Hormonal responses and adaptations to resistance exercise and training

The role of resistance exercise-induced local metabolic stress in mediating systemic health and functional adaptations: could condensed training volume unlock greater benefits beyond time efficiency?

The majority of "specialised" exercise configurations (e.g., supersets, drop sets, blood flow restriction) are being assessed as "shortcuts" to hypertrophy and strength improvements. However, these advanced training techniques may also offer significant benefits for systemic health and functional outcomes across recreational and clinical populations via locally induced metabolic responses. Stress-regulating mechanisms are known to enhance the body's resilience by facilitating allostasis, the process of coordinating adaptive processes in reaction to stressors such as physical training. Yet, the role of the local metabolic stress provoked by resistance exercise has not gained much research attention despite its wide potential. Positive effects are not only linked to improved muscular endurance, hypertrophy and strength via primary and secondary mechanisms, but also to the release of myokines, hormones, microRNAs, immune factors, inflammatory substances and other endocrine molecules that initiate numerous health-promoting modifications on a systemic level. Resistance exercise strategies that maximise the local accumulation of metabolites are not well defined, although high volume, close proximity to failure and shorter rests seem to be a necessity. Additionally, blood flow restriction training provides a potent alternative for inducing local acidosis, thereby triggering several pathways associated with improved immunity and physical function even in remote muscle tissues. Future research is warranted to further explore advanced resistance training techniques, as these approaches may offer comparable benefits for physical and mental health to those seen with other forms of exercise such as high-intensity interval training and heavy resistance training.

Effect of Metabolic Stress to High-Load Exercise on Muscle Damage, Inflammatory and Hormonal Responses

To assess the impact of metabolic stress on blood lactate, muscle damage, inflammatory and hormonal responses following a high-load (70% maximum) strength training session, we compared two methods with a similar number of repetitions but that differed by their metabolic demand: the 3/7 method consisting in two series of five sets of an increasing number of repetitions (3 to 7) with a short inter-set interval (15 s) and the 8 × 6 method that comprises eight sets of six repetitions with a longer inter-set interval (2.5 min). Blood concentrations in lactate, creatine kinase (CK), myoglobin (MB), interleukine-6 (IL-6), leukocytes, growth hormone (GH), insulin-like growth factor-1 (IGF-1) and cortisol were determined before and after each session. Lactate concentration increased more (11.9 vs. 3.1 mmol/L; p < 0.001) for the 3/7 method whereas CK and MB concentrations were augmented similarly (p > 0.05) for both methods. Inflammatory markers (leukocytes and IL-6) increased (p < 0.01) more after the 3/7 method. GH and cortisol concentrations also increased more (p < 0.001) after the 3/7 method with no difference in IGF-1 concentrations between methods. Positive associations were found between the change in lactate and changes in IL-6 (r2 = 0.47; p < 0.01), GH (r2 = 0.58; p < 0.001) and cortisol (r2 = 0.61; p < 0.001) concentrations. In conclusion, the greater lactate accumulation induced by short inter-set intervals during a high-load training session is associated with enhanced inflammatory and hormonal responses, suggesting that metabolic stress might contribute to the greater adaptative response previously observed with this method.

Southeast Asian, African, and Middle East Expert Consensus on Structured Physical Activity-Dance, Exercise, and Sports

Physical inactivity (PIA) is a pressing public health issue globally, contributing significantly to the rise of non-communicable diseases (NCD), such as cardiovascular disease and type 2 diabetes. The World Health Organization emphasises the importance of regular physical activity (PA) for preventing and managing NCDs. Initiatives to promote active living have gained momentum, ranging from community programs to workplace wellness campaigns, all focused on reducing sedentary lifestyles in modern society. Structured Physical Activity-Dance, Exercise, and Sports (SPADES) has emerged as an innovative approach to addressing PIA and promoting holistic health. After thoroughly reviewing existing literature from PubMed and Google Scholar databases, a panel of experts developed consensus statements through in-depth discussions, and the strength of concurrence on these statements was voted on using a Likert scale. The panel reached a consensus on the best strategies for PA, dance, exercise, sports, and key factors to consider during PA. This consensus targets individuals with metabolic diseases, particularly in regions like South Asia, East Africa, the Gulf, and Latin America, where these conditions are highly prevalent. The SPADES guidelines emphasise overcoming the barriers people with metabolic disorders face in achieving adequate PA, providing tailored recommendations to improve health outcomes for this population.

Effects of Ladder-Climbing Exercise on Mammary Cancer: Data from a Chemically Induced Rat Model

Breast cancer remains a significant global health issue, affecting both humans and companion animals, particularly female dogs and cats, where mammary tumors are among the most common cancers. Strategies to minimize the impact of this disease on patients, pet owners, and veterinary medicine are essential. This study analyses the effects of resistance training on the development of chemically induced mammary cancer in female Wistar rats, divided into four groups: sedentary control (CTR), sedentary induced (CTR+N-methyl-N-nitrosourea (MNU)), exercised control (EX), and exercised induced (EX+MNU). The exercise protocol involved ladder climbing three times a week for 18 weeks with the load progressively increasing. At the study's end, blood and histopathological samples were collected and analyzed. Although tumor onset occurred two weeks earlier and incidence was slightly higher in the exercised group (EX+MNU) compared to the control group (CTR+MNU), the mortality rate was lower, and the malignancy was not as aggressive. No systemic inflammation was observed, as the levels of albumin, C-reactive protein (CRP), and interleukin 6 (IL-6) in the MNU groups remained similar to the controls. Exercise has been shown to promote overall health by increasing physical fitness, boosting immunological function, and improving metabolic health. These findings may offer valuable insights into the potential role of resistance training in managing mammary cancer in companion animals. However, further research is required to assess clinical applicability and to establish safe and effective exercise protocols for veterinary oncology.

Multimodal Adaptations to Expiratory Musculature-Targeted Resistance Training: A Preliminary Study in Healthy Young Adults

PURPOSE

Exercise-induced adaptations, including neuroplasticity, are well studied for physical exercise that targets skeletal muscles. However, little is known about the neuroplastic potential of targeted speech and swallowing exercises. The current study aimed to gather preliminary data on molecular and functional changes associated with the neuroplastic effects of 4-week expiratory musculature-targeted resistance training in healthy young adults.

METHOD

Five healthy young adult men aged between 19 and 35 years, M (SD) = 28.8 (2.68) years, underwent 4 weeks of expiratory muscle strength training (EMST). We measured changes in maximum expiratory pressure (MEP), serum brain-derived neurotrophic factor (BDNF), and insulin-like growth factor 1 (IGF-1) levels at baseline and posttraining conditions. Furthermore, functional and structural magnetic resonance images were obtained to investigate the neuroplastic effects of EMST. We analyzed the effects of training using a linear mixed model for each outcome, with fixed effects for baseline and posttraining.

RESULTS

MEP and serum BDNF levels significantly increased posttraining. However, this effect was not observed for IGF-1. A significant increase in functional activation in eight regions was also observed posttraining. However, we did not observe significant changes in the white matter microstructure.

CONCLUSIONS

Preliminary data from our study suggest targeted resistance training of expiratory muscles results in molecular and neuroplastic adaptations similar to exercise that targets skeletal muscles. Additionally, these results suggest that EMST could be a potential intervention to modulate (or prime) neurotrophic signaling pathways linked to functional strength gains and neuroplasticity.

Effectiveness of exercise interventions on sperm quality: a systematic review and network meta-analysis

Background

Infertility affects about 10% to 15% of the world's population, thus making it a global concern. Although there are a large number of studies to develop treatment for infertility in men, there are no studies to illustrate the effect of exercise on male sperm treatment in a well rationalized and aggregated manner, therefore the aim of this study was to validate the comparative effectiveness of different exercise interventions for treating sperm quality in men by using a network Meta-analysis.

Methods

All randomized clinical trials (RCT) were obtained from PubMed, Cochrane Library, EMBASE, Web of Science, CNKI, Wanfang, and VIP databases, and network meta-analysis was used to assess the effectiveness of exercise interventions on sperm quality.

Results

Fourteen studies with 1079 subjects were finally included in this study. Compared with the physical inactivity group, indoor aerobic, outdoor aerobic, and resistance training significantly reduced sperm density (P<0.05); indoor aerobic, outdoor aerobic, and resistance training significantly reduced the number of necrotic spermatozoa and the number of active spermatozoa (P>0.05).Outdoor aerobic[MD=1.84,95%CI:(1.56,2.14),P<0.05], multi-component motion [MD=1.37,95%CI:(0.85,1.89),P<0.05],competitive sports[MD=1.04,95%CI:(0.46,1.60),P<0.05],indoor aerobic [MD=0.32, 95%CI:(0.21,0.44), P<0.05], effectively enhanced sperm volume; other sports [MD=9.49,95%CI:(6.17,12.84),P<0.05], indoor aerobic[MD=4.43,95%CI:(3.12,5.74),P<0.05],resistance training [MD=3.93, 95%CI:(0.49,7.37), P<0.05], competitive sports [MD=5.44,95%CI:(0.10,10.79), P<0.05], and bicycle aerobics[MD=27.29,95%CI:(22.45,32.06),P<0.05], significantly enhanced sperm motility; other sports [MD=17.20,95%CI:(3.12,31.19), P<0.05], effectively enhanced total sperm count;resistance training[MD=10.90,95%CI:(8.44,13.36), P<0.05],other sports [MD=1.97,95%CI:(1.41,2.54),P<0.05], indoor aerobic [MD=2.43,95%CI:(1.13,3.73), P<0.05],and bicycle aerobic [MD=12.18, 95%CI:(10.19,14.18),P<0.05], significantly enhanced sperm morphology; bicycle aerobic (MD=18.87, 95%CI:11.70,25.86, P<0.05), and indoor aerobic (MD=9.53, 95%CI:8.97,10.09, P<0.05),effectively enhanced sperm concentration.

