The MICOS Complex Regulates Mitochondrial Structure and Oxidative Stress During Age-Dependent Structural Deficits in the Kidney.

The kidney filters nutrient waste and bodily fluids from the bloodstream, in addition to secondary functions of metabolism and hormone secretion, requiring an astonishing amount of energy to maintain its functions. In kidney cells, mitochondria produce adenosine triphosphate (ATP) and help maintain kidney function. Due to aging, the efficiency of kidney functions begins to decrease. Dysfunction in mitochondria and cristae, the inner folds of mitochondria, is a hallmark of aging. Therefore, age-related kidney function decline could be due to changes in mitochondrial ultrastructure, increased reactive oxygen species (ROS), and subsequent alterations in metabolism and lipid composition. We sought to understand if there is altered mitochondrial ultrastructure, as marked by 3D morphological changes, across time in tubular kidney cells. Serial block facing-scanning electron microscope (SBF-SEM) and manual segmentation using the Amira software were used to visualize murine kidney samples during the aging process at 3 months (young) and 2 years (old). We found that 2-year mitochondria are more fragmented, compared to the 3-month, with many uniquely shaped mitochondria observed across aging, concomitant with shifts in ROS, metabolomics, and lipid homeostasis. Furthermore, we show that the mitochondrial contact site and cristae organizing system (MICOS) complex is impaired in the kidney due to aging. Disruption of the MICOS complex shows altered mitochondrial calcium uptake and calcium retention capacity, as well as generation of oxidative stress. We found significant, detrimental structural changes to aged kidney tubule mitochondria suggesting a potential mechanism underlying why kidney diseases occur more readily with age. We hypothesize that disruption in the MICOS complex further exacerbates mitochondrial dysfunction, creating a vicious cycle of mitochondrial degradation and oxidative stress, thus impacting kidney health.

Quantitative Assessment of Morphological Changes in Lipid Droplets and Lipid-Mito Interactions with Aging in Brown Adipose.

The physical characteristics of brown adipose tissue (BAT) are defined by the presence of multilocular lipid droplets (LD) within the brown adipocytes and a high abundance of iron-containing mitochondria, which give it its characteristic color. Normal mitochondrial function is, in part, regulated by organelle-to-organelle contacts. Particularly, the contact sites that mediate mitochondria-LD interactions are thought to have various physiological roles, such as the synthesis and metabolism of lipids. Aging is associated with mitochondrial dysfunction, and previous studies show that there are changes in mitochondrial structure and proteins that modulate organelle contact sites. However, how mitochondria-LD interactions change with aging has yet to be fully clarified. Therefore, we sought to define age-related changes in LD morphology and mitochondria-lipid interactions in BAT. We examined the three-dimensional morphology of mitochondria and LDs in young (3-month) and aged (2-year) murine BAT using serial block face-scanning electron microscopy and the Amira program for segmentation, analysis, and quantification. Analysis showed reductions in LD volume, area, and perimeter in aged samples compared to young samples. Additionally, we observed changes in LD appearance and type in aged samples compared to young samples. Notably, we found differences in mitochondrial interactions with LDs, which could implicate that these contacts may be important for energetics in aging. Upon further investigation, we also found changes in mitochondrial and cristae structure for mitochondria interacting with LD lipids. Overall, these data define the nature of LD morphology and organelle-organelle contacts during aging and provide insight into LD contact site changes that interconnect biogerontology and mitochondrial functionality, metabolism, and bioactivity in aged BAT.

Ablation of Sam50 is associated with fragmentation and alterations in metabolism in murine and human myotubes.

