Prediction of One Repetition Maximum in Free-Weight Back Squat Using a Mixed Approach: The Combination of the Individual Load-Velocity Profile and Generalized Equations.

ABSTRACT: Fitas, A, Santos, P, Gomes, M, Pezarat-Correia, P, Schoenfeld, BJ, and Mendonca, GV. Prediction of one repetition maximum in free-weight back squat using a mixed approach: the combination of the individual load-velocity profile and generalized equations. J Strength Cond Res 38(2): 228-235, 2024-We aimed to develop a mixed methods approach for 1 repetition maximum (1RM) prediction based on the development of generalized equations and the individual load-velocity profile (LVP), and to explore the validity of such equations for 1RM prediction. Fifty-seven young men volunteered to participate. The submaximal load-velocity relationship was obtained for the free-weight parallel back squat. The estimated load at 0 velocity (LD0) was used as a single predictor, and in combination with the slope of the individual LVP, to develop equations predictive of 1RM. Prediction accuracy was determined through the mean absolute percent error and Bland-Altman plots. LD0 was predictive of 1RM ( p < 0.0001), explaining 70.2% of its variance. Adding the slope of the LVP to the model increased the prediction power of 1RM to 84.4% ( p < 0.0001). The absolute percent error between actual and predicted 1RM was lower for the predictions combining LD0 and slope (6.9 vs. 9.6%). The mean difference between actual and estimated 1RM was nearly zero and showed heteroscedasticity for the LD0 model, but not for the combined model. The limits of agreement error were of 31.9 and 23.5 kg for LD0 and LD0 combined with slope, respectively. In conclusion, the slope of the individual LVP adds predictive value to LD0 in 1RM estimation on a group level and avoids error trends in the estimation of 1RM over the entire spectrum of muscle strength. However, the use of mixed methods does not reach acceptable accuracy for 1RM prediction of the free-weight back squat on an individual basis.

Determining Changes in Muscle Size and Architecture After Exercise Training: One Site Does Not Fit all.

ABSTRACT: Nunes, JP, Blazevich, AJ, Schoenfeld, BJ, Kassiano, W, Costa, BDV, Ribeiro, AS, Nakamura, M, Nosaka, K, and Cyrino, ES. Determining changes in muscle size and architecture after exercise training: One site does not fit all. J Strength Cond Res 38(4): 787-790, 2024-Different methods can be used to assess muscle hypertrophy, but the effects of training on regional changes in muscle size can be detected only using direct muscle measurements such as muscle thickness, cross-sectional area, or volume. Importantly, muscle size increases vary across regions within and between muscles after resistance training programs (i.e., heterogeneous, or nonuniform, muscle hypertrophy). Muscle architectural changes, including fascicle length and pennation angle, after resistance and stretch training programs are also region-specific. In this paper, we show that the literature indicates that a single-site measure of muscle shape does not properly capture the effects achieved after exercise training interventions and that conclusions concerning the magnitude of muscle adaptations can vary substantially depending on the muscle site to be examined. Thus, we propose that measurements of muscle size and architecture should be completed at multiple sites across regions between the agonist muscles within a muscle group and along the length of the muscles to provide an adequate picture of training effects.

Do Muscle Mass and Body Fat Differ Between Elite and Amateur Natural Physique Athletes on Competition Day? A Preliminary, Cross-Sectional, Anthropometric Study.

