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Purpose: To compare the effect of 4 velocity-loss (VL) thresholds—0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)—on strength gains, neuromuscular adaptations, and muscle hypertrophy during the bench press (BP) exercise using intensities ranging from 55% to 70% of 1-repetition maximum (1RM). Methods: Fifty resistance-trained men were randomly assigned to 4 groups that followed an 8-week (16 sessions) BP training program at 55% to 70% 1RM but differed in the VL allowed in each set (VL0, VL15, VL25, and VL50). Assessments performed before (pre) and after (post) the training program included (1) cross-sectional area of pectoralis major muscle, (2) maximal isometric test, (3) progressive loading test, and (4) fatigue test in the BP exercise. Results: A significant group × time interaction was found for 1RM (P = .01), where all groups except VL0 showed significant gains in 1RM strength (P P = .03) where only the VL25 group showed significant increases (P = .02). VL50 showed decreased EMG root mean square in triceps brachii (P = .006). Only the VL50 group showed significant increases in cross-sectional area (P Conclusions: These findings indicate that a VL threshold of about 25% with intensities from 55% to 70% 1RM in BP provides an optimal training stimulus to maximize dynamic strength performance and neuromuscular adaptations, while higher VL thresholds promote higher muscle hypertrophy.

Piqueras-Sanchiz, F, Cornejo-Daza, PJ, Sanchez-Valdepenas, J, Bachero-Mena, B, Sanchez-Moreno, M, Martin-Rodriguez, S, Garcia-Garcia, O, and Pareja-Blanco, F. Acute Mechanical, Neuromuscular, and Metabolic Responses to Different Set Configurations in Resistance Training. J Strength Cond Res XX(X): 000-000, 2021-The aim of this study was to investigate the effect of set configuration on mechanical performance, neuromuscular activity, metabolic response, and muscle contractile properties. Sixteen strength-trained men performed 2 training sessions in the squat exercise consisting of (a) 3 sets of 8 repetitions with 5 minutes rest between sets (3 × 8) and (b) 6 sets of 4 repetitions with 2 minutes rest between sets (6 × 4). Training intensity (75% one repetition maximum), total volume (24 repetitions), total rest (10 minutes), and training density were equalized between protocols. A battery of tests was performed before and after each protocol: (a) tensiomyography (TMG), (b) blood lactate and ammonia concentration, (c) countermovement jump, and (d) maximal voluntary isometric contraction in the squat exercise. Force, velocity, and power output values, along with electromyography data, were recorded for every repetition throughout each protocol. The 6 × 4 protocol resulted in greater mechanical performance (i.e., force, velocity, and power) and lower neuromuscular markers of fatigue (i.e., lower root mean square and higher median frequency) during the exercise compared with 3 × 8, particularly for the last repetitions of each set. The 3 × 8 protocol induced greater lactate and ammonia concentrations, greater reductions in jump height, and greater impairments in TMG-derived velocity of deformation after exercise than 6 × 4. Therefore, implementing lower-repetition sets with shorter and more frequent interset rest intervals attenuates impairments in mechanical performance, especially in the final repetitions of each set. These effects may be mediated by lower neuromuscular alterations, reduced metabolic stress, and better maintained muscle contractile properties.

Purpose: This study aimed to compare the effects of four resistance training (RT) programs with different velocity loss (VL) thresholds: 0% (VL0), 10% (VL10), 20% (VL20) and 40% (VL40) on sprint and jump performance, muscle strength, neuromuscular, muscle hypertrophy and architectural adaptations. Methods: Sixty-four young resistance-trained men were randomly assigned into four groups (VL0, VL10, VL20, and VL40) that differed in the VL allowed in each set. Subjects followed an RT program for 8 weeks (2 sessions per week) using the full-squat (SQ) exercise, with similar relative intensity (70-85% 1RM), number of sets (3) and inter-set recovery period (4-min). Before and after the RT program the following tests were performed: 1) muscle hypertrophy and architecture of the vastus lateralis (VLA); 2) tensiomyography; 3) 20-m running sprint; 4) vertical jump; 5) maximal voluntary isometric contraction in SQ; 6) progressive loading test in SQ; and 7) fatigue test. Results: No between-group differences existed for RT-induced gains in sprint, jump and strength performance despite the differences in the total volume performed by each group. VL20 and VL40 showed significant increases (P < 0.001) in muscle hypertrophy (group × time interaction, P = 0.06). However, only VL40 exhibited a significant slowing (P < 0.001) of the delay time in the VLA muscle (group × time interaction: P = 0.05). Moreover, VL40 showed a significant decrease in the early rate of force development (P = 0.04). Conclusions: Higher VL thresholds (i.e. VL20 and VL40) maximized hypertrophic adaptations, although an excessive VL during the set (i.e. VL40) may also induce negative neuromuscular adaptations. Therefore, moderate VL thresholds should be chosen to maximize strength adaptations and to prevent negative neuromuscular adaptations.