The sorting and assembly machinery (SAM) Complex is responsible for assembling ß-barrel proteins in the mitochondrial membrane. Comprising three subunits, Sam35, Sam37, and Sam50, the SAM complex connects the inner and outer mitochondrial membranes by interacting with the mitochondrial contact site and cristae organizing system complex. Sam50, in particular, stabilizes the mitochondrial intermembrane space bridging (MIB) complex, which is crucial for protein transport, respiratory chain complex assembly, and regulation of cristae integrity. While the role of Sam50 in mitochondrial structure and metabolism in skeletal muscle remains unclear, this study aims to investigate its impact. Serial block-face-scanning electron microscopy and computer-assisted 3D renderings were employed to compare mitochondrial structure and networking in Sam50-deficient myotubes from mice and humans with wild-type (WT) myotubes. Furthermore, autophagosome 3D structure was assessed in human myotubes. Mitochondrial metabolic phenotypes were assessed using Gas Chromatography-Mass Spectrometry-based metabolomics to explore differential changes in WT and Sam50-deficient myotubes. The results revealed increased mitochondrial fragmentation and autophagosome formation in Sam50-deficient myotubes compared to controls. Metabolomic analysis indicated elevated metabolism of propanoate and several amino acids, including ß-Alanine, phenylalanine, and tyrosine, along with increased amino acid and fatty acid metabolism in Sam50-deficient myotubes. Furthermore, impairment of oxidative capacity was observed upon Sam50 ablation in both murine and human myotubes, as measured with the XF24 Seahorse Analyzer. Collectively, these findings support the critical role of Sam50 in establishing and maintaining mitochondrial integrity, cristae structure, and mitochondrial metabolism. By elucidating the impact of Sam50-deficiency, this study enhances our understanding of mitochondrial function in skeletal muscle.

Methods to Utilize Pulse Wave Velocity to Measure Alterations in Cerebral and Cardiovascular Parameters.

Alzheimer's Disease (AD) is a global health issue, affecting over 6 million in the United States, with that number expected to increase as the aging population grows. As a neurodegenerative disorder that affects memory and cognitive functions, it is well established that AD is associated with cardiovascular risk factors beyond only cerebral decline. However, the study of cerebrovascular techniques for AD is still evolving. Here, we provide reproducible methods to measure impedance-based pulse wave velocity (PWV), a marker of arterial stiffness, in the systemic vascular (aortic PWV) and in the cerebral vascular (cerebral PWV) systems. Using aortic impedance and this relatively novel technique of cerebral impedance to comprehensively describe the systemic vascular and the cerebral vascular systems, we examined the sex-dependent differences in 5x transgenic mice (5XFAD) with AD under normal and high-fat diet, and in wild-type mice under a normal diet. Additionally, we validated our method for measuring cerebrovascular impedance in a model of induced stress in 5XFAD. Together, our results show that sex and diet differences in wildtype and 5XFAD mice account for very minimal differences in cerebral impedance. Interestingly, 5XFAD, and not wildtype, male mice on a chow diet show higher cerebral impedance, suggesting pathological differences. Opposingly, when we subjected 5XFAD mice to stress, we found that females showed elevated cerebral impedance. Using this validated method of measuring impedance-based aortic and cerebral PWV, future research may explore the effects of modifying factors including age, chronic diet, and acute stress, which may mediate cardiovascular risk in AD.

3D Mitochondrial Structure in Aging Human Skeletal Muscle: Insights into MFN-2 Mediated Changes.

Age-related atrophy of skeletal muscle, is characterized by loss of mass, strength, endurance, and oxidative capacity during aging. Notably, bioenergetics and protein turnover studies have shown that mitochondria mediate this decline in function. Although exercise has been the only therapy to mitigate sarcopenia, the mechanisms that govern how exercise serves to promote healthy muscle aging are unclear. Mitochondrial aging is associated with decreased mitochondrial capacity, so we sought to investigate how aging affects mitochondrial structure and potential age-related regulators. Specifically, the three-dimensional (3D) mitochondrial structure associated with morphological changes in skeletal muscle during aging requires further elucidation. We hypothesized that aging causes structural remodeling of mitochondrial 3D architecture representative of dysfunction, and this effect is mitigated by exercise. We used serial block-face scanning electron microscopy to image human skeletal tissue samples, followed by manual contour tracing using Amira software for 3D reconstruction and subsequent analysis of mitochondria. We then applied a rigorous in vitro and in vivo exercise regimen during aging. Across 5 human cohorts, we correlate differences in magnetic resonance imaging, mitochondria 3D structure, exercise parameters, and plasma immune markers between young (under 50 years) and old (over 50 years) individuals. We found that mitochondria we less spherical and more complex, indicating age-related declines in contact site capacity. Additionally, aged samples showed a larger volume phenotype in both female and male humans, indicating potential mitochondrial swelling. Concomitantly, muscle area, exercise capacity, and mitochondrial dynamic proteins showed age-related losses. Exercise stimulation restored mitofusin 2 (MFN2), one such of these mitochondrial dynamic proteins, which we show is required for the integrity of mitochondrial structure. Furthermore, we show that this pathway is evolutionarily conserved as Marf, the MFN2 ortholog in Drosophila, knockdown alters mitochondrial morphology and leads to the downregulation of genes regulating mitochondrial processes. Our results define age-related structural changes in mitochondria and further suggest that exercise may mitigate age-related structural decline through modulation of mitofusin 2.