ABSTRACT: González-Cano, H, Martín-Olmedo, JJ, Baz-Valle, E, Contreras, C, Schoenfeld, BJ, García-Ramos, A, Jiménez-Martínez, P, and Alix-Fages, C. Do muscle mass and body fat differ between elite and amateur natural physique athletes on competition day? A preliminary, cross-sectional, anthropometric study. J Strength Cond Res 38(5): 951-956, 2024-Natural physique athletes strive to achieve low body fat levels while promoting muscle mass hypertrophy for competition day. This study aimed to compare the anthropometric characteristics of natural amateur (AMA) and professional (PRO) World Natural Bodybuilding Federation (WNBF) competitors. Eleven male natural physique athletes (6 PRO and 5 AMA; age = 24.8 ± 2.3 years) underwent a comprehensive anthropometric evaluation following the International Society for the Advancement of Kinanthropometry protocol within a 24-hour time frame surrounding the competition. The 5-component fractionation method was used to obtain the body composition profile of the muscle, adipose, bone, skin, and residual tissues. Five physique athletes exceeded the 5.2 cutoff point of muscle-to-bone ratio (MBR) for natural athletes. Professional physique athletes were older than AMA physique athletes (p = 0.05), and they also presented larger thigh girths (p = 0.005) and bone mass (p = 0.019) compared with AMA physique athletes. Although no statistically significant between-group differences were observed in body mass, height, or body fat levels, PRO physique athletes exhibited a higher body mass index (BMI; AMA: 24.45 ± 0.12; PRO: 25.52 ± 1.01; p = 0.048), lean body mass (LBM; AMA: 64.49 ± 2.35; PRO: 69.80 ± 3.78; p = 0.024), fat-free mass (FFM; AMA: 71.23 ± 3.21; PRO: 76.52 ± 4.31; p = 0.05), LBM index (LBMI; AMA: 20.65 ± 0.52; PRO: 21.74 ± 0.85; p = 0.034), and fat-free mass index index (FFMI; AMA: 22.80 ± 0.22; PRO: 23.83 ± 0.90; p = 0.037) compared with AMA physique athletes. These findings highlight the unique characteristics and anthropometric differences between PRO and AMA natural physique athletes on competition day, emphasizing the significance of age, thigh girth, bone mass, BMI, LBM, FFM, and FFMI in distinguishing these 2 groups. Based on our findings, the established boundaries for muscle mass in natural physique athletes, based on FFMI and MBR, warrant reconsideration.

Resistance training volume does not influence lean mass preservation during energy restriction in trained males.

This study investigated the effects of a relatively high- versus moderate-volume resistance training program on changes in lean mass during caloric restriction. Thirty-eight resistance-trained males were randomized to perform either a high-volume (HVG; 5 sets/exercise) or a moderate-volume (MVG; 3 sets/exercise) resistance training program. Both groups were supervised during lower body training. Participants consumed 30 kcal/kg for 6 weeks after 1 week of weight maintenance (45 kcal/kg), with protein intake fixed at 2.8 g/kg fat-free mass. Muscle thickness of the m. rectus femoris, body composition, contractile properties, stiffness, mood, and sleep status were assessed at pre-, mid-, and post-study. No significant group × time interaction was observed for muscle thickness of the m. rectus femoris at 50% (∆ [post-pre] 0.36 ± 0.93 mm vs. ∆ -0.01 ± 1.59 mm; p = 0.226) and 75% length (∆ -0.32 ± 1.12 mm vs. ∆ 0.08 ± 1.14 mm; p = 0.151), contractility, sleep, and mood in the HVG and MVG, respectively. Body mass (HVG: ∆ -1.69 ± 1.12 kg vs. MVG: ∆ -1.76 ± 1.76 kg) and lean mass (∆ -0.51 ± 2.30 kg vs. ∆ -0.92 ± 1.59 kg) decreased significantly in both groups (p = 0.022), with no between-group difference detected (p = 0.966). High-volume resistance training appears to have neither an advantage nor disadvantage over moderate-volume resistance training in terms of maintaining lean mass or muscle thickness. Given that both groups increased volume load and maintained muscle contractility, sleep quality, and mood, either moderate or higher training volumes conceivably can be employed by resistance-trained individuals to preserve muscle during periods of moderate caloric restriction.

Efficacy of progressive versus severe energy restriction on body composition and strength in concurrent trained women.

PURPOSE: This study evaluated the concurrent training (CT) effect in combination with either progressive energy restriction (PER) or severe energy restriction (SER) on body composition and strength-related variables in resistance-trained women. METHODS: Fourteen women (29.5 ± 3.8 years; 23.8 ± 2.8 kg·m-2) were randomly assigned to a PER (n = 7) or SER (n = 7) group. Participants performed an 8-week CT program. Pre- and post-intervention measures of fat mass (FM) and fat-free mass (FFM) were assessed by dual-energy X-ray absorptiometry and strength-related variables were assessed through 1-repetition maximum (in the squat and bench press) and countermovement jump. RESULTS: Significant reductions in FM were observed in PER and SER (Δ = - 1.7 ± 0.4 kg; P = < 0.001; ES = - 0.39 and Δ = - 1.2 ± 0.6 kg; P = 0.002; ES = - 0.20, respectively). After correcting FFM for fat-free adipose tissue (FFAT), no significant differences for this variable were found either in PER (Δ = - 0.3 ± 0.1; P = 0.071; ES = - 0.06) or in SER (Δ = - 0.2 ± 0.1; P = 0.578; ES = - 0.04). There were no significant changes in the strength-related variables. No between-group differences were found in any of the variables. CONCLUSION: A PER has similar effects to a SER on body composition and strength in resistance-trained women performing a CT program. Given that PER is more flexible and thus may enhance dietary adherence, it might be a better alternative for FM reduction compared to SER.