Conclusion

In conclusion, outdoor aerobics had a significant effect on improving sperm volume in infertile patients; other sports had a significant effect on enhancing sperm motility and total sperm count in infertile patients; resistance training had a significant effect on enhancing sperm morphology in infertile patients, and bicycle aerobic has a significant impact on improving sperm concentration in infertile patients.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#myprospero, identifier CRD42024534582.

Charting the Molecular Terrain of Exercise: Energetics, Exerkines, and the Future of Multiomic Mapping

Physical activity plays a fundamental role in human health and disease. Exercise has been shown to improve a wide variety of disease states, and the scientific community is committed to understanding the precise molecular mechanisms that underlie the exquisite benefits. This review provides an overview of molecular responses to acute exercise and chronic training, particularly energy mobilization and generation, structural adaptation, inflammation, and immune regulation. Furthermore, it offers a detailed discussion of known molecular signals and systemic regulators activated during various forms of exercise and their role in orchestrating health benefits. Critically, the increasing use of multiomic technologies is explored with an emphasis on how multiomic and multitissue studies contribute to a more profound understanding of exercise biology. These data inform anticipated future advancement in the field and highlight the prospect of integrating exercise with pharmacology for personalized disease prevention and treatment.

What are the potential mechanisms of fatigue-induced skeletal muscle hypertrophy with low-load resistance exercise training?

High-load resistance exercise (>60% of 1-repetition maximum) is a well-known stimulus to enhance skeletal muscle hypertrophy with chronic training. However, studies have intriguingly shown that low-load resistance exercise training (RET) (≤60% of 1-repetition maximum) can lead to similar increases in skeletal muscle hypertrophy as compared with high-load RET. This has raised questions about the underlying mechanisms for eliciting the hypertrophic response with low-load RET. A key characteristic of low-load RET is performing resistance exercise to, or close to, task failure, thereby inducing muscle fatigue. The primary aim of this evidence-based narrative review is to explore whether muscle fatigue may act as an indirect or direct mechanism contributing to skeletal muscle hypertrophy during low-load RET. It has been proposed that muscle fatigue could indirectly stimulate muscle hypertrophy through increased muscle fiber recruitment, mechanical tension, ultrastructural muscle damage, the secretion of anabolic hormones, and/or alterations in the expression of specific proteins involved in muscle mass regulation (e.g., myostatin). Alternatively, it has been proposed that fatigue could directly stimulate muscle hypertrophy through the accumulation of metabolic by-products (e.g., lactate), and/or inflammation and oxidative stress. This review summarizes the existing literature eluding to the role of muscle fatigue as a stimulus for low-load RET-induced muscle hypertrophy and provides suggested avenues for future research to elucidate how muscle fatigue could mediate skeletal muscle hypertrophy.

Anserine, Balenine, and Ergothioneine: Impact of Histidine-Containing Compounds on Exercise Performance-A Narrative Review

Histidine is an amino acid which plays a critical role in protein synthesis, muscle buffering during anaerobic exercise, and antioxidation. It also acts as a precursor to carnosine, a dipeptide that enhances physical performance by being present in fast-contracting muscle fibers and contributing to buffering capacity. Recent studies have examined other histidine-containing compounds, such as anserine, balenine, and ergothioneine, to assess their potential benefits for physical activity. This narrative review focuses on the literature about the effects of dietary supplementation with these histidine-containing compounds on exercise capacity in animals and humans. The findings indicate that anserine may improve physical performance and reduce fatigue, particularly in quick, repetitive activities. Although balenine has been less extensively studied, it has shown promise in enhancing muscle regeneration and antioxidative defense in animal models. Ergothioneine, a sulfur-containing histidine derivative, displayed antioxidant and anti-inflammatory properties in both animal and human studies, suggesting its potential role in reducing exercise-induced oxidative stress and aiding recovery. The diversity of the presented studies and their limitations do not provide an opportunity to confirm the ergogenic properties of the histidine-containing compounds studied. Nevertheless, supplementation with anserine and ergothioneine shows promise for enhancing physical performance and recovery, though further research is required to better understand their mechanisms and optimize their use in sports and exercise.

The Comparative Effects of High-Intensity Interval Training and Traditional Resistance Training on Hormonal Responses in Young Women: A 10-Week Intervention Study

BACKGROUND

Hormonal levels in women are influenced by exercise intensity and modality.

METHODS

This 10-week study compared high-intensity interval training (HIIT) and traditional resistance training (TRT) in 72 young women. Hormonal levels (estrogen, testosterone, FSH, prolactin, and LH) were measured pre- and post-intervention.

RESULTS

Both groups showed significant increases in estrogen (HIIT: 150%; TRT: 72.3%) and decreases in testosterone (HIIT: 58%; TRT: 49%), FSH (HIIT: 6%; TRT: 7.7%), and PL (HIIT: 5%; TRT: 2.1%). There are no significant changes in LH.

CONCLUSIONS

HIIT and TRT effectively modulate hormonal profiles, potentially benefiting reproductive and metabolic health.

The physiological responses to volume-matched high-intensity functional training protocols with varied time domains

Background

High-intensity functional training (HIFT) is typically performed with minimal or no rest periods, including "rounds for time" (RFT) or "as many rounds or repetitions as possible" (AMRAP) design. Alternatively, some HIFT workouts can be performed with prescribed rest intervals (e.g., "every minute on the minute" [EMOM]) that may have significant effects on physiological responses.

Purpose

To compare the physiological responses between two different HIFT workouts (EMOM and RFT) that were matched for total work volume (TWV).

Methods

Twelve trained individuals (six males and six females) performed two HIFT protocols, EMOM and RFT. Both the EMOM and RFT included five rounds of five power cleans, eight kipping pull-ups, six dumbbell thrusters, and ten burpees performed in this order. Measurements of heart rate (HR), oxygen consumption (VO2), rating of perceived exertion (RPE) (1-10 scale), blood lactate (BLA), creatine kinase (CK), excess post-exercise oxygen consumption (EPOC), and muscle oxygen saturation (SmO2) were performed.

Results

Time domains were significantly different for the EMOM and RFT workouts (20 vs. 12 min ± 3 min, p < 0.00). There were significant differences between the EMOM and RFT for HR (153 ± 19 bpm vs. 171 ± 12 bpm, p < 0.01), VO2 (30.8 ± 3 mL/kg/min vs. 38.1 ± 5 mL/kg/min, p < 0.00), RPE (4 ± 1 vs. 7 ± 1, p < 0.00), and EPOC-AUC (3.5 ± 1.2 mL/kg/min vs. 5.0 ± 1.3 mL/kg/min, p < 0.00); however, there were no significant differences in mean SmO2 (p = 0.44). An interaction effect revealed that BLA was lower for the EMOM (6.5 ± 2.7 mmol/L) than the RFT (11.2 ± 2.1 mmol/L) post-exercise (p < 0.00). Conversely, there was no interaction effect for CK (p < 0.16), yet a significant increase was observed from pre- to post-exercise for both the EMOM and the RFT (p < 0.01).

Conclusion

The RFT induced greater physiological stress than the EMOM, indicating that prescribed rest intervals significantly affect the metabolic, cardiovascular, and perceptual responses during high-intensity functional exercise. Furthermore, the RFT may provide a greater cardiorespiratory stimulus, while the EMOM may be more suitable for technique development and recovery in trained individuals.

Hormonal and inflammatory responses in prepubertal vs. pubertal male children following an acute free-weight resistance training session

PURPOSE

Examine the acute hormonal and cytokine responses to free-weight resistance training in trained prepubertal and pubertal male children.

METHODS

Prepubertal (n = 21; age 11.4 ± 1.1 years; Tanner I-II) and pubertal male children (n = 20; age 15.8 ± 0.7 years; Tanner III-V) conducted a moderate-intensity free-weight resistance training program to failure with venous blood sampling before (pre), immediately after (post) and during the recovery phase of the program (post-15,-30 min). Growth hormone (GH), insulin-like growth factor-I (IGF-I), cortisol, testosterone, IL-6, and TNF-α were analyzed in serum samples. Biological maturation was assessed according to the stages of the Tanner scale.

RESULTS

There was a significant time-by-group interaction in IGF-I response (p = 0.044; η2 = 0.209) and testosterone (p < 0.001; η2 = 0.508), indicating a greater change in the pubertal group compared to the prepubertal group. Both groups significantly increased post-exercise GH levels (p < 0.05). Only the prepuberal group significantly increased levels of IL-6 at all post-exercise time points (p < 0.05). Both groups showed a significant (p < 0.05) increase in TNF-α levels compared to resting levels.

CONCLUSION

These data suggest that acute testosterone and IGF-I response following resistance training differ between trained prepubertal and pubertal male children. Moderate-intensity resistance training performed to failure may thus have different effects in trained prepubertal and pubertal male children, which should be considered when giving training advice.

TRIAL REGISTRATION

Clinical trials number: NCT05022992.

The neural correlates of physical exercise-induced general cognitive gains: A systematic review and meta-analysis of functional magnetic resonance imaging studies

The general-domain effect of physical exercise-induced cognitive gains in behavioral outcomes is well-documented, but a consensus on the neural correlates remains elusive. This meta-analysis aims to identify the neural correlates of physical exercise-induced general cognitive gains by examining task-related brain activation consistently modulated by physical exercise and its relationship to those gains. Our analysis of 52 studies with 1503 participants shows that physical exercise enhances cognitive task performance (Hedges' g = 0.271) and consistently increases task-related brain activation primarily in the bilateral precuneus. These increases in task-related brain activation correlate positively with cognitive task performance improvements improvements. Notably, physical exercise intensity, adherence, and social environment significantly modulate task-related brain activation changes induced by physical exercise. This meta-analysis offers an unprecedented comprehensive assessment of how physical exercise modulates task-related brain activation changes, providing neural evidence to support the general-domain effects on cognitive function induced by physical exercise.

Associations between subjective and objective measures of stress and load: an insight from 45-week prospective study in 189 elite athletes

Introduction

The aim of this study was to investigate the associations between subjective and objective measures of stress and load in elite male handball players at both the group and individual levels.