A workshop to showcase the diversity of scientists to middle school students.

Identity matters in science, technology, engineering, mathematics, and medicine (STEMM) because it can affect an individual's long-term sense of belonging, which may in turn affect their persistence in STEMM. Early K-12 science classes often teach students about the foundational discoveries of the field, which have been predominately made, or at least published, by White men. This homogeneity can leave underrepresented individuals in STEMM feeling isolated, and underrepresented K-12 students may feel as though they cannot enter STEMM fields. This study aimed to examine these feelings of inclusivity in STEMM through an interactive workshop that asked middle schoolers to identify scientists from images of individuals with various racial and gender identities. We found that a plurality of students had a positive experience discussing diversity in science and recognizing underrepresented individuals as scientists.NEW & NOTEWORTHY We observed positive sentiments from middle school students following a workshop that showcased diversity in science. This workshop uniquely encourages students to recognize that physiologists and scientists today are much more diverse than textbooks typically demonstrate and can be adapted for middle schoolers, high schoolers, and college students.

Defining Mitochondrial Cristae Morphology Changes Induced by Aging in Brown Adipose Tissue.

Mitochondria are required for energy production and even give brown adipose tissue (BAT) its characteristic color due to their high iron content and abundance. The physiological function and bioenergetic capacity of mitochondria are connected to the structure, folding, and organization of its inner-membrane cristae. During the aging process, mitochondrial dysfunction is observed, and the regulatory balance of mitochondrial dynamics is often disrupted, leading to increased mitochondrial fragmentation in aging cells. Therefore, it is hypothesized that significant morphological changes in BAT mitochondria and cristae will be present with aging. A quantitative 3D electron microscopy approach is developed to map cristae network organization in mouse BAT to test this hypothesis. Using this methodology, the 3D morphology of mitochondrial cristae is investigated in adult (3-month) and aged (2-year) murine BAT tissue via serial block face-scanning electron microscopy (SBF-SEM) and 3D reconstruction software for manual segmentation, analysis, and quantification. Upon investigation, an increase is found in mitochondrial volume, surface area, and complexity and decreased sphericity in aged BAT, alongside significant decreases in cristae volume, area, perimeter, and score. Overall, these data define the nature of the mitochondrial structure in murine BAT across aging.

A quick guide to networking for scientists.

Networking is an important skill for finding social relationships relevant to one's career. However, networking can be difficult to navigate as different social situations and career levels require unique skill sets. Here, we provide tips for effective networking at conferences, dinners, and other events.

3D reconstruction of murine mitochondria reveals changes in structure during aging linked to the MICOS complex.

During aging, muscle gradually undergoes sarcopenia, the loss of function associated with loss of mass, strength, endurance, and oxidative capacity. However, the 3D structural alterations of mitochondria associated with aging in skeletal muscle and cardiac tissues are not well described. Although mitochondrial aging is associated with decreased mitochondrial capacity, the genes responsible for the morphological changes in mitochondria during aging are poorly characterized. We measured changes in mitochondrial morphology in aged murine gastrocnemius, soleus, and cardiac tissues using serial block-face scanning electron microscopy and 3D reconstructions. We also used reverse transcriptase-quantitative PCR, transmission electron microscopy quantification, Seahorse analysis, and metabolomics and lipidomics to measure changes in mitochondrial morphology and function after loss of mitochondria contact site and cristae organizing system (MICOS) complex genes, Chchd3, Chchd6, and Mitofilin. We identified significant changes in mitochondrial size in aged murine gastrocnemius, soleus, and cardiac tissues. We found that both age-related loss of the MICOS complex and knockouts of MICOS genes in mice altered mitochondrial morphology. Given the critical role of mitochondria in maintaining cellular metabolism, we characterized the metabolomes and lipidomes of young and aged mouse tissues, which showed profound alterations consistent with changes in membrane integrity, supporting our observations of age-related changes in muscle tissues. We found a relationship between changes in the MICOS complex and aging. Thus, it is important to understand the mechanisms that underlie the tissue-dependent 3D mitochondrial phenotypic changes that occur in aging and the evolutionary conservation of these mechanisms between Drosophila and mammals.

