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Background: Flywheel resistance training has become more integrated within resistance training programs in a variety of sports due to the neuromuscular, strength, and task-specific enhancements reported with this training. Objective: This paper aimed to present the consensus reached by internationally recognized experts during a meeting on current definitions and guidelines for the implementation of flywheel resistance training technology in sports. Methods: Nineteen experts from different countries took part in the consensus process; 16 of them were present at the consensus meeting (18 May 2023) while three submitted their recommendations by e-mail. Prior to the meeting, evidence summaries were developed relating to areas of priority. This paper discusses the available evidence and consensus process from which recommendations were made regarding the appropriate use of flywheel resistance training technology in sports. The process to gain consensus had five steps: (1) performing a systematic review of systematic reviews, (2) updating the most recent umbrella review published on this topic, (3) first round discussion among a sample of the research group included in this consensus statement, (4) selection of research group members—process of the consensus meeting and formulation of the recommendations, and (5) the consensus process. The systematic analysis of the literature was performed to select the most up-to-date review papers available on the topic, which resulted in nine articles; their methodological quality was assessed according to AMSTAR 2 (Assessing the Methodological Quality of Systematic Review 2) and GRADE (Grading Recommendations Assessment Development and Evaluation). Statements and recommendations scoring 7–9 were considered appropriate. Results: The recommendations were based on the evidence summary and researchers' expertise; the consensus statement included three statements and seven recommendations for the use of flywheel resistance training technology. These statements and recommendations were anonymously voted on and qualitatively analyzed. The three statements reported a score ranging from 8.1 to 8.8, and therefore, all statements included in this consensus were considered appropriate. The recommendations (1–7) had a score ranging from 7.7 to 8.6, and therefore, all recommendations were considered appropriate. Conclusions: Because of the consensus achieved among the experts in this project, it is suggested that practitioners and researchers should adopt the guidelines reported in this consensus statement regarding the use of flywheel resistance technology in sports. [ABSTRACT FROM AUTHOR]

Background: Developing the sprint performance of field-based invasion team sport (FITS) players is considered an essential training goal for FITS coaching practitioners, and thus numerous training methods are employed to elicit improvements. Although interest in resisted sprint training (RST) has grown considerably in recent times, there remains a lack of clarity around its utility in FITS, particularly regarding the use and effectiveness of heavier RST loads. Objectives: The aims of this review were to (1) compare RST to unresisted sprinting, (2) examine if RST can improve sprint performance and (3) investigate if external load and the method of load prescription influence the impact of RST in FITS players. Methods: The systematic review and meta-analysis were conducted in compliance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The search strategy included terms for RST, RST modalities and FITS, and was applied to PubMed, SPORTDiscus, Web of Science and OpenGrey databases. Methodological quality and risk of bias associated with each study were assessed using the Physiotherapy Evidence Database scale (PEDro) and Cochrane Risk of Bias assessment tool respectively. Results: Twenty-one studies met the inclusion criteria for this review and were included in the final analysis. The primary between-group analysis revealed no differences between RST and unresisted sprinting for developing the early acceleration, late acceleration and maximum velocity sprint phases. Secondly, a within-group analysis found significant improvements for resisted sprint training in the early acceleration (standardised mean difference [SMD] − 0.80) and late acceleration (SMD − 0.28) sprint phases, with no change detected for the maximum velocity phase. Finally, significant moderate improvements were found for light (SMD − 0.69) and very heavy (SMD − 1.01) loads during early acceleration. Conclusions: Resisted sprint training achieved similar improvements in sprint performance to those found for unresisted sprinting during the acceleration and maximum velocity sprint phases. Within-group findings show RST is an effective method for improving early acceleration and late acceleration performance of FITS players. Finally, a subgroup analysis supports the use of light and very heavy loads for increasing early acceleration performance, while also highlighting greater benefits associated with using the percentage velocity decrement loading method. Clinical Trial Registration: Open Science Framework, https://osf.io/thms7/. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

It is hypothesized that there is likely a finite ability for muscular adaptation. While it is difficult to distinguish between a true plateau following a long-term training period and short-term stalling in muscle growth, a plateau in muscle growth has been attributed to reaching a genetic potential, with limited discussion on what might physiologically contribute to this muscle growth plateau. The present paper explores potential physiological factors that may drive the decline in muscle growth after prolonged resistance training. Overall, with chronic training, the anabolic signaling pathways may become more refractory to loading. While measures of anabolic markers may have some predictive capabilities regarding muscle growth adaptation, they do not always demonstrate a clear connection. Catabolic processes may also constrain the ability to achieve further muscle growth, which is influenced by energy balance. Although speculative, muscle cells may also possess cell scaling mechanisms that sense and regulate their own size, along with molecular brakes that hinder growth rate over time. When considering muscle growth over the lifespan, there comes a point when the anabolic response is attenuated by aging, regardless of whether or not individuals approach their muscle growth potential. Our goal is that the current review opens avenues for future experimental studies to further elucidate potential mechanisms to explain why muscle growth may plateau. [ABSTRACT FROM AUTHOR]

Background: Two specific sprint training methods that are present to varying degrees in research and practice are combined uphill–downhill sprinting (UDS) and resisted sprint training methods (RS). Both methods seem to improve sprint performance, but to the author's knowledge a comparison does not exist investigating the differences between the two training protocols and traditional sprinting. Objective: The present systematic review and meta-analysis investigated sprint performance changes between combined uphill–downhill sprinting and resisted sprinting methods (sleds, cables/bands, vests, uphill) and how these compared with traditional sprinting. Methods: A literature search was performed on 19 December 2022, in the databases PubMed, SPORTDiscus, Web of Science and SCOPUS, which from 22 studies yielded a total of 24 eligible groups (UDS, n = 6; RS, n = 18). Studies that measured sprint performance, had a traditional sprinting control, and used either training intervention in healthy individuals of any age for ≥ 4 weeks were eligible for the meta-analysis. The change in sprint performance from baseline to post intervention was compared between the interventions and their traditional sprinting control group. Outcomes were expressed as standardized mean differences (SMD). Results: The standardized changes in sprint performance between intervention groups and traditional-sprinting controls (negative in favour of intervention, positive in favour of traditional sprint) and 95% confidence interval (CI) were as follows: small for UDS (SMD − 0.41 [− 0.79, − 0.03]; p = 0.03), trivial for RS (SMD − 0.14 [− 0.36, 0.07]; p = 0.19). Conclusion: Combined uphill–downhill sprinting was more effective than traditional sprinting, while resisted sprinting was not. It appears that resisted sprint interventions do not increase sprint performance any more than traditional sprinting. Subgroup analysis and meta-regression appear to show differences between sled loads and possible differences across distances tested. The results of this review and meta-analysis seem to warrant further investigations into the possibility that UDS may be a superior sprint training method to resisted and traditional sprinting. [ABSTRACT FROM AUTHOR]

Background: Resistance exercise training is widely used by general and athletic populations to increase skeletal muscle hypertrophy, power and strength. Endogenous sex hormones influence various bodily functions, including possibly exercise performance, and may influence adaptive changes in response to exercise training. Hormonal contraceptive (HC) use modulates the profile of endogenous sex hormones, and therefore, there is increasing interest in the impact, if any, of HC use on adaptive responses to resistance exercise training. Objective: Our aim is to provide a quantitative synthesis of the effect of HC use on skeletal muscle hypertrophy, power and strength adaptations in response to resistance exercise training. Methods: A systematic review with meta-analysis was conducted on experimental studies which directly compared skeletal muscle hypertrophy, power and strength adaptations following resistance exercise training in hormonal contraceptive users and non-users conducted before July 2023. The search using the online databases PUBMED, SPORTDiscus, Web of Science, Embase and other supplementary search strategies yielded 4669 articles, with 8 articles (54 effects and 325 participants) meeting the inclusion criteria. The methodological quality of the included studies was assessed using the "Tool for the assessment of study quality and reporting in exercise". Results: All included studies investigated the influence of oral contraceptive pills (OCP), with no study including participants using other forms of HC. The articles were analysed using a meta-analytic multilevel maximum likelihood estimator model. The results indicate that OCP use does not have a significant effect on hypertrophy [0.01, 95% confidence interval (CI) [− 0.11, 0.13], t = 0.14, p = 0.90), power (− 0.04, 95% CI [− 0.93, 0.84], t = − 0.29, p = 0.80) or strength (0.10, 95% CI [− 0.08, 0.28], t = 1.48, p = 0.20). Discussion: Based on the present analysis, there is no evidence-based rationale to advocate for or against the use of OCPs in females partaking in resistance exercise training to increase hypertrophy, power and/or strength. Rather, an individualised approach considering an individual's response to OCPs, their reasons for use and menstrual cycle history may be more appropriate. Registration: The review protocol was registered on PROSPERO (ID number and hyperlink: CRD42022365677). [ABSTRACT FROM AUTHOR]

Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models. [ABSTRACT FROM AUTHOR]

Background: The primary aim of our systematic review and meta-analysis was to investigate the effect of resistance training on academic outcomes in school-aged youth. Methods: We conducted a systematic search of six electronic databases (CINAHL Complete, PsycINFO, SCOPUS, Ovid MEDLINE, SPORTDiscus and EMBASE) with no date restrictions. Studies were eligible if they: (a) included school-aged youth (5–18 years), and (b) examined the effect of resistance training on academic outcomes (i.e., cognitive function, academic achievement, and/or on-task behaviour in the classroom). Risk of bias was assessed using the appropriate Cochrane Risk of Bias Tools, funnel plots and Egger's regression asymmetry tests. A structural equation modelling approach was used to conduct the meta-analysis. Results: Fifty-three studies were included in our systematic review. Participation in resistance training (ten studies with 53 effect sizes) had a small positive effect on the overall cognitive, academic and on-task behaviours in school-aged youth (standardized mean difference (SMD) 0.19, 95% confidence interval (CI) 0.05–0.32). Resistance training was more effective (SMD 0.26, 95% CI 0.10–0.42) than concurrent training, i.e., the combination of resistance training and aerobic training (SMD 0.11, 95% CI − 0.05–0.28). An additional 43 studies (including 211 effect sizes) examined the association between muscular fitness and cognition or academic achievement, also yielding a positive relationship (SMD 0.13, 95% CI 0.10–0.16). Conclusion: This review provides preliminary evidence that resistance training may improve cognitive function, academic performance, and on-task behaviours in school-aged youth. PROSPERO Registration: CRD42020175695. [ABSTRACT FROM AUTHOR]

Background: Well programmed strength and conditioning training is an indispensable part of the long-term training process for athletes in individual and team sports to improve performance and prevent injuries. Yet, there is a limited number of studies available that examine the effects of resistance training (RT) on muscular fitness and physiological adaptations in elite female athletes. Objectives: This systematic review aimed to summarize recent evidence on the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes. Materials and Methods: A systematic literature search was conducted in nine electronic databases (Academic Search Elite, CINAHL, ERIC, Open Access Theses and Dissertations, Open Dissertations, PsycINFO, PubMed/MEDLINE, Scopus, and SPORTDiscus) from inception until March 2022. Key search terms from the MeSH database such as RT and strength training were included and combined using the operators "AND," "OR," and "NOT". The search syntax initially identified 181 records. After screening for titles, abstracts, and full texts, 33 studies remained that examined the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes. Results: Twenty-four studies used single-mode RT or plyometric training and nine studies investigated the effects of combined training programs such as resistance with plyometric or agility training, resistance and speed training, and resistance and power training. The training duration lasted at least 4 weeks, but most studies used ~ 12 weeks. Studies were generally classified as 'high-quality' with a mean PEDro score of 6.8 (median 7). Irrespective of the type or combination of RT with other strength-dominated exercise regimens (type of exercise, exercise duration, or intensity), 24 out of 33 studies reported increases in muscle power (e.g., maximal and mean power; effect size [ES]: 0.23 < Cohen's d < 1.83, small to large), strength (e.g., one-repetition-maximum [1RM]; ES: 0.15 < d < 6.80, small to very large), speed (e.g., sprint times; ES: 0.01 < d < 1.26, small to large), and jump performance (e.g., countermovement/squat jump; ES: 0.02 < d < 1.04, small to large). The nine studies that examined the effects of combined training showed significant increases on maximal strength (ES: 0.08 < d < 2.41, small to very large), muscle power (ES: 0.08 < d < 2.41, small to very large), jump and sprint performance (ES: 0.08 < d < 2.41, small to very large). Four out of six studies observed no changes in body mass or percentage of body fat after resistance or plyometric training or combined training (ES: 0.026 < d < 0.492, small to medium). Five out of six studies observed significant changes in muscle morphology (e.g., muscle thickness, muscle fiber cross-sectional area; ES: 0.23 < d < 3.21, small to very large). However, one study did not find any changes in muscle morphology (i.e., muscle thickness, pennation angle; ES: 0.1 < d < 0.19, small). Conclusion: Findings from this systematic review suggest that RT or combined RT with other strength-dominated exercise types leads to significant increases in measures of muscle power, strength, speed, and jump performance in elite female athletes. However, the optimal dosage of programming parameters such as training intensity and duration necessary to induce large effects in measures of muscular fitness and their physiological adaptations remain to be resolved in female elite athletes. [ABSTRACT FROM AUTHOR]

Eccentric resistance exercise emphasizes active muscle lengthening against resistance. In the past 15 years, researchers and practitioners have expressed considerable interest in accentuated eccentric (i.e., eccentric overload) and eccentric-only resistance exercise as strategies for enhancing performance and preventing and rehabilitating injuries. However, delivery of eccentric resistance exercise has been challenging because of equipment limitations. Previously, we briefly introduced the concept of connected adaptive resistance exercise (CARE)—the integration of software and hardware to provide a resistance that adjusts in real time and in response to the individual's volitional force within and between repetitions. The aim of the current paper is to expand this discussion and explain the potential for CARE technology to improve the delivery of eccentric resistance exercise in various settings. First, we overview existing resistance exercise equipment and highlight its limitations for delivering eccentric resistance exercise. Second, we describe CARE and explain how it can accomplish accentuated eccentric and eccentric-only resistance exercise in a new way. We supplement this discussion with preliminary data collected with CARE technology in laboratory and non-laboratory environments. Finally, we discuss the potential for CARE technology to deliver eccentric resistance exercise for various purposes, e.g., research studies, rehabilitation programs, and home-based or telehealth interventions. Overall, CARE technology appears to permit completion of eccentric resistance exercise feasibly in both laboratory and non-laboratory environments and thus has implications for researchers and practitioners in the fields of sports medicine, physiotherapy, exercise physiology, and strength and conditioning. Nevertheless, formal investigations into the impact of CARE technology on participation in eccentric resistance exercise and clinical outcomes are still required. [ABSTRACT FROM AUTHOR]

Background: Dysfunction of the endothelium is a key precursor of cardiovascular disease. Endothelial function, as assessed via the flow-mediated dilation test, is attenuated with chronic disease (e.g., type 2 diabetes mellitus, hypertension). Exercise training may mitigate this dysfunction and promote better vascular health. Objective: The main objective of this umbrella review was to determine the impact of exercise training on flow-mediated dilation in healthy adults and those with chronic disease. Methods: Studies were included if they conducted a systematic review and/or meta-analysis on flow-mediated dilation responses to exercise interventions in adults. Sources were searched in January 2022 and included Scopus, EMBASE, MEDLINE, CINAHL, and Academic Search Premier. National Institutes of Health quality assessment tools were used. The results were presented narratively. Results: Twenty-seven systematic reviews, including 19 meta-analyses, (total: 5464 unique participants, 2181 reported unique female individuals) met the inclusion criteria. The average overall quality of included reviews was 8.8/11. The quality of studies within each included review varied from low to moderate using a variety of quality assessment scales. Reviews were conducted in healthy adults (n = 9, meta-analyses = 6), as well as those with type 2 diabetes (n = 5, meta-analyses = 4), cardiovascular conditions [i.e., conditions that impact the cardiovascular system, but excluding samples of only type 2 diabetes] (n = 11, meta-analyses = 7), and other chronic conditions (n = 2, meta-analyses = 2). Overall, the included reviews provided evidence that the type of training to optimally improve FMD may vary based on disease condition. Specifically, the evidence suggests that healthy adults benefitted most from higher intensity aerobic training and/or more frequent low-to-moderate resistance training. In addition, adults with type 2 diabetes benefitted most from low-intensity resistance or aerobic exercise training, whereas those with cardiovascular conditions should consider engaging in high-intensity aerobic training to improve endothelial function. Conclusions: This information may help guide the design of specific exercise programs or recommendations for adults with chronic conditions. [ABSTRACT FROM AUTHOR]

