Inter-repetition Rest Research Articles

Inter-Repetition Rest Impact on the Estimated Repetitions in Reserve at Various Loads and Proximities to Neuromuscular Failure.

Ruiz-Alias, SA, Ramirez-Campillo, R, Leando Quidel-Catrilelbún, ME, García-Pinillos, F, and Pérez-Castilla, A. Inter-repetition rest impact on the estimated repetitions in reserve at various loads and proximities to neuromuscular failure . J Strength Cond Res 38(8): 1379-1385, 2024-The repetitions in reserve (RIR) estimation method allows for monitoring resistance training set volume. However, a significant bias is commonly observed when ending the set further from neuromuscular failure and using lower relative loads. Is unclear if implementing an IRR could improve its estimation validity. This study aimed to determine if the RIR estimation is influenced by the IRR at different relative loads and proximities to neuromuscular failure during the back squat (BQ) and bench press (BP) exercises. After a familiarization session, 19 male subjects (age, 21-26 years) completed an experimental session for each IRR configuration: IRR0 (without rest), IRR3 (3 seconds of rest), and SSIRR (self-selected rest [up to 5 seconds]). In each session, single sets to neuromuscular failure were performed at 3 relative loads (65% 1 repetition maximum [1RM], 75% 1RM, 85% 1RM) for BQ and BP exercises. Using the Estimated Repetitions to Failure scale, subjects estimated the RIR associated with a score of "5" and "2" (i.e., RIR-5 and RIR-2). The results revealed no interactions between the RIR estimation and IRR for BQ (RIR-5: p = 0.812; RIR-2: p = 0.084) or BP (RIR-5: p = 0.884; RIR-2: p = 0.944). Subjects provided valid estimations, with overestimation (BQ RIR-5: 0%; BQ RIR-2: 2.9%; BP RIR-5: 1.1%; BP RIR-2: 2.3%) or underestimation (BQ RIR-5: 14.9%; BQ RIR-2: 4%; BP RIR-5: 15.2% BP RIR-2: 8.2%) in few sets. In conclusion, the RIR estimation method seems valid, and the IRR (0-5 seconds) does not influence its validity at 65-85% 1RM loads nor proximities to neuromuscular failure (RIR-2, RIR-5).

Acute Effects of Different Inter-Repetition Rest Intervals During ‘Composite’ Training on Fast Stretch-Shortening Cycle and Neuromuscular Performance in Hurling Players: A Pilot Study

One study to date has compared inter-repetition rest intervals when employing ‘composite’ training. Thus, the purpose of this study was to compare the acute effects of 2-, 3- and 4-mins ‘composite’ training inter-repetition rest intervals on fast stretch shortening cycle (SSC) and neuromuscular performance. A randomized crossover research design was employed. Drop jump (DJ), 20m sprint (with 5 and 10m splits), countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) tests were performed pre-session, post-session, and 7 days post-session to observe if supercompensation occurred. A 2-min rest interval showed enhancements in fast SSC DJ performance where supercompensation may have occurred in height, velocity, force and power (Cohen’s d = 0.22-0.55). A 3-minute rest interval elicited responses in 5 and 20m sprint performance (Cohen’s d = -0.29 to -0.30) and isometric RFD (Cohen’s d = 0.35-0.60) 7 days post-session. CMJ measures (Cohen’s d = 0.22-0.76) appeared to have experienced supercompensation when employing a 4-minute rest period. Significant (p < 0.05) decreases in performance pre- to post-session were found for certain sprint, CMJ and IMTP variables. The ‘composite’ training inter-repetition rest interval used, appears dependent on the primary goal of a training cycle. However, a 3-min rest interval may be used if there are multiple goals of a training cycle due to enhancements in sprint performance, isometric RFD and CMJ height. ‘Composite’ training is a time-efficient method of enhancing jump, sprint, and maximal strength, which is suitable for practitioners working in sports such as hurling where time is limited.

