Effect of testosterone on muscle and muscle protein synthesis

Pre-Competition Body Weight, Hydration, and Stress Hormone Changes Among Wrestlers

Article

Full-text available

Dec 2023

Reducing pre-competition body weight in wrestlers is a widely used method. However, losing weight fast in a short time influences athletes' hydration levels, electrolyte levels, and stress status negatively. The purpose of the study was to determine wrestlers' pre-competition body weights, hydration and electrolyte levels, and stress hormone changes. The study sample was composed of 24 young male wrestlers. Wrestlers' pre-tests were performed 20 days before the competition and post-tests were performed at competition weighing-time. With tests, wrestlers' body weights and heights were measured. Also, with the help of the specialists, 5 cc. of blood samples were drawn from the forearm veins of the participant wrestlers. According to plasma osmolarity (POsm) levels of the wrestlers, their hydration status was evaluated. Also, analyses were made for potassium, calcium, chloride, magnesium, and iron electrolyte levels as well as stress hormones such as cortisol, prolactin, total testosterone, and insulin hormone. For the analyses of the data; descriptive statistics and the Wilcoxon Rank test were employed. The correlation between plasma osmolarity and hormones was assessed using the Spearman correlation coefficient. There were significant differences between wrestlers' pre-test and post-test measurements in terms of body weights, plasma osmolarity, cortisol, prolactin, total testosterone, sodium, potassium, chloride, iron, and magnesium values. It was identified that during pre-competition wrestlers' body weights reduced by 3.96% and they became exposed to dehydration, their cortisol and prolactin hormones increased but their total testosterone decreased.

Lowering the percent body fat in the obese population might reduce male lower urinary tract symptoms

Article

Full-text available

Apr 2023
WORLD J UROL

Purpose This study aimed to investigate the practicality of percent body fat (PBF), calculated using bioelectrical impedance analysis (BIA), in predicting benign prostatic hyperplasia/lower urinary tract symptoms (BPH/LUTS). Methods This study included 844 men who underwent medical checkups at our institution between 2014 and 2022. Demographic characteristics, serum PSA levels, and prostate volume were collected using TRUS. BPH was defined as a prostate volume ≥ 30 cc. Subjects were divided into two groups according to their quartiles of PBF: the normal PBF group (first to third quartile; PBF < 27.9%) and the high PBF group (fourth quartile; PBF ≥ 27.9%). Characteristics between the groups were compared using the chi-square test and Student’s t-test. Multivariate logistic regression analysis was performed to evaluate risk factors for BPH and severe LUTS. Results The prostate volume (25.21 ± 8.4 vs 27.30 ± 9.0, p = 0.005) and percentage of BPH (22.9% vs. 32.1%, p = 0.007) were greater in the high PBF group. After multivariate analysis, old age (OR = 1.066, p < 0.001), higher appendicular skeletal muscle mass index (ASMI) (OR = 1.544, p = 0.001), and PBF ≥ 27.9% (OR = 1.455, p = 0.037) were risk factors for BPH. Larger prostate volume (OR = 1.035, p = 0.002) and PBF ≥ 27.9% (OR = 1.715, p = 0.025) were risk factors for severe LUTS. However, a greater ASMI had a protective effect against severe LUTS (OR = 0.654, p = 0.011). Conclusions This study shows that PBF and ASMI are useful for predicting BPH/LUTS. We suggest that lowering PBF to the normal range in a population with high PBF might prevent BPH, while lowering PBF and maintaining adequate ASMI could lower LUTS.

Does Dihydrotestosterone Affect Physical Performance, Or Parameters Known To Affect Physical Performance Capacity Independently From The Effect Of Testosterone?: A Protocol For A Systematic Review.

