Increasing set volume relative to baseline does not augment skeletal muscle adaptations when compared to maintenance of baseline training volume in recreationally trained individuals

PURPOSE

This study compared the effects of prescribing an increased number of sets relative to baseline (ITV) to a maintenance of baseline training volume (BTV), in previously trained individuals.

METHODS

Forty-two adults with more than 6 months of elbow flexion resistance training experience had each arm randomized to either the ITV or BTV condition. Participants performed 2-weekly sessions of unilateral standing dumbbell elbow flexion exercise for 12 weeks, 8 of which were supervised. Muscle thickness of the elbow flexors at 50, 60, and 70% the distance of the upper arm and one repetition-maximum (1RM) strength for the unilateral standing dumbbell elbow flexion exercise were assessed pre- and post-intervention.

RESULTS

For the 50% site, there was no evidence that the changes were different between BTV and ITV [∆BTV vs ∆ITV (cm) = 0.022 (95% CI - 0.096, 0.140)]. However, there was evidence that both conditions observed a greater change compared to the control. For the 60% site, there was no evidence that the changes were different between BTV and ITV [∆BTV vs ∆ITV (cm) = - 0.010 (95% CI - 0.155, 0.96)]. However, there was evidence that both conditions observed a greater change compared to the control. For the 70% site, there was no evidence that the changes were different between BTV and ITV [∆BTV vs ∆ITV (cm) = 0.004 (95% CI - 0.092, 0.101)]. However, there was evidence that both conditions observed a greater change compared to the control. For changes in 1RM, there was evidence that the change was greater in the BTV [∆BTV vs ∆Control (kg) = 1.915 (95% CI 1.219, 2.611)] and ITV [∆ITV vs ∆Control (kg) = 1.780 (95% CI 1.084, 2.475)] conditions compared to control.

CONCLUSION

Prescribing an increased dose of sets relative to baseline did not augment muscular adaptations when compared to a maintenance of BTV, in recreationally trained individuals. Both training conditions were similarly effective in promoting significant increases in muscle thickness and 1RM strength of the elbow flexors.

Higher volume resistance training enhances whole-body muscle hypertrophy in postmenopausal and older females: A secondary analysis of systematic review and meta-analysis of randomized clinical trials

OBJECTIVE

This study explored the effects of resistance training (RT) volume on muscle hypertrophy in postmenopausal and older females.

METHODS

This systematic review searched randomized controlled trials (RCTs) on PubMed/MEDLINE, Scopus, Web of Science, and SciELO. Studies with postmenopausal (age ≥ 45 y) or older females (age ≥ 60 y) that compared RT (whole-body) effects on muscle hypertrophy with a control group (CG) were included. Independently reviewers selected the studies, extracted data, and performed the risk of bias of RCTs (RoB2) and certainty of the evidence (GRADE). Whole-body lean mass, free-fat mass, and skeletal muscle mass measurements were included as muscle hypertrophy outcomes. A random-effects model standardized mean difference (Hedges'g), and 95% confidence interval (95%CI) were used for meta-analysis.

RESULTS

Fourteen RCTs (overall RoB2: some concerns, except one study with high risk; GRADE: low evidence) were included. RT groups were divided into low (LVRT, total volume: 445.0 au) and high-volume (HVRT, total volume: 997.3 au). Most exercises performed were arm curl, bench press or chest press, calf raise, leg curl, leg extension, leg press or squat, seated row or lat pulldown, and triceps pushdown. Both groups experienced muscle hypertrophy (HVRT = ∼1.3 kg vs. LVRT = ∼0.9 kg) when compared to CG, although HVRT demonstrated moderate effects size (HVRT = 0.52, 95%CI: 0.27, 0.77) and LVRT demonstrated small effects size (LVRT = 0.34, 95%CI: 0.14, 0.53).

CONCLUSIONS

Compared to CG, results suggest that the HVRT protocol elicits superior improvements in muscle hypertrophy outcomes than LVRT in postmenopausal and older females.

The Importance of Recovery in Resistance Training Microcycle Construction

Systemic resistance training aims to enhance performance by balancing stress, fatigue and recovery. While fatigue is expected, insufficient recovery may temporarily impair performance. The aim of this review was to examine evidence regarding manipulation of resistance training variables on subsequent effects on recovery and performance. PubMed, Medline, SPORTDiscus, Scopus and CINAHL were searched. Only studies that investigated recovery between resistance training sessions were selected, with a total of 24 articles included for review. Training to failure may lengthen recovery times, potentially impairing performance; however, it may be suitable if implemented strategically ensuring adequate recovery between sessions of similar exercises or muscle groups. Higher volumes may increase recovery demands, especially when paired with training to failure, however, with wide variation in individual responses, it is suggested to start with lower volume, monitor recovery, and gradually increase training volume if appropriate. Exercises emphasising the lower body, multi-joint movements, greater muscle recruitment, eccentric contractions, and/or the lengthened position may require longer recovery times. Adjusting volume and frequency of these exercises can affect recovery demands depending on the goals and training logistics. Daily undulating programming may maximise performance on priority sessions while maintaining purposeful and productive easy days. For example, active recovery in the form of training opposing muscle groups, light aerobic cardio, or low-volume power-type training may improve recovery and potentially elicit a post activation potentiation priming effect compared to passive recovery. However, it is possible that training cessation may be adequate for allowing sufficient recovery prior to sessions of importance.

Effects of Different Weekly Set Progressions on Muscular Adaptations in Trained Males: Is There a Dose-Response Effect?

PURPOSE

This study investigated the effect of progressively adding sets for the lower limb every 2 wk versus performing a constant set volume in resistance-trained males.