Effects of Training Volume in the Bench-Press Exercise Performed With Interrepetition Rest Periods on Strength Gains and Neuromuscular Adaptations.

To investigate the effects of 3 training volumes in the bench-press exercise performed with interrepetition rest periods, matched for fatigue, on strength gains and neuromuscular adaptations. Forty-three resistance-trained men were randomized into 3 groups: low (LOW), moderate (MOD), and high (HIG) volume. The intensities increased from 70% to 85% of 1-repetition maximum (1RM) over the 8-week training period. Each session consisted of only 1 set with short interrepetition rest periods. LOW performed only 3 repetitions per session (8-wk total: 48 repetitions); MOD completed 15, 12, 10, and 8 repetitions per session with 70%, 75%, 80%, and 85% 1RM, respectively (8-wk total: 180); and HIG performed 24, 21, 18, and 15 repetitions per session with 70%, 75%, 80%, and 85% 1RM, respectively (8-wk total: 312). Progressive loading and fatigue tests were conducted in the bench-press exercise before and after the training period. Electromyography (EMG) signals from the triceps brachii were registered during these tests. HIG and MOD showed higher velocity loss than LOW (16% vs 12%). No significant group × time interaction was observed for any variable. All groups improved significantly in all strength-related variables, except for maximal unloaded velocity, where only MOD obtained significant gains. Only LOW and MOD induced significant improvements in EMG. MOD obtained the greatest effect sizes in almost all strength variables. No significant differences were found in the performance gains obtained by each group despite the wide differences in the total volume accumulated by each group.

Inter-repetition Rest Impact on Percentage of Repetition Completed at Certain Velocity Loss.

This study examined the impact of different inter-repetition rest (IRR) configurations (zero seconds [IRR0], three seconds [IRR3], and self-selected less than five seconds [SSIRR]) on estimating the number of repetitions (Nrep) and the percentage of completed repetitions relative to the maximum number of repetitions possible to failure (%rep) after reaching 10%, 20%, and 30% velocity loss thresholds (VLT). Eighteen men completed three sessions, each with a different IRR configuration, separated by 48-72 hours. Single sets of repetitions to momentary muscular failure were performed against 65%, 75%, and 85% of the one-repetition maximum during free-weight back squat and bench press exercises. No significant differences were reported between IRR configurations for the Nrep (P≥0.089) and %rep (P≥0.061), except for %rep after reaching the 20-30%VLT against 65%1RM and the 10-20%VLT against 75%1RM in the bench press exercise (P≤0.048). Additionally, both Nrep and %rep exhibited high interindividual variability (between-subject CV=14-79%) across the different IRR configurations. The individual %rep-%VLT relationships were slightly stronger than the general %rep-%VLT relationships (median R 2 =0.914-0.971 vs. 0.698-0.900). Overall, regardless of the IRR configuration, this novel velocity-based approach does not guarantee the same effort levels across subjects in the free-weight back squat and bench press sets.

Comparison in Repetitions to Failure Between Concentric-Only and Eccentric-Only Dumbbell Arm Curl Exercise at Four Different Relative Intensities.

