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The reliability of novel, temporal-based dynamic strength index metrics.

James, L; Comfort, P

Authors

L James



Abstract

The purpose of this study was: i) to determine the reliability of alternate forms of the dynamic strength index (DSI) calculated over time-specific intervals that represent decisive actions in sport and ii) to assess the association between the original form of the DSI (DSI ) and its variants. Twenty-three resistance-trained males (BM = 80.4 ± 10.18 kg; age = 26.3 ± 10.2 y; 1-RM squat kg/kg/BM = 1.61 ± 0.37) performed trials of the countermovement jump (CMJ) and isometric squat. Several variations of the DSI were calculated by dividing the mean force in the CMJ by the mean force in the isometric squat calculated over the following epochs: 100 ms (DSI ), 150 ms (DSI ) and CMJ propulsive phase duration (DSI ). In the fourth method, mean force across the CMJ propulsive phase duration was divided by mean force in the isometric squat between initiation and peak force (DSI ). All alternate DSI measures achieved acceptable absolute reliability (CV < 10%), however they did not achieve at least a moderate relative reliability. DSI (  = 0.41), DSI (  = 0.03) and DSI (  = 0.14) demonstrated limited commonality with DSI . The alternate forms of DSI can cautiously be considered in strength assessment systems.

Citation

James, L., & Comfort, P. (2022). The reliability of novel, temporal-based dynamic strength index metrics. Sports Biomechanics, 1-12. https://doi.org/10.1080/14763141.2022.2032298

Journal Article Type Article
Acceptance Date Jan 17, 2022
Publication Date Feb 4, 2022
Deposit Date May 17, 2022
Journal Sports biomechanics
Print ISSN 1476-3141
Publisher Routledge
Pages 1-12
DOI https://doi.org/10.1080/14763141.2022.2032298
Keywords Strength assessment, isometric force, countermovement jump, power
Publisher URL https://www.tandfonline.com/doi/abs/10.1080/14763141.2022.2032298