METHODS

Thirty-one resistance-trained males (age = 24.4 ± 2.9 yr, height = 175.5 ± 6.5 cm, body mass = 80.1 ± 9.4 kg, body fat = 14.4% ± 3.1%, resistance training [RT] experience = 5.1 ± 2.2 yr; one-repetition maximum [1RM] barbell back squat: body mass ratio = 1.7 ± 0.1 a.u.) were randomly allocated into a constant group (CG, n = 10), a four-set progression group (4SG, n = 10) or a six-set progression group (6SG, n = 11). After a 2-wk washout period and another 2-wk familiarization period, participants performed a lower-limb training program twice a week for 12 wk. Maximum dynamic strength (1RM) in the barbell back squat, vastus lateralis cross-sectional area, and the sum of lateral thigh muscle thickness at 30%, 50%, and 70% of the femur length were assessed at baseline and after the 12-wk training program.

RESULTS

Regarding 1RM, multiple comparisons revealed that 6SG elicited higher muscle strength gains than 4SG ( P = 0.002) and CG ( P < 0.0001), and 4SG had greater improvements than CG ( P = 0.023). Cross-sectional area and sum of lateral thigh muscle thickness showed no between-group differences ( P = 0.067 and P = 0.076, respectively). However, an inspection of 95% confidence intervals suggests a potential dose-response relationship, with results appearing to plateau in the higher volume conditions.

CONCLUSIONS

Our results suggest that progressively adding four or six sets per week every 2 wk elicited greater lower-limb strength in resistance-trained individuals over a 12-wk training period. Although our findings indicate a possible small benefit for higher volume conditions regarding hypertrophic adaptations in this population, the limited certainty of our findings warrants caution.

Minimalist Training: Is Lower Dosage or Intensity Resistance Training Effective to Improve Physical Fitness? A Narrative Review

BACKGROUND

Findings from original research, systematic reviews, and meta-analyses have demonstrated the effectiveness of resistance training (RT) on markers of performance and health. However, the literature is inconsistent with regards to the dosage effects (frequency, intensity, time, type) of RT to maximize training-induced improvements. This is most likely due to moderating factors such as age, sex, and training status. Moreover, individuals with limited time to exercise or who lack motivation to perform RT are interested in the least amount of RT to improve physical fitness.

OBJECTIVES

The objective of this review was to investigate and identify lower than typically recommended RT dosages (i.e., shorter durations, lower volumes, and intensity activities) that can improve fitness components such as muscle strength and endurance for sedentary individuals or beginners not meeting the minimal recommendation of exercise.

METHODS

Due to the broad research question involving different RT types, cohorts, and outcome measures (i.e., high heterogeneity), a narrative review was selected instead of a systematic meta-analysis approach.

RESULTS

It seems that one weekly RT session is sufficient to induce strength gains in RT beginners with < 3 sets and loads below 50% of one-repetition maximum (1RM). With regards to the number of repetitions, the literature is controversial and some authors report that repetition to failure is key to achieve optimal adaptations, while other authors report similar adaptations with fewer repetitions. Additionally, higher intensity or heavier loads tend to provide superior results. With regards to the RT type, multi-joint exercises induce similar or even larger effects than single-joint exercises.

CONCLUSION

The least amount of RT that can be performed to improve physical fitness for beginners for at least the first 12 weeks is one weekly session at intensities below 50% 1RM, with < 3 sets per multi-joint exercise.

Effects of Acute Loading Induced Fatigability, Acute Serum Hormone Responses and Training Volume to Individual Hypertrophy and Maximal Strength during 10 Weeks of Strength Training

This study investigated whether a strength training session-induced acute fatigue is related to individuals' strength training adaptations in maximal force and/or muscle hypertrophy, and whether acute responses in serum testosterone (T) and growth hormone (GH) concentrations during the training sessions would be associated with individual neuromuscular adaptations. 26 males completed the 10-week strength-training intervention, which included fatiguing dynamic leg press acute loading bouts (5 x 10 RM) at weeks two, four, six, and ten. Blood samples were collected before and after the loading and after 24h of recovery for serum T, GH, and cortisol (C) concentrations at weeks 2, 6, and 10. The cross-sectional area of the vastus lateralis was measured by ultrasonography. Isometric force measurements were performed before and immediately after loadings, and loading-induced acute decrease in maximal force was reported as the fatigue percentage. The subjects were split into three groups according to the degree of training-induced muscle hypertrophy after the training period. Increases in isometric force were significant for High Responders (HR, n = 10) (by 24.3 % ± 17.2, p = 0.035) and Medium Responders (MR, n = 7) (by 23.8 % ± 5.5, p = 0.002), whereas the increase of 26.2 % (±16.5) in Low Responders (LR, n = 7) was not significant. The amount of work (cm + s) increased significantly at every measurement point in all the groups. A significant correlation was observed between the fatigue percentage and relative changes in isometric force after the training period for the whole group (R = 0.475, p = 0.022) and separately only in HR (R = 0.643, p = 0.049). Only the HR group showed increased acute serum GH concentrations at every measurement point. There was also a significant acute increase in serum T for HR at weeks 6 and 10. HR showed the strongest correlation between acute loading-induced fatigue and isometric force gains. HR was also more sensitive to acute increases in serum concentrations of T and GH after the loading. Acute fatigue and serum GH concentrations may be indicators of responsiveness to muscle strength gain and, to some extent, muscle hypertrophy.

Characteristics of resistance training-based protocols in older adults with sarcopenic obesity: a scoping review of training procedure recommendations

Background

Sarcopenic obesity (SO) is a clinical and functional disease characterized by the coexistence of obesity and sarcopenia. Resistance training (RT) characteristics for older adults with sarcopenia or obesity are already well established in the scientific literature. Nonetheless, we still do not know how detailed the RT protocols are described for older adults with SO. Therefore, we aimed to analyze the characteristics of RT programs, including each of their variables, recommended for older adults with SO.

Methods

This is a scoping review study that was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Scoping Reviews. The search was carried out until November 2022 in PubMed/MEDLINE, EMBASE, Cochrane Library, Web of Science, Scopus, LILACS, Google Scholar, and medRxiv databases. The studies included SO diagnosis and RT as an intervention strategy. The RT variables analyzed were as follows: exercise selection, the volume of sets, the intensity of load, repetition cadence, rest interval between sets, and weekly frequency.