Shibata, K, Yamaguchi, T, Takizawa, K, and Nosaka, K. Comparison in repetitions to failure between concentric-only and eccentric-only dumbbell arm curl exercise at four different relative intensities. J Strength Cond Res 37(9): 1754-1760, 2023-The repetitions to failure (RF) were compared between concentric-only (CON) and eccentric-only (ECC) arm curl exercise for different intensities based on CON and ECC 1 repetition maximum (1RM), respectively, with 2 different inter-repetition rests. Sixteen healthy male, university students (19-22 years) participated in 6 sessions. In sessions 1 and 2, CON and ECC 1RM strength were determined. In sessions 3 to 6, CON and ECC dumbbell arm curl exercises were performed until momentary failure at the intensity of either 70, 80, 90 or 95% of CON and ECC 1RM, respectively, with the inter-repetition rest of 3 seconds (R3) for one arm and 6 seconds (R6) for the other arm in a pseudo-randomized order. A significant ( p < 0.01) muscle contraction type × intensity interaction effect was evident for both R3 and R6 conditions. RF was greater ( p < 0.01) in ECC than in CON at 70% (34.2 ± 13.3 vs 20.9 ± 5.4), 80% (22.0 ± 6.7 vs 11.6 ± 2.7), 90% (10.1 ± 3.1 vs 5.2 ± 1.3), and 95% (6.8 ± 2.1 vs 2.7 ± 0.8) for R3. RF was also greater ( p < 0.01) for ECC than for CON at 80% (24.5 ± 8.1 vs 15.6 ± 3.6), 90% (10.8 ± 2.8 vs 7.2 ± 1.8) and 95% (6.7 ± 2.4 vs 3.9 ± 1.5) for R6, with greater ( p < 0.05) RF for R6 than R3. Significant ( p < 0.01) correlations in RF were evident between CON and ECC for R3 ( r = 0.86) and R6 ( r = 0.76). Equations to estimate 1RM were derived for CON and ECC at R3 and R6 (e.g., ECC 1RM = Load × 110.0/[110.5-RF] for R3). These results suggest that fatigue is less in ECC than in CON performed at the same relative intensity.

Acute Mechanical and Skin Temperature Responses to Different Interrepetition Rest Intervals During Full-Squat Exercise.

This study aimed to (1)evaluate the acute effects of different interrepetition rest full-squat protocols on countermovement jump (CMJ) height, velocity loss (VL), and skin temperature (Tsk) and (2)determine whether the VL, the changes in Tsk, or the individual strength level is associated with the change in CMJ height. Sixteen resistance-trained men randomly performed 3 squat protocols at maximal intended velocity with 60% of the 1-repetition maximum (sets × repetitions [interrepetition rest]): traditional (2 × 6 [0s]), cluster 2 (2 × 6 [30s every 2 repetitions]), and cluster 1 (1 × 12; [36s every repetition]), plus a control session. CMJ height was assessed before and 2, 4, and 8minutes after the protocols. There was a significant main effect of protocol for the VL (F = 20.54, P < .001) and loss in mean power (F = 12.85, P < .001; traditional > cluster 2 > cluster 1). However, we found a comparable reduction of CMJ height after 8minutes: traditional (-3.4% [4.2%]), cluster 2 (-5.3% [4.9%]), cluster 1 (-5.4% [2.9%]), and control (-4.2% [3.6%]). Overall, mean Tsk acutely decreased after all the protocols. Higher individual strength level (but not VL or the changes in Tsk) was associated with lower CMJ-height loss (P < .05). Although different interrepetition rest full-squat protocols may alter the loss in velocity and power, they result in a similar decrease in Tsk and CMJ height, which could be more influenced by individual strength level than VL or changes in Tsk.

Effect of High-Volume Cluster Sets vs. Lower-Volume Traditional Sets on Accuracy of Estimated Repetitions to Failure.

Davies, TB, Li, J, and Hackett, DA. Effect of high-volume cluster sets vs. lower-volume traditional sets on accuracy of estimated repetitions to failure. J Strength Cond Res 37(6): 1191-1198, 2023-This study investigated the effects of resistance training using cluster (CLUS) vs. traditional (TRAD) set structures on the accuracy of estimated repetitions to failure (ERF). Nineteen healthy male resistance trainers (age 21.0 ± 4.4 years) were randomized into 1 of the 2 bench press training routines performed for 6 weeks. Cluster ( n = 10) performed 6 sets of 5 repetitions at 85% of 1 repetition maximum (1RM) with 30-second interrepetition rest and 3 minutes of interset rest. Traditional ( n = 9) performed 3 sets of 5 repetitions at 85% 1RM with 5 minutes of interset rest. Maximum repetitions at 85% 1RM was performed before and after intervention to assess error in ERF and mean concentric velocity (MCV). The ERF, rating of perceived exertion, and maintenance of MCV were assessed throughout the intervention. Rating of perceived exertion was lower for sets 1-3 in CLUS compared with TRAD from weeks 1 to 4 (effect size [ES] = 0.8-2.4, p ≤ 0.04). The ERF was greater for sets 1-3 in CLUS than in TRAD during all intervention weeks (ES = 1.0-5.1, p ≤ 0.04). Maintenance of MCV was greater in CLUS compared with TRAD for all sets at week 1 (ES = 0.76, p = 0.002) and sets 4-6 at week 6 (ES = 0.77, p = 0.006). After the intervention, error in ERF did not change, and no differences were found between the groups. Findings indicate that accuracy of ERF does not improve after resistance training using set structures that induce different transient fatigue-related effects when using high loads in experienced resistance trainers.