Preprint

Full-text available

Jul 2024

Prevention of Male Late-Onset Hypogonadism by Natural Polyphenolic Antioxidants

Article

Full-text available

Jun 2024

Androgen production primarily occurs in Leydig cells located in the interstitial compartment of the testis. In aging males, testosterone is crucial for maintaining muscle mass and strength, bone density, sexual function, metabolic health, energy levels, cognitive function, as well as overall well-being. As men age, testosterone production by Leydig cells of the testes begins to decline at a rate of approximately 1% per year starting from their 30s. This review highlights recent findings concerning the use of natural polyphenolics compounds, such as flavonoids, resveratrol, and phenolic acids, to enhance testosterone production, thereby preventing age-related degenerative conditions associated with testosterone insufficiency. Interestingly, most of the natural polyphenolic antioxidants having beneficial effects on testosterone production tend to enhance the expression of the steroidogenic acute regulatory protein (Star) gene in Leydig cells. The STAR protein facilitates the entry of the steroid precursor cholesterol inside mitochondria, a rate-limiting step for androgen biosynthesis. Natural polyphenolic compounds can also improve the activities of steroidogenic enzymes, hypothalamus-pituitary gland axis signaling, and testosterone bioavailability. Thus, many polyphenolic compounds such as luteolin, quercetin, resveratrol, ferulic acid phenethyl ester or gigantol may be promising in delaying the initiation of late-onset hypogonadism accompanying aging in males.

Protein Supplements with Short Peptides Are Better than Complex Protein-Based Supplements on Improving Early Fat-Free Mass Loss Following Bariatric Surgery: A Retrospective Cohort Study

Article

Full-text available

Mar 2024
OBES SURG

Introduction Bariatric surgery (BS) patients are advised to consume protein supplements to prevent fat-free mass (FFM) loss. However, limited research has explored the efficacy of diverse protein presentations on FFM preservation. This study assesses if short peptide-based (SPB) supplements surpass complex protein-based (CPB) supplements in reducing early FFM loss post-surgery. Methods In this retrospective cohort study, 138 patients who underwent BS other than Roux-en-Y-gastric bypass (RYGB) between January 2021 and March 2021 at the Department of Bariatric Surgery of the Third People’s Hospital of Chengdu were included for analysis. Patients were divided into two groups based on their consumption of protein supplements after surgery: SPB group and CPB group. Multiple linear regressions separated by sex were employed to examine the associations between SPB supplements and FFM loss and percentage of FFM (%FFM) loss, respectively. Results Among participants, 69.6% were female, with a mean age of 33.3 years. In multiple linear regression analyses, SPB supplements were significantly and positively associated with a lower FFM loss in both female (ꞵ = − 1.14, P = 0.047) and male (ꞵ = − 2.36, P = 0.024), and were positively associated with a lower %FFM loss in both female (ꞵ = − 1.83) and male (ꞵ = − 2.26) but only significant in male (P = 0.049). Conclusion SPB supplements may be more effective in preventing early FFM loss after BS, compared to CPB supplements, particularly among male patients. Therefore, SPB supplements may be recommended to patients undergoing BS. Further research is needed to validate these findings. Graphical Abstract

Lean muscle mass, not aggression, mediates a link between dominance rank and testosterone in wild male chimpanzees

Article

Jul 2023
ANIM BEHAV

Testosterone promotes mating effort, which involves intraspecific aggression for males of many species. Therefore, males with higher testosterone levels are often thought to be more aggressive. For mammals living in multimale groups, aggression is hypothesized to link male social status (i.e. dominance rank) and testosterone levels, given that high status predicts mating success and is acquired partly through aggressive intragroup competition. In male chimpanzees, Pan troglodytes, dominance rank has been repeatedly linked to interindividual variation in testosterone levels, but evidence directly linking interindividual variation in testosterone and aggression is lacking. In the present study, we test both aggression levels and lean muscle mass, as measured by urinary creatinine, as links between dominance rank and testosterone levels in a large sample of wild male chimpanzees. Multivariate analyses indicated that dominance rank was positively associated with total rates of intragroup aggression, average urinary testosterone levels and average urinary creatinine levels. Testosterone was positively associated with creatinine levels but negatively associated with total aggression rates. Furthermore, mediation analyses showed that testosterone levels facilitated an association between dominance rank and creatinine levels. Our results indicate that (1) adult male chimpanzees with higher average testosterone levels are often higher ranking but not more aggressive than males with lower testosterone and (2) lean muscle mass links dominance rank and testosterone levels in Ngogo males. We assert that aggression rates are insufficient to explain links between dominance rank and testosterone levels in male chimpanzees and that other social variables (e.g. male-male relationship quality) may regulate testosterone's links to aggression.

