A case for considering age and sex when prescribing rest intervals in resistance training

Current resistance training position stands recommend that rest interval duration in resistance training should be prescribed based on the training goal and exercise selection. However, these recommendations are mostly extrapolated from studies that included young men as participants. Therefore, they cannot be generalized to all age groups and all resistance training programs. Herein, two overlooked, but possibly important factors for rest interval prescription are discussed: (1) age, and (2) sex of the individual. Acute studies indicate that older adults, as compared to young adults, require a shorter duration rest interval to achieve recovery between sets. Due to the sex differences in fatigability, it can be speculated that men need a longer duration rest interval than women to maintain high levels of performance. Both sex and age may be relevant variables when determining rest interval duration in resistance exercise and should not be overlooked by exercise practitioners in program design

Dose-response modelling of resistance exercise across outcome domains in strength and conditioning: a meta-analysis.

Resistance exercise is the most common training modality included within strength and conditioning (S&C) practice. Understanding dose-response relationships between resistance training and a range of outcomes relevant to physical and sporting performance is of primary importance for quality S&C prescription. The aim of this meta-analysis was to use contemporary modelling techniques to investigate resistance-only and resistance-dominant training interventions, and explore relationships between training variables (frequency, volume, intensity), participant characteristics (training status, sex) and improvements across a range of outcome domains including maximum strength, power, vertical jump, change of direction, and sprinting performance. Data were obtained from a database of training studies conducted between 1962-2018, which comprised healthy trained or untrained adults engaged in resistance-only or resistance-dominant interventions. Studies were not required to include a control group. Standardized mean difference effect sizes were calculated and interventions categorized according to a range of training variables describing frequency (number of sessions per week), volume (number of sets and repetitions performed), overall intensity (intensity of effort and load, categorised as low, medium, or high), and intensity of load (represented as % 1RM prescribed). Contemporary modelling techniques including Bayesian mixed effects meta-analytic models were fitted to investigate linear and non-linear dose-responses with models compared based on predictive accuracy. Data from a total of 295 studies comprising 535 groups and 6710 participants were included with analyses conducted on time points ≤26 weeks. The best performing model included: duration from baseline, average number of sets, and the main and interaction effects between outcome domain and intensity of load (%1RM) expressed non-linearly. Model performance was not improved by the inclusion of participant training status or sex. The current meta-analysis represents the most comprehensive investigation of dose-response relationships across a range of outcome domains commonly targeted within strength and conditioning to date. Results demonstrate the magnitude of improvements are predominantly influenced by training intensity of load and the outcome measured. When considering the effects of intensity as a %1RM, profiles differ across outcome domains with maximum strength likely to be maximised with the heaviest loads, vertical jump performance likely to be maximised with relatively light loads (~30%1RM), and power likely to be maximised with low to moderate loads (40-70% 1RM)

BCAA supplements are just hype – here’s a better way to build muscles

First paragraph: As gym regulars we never cease to be amazed at the array of post-workout concoctions people consume in the changing room. We see everything from pills and powders to a rainbow of luminous drinks. Mostly it’s with one goal in mind, of course: to obtain muscles as close to the models endorsing these supplements as you possibly can. The global market for sports nutrition products ispredicted tohit $45 billion (£33 billion) by 2022, an increase of about 60% on 2016 value. Previously the domain of bodybuilders and elite athletes, amateur exercisersare becomingbig supplement consumers thanks to the rising popularity of obstacle races, boot camps andCrossFit– all of which the product manufacturers target heavily. One particularly popular variety is products containing branched-chain amino acids (BCAAs). These seem to promise all the benefits of boosting muscle-building after exercise with none of the hassle of foods. But do these products work – or are there better ways to help you get the most out of your gym membership

Effects of range of motion on muscle development during resistance training interventions: A systematic review

The purpose of this study was to systematically review the literature as to the effects of performing exercise with a full versus partial range of motion (ROM) during dynamic, longitudinal resistance training (RT) programs on changes in muscle hypertrophy. Based on the available literature, we aimed to draw evidence-based recommendations for RT prescription. Six studies were identified as meeting inclusion criteria: four of these studies involved RT for the lower limbs while the other two focused on the upper extremities. The total combined sample of the studies was n = 135, which comprised 127 men and 8 women. The methodological quality of all included studies was deemed to be “excellent” based on the modified PEDro scale. When assessing the current body of literature, it can be inferred that performing RT through a full ROM confers beneficial effects on hypertrophy of the lower body musculature versus training with a partial ROM. Alternatively, research on the effects of ROM for the upper limbs is limited and conflicting, precluding the ability to draw strong practical inferences. No study to date has investigated how ROM influences muscle growth of the trunk musculature. Finally, some evidence indicates that the response to variations in ROM may be muscle-specific; however, this hypothesis also warrants further study

A case for considering age and sex when prescribing rest intervals in resistance training

Current resistance training position stands recommend that rest interval duration in resistance training should be prescribed based on the training goal and exercise selection. However, these recommendations are mostly extrapolated from studies that included young men as participants. Therefore, they cannot be generalized to all age groups and all resistance training programs. Herein, two overlooked, but possibly important factors for rest interval prescription are discussed: (1) age, and (2) sex of the individual. Acute studies indicate that older adults, as compared to young adults, require a shorter duration rest interval to achieve recovery between sets. Due to the sex differences in fatigability, it can be speculated that men need a longer duration rest interval than women to maintain high levels of performance. Both sex and age may be relevant variables when determining rest interval duration in resistance exercise and should not be overlooked by exercise practitioners in program design