Background: There has been a rise in the participation, professionalism, and profile of female sports in recent years. Sprinting ability is an important quality for successful athletic performance in many female team sports. However, much of the research to date on improving sprint performance in team sports is derived from studies with male participants. Given the biological differences between the sexes, this may be problematic for practitioners when programming to enhance sprint performance in female team-sport athletes. Therefore, the aims of this systematic review were to investigate (1) the overall effect of lower body strength training on sprint performance, and (2) the effect of specific strength training modalities (i.e., reactive-; maximal-; combined-; special-strength) on sprint performance in female team-sport athletes. Methods: An electronic database search was performed using PubMed, MEDLINE, SPORTDiscus, CINAHL, The Cochrane Library, and SCOPUS to identify relevant articles. A random-effects meta-analysis was performed to establish standardised mean difference with 95% confidence intervals and the magnitude and direction of the effect. Results: Fifteen studies were included in the final analysis. The 15 studies represent a total sample size of 362 participants (intervention n = 190; control n = 172) comprising 17 intervention groups and 15 control groups. The overall effects revealed small improvements in sprint performance in favour of the experimental group over 0–10 m and moderate improvements over sprint distances of 0–20 m and 0–40 m. The magnitude of improvement in sprint performance was influenced by the strength modality (i.e., reactive-, maximal-, combined-, and special-strength) utilised in the intervention. Reactive- and combined-strength training methods had a greater effect than maximal- or special-strength modalities on sprint performance. Conclusion: This systematic review and meta-analysis demonstrated that, when compared with a control group (i.e., technical and tactical training), the different strength training modalities exhibited small to moderate improvements in sprint performance in female team-sport athletes. The results of a moderator analysis demonstrated that youth athletes (< 18 years) yielded a greater improvement in sprint performance compared with adults (≥ 18 years). This analysis also supports the use of a longer programme duration (> 8 weeks) with a higher total number of training sessions (> 12 sessions) to improve overall sprint performance. These results will serve to guide practitioners when programming to enhance sprint performance in female team-sport athletes. [ABSTRACT FROM AUTHOR]

Background: The current literature on the chronic effects of static stretching (SS) exercises on muscle strength and power is unclear and controversial. Objective: We aimed to examine the chronic effects of SS exercises on muscle strength and power as well as flexibility in healthy individuals across the lifespan. Design: Systematic review with meta-analysis of (randomized) controlled trials. Data Sources: A systematic literature search was conducted in the databases PubMed, Web of Science, Cochrane Library, and SPORTDiscus up to May 2022. Eligibility Criteria for Selecting Studies: We included studies that investigated the chronic effects of SS exercises on at least one muscle strength and power outcome compared to an active/passive control group or the contralateral leg (i.e., using between- or within-study designs, respectively) in healthy individuals, irrespective of age, sex, and training status. Results: The main findings of 41 studies indicated trivial-to-small positive effects of chronic SS exercises on muscle strength (standardized mean difference [SMD] = 0.21, [95% confidence interval 0.10–0.32], p = 0.001) and power (SMD = 0.19, 95% confidence interval 0.12–0.26], p < 0.001). For flexibility, moderate-to-large increases were observed (SMD = 0.96, [95% confidence interval 0.70–1.22], p < 0.001). Subgroup analyses, taking the participants' training status into account, revealed a larger muscle strength improvement for sedentary (SMD = 0.58, p < 0.001) compared with recreationally active participants (SMD = 0.16, p = 0.029). Additionally, larger flexibility gains were observed following passive (SMD = 0.97, p < 0.001) compared with active SS exercises (SMD = 0.59, p = 0.001). The chronic effects of SS on muscle strength were moderated by the proportion of female individuals in the sample (β = 0.004, p = 0.042), with higher proportions experiencing larger gains. Other moderating variables included mean age (β = 0.011, p < 0.001), with older individuals showing larger muscle strength gains, and the number of repetitions per stretching exercise and session (β = 0.023, p = 0.004 and β = 0.013, p = 0.008, respectively), with more repetitions associated with larger muscle strength improvements. Muscle power was also moderated by mean age (β = 0.006, p = 0.007) with larger gains in older individuals. The meta-regression analysis indicated larger flexibility gains with more repetitions per session (β = 0.094, p = 0.016), more time under stretching per session (β = 0.090, p = 0.026), and more total time under stretching (β = 0.078, p = 0.034). Conclusions: The main findings indicated that chronic SS exercises have the potential to improve muscle strength and power. Such improvements appear to benefit sedentary more than recreationally active participants. Likewise, chronic SS exercises result in a marked enhancement in flexibility with larger effects of passive, as compared with active, SS. The results of the meta-regression analysis for muscle strength indicated larger benefits of chronic SS exercises in samples with higher proportions of female, older participants, and a higher number of repetitions per stretching exercise and session. For muscle power, results suggested larger gains for older participants. Regarding flexibility, findings indicated larger benefits following a higher number of repetitions per exercise and a longer time under stretching per session as well as a longer total time under stretching. [ABSTRACT FROM AUTHOR]

Background: Although it is known that resistance training can be as effective as stretch training to increase joint range of motion, to date no comprehensive meta-analysis has investigated the effects of resistance training on range of motion with all its potential affecting variables. Objective: The objective of this systematic review with meta-analysis was to evaluate the effect of chronic resistance training on range of motion compared either to a control condition or stretch training or to a combination of resistance training and stretch training to stretch training, while assessing moderating variables. Design: For the main analysis, a random-effect meta-analysis was used and for the subgroup analysis a mixed-effect model was implemented. Whilst subgroup analyses included sex and participants' activity levels, meta-regression included age, frequency, and duration of resistance training. Data Sources: Following the systematic search in four databases (PubMed, Scopus, SPORTDiscus, and Web of Science) and reference lists, 55 studies were found to be eligible. Eligibility Criteria: Controlled or randomized controlled trials that separately compared the training effects of resistance training exercises with either a control group, stretching group, or combined stretch and resistance training group on range of motion in healthy participants. Results: Resistance training increased range of motion (effect size [ES] = 0.73; p < 0.001) with the exception of no significant range of motion improvement with resistance training using only body mass. There were no significant differences between resistance training versus stretch training (ES = 0.08; p = 0.79) or between resistance training and stretch training versus stretch training alone (ES = − 0.001; p = 0.99). Although "trained or active people" increased range of motion (ES = 0.43; p < 0.001) "untrained and sedentary" individuals had significantly (p = 0.005) higher magnitude range of motion changes (ES = 1.042; p < 0.001). There were no detected differences between sex and contraction type. Meta-regression showed no effect of age, training duration, or frequency. Conclusions: As resistance training with external loads can improve range of motion, stretching prior to or after resistance training may not be necessary to enhance flexibility. [ABSTRACT FROM AUTHOR]