Oral 3‐hydroxybuturate ingestion acutely lowers circulating testosterone concentrations in healthy young males

Article

Full-text available

Jun 2023
SCAND J MED SCI SPOR

Ketone bodies, such as 3‐hydroxybutyrate (3‐OHB), have been frequently used by endurance athletes, such as cyclists, to enhance performance and recovery and are recognized for their health benefits and therapeutic effects for decades. Testosterone is a potent regulator of red blood cell production. Evidence suggests that ketone bodies can increase the production of erythropoietin, which stimulates red blood cell production. Therefore, we investigated whether an acute increase in 3‐OHB levels affects testosterone levels in healthy young men. We studied six healthy, young male participants who fasted overnight and were tested twice: (i) after drinking 37.5 g of Na‐D/L‐3‐OHB dissolved in 500 mL of distilled water (KET), and (ii) after drinking 500 mL of placebo saline water (0.9% NaCl) (CTR). During the KET trial, 3‐OHB levels increased to approximately 2.5 mM. Testosterone levels decreased significantly by 20% during KET compared to 3% during CTR. A simultaneous increase in luteinizing hormone was observed in KET. We observed no changes in other adrenal androgens, such as androstenedione and 11‐keto androgens. In conclusion, an acute increase in 3‐OHB levels decreases testosterone levels. Concomitantly, an increase in luteinizing hormone was observed. This suggests that 3‐OHB may counteract some of the beneficial effects of endurance training. Further studies, involving larger sample sizes and performance outcomes, are required to fully understand this phenomenon.

Energetic costs of testosterone in two subsistence populations

Article

Jun 2023
AM J HUM BIOL

Objective: Testosterone plays a role in mediating energetic trade-offs between growth, maintenance, and reproduction. Investments in a high testosterone phenotype trade-off against other functions, particularly survival-enhancing immune function and cellular repair; thus only individuals in good condition can maintain both a high testosterone phenotype and somatic maintenance. While these effects are observed in experimental manipulations, they are difficult to demonstrate in free-living animals, particularly in humans. We hypothesize that individuals with higher testosterone will have higher energetic expenditures than those with lower testosterone. Methods: Total energetic expenditure (TEE) was quantified using doubly labeled water in n = 40 Tsimane forager-horticulturalists (50% male, 18-87 years) and n = 11 Hadza hunter-gatherers (100% male, 18-65 years), two populations living subsistence lifestyles, high levels of physical activity, and high infectious burden. Urinary testosterone, TEE, body composition, and physical activity were measured to assess potential physical and behavioral costs associated with a high testosterone phenotype. Results: Endogenous male testosterone was significantly associated with energetic expenditure, controlling for fat free mass; a one standard deviation increase in testosterone is associated with the expenditure of an additional 96-240 calories per day. Discussion: These results suggest that a high testosterone phenotype, while beneficial for male reproduction, is also energetically expensive and likely only possible to maintain in healthy males in robust condition.

Demandas energéticas de actividades de subsistencia en individuos subadultos. Contribuciones a la ecología del comportamiento humano. Energy demands of subsistence activities in subadult individuals. Contributions to the Human Behavioral Ecology.