Isokinetic Dynamometry and 1RM Tests Produce Conflicting Results for Assessing Alterations in Muscle Strength

The purpose of this study was to compare strength gains in the lower limbs, assessed by one maximum repetition (1RM) and isokinetic peak torque (PT), in young men undergoing a resistance training (RT) program. Twenty-seven young men performed resistance training twice a week for 11 weeks. Training involved two exercises for the lower body, two for the upper body and one for the midsection performed with three sets of 8-12 repetitions to momentary muscle failure. Before and after the training period, participants performed the 1RM test in the 45° leg press and knee extension PT in isokinetic dynamometry. The Pearson correlation coefficient was used to assess the relationship between the changes in 1RM and PT, and the Bland-Altman test was performed to check for agreement between the strength changes of both tests. There were significant changes in 1RM and PT of 23.98% and 15.96%, respectively (p \u3c 0.05). The changes in leg press 1RM were significantly higher than the ones in PT. The Bland-Altman analysis revealed that the tests were not equivalent. In conclusion, professionals and researchers involved in strength assessment should be aware that the results obtained by PT and 1RM are not equivalent when evaluating individual responsiveness and/or the efficacy of an intervention on muscle strength, as the results obtained show large variations and can be even conflicting

Effects of a 12-Week Suspension versus Traditional Resistance Training Program on Body Composition, Bioimpedance Vector Patterns, and Handgrip Strength in Older Men: A Randomized Controlled Trial

This investigation aimed to compare the effects of suspension training versus traditional resistance exercise using a combination of bands and bodyweight on body composition, bioimpedance vector patterns, and handgrip strength in older men. Thirty-six older men (age 67.4 ± 5.1 years, BMI 27.1 ± 3.3 kg/m2) were randomly allocated into suspension training (n = 12), traditional training (n = 13), or non-exercise (n = 11) groups over a 12-week study period. Body composition was assessed using conventional bioelectrical impedance analysis and classic and specific bioelectric impedance vector analysis, and handgrip strength was measured with a dynamometer. Results showed a significant (p < 0.05) group by time interaction for fat mass, fat-free mass, total body water, skeletal muscle index, classic and specific bioelectrical resistance, classic bioelectrical reactance, phase angle, and dominant handgrip strength. Classic and specific vector displacements from baseline to post 12 weeks for the three groups were observed. Handgrip strength increased in the suspension training group (p < 0.01, ES: 1.50), remained stable in the traditional training group, and decreased in the control group (p < 0.01, ES: -0.86). Although bodyweight and elastic band training helps to prevent a decline in muscle mass and handgrip strength, suspension training proved more effective in counteracting the effects of aging in older men under the specific conditions studied

Methods matter: the relationship between strength and hypertrophy depends on methods of measurement and analysis

Purpose: The relationship between changes in muscle size and strength may be affected by both measurement and statistical approaches, but their effects have not been fully considered or quantified. Therefore, the purpose of this investigation was to explore how different methods of measurement and analysis can affect inferences surrounding the relationship between hypertrophy and strength gain. Methods: Data from a previous study—in which participants performed eight weeks of elbow flexor training, followed by an eight-week period of detraining—were reanalyzed using different statistical models, including standard between-subject correlations, analysis of covariance, and hierarchical linear modeling. Results: The associative relationship between strength and hypertrophy is highly dependent upon both method/site of measurement and analysis; large differences in variance accounted for (VAF) by the statistical models were observed (VAF = 0– 24.1%). Different sites and measurements of muscle size showed a range of correlations coefficients with one another (r = 0.326–0.945). Finally, exploratory analyses revealed moderate-to-strong relationships between within-individual strength-hypertrophy relationships and strength gained over the training period (ρ = 0.36–0.55). Conclusions: Methods of measurement and analysis greatly influence the conclusions that may be drawn from a given dataset. Analyses that do not account for inter- individual differences may underestimate the relationship between hypertrophy and strength gain, and different methods of assessing muscle size will produce different results. It is suggested that robust experimental designs and analysis techniques, which control for different mechanistic sources of strength gain and inter-individual differences (e.g., muscle moment arms, muscle architecture, activation, and normalized muscle force), be employed in future investigations

Obesity, food intake and exercise: Relationship with ghrelin

Obesity, a disorder of body composition, is defined by a relative or absolute excess of body fat. In general adult population, obesity has been associated with a diverse array of adverse health outcomes, including major causes of death such as cancer, diabetes, cardiovascular disease, as well as functional impairment from problems such as osteoarthritis and sleep apnea. Ghrelin is a newly discovered peptide hormone which plays an important role in obesity. It is a powerful, endogenous orexigenic peptide and has a crucial function in appetite regulation, as well as short – and long-term energy homeostasis. In the presence of increased obesity, decreased physical activity, and high food consumption, the relationship between exercise, appetite, food intake and ghrelin levels has important implications. In this review, we discuss the effect of acute and chronic exercise performance on appetite, food intake and ghrelin and their relationships