Background and Objective: This systematic review with meta-analysis investigated the influence of resistance training proximity-to-failure on muscle hypertrophy. Methods: Literature searches in the PubMed, SCOPUS and SPORTDiscus databases identified a total of 15 studies that measured muscle hypertrophy (in healthy adults of any age and resistance training experience) and compared resistance training performed to: (A) momentary muscular failure versus non-failure; (B) set failure (defined as anything other than momentary muscular failure) versus non-failure; or (C) different velocity loss thresholds. Results: There was a trivial advantage for resistance training performed to set failure versus non-failure for muscle hypertrophy in studies applying any definition of set failure [effect size=0.19 (95% confidence interval 0.00, 0.37), p=0.045], with no moderating effect of volume load (p=0.884) or relative load (p=0.525). Given the variability in set failure definitions applied across studies, sub-group analyses were conducted and found no advantage for either resistance training performed to momentary muscular failure versus non-failure for muscle hypertrophy [effect size=0.12 (95% confidence interval −0.13, 0.37), p=0.343], or for resistance training performed to high (>25%) versus moderate (20–25%) velocity loss thresholds [effect size=0.08 (95% confidence interval −0.16, 0.32), p=0.529]. Conclusion: Overall, our main findings suggest that (i) there is no evidence to support that resistance training performed to momentary muscular failure is superior to non-failure resistance training for muscle hypertrophy and (ii) higher velocity loss thresholds, and theoretically closer proximities-to-failure do not always elicit greater muscle hypertrophy. As such, these results provide evidence for a potential non-linear relationship between proximity-to-failure and muscle hypertrophy. [ABSTRACT FROM AUTHOR]

Background: Skeletal muscle has extraordinary regenerative capabilities against challenge, mainly owing to its resident muscle stem cells, commonly identified by Pax7+, which expediently donate nuclei to the regenerating multinucleated myofibers. This local reserve of stem cells in damaged muscle tissues is replenished by undifferentiated bone marrow stem cells (CD34+) permeating into the surrounding vascular system. Objective: The purpose of the study was to provide a quantitative estimate for the changes in Pax7+ muscle stem cells (satellite cells) in humans following an acute bout of exercise until 96 h, in temporal relation to circulating CD34+ bone marrow stem cells. A subgroup analysis of age was also performed. Methods: Four databases (Web of Science, PubMed, Scopus, and BASE) were used for the literature search until February 2022. Pax7+ cells in human skeletal muscle were the primary outcome. Circulating CD34+ cells were the secondary outcome. The standardized mean difference (SMD) was calculated using a random-effects meta-analysis. Subgroup analyses were conducted to examine the influence of age, training status, type of exercise, and follow-up time after exercise. Results: The final search identified 20 studies for Pax7+ cells comprising a total of 370 participants between the average age of 21 and 74 years and 26 studies for circulating CD34+ bone marrow stem cells comprising 494 participants between the average age of 21 and 67 years. Only one study assessed Pax7+ cells immediately after aerobic exercise and showed a 32% reduction in exercising muscle followed by a fast repletion to pre-exercise level within 3 h. A large effect on increasing Pax7+ cell content in skeletal muscles was observed 24 h after resistance exercise (SMD = 0.89, p < 0.001). Pax7+ cells increased to ~ 50% above pre-exercise level 24–72 h after resistance exercise. For a subgroup analysis of age, a large effect (SMD = 0.81, p < 0.001) was observed on increasing Pax7+ cells in exercised muscle among adults aged > 50 years, whereas adults at younger age presented a medium effect (SMD = 0.64, p < 0.001). Both resistance exercise and aerobic exercise showed a medium overall effect in increasing circulating CD34+ cells (SMD = 0.53, p < 0.001), which declined quickly to the pre-exercise baseline level after exercise within 6 h. Conclusions: An immediate depletion of Pax7+ cells in exercising skeletal muscle concurrent with a transient release of CD34+ cells suggest a replenishment of the local stem cell reserve from bone marrow. A protracted Pax7+ cell expansion in the muscle can be observed during 24–72 h after resistance exercise. This result provides a scientific basis for exercise recommendations on weekly cycles allowing for adequate recovery time. Exercise-induced Pax7+ cell expansion in muscle remains significant at higher age, despite a lower stem cell reserve after age 50 years. More studies are required to confirm whether Pax7+ cell increment can occur after aerobic exercise. Clinical Trial Registration: Registered at the International Prospective Register of Systematic Reviews (PROSPERO) [identification code CRD42021265457]. [ABSTRACT FROM AUTHOR]

Background: Velocity loss (VL) experienced in a set during resistance training is often monitored to control training volume and quantify acute fatigue responses. Accordingly, various VL thresholds are used to prescribe resistance training and target different training adaptations. However, there are inconsistencies in the current body of evidence regarding the magnitude of the acute and chronic responses to the amount of VL experienced during resistance training. Objective: The aim of this systematic review was to (1) evaluate the acute training volume, neuromuscular, metabolic, and perceptual responses to the amount of VL experienced during resistance training; (2) synthesize the available evidence on the chronic effects of different VL thresholds on training adaptations; and (3) provide an overview of the factors that might differentially influence the magnitude of specific acute and chronic responses to VL during resistance training. Methods: This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Five databases were searched, and studies were included if they were written in English, prescribed resistance training using VL, and evaluated at least one (1) acute training volume, neuromuscular, metabolic, or perceptual response or (2) training adaptation. Risk of bias was assessed using a modified Cochrane Collaboration's tool for assessing the risk of bias in randomized trials. Multilevel and multivariate meta-regressions were performed where possible. Results: Eighteen acute and 19 longitudinal studies met the inclusion criteria, of which only one had more than one risk of bias item assessed as high risk. Based on the included acute studies, it seems that the number of repetitions per set, blood lactate concentration, and rating of perceived exertion generally increase, while countermovement jump height, running sprint times, and velocity against fixed loads generally decrease as VL increases. However, the magnitude of these effects seems to be influenced, among other factors, by the exercise and load used. Regarding training adaptations, VL experienced during resistance training did not influence muscle strength and endurance gains. Increases in VL were associated with increases in hypertrophy (b = 0.006; 95% confidence interval [CI] 0.001, 0.012), but negatively affected countermovement jump (b = − 0.040; 95% CI − 0.079, − 0.001), sprint (b = 0.001; 95% CI 0.001, 0.002), and velocity against submaximal load performance (b = − 0.018; 95% CI − 0.029, − 0.006). Conclusions: A graded relationship exists between VL experienced during a set and acute training volume, neuromuscular, metabolic, and perceptual responses to resistance training. However, choice of exercise, load, and individual trainee characteristics (e.g., training history) seem to modulate these relationships. The choice of VL threshold does not seem to affect strength and muscle endurance gains whereas higher VL thresholds are superior for enhancing hypertrophy, and lower VL thresholds are superior for jumping, sprinting, and velocity against submaximal loads performance. Clinical Trial Registration: The original protocol was prospectively registered (https://osf.io/q4acs/) with the Open Science Framework. [ABSTRACT FROM AUTHOR]

Objective: Body mass (BM) loss and body composition (BC) changes threaten astronauts' health and mission success. However, the energetic contribution of the exercise countermeasure to these changes has never been investigated during long-term missions. We studied energy balance and BC in astronauts during 6-month missions onboard the International Space Station. Methods: Before and after at least 3 months in space, BM, BC, total and activity energy expenditure (TEE and AEE) were measured using the doubly labeled water method in 11 astronauts (2011–2017). Physical activity (PA) was assessed by the SensewearPro® activity-device. Results: Three-month spaceflight decreased BM (− 1.20 kg [SE 0.5]; P = 0.04), mainly due to non-significant fat-free mass loss (FFM; − 0.94 kg [0.59]). The decrease in walking time (− 63.2 min/day [11.5]; P < 0.001) from preflight was compensated by increases in non-ambulatory activities (+ 64.8 min/day [18.8]; P < 0.01). Average TEE was unaffected but a large interindividual variability was noted. Astronauts were stratified into those who maintained (stable_TEE; n = 6) and those who decreased (decreased_TEE; n = 5) TEE and AEE compared to preflight data. Although both groups lost similar BM, FFM was maintained and FM reduced in stable_TEE astronauts, while FFM decreased and FM increased in decreased_TEE astronauts (estimated between-group-difference (EGD) in ΔFFMindex [FFMI] 0.87 kg/m2, 95% CI + 0.32 to + 1.41; P = 0.01, ΔFMindex [FMI] − 1.09 kg/m2, 95% CI − 2.06 to − 0.11 kg/m2; P = 0.03). The stable_TEE group had higher baseline FFMI, and greater baseline and inflight vigorous PA than the decreased_TEE group (P < 0.05 for all). ΔFMI and ΔFFMI were respectively negatively and positively associated with both ΔTEE and ΔAEE. Conclusion: Both ground fitness and inflight overall PA are associated with spaceflight-induced TEE and BC changes and thus energy requirements. New instruments are needed to measure real-time individual changes in inflight energy balance components. [ABSTRACT FROM AUTHOR]