Thesis

Full-text available

May 2022

Guillermo Zorrilla Revilla

Esta tesis doctoral responde al interés de comprender el papel de la energía en las relaciones entre el ser humano y su entorno, siendo la energía la que modela y ajusta las adaptaciones biológicas y conductuales de los organismos terrestres y, por extensión, de la especie humana. Son varios los estudios dentro de la ecología del comportamiento humano que han utilizado la energía para comprender la adaptación y la adaptabilidad humana. Dicha adaptabilidad es fruto de la flexibilidad que muestra nuestra especie, adquirida gracias a la prolongada inmadurez de Homo sapiens. Sin embargo, son menores los estudios que se han centrado en comprender cómo actúa la energía en la conducta y la biología de los individuos subadultos. Por ello, el principal interés de esta investigación es estudiar cómo afecta la energía a la puesta en marcha de diferentes actividades de subsistencia imprescindibles en los grupos de cazadores y recolectores. Concretamente, se evaluará si el inicio de la división de labores por sexo se explica en base a diferencias en el coste y la eficiencia energética de los distintos individuos. Así mismo, se valorará el papel activo y la productividad de los individuos subadultos dentro de un grupo humano, y si ello se ve limitado por cuestiones energéticas. Finalmente, se analizará si el coste de la locomoción y la velocidad óptima alcanzada por sujetos subadultos puede limitar la movilidad y la puesta en marcha de actividades que dependen de la locomoción en grupos humanos. Con todo, se tratará de conocer si la energía actúa como un limitante a la hora de aprender y desarrollar actividades complejas propias de nuestra especie y cómo afecta esto a las dinámicas energéticas del resto de individuos de un grupo humano. Para ello se han empleado datos de dos estudios experimentales, llevados a cabo en el Laboratorio de Bioenergía y Análisis del Movimiento del Centro Nacional de Investigación sobre la Evolución Humana (CENIEH). Estos corresponden a 118 voluntarios de entre 7 y 14 años de edad, y recogen diferentes medidas antropométricas, de composición corporal y de gasto energético. Los dos estudios experimentales incluían simulaciones de actividades comunes entre los individuos subadultos de ciertos grupos de cazadores y recolectores de la actualidad, como la recolección y la extracción de recursos y caminar a diferentes velocidades. Los resultados obtenidos en el conjunto de las pruebas revelan que, tanto la energía gastada, como la eficiencia en una actividad productiva, no explican la diferencia de labores entre sexos, pero tampoco entre edades si se comparan con las velocidades óptimas adultas. Se propone que la división de labores en base al sexo debe responder a otras cuestiones, relacionadas con el aprendizaje temprano en habilidades complejas específicas para cada sexo. Además, debido a la relación entre el gasto energético y el tamaño corporal en actividades productivas en las que se aprenden esas habilidades, los individuos juveniles gozan de una ventaja, ya que comienzan a aprender en una fase en la que el crecimiento corporal se retiene y se consume menos energía porque se tiene un tamaño menor. Por ello, practicar durante esta etapa, supone un ahorro en forma de energía respecto a otras fases en las que se tiene un mayor tamaño corporal y sí se invierte más energía en crecimiento y desarrollo, como en la adolescencia. Por otro lado, el gasto energético de la prueba de extracción de recursos bien se cubriría con el retorno calórico facilitado por diferentes autores, pero no podríamos confirmar que se alcancen ya tasas de productividad adulta. En esta prueba también se ha demostrado que, igual que se observa en el gasto energético del resto de actividades aquí desarrolladas, tampoco existen diferencias entre sexos en la eficiencia derivada de extraer recursos del suelo. Este resultado se ha obtenido al tener en cuenta la tasa de eficiencia (energía gastada/retorno conseguido). Respecto a las actividades que dependen de la locomoción bípeda, no existen diferencias entre sexos en la velocidad óptima, ni el gasto derivado de alcanzar esta velocidad. Por lo tanto, se propone que ambas variables no condicionarían a los individuos aquí estudiados a la hora de acompañar a un grupo adulto de cazadores y recolectores, ni durante la movilidad ni mientras se captan recursos. Por otro lado, la capacidad para alcanzar velocidades óptimas semejantes a las publicadas para individuos adultos, podría suponer a los subadultos ventajas al consumir menos energía por ser más pequeños. No obstante, en determinadas sociedades estos individuos no se involucran en ciertas actividades de manera temprana, por lo que existen otras causas, más allá de la velocidad o el gasto energético, que pueden dificultar la participación de los subadultos en algunas actividades adultas. Todas estas ventajas han podido propiciar en la especie Homo sapiens un ahorro de energía que directamente, no solo beneficia al individuo subadulto, sino también a otros individuos del grupo. Muchas de las ventajas aquí expuestas se ven acompasadas por la peculiar