Reliability of the squat jump force-velocity and load-velocity profiles

Author Identifier

Yosuke Kotan

https://orcid.org/0000-0002-1049-8354

Guy Gregory Haff

https://orcid.org/0000-0002-0676-7750

Document Type

Journal Article

Publication Title

Journal of Strength and Conditioning Research

PubMed ID

33966009

Publisher

National Strength and Conditioning Association

School

School of Medical and Health Sciences

RAS ID

36601

Comments

Kotani, Y., Lake, J., Guppy, S. N., Poon, W., Nosaka, K., Hori, N., & Haff, G. G. (2022). Reliability of the squat jump force-velocity and load-velocity profiles. The Journal of Strength and Conditioning Research, 36(11), 3000-3007.

https://doi.org/10.1519/JSC.0000000000004057

Abstract

The reliability of the squat jump force-velocity and load-velocity profiles. J Strength Cond Res XX(X): 000-000, 2021-The purpose of this study was to investigate the between-session reliability of the squat jump force-velocity (FV) and load-velocity (LV) profiles. Eighteen subjects (age = 28.1 ± 4.8 years; height = 1.7 ± 9.7; body mass = 74.7 ± 12.8) who could back squat >1.5 times body mass participated in this study. Each subject completed a familiarization session, followed by 2 experimental sessions each separated by 72 hours. Subjects performed a series of squat jumps on a force plate against external loads between 0 and 100% of their body mass in a quasi-randomized block order. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) were used to examine the between-session reliability. Peak velocity (PV) and mean velocity (MV) at each load were highly reliable (ICC >0.80, CV% <7.41, SEM <0.13 m·s-1, smallest detectable difference [SDD] <0.31 m·s-1, ES <0.21). Force-velocity profiles created with peak force and relative peak force resulted in poor to excellent reliability (ICC = 0.34-0.92, CV% = 11.9-26.3). When mean and relative mean forces were used to create FV profiles, there was poor to good reliability (ICC = 0.03-0.85, CV% = 18.1-39.4). When the LV profile was calculated with PV (ICC = 0.60-0.90, CV% = 7.9-16.9) or MV (ICC = 0.49-0.91, CV% = 11.1-23.4), there was poor to excellent reliability. There was no time effect found between sessions for both FV and LV profiles. The squat jump FV and LV profiles established with a force plate are not reliable. Therefore, these profiles are not recommended to be used to inform programming decisions.

DOI

10.1519/JSC.0000000000004057

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