Results

A total of 1,693 studies were identified. After applying the exclusion criteria, 15 studies were included in the final analysis. The duration of the RT intervention ranged from 8 to 24 weeks. All studies included full-body routines, with single/multi-joint exercises. Regarding the volume of sets, some studies fixed it in three sets, whereas others varied between one and three sets. The load was reported by repetition range and the weight lifted, elastic-band color/resistance, percentage of one repetition maximum, or perceived exertion scale. Repetition cadence was fixed in some studies, while it was self-selected between concentric and eccentric phases in others. The interval between sets of rest varied from 30 to 180 s. All studies reported progression overload during the interventions. Not all studies reported how the exercise selection, repetition cadence, and rest interval were made.

Conclusion

The characteristics of RT protocols and their variables prescribed in the literature for older adults with SO were mapped. The lack of detail on some training variables (i.e., exercise selection, repetition cadence, and rest interval) was identified. RT protocols are heterogeneous and described only partially among studies. The recommendations for RT prescription details in older adults with SO are provided for future studies.

Systematic review registration

https://osf.io/wzk3d/.

Similar Responses in the Akt/Protein Kinase B Signaling Pathway Following Different Lower-Body Exercise Volumes in Recreationally Active Men

ABSTRACT

Pearson, JR, Moodie, N, Stout, KW, Hawkins, WC, Matuszek, M, Graham, ZA, Siedlik, JA, Vardiman, JP, and Gallagher, PM. Similar responses in the Akt/protein kinase B (PKB) signaling pathway after different lower-body exercise volumes in recreationally active men. J Strength Cond Res XX(X): 000-000, 2022-This project examined the differences between a single set (SS) compared to multiple sets (MS) of resistance exercise on the Akt/protein kinase B (PKB) signaling pathway, the expression of insulin-like growth factor-1 (IGF-1), and the receptor for IGF-1 (IGF-1R) to better understand the types of resistance training protocols that are most beneficial in stimulating the muscle hypertrophic response. Sixteen healthy men were randomly selected into 2 groups of 8. Subjects in each group received 3 biopsies: (a) before exercise, (b) 15 minutes postexercise, and (c) 180 minutes postexercise. Subjects in the SS group performed 1 set of leg press to failure at 80% of their predetermined 1 repetition maximum (1RM). Subjects in the MS group performed 2 sets of 10 repetitions and 1 set to failure at 80% of their predetermined 1RM, with 3 minutes of rest between each set. Our results indicated no group × time interactions in the concentration of Akt signaling proteins. Furthermore, there were no group × time interactions in IGF-1 or IGF-1R expression. However, phosphorylated 4E-binding protein 1 levels increased 150% from pre to 180 minutes post (p = 0.005). In addition, there was a significantly greater increase in IGF-1R expression in the SS group compared with the MS group (7.99 ± 10.07 vs. 4.41 ± 6.28; p = 0.026). Collectively, we found that a SS of resistance training evokes a similar acute Akt/PKB pathway response as MS in recreationally active men.

Resistance Training for Patients with Cancer: A Conceptual Framework for Maximizing Strength, Power, Functional Mobility, and Body Composition to Optimize Health and Outcomes

There are many benefits to the addition of exercise to cancer treatment and survivorship, particularly with resistance training regimens that target hypertrophy, bone mineral density, strength, functional mobility, and body composition. These goals are best achieved through a series of individualized high-intensity compound movements that mirror functional mobility patterns and sufficiently stress the musculoskeletal system. As a result of adequate stress, the body will engage compensatory cellular mechanisms that improve the structural integrity of bones and muscles, stimulate metabolism and the immune system, optimize functional performance, and minimize mechanical injury risk. The current evidence suggests that application of the above exercise principles, practiced in a safe environment under expert observation, may offer patients with cancer an effective means of improving overall health and cancer-specific outcomes. The following article poses several important questions certified exercise specialists and physicians should consider when prescribing resistance exercise for patients with cancer.

Effect of Resistance Exercise Orders on Health Parameters in Trained Older Women: A Randomized Crossover Trial

PURPOSE

This study aimed to compare the effects of four resistance exercise orders on muscular strength, body composition, functional fitness, cardiovascular risk factors, and mental health parameters in trained older women.

METHODS

The intervention lasted 63 wk. Sixty-one physically independent women (>60 yr) after completing a 12-wk resistance training (RT) preconditioning phase were randomized into four different exercise orders groups to perform 12 wk of RT: multijoint to single-joint and upper- to lower-body, single-joint to multijoint and upper- to lower-body, multijoint to single-joint and lower- to upper-body, and single-joint to multijoint and lower- to upper-body. This was followed by a 12-wk detraining period and another 12-wk RT in which exercise orders were crossed over between MJ-SJ and SJ-MJ conditions. Body composition (dual-energy x-ray absorptiometry), muscular strength (one-repetition maximum tests), functional fitness (gait speed, walking agility, 30-s chair stand, and 6-min walk tests), cardiovascular risk factors (glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, C-reactive protein, advanced oxidation protein product, total radical-trapping antioxidant parameter, and nitric oxide), depressive (Geriatric Depression Scale) and anxiety symptoms (Beck Anxiety Inventory), and cognitive performance (Montreal Cognitive Assessment, Trail Making, verbal fluency, and Stroop test) were analyzed.

RESULTS

After the final training period, all groups presented significant improvements ( P < 0.05) in almost all analyzed variables (muscular strength, body composition, functional tests, blood biomarkers, and mental health parameters), without significant difference among exercise orders.

CONCLUSIONS

Our results suggest that RT exercise orders in which MJ, SJ, upper, or lower-body exercises are performed first have similar effects on health parameters in trained older women.