Methods

In this 45-week prospective cohort study, 189 elite male handball players weekly reported their perceived stress and load across training, competition, academic, and work domains. Blood samples were collected five times during the 2022/23 season to measure cortisol and the free testosterone to cortisol ratio (FTCR). We derived a "load" variable as the sum of training, competition, academic and work hours and calculated acute, chronic, and acute-to-chronic ratio variables for both load and stress. Associations between subjective and objective measures were analyzed using Spearman's rank correlation.

Results

Weak to moderate positive associations were found between load and perceived stress (r = 0.19 to 0.46, p < 0.001), and between perceived stress and cortisol (r = 0.10, p = 0.023). Weak negative associations were found between perceived stress and FTCR (r = -0.18 to -0.20, p < 0.001) and between load and FTCR (r = -0.13, p = 0.003). A total of 86% of athletes had positive associations between stress and load (47% weak, 34% moderate, 5% high); 78% between stress and cortisol (27% weak, 22% moderate, 29% high); and 63% demonstrated negative associations between FTCR and load (18% weak, 32% moderate, 13% high).

Conclusion

This study highlights the complexity between subjective and objective measures of stress and load in athletes. Understanding the link between these measures may help coaches and sports scientists streamline athlete monitoring. In cases where moderate to strong associations exist, subjective measures might serve as a reliable substitute for objective ones, making the monitoring process more time- and cost-efficient.

Influence of time-of-day on neuromuscular performance in team sport athletes: a systematic review and meta-analysis

Introduction

Although circadian rhythms have been shown to influence some neuromuscular performance tasks, the time-of-day effect on team sports performance athletes remains equivocal. This study aimed to examine the existing evidence concerning diurnal variations in neuromuscular performance in professional and semi-professional team sports athletes using a meta-analytic approach.

Methods

A literature search was conducted through three different databases: PubMed, SportDiscus and Web of Science. Article selection was made based on the following inclusion criteria: team sports athletes, professional or semi-professional athletes, neuromuscular performance, testing protocols and time-of-day testing times. Neuromuscular performance parameters such vertical jump capacity (i.e., squat and countermovement jump), agility and isometric strength were included in the analysis. Testing protocols that specifically assessed these parameters across morning (AM) and late afternoon/evening (PM) periods were considered were extracted from the selected studies.

Results

Ten studies met the inclusion criteria for qualitative synthesis and five for quantitative synthesis. Meta-analysis indicated lower countermovement jump in the AM compared to with PM (mean difference, -1.44; 95% CI -2.80 to -0.08; p = 0.04) and higher agility performance (mean difference 0.42; 95% CI 0.09-0.74; p = 0.01) in PM comparing with AM. No differences were reported in isometric strength and squat jump performance (p > 0.05).

Conclusion

Neuromuscular performance is higher in the late afternoon or early evening compared to morning schedules in team sport athletes. Hence, time-of-day variations need to be considered when evaluating neuromuscular performance in professional and semi-professional team sports athletes.

A Muscle Physiology-Based Framework for Quantifying Training Load in Resistance Exercises

BACKGROUND

Objective training load (TL) indexes used in resistance training lack physiological significance. This study was aimed to provide a muscle physiology-based approach for quantifying TL in resistance exercises (REs).

METHODS

Following individual torque-velocity profiling, fifteen participants (11 healthy males, stature: 178.36 ± 3.95 cm, and body mass (BM): 77.48 ± 7.74 kg; 4 healthy females, stature: 169.25 ± 5.03 cm, and body mass: 60.62 ± 3.91 kg) performed isokinetic leg extension exercise sessions at low, moderate, and high intensities (LI, MI, and HI, respectively). Systemic and local physiological responses were measured, and sessions were volume-equated according to the "volume-load" (VL) method.

RESULTS

Significant differences were found between sessions in terms of mechanical work (p<0.05 and p<0.001, for LI-MI and MI-HI, respectively), averaged normalised torque (p<0.001), mechanical impulse (p<0.001), and rate of force development (RFD, p<0.001 for LI-MI). RFD was mainly impacted by the accumulation of repetitions. Muscle function impairments mainly occurred at low intensities-long series, and high intensities, supported by greater RFD rate decay and changes in electromyographic activity. Therefore, accounting for muscle fatigue kinetics within objective TL indexes and using dimension reduction methods better described physiological responses to RE.

CONCLUSIONS

A generic equation of muscle fatigue rise could add value to TL quantification in RE. Considering other training-related information and TL indexes stands essential, applicable to field situations and supports the multidimensional facet of physiological responses to RE.

Salivary testosterone and cortisol responses to seven weeks of practical blood flow restriction training in collegiate American football players

Purpose

The purpose of this study was to examine the effects of a 7-week supplemental BFR training intervention on both acute and chronic alterations in salivary testosterone (sTes) and cortisol (sCort) in collegiate American football players.

Methods

58 males were divided into 4 groups: 3 completed an upper- and lower-body split resistance training routine (H, H/S, H/S/R; H = Heavy, S = Supplemental, R = BFR), with H/S/R performing end-of-session practical BFR training, and H/S serving as the volume-matched non-BFR group. The final group (M/S/R) completed modified resistance training programming with the same practical BFR protocol as H/S/R. Athletes were further split into AM and PM training groups based upon their pre-determined training schedules, in cooperation with University strength and conditioning staff. Practical BFR consisted of end-of-session barbell bench press and back squat using 20% 1 repetition maximum (1RM) for 30-20-20-20 repetitions across 4 sets, with 45-seconds rest. Saliva samples were taken pre- and post- the first lower-body training sessions in week 1 and week 7 (i.e., test 1 and test 2) of the program, yielding four total. sTes and sCort were analyzed using 4-way (4 × 2 × 2 × 2) mixed model ANOVA's.

Results

Hormonal variables all exhibited main effects for time-of-day (p < 0.001). A significant group × time interaction effect (F3,50 = 3.246, p < 0.05) indicated increases in sTes post-training cycle for the H/S/R group only. Further, PM post-exercise sCort decreased from test 1 to test 2 (nmol·L-1: 95% CI: PM test 1 post-exercise = 10.7-17.1, PM test 2 post-exercise = 5.0-8.9). For the testosterone-to-cortisol ratio (T/C), AM pre-exercise was lower than PM (p < 0.05), with no change in post-exercise T/C for both AM and PM conditions when collapsed across testing times.

Discussion

Overall, these findings suggest an ecologically valid method of BFR implementation is capable of inducing heightened concentrations of sTes in well-resistance trained American football athletes, providing additional insight on possible physiological mechanisms underpinning BFR's ability to elicit beneficial muscle hypertrophy and maximal strength adaptations when performed during regimented training programs. Additionally, notable rises in T/C, and a null sCort response post-exercise were observed post-program for all groups, possibly indicative of positive physiological adaptation.

Effects of human concurrent aerobic and resistance training on cognitive health: A systematic review with meta-analysis

Background

The rising prevalence of cognitive decline and neurodegenerative diseases, projected to affect 150 million individuals by 2050, highlights the urgent need to enhance neurocognitive health. While both aerobic and resistance training are recognized as effective strategies, their combined effects on cognition remain underexplored.

Objective

This study aimed to determine if concurrent aerobic and resistance training (CT) is effective in enhancing cognitive function.

Methods

Seven English and three Chinese databases were searched from inception to August 2024. Randomised controlled trials (RCTs) examining the effects of CT on global cognition across diverse populations were included. A meta-analysis was performed using a random-effects model in R and Stata, supplemented by subgroup and meta-regression analyses to explore variability.

Results

The meta-analysis included 35 RCTs with 5,734 participants, revealing a positive effect of CT on global cognition (g = 0.32, 95% CI: 0.17-0.46, p < 0.001). Notably, older adults (≥65 years) exhibited greater cognitive benefits (g = 0.33; 95% CI: 0.14-0.51, p < 0.05) compared to younger populations. Significant effects were also observed in clinical populations (g = 0.28; 95% CI: 0.11-0.46, p < 0.001). Exercise frequency and duration positively influenced outcomes, with medium-length interventions (13-26 weeks) demonstrating significant effects (g = 0.21; 95% CI: 0.05-0.37, p = 0.011).

Conclusion

The findings indicate that CT significantly enhances cognitive health, particularly in older adults and clinical populations. Prioritizing strength training, implementing short- to medium-term interventions (4-26 weeks), and maintaining session durations of 30-60 minutes are crucial for optimizing cognitive benefits.

The Effects of CrossFit® Practice on Physical Fitness and Overall Quality of Life

We have examined the impact of CrossFit® workout sessions on physical fitness, comparing the obtained outcomes with the recommendations of the American College of Sports Medicine. In addition, we provide suggestions to improve training monitoring, as well as practical applications for researchers, coaches and practitioners. CrossFit® imposes high cardiorespiratory and metabolic demands, promoting improvements in circulatory capacity, oxidative metabolism and muscular endurance. Sustained elevations in heart rate contribute to cardiovascular conditioning, while a post-exercise hypotensive effect may help to reduce cardiovascular risks. Structured CrossFit® programs have led to improvements in maximal strength and muscular endurance, with substantial increases in squat performance observed in both untrained and recreationally active individuals. In addition, CrossFit® improves mental health through its motivating community. However, the high metabolic demands, increased creatine kinase levels and reduced performance in the countermovement jump reveal that muscle damage and neuromuscular fatigue can persist for up to 48 h. Balancing these intense sessions with adequate recovery is crucial, as improper management may lead to overtraining and compromise fitness gains. Future research should explore long-term cardiovascular adaptations, differences in gains and recovery between males and females and the application of real-time biomarker and artificial intelligence technologies to improve the training efficiency and safety. Machine learning algorithms could further personalize feedback, adapting to each individual's biomechanics and physiological responses over time.