There is an increasing interest in female athletic performance—especially concerning the impact of the female menstrual cycle on training response. Indeed, fluctuations in female sex hormones, estrogen and progesterone, during the menstrual cycle regulate protein metabolism and recovery processes in skeletal muscle and may thus impact exercise training-related outcomes. Studies demonstrate that anaerobic capacity and muscle strength are greatest during the follicular phase of the menstrual cycle, when estrogen levels peak. In addition, studies indicate that resistance training conducted in the follicular phase of the menstrual cycle (follicular phase-based resistance training) may be superior to luteal phase-based training in terms of enhancing muscle strength and mass. This raises the possibility that the physiological capabilities of skeletal muscle to adapt to exercise training are dependent on the menstrual cycle and can be important for female athletes in optimizing their training. In this paper, we critically review the current state of the art concerning the impact of menstrual cycle phase-based resistance training and highlight why follicular phase-based resistance training possibly is superior to luteal phase-based training in enhancing resistance training outcomes. Finally, we identify directions for further research. [ABSTRACT FROM AUTHOR]

Gestational diabetes mellitus (GDM) poses a significant health concern for both mother and offspring. Exercise has emerged as a cornerstone of glycemic management in GDM. However, most research regarding this topic examines aerobic training (AT), despite substantial evidence for the effectiveness of resistance training (RT) in improving dysregulated glucose in other groups of people with diabetes, such as in type 2 diabetes mellitus (T2DM). Thus, the purpose of this paper is to review research that examined the impact of RT on markers of glucose management in GDM, and to discuss future research directions to determine the benefits of RT in GDM. Based on the current evidence, RT is effective in reducing insulin requirement, especially in overweight women, reducing fasting glucose concentrations, and improving short-term postprandial glycemic control. However, the number of studies and findings limit conclusions about the impact of RT on risk of GDM, fasting insulin concentrations, insulin resistance, β-cell function, and intra-exercise glucose management. Overall, current evidence is accumulating to suggest that RT is a promising non-pharmacological tool to regulate circulating glucose concentrations in women with GDM, and a potential alternative or supplement to AT. [ABSTRACT FROM AUTHOR]

A correction is presented to the article titled "Effects of Combined Uphill–Downhill Sprinting Versus Resisted Sprinting Methods on Sprint Performance: A Systematic Review and Meta‑analysis," which appeared in the Sports Medicine journal in 2024.

The primary aim of this narrative review was to outline the historical genesis of resistance training strategies that incorporate high-load, low-velocity exercises and low-load, high-velocity exercises in the same training session allowing for different "exercise sequences" to be simultaneously implemented. Discrepancies between scientific works and the terminology used within contemporary sport science publications are identified. Upon review of the literature, we propose "complex training" to be considered an umbrella term with 4 different implementations, generally used to indicate a method in which movement velocity or load is altered between sets and/or exercises within the same session with the aim of improving slow and fast force expression. We propose the following terminology for said implementations: contrast training—exercise sequence with alternating high-load and low-load (higher-velocity) exercises in a set-by-set fashion within the same session (corresponding with 'contrast pairs' and 'intra-contrast rest'); descending training—several sets of high-load (e.g., back squat) exercises completed before the execution of several sets of low-load, higher-velocity (e.g., vertical jump) exercises within the same session; ascending training—several sets of low-load, higher-velocity exercises completed before several sets of high-load exercises within the same session; and French contrast training—subset of contrast training in which a series of exercises are performed in sequence within a single session: heavy compound exercise, plyometric exercise, light-to-moderate load compound exercise that maximises movement speed (i.e., external power), and a plyometric exercise (often assisted). Finally, practical applications and training considerations are presented. [ABSTRACT FROM AUTHOR]

Background: Older adults experience considerable muscle and bone loss that are closely interconnected. The efficacy of progressive resistance training programs to concurrently reverse/slow the age-related decline in muscle strength and bone mineral density (BMD) in older adults remains unclear. Objectives: We aimed to quantify concomitant changes in lower-body muscle strength and BMD in older adults following a progressive resistance training program and to determine how these changes are influenced by mode (resistance only vs. combined resistance and weight-bearing exercises), frequency, volume, load, and program length. Methods: MEDLINE/PubMed and Embase databases were searched for articles published in English before 1 June, 2021. Randomized controlled trials reporting changes in leg press or knee extension one repetition maximum and femur/hip or lumbar spine BMD following progressive resistance training in men and/or women ≥ 65 years of age were included. A random-effects meta-analysis and meta-regression determined the effects of resistance training and the individual training characteristics on the percent change (∆%) in muscle strength (standardized mean difference) and BMD (mean difference). The quality of the evidence was assessed using the Cochrane risk-of-bias tool (version 2.0) and Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria. Results: Seven hundred and eighty studies were identified and 14 were included. Progressive resistance training increased muscle strength (∆ standardized mean difference = 1.1%; 95% confidence interval 0.73, 1.47; p ≤ 0.001) and femur/hip BMD (∆ mean difference = 2.77%; 95% confidence interval 0.44, 5.10; p = 0.02), but not BMD of the lumbar spine (∆ mean difference = 1.60%; 95% confidence interval − 1.44, 4.63; p = 0.30). The certainty for improvement was greater for muscle strength compared with BMD, evidenced by less heterogeneity (I2 = 78.1% vs 98.6%) and a higher overall quality of evidence. No training characteristic significantly affected both outcomes (p > 0.05), although concomitant increases in strength and BMD were favored by higher training frequencies, increases in strength were favored by resistance only and higher volumes, and increases in BMD were favored by combined resistance plus weight-bearing exercises, lower volumes, and higher loads. Conclusions: Progressive resistance training programs concomitantly increase lower-limb muscle strength and femur/hip bone mineral density in older adults, with greater certainty for strength improvement. Thus, to maximize the efficacy of progressive resistance training programs to concurrently prevent muscle and bone loss in older adults, it is recommended to incorporate training characteristics more likely to improve BMD. [ABSTRACT FROM AUTHOR]

Background: Weightlifting training (WLT) is commonly used to improve strength, power and speed in athletes. However, to date, WLT studies have either not compared training effects against those of other training methods, or been limited by small sample sizes, which are issues that can be resolved by pooling studies in a meta-analysis. Therefore, the objective of this systematic review with meta-analysis was to evaluate the effects of WLT compared with traditional resistance training (TRT), plyometric training (PLYO) and/or control (CON) on strength, power and speed. Methods: The systematic review included peer-reviewed articles that employed a WLT intervention, a comparison group (i.e. TRT, PLYO, CON), and a measure of strength, power and/or speed. Means and standard deviations of outcomes were converted to Hedges' g effect sizes using an inverse variance random-effects model to generate a weighted mean effect size (ES). Results: Sixteen studies were included in the analysis, comprising 427 participants. Data indicated that when compared with TRT, WLT resulted in greater improvements in weightlifting load lifted (4 studies, p = 0.02, g = 1.35; 95% CI 0.20–2.51) and countermovement jump (CMJ) height (9 studies, p = 0.00, g = 0.95; 95% CI 0.04–1.87). There was also a large effect in terms of linear sprint speed (4 studies, p = 0.13, g = 1.04; 95% CI − 0.03 to 2.39) and change of direction speed (CODS) (2 studies, p = 0.36, g = 1.21; 95% CI − 1.41 to 3.83); however, this was not significant. Interpretation of these findings should acknowledge the high heterogeneity across the included studies and potential risk of bias. WLT and PLYO resulted in similar improvements in speed, power and strength as demonstrated by negligible to moderate, non-significant effects in favour of WLT for improvements in linear sprint speed (4 studies, p = 0.35, g = 0.20; 95% CI − 0.23 to 0.63), CODS (3 studies, p = 0.52, g = 0.17; 95% CI − 0.35 to 0.68), CMJ (6 studies, p = 0.09, g = 0.31; 95% CI − 0.05 to 0.67), squat jump performance (5 studies, p = 0.08, g = 0.34; 95% CI − 0.04 to 0.73) and strength (4 studies, p = 0.20, g = 0.69; 95% CI − 0.37 to 1.75). Conclusion: Overall, these findings support the notion that if the training goal is to improve strength, power and speed, supplementary weightlifting training may be advantageous for athletic development. Whilst WLT and PLYO may result in similar improvements, WLT can elicit additional benefits above that of TRT, resulting in greater improvements in weightlifting and jumping performance. [ABSTRACT FROM AUTHOR]