Influence of Alpha-Actinin-3 R577X Polymorphism on Muscle Damage and the Inflammatory Response after an Acute Strength Training Session

The objective of this study was to verify the influence of the ACTN3 R577X polymorphism on muscle damage and the inflammatory response after an acute strength training (ST) session. Twenty-seven healthy male individuals (age: 25 ± 4.3 years) participated in the study, including 18 RR/RX and 9 XX individuals. The participants were divided into two groups (RR/RX and XX groups) and subjected to an acute ST session, which consisted of a series of leg press, leg extension machine, and seated leg curl machine. The volunteers were instructed to perform the greatest volume of work until concentric muscle failure. Each volunteer's performance was analyzed as the load and total volume of training, and the blood concentrations of C-C motif chemokine ligand 2 (CCL2), interleukin-8 (IL-8), creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin, testosterone, and cortisol were measured before the ST session and 30 min and 24 h postsession. The ACTN3 R577X polymorphism effect was observed, with increased concentrations of CCL2 (p < 0.01), IL-8 (p < 0.01), and LDH (p < 0.001) in XX individuals. There was an increase in the concentration of CK in the RR/RX group compared to XX at 24 h after training (p > 0.01). The testosterone/cortisol ratio increased more markedly in the XX group (p < 0.001). Regarding performance, the RR/RX group presented higher load and total volume values in the training exercises when compared to the XX group (p < 0.05). However, the XX group presented higher values of delayed onset muscle soreness (DOMS) than the RR/RX group (p < 0.05). The influence of ACTN3 R577X polymorphism on muscle damage and the inflammatory response was observed after an acute ST session, indicating that the RR/RX genotype shows more muscle damage and a catabolic profile due to a better performance in this activity, while the XX genotype shows more DOMS.

Effect of different training frequencies on maximal strength performance and muscle hypertrophy in trained individuals-a within-subject design

Several studies comparing resistance training (RT) frequencies may have been affected by the large between-subject variability. This study aimed to compare the changes in lower limbs maximal dynamic strength (1RM) and quadriceps femoris cross-sectional area (CSA) after a RT with different weekly frequencies in strength-trained individuals using a within-subject design. Twenty-four men participated in a 9-week RT program, being randomly divided into two conditions: resistance training with equalized total training volume (RTEV) and with unequalized total training volume (RTUV). The RT protocol used the unilateral leg press 45° exercise and each subject’s lower limb executed one of the proposed frequencies (one and three times/week). All conditions effectively increased 1RM and CSA (p<0.001); however, no significant differences were observed in the values of 1RM (p = 0.454) and CSA (p = 0.310) between the RT frequencies in the RTEV and RTUV conditions. Therefore, RT performed three times a week showed similar increases in 1RM and CSA to the program performed once a week, regardless of training volume equalization. Nevertheless, when the higher RT frequency allowed the application of a greater TTV (i.e., RTUV), higher effect size (ES) values (0.51 and 0.63, 1RM and CSA, respectively) were observed for the adaptations.

The Effects of Foam Rolling Training on Performance Parameters: A Systematic Review and Meta-Analysis including Controlled and Randomized Controlled Trials

Foam rolling (FR) is a new and popular technique for increasing range of motion. While there are a few studies that demonstrate increased performance measures after an acute bout of FR, the overall evidence indicates trivial performance benefits. As there have been no meta-analyses on the effects of chronic FR on performance, the objective of this systematic meta-analytical review was to quantify the effects of FR training on performance. We searched PubMed, Scopus, the Cochrane library, and Web of Science for FR training studies with a duration greater than two weeks, and found eight relevant studies. We used a random effect meta-analysis that employed a mixed-effect model to identify subgroup analyses. GRADE analysis was used to gauge the quality of the evidence obtained from this meta-analysis. Egger's regression intercept test (intercept 1.79; p = 0.62) and an average PEDro score of 6.25 (±0.89) indicated no or low risk of reporting bias, respectively. GRADE analysis indicated that we can be moderately confident in the effect estimates. The meta-analysis found no significant difference between FR and control conditions (ES = -0.294; p = 0.281; I² = 73.68). Analyses of the moderating variables showed no significant differences between randomized control vs. controlled trials (Q = 0.183; p = 0.67) and no relationship between ages (R² = 0.10; p = 0.37), weeks of intervention (R² = 0.17; p = 0.35), and total load of FR (R² = 0.24; p = 0.11). In conclusion, there were no significant performance changes with FR training and no specific circumstances leading to performance changes following FR training exceeding two weeks.

Resistance Training Variables for Optimization of Muscle Hypertrophy: An Umbrella Review

This umbrella review aimed to analyze the different variables of resistance training and their effect on hypertrophy, and to provide practical recommendations for the prescription of resistance training programs to maximize hypertrophy responses. A systematic research was conducted through of PubMed/MEDLINE, SPORTDiscus and Web of Science following the preferred reporting items for systematic reviews and meta-analyses statement guidelines. A total of 52 meta-analyses were found, of which 14 met the inclusion criteria. These studies were published between 2009 and 2020 and comprised 178 primary studies corresponding to 4,784 participants. Following a methodological quality analysis, nine meta-analyses were categorized as high quality, presenting values of 81–88%. The remaining meta-analyses were rated as moderate quality, with values between 63–75%. Based on this umbrella review, we can state that at least 10 sets per week per muscle group is optimal, that eccentric contractions seem important, very slow repetitions (≥10 s) should be avoided, and that blood flow restriction might be beneficial for some individuals. In addition, other variables as, exercise order, time of the day and type of periodization appear not to directly influence the magnitude of muscle mass gains. These findings provide valuable information for the design and configuration of the resistance training program with the aim of optimizing muscle hypertrophy.

Protocols aiming to increase muscle mass in persons with motor complete spinal cord injury: a systematic review

PURPOSE

The purpose of this review was to compare all intervention modalities aimed at increasing skeletal muscle mass (SMM) in the paralysed limbs of persons with chronic (>1-year post-injury), motor complete spinal cord injury (SCI).