Impact of Interrepetition Rest on Muscle Blood Flow and Exercise Tolerance during Resistance Exercise.

Background and Objectives: Muscle blood flow is impeded during resistance exercise contractions, but immediately increases during recovery. The purpose of this study was to determine the impact of brief bouts of rest (2 s) between repetitions of resistance exercise on muscle blood flow and exercise tolerance. Materials and Methods: Ten healthy young adults performed single-leg knee extension resistance exercises with no rest between repetitions (i.e., continuous) and with 2 s of rest between each repetition (i.e., intermittent). Exercise tolerance was measured as the maximal power that could be sustained for 3 min (PSUS) and as the maximum number of repetitions (Reps80%) that could be performed at 80% one-repetition maximum (1RM). The leg blood flow, muscle oxygenation of the vastus lateralis and mean arterial pressure (MAP) were measured during various exercise trials. Alpha was set to p ≤ 0.05. Results: Leg blood flow was significantly greater, while vascular resistance and MAP were significantly less during intermittent compared with continuous resistance exercise at the same power outputs (p < 0.01). PSUS was significantly greater during intermittent than continuous resistance exercise (29.5 ± 2.1 vs. 21.7 ± 1.2 W, p = 0.01). Reps80% was also significantly greater during intermittent compared with continuous resistance exercise (26.5 ± 5.3 vs. 16.8 ± 2.1 repetitions, respectively; p = 0.02), potentially due to increased leg blood flow and muscle oxygen saturation during intermittent resistance exercise (p < 0.05). Conclusions: In conclusion, a brief rest between repetitions of resistance exercise effectively decreased vascular resistance, increased blood flow to the exercising muscle, and increased exercise tolerance to resistance exercise.

Changes in joint kinematics and kinetics through the implementation of inter-repetition rest protocols in snatch training

Background and Study Aim. Inter-repetition rest pertains to a short period of rest between repetitions during strength training. Manipulating inter-repetition rest may influence fatigue accumulation, manifesting alteration in lifting mechanics. This study aimed to examine the effects of different inter-repetition rest protocols on joint velocity and ground reaction force during snatch exercise.&#x0D; Material and Methods. Fifteen male (n=15) athletes participated in this study (age = 23.0 ±2.31 years; body weight = 65.32 ± 1.37 kg; height = 168.80 ± 5.64 cm; snatch one repetition maximum (1RM)/bodyweight = 0.78 ± 0.12), performing three sets of 5 repetitions at 85% 1 Repetition Maximum snatch with 10, 30, or 50 seconds of inter-repetition rest implemented randomly across three sessions. Ankle, knee, and hip kinematics and ground reaction force in the three protocols were used for comparison. The participants visited the exercise science laboratory for four sessions between 0800-1700 hrs. These sessions were separated by 72 hours.&#x0D; Results. One-way repeated measure analysis of variances (ANOVA) showed a significant effect of inter-repetition rest on the maintenance of kinematic and kinetic variables. The ground reaction force for 10 seconds inter-repetition rest protocol showed a significant drop in force output across repetition (p = .037, p &lt; 0.05).&#x0D; Conclusions. The utilization of inter-repetition rest in snatch exercise may reduce neuromuscular fatigue across repetitions, maintaining consistent performance output. Specifically, the 50 second inter-repetition rest protocol reduced the negative effect of neuromuscular fatigue in the kinematic and kinetic variables during snatch exercise.