Background: In resistance training, periodization is often used in an attempt to promote development of strength and muscle hypertrophy. However, it remains unclear how resistance training variables are most effectively periodized to maximize gains in strength and muscle hypertrophy. Objective: The aims of this study were to examine the current body of literature to determine whether there is an effect of periodization of training volume and intensity on maximal strength and muscle hypertrophy, and, if so, to determine how these variables are more effectively periodized to promote increases in strength and muscle hypertrophy, when volume is equated between conditions from pre to post intervention. Methods: Systematic searches were conducted in PubMed, Scopus and SPORTDiscus databases. Data from the individual studies were extracted and coded. Meta-analyses using the inverse-variance random effects model were performed to compare 1-repetition maximum (1RM) and muscle hypertrophy outcomes in (a) non-periodized (NP) versus periodized training and (b) in linear periodization (LP) versus undulating periodization (UP). Subgroup analyses examining whether results were affected by training status were performed. Meta-analyses of other periodization model comparisons were not performed, due to a low number of studies. Results: Thirty-five studies met the inclusion criteria. Results of the meta-analyses comparing NP and periodized training demonstrated an overall effect on 1RM strength favoring periodized training (ES 0.31, 95% confidence interval (CI) [0.04, 0.57]; Z = 2.28, P = 0.02). In contrast, muscle hypertrophy did not differ between NP and periodized training (ES 0.13, 95% CI [–0.10, 0.36]; Z = 1.10, P = 0.27). Results of the meta-analyses comparing LP and UP indicated an overall effect on 1RM favoring UP (ES 0.31, 95% CI [0.02, 0.61]; Z = 2.06, P = 0.04). Subgroup analyses indicated an effect on 1RM favoring UP in trained participants (ES 0.61, 95% CI [0.00, 1.22]; Z = 1.97 (P = 0.05)), whereas changes in 1RM did not differ between LP and UP in untrained participants (ES 0.06, 95% CI [–0.20, 0.31]; Z = 0.43 (P = 0.67)). The meta-analyses showed that muscle hypertrophy did not differ between LP and UP (ES 0.05, 95% CI [–0.20, 0.29]; Z = 0.36 (P = 0.72)). Conclusion: The results suggest that when volume is equated between conditions, periodized resistance training has a greater effect on 1RM strength compared to NP resistance training. Also, UP resulted in greater increases in 1RM compared to LP. However, subgroup analyses revealed that this was only the case for trained and not previously untrained individuals, indicating that trained individuals benefit from daily or weekly undulations in volume and intensity, when the aim is maximal strength. Periodization of volume and intensity does not seem to affect muscle hypertrophy in volume-equated pre-post designs. Based on this, we propose that the effects of periodization on maximal strength may instead be related to the neurophysiological adaptations accompanying resistance training. [ABSTRACT FROM AUTHOR]

Background: Engaging in both resistance and endurance exercise within the same training program, termed 'concurrent exercise training,' is common practice in many athletic disciplines that require a combination of strength and endurance and is recommended by a number of organizations to improve muscular and cardiovascular health and reduce the risk of chronic metabolic disease. Dietary protein ingestion supports skeletal muscle remodeling after exercise by stimulating the synthesis of muscle proteins and can optimize resistance exercise-training mediated increases in skeletal muscle size and strength; however, the effects of protein supplementation on acute and longer-term adaptive responses to concurrent resistance and endurance exercise are unclear. Objectives: The purpose of this systematic review is to evaluate the effects of dietary protein supplementation on acute changes in muscle protein synthesis and longer-term changes in muscle mass, strength, and aerobic capacity in responses to concurrent resistance and endurance exercise in healthy adults. Methods: A systematic search was conducted in five databases: Scopus, Embase, Medline, PubMed, and Web of Science. Acute and longer-term controlled trials involving concurrent exercise and protein supplementation in healthy adults (ages 18–65 years) were included in this systematic review. Main outcomes of interest were changes in skeletal muscle protein synthesis rates, muscle mass, muscle strength, and whole-body aerobic capacity (i.e., maximal/peak aerobic capacity [VO2max/peak]). The quality of studies was assessed using the National Institute of Health Quality Assessment for Controlled Intervention Studies. Results: Four acute studies including 84 trained young males and ten longer-term studies including 167 trained and 391 untrained participants fulfilled the eligibility criteria. All included acute studies demonstrated that protein ingestion enhanced myofibrillar protein synthesis rates, but not mitochondrial protein synthesis rates during post-exercise recovery after an acute bout of concurrent exercise. Of the included longer-term training studies, five out of nine reported that protein supplementation enhanced concurrent training-mediated increases in muscle mass, while five out of nine studies reported that protein supplementation enhanced concurrent training-mediated increases in muscle strength and/or power. In terms of aerobic adaptations, all six included studies reported no effect of protein supplementation on concurrent training-mediated increases in VO2max/peak. Conclusion: Protein ingestion after an acute bout of concurrent exercise further increases myofibrillar, but not mitochondrial, protein synthesis rates during post-exercise recovery. There is some evidence that protein supplementation during longer-term training further enhances concurrent training-mediated increases in skeletal muscle mass and strength/power, but not whole-body aerobic capacity (i.e., VO2max/peak). [ABSTRACT FROM AUTHOR]

Resistance training (RT) is the only non-pharmacological intervention known to consistently improve, and therefore offset age-related declines in, skeletal muscle mass, strength, and power. RT is also associated with various health benefits that are underappreciated compared with the perceived benefits of aerobic-based exercise. For example, RT participation is associated with reduced all-cause and cancer-related mortality and reduced incidence of cardiovascular disease, hypertension, and symptoms of both anxiety and depression. Despite these benefits, participation in RT remains low, likely due to numerous factors including time constraints, a high-perceived difficulty, and limited access to facilities and equipment. Identification of RT strategies that limit barriers to participation may increase engagement in RT and subsequently improve population health outcomes. Across the lifespan, declines in strength and power occur up to eight times faster than the loss of muscle mass, and are more strongly associated with functional impairments and risks of morbidity and mortality. Strategies to maximise healthspan should therefore arguably focus more on improving or maintaining muscle strength and power than on increasing muscle mass per se. Accumulating evidence suggests that minimal doses of RT, characterised by lower session volumes than in traditional RT guidelines, together with either (1) higher training intensities/loads performed at lower frequencies (i.e. low-volume, high-load RT) or (2) lower training intensities/loads performed at higher frequencies and with minimal-to-no equipment (i.e. resistance 'exercise snacking'), can improve strength and functional ability in younger and older adults. Such minimal-dose approaches to RT have the potential to minimise various barriers to participation, and may have positive implications for the feasibility and scalability of RT. In addition, brief but frequent minimal-dose RT approaches (i.e. resistance 'exercise snacking') may provide additional benefits for interrupting sedentary behaviour patterns associated with increased cardiometabolic risk. Compared to traditional approaches, minimal-dose RT may also limit negative affective responses, such as increased discomfort and lowered enjoyment, both of which are associated with higher training volumes and may negatively influence exercise adherence. A number of practical factors, including the selection of exercises that target major muscle groups and challenge both balance and the stabilising musculature, may influence the effectiveness of minimal-dose RT on outcomes such as improved independence and quality-of-life in older adults. This narrative review aims to summarise the evidence for minimal-dose RT as a strategy for preserving muscle strength and functional ability across the lifespan, and to discuss practical models and considerations for the application of minimal-dose RT approaches. [ABSTRACT FROM AUTHOR]