MATERIALS AND METHODS

A systematic review of EMBASE, MEDLINE, Scopus, and SPORTDiscus databases was conducted from inception until December 2021. Published intervention studies aimed to increase SMM (measured by magnetic resonance imaging, computed tomography, ultrasound, muscle biopsy, or lean soft tissue mass by dual X-ray absorptiometry) in the paralysed limbs of adults (>18 years) with SCI were included.

RESULTS

Fifty articles were included that, overall, demonstrated a high risk of bias. Studies were categorised into six groups: neuromuscular electrical stimulation (NMES) with and without external resistance, functional electrical stimulation cycling, walking- and standing-based interventions, pharmacological treatments, and studies that compared or combined intervention modalities. Resistance training (RT) using NMES on the quadriceps produced the largest and most consistent increases in SMM of all intervention modalities.

CONCLUSIONS

Current evidence suggests that clinical practise aiming to increase SMM in the paralysed limbs of persons with motor complete SCI should perform NMES-RT. However, more high-quality randomised control trials are needed to determine how training variables, such as exercise volume and intensity, can be optimised for increasing SMM. Implications for rehabilitationPersons with spinal cord injury (SCI) experience severe reductions in skeletal muscle mass (SMM) post-injury, which may exacerbate their risk of obesity and metabolic disease.Out of all exercise and non-exercise-based interventions, this systematic review shows that neuromuscular electrical stimulation-based resistance training demonstrates the most robust and consistent evidence for increasing skeletal muscle mass in the paralysed limbs of adults with motor complete spinal cord injury.The findings from this review can be used to inform evidence-based practise for exercise practitioners, as well as direct future research focused on increasing muscle mass in this population.

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.

A 12-Week Randomized Double-Blind Placebo-Controlled Clinical Trial, Evaluating the Effect of Supplementation with a Spinach Extract on Skeletal Muscle Fitness in Adults Older Than 50 Years of Age

The aim of a 12-week randomized double-blind placebo-controlled study was to assess the effect of daily supplementation with a natural extract of Spinacia oleracea L. (4 × 500 mg capsules/day; total 2 g per day) combined with a moderate-intensity training program (1 h session/3 times a week) on skeletal muscle fitness in adults over 50 years of age. Muscle strength assessed by isokinetic and isometric dynamometry improved significantly in the experimental (n = 23) and the placebo (n = 22) groups, but the magnitude of improvement was higher in the experimental group, with between-group differences in almost all variables, including isokinetic at 60° s⁻¹ in knee extension, peak torque (p < 0.007); total work per repetition maximum (p < 0.009); isokinetic at 180°s⁻¹ in knee extension, peak torque (p < 0.002); total work (p < 0.007); total work per repetition maximum (p < 0.005); average power (p < 0.027); isometric in knee extension, peak torque (p < 0.005); and average peak torque (p < 0.002). Similar findings were observed for muscle quality. Changes in quality of life (SF-36) were not found, except for improvements in the role physical (p < 0.023) and role emotional (p < 0.001) domains, likely as a result of the physical training sessions. A nutritional survey did not revealed changes in dietary habits. No adverse events were recorded. In subjects over 50 years of age, moderate-intensity strength training combined with daily supplementation for 12 weeks with a natural extract of Spinacia oleracea L. improved muscle-related variables and muscle quality. Maintaining muscle health is a key component of healthy aging.

Effect of 10 sets versus 5 sets of resistance training on muscular endurance

BACKGROUND

A paucity of research exists examining whether resistance training with a greater number of sets per exercise enhances the development of muscular endurance. The aim of this study was to investigate the effects of ten sets versus five sets of resistance training on muscle endurance.

METHODS

Fifteen healthy males (age 23.7 ± 4.6 y) with at least 1 year resistance training experience were randomly assigned to 6 weeks of 10 sets (10-SET) or 5 sets (5-SET) of 10 repetitions at 60-80% one-repetition maximum (1RM) for specific compound resistance exercises with rest intervals between sets of 60-90 s and 60 s between exercises, performed 3 times per week. Relative muscle endurance test was assessed via maximal repetitions using 70% 1RM for the bench press, lat pulldown and leg press.

RESULTS

There was a significant increase in the number of repetitions to failure in the muscle endurance test for the leg press in 10-SET (40.9%, p = 0.04) and 5-SET (27.9%; p = 0.03), although no statistical differences between groups in the post-intervention results. Both groups increased volume-load in the muscle endurance test for the bench press (≥14.3%, p<0.05) and leg press (≥36.7%, p<0.05), but there were no statistical differences between groups in the post-intervention results.

CONCLUSIONS

Findings suggest that performing 10 sets compared to 5 sets of resistance training does not enhance the development of relative muscle endurance. The volume-load accrued within an individual set rather than across sets may be of greater importance when targeting muscular endurance.

Quantity of Resistance Exercise for Breast Cancer Patients: Does the Dose Match the Objective?

ABSTRACT

Rosenberg, J, Hyde, PN, Yancy, WS, Ford, KM, and Champ, CE. Quantity of resistance exercise for breast cancer patients: does the dose match the objective? J Strength Cond Res 35(5): 1467-1476, 2021-There is currently a lack of consensus as to what defines exercise and resistance training in the cancer setting and whether current studies comply with exercise guidelines. This study aimed to quantify the available research studies using resistance training exercise interventions in the breast cancer setting for future clinical trial utilization. We systemically reviewed all available resistance exercise studies during and after breast cancer treatment in an attempt to quantify to the prescribed dose and whether regimens aligned with general exercise guidelines to improve functional mobility, body composition, and metabolic function. They were then compared with recommendations set forth by the national committees that create evidence-based exercise guidelines. Fifty studies met the initial criteria, with 35 meeting analysis criteria for evaluation. Fifteen studies evaluated an exercise regimen during cancer treatment, and 20 evaluated a regimen after treatment. The average adherence rates were 84% for all studies. Only 23 studies listed specific exercises used within the protocol. Most exercise regimens relied on open chain movements and machine exercises. Around half of studies met criteria to achieve hypertrophy, and 66% met American College of Sports Medicine exercise guidelines for cancer patients. A minority of breast cancer studies implementing a resistance training exercise regimen prescribed a regimen or specific dose that follows general exercise guidelines. This study highlights a potential deficiency in exercise programs designed for patients with breast cancer, and these findings should be considered in future study design.