The triad of physical activity: An optimal combination for cardiovascular health

The combination of moderate to vigorous physical activity with muscle-strengthening physical activity is increasingly recognized for its significant impact on cardiovascular health. This narrative review synthesizes current evidence to compare the cardiovascular benefits of combined physical activity versus singular forms, especially in primary prevention. The main focus is on hormonal, nervous, genetic, and molecular adaptations, critical mechanisms underlying the body's response to physical activity. Our findings endorse superior benefits for combined moderate to vigorous and muscle-strengthening physical activity for preventing cardiovascular disease (CVD). This combined approach synergistically enhances cardiovascular function and more effectively reduces risk factors than either activity alone. While more research is needed to distinguish between moderate and vigorous activity levels in combination with muscle-strengthening physical activity, current evidence supports comprehensive physical activity guidelines that maximize cardiovascular health. These findings highlight the importance of integrated physical activity regimens in public health strategies and clinical practice to mitigate the global CVD burden.

Acute Alpha-Glycerylphosphorylcholine Supplementation Enhances Cognitive Performance in Healthy Men

BACKGROUND

Choline is an essential nutrient required for proper cell functioning. Due to its status as a precursor to acetylcholine, an important neurotransmitter connected to cognition and neuromuscular function, maintaining or enhancing choline levels is of interest. Supplementation with alpha-glycerylphosphorycholine (A-GPC) can maintain choline levels, but its ability to offer support towards cognition remains an area of ongoing research.

METHODS

Using a randomized, double-blind, placebo-controlled, crossover approach, 20 resistance-trained males (31.3 ± 11.0 years, 178.6 ± 7.3 cm, 84.6 ± 11.4 kg, 15.4 ± 5.6% body fat) consumed either a placebo (PL), 630 mg A-GPC (HD), or 315 mg (LD) A-GPC (GeniusPure®, NNB Nutrition, Nanjing, China). After resting hemodynamic assessments, participants took their assigned dose and had cognitive assessments (Stroop, N-Back, and Flanker), visual analog scales, and hemodynamics evaluated 60 min after ingestion. All participants then warmed up and completed vertical jumps and bench press throws before completing a bout of lower-body resistance exercise (6 × 10 repetitions using the Smith squat at a load of 70% 1RM). Venous blood was collected 5, 15, 30, and 60 min after completion of the squat protocol to evaluate changes in growth hormones, and follow-up visual analog scales and cognitive measurements were evaluated 30 min after completing the exercise bout.

RESULTS

When compared to PL, changes in Stroop total score were statistically greater after HD (13.0 ± 8.2 vs. 5.2 ± 9.0, p = 0.013, d = 0.61) and LD (10.8 ± 7.7 vs. 5.2 ± 9.0, p = 0.046, d = 0.48) administration, in addition to significantly faster times to complete the Stroop test in the HD group when compared to PL (-0.12 ± 0.09 s vs. -0.05 ± 0.09 s, p = 0.021, d = 0.56). No significant differences between groups were found for the Flanker and N-Back assessments, while a tendency was observed for HD to have faster reaction times when compared to PL during the Flanker test. No group differences were realized for visual analog scales, physical performance, or growth hormone. Statistically significant changes in heart rate and blood pressure were observed in all groups, with all recorded values aligning with clinically accepted normative values.

CONCLUSIONS

HD and LD A-GPC supplementation significantly increased cognitive performance in a group of young, healthy males as measured by changes in the Stroop Total Score and completion time of the Stroop test. These results offer unique insight into the potential for A-GPC to acutely increase cognition in a group of young, healthy males. While previous research has indicated potential for A-GPC to acutely improve cognition in clinical populations, extending these outcomes to healthy individuals can be potentially meaningful for a wide variety of populations such as athletes, race car drivers, military operators, and other non-athletic populations who desire and have a need to improve their mental performance. This study was retrospectively registered as NCT06690619 on clinicaltrials.gov.

Effects of Cluster vs. Traditional Sets Complex Training on Physical Performance Adaptations of Trained Male Volleyball Players

This study aimed to examine the impact of different set configurations during combination of resistance and plyometric training (complex [COX]) on jumping ability, power output, strength, and hormonal adaptations in young male volleyball players after a 6-week training period. A randomized controlled trial was conducted with twenty-four trained male volleyball players under the age of 19, who were assigned to one of two groups for lower-body COX training: cluster sets (CS-COX: n = 8) or traditional sets (TS-COX: n = 8), with an additional active control group (CON: n = 8). The players underwent evaluations for countermovement vertical jump (CMVJ), spike jump (SPJ), T-test change of direction speed (T-test CODS), one repetition maximum (1RM) in the back squat and leg press, and the Wingate Anaerobic Test before and after the 6-week training intervention (12 sessions in total). Blood samples were also collected before and after training to assess resting testosterone and cortisol responses. Following the training, both the CS-COX and TS-COX groups exhibited significantly greater (p = 0.001) changes than the CON group in the variables, while similar improvements in maximal strength, mean power output, and testosterone adaptations were observed following the training (p < 0.05). Moreover, the CS-COX group demonstrated greater improvements in CMVJ (effect size [ES] = 0.36), SPJ (ES = 0.06), T-test CODS (ES = -0.60), and peak power output (ES = 0.72), along with greater reductions in resting cortisol (ES = -0.30) levels compared to the TS-COX group after the 6-week intervention (p < 0.05). In conclusion, the results indicate that incorporating cluster sets during COX training sessions led to more favorable changes in bio-motor ability, peak power output, and cortisol adaptations, with greater consistency and uniformity in adaptations among the players compared to traditional set configurations.

Effects of Movement Sonification Auditory Feedback on Repetitions and Brain Activity During the Bench Press

ABSTRACT

Garner, C, Nachtegall, A, Roth, E, Sterenberg, A, Kim, D, Michael, T, and Lee, S. Effects of movement sonification auditory feedback on repetitions and brain activity during the bench press. J Strength Cond Res 38(12): 2022-2028, 2024-Auditory stimulation and feedback have been found to enhance aspects of motor performance such as motor learning, sense of agency, and movement execution. While music is the most common form of auditory stimulation during exercise, movement sonification (MoSo) may better facilitate motor performance through its use of music elements representing dynamic movements. Despite evidence of MoSo's benefits to motor performance, little is known about MoSo's influence on resistance exercise. The purpose of this research was to investigate the effects of MoSo auditory feedback on repetitions and brain activity during bench press. Twenty men performed bench press to failure in 3 sound conditions (no-sound, self-selected music, and MoSo). Repetition maximum (RM) was measured, and brain activity was analyzed using beta power spectral density (PSD) and frontal alpha asymmetry (FAA). A 1-way repeated measures analysis of variance (ANOVA) was conducted to compare data across sound conditions. To gain a deeper understanding of brain activity during bench press, a 2-way repeated measures ANOVA was performed to investigate changes in beta PSD and FAA over time using sound and timepoint as independent variables. A 1-way ANOVA showed that FAA in MoSo was significantly higher than in music and no-sound; however, no statistically significant differences were observed in RM and beta PSD between conditions. A 2-way ANOVA revealed that beta PSD and FAA increased significantly as bench press repetitions approached failure. Our study suggests that MoSo auditory feedback may not improve bench press repetitions, but it may increase brain activity during bench press better than listening to music.

Effects of Assisted Walking Exercise in Chronic Dependent Ambulatory Stroke Survivors: A Mini-Review

Background

Assisted walking exercise programs are widely recommended in rehabilitation guidelines for stroke survivors. However, most evidence supporting these programs primarily focuses on ambulatory stroke survivors or those dependent ambulatory in acute and subacute stages. There is a notable gap in the application of walking exercise programs for chronic dependent ambulatory stroke survivors despite potential benefits in reducing sedentary behavior and improving rehabilitation outcomes. Thus, this literature review aims to summarize the existing evidence on the feasibility and efficacy of assisted walking exercise programs for chronic stroke survivors who are dependent ambulators.

Methods

Six major databases were searched for clinical trials related to assisted walking exercise and chronic dependent ambulatory stroke.

Results

Seven studies (evidence with low- to moderate-quality) involving 91 chronic dependent ambulatory stroke subjects are included in this review.

Conclusions

These studies indicated that assisted walking exercise is feasible to perform by chronic dependent ambulatory stroke survivors and can induce continued motor recovery and functional improvement. However, the mixed and limited evidence from existing research underscores the need for future high-quality randomized controlled trials with standardized designs and outcome measures to establish evidence-based walking programs for this population.

"Investigating the combined effects of scapular-focused training and Mulligan mobilization on shoulder impingement syndrome" a three-arm pilot randomized controlled trial

OBJECTIVES

To assess whether the combination of scapular-focused training and mulligan mobilization (SFTMM) improves pain and proprioception compared to scapular-focused training (SFT) and a control group in female rock climbers with shoulder impingement syndrome (SIS).

DESIGN

Three-arm randomized controlled trial (RCT).

SETTING

Outpatient setting.

SUBJECTS

Individuals were randomly assigned to SFTMM, SFT alone, and control group.

INTERVENTIONS

8 weeks of SFTMM and SFT.

MAIN MEASURES

Outcome measures were pain and proprioception.

RESULTS

The results revealed significant differences in pain scores and proprioception among female rock climbers with SIS who participated in SFTMM, SFT, and a control group (F(2, 32) = 81.01, p = 0.001, η2 = 0.83 for pain scores; F(2, 32) = 178.2, p = 0.001, η2 = 0.91 for proprioception scores). Post-hoc tests via the Bonferroni test indicated that both SFTMM and SFT significantly reduced pain levels (p = 0.001) and improved proprioception levels (p = 0.001) compared with the control group. There was no significant difference in pain scores and proprioception between the SFTMM group and the SFT group (p > 0.05).

CONCLUSIONS

In conclusion, the study indicates that SFTMM significantly reduces pain and improves proprioception in female rock climbers with SIS, as shown by notable changes compared to the control group. However, no statistically significant difference was found between the SFTMM (combined intervention) and SFT alone. Therefore, while the incorporation of SFT and MM shows promise; further research is needed to fully understand its long-term benefits and clinical implications.

ETHICAL CODE REGISTRATION

The study was approved at Ethics.

RESEARCH

ac.ir, code: IR.SSRC.REC.1402.170 on 2023-10-22.