Effect of Inter-Repetition Rest Vs. Traditional Resistance Training on The Upper Body Strength Rate of Force Development and Triceps Brachii Muscle Architecture.

The purpose of the study was to examine the effect of seven-week inter-repetition rest vs. traditional resistance training on upper body maximum strength, the rate of force development and triceps brachii muscle architecture. Sixteen male participants were equally assigned into the inter-repetition rest and the traditional group. In both groups, training included the bench press exercise performed with 4 sets of 6 maximum repetitions, two training sessions per week. Twenty-second inter-repetition rest was employed for the inter-repetition rest group only. Measurements before and after the training period included maximum strength in the bench press, the isometric upper body rate of force development and peak force and triceps brachii muscle architecture. Maximum strength increased significantly in both groups (inter-repetition rest group: 21.5 ± 5.7% vs. traditional group: 13.5 ± 7.2%, p < 0.05), however, the maximum strength percentage increase was greater in the inter-repetition rest group compared to the traditional group (p = 0.027). Upper body isometric peak force increased only after inter-repetition rest training (10.7 ± 10.3%, p = 0.009). The rate of force development remained unchanged for both groups (p > 0.05), although percentage changes in time frames of 0-80 and 0-100 milliseconds were greater for the inter-repetition rest group compared to the traditional training group (p = 0.024 and p = 0.044, respectively). Triceps brachii thickness increased similarly for both groups (p < 0.05). These results suggest that inter-repetition rest may induce greater increases in maximum strength and the rate of force development compared to traditional training during the initial weeks of resistance training.

The Effect of Inter-Repetition Rest Duration on Kinematic of Snatch

The Effect of Inter-Repetition Rest Duration on Kinematic of Snatch

Acute Effects of Parallel Back Squat Performed in Different Set Configurations on Neuromuscular Performance.

We compared the acute effects of parallel back squat performed from different resistance training configurations on neuromuscular performance. Twenty-eight young adults underwent 4 experimental conditions: inter-repetition rest, traditional, traditional to failure, and rest-pause in the parallel back squat in a randomized, counterbalanced, and cross-over design. The neuromuscular performance was assessed through peak torque of knee extensors and flexors at two angular velocities (90 and 120 º/s) in three moments (before, post, and post-30 min). The peak torque of the knee extensors and flexors at 90 and 120 º/s decreased immediately after training for traditional, traditional to failure, and rest-pause (-8.1% to -17.7%, P<0.001). A greater reduction in the extensor peak torque was found at 120 º/s (P<0.05) in the rest-pause (-17.7%) when compared to traditional (-10.8%). The peak torque returned to baseline values only at post-30 min for the traditional configuration for the knee flexion action at 120 º/s. The peak torque remained similar for the muscular actions and angular velocities for the inter-repetition rest (P>0.05). Our results suggest the inter-repetition rest configuration seems to be a more appropriate strategy for maintaining the lower limb neuromuscular performance after a resistance training session.

Strengthening the Case for Cluster Set Resistance Training in Aged and Clinical Settings: Emerging Evidence, Proposed Benefits and Suggestions.

Resistance training (RT) is a fundamental component of exercise prescription aimed at improving overall health and function. RT techniques such as cluster set (CS) configurations, characterized by additional short intra-set or inter-repetition rest intervals, have been shown to maintain acute muscular force, velocity, and 'power' outputs across a RT session, and facilitate positive longer-term neuromuscular adaptations. However, to date CS have mainly been explored from a human performance perspective despite potential for application in health and clinical exercise settings. Therefore, this current opinion piece aimsto highlight emerging evidence and provide a rationale for why CS may be an advantageous RT technique for older adults, and across several neurological, neuromuscular, cardiovascular and pulmonary settings. Specifically, CS may minimize acute fatigue and adverse physiologic responses, improve patient tolerance of RT and promote functional adaptations (i.e., force, velocity, and power). Moreover, we propose that CS may be a particularly useful exercise rehabilitation technique where injury or illness, persistent fatigue, weakness and dysfunction exist. We further suggest that CS offer an alternative RT strategy that can be easily implemented alongside existing exercise/rehabilitation programs requiring no extra cost, minimal upskilling and/or time commitment for the patient and professional. In light of the emerging evidence and likely efficacy in clinical exercise practice, future research should move toward further direct investigation of CS-based RT in a variety of adverse health conditions and across the lifespan given the already demonstrated benefits in healthy populations.