Equating Resistance-Training Volume Between Programs Focused on Muscle Hypertrophy

Calculating resistance-training volume in programs focused on muscle hypertrophy is an attempt to quantify the external workload carried out, then to estimate the dose of stimulus imposed on targeted muscles. The volume is usually expressed in some variables that directly affected the total training work, such as the number of sets, repetitions, and volume-load. These variables are used to try to quantify the training work easily, for the subsequent organization and prescription of training programs. One of the main uses of measures of volume quantification is seen in studies in which the purpose is to compare the effects of different training protocols on muscle growth in a volume-equated format. However, it seems that not all measures of volume are always appropriate for equating training protocols. In the current paper, it is discussed what training volume is and the potentials and shortcomings of each one of the most common ways to equate it between groups depending on the independent variable to be compared (e.g., weekly frequency, intensity of load, and advanced techniques).

Resistance training with different repetition duration to failure: effect on hypertrophy, strength and muscle activation

Background

This study investigated the effects of two 14-week resistance training protocols with different repetition duration (RD) performed to muscle failure (MF) on gains in strength and muscle hypertrophy as well as on normalized electromyographic (EMG) amplitude and force-angle relationships.

Methods

The left and right legs of ten untrained males were assigned to either one of the two protocols (2-s or 6-s RD) incorporating unilateral knee extension exercise. Both protocols were performed with 3–4 sets, 50–60% of the one-repetition maximum (1RM), and 3 min rest. Rectus femoris and vastus lateralis cross-sectional areas (CSA), maximal voluntary isometric contraction (MVIC) at 30^o and 90^o of knee flexion and 1RM performance were assessed before and after the training period. In addition, normalized EMG amplitude-angle and force-angle relationships were assessed in the 6^th and 39^th experimental sessions.

Results

The 6-s RD protocol induced larger gains in MVIC at 30^o of knee angle measurement than the 2-s RD protocol. Increases in MVIC at 90^o of knee angle, 1RM, rectus femoris and vastus lateralis CSA were not significant between the 2-s and 6-s RD protocols. Moreover, different normalized EMG amplitude-angle and force-angle values were detected between protocols over most of the angles analyzed.

Conclusion

Performing longer RD could be a more appropriate strategy to provide greater gains in isometric maximal muscle strength at shortened knee positions. However, similar maximum dynamic strength and muscle hypertrophy gains would be provided by protocols with different RD.

Are We Exploring the Potential Role of Specialized Techniques in Muscle Hypertrophy?

Specialized resistance training techniques (e.g., drop-set, rest-pause) are commonly used by well-trained subjects for maximizing muscle hypertrophy. Most of these techniques were designed to allow a greater training volume (i.e., total repetitions×load), due to the supposition that it elicits greater muscle mass gains. However, many studies that compared the traditional resistance training configuration with specialized techniques seek to equalize the volume between groups, making it difficult to determine the inherent hypertrophic potential of these advanced strategies, as well as, this equalization restricts part of the practical extrapolation on these findings. In this scenario, the objectives of this manuscript were 1) to present the nuance of the evidence that deals with the effectiveness of these specialized resistance training techniques and - primarily - to 2) propose possible ways to explore the hypertrophic potential of such strategies with greater ecological validity without losing the methodological rigor of controlling possible intervening variables; and thus, contributing to increasing the applicability of the findings and improving the effectiveness of hypertrophy-oriented resistance training programs.

Emphasizing Task-Specific Hypertrophy to Enhance Sequential Strength and Power Performance

While strength is indeed a skill, most discussions have primarily considered structural adaptations rather than ultrastructural augmentation to improve performance. Altering the structural component of the muscle is often the aim of hypertrophic training, yet not all hypertrophy is equal; such alterations are dependent upon how the muscle adapts to the training stimuli and overall training stress. When comparing bodybuilders to strength and power athletes such as powerlifters, weightlifters, and throwers, while muscle size may be similar, the ability to produce force and power is often inequivalent. Thus, performance differences go beyond structural changes and may be due to the muscle's ultrastructural constituents and training induced adaptations. Relative to potentiating strength and power performances, eliciting specific ultrastructural changes should be a variable of interest during hypertrophic training phases. By focusing on task-specific hypertrophy, it may be possible to achieve an optimal amount of hypertrophy while deemphasizing metabolic and aerobic components that are often associated with high-volume training. Therefore, the purpose of this article is to briefly address different types of hypertrophy and provide directions for practitioners who are aiming to achieve optimal rather than maximal hypertrophy, as it relates to altering ultrastructural muscular components, to potentiate strength and power performance.

Effects of resistance training with controlled versus self-selected repetition duration on muscle mass and strength in untrained men