The Effects of Normobaric Hypoxia on the Acute Physiological Responses to Resistance Training: A Narrative Review

ABSTRACT

Allsopp, GL, Britto, FA, Wright, CR, and Deldicque, L. The effects of normobaric hypoxia on the acute physiological responses to resistance training: a narrative review. J Strength Cond Res 38(11): 2001-2011, 2024-Athletes have used altitude training for many years as a strategy to improve endurance performance. The use of resistance training in simulated altitude (normobaric hypoxia) is a growing strategy that aims to improve the hypertrophy and strength adaptations to training. An increasing breadth of research has characterized the acute physiological responses to resistance training in hypoxia, often with the goal to elucidate the mechanisms by which hypoxia may improve the training adaptations. There is currently no consensus on the overall effectiveness of hypoxic resistance training for strength and hypertrophy adaptations, nor the underlying biochemical pathways involved. There are, however, numerous interesting physiological responses that are amplified by performing resistance training in hypoxia. These include potential changes to the energy system contribution to exercise and alterations to the level of metabolic stress, hormone and cytokine production, autonomic regulation, and other hypoxia-induced cellular pathways. This review describes the foundational exercise physiology underpinning the acute responses to resistance training in normobaric hypoxia, potential applications to clinical populations, including training considerations for athletic populations. The review also presents a summary of the ideal training parameters to promote metabolic stress and associated training adaptations. There are currently many gaps in our understanding of the physiological responses to hypoxic resistance training, partly caused by the infancy of the research field and diversity of hypoxic and training parameters.

Acute and Chronic Changes in Muscle Androgen Receptor Markers Are Not Associated with Muscle Hypertrophy in Women and Men

PURPOSE

Androgen receptor (AR) expression and signaling have been regarded as a mechanism for regulating muscle hypertrophy. However, little is known about the associations between acute and chronic changes in skeletal muscle total AR, cytoplasmic AR (cAR), nuclear AR (nAR), and AR DNA-binding (AR-DNA) induced by resistance training (RT) and hypertrophy outcomes in women and men. This study aimed to investigate the acute and chronic effects of RT on skeletal muscle total AR, cAR, and nAR contents and AR-DNA in women and men. In addition, we investigated whether these acute and chronic changes in these markers were associated with muscle hypertrophy in both sexes.

METHODS

Nineteen women and 19 men underwent 10 wk of RT. Muscle biopsies were performed at baseline, 24 h after the first RT session, and 96 h after the last session. AR, cAR, and nAR were analyzed using Western blotting, and AR-DNA using an ELISA-oligonucleotide assay. Fiber cross-sectional area (fCSA) was analyzed through immunohistochemistry and muscle cross-sectional area (mCSA) by ultrasound.

RESULTS

At baseline, men demonstrated greater nAR than women. Baseline cAR was significantly associated with type II fCSA hypertrophy in men. Acutely, both sexes decreased AR and cAR, whereas men demonstrated greater decreases in nAR. After 10 wk of RT, AR, and nAR remained unchanged, men demonstrated greater cAR compared with women, and both sexes decreased AR-DNA activity. Acute and chronic changes in AR markers did not correlate with muscle hypertrophy (type I/II fCSA and mCSA) in women or men.

CONCLUSIONS

Baseline cAR content may influence hypertrophy in men, whereas neither RT-induced acute nor chronic changes in AR, cAR, nAR, and AR-DNA are associated with muscle hypertrophy in women or men.

Hormones, Hypertrophy, and Hype: An Evidence-Guided Primer on Endogenous Endocrine Influences on Exercise-Induced Muscle Hypertrophy

We review the evidence indicating that endogenous changes in these hormones, including testosterone, growth hormone, insulin growth factor-1, and estrogen, and their proposed anabolic effects contribute to and augment resistance exercise training (RET)-induced hypertrophy. Additionally, we provide recommendations for gold-standard methodological rigor to establish best practices for verifying menstrual phases as part of their research, ultimately enhancing our understanding of the impact of ovarian hormones on RET-induced adaptations.

Effects of circuit weight training by intensity on stress hormones and antioxidant capacity in high-school wrestlers

We aimed to investigate the effects of 8-week circuit weight training by intensity on blood stress hormones and antioxidant capacity in high-school wrestlers. This study involved 27 male wrestlers with >2 years of wrestling experience who were randomly assigned to either a low intensity (n=13) or a high-intensity circuit weight training group (n=14). The participants performed circuit weight training for 60 min per session, 3 times per week for 8 weeks. The low- and high-intensity circuit weight training exercises were performed at 50%-60% and 70%-80% of one-repetition maximum for 10 stations, respectively, and 8-15 repeated sessions per station were performed in order. No changes were observed in adrenocorticotropic hormone (ACTH), cortisol, epinephrine, and norepinephrine levels between the two training groups. When compared to levels before the training, ACTH and epinephrine levels decreased, whereas cortisol levels increased. However, no difference was observed in norepinephrine levels. Further, no differences were observed in malondialdehyde (MDA) and glutathione peroxidase (GPX) levels between the two groups. However, MDA and GPX levels were increased from those before training. Changes in superoxide dismutase levels were observed between the two groups, but the change was significant only in the high-intensity circuit weight training group. Long-term training did not increase lipid peroxidation, but increased the activity of antioxidant enzymes that defend against oxidative stress. The antioxidant defense system in tissues can be regulated by exercise intensity as well as physical training status.

Cross-education of lower limb muscle strength following resistance exercise training in males and females: A systematic review and meta-analysis

Cross-education describes the training of one limb that leads to performance enhancements in the contralateral untrained limb, driven by neural changes rather than muscle adaptation. In this systematic review and meta-analysis, we aimed to evaluate the efficacy of cross-education (vs. a control group) via resistance exercise training (RET) for improving muscle strength in the untrained lower limb of healthy males and females. A literature search from inception to September 2023 was conducted using MEDLINE (via PubMed), the Cochrane Library (CENTRAL), Web of Science (Core Database), Scopus, EBSCO-host, and Ovid-EMBASE. Independent screening, data extraction and quality assessment were conducted. The measured outcomes were change in one-repetition maximum (1-RM) load, maximum voluntary contraction (MVC), and concentric, eccentric and isometric peak torque. Change in muscle structure (pennation angle and muscle thickness) was also analysed. A total of 29 studies were included. The pooled effect size from the random-effects model shows that cross-education significantly increased 1-RM compared to the control group (standardised mean difference (SMD): 0.59, 95% CI: 0.22-0.97; P = 0.002). Cross-education also significantly improved MVC (SMD: 0.55, 95% CI: 0.16-0.94; P = 0.006), concentric (SMD: 0.61, 95% CI: 0.39-0.84; P < 0.00001), eccentric (SMD: 0.39, 95% CI: 0.13-0.64; P = 0.003) and isometric (SMD: 0.45, 95% CI: 0.26-0.64; P < 0.00001) peak torque, each compared to the control group. When RET was categorised as eccentric or concentric, subgroup analysis showed that only eccentric training was associated with significantly increased isometric peak torque via cross-education (SMD: 0.37, 95% CI: 0.13-0.61; P = 0.003) (concentric, SMD: 0.33, 95% CI: -0.09 to 0.74; P = 0.12). This systematic review and meta-analysis emphasise the potency of cross-education for improving lower limb muscle strength. These findings have potential implications for clinical situations of impaired unilateral limb function (e.g., limb-casting or stroke). Future work exploring the mechanisms facilitating these enhancements will help to develop optimised rehabilitation protocols.

Digital music and movement intervention to improve health and wellbeing in older adults in care homes: a pilot mixed methods study

BACKGROUND

Low physical activity among older adults is related to adverse health outcomes such as depression and loneliness, poor physical function and increased risk of falls. This study was designed to increase physical activity through a digital, group-based, physical activity and music intervention and to examine its effectiveness on social, mental and physical health outcomes.

METHODS

Participants were 34 older adults (65 years +) recruited across four care homes in Scotland to a pilot study. Surveys were administered at baseline and post-intervention, comprising measures of fear of falling, depression and anxiety, loneliness, sleep satisfaction and quality of life. A battery of physical function tests and saliva sampling for cortisol and dehydroepiandrosterone hormone analysis were also conducted at each time point. Additionally, process evaluation measures (recruitment, intervention fidelity, attendance, retention rates and safety) were monitored. The intervention comprised 12 weeks of three prescribed digital sessions per week: movement and music (n = 2) and music-only (n = 1), delivered by an activity coordinator in the care home. Post-intervention interviews with staff and participants were conducted to gain qualitative data on the acceptability of the intervention.

RESULTS

An average of 88% of prescribed sessions were delivered. Pre- to post-intervention intention-to-treat analysis across all participants revealed significant improvements in anxiety, salivary DHEA, fear of falling and loneliness. There were no significant improvements in health-related quality of life, perceived stress, sleep satisfaction or physical function tests, including handgrip strength. Qualitative analysis highlighted benefits of and barriers to the programme.

CONCLUSIONS

The digital movement and music intervention was deemed acceptable and delivered with moderate fidelity, justifying progression to a full-scale trial. Although a proper control group would have yielded more confident causal relationships, preliminary psychosocial and biological effects were evident from this trial. To show significant improvements in physical function, it is likely that a bigger sample size providing sufficient power to detect significant changes, greater adherence, longer intervention and/or higher exercise volume may be necessary.

TRIAL REGISTRATION

The trial is registered at ClinicalTrials.gov, number NCT05601102 on 01/11/2022.