historia biológica humana. Por ello, otras especies de homininos que hayan requerido del aprendizaje de habilidades complejas para subsistir, se habrían beneficiado de las mismas ventajas que exponemos en esta investigación, solo si hubiesen tenido los mismos patrones de desarrollo y crecimiento encontrados en Homo sapiens. The main interest of this Ph.D. Dissertation is to understand the key-role of the energy in the relationship between humans and the environment, since energy is the factor that models and adjusts the biological and behavioural adaptations of all living organisms and, by extension, of humans too. Several studies within the Human Behavioural Ecology have used the energy to understand human adaptation and adaptability. This adaptability is the main result of human plasticity, acquired thanks to the prolonged immaturity of Homo sapiens. However, fewer studies have focused on understanding how energy affects subadult behaviour and biology. Therefore, the main interest of this research is to study how energy affects the implementation of different essential human behaviours in hunter-gatherer societies. Specifically, it will be evaluated if the onset of division of labour by sex is caused by differences in the efficiency and the energetic demands of different individuals. In addition, the active role and the productivity of non-adult individuals will be assessed, together with possible energetic limitations in this regard. Finally, the cost of locomotion and the optimal speed will be analysed to test if non-adult individuals limit group mobility or the participation in foraging activities involving locomotion. Consequently, it will be discussed if energy is a limitation while learning-by-doing complex activities, commonly practiced by Homo sapiens species, and how this affects the energetic dynamics of a human group. To achieve this, data from two experimental studies carried out in the Laboratory of Bioenergy and Analysis of the Movement of the CENIEH have been used. Data were obtained from 118 volunteers between 7 and 14 years of age, and referred to different anthropometric, body composition and energy expenditure measurements. The two experimental studies consisted of three trials, simulating common activities among subadult individuals of certain groups of current hunter-gatherers. The recreated activities were a gathering test, a digging tubers trial, and a locomotion activity at different speeds. The results obtained in all of the experimental studies reveal that the energy expended and the efficiency in a productive activity do not explain the onset of sex division of labor. It is proposed that the division of labor is caused by other questions related to the early learning in sex-specific complex skills. In addition, due to the relationship between energy expenditure and body size in some productive activities (through which non-adults learn these skills), juvenile individuals have an energetic advantage, because they decelerate the body growth in this phase and they consume less energy due to their smaller body size. Therefore, learning-by-doing at this stage promotes energy savings compared to other phases with a larger body size and a greater somatic investment, like adolescence. On the other hand, the energy expenditure of digging would be covered with the energetic return reported by other investigations, but we cannot confirm that our individuals have already achieved adult productivity rates. In this test, taking into account the results of the efficiency index (energy expended/items reported) it has also been shown that there are no differences among sexes based on the efficiency of extracting tubers from the ground, as we have observed for the energy expenditure of the rest of the activities carried out here. Regarding the locomotion test, there are no differences among sexes, or ages when compared with adult values from other studies, neither comparing the optimal walking speed, nor the energy expenditure at this speed. Thus, it is proposed that both variables are not a limitation for the individuals here studied if they would be part of a hunter-gatherer group, neither during the mobility of the group, nor while foraging. On the other hand, our volunteers reach similar optimal speeds as those reported in the literature for adult individuals. This could constitute and advantage for non-adult individuals, as they are consuming less energy because they are smaller. Nonetheless, in certain societies, non-adult individuals are not involved in some activities anyway, thus there may be other causes, beyond speed or energy costs, that can hinder the participation of non-adults in some adult activities. All the mentioned advantages would allow energy savings for Homo sapiens. This savings would directly benefit the non-adult individual, but also the rest of the group. However, most of the advantages highlighted here are linked to the peculiar Homo sapiens Life History. Therefore, the advantages we expose in this research would benefit other extinct species with subsistence complex skills, only if Homo sapiens-like development and growth patterns were already present.