The aim of this study was to compare the effect of self-selected repetition duration (SELF), with and without volume load (VL) equalized with controlled repetition duration (CON) on muscle strength and hypertrophy in untrained males. We used a within-subjects design in which 20 volunteers (age: 24.7 ± 2.9 years) had one leg randomly assigned to CON (i.e., 2 s concentric, 2 s eccentric) and the other to SELF or to self-selected repetition duration with equalized volume load (SELF-EV). One repetition maximum (1-RM) and muscle cross-sectional area (CSA) were measured at baseline (Pre) and after (Post) resistance training (RT; 2×/wk for 8 weeks). For the main study variables (1-RM and muscle CSA), a mixed-model analysis was performed, assuming repetition duration (SELF, SELF-EV and CON), and time (Pre and Post) as fixed factors and the subjects as random factor for each dependent variable (1-RM and CSA). All RT protocols showed significant increases in values of 1-RM from Pre (CON: 73.7 ± 17.6 kg; SELF: 75.9 ± 17.7 kg; and SELF-EV: 72.6 ± 16.9 kg) to Post (CON: 83.4 ± 19.9 kg, effect size (ES): 0.47; SELF: 84 ± 19.1 kg, ES: 0.43; and SELF-EV: 83.2 ± 19.9 kg, ES: 0.57, P < 0.0001). Muscle CSA values increased for all protocols from Pre (CON: 12.09 ± 3.14 cm²; SELF: 11.91 ± 3.71 cm²; and SELF-EV: 11.93 ± 2.32 cm²) to Post (CON: 13.03 ± 3.25 cm², ES: 0.29; SELF: 13.2 ± 4.16 cm², ES: 0.32; and SELF-EV: 13.2 ± 2.35 cm², ES: 0.53, P < 0.0001). No significant differences between protocols were found for both 1-RM and CSA (P > 0.05). Performing RT with SELF, regardless of VL, was equally effective in inducing increases in muscle strength and hypertrophy compared to CON in untrained men.

Progressive Resistance Training Volume: Effects on Muscle Thickness, Mass, and Strength Adaptations in Resistance-Trained Individuals

Aube, D, Wadhi, T, Rauch, J, Anand, A, Barakat, C, Pearson, J, Bradshaw, J, Zazzo, S, Ugrinowitsch, C, and De Souza, EO. Progressive resistance training volume: effects on muscle thickness, mass, and strength adaptations in resistance-trained individuals. J Strength Cond Res XX(X): 000-000, 2020-This study investigated the effects of 12-SET, 18-SET, and 24-SET lower-body weekly sets on muscle strength and mass accretion. Thirty-five resistance-trained individuals (one repetition maximum [1RM] squat: body mass ratio [1RM: BM] = 2.09) were randomly divided into 12-SET: n = 13, 18-SET: n = 12, and 24-SET: n = 10. Subjects underwent an 8-week resistance-training (RT) program consisting of 2 weekly sessions. Muscle strength (1RM), repetitions to failure (RTF) at 70% of 1RM, anterior thigh muscle thickness (MT), at the medial MT (MMT) and distal MT (DMT) points, as well as the sum of both sites (ΣMT), along with region of interest for fat-free mass (ROI-FFM) were measured at baseline and post-testing. For the 1RM, there was a main time effect (p ≤ 0.0001). However, there was a strong trend toward significance (p = 0.052) for group-by-time interaction, suggesting that 18-SET increased 1RM back squat to a greater extent compared with 24-SET, (24-SET: 9.5 kg, 5.4%; 18-SET: 25.5 kg, 16.2%; 12-SET: 18.3 kg, 11.3%). For RTF, only a main time-effect (p ≤ 0.0003) was observed (24-set: 5.7 reps, 33.1%; 18-SET: 2.4 reps, 14.5%; 12-SET: 5.0 reps, 34.8%). For the MMT, DMT, ΣMT, and ROI-FFM, there was only main time-effect (p ≤ 0.0001), (MMT: 24-SET: 0.15 cm, 2.7%; 18-SET: 0.32 cm, 5.7%; 12-SET: 0.38 cm, 6.4%-DMT: 24-set: 0.39 cm, 13.1%; 18-SET: 0.28 cm, 8.9%; 12-SET: 0.34 cm, 9.7%-ΣMT: 24-set: 0.54 cm, 6.1%; 18-SET: 0.60 cm, 6.7%; 12-SET: 0.72 cm, 7.7%, and ROI-FFM: 24-set: 0.70 kg, 2.6%; 18-SET: 1.09 kg, 4.2%; 12-SET: 1.20 kg, 4.6%, respectively). Although all of the groups increased maximum strength, our results suggest that the middle dose range may optimize the gains in back squat 1RM. Our findings also support that differences in weekly set number did not impact in MT and ROI-FFM adaptations in subjects who can squat more than twice their body mass.

The effects of exercise variation in muscle thickness, maximal strength and motivation in resistance trained men

Background

The objective of the present study was to compare the effects of a traditional resistance training program (fixed exercises and repetition ranges) to a resistance training program where exercises and repetition ranges were randomized on a session-by-session basis on markers of muscular adaptations and intrinsic motivation.

Methods

Twenty-one resistance trained men were randomized to perform an 8-week resistance training program using either a fixed exercise selection (CON) or having exercises randomly varied each session via a computerized app. Both groups performed 3 sets of 6 exercises, with training carried out 4 times per week.

Results

Both conditions promoted large, statistically significant increases in the bench press and back-squat 1 repetition maximum without differences between groups. Muscle thickness (MT) measures for the individual quadriceps showed large, statistically significant increases in of the vastus lateralis and rectus femoris for both conditions, with no observed between-group differences. Although no between-group in MT were noted for the vastus intermedius, only the CON displayed significant increases from baseline. Participants in EXP showed a significant, moderate improvement in the intrinsic motivation to training, while participants in the CON group presented non-significant decreases in this variable.

Conclusions

Varying exercise selection had a positive effect on enhancing motivation to train in resistance-trained men, while eliciting similar improvements in muscular adaptations.

Effects of Pre-exhaustion Versus Traditional Resistance Training on Training Volume, Maximal Strength, and Quadriceps Hypertrophy

BACKGROUND

The pre-exhaustion (PreEx) method is used as a resistance training (RT) method to increase muscle mass, yet the chronic effects of this method are poorly understood.

OBJECTIVE

Although readily prescribed as a RT method for promotion of muscle hypertrophy, few researches give light to gains made after chronic PreEx RT. Therefore, we compared the effects of traditional versus PreEx RT programs on muscle strength, body composition, and muscular hypertrophy in adult males.