Background: Higher neck strength has been postulated to reduce head impact magnitude during purposeful heading in football. Objectives: This pilot trial explored the effect of a neck exercise programme on (1) neck strength and (2) head impact magnitude during heading in male and female adolescent football players. Methods: Boys and girls (aged 12–17 years) were randomised by team to the intervention (5 weeks of supervised neuromuscular neck exercises integrated into part 2 of the FIFA 11 + , completed three times per week) or the control group (usual part 2 of the FIFA 11 + , no neck exercises). Outcomes included isometric neck strength and head impact magnitude (peak linear acceleration and peak angular velocity) during standardised heading from a throw-in (at baseline and 6 weeks) plus completion of an evaluation survey by intervention players and coaches. Results: In total, 52 players (n = 31 intervention; n = 21 control) completed the study. Mixed-model analysis of variance (ANOVA) revealed significant differences in neck strength variables (p < 0.001), peak linear acceleration (p = 0.04) and peak angular velocity (p = 0.04) between the intervention and control groups over time. Intervention players demonstrated increases in mean composite neck strength (53.8% intervention vs 15.6% control) as well as decreases in mean peak linear head acceleration during heading (− 11.8% vs − 5.0%) from baseline to follow-up. Reduction in peak angular velocity was more pronounced in girls (− 27.7%) than boys (− 11.5%) in the intervention group. The addition of neck exercises into part 2 of the FIFA 11 + was feasible and accepted by players and coaches. Conclusion: On average, players who completed neck exercises demonstrated an increase in isometric neck strength and a decrease in head impact magnitude during heading. These exercises were easily incorporated into usual training. Australian New Zealand Clinical Trials Registry (no: ACTRN12619001375145). [ABSTRACT FROM AUTHOR]

Background: Resistance training is the gold standard exercise mode for accrual of lean muscle mass, but the isolated effect of resistance training on body fat is unknown. Objectives: This systematic review and meta-analysis evaluated resistance training for body composition outcomes in healthy adults. Our primary outcome was body fat percentage; secondary outcomes were body fat mass and visceral fat. Design: Systematic review with meta-analysis. Data Sources: We searched five electronic databases up to January 2021. Eligibility Criteria: We included randomised trials that compared full-body resistance training for at least 4 weeks to no-exercise control in healthy adults. Analysis: We assessed study quality with the TESTEX tool and conducted a random-effects meta-analysis, with a subgroup analysis based on measurement type (scan or non-scan) and sex (male or female), and a meta-regression for volume of resistance training and training components. Results: From 11,981 records, we included 58 studies in the review, with 54 providing data for a meta-analysis. Mean study quality was 9/15 (range 6–15). Compared to the control, resistance training reduced body fat percentage by − 1.46% (95% confidence interval − 1.78 to − 1.14, p < 0.0001), body fat mass by − 0.55 kg (95% confidence interval − 0.75 to − 0.34, p < 0.0001) and visceral fat by a standardised mean difference of − 0.49 (95% confidence interval − 0.87 to − 0.11, p = 0.0114). Measurement type was a significant moderator in body fat percentage and body fat mass, but sex was not. Training volume and training components were not associated with effect size. Summary/Conclusions: Resistance training reduces body fat percentage, body fat mass and visceral fat in healthy adults. Study Registration: osf.io/hsk32. [ABSTRACT FROM AUTHOR]

It has been suggested that improper post-exercise recovery or improper sequence of training may result in an 'accumulation' of fatigue. Despite this suggestion, there is a lack of clarity regarding which physiological mechanisms may be proposed to contribute to fatigue accumulation. The present paper explores the time course of the changes in various fatigue-related measures in order to understand how they may accumulate or lessen over time following an exercise bout or in the context of an exercise program. Regarding peripheral fatigue, the depletion of energy substrates and accumulation of metabolic byproducts has been demonstrated to occur following an acute bout of resistance training; however, peripheral accumulation and depletion appear unlikely candidates to accumulate over time. A number of mechanisms may contribute to the development of central fatigue, postulating the need for prolonged periods of recovery; however, a time course is difficult to determine and is dependent on which measurement is examined. In addition, it has not been demonstrated that central fatigue measures accumulate over time. A potential candidate that may be interpreted as accumulated fatigue is muscle damage, which shares similar characteristics (i.e., prolonged strength loss). Due to the delayed appearance of muscle damage, it may be interpreted as accumulated fatigue. Overall, evidence for the presence of fatigue accumulation with resistance training is equivocal, making it difficult to draw the conclusion that fatigue accumulates. Considerable work remains as to whether fatigue can accumulate over time. Future studies are warranted to elucidate potential mechanisms underlying the concept of fatigue accumulation. [ABSTRACT FROM AUTHOR]

Resistance exercise is used extensively in athletic and general populations to induce neuromuscular adaptations to increase muscle size and performance. Exercise parameters such as exercise frequency, intensity, duration and modality are carefully manipulated to induce specific adaptations to the neuromuscular system. While the benefits of resistance exercise on the neuromuscular system are well documented, there is growing evidence to suggest that resistance exercise, even when performed acutely, can lead to neuroplastic changes within the central nervous system (CNS) and improve cognitive functioning. As such, resistance exercise has been proposed as a novel adjuvant rehabilitation strategy in populations that suffer from neurological or neurocognitive impairments (i.e. Parkinson's and Alzheimer's dementia) or even to attenuate age-related declines in cognitive health. In this review, we present evidence for the neuroplastic effects and cognitive benefits of resistance exercise and propose some of the underlying mechanisms that drive neuroplasticity following resistance training. We will further discuss the effects of exercise parameters, in particular exercise frequency, intensity, duration and modality to improve cognitive health. Lastly, we will highlight some of the existing limitations in the literature surrounding the use of resistance exercise to improve cognitive function and propose considerations to improve future studies in this field. In summary, the current evidence supports the role of resistance exercise, as a stand alone or in combination with aerobic exercise, for benefiting cognitive health and that it should be considered as an adjuvant therapy to treat age- or disease-related cognitive declines. [ABSTRACT FROM AUTHOR]

Background: Changes in body composition during cancer treatments have been linked with poorer outcomes, and increased morbidity and mortality. The effect of resistance training (RT) on body composition in cancer cohorts is debated. Objective: We conducted a systematic review and meta-analysis to determine the effect of RT on body composition during and after treatment. Methods: We searched five electronic databases for articles up to 1 February 2021 and included randomized controlled trials that compared RT with a non-exercise control in adults with cancer. Risk of bias was assessed using the RoB 2 tool. Pairwise, random-effects meta-analysis was used to synthesize the available data. Results: Overall, we included 15 studies (n = 1368). After treatment (11 studies), RT increased lean mass with moderate heterogeneity {0.41 kg [95% confidence interval (CI) 0.05, 0.76], p = 0.029; I2 = 47.1%, p = 0.02} and decreased fat mass with substantial heterogeneity (− 0.59 kg [95% CI − 1.05, − 0.12], p = 0.019; I2 = 69.1%, p < 0.001). During treatment (4 studies), RT did not increase lean mass (0.71 kg [95% CI − 0.04, 1.45], p = 0.05; I2 = 0.0%, p = 0.75) or reduce fat mass (0.00 kg [95% CI − 5.31, 5.30], p = 0.99; I2 = 0.0%, p = 0.62), both with no heterogeneity. Conclusion: Modest improvements in body composition were observed following RT after cancer treatment; however, no changes were observed during treatment. These adaptations are markedly lower than those observed in healthy cohorts but may be clinically meaningful for the cancer survivorship population. At present it is unclear if these diminished adaptations are due to ineffective exercise prescriptions in cancer cohorts or due to an innate anabolic resistance as a result of cancer and its treatments. Study registration: Open Science Framework (osf.io/x6z72). [ABSTRACT FROM AUTHOR]