Androgens, antlers, and sexual selection: testosterone’s relationship to reproductive success and associated morphological characteristics in white-tailed deer

Article

Full-text available

Nov 2022
EVOL ECOL

While hormones such as testosterone are known to drive reproduction and sexually selected traits in many species, research demonstrating a relationship between testosterone and annual or overall reproductive success is sparse. We sought to directly measure how circulating testosterone relates to sexually selected characteristics and reproductive success in a freely breeding population of white-tailed deer (Odocoileus virginanus). We captured individuals during September–March annually from 2007 to 2017 and investigated the association between testosterone and antler size, body size, and annual reproductive success for individuals. We also assessed lifetime patterns from individuals captured multiple years. We found a positive relationship between testosterone and body size, and between testosterone and antler size. However, we found a significant interaction between testosterone and age for both body size and antler size response variables, indicating that as age increases, the aforementioned positive relationships with testosterone diminish. Thus, for deer ≥ 6.5 years of age, testosterone is negatively related to body and antler size. In contrast, annual reproductive success, measured by number of offspring sired and recruited into the breeding population, was positively associated with antler size and body size, but not testosterone, age, or an interaction between testosterone and age. Instead, while an individual’s average lifetime testosterone had no relationship with overall reproductive success, greater variation in lifetime testosterone was positively related to overall reproductive success. Thus, while we found no significant association between testosterone and annual reproductive success directly, testosterone may be indirectly related to reproductive success through its positive association with antler and body size. Furthermore, understanding how testosterone may fluctuate throughout an individual’s lifetime may offer new perspectives in understanding variation in individual reproductive success.

Performance Stereotypes as a Function of Men’s Facial Formidability in the Context of Intergroup Conflict

Article

Full-text available

Oct 2024

Ascriptions of men’s physical prowess track formidability inferences, which frequently occur through the evaluations of men’s facial width-to-height ratio (fWHR). Within these ascriptions could include downstream inferences of their coalitional utility for intergroup conflict, which could manifest in modern-day contexts as expectations for men’s optimal roles in military settings. Nonetheless, despite these potential advantages, formidability may provide perceivers the basis of inferred limitations in coalitional settings, namely their intelligence. The current research tasked perceivers to evaluate the effectiveness of men in various defense-related roles as a function of their fWHR. Perceivers expected high-fWHR men to be more effective in combat than in intel roles (Study 1). The perceptions of their physical advantages persisted with concomitant knowledge of their role in combat, whereas their perceived disadvantage in intel roles was mitigated (Study 2). Low-fWHR men were further perceived as more desirable as codebreakers (Study 3). The results suggest that inferences about men’s mental abilities are more readily influenced by conflicting information than those related to formidability, thereby clarifying the pervasiveness of the latter in shaping stereotypes of men’s physical abilities.

Evaluating the effectiveness of housework as exercise for overweight and obese Filipino teenagers

Article

Full-text available

Sep 2024

Considering the concerning increase in overweight and obesity rates among Filipino youth, this study seeks to evaluate the effectiveness of a housework-based exercise program. This program capitalizes on the inherent familiarity of traditional household chores, transforming them into structured exercise routines designed to improve the physical fitness levels of overweight and obese Filipino adolescents. A one-group pretest-posttest design was employed. The intervention transformed traditional household chores into structured exercise routines. Fitness parameters, including Body Mass Index (BMI), cardiovascular endurance, flexibility, and muscular strength & endurance, were assessed before and after the intervention. Statistical analysis was conducted using SPSS software version 29, with Q-Q plots used to confirm the normality of the data. Paired sample t-tests evaluated pre- and post-intervention changes, while independent sample –t-tests determined gender differences. Findings showed that males experienced a greater reduction in BMI (+13.37%, p < .001, effect size = 1.393), while females showed more improvement in cardiovascular endurance (+8.82%, p < .001, effect size = 2.354) and flexibility (left: −46.12%, p < .001, right: −8.31%, p < .001). Both sexes achieved similar gains in muscular strength and endurance (push-up: −35.33%, p < .001, plank: −30.77%, p < .001). This research supports the value of everyday activities beyond structured exercise programs, highlighting the potential of a culturally sensitive approach that utilizes familiar household chores. The program promotes physical activity in a way that resonates with Filipino adolescents and their families, offering a promising, cost-effective intervention to address childhood obesity within the Filipino community.