A Randomized Controlled Trial to Determine the Impact of Resistance Training versus Aerobic Training on the Management of FGF-21 and Related Physiological Variables in Obese Men with Type 2 Diabetes Mellitus

Fibroblast growth factor 21 (FGF-21) has been suggested as a potential therapeutic target for insulin resistance in health-related metabolic disorders such as type 2 diabetes. Despite the metabolic effects of resistance (RT) and aerobic training (AT) on diabetes symptoms, uncertainty exists regarding the superiority of effects manifested through these training approaches on FGF-21 and biochemical and physiological variables associated with metabolic disorders in men diagnosed with type 2 diabetes. This study aimed to investigate the impact of a 12-week RT and AT on FGF-21 levels and symptoms associated with metabolic disorders in male individuals diagnosed with type 2 diabetes. Thirty-six sedentary obese diabetic men (40 to 45 years old) were matched based on the level of FGF-1. They and were randomly divided into two training groups (RT, n = 12 and AT, n = 12) performing three days per week of moderate-intensity RT or AT for 12 weeks and an inactive control group (n = 12). Both training interventions significantly improved FGF-21, glucose metabolism, lipid profile, hormonal changes, strength, and aerobic capacity. Subgroup analysis revealed that RT had greater adaptive responses (p < 0.01) in fasting blood sugar (ES = -0.52), HOMA-IR (ES = -0.87), testosterone (ES = 0.52), cortisol (ES = -0.82), FGF-21 (ES = 0.61), and maximal strength (ES = 1.19) compared to AT. Conversely, AT showed greater changes (p < 0.01) in cholesterol (ES = -0.28), triglyceride (ES = -0.64), HDL (ES = 0.46), LDL (ES = -0.73), and aerobic capacity (ES = 1.18) compared to RT. Overall, both RT and AT interventions yielded significant moderate to large ES in FGF-21 levels and enhanced the management of biochemical variables. RT is an effective method for controlling FGF-21 levels and glucose balance, as well as for inducing hormonal changes. On the other hand, AT is more suitable for improving lipid profiles in overweight men with type 2 diabetes mellitus.

Hemodynamic Effects of Intermittent Pneumatic Compression on Athletes: A Double-Blinded Randomized Crossover Study

PURPOSE

There are multiple postexercise recovery technologies available in the market based on the assumption of blood-flow enhancement. Lower-limb intermittent pneumatic compression (IPC) has been widely used, but the available scientific evidence supporting its effectiveness remains scarce, requiring a deeper investigation into its underlying mechanisms. The aim of this study was to assess the hemodynamic effects caused by the use of IPC at rest.

METHODS

Twenty-two soccer and track and field athletes underwent two 15-minute IPC protocols (moderate- [80 mm Hg] and high-pressure [200 mm Hg]) in a randomized order. Systolic peak velocity, end-diastolic peak velocity, arterial diameter, and heart rate were measured before, during (at the eighth minute), and 2 minutes after each IPC protocol.

RESULTS

Significant effects were observed between before and during (eighth minute) the IPC protocol for measures of systolic (P < .001) and end-diastolic peak velocities (P < .001), with the greater effects observed during the high-pressure protocol. Moreover, 2 minutes after each IPC protocol, hemodynamic variables returned to values close to baseline. Arterial diameter presented significant differences between pressures during the IPC protocols (P < .05), while heart rate remained unaltered.

CONCLUSION

IPC effectively enhances transitory blood flow of athletes, particularly when applying high-pressure protocols.

The Effects of Blood Flow Restriction Aerobic Exercise on Body Composition, Muscle Strength, Blood Biomarkers, and Cardiovascular Function: A Narrative Review

Blood flow restriction exercise has emerged as a promising alternative, particularly for elderly individuals and those unable to participate in high-intensity exercise. However, existing research has predominantly focused on blood flow restriction resistance exercise. There remains a notable gap in understanding the comprehensive effects of blood flow restriction aerobic exercise (BFRAE) on body composition, lipid profiles, glycemic metabolism, and cardiovascular function. This review aims to explore the physiological effects induced by chronic BFRAE. Chronic BFRAE has been shown to decrease fat mass, increase muscle mass, and enhance muscular strength, potentially benefiting lipid profiles, glycemic metabolism, and overall function. Thus, the BFRAE offers additional benefits beyond traditional aerobic exercise effects. Notably, the BFRAE approach may be particularly suitable for individuals with low fitness levels, those prone to injury, the elderly, obese individuals, and those with metabolic disorders.

Movement pattern definitions for resistance training behavior measurement in diabetes

Type 2 diabetes can result in debilitating vascular complications, and resistance training (RT) is an effective therapy for improving cardiovascular outcomes. However, only 10-30% of adults meet the public health guidance for RT. While current RT guidelines focus on targeting major muscle groups, guidance specific to simplified movement categorization may augment understanding of RT programming and improve uptake and outcomes. Current movement pattern definitions and descriptions lack clarity, accuracy, and consistency. This paper proposes movement definitions and descriptions to be used for RT intervention design and prescription, and includes the following categories: hip, knee, ankle, vertebral column, vertical push, horizontal push, vertical pull, and horizontal pull. These categories are intended to aid clinicians, researchers, and trainers in RT surveillance and RT intervention design for improving vascular complications in type 2 diabetes. Simplified RT program design using these categories may also facilitate greater RT program understanding and adherence for patients.

Effect of Single Session of Swedish Massage on Circulating Levels of Interleukin-6 and Insulin-like Growth Factor 1

Massage therapy increases muscle blood flow and heat, relieving pain, improving immune function, and increasing vagal activity. The mechanisms are unclear. Muscles release cytokines and other peptides called myokines. These myokines exert their effects on different tissues and organs in para-, auto-, and endocrine fashion. The aim of this intervention study was to investigate if massage therapy affects circulating myokine levels. A total of 46 healthy, normal-weight subjects (15 men) aged 18-35 were recruited. Forty-five minutes of massage Swedish therapy was applied to the back and hamstrings. Blood samples via cannula were taken at the baseline, during the massage (30 min), end of the massage (45 min), and 30 min and 1 h after the massage. Interleukin 6 (IL-6) and insulin-like growth factor 1 (IGF-1) were measured as surrogate markers by ELISAs. There was a significant increase in IL-6 from 1.09 pg/mL to 1.85 pg/mL over time (Wilks' Lambda Value 0.545, p < 0.000; repeated measures ANOVA). Pair-wise comparisons showed a significant increase after 1 h of massage. No significant increase was observed in IGF-1 levels. The change in myokine levels was not correlated with muscle mass (p = 0.16, 0.74). The increase in IL-6 suggests that there might be anti-inflammatory effects, affecting glucose and lipid metabolism pathways via IL-6 signaling to muscles, fat tissue, and the liver.

Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy

We systematically searched the literature for studies with a randomized design that compared different inter-set rest interval durations for estimates of pre-/post-study changes in lean/muscle mass in healthy adults while controlling all other training variables. Bayesian meta-analyses on non-controlled effect sizes using hierarchical models of all 19 measurements (thigh: 10; arm: 6; whole body: 3) from 9 studies meeting inclusion criteria analyses showed substantial overlap of standardized mean differences across the different inter-set rest periods [binary: short: 0.48 (95%CrI: 0.19-0.81), longer: 0.56 (95%CrI: 0.24-0.86); Four categories: short: 0.47 (95%CrI: 0.19-0.80), intermediate: 0.65 (95%CrI: 0.18-1.1), long: 0.55 (95%CrI: 0.15-0.90), very long: 0.50 (95%CrI: 0.14-0.89)], with substantial heterogeneity in results. Univariate and multivariate pairwise meta-analyses of controlled binary (short vs. longer) effect sizes showed similar results for the arm and thigh with central estimates tending to favor longer rest periods [arm: 0.13 (95%CrI: -0.27 to 0.51); thigh: 0.17 (95%CrI: -0.13 to 0.43)]. In contrast, central estimates closer to zero but marginally favoring shorter rest periods were estimated for the whole body [whole body: -0.08 (95%CrI: -0.45 to 0.29)]. Subanalysis of set end-point data indicated that training to failure or stopping short of failure did not meaningfully influence the interaction between rest interval duration and muscle hypertrophy. In conclusion, results suggest a small hypertrophic benefit to employing inter-set rest interval durations >60 s, perhaps mediated by reductions in volume load. However, our analysis did not detect appreciable differences in hypertrophy when resting >90 s between sets, consistent with evidence that detrimental effects on volume load tend to plateau beyond this time-frame. Systematic Review Registration: OSF, https://doi.org/10.17605/OSF.IO/YWEVC.

Vertical Strength Transfer Phenomenon Between Upper Body and Lower Body Exercise: Systematic Scoping Review

BACKGROUND

There are a myriad of exercise variations in which upper body (UB) and lower body (LB) exercises have been intermittently used. However, it is still unclear how training of one body region (e.g. LB) affects adaptations in distant body areas (e.g. UB), and how different UB and LB exercise configurations could help facilitate physiological adaptations of either region; both referred to in this review as vertical strength transfer.

OBJECTIVE

We aimed to investigate the existence of the vertical strength transfer phenomenon as a response to various UB and LB exercise configurations and to identify potential mechanisms underpinning its occurrence.

METHODS

A systematic search using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) for Scoping Reviews protocol was conducted in February 2024 using four databases (Web of Science, MEDLINE, Scopus and CINAHL) to identify peer-reviewed articles that investigated the vertical strength transfer phenomenon.

RESULTS

Of the 5242 identified articles, 24 studies met the inclusion criteria. Findings suggest that the addition of UB strength training to LB endurance exercise may help preserve power-generating capacity for the leg muscle fibres. Furthermore, systemic endocrine responses to high-volume resistance exercise may beneficially modulate adaptations in precedingly or subsequently trained muscles from a different body region, augmenting their strength gains. Last, strength training for LB could result in improved strength of untrained UB, likely due to the increased central neural drive.

CONCLUSIONS

Vertical strength transfer existence is enabled by neurophysiological mechanisms. Future research should involve athletic populations, examining the potential of vertical strength transfer to facilitate athletic performance and preserve strength in injured extremities.