Diversity, Equity and Inclusion in the Laboratory: Strategies to Enhance Inclusive Laboratory Culture.

Building a diverse laboratory that is equitable is critical for the retention of talent and the growth of trainees professionally and personally. Here, we outline several strategies including enhancing understanding of cultural competency and humility, establishing laboratory values, and developing equitable laboratory structures to create an inclusive laboratory environment to enable trainees to achieve their highest success.

A workshop on mitochondria for students to improve understanding of science and hypothesis forming.

There remains a clear deficiency in recruiting middle school students in science, technology, engineering, mathematics, and medicine fields, especially for those students entering physiology from underrepresented backgrounds. A large part of this may be arising from a disconnect between how science is typically practiced at a collegiate and K-12 level. Here, we have envisioned mitochondria and their diverse subcellular structures as an involver for middle school students. We present the framework for a workshop that familiarizes students with mitochondria, employing three-dimensional visual-spatial learning and real-time critical thinking and hypothesis forming. This workshop had the goal of familiarizing middle school students with the unique challenges the field currently faces and better understanding the actuality of being a scientist through critical analysis including hypothesis forming. Findings show that middle school students responded positively to the program and felt as though they had a better understanding of mitochondria. Future implications for hands-on programs to involve underrepresented students in science are discussed, as well as potential considerations to adapt it for high school and undergraduate students.NEW & NOTEWORTHY Here we employ a workshop that utilizes blended and tactile learning to teach middle schoolers about mitochondrial structure. By creating an approachable and fun workshop that can be utilized for middle school students, we seek to encourage them to join a career in physiology.

Defining Mitochondrial Cristae Morphology Changes Induced by Aging in Brown Adipose Tissue.

Mitochondria are required for energy production and even give brown adipose tissue (BAT) its characteristic color due to their high iron content and abundance. The physiological function and bioenergetic capacity of mitochondria are connected to the structure, folding, and organization of its inner-membrane cristae. During the aging process, mitochondrial dysfunction is observed, and the regulatory balance of mitochondrial dynamics is often disrupted, leading to increased mitochondrial fragmentation in aging cells. Therefore, we hypothesized that significant morphological changes in BAT mitochondria and cristae would be present with aging. We developed a quantitative three-dimensional (3D) electron microscopy approach to map cristae network organization in mouse BAT to test this hypothesis. Using this methodology, we investigated the 3D morphology of mitochondrial cristae in adult (3-month) and aged (2-year) murine BAT tissue via serial block face-scanning electron microscopy (SBF-SEM) and 3D reconstruction software for manual segmentation, analysis, and quantification. Upon investigation, we found increases in mitochondrial volume, surface area, and complexity and decreased sphericity in aged BAT, alongside significant decreases in cristae volume, area, perimeter, and score. Overall, these data define the nature of the mitochondrial structure in murine BAT across aging.

Ablation of Sam50 is associated with fragmentation and alterations in metabolism in murine and human myotubes.

The Sorting and Assembly Machinery (SAM) Complex is responsible for assembling ß-barrel proteins in the mitochondrial membrane. Comprising three subunits, Sam35, Sam37, and Sam50, the SAM complex connects the inner and outer mitochondrial membranes by interacting with the mitochondrial contact site and cristae organizing system (MICOS) complex. Sam50, in particular, stabilizes the mitochondrial intermembrane space bridging (MIB) complex, which is crucial for protein transport, respiratory chain complex assembly, and regulation of cristae integrity. While the role of Sam50 in mitochondrial structure and metabolism in skeletal muscle remains unclear, this study aims to investigate its impact. Serial block-face-scanning electron microscopy (SBF-SEM) and computer-assisted 3D renderings were employed to compare mitochondrial structure and networking in Sam50-deficient myotubes from mice and humans with wild-type (WT) myotubes. Furthermore, autophagosome 3D structure was assessed in human myotubes. Mitochondrial metabolic phenotypes were assessed using Gas Chromatography-Mass Spectrometry-based metabolomics to explore differential changes in WT and Sam50-deficient myotubes. The results revealed increased mitochondrial fragmentation and autophagosome formation in Sam50-deficient myotubes compared to controls. Metabolomic analysis indicated elevated metabolism of propanoate and several amino acids, including ß-Alanine, phenylalanine, and tyrosine, along with increased amino acid and fatty acid metabolism in Sam50-deficient myotubes. Furthermore, impairment of oxidative capacity was observed upon Sam50 ablation in both murine and human myotubes, as measured with the XF24 Seahorse Analyzer. Collectively, these findings support the critical role of Sam50 in establishing and maintaining mitochondrial integrity, cristae structure, and mitochondrial metabolism. By elucidating the impact of Sam50-deficiency, this study enhances our understanding of mitochondrial function in skeletal muscle.