Meta-analysis of variation in sport and exercise science: Examples of application within resistance training research.

Meta-analysis has become commonplace within sport and exercise science for synthesising and summarising empirical studies. However, most research in the field focuses upon mean effects, particularly the effects of interventions to improve outcomes such as fitness or performance. It is thought that individual responses to interventions vary considerably. Hence, interest has increased in exploring precision or personalised exercise approaches. Not only is the mean often affected by interventions, but variation may also be impacted. Exploration of variation in studies such as randomised controlled trials (RCTs) can yield insight into interindividual heterogeneity in response to interventions and help determine generalisability of effects. Yet, larger samples sizes than those used for typical mean effects are required when probing variation. Thus, in a field with small samples such as sport and exercise science, exploration of variation through a meta-analytic framework is appealing. Despite the value of embracing and exploring variation alongside mean effects in sport and exercise science, it is rarely applied to research synthesis through meta-analysis. We introduce and evaluate different effect size calculations along with models for meta-analysis of variation using relatable examples from resistance training RCTs.

Supervision during resistance training positively influences muscular adaptations in resistance-trained individuals.

This study compared the effects of supervised versus unsupervised resistance training (RT) on measures of muscle strength and hypertrophy in resistance-trained individuals. Thirty-six young men and women were randomly assigned to one of two experimental, parallel groups to complete an 8-week RT programme: One group received direct supervision for their RT sessions (SUP); the other group performed the same RT programme in an unsupervised manner (UNSUP). Programme variables were kept constant between groups. We obtained pre- and post-study assessments of body composition via multi-frequency bioelectrical impedance analysis (MF-BIA), muscle thickness of the upper and lower limbs via ultrasound, 1 repetition maximum (RM) in the back squat and bench press, isometric knee extension strength, and countermovement jump (CMJ) height. Results showed the SUP group generally achieved larger increases in muscle thickness for the triceps brachii, all sites of the rectus femoris, and the proximal region of the vastus lateralis. MF-BIA indicated increases in lean mass favoured SUP. Squat 1RM was greater for SUP; bench press 1RM and isometric knee extension were similar between conditions. CMJ increases modestly favoured UNSUP. In conclusion, our findings suggest that supervised RT promotes greater muscular adaptations and enhances exercise adherence in young, resistance-trained individuals.

Nutrition, Training, Supplementation, and Performance-Enhancing Drug Practices of Male and Female Physique Athletes Peaking for Competition.

ABSTRACT: Escalante, G, Barakat, C, Tinsley, GM, and Schoenfeld, BJ. Nutrition, training, supplementation, and performance-enhancing drug practices of male and female physique athletes peaking for competition. J Strength Cond Res 37(8): e444-e454, 2023-The purpose of this descriptive investigation was threefold: (a) to assess the nutrition, training, supplement, and performance-enhancement drug practices of male and female physique competitors 30 days before competition; (b) to examine the specific water and macronutrient manipulation performed by competitors during the last 3 days before competition; and (c) to assess physiological responses to precontest preparation including body composition, body fluids, resting heart rate, and blood pressure. Competitors reported performing moderately high volume, moderate to high repetition, split-body resistance training programs performed on most days of the week; the programs included the use of a variety of advanced training methods. A majority of competitors included cardio to expedite fat loss, and most reported performing cardio in a fasted state despite a lack of objective evidentiary support for the practice. Competitors substantially restricted calories and consumed protein in amounts well above research-based guidelines (>3 g·kg -1 ·d -1 ); carbohydrate and lipid intake were highly variable. Water was substantially reduced in the final 3 days before competition. Competitors used a variety of dietary supplements throughout the study period, many of which are not supported by research. Both male and female competitors reported using performance enhancing drugs (∼48 and ∼38%, respectively) including testosterone derivatives, selective androgen receptor modulators, and human growth hormone. More research is warranted to elucidate safer and more effective peak week practices for physique competitors.

Repetition Performance, Rating of Perceived Discomfort, and Blood Lactate Responses to Different Rest Interval Lengths in Single-Joint and Multijoint Lower-Body Exercise.

