45%, ICC = 0.973; AJ: TE = 1.9, CV = 1.43%, ICC = 0.997). Our findings suggest that, despite the presence of a systematic measurement error compared with the force plate, no proportional bias was evident, and the Skyhook mat exhibited nearly perfect reliability across repeated trials.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The SWC analysis further indicated that the measurement error of the Skyhook mat (SEE = 1.87 cm for CMJ; 1.90 cm for AJ) was smaller than the smallest worthwhile change (SWC = 1.92 cm for CMJ; 2.29 cm for AJ). These findings suggest that the device is sufficiently sensitive to detect small but meaningful changes in jump performance, reinforcing its practical applicability in athlete monitoring [31]. More importantly, beyond the 2 cm benchmark, the key strength of the Skyhook mat is that its measurement error is approximately constant across the observed range of jump heights and highly consistent across repeated trials. The absence of proportional bias (CMJ slope = 0.0016, p = 0.793; AJ slope = \u0026minus;0.0020, p = 0.698) indicates that the device provides stable estimates across different jump heights, supporting its applicability in athlete groups with varying performance levels. At the same time, the very low within-session variability demonstrates near perfect within-repetition repeatability. Consequently, when the Skyhook is used consistently, observed changes are unlikely to be driven by random fluctuation across trials, which reinforces the utility of the Skyhook for session-to-session monitoring.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA number of studies have previously examined the concurrent validity of devices using the flight-time method [23] against gold-standard laboratory systems, such as force plates [21] and motion capture [32]. Research conducted in comparison with force plates has consistently demonstrated that jump mats tend to report higher values than criterion measures for both CMJ and squat jumps, with overestimations of approximately 1-3 cm [19, 33, 34]. These discrepancies can be attributed to the divergent methodologies employed by the two systems. While both systems estimate jump height using the flight-time method, force plates calculate flight time based on vertical ground reaction forces recorded with high-frequency sensors (ranging from 1000 Hz to 10 000 Hz) [35]. In contrast, jump mats rely on pressure-sensitive sensors that only detect foot contact events [37]. It appears that, depending on the sampling frequency, these differences in event detection can cause a small increase in flight time, leading to a systematic overestimation of jump height. [36]. As indicated by the findings of studies employing two-dimensional and three-dimensional motion capture systems, analogous inconsistencies have also been observed [37, 38]. The discrepancies observed have been ascribed primarily to variations in ankle positioning during take-off and landing [37]. Furthermore, extant research has indicated that variations in jump height estimation may also be influenced by factors such as footwear and surface characteristics [39], device sampling frequency, and embedded software algorithms [38]. This systematic bias may be primarily explained by differences in sensor technology, as force plates detect flight time through high-frequency ground reaction force signals, whereas jump mats rely on pressure-sensitive switches that are more prone to slight delays in event detection [16]. Reflecting these methodological differences and contextual influences, the present study demonstrated that the Skyhook mat consistently overestimated jump height by around 1.7 cm for both CMJ and AJ jumps.\u003c/p\u003e\n\u003cp\u003eOur findings demonstrate that the Skyhook jump mat slightly and systematically overestimates jump height compared with a force plate, while not introducing any proportional bias. This systematic difference is likely attributable to several factors discussed above, including sensor characteristics [16], sampling frequency [35], and methodological variations [37]. Future research should aim to further investigate these potential sources of error. It is noteworthy that the TE was smaller than the SWC, indicating that the device is sufficiently sensitive to detect practically meaningful changes in jump performance [40]. Furthermore, the device demonstrated nearly perfect reliability across repeated trials, reinforcing its consistency. Taken together, these results support the use of the Skyhook mat as a practical alternative to laboratory-based systems in sports science research and athlete monitoring.