Serial Block Face-Scanning Electron Microscopy as a Burgeoning Technology.

Serial block face scanning electron microscopy (SBF-SEM), also referred to as serial block-face electron microscopy, is an advanced ultrastructural imaging technique that enables three-dimensional visualization that provides largerx- and y-axis ranges than other volumetric EM techniques. While SEM is first introduced in the 1930s, SBF-SEM is developed as a novel method to resolve the 3D architecture of neuronal networks across large volumes with nanometer resolution by Denk and Horstmann in 2004. Here, the authors provide an accessible overview of the advantages and challenges associated with SBF-SEM. Beyond this, the applications of SBF-SEM in biochemical domains as well as potential future clinical applications are briefly reviewed. Finally, the alternative forms of artificial intelligence-based segmentation which may contribute to devising a feasible workflow involving SBF-SEM, are also considered.

HIIT is most effective than mict on glycemic control of older people with glucose metabolism impairments: A systematic review and metanalysis.

INTRODUCTION: Physical exercise can improve glucose metabolism; however, the best type, volume, intensity, and frequency aren't knowledge. High-Intensity Interval Training (HIIT), an emergent exercise type implicated as a short time-efficient exercise to improve metabolic health, needs more investigation regarding the traditional Moderate-Intensity Continuous Training (MICT). OBJECTIVE: To identify the effects of MICT and HIIT on glycemic control of older people with glucose metabolism impairments. METHODS: Our research question was based on the PICO model and the systematic review of the literature according to the guidelines of the preferred report items for systematic reviews and PRISMA meta-analyses. An extensive search was conducted in the Web of Science, PubMed, and Scielo databases. Only English language papers were included. The keywords used were "HIIT and metabolism of the elderly", "HIIT and glucose metabolism of the elderly", and "MICT and metabolism of the elderly", which were crossed with the Boolean operators "AND" and "OR" or both according to the guidelines of the PRISMA. RESULTS: Seventy papers were retrieved in the initial search. After applying all inclusions and exclusion parameters, 63 articles were excluded. In the end, six papers were classified as eligible for this study. All data categorically demonstrates that both HIIT and MICT can improve glucose metabolism with a larger effect size towards the HIIT model after the meta-analysis, pointing to HIIT as the most effective strategy. CONCLUSION: Both modalities can improve glucose metabolism in the elderly with a clear advantage for HIIT over MICT.

Acute effects of different intervals between repeated sprints on performance responses in amateur futsal athletes / Efeitos agudos de diferentes intervalos entre sprint repetidos sobre as respostas de desempenho em atletas amadores de futsal

ABSTRACT Objective: Verify the influence of different break times between sprints on the performance of amateur futsal athletes. Methods: 10 individuals, men, amateur futsal athletes (Age: 21.5 ± 1.6; Weight: 72.4 ± 6.88; Height: 1.72 ± 0.05; BMI: 24.3 ± 1.2; Fat%: 13.7 ± 3.3, VO2peak: 49.1 ± 10.5) participated in the study. Individuals were randomly selected to perform sessions with sprints (10 sets 20 m) with different pause times of 15 (S15), 30 (S30) and 60 (S60) seconds. For performance analysis, the speed (km / h) applied to each sprint was used and monitored by a device with a photocell (CEFISE Biotecnologia Esportiva®). Results: There was an interaction between speed and interval time (p = 0.000). For condition S15, a greater reduction in performance was observed (p ≤ 0.05), while for S30 and S60, no significant reduction in performance was observed (p > 0.05). The data for the area under the curve showed a significant difference (p = 0.000), where the interval of 60 s (S60) was longer compared to the values of 30 (S30) (p = 0.000) and 15 s (S15) (p = 0.000). However, there were no significant differences between the 30 and 15 s data (p = 0.248). Conclusion: A shorter time (15 s) interval between repeated sprints can significantly affect performance compared to longer breaks (30 and 60 s), but all the conditions tested here can be positive for the improvement of performance, mainly in sports that demand fast and efficient motor actions such as futsal.

