Relationship Between Velocity Loss and Repetitions in Reserve in the Bench Press and Back Squat Exercises

Abstract

Rodríguez-Rosell, D, Yáñez-García, JM, Sánchez-Medina, L, Mora-Custodio, R, and González-Badillo, JJ. Relationship between velocity loss and repetitions in reserve in the bench press and back squat exercises. J Strength Cond Res 34(9): 2537–2547, 2020—This study aimed to compare the pattern of repetition velocity decline during a single set to failure performed against 4 relative loads in the bench press (BP) and full back squat (SQ) exercises. After an initial test to determine 1 repetition maximum (1RM) strength and load-velocity relationships, 20 men performed one set of repetitions to failure (MNR test) against loads of 50, 60, 70, and 80% 1RM in BP and SQ, on 8 random order sessions performed every 6–7 days. Velocity against the load that elicited a ∼1.00 m·s−1 (V1 m·s−1 load) was measured before and immediately after each MNR test, and it was considered a measure of acute muscle fatigue. The number of repetitions completed against each relative load showed high interindividual variability in both BP (coefficient of variation [CV]: 15–22%) and SQ (CV: 26–34%). Strong relationships were found between the relative loss of velocity in the set and the percentage of performed repetitions in both exercises (R 2 = 0.97 and 0.93 for BP and SQ, respectively). Equations to predict repetitions left in reserve from velocity loss are provided. For a given magnitude of velocity loss within the set (15–65%), the percentages of performed repetitions were lower for the BP compared with the SQ for all loads analyzed. Acute fatigue after each set to failure was found dependent on the magnitude of velocity loss (r = 0.97 and 0.99 for BP and SQ, respectively) but independent of the number of repetitions completed by each participant (p > 0.05) for both exercises. The percentage of velocity loss against the V1 m·s−1 load decreased as relative load increased, being greater for BP than SQ. These findings indicate that monitoring repetition velocity can be used to provide a very good estimate of the number (or percentage) of repetitions actually performed and those left in reserve in each exercise set, and thus to more objectively quantify the level of effort incurred during resistance training.

The Bench Press Grip Width Does Not Affect the Number of Repetitions Performed at Different Velocity Loss Thresholds

“…In this regard, one of the greatest challenges facing coaches, strength, and conditioning professionals is how to accurately prescribe training volume to elicit specific adaptations. As a potential solution, previous research has proposed using different VLTs [7][8][9] and VLT-based equations to estimate with a low inter-individual variability (CV = 2.7%-12.1%) the number of repetitions left in reserve in a set during the BP exer-cise [11,37]. However, our fourth hypothesis was rejected because a high and comparable inter-individual variability in the percentage of completed repetitions with respect to the XRM was observed for both FNR and VLT.…”

Effects of velocity loss in the bench press exercise on strength gains, neuromuscular adaptations, and muscle hypertrophy

“…19 However, the velocity loss (VL) incurred within the set, calculated as the relative difference between the fastest repetition velocity and the last repetition velocity of the set, 7 has shown strong correlations (R 2 = .96) with the percentage of completed repetitions with respect to the MNR. 5,20 Accordingly, VL can be used to accurately determine the percentage of the MNR that has been completed in the set. 5 Therefore, VBT can be considered as an alternative method to monitoring RT intensity and volume by collecting repetition velocity.…”

“…Secondly, using only the velocity attained at a given %1RM is not a proper method to predict the MNR that can be completed with such load 19 . However, the velocity loss (VL) incurred within the set, calculated as the relative difference between the fastest repetition velocity and the last repetition velocity of the set, 7 has shown strong correlations ( R 2 = .96) with the percentage of completed repetitions with respect to the MNR 5,20 . Accordingly, VL can be used to accurately determine the percentage of the MNR that has been completed in the set 5 .…”

Autoregulation in Resistance Training: Addressing the Inconsistencies

“…Following completion of the intervention, the 40% group achieved greater improvements in muscular hypertrophy, whilst the 20% group achieved greater improvements in strength and power [71]. In addition, recent research suggests that there is a stable relationship between proximity to momentary muscular failure and the velocity of a movement across different exercises [72,73]. Based on this evidence, it has been proposed that practitioners could implement absolute 'stopping velocities' that adjust the amount of volume performed in a given exercise or session [72].…”