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, the Skyhook jump mat provides accurate assessments of CMJ and AJ jump heights relative to a force plate, although it consistently shows a small systematic overestimation. The absence of proportional bias ensures that the device can be used reliably across athletes with different performance levels. In addition, its near-perfect trial-to-trial reliability and ability to detect performance changes beyond the standard error of measurement make it a practical option for monitoring athletes\u0026rsquo; performance. \u003cstrong\u003eMoreover, the fact that the device does not require a software license fee represents a major advantage, further enhancing its applicability and sustainability in field settings.\u003c/strong\u003e Therefore, the Skyhook jump mat can be considered a strong alternative to laboratory-based systems in sports science research and athlete monitoring.\u0026nbsp;\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank all participants for their time, effort, and commitment throughout the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eD.S. designed the study, collected the data, conducted the statistical analyses, and drafted the manuscript. F.A., O.C., O.T., and A.K. contributed to data interpretation, methodological decisions, and manuscript revisions. All authors reviewed and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eCode availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCode used for data processing and statistical analyses is available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKons, R. L., Ache-Dias, J., Detanico, D. \u0026amp; Barth, J. Dal Pupo, J. Is vertical jump height an indicator of athletes' power output in different sport modalities? \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e32\u003c/b\u003e, 708\u0026ndash;715 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWashif, J. A. \u0026amp; Kok, L. Y. Relationships between vertical jump metrics and sprint performance, and qualities that distinguish between faster and slower sprinters. \u003cem\u003eJ. Sci. Sport Exerc.\u003c/em\u003e \u003cb\u003e4\u003c/b\u003e, 135\u0026ndash;144 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVescovi, J. D. \u0026amp; McGuigan, M. R. Relationships between sprinting, agility, and jump ability in female athletes. \u003cem\u003eJ. Sports Sci.\u003c/em\u003e \u003cb\u003e26\u003c/b\u003e, 97\u0026ndash;107 (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWisl\u0026oslash;ff, U., Castagna, C., Helgerud, J., Jones, R. \u0026amp; Hoff, J. Strong correlation of maximal squat strength with sprint performance and vertical jump height in elite soccer players. \u003cem\u003eBr. J. Sports Med.\u003c/em\u003e \u003cb\u003e38\u003c/b\u003e, 285\u0026ndash;288 (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSargent, L. W. Some observations on the Sargent test of neuromuscular efficiency. \u003cem\u003eAm. Phys. Educ. Rev.\u003c/em\u003e \u003cb\u003e29\u003c/b\u003e, 47\u0026ndash;56 (1924).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarnes, J. L. et al. Relationship of jumping and agility performance in female volleyball athletes. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e21\u003c/b\u003e, 1192\u0026ndash;1196 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcFarland, I. T., Dawes, J. J., Elder, C. L. \u0026amp; Lockie, R. G. Relationship of two vertical jumping tests to sprint and change of direction speed among male and female collegiate soccer players. \u003cem\u003eSports (Basel)\u003c/em\u003e. \u003cb\u003e4\u003c/b\u003e, 11 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShalfawi, S. A., Sabbah, A., Kailani, G., T\u0026oslash;nnessen, E. \u0026amp; Enoksen, E. The relationship between running speed and measures of vertical jump in professional basketball players: a field-test approach. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e25\u003c/b\u003e, 3088\u0026ndash;3092 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarkovic, G., Dizdar, D., Jukic, I. \u0026amp; Cardinale, M. Reliability and factorial validity of squat and countermovement jump tests. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e18\u003c/b\u003e, 551\u0026ndash;555 (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYoung, W. A simple method for evaluating the strength qualities of the leg extensor muscles and jumping abilities. \u003cem\u003eStrength. Cond Coach\u003c/em\u003e. \u003cb\u003e2\u003c/b\u003e, 5\u0026ndash;8 (1995).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu, J. et al. A narrative review of rebound jumping and fast stretch-shortening cycle mechanics. \u003cem\u003eStrength. Cond J.\u003c/em\u003e \u003cb\u003e47\u003c/b\u003e, 302\u0026ndash;316. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/SSC.0000000000000878\u003c/span\u003e\u003cspan address=\"10.1519/SSC.0000000000000878\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2025).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlba-Jim\u0026eacute;nez, C., Moreno-Doutres, D. \u0026amp; Pe\u0026ntilde;a, J. Trends assessing neuromuscular fatigue in team sports: a narrative review. \u003cem\u003eSports (Basel)\u003c/em\u003e. \u003cb\u003e10\u003c/b\u003e, 33. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/sports10030033\u003c/span\u003e\u003cspan address=\"10.3390/sports10030033\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArag\u0026oacute;n, L. F. Evaluation of four vertical jump tests: methodology, reliability, validity, and accuracy. \u003cem\u003eMeas. Phys. Educ. Exerc. Sci.\u003c/em\u003e \u003cb\u003e4\u003c/b\u003e, 215\u0026ndash;228 (2000).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWalsh, M. S., Ford, K. R., Bangen, K. J., Myer, G. D. \u0026amp; Hewett, T. E. The validation of a portable force plate for measuring force-time data during jumping and landing tasks. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e20\u003c/b\u003e, 730\u0026ndash;734. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/R-18225.1\u003c/span\u003e\u003cspan address=\"10.1519/R-18225.1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRuiz-Alias, S. A. et al. Validity and reliability of velocity and power measures provided by the Vitruve linear position transducer. \u003cem\u003ePLoS One\u003c/em\u003e. \u003cb\u003e19\u003c/b\u003e, e0312348. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0312348\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0312348\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarc\u0026iacute;a-L\u0026oacute;pez, J., Morante, J. C., Ogueta-Alday, A. \u0026amp; Rodr\u0026iacute;guez-Marroyo, J. A. The type of mat (contact vs. photocell) affects vertical jump height estimated from flight time. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e27\u003c/b\u003e, 1162\u0026ndash;1167. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/JSC.0b013e31826520d7\u003c/span\u003e\u003cspan address=\"10.1519/JSC.0b013e31826520d7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStanton, R., Doering, T., Macgregor, C., Borges, N. \u0026amp; Del Vecchio, L. Validity of a contact mat and accelerometric system to assess countermovement jump from flight time. \u003cem\u003eMeas. Phys. Educ. Exerc. Sci.\u003c/em\u003e \u003cb\u003e23\u003c/b\u003e, 39\u0026ndash;46. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/1091367X.2018.1493593\u003c/span\u003e\u003cspan address=\"10.1080/1091367X.2018.1493593\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŞent\u0026uuml;rk, D., Y\u0026uuml;ksel, O. \u0026amp; Akyildiz, Z. The concurrent validity and reliability of the My Jump Lab smartphone app for the real-time measurement of vertical jump performance. Proc. Inst. Mech. Eng. P J. Sports Eng. Technol. 17543371241246439 (2024). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1177/17543371241246439\u003c/span\u003e\u003cspan address=\"10.1177/17543371241246439\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBuckthorpe, M., Morris, J. \u0026amp; Folland, J. P. Validity of vertical jump measurement devices. \u003cem\u003eJ. Sports Sci.\u003c/em\u003e \u003cb\u003e30\u003c/b\u003e, 63\u0026ndash;69. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/02640414.2011.624539\u003c/span\u003e\u003cspan address=\"10.1080/02640414.2011.624539\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerrigan, J. J. et al. Applying force plate technology to inform human performance programming in tactical populations. \u003cem\u003eAppl. Sci.\u003c/em\u003e \u003cb\u003e11\u003c/b\u003e, 6538. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/app11146538\u003c/span\u003e\u003cspan address=\"10.3390/app11146538\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePueo, B., Penichet-Tom\u0026aacute;s, A. \u0026amp; Jimenez-Olmedo, J. M. Reliability and validity of the Chronojump open-source jump mat system. \u003cem\u003eBiol. Sport\u003c/em\u003e. \u003cb\u003e37\u003c/b\u003e, 255\u0026ndash;259. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5114/biolsport.2020.95636\u003c/span\u003e\u003cspan address=\"10.5114/biolsport.2020.95636\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eConde, A., Gonz\u0026aacute;lez-Devesa, D., Su\u0026aacute;rez Iglesias, D. \u0026amp; Ay\u0026aacute;n, C. The validity and reliability of a portable device (ADR-Jumping) to estimate vertical jump performance. Proc. Inst. Mech. Eng. P J. Sports Eng. Technol. 239, 349\u0026ndash;355 (2025). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1177/17543371221127079\u003c/span\u003e\u003cspan address=\"10.1177/17543371221127079\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu, J. et al. A systematic review of the different calculation methods for measuring jump height during the countermovement and drop jump tests. \u003cem\u003eSports Med.\u003c/em\u003e \u003cb\u003e53\u003c/b\u003e, 1055\u0026ndash;1072. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s40279-023-01828-x\u003c/span\u003e\u003cspan address=\"10.1007/s40279-023-01828-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuppy, S. N. et al. The agreement between a portable contact-mat and force-plates during bilateral vertical jumps. \u003cem\u003eInt. J. Exerc. Sci.