The relationship between isometric and dynamic strength following resistance training: A systematic review, meta-analysis, and level of agreement

Abstract

Background: Maximal lower-body strength can be assessed both dynamically and isometrically; however, the relationship between the changes in these 2 forms of strength following resistance training is not well understood. Purpose: To systematically review and analyze the effects of resistance training on changes in maximal dynamic (1-repetition-maximum back squat, deadlift, and power clean) and position-matched isometric strength (isometric midthigh pull and the isometric squat). In addition, individual-level data were used to quantify the agreement and relationship between changes in dynamic and isometric strength. Methods: Databases were systematically searched to identify eligible articles, and meta-analysis procedures were performed on the extracted data. The raw results from 4 studies were acquired, enabling bias and absolute reliability measures to be calculated using Bland–Altman test of agreement. Results: Eleven studies met the inclusion criteria, which resulted in 29 isometric–dynamic change comparisons. The overall pooled effect was 0.13 in favor of dynamic testing; however, the prediction interval ranged from g = −0.49 to 0.75. There was no evidence of bias (P =.825) between isometric and dynamic tests; however, the reliability coefficient was estimated to be 16%, and the coefficient of variation (%) was 109.27. Conclusions: As a range of future effects can be expected when comparing isometric to dynamic strength changes following resistance training, and limited proportionality exists between changes in these 2 strength qualities, there is strong evidence that isometric and dynamic strength represent separate neuromuscular domains. These findings can be used to inform strength-assessment models in athlete populations.

RAS ID

64729

Document Type

Journal Article

Date of Publication

1-1-2023

Volume

19

Issue

1

School

School of Medical and Health Sciences

Copyright

free_to_read

Publisher

Human Kinetics

Comments

James, L. P., Weakley, J., Comfort, P., & Huynh, M. (2023). The relationship between isometric and dynamic strength following resistance training: A systematic review, meta-analysis, and level of agreement. International Journal of Sports Physiology and Performance, 19(1), 2-12. https://doi.org/10.1123/ijspp.2023-0066

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Link to publisher version (DOI)

10.1123/ijspp.2023-0066