ABSTRACT: Rosa, A, Coleman, M, Haun, C, Grgic, J, and Schoenfeld, BJ. Repetition performance, rating of perceived discomfort, and blood lactate responses to different rest interval lengths in single-joint and multijoint lower-body exercise. J Strength Cond Res 37(7): 1350-1357, 2023-The purpose of this study was to examine the effects of different rest interval lengths (RILs) on repetition performance, rating of discomfort, and blood lactate responses during lower-body single-joint and multijoint exercises. This study used a counterbalanced design where each subject performed the Smith machine back squat (BS) and leg extension (LE) using 3 different RIL configurations (1, 2, and 3 minutes) in a randomized fashion. Data collection occurred over the span of 3 separate days. Volunteers were randomly allocated to perform the independent variables (RILs and exercises) in 1 of 12 potential configurations. The initial session was allotted for familiarization with the rating of discomfort scale and 10 repetition maximum testing. The other 2 sessions involved training with the different configurations of RIL length using both the BS and LE. Randomization ensured that the BS was performed first in one of the training sessions and the LE was performed first in the other session. Results indicated that longer RILs had a small positive effect on repetition performance, with longer rest durations allowing for more repetitions compared with shorter durations. The largest difference in repetition performance between RILs was observed between 1 minute and 2-3 minutes rest; there were trivial differences in repetition performance between 2 and 3 minutes rest for both the BS and LE. Blood lactate levels were slightly higher with longer RILs. Overall, BS showed greater increases in blood lactate compared with LE, and these differences were magnified over time. Exercise selection and RIL both influenced rating of discomfort, with LE producing less discomfort than BS and longer RILs reducing perceived discomfort. Our findings suggest that RIL influences the repetition performance, blood lactate, and rating of discomfort responses between single-joint and multijoint exercises.

Which ROMs Lead to Rome? A Systematic Review of the Effects of Range of Motion on Muscle Hypertrophy.

ABSTRACT: Kassiano, W, Costa, B, Nunes, JP, Ribeiro, AS, Schoenfeld, BJ, and Cyrino, ES. Which ROMs lead to Rome? a systematic review of the effects of range of motion on muscle hypertrophy. J Strength Cond Res 37(5): 1135-1144, 2022-Resistance exercise range of motion (ROM) influences muscular adaptations. However, there are no consistent practical guidelines about the optimal ROM for maximizing muscle hypertrophy. The objective of this article was to systematically review the literature for studies that compared the effects of full ROM (fROM) and partial ROM (pROM) on muscle hypertrophy. PubMed/MEDLINE, Scopus, and Web of Science databases were searched to identify articles from the earliest record up to and including April 2022. We calculated the effect size (ES) scores of the variables of interest. Eleven studies were included in the review. Full ROM and pROM performed in the initial part of the ROM elicited greater muscle hypertrophy of the rectus femoris, vastus lateralis, biceps brachii, and brachialis distal sites (between-groups ES: 0.20-0.90) than pROM performed in the final part of the ROM. fROM elicited greater muscle growth on the gluteus maximus and adductors than pROM in the final part of the ROM (between-groups ES: 0.24-0.25). Initial pROM produced more favorable proximal rectus femoris hypertrophy than fROM (between-groups ES: 0.35-0.38). pROM in the middle part of the ROM elicited greater triceps brachii hypertrophy than fROM (between-group ES: 1.21). In conclusion, evidence suggests that when training at a longer muscle length-through either pROM or fROM-some muscles, such as quadriceps femoris, biceps brachii, and triceps brachii, tend to experience optimal growth. Thus, the use pROM in the initial part of the excursion in combination with fROM training should be considered when prescribing hypertrophy-oriented resistance training programs.

Maximizing Strength: The Stimuli and Mediators of Strength Gains and Their Application to Training and Rehabilitation.