Purpose: This study aimed to compare the adaptations provoked by various velocity loss (VL) thresholds used in resistance training on the squat force–velocity (F–V) relationship. Methods: Sixty-four resistance-trained young men were randomly assigned to one of four 8-week resistance training programs (all 70%–85% 1-repetition maximum) using different VL thresholds (VL0 = 0%, VL10 = 10%, VL20 = 20%, and VL40 = 40%) in the squat exercise. The F–V relationship was assessed under unloaded and loaded conditions in squat. Linear and hyperbolic (Hill) F–V equations were used to calculate force at zero velocity (F0), velocity at zero force (V0), maximum muscle power (Pmax), and force produced at mean velocities ranging from 0.0 to 2.0 m·s−1. Changes in parameters derived from the F–V relationship were compared among groups using linear mixed models. Results: Linear equations showed increases in F0 (120.7 N [89.4 to 152.1]) and Pmax (76.2 W [45.3 to 107.2]) and no changes in V0 (−0.02 m·s−1 [−0.11 to 0.06]) regardless of VL. Hyperbolic equations depicted increases in F0 (120.7 N [89.4 to 152.1]), V0 (1.13 m·s−1 [0.78 to 1.48]), and Pmax (198.5 W [160.5 to 236.6]) with changes in V0 being greater in VL0 and VL10 versus VL40 (both P −1 (all P −1. Conclusions: All groups improved linear and hyperbolic F0 and Pmax and hyperbolic V0 (except VL40). The dose–response relationship exhibited an inverted U-shape pattern at velocities ≤0.5 m·s−1 with VL10 and VL20 showing the greatest standardized changes.

OBJECTIVE This study aimed to compare the effects of four velocity-based training (VBT) programs in bench press (BP) between a wide range of velocity loss (VL) thresholds-0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)-on strength gains, neuromuscular adaptations, and muscle hypertrophy. METHODS Sixty-four resistance-trained young men were randomly assigned into four groups (VL0, VL15, VL25, and VL50) that differed in the VL allowed in each set. Subjects followed a VBT program for 8-weeks using the BP exercise. Before and after the VBT program the following tests were performed: (a) cross-sectional area (CSA) measurements of pectoralis major (PM) muscle; (b) maximal isometric test; (c) progressive loading test; and (d) fatigue test. RESULTS Significant group x time interactions were observed for CSA (P

The aim of this study was to compare the time course of recovery following four different resistance exercise protocols in terms of loading magnitude (60% vs. 80% 1RM&mdash, one-repetition maximum) and velocity loss in the set (20% vs. 40%). Seventeen males performed four different protocols in full squat exercise, which were as follows: (1) 60% 1RM with a velocity loss of 20% (60-20), (2) 60% 1RM with a velocity loss of 40% (60-40), (3) 80% 1RM with a velocity loss of 20% (80-20), and (4) 80% 1RM with a velocity loss of 40% (80-40). Movement velocity against the load that elicited a 1 m&middot, s&minus, 1 velocity at baseline measurements (V1-load), countermovement jump (CMJ) height, and sprint time at 20 m (T20) were assessed at Pre, Post, 6 h-Post, 24 h-Post, and 48 h-Post. Impairments in V1-load were significantly higher for 60-40 than other protocols at Post (p &lt, 0.05). The 60-20 and 80-40 protocols exhibited significant performance impairments for V1-load at 6 h-Post and 24 h-Post, respectively (p &lt, 0.05). CMJ height remained decreased for 60-20 and 60-40 until 24 h-Post (p &lt, 0.001&ndash, 0.05). Regarding T20, the 80-40 protocol resulted in higher performance than 60-40 at 24 h-Post and the 80-20 protocol induced a greater performance than 60-40 protocol at 48 h-Post (p &lt, 0.05). A higher velocity loss during the set (40%) and a lower relative load (60% 1RM) resulted in greater fatigue and slower rate of recovery than lower velocity loss (20%) and higher relative load (80% 1RM).