\u003c/em\u003e \u003cb\u003e15\u003c/b\u003e, 632\u0026ndash;644 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCollings, T. J., Lima, Y. L., Dutaillis, B. \u0026amp; Bourne, M. N. Concurrent validity and test-retest reliability of VALD ForceDecks' strength, balance, and movement assessment tests. \u003cem\u003eJ. Sci. Med. Sport\u003c/em\u003e. \u003cb\u003e27\u003c/b\u003e, 572\u0026ndash;580. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jsams.2024.04.014\u003c/span\u003e\u003cspan address=\"10.1016/j.jsams.2024.04.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClaudino, J. G. et al. The countermovement jump to monitor neuromuscular status: a meta-analysis. \u003cem\u003eJ. Sci. Med. Sport\u003c/em\u003e. \u003cb\u003e20\u003c/b\u003e, 397\u0026ndash;402. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jsams.2016.08.011\u003c/span\u003e\u003cspan address=\"10.1016/j.jsams.2016.08.011\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodr\u0026iacute;guez-Rosell, D., Mora-Custodio, R., Franco-M\u0026aacute;rquez, F., Y\u0026aacute;\u0026ntilde;ez-Garc\u0026iacute;a, J. M. \u0026amp; Gonz\u0026aacute;lez-Badillo, J. J. Traditional vs. sport-specific vertical jump tests: reliability, validity, and relationship with the legs strength and sprint performance in adult and teen soccer and basketball players. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e31\u003c/b\u003e, 196\u0026ndash;206. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/JSC.0000000000001476\u003c/span\u003e\u003cspan address=\"10.1519/JSC.0000000000001476\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerrigan, J. J. et al. Countermovement jump force-time curve analyses: reliability and comparability across force plate systems. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e38\u003c/b\u003e, 30\u0026ndash;37. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/JSC.0000000000004586\u003c/span\u003e\u003cspan address=\"10.1519/JSC.0000000000004586\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHopkins, W. G. Measures of reliability in sports medicine and science. \u003cem\u003eSports Med.\u003c/em\u003e \u003cb\u003e30\u003c/b\u003e, 1\u0026ndash;15. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2165/00007256-200030010-00001\u003c/span\u003e\u003cspan address=\"10.2165/00007256-200030010-00001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2000).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoo, T. K. \u0026amp; Li, M. Y. A guideline of selecting and reporting intraclass correlation coefficients for reliability research. \u003cem\u003eJ. Chiropr. Med.\u003c/em\u003e \u003cb\u003e15\u003c/b\u003e, 155\u0026ndash;163. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jcm.2016.02.012\u003c/span\u003e\u003cspan address=\"10.1016/j.jcm.2016.02.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBatterham, A. M. \u0026amp; Hopkins, W. G. Making meaningful inferences about magnitudes. \u003cem\u003eInt. J. Sports Physiol. Perform.\u003c/em\u003e \u003cb\u003e1\u003c/b\u003e, 50\u0026ndash;57 (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePueo, B., Lipinska, P., Jim\u0026eacute;nez-Olmedo, J. M., Zmijewski, P. \u0026amp; Hopkins, W. G. Accuracy of jump-mat systems for measuring jump height. \u003cem\u003eInt. J. Sports Physiol. Perform.\u003c/em\u003e \u003cb\u003e12\u003c/b\u003e, 959\u0026ndash;963. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1123/ijspp.2016-0511\u003c/span\u003e\u003cspan address=\"10.1123/ijspp.2016-0511\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKenny, I. C., Caireall\u0026aacute;in, \u0026Oacute;., Comyns, T. M. \u0026amp; A. \u0026amp; Validation of an electronic jump mat to assess stretch-shortening cycle function. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e26\u003c/b\u003e, 1601\u0026ndash;1608. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/JSC.0b013e318234ebb8\u003c/span\u003e\u003cspan address=\"10.1519/JSC.0b013e318234ebb8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEnoksen, E., T\u0026oslash;nnessen, E. \u0026amp; Shalfawi, S. Validity and reliability of the Newtest Powertimer 300-series testing system. \u003cem\u003eJ. Sports Sci.\u003c/em\u003e \u003cb\u003e27\u003c/b\u003e, 77\u0026ndash;84 (2009).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRaymond, F. et al. Using portable force plates to assess vertical jump performance: a metrological appraisal. \u003cem\u003eSports (Basel)\u003c/em\u003e. \u003cb\u003e6\u003c/b\u003e, 149. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/sports6040149\u003c/span\u003e\u003cspan address=\"10.3390/sports6040149\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWhitmer, T. D. et al. Accuracy of a vertical jump contact mat for determining jump height and flight time. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e29\u003c/b\u003e, 877\u0026ndash;881 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSorenson, B., Kernozek, T. W., Willson, J. D., Ragan, R. \u0026amp; Hove, J. Two- and three-dimensional relationships between knee and hip kinematic motion analysis: single-leg drop-jump landings. \u003cem\u003eJ. Sport Rehabil\u003c/em\u003e. \u003cb\u003e24\u003c/b\u003e, 363\u0026ndash;372. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1123/jsr.2014-0206\u003c/span\u003e\u003cspan address=\"10.1123/jsr.2014-0206\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSch\u0026uuml;mperlin, D., Sch\u0026auml;rer, C., Kalberer, L., Ferguson, S. J. \u0026amp; Lorenzetti, S. R. Pilot study: validity and reliability of textile insoles used to measure the characteristics of landing tasks during rehabilitation and artistic gymnastics. \u003cem\u003eBMC Res. Notes\u003c/em\u003e. \u003cb\u003e16\u003c/b\u003e, 59 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMalisoux, L., Gette, P., Urhausen, A., Bomfim, J. \u0026amp; Theisen, D. Influence of sports flooring and shoes on impact forces and performance during jump tasks. \u003cem\u003ePLoS One\u003c/em\u003e. \u003cb\u003e12\u003c/b\u003e, e0186297. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0186297\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0186297\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeakley, J. et al. Testing and profiling athletes: recommendations for test selection, implementation, and maximizing information. \u003cem\u003eStrength. Cond J.\u003c/em\u003e \u003cb\u003e46\u003c/b\u003e, 159\u0026ndash;179. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1519/SSC.0000000000000784\u003c/span\u003e\u003cspan address=\"10.1519/SSC.0000000000000784\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1\u003c/strong\u003e.\u0026nbsp;Concurrent validity and measurement bias of the Skyhook mat in comparison with the force plate\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003er \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 5px;\"\u003e\n \u003cp\u003eSEE (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 5px;\"\u003e\n \u003cp\u003eSWC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 6px;\"\u003e\n \u003cp\u003eMAE (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 6px;\"\u003e\n \u003cp\u003eMAPE (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003eCV\u0026nbsp;\u003cbr\u003e\u0026nbsp;95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10px;\"\u003e\n \u003cp\u003eFixed bias (cm) 95% CI\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003eFixed bias p\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003eProportional bias (slope)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003eProportional bias p\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003eCMJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e0.997\u003c/p\u003e\n \u003cp\u003e[0.997\u0026ndash;0.998]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 5px;\"\u003e\n \u003cp\u003e1.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 5px;\"\u003e\n \u003cp\u003e1.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 6px;\"\u003e\n \u003cp\u003e1.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 7px;\"\u003e\n \u003cp\u003e5.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003cp\u003e[1.34\u0026ndash;1.57]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10px;\"\u003e\n \u003cp\u003e1.73\u003c/p\u003e\n \u003cp\u003e[1.67\u0026ndash;1.79]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003ep \u0026le; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.0016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.793\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003eAJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e0.997\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;[0.997\u0026ndash;0.998]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 5px;\"\u003e\n \u003cp\u003e1.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 5px;\"\u003e\n \u003cp\u003e2.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 6px;\"\u003e\n \u003cp\u003e1.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 7px;\"\u003e\n \u003cp\u003e5.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e1.43\u003c/p\u003e\n \u003cp\u003e[1.31\u0026ndash;1.54]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10px;\"\u003e\n \u003cp\u003e1.73\u003c/p\u003e\n \u003cp\u003e[1.66\u0026ndash;1.80]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003ep \u0026le; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e-0.0020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.698\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;Values represent the correlation coefficient (r, 95% CI), standard error of the estimate (SEE), smallest worthwhile change (SWC), mean absolute error (MAE), mean absolute percentage error (MAPE), coefficient of variation (CV, 95% CI), and fixed and proportional bias analyses\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e.