ABSTRACT: Spiering, BA, Clark, BC, Schoenfeld, BJ, Foulis, SA, and Pasiakos, SM. Maximizing strength: the stimuli and mediators of strength gains and their application to training and rehabilitation. J Strength Cond Res 37(4): 919-929, 2023-Traditional heavy resistance exercise (RE) training increases maximal strength, a valuable adaptation in many situations. That stated, some populations seek new opportunities for pushing the upper limits of strength gains (e.g., athletes and military personnel). Alternatively, other populations strive to increase or maintain strength but cannot perform heavy RE (e.g., during at-home exercise, during deployment, or after injury or illness). Therefore, the purpose of this narrative review is to (a) identify the known stimuli that trigger gains in strength; (b) identify the known factors that mediate the long-term effectiveness of these stimuli; (c) discuss (and in some cases, speculate on) potential opportunities for maximizing strength gains beyond current limits; and (d) discuss practical applications for increasing or maintaining strength when traditional heavy RE cannot be performed. First, by conceptually deconstructing traditional heavy RE, we identify that strength gains are stimulated through a sequence of events, namely: giving maximal mental effort, leading to maximal neural activation of muscle to produce forceful contractions, involving lifting and lowering movements, training through a full range of motion, and (potentially) inducing muscular metabolic stress. Second, we identify factors that mediate the long-term effectiveness of these RE stimuli, namely: optimizing the dose of RE within a session, beginning each set of RE in a minimally fatigued state, optimizing recovery between training sessions, and (potentially) periodizing the training stimulus over time. Equipped with these insights, we identify potential opportunities for further maximizing strength gains. Finally, we identify opportunities for increasing or maintaining strength when traditional heavy RE cannot be performed.

Volume Reduction: Which Dose is Sufficient to Retain Resistance Training Adaptations in Older Women?

We compared the effects of different resistance training (RT) volume reduction strategies on muscular strength and lean soft-tissue (LST) in older women. Fifty-seven physically independent women (>60 years) performed a 20-week pre-conditioning phase of a standardized whole-body RT program (eight exercises, three sets, 8-12 repetitions, three sessions a week), and were then randomly assigned to one of the following conditions: reduced volume for a single set (RV1, n=20) or two sets (RV2, n=19), or maintained volume of three sets (MV, n=18) for 8 weeks (specific training phase). Muscular strength in the chest press, leg extension, and preacher curl exercises was determined by one-repetition maximum tests. A dual-energy X-ray absorptiometry device was used to estimate LST. An increase in muscular strength (16.3-32.1%) and LST (3.2-7.9%) was observed after the pre-conditioning phase. There was an increase in chest press for all groups (9.4-16.7%) after the specific training phase. In contrast, only MV increased significantly in the leg extension (4.4%). No between-group differences were revealed for LST in the specific training phase. Our results suggest that reduced RT volume from three to one set per exercise for 8 weeks seems sufficient to retain neuromuscular adaptations in older women.

Does HMB Enhance Body Composition in Athletes? A Systematic Review and Meta-analysis.

ABSTRACT: Holland, BM, Roberts, BM, Krieger, JW, and Schoenfeld, BJ. Does HMB enhance body composition in athletes? A systematic review and meta-analysis. J Strength Cond Res 36(2): 585-592, 2022-The purpose of this article was to systematically review and meta-analyze the current literature to determine the effects of HMB on body composition in athletes. Studies were deemed eligible for inclusion if they met the following criteria: (a) were an experimental design published in a peer-reviewed, English-language journal; (b) included human athletic populations; (c) assessed body mass (BM), fat mass (FM), or fat-free mass (FFM) using a validated measure; (d) and had a minimum supplementation period of 4 weeks. Separate analyses were performed for BM, FM, and FFM using robust variance random-effects meta-regression for multilevel data structures, with adjustments for small samples. The final analysis of BM comprised a total of 208 subjects from 7 studies. Analysis of FFM and FM encompassed 5 studies comprising 161 subjects and 5 studies comprising 128 subjects, respectively. The principal finding of this analysis suggests HMB may have a small, positive impact on FFM in athletes (0.30 ± 0.13; 95% confidence interval [CI]: -0.07 to 0.68; p = 0.08), although this seems specific to when protein intake is suboptimal (<1.6 g·kg-1·d-1). Consistent with previous research on athletes, HMB demonstrated no significant effect on BM (-0.02 ± 0.04; 95% CI: -0.14 to 0.10; p = 0.70) and a small, nonsignificant effect on FM (-0.33 ± 0.23; 95% CI: -0.96 to 0.31; p = 0.22). More research is required to establish HMB's influence on FFM in athletes. It is also important to consider the dosage of HMB and training parameters of athletes because these will likely influence the efficacy of supplementation.

Effect of Equal Volume, High-Repetition Resistance Training to Volitional Fatigue, With Different Workout Frequencies, on Muscle Mass and Neuromuscular Performance in Postmenopausal Women.

