Original scientific paper

https://doi.org/10.26582/k.58.1.12

Variability in back squat repetitions performed before exceeding different velocity loss thresholds

Zhaoqian Li ; School of Physical Education, Shandong University, Jinan, China
Xing Zhang ; Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
Deniz Şentürk ; School of Physical Education of Sports Department, Physical Education and Sports, Istanbul Gelişim University, Istanbul, Turkey
Zeki Akyildiz ; Department of Coaching Education, Sports Science Faculty, Afyon Kocatepe University, Afyonkarahisar, Turkey
Danica Janicijevic orcid.org/0000-0001-9925-7751 ; Faculty of Sports Science, Ningbo University, Ningbo, China; Department of Radiology, Ningbo No. 2 Hospital, Ningbo, China; Department of Sports Sciences and Physical Conditioning, Faculty of Education, Universidad Católica de la Santísima Concepción, Concepción, Chile
Amador García-Ramos orcid.org/0000-0003-0608-8755 ; Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain; Department of Sports Sciences and Physical Conditioning, Faculty of Education, Universidad Católica de la Santísima Concepción, Concepción, Chile *

* Corresponding author.

Abstract

This study aimed to evaluate the intra-individual between-day variability in the number of repetitions performed before exceeding 10%, 20%, and 30% velocity loss thresholds (VLTs) during the back squat exercise. Thirty resistance-trained male wrestlers performed sets of repetitions to failure at 70% and 80% of their 1-repetition maximum (1RM) on two separate days. Velocity loss was calculated using as the reference either the first repetition of the set or the fastest repetition. The set termination criterion specified stopping the set after one or two consecutive repetitions exceeded the prescribed VLT. Variability in repetitions was expressed as the coefficient of variation (CV), calculated as the absolute difference between sessions divided by the average repetitions across sessions. All factors, including load (70%1RM vs. 80%1RM), reference repetition (first repetition vs. fastest repetition), and set termination criterion (one vs. two repetitions exceeding the VLT), significantly affected the number of repetitions performed for the 10%, 20%, and a 30% VLT conditions (p<.01). Regardless of these factors, intra -individual variability in the number of repetitions performed between sessions was consistently high (CV > 10%). These findings highlight two key challenges when using VLTs in training prescription. First, specifying a VLT alone is insufficient, as the actual number of repetitions performed—which ultimately dictates adaptations—is influenced by multiple methodological factors. Second, even when methodological factors are standardized, the inherent variability in the number of repetitions performed across sessions remains high, which could impact acute fatigue responses and longterm training adaptations.

Keywords

fatigue monitoring; linear position transducer; muscle strength; resistance training; training volume control; velocity-based training

Hrčak ID:

348329

URI

https://hrcak.srce.hr/348329

Publication date:

30.6.2026.

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