METHODS

Untrained subjects (age: 31.37 ± 6.83 years; height: 175.29 ± 5.52 cm; body mass: 82.04 ± 13.61 kg; 1RM leg press: 339.86 ± 61.17 kg; 1RM leg extension: 121.71 ± 11.93 kg) were submitted to 9 weeks of RT with weekly sessions. Traditional (TRT) group (n = 12) performed three sets at 45° of leg press exercise at 75% of 1RM, PreEx group (n = 12) completed a set to failure on a leg extension machine prior to the leg press, and the control (CON) group (n = 7) did not train. Maximum strength, muscle thickness, and body composition were analyzed.

RESULTS

PreEx group increased in maximal strength on leg press (16 ± 8%) and leg extension (17 ± 11%), while the TRT group improved by 15 ± 9 and 11 ± 4%, respectively. The thickness of the quadriceps muscles increased for both intervention groups. Specifically, the post-training thickness of the vastus lateralis was significantly higher for PreEx (55%) compared to the CON group. The TRT group presented a greater loss of total and thigh fat mass when compared with the PreEx method. These results were found in the presence of a lower training load for the PreEx group.

CONCLUSION

The PreEx training can decrease the total training volume while maintaining results in strength and hypertrophy when comparing to TRT. However, TRT may be optimal if the goal is to decrease fat mass.

Kettlebell training in clinical practice: a scoping review

BACKGROUND

A scoping review of scientific literature on the effects of kettlebell training. There are no authoritative guidelines or recommendations for using kettlebells within a primary care setting. Our review objectives were to identify the extent, range and nature of the available evidence, to report on the types of evidence currently available to inform clinical practice, to synthesise key concepts, and identify gaps in the research knowledge base.

METHODS

Following the PRISMA-ScR Checklist, we conducted a search of 10 electronic databases from inception to 1 February 2019. There were no exclusions in searching for publications. A single reviewer screened the literature and abstracted data from relevant publications. Articles were grouped and charted by concepts and themes relevant to primary care, and narratively synthesised. Effect sizes from longitudinal studies were identified or calculated, and randomised controlled trials assessed for methodological quality.

RESULTS

Eight hundred and twenty-nine records were identified to 1 February 2019. Four hundred and ninety-six were screened and 170 assessed for eligibility. Ninety-nine publications met the inclusion criteria. Effect sizes were typically trivial to small. One trial used a pragmatic hardstyle training program among healthy college-age participants. Two trials reported the effects of kettlebell training in clinical conditions. Thirty-three studies explicitly used 'hardstyle' techniques and 4 investigated kettlebell sport. Also included were 6 reviews, 22 clinical/expert opinions and 3 case reports of injury. Two reviewers independently evaluated studies using a modified Downs & Black checklist.

CONCLUSIONS

A small number of longitudinal studies, which are largely underpowered and of low methodological quality, provide the evidence-informed therapist with little guidance to inform the therapeutic prescription of kettlebells within primary care. Confidence in reported effects is low to very low. The strength of recommendation for kettlebell training improving measures of physical function is weak, based on the current body of literature. Further research on reported effects is warranted, with inclusion of clinical populations and investigations of musculoskeletal conditions common to primary care. There is a need for an externally valid, standardised approach to the training and testing of kettlebell interventions, which better informs the therapeutic use of kettlebells in primary care.

Evidence of a Ceiling Effect for Training Volume in Muscle Hypertrophy and Strength in Trained Men - Less is More?

PURPOSE

To compare the effects of different resistance training volumes on muscle performance and hypertrophy in trained men.

METHODS

37 volunteers performed resistance training for 24 weeks, divided into groups that performed five (G5), 10 (G10), 15 (G15) and 20 (G20) sets per muscle group per week. Ten repetition maximum (10RM) tests were performed for the bench press, lat pull down, 45º leg press, and stiff legged deadlift. Muscle thickness (MT) was measured using ultrasound at biceps brachii, triceps brachii, pectoralis major, quadriceps femoris and gluteus maximus. All measurements were performed at the beginning (pre) and after 12 (mid) and 24 weeks (post).

RESULTS

All groups showed significant increases in all 10RM tests and MT measures after 12 and 24 weeks when compared to pre (p <0.05). There were no significant differences in any 10RM test or changes between G5 and G10 after 12 and 24 weeks. G5 and G10 showed significantly greater increases for 10RM than G15 and G20 for most exercises at 12 and 24 weeks. There were no group by time interaction for any MT measure.

CONCLUSIONS

The results bring evidence of an inverted "U shaped" curve for the dose response curve for muscle strength. Whilst the same trend was noted for muscle hypertrophy, the results did not reach significance. Five to 10 sets per week might be sufficient for bringing about optimal gains in muscle size and strength in trained men over a 24-week period.

Resistance training frequency and skeletal muscle hypertrophy: A review of available evidence

OBJECTIVES

Current reviews and position stands on resistance training (RT) frequency and associated muscular hypertrophy are based on limited evidence holding implications for practical application and program design. Considering that several recent studies have shed new light on this topic, the present paper aimed to collate the available evidence on RT frequency and the associated effect on muscular hypertrophy.

DESIGN

Review article.

METHODS

Articles for this review were obtained through searches of PubMed/MEDLINE, Scopus, and SPORTDiscus. Both volume-equated (studies in which RT frequency is the only manipulated variable) and non-volume-equated (studies in which both RT frequency and volume are the manipulated variables) study designs were considered.

RESULTS

Ten studies were found that used direct site-specific measures of hypertrophy, and, in general, reported that RT once per week elicits similar hypertrophy compared to training two or three times per week. In addition, 21 studies compared different RT frequencies and used lean body mass devices to estimate muscular growth; most of which reported no significant differences between training frequencies. Five studies were identified that used circumference for estimating muscular growth. These studies provided findings that are difficult to interpret, considering that circumference is a crude measure of hypertrophy (i.e., it does not allow for the differentiation between adipose tissue, intracellular fluids, and muscle mass).

CONCLUSIONS

Based on the results of this review, it appears that under volume-equated conditions, RT frequency does not seem to have a pronounced effect of gains in muscle mass.