ABSTRACT: Grzyb, K, Candow, DG, Schoenfeld, BJ, Bernat, P, Butchart, S, and Neary, JP. Effect of equal volume, high-repetition resistance training to volitional fatigue, with different workout frequencies, on muscle mass and neuromuscular performance in postmenopausal women. J Strength Cond Res 36(1): 31-36, 2022-This study examined the effects of equal volume, high-repetition resistance training (HRRT) performed to volitional fatigue, with different workout frequencies, on muscle mass and neuromuscular performance (strength, endurance) in untrained postmenopausal women. Subjects were randomized to perform HRRT 2 d·wk-1 (HRRT-2; 3 sets of 20-30 repetitions/set for elbow and knee flexion and extension) or 3 d·wk-1 (HRRT-3; 2 sets of 20-30 repetitions/set per exercise) for 8 weeks. Baseline and post-training assessments were made for muscle thickness, strength (1 repetition maximum [1RM]) and endurance (number of repetitions performed at 50% baseline 1RM) for elbow and knee flexor and extensor muscle groups. Significance was set at p < 0.05. There was a significant increase over time for all measures of muscle thickness, strength, and endurance (p < 0.005), with no differences between groups. Untrained postmenopausal women can expect to achieve similar improvements in muscle size, strength, and endurance when training 2 or 3 days per week, provided total weekly training volume is equal.

Effects of Different Resistance Training Loads on the Muscle Quality Index in Older Women.

ABSTRACT: Ribeiro, AS, Picoloto, A, Nunes, JP, Bezerra, ES, Schoenfeld, BJ, and Cyrino, ES. Effects of different resistance training loads on the muscle quality index in older women. J Strength Cond Res 36(5): 1445-1449, 2022-The purpose of this study was to investigate the effects of resistance training (RT) performed using low vs. moderate loads on muscular strength, muscle mass, and muscle quality index (MQI) in older women. Twenty-seven older women (71.5 ± 5 years, 65.2 ± 11 kg, 154.2 ± 5 cm, and 27.4 ± 4 kg·m-2) were randomized into 2 groups: one that performed RT with a low load (LOW, n = 13) and another that performed RT with a moderate load (MOD, n = 14). An 8-week RT program was performed 3 d·wk-1. Outcomes included 1-repetition maximum (1RM) tests and assessment of body composition by dual-energy X-ray absorptiometry. The LOW load consisted of a relative load at 15RM, whereas the MOD load consisted of a relative load at 10RM. Both groups presented significant changes from pre-training to post-training for chest press 1RM (LOW = 10.3%, and MOD = 11.1%), knee extension 1RM (LOW = 14.4%, and MOD = 16.6%), preacher curl 1RM (LOW = 12.4%, and MOD = 12.0%), fat-free mass (LOW = 2.1%, and MOD = 1.9%), body fat (LOW = -3.2%, and MOD = -2.7%), and MQI (LOW = 10.6%, and MOD = 11.3%). Results were similar (p > 0.05) between groups. These findings suggest that LOW and MOD loads are equally effective for promoting improvements in muscular strength and muscle growth as well as the MQI in older women.

Does Varying Resistance Exercises Promote Superior Muscle Hypertrophy and Strength Gains? A Systematic Review.

ABSTRACT: Kassiano, W, Nunes, JP, Costa, B, Ribeiro, AS, Schoenfeld, BJ, and Cyrino, ES. Does varying resistance exercises promote superior muscle hypertrophy and strength gains? A systematic review. J Strength Cond Res 36(6): 1753-1762, 2022-Fitness professionals routinely employ a variety of resistance training exercises in program design as a strategy to enhance muscular adaptations. However, it remains uncertain whether such an approach offers advantages over a fixed-exercise selection. The objective of this review was to review the effects of exercise variation on muscle hypertrophy and strength. A search of the literature was conducted using PubMed/MEDLINE, Scopus, and Web of Science databases. Eight studies were identified as meeting inclusion criteria. The combined total sample of the studies was N = 241, comprising all young men. The methodological quality of included studies was considered "good" and "excellent" based on the Physiotherapy Evidence Database Scale. The available studies indicate that varying exercise selection can influence muscle hypertrophy and strength gains. Some degree of systematic variation seems to enhance regional hypertrophic adaptations and maximize dynamic strength, whereas excessive, random variation may compromise muscular gains. We conclude that exercise variation should be approached systematically with a focus on applied anatomical and biomechanical constructs; on the contrary, employing different exercises that provide a redundant stimulus, as well as excessive rotation of different exercises (i.e., high frequency of change), may actually hinder muscular adaptations.