\u0026nbsp;Within-session reliability of Skyhook mat jump height measurements\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003eTE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22px;\"\u003e\n \u003cp\u003eCV 95%\u0026nbsp;\u003cbr\u003e\u0026nbsp;CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 29px;\"\u003e\n \u003cp\u003eICC (3,1) 95%\u0026nbsp;\u003cbr\u003e\u0026nbsp;CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003eICC (3,k) 95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003eCMJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e1.8\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22px;\"\u003e\n \u003cp\u003e1.45\u003cbr\u003e\u0026nbsp;[1.37\u0026ndash;1.55]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 29px;\"\u003e\n \u003cp\u003e0.973\u003cbr\u003e\u0026nbsp;[0.961\u0026ndash;0.982]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.970\u003cbr\u003e\u0026nbsp;[0.958\u0026ndash;0.981]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003eAJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8px;\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22px;\"\u003e\n \u003cp\u003e1.43\u003cbr\u003e\u0026nbsp;[1.35\u0026ndash;1.52]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 29px;\"\u003e\n \u003cp\u003e0.997\u003cbr\u003e\u0026nbsp;[0.996\u0026ndash;0.998]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.997\u003cbr\u003e\u0026nbsp;[0.996\u0026ndash;0.998]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 100px;\"\u003e\n \u003cp\u003eValues are expressed as within-session reliability outcomes of the Skyhook mat. TE = typical error; CV = coefficient of variation; ICC = intraclass correlation coefficient; CMJ = countermovement jump; AJ = Abalakov jump.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"vertical jump, countermovement jump, abalakov jump, validity, reliability, force plate","lastPublishedDoi":"10.21203/rs.3.rs-8447533/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8447533/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study aimed to examine the concurrent validity of the Skyhook jump mat for measuring countermovement jump (CMJ) and Abalakov jump (AJ) height using a force plate as the criterion reference, and to assess its within-session reliability. Fifty-four trained individuals (17 females, 37 males; mean age 20.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 years) performed CMJ and AJ trials on both the Skyhook jump mat and a force plate across multiple sessions. Skyhook measurements showed an almost perfect association with the force plate (r\u0026thinsp;=\u0026thinsp;0.997) for both CMJ and AJ. Measurement errors were low (SEE\u0026thinsp;=\u0026thinsp;1.87), and SEE values were smaller than the corresponding SWC. Linear mixed-effects models indicated a fixed bias, with the Skyhook consistently overestimating jump height by approximately 1.7 cm (p\u0026thinsp;\u0026le;\u0026thinsp;0.001), while showing no proportional bias. Reliability analyses demonstrated excellent consistency across repeated trials (CMJ: CV\u0026thinsp;=\u0026thinsp;1.45%, ICC(3,1)\u0026thinsp;=\u0026thinsp;0.973; AJ: CV\u0026thinsp;=\u0026thinsp;1.43%, ICC(3,1)\u0026thinsp;=\u0026thinsp;0.997). The Skyhook jump mat slightly and systematically overestimates jump height compared with a force plate but demonstrates excellent validity, reliability, and sufficient sensitivity to detect meaningful changes in performance. These characteristics support its use as a practical and cost-effective tool for monitoring jump performance in applied sports settings.\u003c/p\u003e","manuscriptTitle":"Concurrent Validity and Reliability of the Skyhook Jump Mat for Measuring Countermovement and Abalakov Jump","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-27 09:15:01","doi":"10.21203/rs.3.rs-8447533/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"157310389459815960924220478431173469193","date":"2026-03-30T02:37:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-30T00:38:28+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-12-26T16:04:39+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-26T02:28:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-26T02:27:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-12-25T08:12:05+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"52816739-deca-43e6-8e1c-5332a2cca14b","owner":[],"postedDate":"January 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":61313011,"name":"Physical sciences/Engineering"},{"id":61313012,"name":"Health sciences/Health care"}],"tags":[],"updatedAt":"2026-03-30T00:53:15+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-27 09:15:01","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8447533","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"identity":"rs-8447533","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}