Acute Hormonal and Inflammatory Responses following Lower and Upper Body Resistance Exercises Performed to Volitional Failure

This study aimed to investigate the effects of a single bench press (BP) vs. leg press (LP) resistance training sessions on testosterone, cortisol, C-reactive protein (CRP) interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) concentrations, and creatine kinase (CK) activity in strength-trained males. Eleven strength-trained males participated in a cross-over randomized trial, undergoing two experimental sessions each consisting of five sets of the BP or the LP exercise to volitional failure with a load corresponding to 50% of one-repetition maximum. Blood samples were taken at baseline (BA), immediately post (POST), and 1 h after the cessation of exercise (POST-1). A significant increase in IL-6 concentration from BA to POST-1 was observed during the LP condition (p = 0.004; effect size [ES] = 0.64). Additionally, a significant main effect of time was found for increasing testosterone concentrations from BA to POST exercise (p = 0.014; ES = 0.25). A significantly lower cortisol concentration at POST-1 compared to POST (p = 0.001; ES = 1.02) was noted in the BP condition. Furthermore, a significantly lower cortisol concentration was found at POST-1 in the BP compared to the LP condition (p = 0.022; ES = 1.3). A significant increase in CK activity was reported from BA to POST (p = 0.024; ES = 0.69) and POST-1 (p = 0.045; ES = 0.55) during the LP condition, and from BA to POST-1 (p = 0.014; ES = 0.96) during the BP condition. No significant differences were found in the CRP (p = 0.659) and TNF-α concentrations (p = 0.487). These results suggest that the amount of muscle mass engaged during the resistance exercise may influence the changes in IL-6 and cortisol concentrations. Larger muscle groups, as engaged in the LP, more likely lead to elevated concentrations of IL-6 myokine.

Acute Resistance Exercise Modifies Extracellular Vesicle miRNAs Targeting Anabolic Gene Pathways: A Prospective Cohort Study

BACKGROUND

Resistance training confers numerous health benefits that are mediated in part by circulating factors. Toward an enhanced molecular understanding, there is growing interest in a class of signaling biomarkers called extracellular vesicles (EV). EVs support physiological adaptations to exercise by transporting their cargo (e.g., microRNA (miRNA)) to target cells. Previous studies of changes in EV cargo have focused on aerobic exercise, with limited data examining the effects of resistance exercise. We examined the effect of acute resistance exercise on circulating EV miRNAs and their predicted target pathways.

METHODS

Ten participants (5 men; age, 26.9 ± 5.5 yr; height, 173.4 ± 10.5 cm; body mass, 74.0 ± 11.1 kg; body fat, 25.7% ± 11.6%) completed an acute heavy resistance exercise test (AHRET) consisting of six sets of 10 repetitions of back squats using 75% one-repetition maximum. Pre-/post-AHRET, EVs were isolated from plasma using size exclusion chromatography, and RNA sequencing was performed. Differentially expressed miRNAs between pre- and post-AHRET EVs were analyzed using Ingenuity Pathway Analysis to predict target messenger RNAs and their target biological pathways.

RESULTS

Overall, 34 miRNAs were altered by AHRET ( P < 0.05), targeting 4895 mRNAs, with enrichment of 175 canonical pathways ( P < 0.01), including 12 related to growth/metabolism (p53, IGF-I, STAT3, PPAR, JAK/STAT, growth hormone, WNT/β-catenin, ERK/MAPK, AMPK, mTOR, and PI3K/AKT) and 8 to inflammation signaling (TGF-β, IL-8, IL-7, IL-3, IL-6, IL-2, IL-17, IL-10).

CONCLUSIONS

Acute resistance exercise alters EV miRNAs targeting pathways involved in growth, metabolism, and immune function. Circulating EVs may serve as significant adaptive signaling molecules influenced by exercise training.

Discussing Conflicting Explanatory Approaches in Flexibility Training Under Consideration of Physiology: A Narrative Review

The mechanisms underlying range of motion enhancements via flexibility training discussed in the literature show high heterogeneity in research methodology and study findings. In addition, scientific conclusions are mostly based on functional observations while studies considering the underlying physiology are less common. However, understanding the underlying mechanisms that contribute to an improved range of motion through stretching is crucial for conducting comparable studies with sound designs, optimising training routines and accurately interpreting resulting outcomes. While there seems to be no evidence to attribute acute range of motion increases as well as changes in muscle and tendon stiffness and pain perception specifically to stretching or foam rolling, the role of general warm-up effects is discussed in this paper. Additionally, the role of mechanical tension applied to greater muscle lengths for range of motion improvement will be discussed. Thus, it is suggested that physical training stressors can be seen as external stimuli that control gene expression via the targeted stimulation of transcription factors, leading to structural adaptations due to enhanced protein synthesis. Hence, the possible role of serial sarcomerogenesis in altering pain perception, reducing muscle stiffness and passive torque, or changes in the optimal joint angle for force development is considered as well as alternative interventions with a potential impact on anabolic pathways. As there are limited possibilities to directly measure serial sarcomere number, longitudinal muscle hypertrophy remains without direct evidence. The available literature does not demonstrate the necessity of only using specific flexibility training routines such as stretching to enhance acute or chronic range of motion.

Resistance Training in the Heat: Mechanisms of Hypertrophy and Performance Enhancement

ABSTRACT

Pryor, JL, Sweet, D, Rosbrook, P, Qiao, J, Hess, HW, and Looney, DP. Resistance training in the heat: Mechanisms of hypertrophy and performance enhancement. J Strength Cond Res 38(7): 1350-1357, 2024-The addition of heat stress to resistance exercise or heated resistance exercise (HRE) is growing in popularity as emerging evidence indicates altered neuromuscular function and an amplification of several mechanistic targets of protein synthesis. Studies demonstrating increased protein synthesis activity have shown temperature-dependent mammalian target of rapamycin phosphorylation, supplemental calcium release, augmented heat shock protein expression, and altered immune and hormone activity. These intriguing observations have largely stemmed from myotube, isolated muscle fiber, or rodent models using passive heating alone or in combination with immobilization or injury models. A growing number of translational studies in humans show comparable results employing local tissue or whole-body heat with and without resistance exercise. While few, these translational studies are immensely valuable as they are most applicable to sport and exercise. As such, this brief narrative review aims to discuss evidence primarily from human HRE studies detailing the neuromuscular, hormonal, and molecular responses to HRE and subsequent strength and hypertrophy adaptations. Much remains unknown in this exciting new area of inquiry from both a mechanistic and functional perspective warranting continued research.

Supplementation Strategies for Strength and Power Athletes: Carbohydrate, Protein, and Amino Acid Ingestion

It is a common belief amongst strength and power athletes that nutritional supplementation strategies aid recovery by shifting the anabolic/catabolic profile toward anabolism. Factors such as nutrient quantity, nutrient quality, and nutrient timing significantly impact upon the effectiveness of nutritional strategies in optimizing the acute responses to resistance exercise and the adaptive response to resistance training (i.e., muscle growth and strength expression). Specifically, the aim of this review is to address carbohydrates (CHOs), protein (PRO), and/or amino acids (AAs) supplementation strategies, as there is growing evidence suggesting a link between nutrient signaling and the initiation of protein synthesis, muscle glycogen resynthesis, and the attenuation of myofibrillar protein degradation following resistance exercise. Collectively, the current scientific literature indicates that nutritional supplementation strategies utilizing CHO, PRO, and/or AA represents an important approach aimed at enhancing muscular responses for strength and power athletes, primarily increased muscular hypertrophy and enhanced strength expression. There appears to be a critical interaction between resistance exercise and nutrient-cell signaling associated with the principle of nutrient timing (i.e., pre-exercise, during, and post-exercise). Recommendations for nutritional supplementation strategies to promote muscular responses for strength and athletes are provided.

PEAK Mood, Mind, and Marks: a pilot study of an intervention to support university students' mental and cognitive health through physical exercise

Introduction

Regular exercise has the potential to enhance university students' mental and cognitive health. The PEAK Mood, Mind and Marks program (i.e., PEAK) is a neuroscience-informed intervention developed using the Behaviour Change Wheel to support students to exercise three or more times per week to benefit their mental and cognitive health. This pilot study assessed the impact of PEAK on exercise, mental and cognitive health, and implementation outcomes.

Methods

PEAK was delivered to 115 undergraduate university students throughout a 12-week university semester. The primary outcome was weekly exercise frequency. Secondary outcomes were: time spent engaged in moderate-vigorous exercise, sedentary behaviour and perceived mental health and cognitive health. All were measured via online self-report questionnaires. Qualitative interviews with 15 students investigated influences on engagement, the acceptability and appropriateness of PEAK, and its mechanisms of behaviour change. Paired t-tests, Wilcoxon Signed-Rank tests and template analysis were used to analyse quantitative and qualitative data, respectively.

Results

On average, 48.4% of students engaged in the recommended frequency of three or more exercise sessions per week. This proportion decreased towards the end of PEAK. Sedentary behaviour significantly decreased from baseline to end-point, and moderate-vigorous exercise significantly increased among students' who were non-exercisers. Mental wellbeing, stress, loneliness, and sense of belonging to the university significantly improved. There were no significant changes in psychological distress. Concentration, memory, and productivity significantly improved. Sixty-eight percent of students remained engaged in one or more components of PEAK at end-point. Qualitative data indicated students found PEAK to be acceptable and appropriate, and that it improved aspects of their capability, opportunity, and motivation to exercise.

Conclusions

Students are receptive to an exercise-based program to support their mental and cognitive health. Students exercise frequency decreased; however, these figures are likely a conservative estimate of students exercise engagement. Students valued the neuroscience-informed approach to motivational and educational content and that the program's goals aligned with their academic goals. Students identified numerous areas PEAK's content and implementation can be optimised, including use of a single digital delivery platform, more opportunities to connect with peers and to expand the content's cultural inclusivity.

Effect of ADORA2A Gene Polymorphism and Acute Caffeine Supplementation on Hormonal Response to Resistance Exercise: A Double-Blind, Crossover, Placebo-Controlled Study

Previous studies have reported that TT genotype carriers of the adenosine A2a receptor (ADORA2A) gene rs5751876 polymorphism have better ergogenic and anti-inflammatory responses to caffeine intake compared to C allele carriers. The aim of the present study was twofold: (1) to investigate the association of the ADORA2A rs5751876 polymorphism with acute caffeine supplementation on hormonal (growth hormone and testosterone) response to resistance exercise (RE); (2) to examine the relationship between the rs5751876 polymorphism and the resting levels of growth hormone and testosterone in athletes who are light caffeine consumers. A double-blind, crossover, placebo-controlled study involving 30 resistance-trained men (age 21.7 ± 4.1) was conducted to assess the impact of caffeine supplementation on serum growth hormone (GH) and testosterone (TS) levels before, immediately after, and 15 min post-RE. One hour before engaging in resistance exercise, subjects were randomly administered 6 mg of caffeine per kg of body mass or a placebo (maltodextrin). After a 7-day washout period, the same protocol was repeated. Resting testosterone and growth hormone levels were examined in the sera of 94 elite athletes (31 females, age 21.4 ± 2.8; 63 males, age 22.9 ± 3.8). Caffeine consumption led to significantly greater increases in GH and TS in men with the TT genotype compared to C allele carriers. Furthermore, in the group of athletes, carriers of the TT genotype had significantly higher testosterone (p = 0.0125) and growth hormone (p = 0.0365) levels compared to C allele carriers. In conclusion, the ADORA2A gene rs5751876 polymorphism may modify the effect of caffeine intake on the hormonal response to exercise.