Effect of Set-Structure on Upper-Body Muscular Hypertrophy and Performance in Recreationally-Trained Male and Female.

Davies, TB, Halaki, M, Orr, R, Mitchell, L, Helms, ER, Clarke, J, and Hackett, DA. Effect of set structure on upper-body muscular hypertrophy and performance in recreationally trained men and women. J Strength Cond Res 36(8): 2176-2185, 2022-This study explored the effect of volume-equated traditional-set and cluster-set structures on muscular hypertrophy and performance after high-load resistance training manipulating the bench press exercise. Twenty-one recreationally trained subjects (12 men and 9 women) performed a 3-week familiarization phase and were then randomized into one of two 8-week upper-body and lower-body split programs occurring over 3 and then progressing to 4 sessions per week. Subjects performed 4 sets of 5 repetitions at 85% one repetition maximum (1RM) using a traditional-set structure (TRAD, n = 10), which involved 5 minutes of interset rest only, or a cluster-set structure, which included 30-second inter-repetition rest and 3 minutes of interset rest (CLUS, n = 11). A 1RM bench press, repetitions to failure at 70% 1RM, regional muscle thickness, and dual-energy x-ray absorptiometry were used to estimate changes in muscular strength, local muscular endurance, regional muscular hypertrophy, and body composition, respectively. Velocity loss was assessed using a linear position transducer at the intervention midpoint. TRAD demonstrated a significantly greater velocity loss magnitude (g = 1.50) and muscle thickness of the proximal pectoralis major (g = -0.34) compared with CLUS. There were no significant differences between groups for the remaining outcomes, although a small effect size favoring TRAD was observed for the middle region of the pectoralis major (g = -0.25). It seems that the greater velocity losses during sets observed in traditional-set compared with cluster-set structures may promote superior muscular hypertrophy within specific regions of the pectoralis major in recreationally trained subjects.

Effect of Set-Structure on Upper-Body Muscular Hypertrophy and Performance in Recreationally-Trained Male and Female.

Davies, TB, Halaki, M, Orr, R, Mitchell, L, Helms, ER, Clarke, J, and Hackett, DA. Effect of set structure on upper-body muscular hypertrophy and performance in recreationally trained men and women. J Strength Cond Res XX(X): 000-000, 2021-This study explored the effect of volume-equated traditional-set and cluster-set structures on muscular hypertrophy and performance after high-load resistance training manipulating the bench press exercise. Twenty-one recreationally trained subjects (12 men and 9 women) performed a 3-week familiarization phase and were then randomized into one of two 8-week upper-body and lower-body split programs occurring over 3 and then progressing to 4 sessions per week. Subjects performed 4 sets of 5 repetitions at 85% one repetition maximum (1RM) using a traditional-set structure (TRAD, n = 10), which involved 5 minutes of interset rest only, or a cluster-set structure, which included 30-second inter-repetition rest and 3 minutes of interset rest (CLUS, n = 11). A 1RM bench press, repetitions to failure at 70% 1RM, regional muscle thickness, and dual-energy x-ray absorptiometry were used to estimate changes in muscular strength, local muscular endurance, regional muscular hypertrophy, and body composition, respectively. Velocity loss was assessed using a linear position transducer at the intervention midpoint. TRAD demonstrated a significantly greater velocity loss magnitude (g = 1.50) and muscle thickness of the proximal pectoralis major (g = -0.34) compared with CLUS. There were no significant differences between groups for the remaining outcomes, although a small effect size favoring TRAD was observed for the middle region of the pectoralis major (g = -0.25). It seems that the greater velocity losses during sets observed in traditional-set compared with cluster-set structures may promote superior muscular hypertrophy within specific regions of the pectoralis major in recreationally trained subjects.

