The Validity of the Push Band 2.0 on the Reactive Strength Index Assessment in Drop Jump

Abstract

This study aims to verify the validity of the Push Band 2.0 (PB2.0) device on the reactive strength index (RSI) measurement, using a force plate (FP) and an optical sensor device, OptoJump (OPT), as a reference. Twenty trained athletes performed 60 drop jump trials with a height box of 30 cm. A randomized repeated measures study was conducted during a single session using the PB2.0, the OPT, and the plate force manually synchronized to obtain RSI data for each jump. Validity was analyzed by contrasting three measures: the intra-class correlation coefficient (ICC), the Bland–Altman test, and R2 coefficient of determination. Bland–Altman analysis showed that RSI and FP for PB2.0 (media = −0.047; IC 93.34%) of all data were within the confidence interval, indicating a statistically reliable result. The RSI measured by the OPT and PB2.0 also provided similar values (media = −0.047). These data are identical to other validity measures (ICC and linear correlation) but differ in the R2 values. The explained variation of PB2.0 measures attained only 29.3% of the FP (R2 = 0.293) and 29.5% (R2 = 0.295) of the OPT assessment, showing a very low determination coefficient. The results of this study point to caution in the use of PB2.0 when measuring RSI in scientific research.

Validity and reliability of the Output sport device for assessing drop jump performance

“…The study followed the same procedures outlined in previous research related to the validation and intra-session reliability of jumps assessment equipment ( Montoro-Bombú et al, 2022 ). All participants performed three DJ (for RSI assessment), with jump parameters recorded simultaneously with an FP and the IMU measurement device.…”

“…Studies have demonstrated the validity and reliability of different accelerometer devices for velocity-based training ( Balsalobre-Fernandez et al, 2016 ; Hughes et al, 2019 ; Lake et al, 2019 ), injury detection ( Li et al, 2016 ), and monitoring sleep quality ( Reimers et al, 2021 ) with high accuracy. Additionally, separate investigations have involved the validation of the functionality of these devices for the measurement of jump metrics ( Choukou et al, 2014 ; Lake et al, 2018 ; Montalvo et al, 2021 ; Montoro-Bombú et al, 2022 ). A new commercially available inertial measurement unit (IMU), namely the Output Sport measurement device, has been used for fatigue assessment ( Buckley et al, 2017 ), injury prevention ( Whelan et al, 2016 ), agility ( Johnston et al, 2019 ), velocity-based training ( O'Reilly et al, 2015 ), lower limb exercise assessments ( O'Reilly et al, 2017a ; O'Reilly et al, 2017b ; O'Reilly et al, 2018 ), and postural control and balance evaluations ( Johnston et al, 2019 ).…”

“…Furthermore, the device presents an easily transportable alternative to some of the other larger and less manageable jump measure technologies on the market. This device could be of enormous interest accounting for the intense travel schedules of elite sports ( Montoro-Bombú et al, 2022 ), providing an opportunity for monitoring athletes while away from their usual training facilities.…”

Methodological considerations for determining the volume and intensity of drop jump training. A systematic, critical and prepositive review

“…Ideally, athletes should maximize JH while minimizing ground contact time. The RSI (Young, 1995) is the proposed metric that solves these problems through the use of different devices that can be easily apply during training (Montoro-Bombú et al, 2022). So far, we have not found in the literature any study assuming that the RSI can be considered a plyometric intensity variable.…”

“…(Lees and Fahmi, 1994b), A was the first to refute all previous FH criteria and contributions (Komi and Bosco, 1978b;Bobbert et al, 1987b), indicating that the best performance for a net increase in JH, instantaneous power, and other parameters occurred at 12 cm FH. There have been considerable contributions regarding the best conditions for power production (Pw) (Bosco et al, 1983b;Matic et al, 2015b;Morin et al, 2019), ground reaction forces (GRF), rate of force development (RFD) (Jensen and Ebben, 2007;Ebben et al, 2008;Kossow and Ebben, 2018a), and the reactive strength index (RSI), as well as the differences between CMJ and DJ (Young, 1995;Young et al, 1995;Struzik et al, 2016;Montoro-Bombú et al, 2022), although not always consistent. The emergence of these variables has led to the utilization of different criteria for assuming plyometric training intensity.…”