RESUMO Objetivo: Verificar a influência dos diferentes tempos de intervalo entre os sprints no desempenho dos atletas de futsal amadores. Métodos: 10 indivíduos, homens, atletas de futsal amadores (Idade: 21,5 ± 1,6; Peso: 72,4 ± 6,88; Altura: 1,72 ± 0,05; IMC: 24,3 ± 1,2; Gordura%: 13,7 ± 3,3, VO2peak: 49,1 ± 10,5) participou no estudo. Os indivíduos foram selecionados aleatoriamente para realizar sessões com sprints (10 conjuntos 20 m) com diferentes tempos de pausa de 15 (S15), 30 (S30) e 60 (S60) segundos. Para análise do desempenho, a velocidade (km/h) aplicada a cada sprint foi utilizada e monitorizada por um dispositivo com uma fotocélula (CEFISE Biotecnologia Esportiva®). Resultados: Houve uma interação entre velocidade e tempo de intervalo (p = 0,000). Para a condição S15, observou-se uma maior redução no desempenho (p ≤ 0,05), enquanto para S30 e S60, não se observou qualquer redução significativa no desempenho (p > 0,05). Os dados para a área sob a curva mostraram uma diferença significativa (p = 0,000), onde o intervalo de 60 s (S60) foi mais longo em comparação com os valores de 30 (S30) (p = 0,000) e 15 s (S15) (p = 0,000). No entanto, não houve diferenças significativas entre os dados de 30 e 15 s (p = 0,248). Conclusão: Um intervalo de tempo mais curto (15 s) entre sprints repetidos pode afetar significativamente o desempenho em comparação com os intervalos mais longos (30 e 60 s), mas todas as condições aqui testadas podem ser positivas para a melhoria do desempenho, principalmente nos desportos que exigem ações motoras rápidas e eficientes, tais como o futsal.

Recognizing and addressing environmental microaggressions, know-your-place aggression, peer mediocrity, and code-switching in STEMM.

Diversity, equity, and inclusion (DEI) initiatives are critical for fostering growth, innovation, and collaboration in science, technology, engineering, mathematics, and medicine (STEMM). This article focuses on four key topics that have impacted many Black individuals in STEMM: know-your-place aggression, environmental microaggressions, peer mediocrity, and code-switching. We provide a comprehensive background on these issues, discuss current statistics, and provide references that support their existence, as well as offer solutions to recognize and address these problems in the STEMM which can be expanded to all historically underrepresented individuals.

Higher Muscle Damage Triggered by Shorter Inter-Set Rest Periods in Volume-Equated Resistance Exercise.

Objectives: The aim of the manuscript was to analyze the effects of two rest periods between volume-equated resistance exercise (RE) on inflammatory responses (cytokines and leukocyte) and muscle damage. Methods: Ten trained men (26.40 ± 4.73 years, 80.71 ± 8.95 kg, and 176.03 ± 6.11 cm) voluntarily participated in training sessions consisting of five sets of 10 reps performed at 10-RM on (1) the barbell bench press followed by (2) leg press, with either 1- or 3-min rest between sets and exercises. Circulating concentrations of different biomarkers was measured before (Pre), and after 3 h (excepted for cytokines), 6, 12, and 24 h from exercise. The rate of perceived exertion (RPE) was recorded after each set on both planned visits. Results: We found greater increases triggered by the 1-min rest period in Creatine Kinase (CK), occurring from 12 to 24 h post-exercise compared to the 3-min rest condition. A significant increase in the 1-min rest condition was also observed in the total number of leukocytes, neutrophils, and monocytes. The 1-min rest period also triggered increases compared to baseline in pro-inflammatory cytokines [Interleukin 1 beta (IL-1ß), p = 0.004; tumor necrosis factor α (TNF-α), p = 0.01; and granulocyte-macrophage colony-stimulating factor (GM-CSF), p = 0.01], which were more evident after 6 and 12 h post-exercise. Similarly, increases in anti-inflammatory cytokines [Interleukin 5 (IL-5), p = 0.01; Interleukin 6 (IL-6), p = 0.01; and Interleukin 10 (IL-10), p = 0.01] at all time-points were observed. Conclusion: Our results indicate that a 1-min rest condition in volume-equated RE promoted greater overall muscle tissue damage with a longer duration of the inflammatory processes compared to a 3-min rest.