Due to improvements in acute burn care over the last few decades, most patients with severe burns (up to 90% of the total body surface) survive. However, the metabolic and cardiovascular complications that accompany a severe burn can persist for up to 3 years post injury. Accordingly, there is now a greater appreciation of the need for strategies that can hasten recovery and reduce long-term morbidity post burn. Rehabilitation exercise training (RET) is a proven effective treatment to restore lean body mass, glucose and protein metabolism, cardiorespiratory fitness, and muscle strength in burn survivors. Despite this, very few hospitals incorporate RET in programs to aid the rehabilitation of patients with severe burns. Given that RET is a safe and efficacious treatment that restores function and reduces post-burn morbidity, we propose that a long-term exercise prescription plan should be considered for all patients with severe burns. In this literature review, we discuss the current understanding of burn trauma on major organ systems, and the positive benefits of incorporating RET as a part of the long-term rehabilitation of severely burned individuals. We also provide burn-specific exercise prescription guidelines for clinical exercise physiologists. [ABSTRACT FROM AUTHOR]

It is established that protein requirements are elevated in athletes to support their training and post-exercise recovery and adaptation, especially within skeletal muscle. However, research on the requirements for this macronutrient has been performed almost exclusively in younger athletes, which may complicate their translation to the growing population of Master athletes (i.e. > 35 years old). In contrast to older (> 65 years) untrained adults who typically demonstrate anabolic resistance to dietary protein as a primary mediator of the 'normal' age-related loss of muscle mass and strength, Master athletes are generally considered successful models of aging as evidenced by possessing similar body composition, muscle mass, and aerobic fitness as untrained adults more than half their age. The primary physiology changes considered to underpin the anabolic resistance of aging are precipitated or exacerbated by physical inactivity, which has led to higher protein recommendations to stimulate muscle protein synthesis in older untrained compared to younger untrained adults. This review puts forth the argument that Master athletes have similar muscle characteristics, physiological responses to exercise, and protein metabolism as young athletes and, therefore, are unlikely to have protein requirements that are different from their young contemporaries. Recommendations for protein amount, type, and pattern will be discussed for Master athletes to enhance their recovery from and adaptation to resistance and endurance training. [ABSTRACT FROM AUTHOR]

Background: In-season competition and tournaments for team sports can be both long and congested, with some sports competing up to three times per week. During these periods of time, athletes need to prepare technically, tactically and physically for the next fixture and the short duration between fixtures means that, in some cases, physical preparation ceases, or training focus moves to recovery as opposed to progressing adaptations. Objective: The aim of this review was to investigate the effect of training frequency on muscular strength to determine if a potential method to accommodate in-season resistance training, during busy training schedules, could be achieved by utilizing shorter more frequent training sessions across a training week. Methods: A literature search was conducted using the SPORTDiscus, Ovid, PubMed and Scopus databases. 2134 studies were identified prior to application of the following inclusion criteria: (1) maximal strength was assessed, (2) a minimum of two different training frequency groups were included, (3) participants were well trained, and finally (4) compound exercises were included within the training programmes. A Cochrane risk of bias assessment was applied to studies that performed randomized controlled trials and consistency of studies was analysed using I2 as a test of heterogeneity. Secondary analysis of studies included Hedges' g effect sizes (g) and between-study differences were estimated using a random-effects model. Results: Inconsistency of effects between pre- and post-intervention was low within-group (I2 = 0%), and moderate between-group (I2 ≤ 73.95%). Risk of bias was also low based upon the Cochrane risk of bias assessment. Significant increases were observed overall for both upper (p ≤ 0.022) and lower (p ≤ 0.008) body strength, pre- to post-intervention, when all frequencies were assessed. A small effect was observed between training frequencies for upper (g ≤ 0.58) and lower body (g ≤ 0.45). Conclusion: Over a 6–12-week period, there are no clear differences in maximal strength development between training frequencies, in well-trained populations. Such observations may permit the potential for training to be manipulated around competition schedules and volume to be distributed across shorter, but more frequent training sessions within a micro-cycle rather than being condensed into 1–2 sessions per week, in effect, allowing for a micro-dosing of the strength stimuli. [ABSTRACT FROM AUTHOR]

Objective: To investigate the role of muscle thickness changes on changes in strength following 6 weeks of unaccustomed resistance training, via retrospective analysis. Methods: 151 participants completed 6 weeks of no intervention (CONTROL), one-repetition maximum training (1RM-TRAIN), or traditional resistance training (TRAD-TRAIN). Groups were assigned by covariate adaptive randomization. 1RM-TRAIN and TRAD-TRAIN performed elbow flexion exercise on the dominant arm 3 times/week. One-repetition maximum strength and muscle thickness (B-mode ultrasound at 50, 60, and 70% of the anterior upper arm) were assessed pre- and post-training. Direct and indirect effects on strength via each training modality were quantified relative to CONTROL using indicator-coded, change-score mediation analyses for each muscle thickness site. Values are presented as regression coefficients (95% CI). Results: The effect of 1RM-TRAIN on muscle thickness was greater than CONTROL for 60% [0.09 (0.01, 0.17) cm] and 70% [0.09 (0.01,0.18) cm] models. All muscle thickness changes for TRAD-TRAIN were greater than CONTROL: 50% [0.24 (0.16, 0.33) cm], 60% [0.25 (0.17, 0.33) cm], 70% [0.23 (0.14, 0.32) cm]. All direct effects on strength were greater for 1RM-TRAIN versus CONTROL: 50% [1.90 (1.21, 2.58) kg], 60% [1.89 (1.19, 2.58) kg], 70% [1.81 (1.12, 2.51) kg]; and TRAD-TRAIN versus CONTROL: 50% [2.04 (1.29, 2.80) kg], 60% [1.98 (1.22, 2.75) kg], 70% [1.79 (1.05, 2.53) kg]. Compared to CONTROL, there was no indication of an effect of 1RM-TRAIN on strength through muscle thickness (i.e., indirect effect) for 50% [− 0.03 (− 0.17, 0.10)], 60% [− 0.01 (− 0.17, 0.17)], or 70% [0.07 (− 0.09, 0.28)] sites, nor of TRAD-TRAIN for 50% [− 0.11 (− 0.48,0.29)], 60% [− 0.04 (− 0.42, 0.40)], and 70% sites [0.17 (− 0.23,0.58)]. Conclusion: Training-induced changes in muscle thickness do not appear to appreciably mediate training-induced changes in the strength of untrained individuals during the first 6 weeks of training. [ABSTRACT FROM AUTHOR]

Background: Despite the intriguing potential of physical exercise being able to preserve or even restore brain volume (grey matter volume in particular)—a tissue essential for both cognitive and physical function—no reviews have so far synthesized the existing knowledge from randomized controlled trials investigating exercise-induced changes of the brain's grey matter volume in populations at risk of neurodegeneration. Our objective was to critically review the existing evidence regarding this topic. Methods: A systematic search was carried out in MEDLINE and EMBASE databases primo April 2020, to identify randomized controlled trials evaluating the effects of aerobic training, resistance training or concurrent training on brain grey volume changes (by MRI) in adult clinical or healthy elderly populations. Results: A total of 20 articles (from 19 RCTs) evaluating 3–12 months of aerobic, resistance, or concurrent training were identified and included, involving a total of 1662 participants (populations: healthy older adults, older adults with mild cognitive impairment or Alzheimer's disease, adults with schizophrenia or multiple sclerosis or major depression). While few studies indicated a positive effect—although modest—of physical exercise on certain regions of brain grey matter volume, the majority of study findings were neutral (i.e., no effects/small effect sizes) and quite divergent across populations. Meta-analyses showed that different exercise modalities failed to elicit any substantial effects on whole brain grey volume and hippocampus volume, although with rather large confidence interval width (i.e., variability). Conclusion: Altogether, the current evidence on the effects of physical exercise on whole/regional grey matter brain volume appear sparse and inconclusive, and does not support that physical exercise is as potent as previously proposed when it comes to affecting brain grey matter volume. [ABSTRACT FROM AUTHOR]

In the article, the author discusses the benefits of resistance exercise in cancer survivorship. Topics include the systematic review and meta-analysis of the effect of resistance training on body composition during cancer treatment, the recommendations by the American College of Sports Medicine in promoting muscle hypertrophy, and the protein metabolism data among survivors of colorectal cancer.