Does Varying Repetition Tempo in a Single-Joint Lower Body Exercise Augment Muscle Size and Strength in Resistance-Trained Men?

ABSTRACT: Pearson, J, Wadhi, T, Barakat, C, Aube, D, Schoenfeld, BJ, Andersen, JC, Barroso, R, Ugrinowitsch, C, and De Souza, EO. Does varying repetition tempo in a single-joint lower body exercise augment muscle size and strength in resistance-trained men? J Strength Cond Res 36(8): 2162-2168, 2022-This study compared the effects of FAST and SLOW eccentric repetition tempo in a single exercise volume-matched intervention on muscle thickness (MT) and strength in resistance-trained men. Using a within-subject design, 13 subjects had each leg randomly assigned to SLOW (1-0-3) or FAST (1-0-1) repetition tempo. Subjects underwent an 8-week strength-training (ST) intervention performed twice weekly. Unilateral leg-extension one repetition-maximum (1RM) and anterior thigh MT at the proximal (MTP) and distal (MTD) portions were assessed via ultrasound imaging at baseline and after 8 weeks of RT. Rating of perceived exertion (RPE) assessments of the training sessions (i.e., 16 per leg) were averaged for further analysis. Both legs similarly increased MTP (estimated differences: FAST: 0.24 cm, 3.6%; SLOW: 0.20 cm, 3.1%). However, for MTD, analysis of covariance analysis showed a leg effect ( p = 0.02) in which absolute pre-to-post change was greater in FAST compared with SLOW (estimated differences: FAST 0.23 cm, 5.5%; SLOW: 0.13 cm, 2.2%). For 1RM, both legs similarly increased maximum strength (estimated differences: FAST: 9.1 kg, 17.0%; SLOW: 10.4 kg, 22.1%, p ≤ 0.0001). The SLOW group had a higher RPE than FAST (8.59 vs. 7.98, p = 0.002). Despite differences in RPE, our results indicate that both repetition tempos produced similar muscular adaptations. However, they also suggest that the FAST tempo may provide a small hypertrophic advantage at the distal quadriceps. From a practical standpoint, strength and conditioning professionals may implement a FAST tempo at least in one single-joint exercise during an 8-week training period to enhance regional hypertrophic adaptations in trained individuals.

Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training.

ABSTRACT: Lasevicius, T, Schoenfeld, BJ, Silva-Batista, C, Barros, TdS, Aihara, AY, Brendon, H, Longo, AR, Tricoli, V, Peres, BdA, and Teixeira, EL. Muscle failure promotes greater muscle hypertrophy in low-load but not in high-load resistance training. J Strength Cond Res 36(2): 346-351, 2022-The purpose of this study was to investigate the effects of an 8-week resistance training program at low and high loads performed with and without achieving muscle failure on muscle strength and hypertrophy. Twenty-five untrained men participated in the 8-week study. Each lower limb was allocated to 1 of 4 unilateral knee extension protocols: repetitions to failure with low load (LL-RF; ∼34.4 repetitions); repetitions to failure with high load (HL-RF; ∼12.4 repetitions); repetitions not to failure with low load (LL-RNF; ∼19.6 repetitions); and repetitions not to failure with high load (HL-RNF; ∼6.7 repetitions). All conditions performed 3 sets with total training volume equated between conditions. The HL-RF and HL-RNF protocols used a load corresponding to 80% 1 repetition maximum (RM), while LL-RF and LL-RNF trained at 30% 1RM. Muscle strength (1RM) and quadriceps cross-sectional area (CSA) were assessed before and after intervention. Results showed that 1RM changes were significantly higher for HL-RF (33.8%, effect size [ES]: 1.24) and HL-RNF (33.4%, ES: 1.25) in the post-test when compared with the LL-RF and LL-RNF protocols (17.7%, ES: 0.82 and 15.8%, ES: 0.89, respectively). Quadriceps CSA increased significantly for HL-RF (8.1%, ES: 0.57), HL-RNF (7.7%, ES: 0.60), and LL-RF (7.8%, ES: 0.45), whereas no significant changes were observed in the LL-RNF (2.8%, ES: 0.15). We conclude that when training with low loads, training with a high level of effort seems to have greater importance than total training volume in the accretion of muscle mass, whereas for high load training, muscle failure does not promote any additional benefits. Consistent with previous research, muscle strength gains are superior when using heavier loads.

