The Acute and Chronic Effects of Implementing Velocity Loss Thresholds During Resistance Training: A Systematic Review, Meta-Analysis, and Critical Evaluation of the Literature

Abstract

Background Velocity loss (VL) experienced in a set during resistance training is often monitored to control training volume and quantify acute fatigue responses. Accordingly, various VL thresholds are used to prescribe resistance training and target different training adaptations. However, there are inconsistencies in the current body of evidence regarding the magnitude of the acute and chronic responses to the amount of VL experienced during resistance training. Objective The aim of this systematic review was to (1) evaluate the acute training volume, neuromuscular, metabolic, and perceptual responses to the amount of VL experienced during resistance training; (2) synthesize the available evidence on the chronic effects of different VL thresholds on training adaptations; and (3) provide an overview of the factors that might differentially influence the magnitude of specific acute and chronic responses to VL during resistance training. Methods This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Five databases were searched, and studies were included if they were written in English, prescribed resistance training using VL, and evaluated at least one (1) acute training volume, neuromuscular, metabolic, or perceptual response or (2) training adaptation. Risk of bias was assessed using a modified Cochrane Collaboration’s tool for assessing the risk of bias in randomized trials. Multilevel and multivariate meta-regressions were performed where possible. Results Eighteen acute and 19 longitudinal studies met the inclusion criteria, of which only one had more than one risk of bias item assessed as high risk. Based on the included acute studies, it seems that the number of repetitions per set, blood lactate concentration, and rating of perceived exertion generally increase, while countermovement jump height, running sprint times, and velocity against fixed loads generally decrease as VL increases. However, the magnitude of these effects seems to be influenced, among other factors, by the exercise and load used. Regarding training adaptations, VL experienced during resistance training did not influence muscle strength and endurance gains. Increases in VL were associated with increases in hypertrophy (b = 0.006; 95% confidence interval [CI] 0.001, 0.012), but negatively affected countermovement jump (b = − 0.040; 95% CI − 0.079, − 0.001), sprint (b = 0.001; 95% CI 0.001, 0.002), and velocity against submaximal load performance (b = − 0.018; 95% CI − 0.029, − 0.006). Conclusions A graded relationship exists between VL experienced during a set and acute training volume, neuromuscular, metabolic, and perceptual responses to resistance training. However, choice of exercise, load, and individual trainee characteristics (e.g., training history) seem to modulate these relationships. The choice of VL threshold does not seem to affect strength and muscle endurance gains whereas higher VL thresholds are superior for enhancing hypertrophy, and lower VL thresholds are superior for jumping, sprinting, and velocity against submaximal loads performance. Clinical Trial Registration The original protocol was prospectively registered (https://osf.io/q4acs/) with the Open Science Framework.

Velocity loss is a flawed method for monitoring and prescribing resistance training volume with a free-weight back squat exercise

“…During an exercise set, as the number of repetitions performed with maximal voluntary effort increases, movement velocity progressively decreases due to fatigue accumulation. Indeed, findings of several studies indicate that monitoring velocity loss (VL) experienced during a set is an objective, practical and non-invasive indicator of the acute metabolic stress, hormonal response and mechanical fatigue induced by RT (González-Badillo et al 2016;Pareja-Blanco et al 2017;Jukic et al 2022). Moreover, a very close relationship between VL and the percentage of performed repetitions out of the maximum possible in a set (% repetitions ) was observed for paused bench press and back squat exercises performed in a Smith machine with loads ranging from 50 to 85% of 1RM (González-Badillo et al 2017;Rodríguez-Rosell et al 2020).…”

The effects of velocity-based versus percentage-based resistance training on athletic performances in sport-collegiate female basketball players

“…It also compared the lifting load with individual baseline 1RM based on the corresponding movement velocity under the heavy load (back squat 0.38 ± 0.05 m/s, bench press 0.32 ± 0.05 m/s). The above comparative analyses were ignored in previous studies ( Pareja-Blanco et al, 2017 ; Dorrell et al, 2020 ; Jukic et al, 2022 ). These results provide support for the hypothesis that the lifted load weight of VBRT was higher than it is designed by percentage-based resistance training.…”

The Effect of Various Training Variables on Developing Muscle Strength in Velocity-based Training: A Systematic Review and Meta-analysis

“…Given that different variables may co-affect the specific training variable-strength relationship, we followed the method by Jukic, Castilla, Ramos et al [25] to stratify the analyses on velocity loss or intensity when the variable was not loaded as a variable of the regression. Specifically, the analyses were stratified as (1) the low velocity loss (VL < 20 %) and high velocity loss (VL ≥ 20 %) and (2) low intensity (intensity ≤ 70 %1RM) and high intensity (intensity < 70 %1RM).…”