Effect of Inter-Repetition Rest vs. Traditional Strength Training on Lower Body Strength, Rate of Force Development, and Muscle Architecture

The purpose of the study was to investigate the effect of seven weeks inter-repetition rest vs. traditional strength training on lower body strength, rate of force development (RFD), and vastus lateralis (VL) muscle architecture. Sixteen male participants were assigned into two groups: the inter-repetition rest (IRRG) and the traditional (TG) group. Both groups performed the leg press exercise with four sets of six maximum repetitions (RM) for two training sessions per week. IRRG added a 20 s inter-repetition rest period between single repetitions. Before and after the training period, 1-RM in leg press, isometric leg press RFD, and peak force (PF), VL muscle architecture, vastus intermedius (VI) thickness, and quadriceps’ cross sectional area (CSA) with ultrasonography, were measured. Two way ANOVA for repeated measures was used for statistics. One-RM strength increased similarly for both groups (p &lt; 0.05), while percentage increases in RFD were greater for IRRG compared to TG (p &lt; 0.05). Isometric PF was increased similarly for both groups (p &lt; 0.05). VL and VI thickness as well as CSA of the quadriceps increased similarly in both groups, while VL fascicle length increased more following IRRG compared to TG (IRRG: 4.8 ± 6.1% vs. TG: −3.9 ± 5.4%, p = 0.001). These results suggest that 20 s inter-repetition rest during strength training may effectively increase lower body explosive strength and muscle fascicle length without compromising muscle hypertrophy.

Effect of Resistance-Training Programs Differing in Set Configuration on Maximal Strength and Explosive-Action Performance.

To compare the effects of 2 upper-body strength-training programs differing in set configuration on bench press 1-repetition maximum (BP1RM), bench press throw peak velocity against 30kg (BPT30), and handball throwing velocity. Thirty-five men were randomly assigned to a traditional group (TRG; n = 12), rest redistribution group (RRG; n = 13), or control group (n = 10). The training program was conducted with the bench press exercise and lasted 6 weeks (2 sessions per week): TRG-6 sets × 5 repetitions with 3minutes of interset rest; RRG-1 set × 30 repetitions with 31seconds of interrepetition rest. The total rest period (15min) and load intensity (75% 1RM) were the same for both experimental groups. Subjects performed all repetitions at maximal intended velocity, and the load was adjusted on a daily basis from velocity recordings. A significant time × group interaction was observed for both BP1RM and BPT30 (P < .01) due to the higher values observed at posttest compared with pretest for TRG (effect size [ES] = 0.77) and RRG (ES = 0.56-0.59) but not for the control group (ES ≤ 0.08). The changes in BP1RM and BPT30 did not differ between TRG and RRG (ES = 0.04 and 0.05, respectively). No significant differences in handball throwing velocity were observed between the pretest and posttest (ES = 0.16, 0.22, and 0.02 for TRG, RRG, and control group, respectively). Resistance-training programs based on not-to-failure traditional and rest redistribution set configurations induce similar changes in BP1RM, BPT30, and handball throwing velocity.

Effect of 2- vs. 3-Minute Interrepetition Rest Period on Maximal Clean Technique and Performance.