Physical exercise as a modulator of the purinergic system in the control of sarcopenia in individuals with chronic kidney disease on hemodialysis

The word sarcopenia derives from the Greek terms "sarx" for meat and "penia" for loss, thus being used to define reductions in muscle mass, muscle strength, and lower physical performance that compromise, mainly, the elderly population. Its high negative impact on patients' quality of life encourages the production and publication of new studies that seek to find methods to prevent and reverse cases of loss of muscle mass and strength. Furthermore, the high prevalence of sarcopenia in patients with chronic kidney disease (CKD) is closely related to its pathophysiology, which consists of a state of increased protein catabolism and decreased muscle tissue synthesis. Also considering the inflammatory nature of CKD and sarcopenia, the purinergic system has been an important target of studies, which seek to relate it to the two previous conditions. This system achieves anti-inflammatory action by inhibiting, through adenosine, pro-inflammatory factors such as interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-α), and nitric oxide (NO), as well as by releasing anti-inflammatory substances such as interleukin-10 (IL-10). Simultaneously, the purinergic system presents pro-inflammatory activity, signaled by adenosine triphosphate (ATP), which occurs through the activation of T cells and the release of pro-inflammatory factors such as those mentioned above. Therefore, the ability of this system to act on inflammatory processes can promote positive and negative changes in the clinical aspect of patients with CKD and/or sarcopenia. Furthermore, it appears that there is a correlation between the practice of repeated physical exercise with the clinical improvement and in the quality of life of these patients, presenting a decrease in the levels of C-reactive protein (CRP), NTPDase, and the pro-inflammatory cytokine IL-6, such as increases in IL-10 resulting from modulation of the purinergic system. In this way, the present article seeks to evaluate the effect of physical exercise as a modulator of the purinergic system in the control of sarcopenia in patients with CKD on hemodialysis, in order to trace a relationship that can bring benefits both for biological markers and for quality of life of these patients.

Optimizing Short Sprint Interval Training for Young Soccer Players: Unveiling Optimal Rest Distributions to Maximize Physiological Adaptations

Present study aimed to compare the effects of SSIT intervention with varying rest distributions on hormonal, physiological, and performance adaptations in soccer players. Thirty-six players were randomly divided into three SSIT groups, each performing 4 sets of 6-10 repetitions of 6-second all-out running with rest intervals at ratios of 1:3, 1:6, and 1:9. Prior to and following the 7-week training period, aerobic fitness indices and anaerobic power were evaluated using a graded exercise test with a gas collection system and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring vertical jump, 20-m sprint, and T-test change of direction speed, Yo-Yo IR1 and maximal kicking distance. Hormonal status was also monitored by evaluating testosterone and cortisol levels. Following the 7-week training period, all SSIT interventions resulted in significant enhancements (p < 0.05) in soccer-related performance, physiological parameters, and hormonal adaptations, exhibiting effect sizes that ranged from small to large. Comparative analysis indicated that the 1:9 SSIT results in greater adaptive responses (p < 0.05) in the vertical jump, peak power, testosterone, and cortisol compared to the 1:3 SSIT group. By contrast, the 1:3 SSIT group induced more adaptive responses (p < 0.05) in the mean power output, maximum oxygen consumption (V̇O2max), and Yo-Yo IR1 compared to the 1:9 SSIT group. Hence, for enhancing physical performance, especially vertical jump height, anaerobic peak power, and hormonal adaptations, the 1:9 SSIT ratio is preferable. Conversely, shorter rest intervals (specifically, the 1:3 SSIT ratio) are better suited for eliciting heightened adaptive responses in mean power output, V̇O2max, and Yo-Yo IR1 over the 7-week training period among young male soccer players.

Load-Velocity Profiles Before and After Heated Resistance Exercise

ABSTRACT

Sweet, DK, Qiao, J, Rosbrook, P, and Pryor, JL. Load-velocity profiles before and after heated resistance exercise. J Strength Cond Res 38(6): 1019-1024, 2024-This study examined neuromuscular performance using load-velocity (L-V) profiles in men and women before and after resistance exercise (RE) in hot (HOT; 40° C) and temperate (TEMP; 21° C) environments. Sixteen (f = 8, m = 8) resistance-trained individuals completed a single 70-minute whole-body high-volume load (6 exercises, 4 sets of 10 repetitions) RE bout in HOT and TEMP. Before and after RE, rectal temperature (TRE), muscle temperature of the vastus lateralis (TVL) and triceps brachii (TTB), and an L-V profile for the deadlift and bench press were recorded. Thermoregulatory and L-V data were analyzed using separate 2-way repeated measures analysis of variances (ANOVAs; condition [hot, temperate] and time [pre, post]) with significance level set at p ≤ 0.05. Deadlift peak velocity was reduced at 60% 1 repetition maximum (1RM) after RE in HOT but not TEMP. Peak velocity of 40% 1RM bench press was lower in TEMP vs. HOT pre-RE (p < 0.01). Peak velocity was decreased at all loads in the deadlift L-V profile after RE, regardless of condition. Despite elevated TRE (TEMP; 37.58 ± 0.35, HOT; 38.20 ± 0.39° C), TVL (TEMP; 35.24 ± 0.62, HOT; 37.92 ± 0.55° C), and TTB (TEMP; 35.05 ± 0.78, HOT; 38.00 ± 0.16° C) after RE in HOT vs. TEMP (p < 0.01), RE in HOT did not broadly affect L-V profiles. This indicates heated resistance exercise can be performed with high-volume load and high ambient temperature with minimal performance impairment.

Systemic Sirtuin 1 as a Potential Target to Mediate Interactions Between Body Fat and Testosterone Concentration in Master Athletes

Evidence indicates that master athletes have higher concentration of Sirtuin 1 (Sirt1), lower body fat (BF), and greater activity of the hypothalamic-pituitary-gonadal axis in comparison to untrained peers. However, no published data have demonstrated possible mediation effect of Sirt1 in the interaction of BF and testosterone in this population. Therefore, this study compared and verified possible associations between Sirt1, BF, fat mass index (FMI), testosterone, luteinizing hormone (LH), and testosterone/luteinizing hormone (T/LH) ratio in middle-aged master athletes (n = 54; 51.22 ± 7.76 years) and control middle-aged peers (n = 21; 47.76 ± 8.47 years). Venous blood was collected for testosterone, LH, and Sirt1. BF was assessed through skinfold protocol. Although LH concentration did not differ between groups, master athletes presented higher concentration of Sirt1, testosterone, and T/LH ratio, and lower BF and FMI in relation to age-matched nonathletes. Moreover, Sirt1 correlated positively with testosterone and T/LH ratio, negatively with BF, and was not significantly correlated with LH (mediation analysis revealed the effect of BF on testosterone is mediated by Sirt1 and vice versa; R2 = .1776; p = .032). In conclusion, master athletes have higher testosterone, T/LH ratio, and Sirt1, and lower BF and FMI in relation to untrained peers. Furthermore, Sirt1 was negatively associated with BF and positively associated with testosterone and T/LH ratio. These findings suggest that increased circulating Sirt1, possibly due to the master athlete's training regimens and lifestyle, exhibits a potential mediation effect on the interaction between endocrine function and body composition.

A botanical extract blend of Mangifera indica and Sphaeranthus indicus combined with resistance exercise training improves muscle strength and endurance over exercise alone in young men: a randomized, blinded, placebo-controlled trial

Resistance exercise training (RET) is used to improve muscular strength and function. This study tested the hypothesis that RET alongside daily supplementation of a Sphaeranthus indicus and Mangifera indica extract blend (SMI) would augment bench press (BP) and leg extension (LE) strength and repetitions to failure (RTF) compared to RET alone. Ninety-nine men (age 22 ± 3) completed the trial after randomization into one of four groups: (A1) 425 mg SMI plus one RET set; (A2) 850 mg SMI plus one RET set; (P1) placebo plus one RET set; and (P2) placebo plus two RET sets. RET sets were 6-8 BP and LE repetitions at 80% of a progressive one repetition maximum (1-RM), performed 3x/week for 8 weeks. Strength and RTF were evaluated at baseline and days 14, 28, and 56 while serum values of total testosterone (TT), free testosterone (FT), and cortisol (C) values were evaluated at baseline and day 56. RET significantly (p < 0.05) increased 1-RM, RTF, and T measures above baselines regardless of group assignment, but the increases were greater in the supplemented groups. At week 8, A1 bench pressed more than P1 (71.5.5 ± 17.5 kg vs. 62.0 ± 15.3 kg, p = 0.003), while A2 pressed 13.8 ± 3.0 kg more (95% CI 5.7-21.8, p < 0.001) than P1 and 9.9 ± 13.0 kg more (95% CI 1.7-18.2, p = 0.01) than P2. Also at week 8, the mean LE 1-RM of A1 (159.4 ± 22.6 kg) and A2 (162.2 ± 22.9 kg) was greater (p < 0.05) than that of P1 (142.2 ± 25.6 kg) and P2 (146.5 ± 19.7 kg). Supplementation improved RTF, TT, and FT values over those measured in exercise alone (p < 0.05), while C levels in A2 (9.3 ± 3.8 μg/dL) were lower than P2 (11.7 ± 3.8 μg/dL, p < 0.05). Daily supplementation with SMI was well tolerated and may help optimize muscle adaptive responses to RET in men.