Acute Hormone Responses Subsequent to Agonist-Antagonist Paired Set vs. Traditional Straight Set Resistance Training.

Miranda, H, de Souza, JAAA, Scudese, E, Paz, GA, Salerno, VP, Vigário, PdS, and Willardson, JM. Acute hormone responses subsequent to agonist-antagonist paired set vs. traditional straight set resistance training. J Strength Cond Res 34(6): 1591-1599, 2020-The purpose of this study was to compare acute hormone responses and rating of perceived exertion (OMNI-Res) subsequent to the agonist-antagonist paired set (PS) vs. the traditional straight set (TS) resistance training method. Twelve recreationally trained men (25.7 ± 4.7 years, 173 ± 6.3 cm and 71.5 ± 6.6 kg) participated in the current study. After 10 repetition maximum (RM) load determination, each subject performed the following 2 experimental sessions in random order: TS session-3 sets of 10 repetitions at 85% of 10RM for the machine seated row and barbell bench press with 2-minute rest intervals between sets; and PS-3 sets of 10 repetitions with 85% of 10RM alternating machine seated row and barbell bench press for the total of 6 PSs with 2-minute rest intervals between sets. Total testosterone (TT), free testosterone (FT), cortisol, TT/cortisol ratio, growth hormone (GH), and blood lactate concentrations were measured before workout and immediately after workout and 15 and 30 minutes after workout. The OMNI-RES was recorded at the end of each set for both exercises within each session. Under the TS session, TT significantly increased immediately post-workout vs. the pre-workout time point. For the PS session, TT significantly decreased at 30-minute post-workout vs. the immediate post-workout time point, whereas, FT significantly increased immediately post-workout and 15-minute post-workout vs. the pre-workout time point. For the TS session, GH significantly increased immediately post-workout, and at the 15- and 30-minute post-workout time points vs. the pre-workout time point, respectively. For the PS session, GH was significantly increased immediately post-workout vs. the pre-workout time point. Blood lactate significantly increased at all post-workout time points vs. the pre-workout time point under both sessions. The cortisol and TT/cortisol ratio showed no differences between sessions. In conclusion, from an acute standpoint, the TS approach showed a tendency to cause greater disruption in hormone levels, despite the lack of significant differences vs. the PS approach at all time points. However, both strategies may promote similar acute hormone responses.

Sodium bicarbonate supplementation in resistance exercise performance, perceived exertion and blood lactate concentration

Aim: The aim was to evaluate the effect of sodium bicarbonate supplementation (NaHCO3) in repetition performance, perceived exertion and blood lactate concentration. Methods: Fourteen trained men (25.14 ± 3.5 years; 85.83 ± 10.18 kg; 1.78 ± 0.06 m; 26.88 ± 3.17 kg/m2) realized two upper-body resistance exercise sessions consisting of 15-RM load and 1 minute of the interval, combining bicarbonate supplementation (BS) or Placebo conditions. Results: After the ANOVA analysis, no difference was found on the total number of repetitions during the session on both BS and Placebo condition (p = 0.11). However, a greater number of total of repetitions on the machine chest fly exercise for BS vs. Placebo condition (p = 0.04) was observed. The perceived exertion increased regardless of the supplementation condition (p < 0.0001). Additionally, for the blood lactate was observed significant increases in BS vs. Placebo condition in the post verification (p = 0.013), corroborated for a bigger area under the curve (AUC) on the BS compared to Placebo (p = 0.026) condition. Conclusion: In conclusion, sodium bicarbonate supplementation was not able to improve performance during a resistance exercise session, except for the single-joint exercise performed with high values of perceived exertion, not altering the perceived exertion, and blood lactate between protocols.(AU)