Improvement of Oxidative Stress in Older Women Is Dependent on Resistance Training Volume: Active Aging Longitudinal Study.

ABSTRACT: Cunha, PM, Ribeiro, AS, Padilha, C, Nunes, JP, Schoenfeld, BJ, Cyrino, LT, Tomeleri, CM, Nascimento, MA, Antunes, M, Fernandes, RR, Barbosa, DS, Venturini, D, Burini, RC, Sardinha, LB, and Cyrino, ES. Improvement of oxidative stress in older women is dependent on resistance training volume: Active aging longitudinal study. J Strength Cond Res 36(4): 1141-1146, 2022-The purpose of the present study was to investigate the effects of resistance training (RT) performed with a higher versus lower training volume on oxidative stress (OS) biomarkers in older women. Thirty-eight older women (≥60 years) were randomly assigned to 1 of 2 groups: a group that performed 1 set per exercise (low volume [LV], n = 18) or 3 sets per exercise (high volume [HV], n = 20). The whole-body RT consisted of a 12-week RT program involving 8 exercises performed with sets of 10-15 repetitions maximum, 3 days per week. Advanced oxidation protein products (AOPP), total radical-trapping antioxidant parameter (TRAP), and ferrous oxidation-xylenol orange (FOX) were used as OS biomarkers. The composite Z-score of the percentage changes from pre- to posttraining of OS biomarkers according to groups was calculated. A significant main effect of time (p < 0.05) was found for AOPP (LV = -7.3% vs. HV = -12.2%) and TRAP (LV = +1.5% vs. HV = +15.5%) concentrations, without a statistical difference between the groups (p > 0.05). A significant group vs. time interaction (p < 0.001) was revealed for FOX (LV = +6.4% vs. HV = -8.9%). The overall analysis indicated higher positive changes for HV than LV (composed Z-score: HV = 0.41 ± 1.22 vs. LV = -0.37 ± 1.03; p < 0.05). Our results suggest that a greater volume of RT seems to promote superior improvements on OS biomarkers in older women.

Reduced Dose of Beta-Alanine Is Sufficient to Maintain Performance in Repeated Sprints.

ABSTRACT: Zandona, BA, Ramos, RA, de Oliveira, CdS, McAnulty, SR, Ferreira, LHB, Smolarek, AC, Enes, AAN, Urbinati, KMdSS, Aragon, AA, Schoenfeld, BJ, and de Souza Junior, TP. Reduced Dose of Beta-Alanine Is Sufficient to Maintain Performance in Repeated Sprints. J Strength Cond Res 36(6): 1636-1642, 2022-Beta-alanine (BA) supplementation has been shown to be effective in improving physical performance by increasing carnosine concentration. However, it is still necessary to know the effect of a maintenance dose on performance. Thus, this study aimed to investigate the effects of a maintenance dose of BA supplementation on performance. Forty-four anaerobically trained men with 23.9 ± 3.8 years of age, 176.0 ± 0.05 cm height, 81.2 ± 7.5 kg body mass, and 15.5 ± 2.9% of body fat performed a cycle ergometer test consisting of 4 sprints of 30 s with 4 minutes of active recovery. The study comprised 3 phases: (a) presupplementation, (b) supplementation with 6.4 g·d-1 BA or placebo, and (c) postsupplementation with a maintenance dose of 1.2 g·d-1 of BA or interruption of supplementation. Data were analyzed using generalized estimated equations with a priori 0.05 level of significance. The placebo group and interruption group presented a lower power (7.28 ± 0.66 and 7.71 ± 0.42 W·kg-1 vs. 8.04 ± 0.84 and 9.25 ± 1.18 W·kg-1, respectively; p < 0.05) during the third sprint in postsupplementation, whereas the maintenance group maintained the required power (7.47 ± 1.03 vs. 8.74 ± 1.07 W·kg-1; p > 0.05). The placebo group also presented higher percentage of fatigue (44.5% ± 12.3 and 44.8% ± 7.7 vs. 37.6 ± 7.2%; p = 0.021) and higher subjective perception of exertion (8.92 ± 0.90 vs. 8.00 ± 1.60; p = 0.028). Therefore, the maintenance dose of 1.2 g·d-1 BA was effective in maintaining performance, whereas a reduction in performance was observed after supplementation interruption.