The validity and reliability of the my jump 2 app for measuring the reactive strength index and drop jump performance

Haynes, Thomas and Bishop, Chris and Antrobus, Mark and Brazier, Jon (2018) The validity and reliability of the my jump 2 app for measuring the reactive strength index and drop jump performance. Journal of Sports Medicine and Physical Fitness . ISSN 0022-4707 (Published online first)

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Abstract

BACKGROUNDː This is the first study to independently assess the concurrent validity and reliability of the My Jump 2 app for measuring drop jump performance. It is also the first to evaluate the app’s ability to measure the reactive strength index (RSI).

METHODSː Fourteen male sport science students (age: 29.5 ± 9.9 years) performed three drop jumps from 20 cm and 40 cm (totalling 84 jumps), assessed via a force platform and the My Jump 2 app. Reported metrics included reactive strength index, jump height, ground contact time, and mean power. Measurements from both devices were compared using the intraclass correlation coefficient (ICC), Pearson product moment correlation coefficient (r), Cronbach’s alpha (α), coefficient of variation (CV) and Bland-Altman plots.

RESULTSː Near perfect agreement was seen between devices at 20 cm for RSI (ICC = 0.95) and contact time (ICC = 0.99) and at 40 cm for RSI (ICC = 0.98), jump height (ICC = 0.96) and contact time (ICC = 0.92); with very strong agreement seen at 20 cm for jump height (ICC = 0.80). In comparison with the force plate the app showed good validity for RSI (20 cm: r = 0.94; 40 cm; r = 0.97), jump height (20 cm: r = 0.80; 40 cm; r = 0.96) and contact time (20 cm = 0.96; 40 cm; r = 0.98).

CONCLUSIONSː The results of the present study show that the My Jump 2 app is a valid and reliable tool for assessing drop jump performance.

Item Type: Article
Research Areas: A. > School of Science and Technology > London Sport Institute > Strength and Conditioning at the London Sport Institute
Item ID: 23570
Notes on copyright: This is an Accepted Manuscript of an article published by Edizioni Minerva Medica in Journal of Sports Medicine and Physical Fitness on 27/03/18, available online: https://doi.org/10.23736/S0022-4707.18.08195-1
Useful Links:
Depositing User: Chris Bishop
Date Deposited: 19 Feb 2018 12:28
Last Modified: 06 Sep 2018 08:18
URI: http://eprints.mdx.ac.uk/id/eprint/23570

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