Acute Effects of Intracontrast Rest After Back Squats on Vertical Jump Performance During Complex Training

Houlton, LJ, Moody, JA, Bampouras, TM ORCID: 0000-0002-8991-4655 and Esformes, JI (2024) Acute Effects of Intracontrast Rest After Back Squats on Vertical Jump Performance During Complex Training. Journal of Strength and Conditioning Research. ISSN 1064-8011

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Abstract

Post-activation performance enhancement and complex-contrast sets are prevalent in sports science research. Typical complex-contrast sets consist of heavy back squats, an intra-contrast rest period (ICRP) and vertical jumps (countermovement jumps [CMJ], or squat jumps [SJ]). Propulsive impulse (Jprop) is considered the leading indicator of jump performance. However, studies evaluating jump performance during complex-contrast sets use jump height as the primary performance measure, limiting insight into ICRP's effect on jump performance. We assessed the effect of a three-repetition maximum (3RM) back squat and six ICRPs on vertical jump Jprop and associated force-time components. Fourteen participants completed 12 experimental conditions, assigned equally to four testing sessions. Independent variables, in a 6x2 randomised, counterbalanced design, were ICRP (0, 60, 120, 180, 240, 300 s; ICRP0, ICRP60, ICRP120, ICRP180, ICRP240, ICRP300, respectively) and vertical jump (CMJ and SJ). Conditions consisted of baseline vertical jumps, followed by three back squat repetitions at 100% 3RM, an ICRP and experimental jumps. Symmetrised percentage changes between experimental and baseline jumps were assessed using repeated measures ANOVA and pairwise effect sizes. Results showed significant effects (p ≤ 0.05) on CMJ average rate of force development (RFD) between ICRP0 and ICRP120 and ICRP0 and ICRP300. Pairwise comparisons showed medium and large effect sizes for and increases in CMJ RFD (g = 0.83-2.69) while SJ RFD decreased (g = 0.81-2.57). Small effect sizes were found for Jprop, peak force and mean force. Results suggest limited change in Jprop (g = 0.01-0.58) but back squats may potentiate RFD via the stretch-shortening cycle.

Item Type:	Article
Additional Information:	This is a pre-copyedited, author-produced version of an article accepted for publication in Journal of Strength and Conditioning Research. The published version of record Houlton, Liam J.1; Moody, Jeremy A.1,2; Bampouras, Theodoros M.3; Esformes, Joseph I.1. Acute Effects of Intracontrast Rest After Back Squats on Vertical Jump Performance During Complex Training. Journal of Strength and Conditioning Research ():10.1519/JSC.0000000000004878, July 12, 2024. | DOI: 10.1519/JSC.0000000000004878 is available online https://journals.lww.com/nscajscr/abstract/9900/acute_effects_of_intracontrast_rest_after_back.472.aspx and 10.1519/JSC.0000000000004878
Uncontrolled Keywords:	1106 Human Movement and Sports Sciences; 1116 Medical Physiology; Sport Sciences
Subjects:	R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport and Exercise Sciences
Publisher:	Lippincott, Williams & Wilkins
Date of acceptance:	3 May 2024
Date of first compliant Open Access:	12 July 2025
Date Deposited:	17 May 2024 12:10
Last Modified:	12 Jul 2025 08:00
DOI or ID number:	10.1519/JSC.0000000000004878
URI:	https://researchonline.ljmu.ac.uk/id/eprint/23293

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