Ammar, A, Riemann, BL, Abdelkarim, O, Driss, T, and Hökelmann, A. Effect of 2- vs. 3-minute interrepetition rest period on maximal clean technique and performance. J Strength Cond Res 34(9): 2548-2556, 2020-Currently, it is widely accepted that adopting a long rest period (3-5 minutes) during maximal strength and power exercise is of importance in reducing acute fatigue and maintaining power and technique proficiency. However, despite the fact that weightlifting is an example of maximal strength exercise, only 2 minutes are officially allowed when athletes attempt 2 successive lifts. The purpose of this study was to compare 3- vs. 2-minute intermaximal repetition rest periods (IMRRPs) on performance, rate of perceived exertion (RPE), technical efficiency, and power production during 2 successive maximal repetitions of clean & jerk (C&J). Nine elite weightlifters (age: 24.4 ± 3.6 years, body mass: 77.2 ± 7.1 kg, height 176.0 ± 6.4 cm, and 1 repetition maximum C&J: 170.0 ± 5.0 kg) performed 2 separate testing sessions using 2-minute IMRRP (IMRRP-2) and 3-minute IMRRP (IMRRP-3), in a randomized order, while barbell kinematics and kinetics were recorded. Results showed that the longer IMRRP-3 minutes led to the maintenance of clean technique (from the first to the second repetition) evidenced by a 1.86% lower decline in peak vertical displacement (p = 0.03) and attenuation of increased peak horizontal displacements with a 1.74% (p = 0.03) less backward movement during the first pull, a 3.89% (p = 0.008) less forward movement during the second pull, and a 4.7% (p = 0.005) less backward movement during the catch phase. In addition, attenuation of peak velocity (2.22%; p = 0.02), peak vertical ground reaction force (1.70%; p = 0.03), and peak power (2.14%; p = 0.02) declines were shown using IMRRP-3 compared with IMRRP-2. Increasing IMRRP from 2 to 3 minutes was also shown to decrease RPE values (8.02%; p = 0.008) and to enhance supramaximal C&J performance (1.55%; p = 0.003). The results of this study suggest 3 minutes to be the most advantageous IMRRP in terms of maintaining technical efficiency, power output, reducing fatigue perception, and enhancing performance in elite weightlifters.

Parasympathetic Nervous Activity Responses to Different Resistance Training Systems.

The assessment of parasympathetic nervous activity and psychophysiological responses infers the stress imposed by different resistance training systems. Therefore, we compare the effects of different sets configurations, with similar volume (~60 repetitions), on heart rate variability indices and internal training load. Twenty-nine resistance-trained adults completed the following conditions: traditional without and with muscle failure, inter-repetition rest, and rest-pause in the parallel squat. The heart rate variability indices (time-domain) were measured before and 30 min after each condition. The internal training load was obtained through the session-rating of perceived exertion method. Except for inter-repetition rest, all conditions reduced the heart rate variability indices after the session (P<0.05), and the rest-pause triggered the higher reductions (≤-46.7%). The internal training load was higher in the rest-pause (≤68.9%). Our results suggest that rest-pause configuration leads to more considerable disruption of the parasympathetic nervous activity and higher internal training load in trained adults. In contrast, inter-repetition rest allows lower autonomic and psychophysiological stress.

Counterpoint: Investigators should not control for menstrual cycle phase when performing studies of vascular control that include women.

Observed sex differences in the epidemiology of cardiovascular disease incidence and the efficacy of clinical intervention strategies, coupled with recent mandates from the National Institutes of Health (NIH), and its international counterparts to consider sex as a biological variable in all preclinical and clinical work (15), have led to increased enrollment of women in human physiology studies of vascular function with the goal of improving external validity and clinical applicability of the findings. However, standard practice in these studies is to test women during the early follicular phase (~days 1-5) of the menstrual cycle, during which estrogen and progesterone concentrations are lowest, and either exclude or limit testing of women who use hormonal contraceptives to the placebo phase. This approach seeks to control for, or limit, differences in circulating hormone concentrations between men and women and is based on the dogmatic theory that cyclic changes in estrogen and progesterone concentrations lead to greater variability in study outcomes and uninterpretable datasets. Contrary to this common approach, we propose that limiting testing of women to this single phase 1) decreases external validity of the findings, 2) obfuscates potential physiological differences contributable to differences in sex hormone concentrations between men and women, and 3) is, in many instances, contradicted by literature that demonstrates limited or no variability in vascular measurements across the menstrual cycle.