Involvement of the AMPK Pathways in Muscle Development Disparities across Genders in Muscovy Ducks

Article

Full-text available

Sep 2024
INT J MOL SCI

The differences in muscle development potential between male and female ducks lead to variations in body weight, significantly affecting the growth of the Muscovy duck meat industry. The aim of this study is to explore the regulatory mechanisms for the muscle development differences between genders. Muscovy ducks of both sexes were selected for measurements of body weight, growth traits, hormone levels, and muscle gene expression. The results show that male ducks compared to females had greater weight and growth traits (P < 0.05). Compared to male ducks, the level of serum testosterone in female ducks was decreased, and the estradiol levels were increased (p < 0.05). The RNA-seq analysis identified 102 upregulated and 49 downregulated differentially expressed genes. KEGG analysis revealed that among the top 10 differentially enriched pathways, the AMPK signaling pathway is closely related to muscle growth and development. Additionally, the mRNA and protein levels of CD36, CPT1A, LPL, and SREBP1 were increased and the P-AMPK protein level decreased in the female ducks compared to the male ducks (p < 0.05). In conclusion, muscle development potential difference between male and female ducks is regulated by sex hormones. This process is likely mediated through the activation of the AMPK pathway.

Effects of Heat Stress-Induced Sex Hormone Dysregulation on Reproduction and Growth in Male Adolescents and Beneficial Foods

Article

Full-text available

Sep 2024

Seong-Hee Ko

Heat stress due to climate warming can significantly affect the synthesis of sex hormones in male adolescents, which can impair the ability of the hypothalamus to secrete gonadotropin-releasing hormone on the hypothalamic–pituitary–gonadal axis, which leads to a decrease in luteinizing hormone and follicle-stimulating hormone, which ultimately negatively affects spermatogenesis and testosterone synthesis. For optimal spermatogenesis, the testicular temperature should be 2–6 °C lower than body temperature. Heat stress directly affects the testes, damaging them and reducing testosterone synthesis. Additionally, chronic heat stress abnormally increases the level of aromatase in Leydig cells, which increases estradiol synthesis while decreasing testosterone, leading to an imbalance of sex hormones and spermatogenesis failure. Low levels of testosterone in male adolescents lead to delayed puberty and incomplete sexual maturation, negatively affect height growth and bone mineral density, and can lead to a decrease in lean body mass and an increase in fat mass. In order for male adolescents to acquire healthy reproductive capacity, it is recommended to provide sufficient nutrition and energy, avoid exposure to heat stress, and provide foods and supplements to prevent or repair testosterone reduction, germ cell damage, and sperm count reduction caused by heat stress so that they can enter a healthy adulthood.

Associations between sarcopenia and circulating branched-chain amino acids: a cross-sectional study over 100,000 participants

Article

Full-text available

Jun 2024
BMC Geriatr

Background Emerging evidence suggests that alterations in BCAA metabolism may contribute to the pathogenesis of sarcopenia. However, the relationship between branched-chain amino acids (BCAAs) and sarcopenia is incompletely understood, and existing literature presents conflicting results. In this study, we conducted a community-based study involving > 100,000 United Kingdom adults to comprehensively explore the association between BCAAs and sarcopenia, and assess the potential role of muscle mass in mediating the relationship between BCAAs and muscle strength. Methods Multivariable linear regression analysis examined the relationship between circulating BCAAs and muscle mass/strength. Logistic regression analysis assessed the impact of circulating BCAAs and quartiles of BCAAs on sarcopenia risk. Subgroup analyses explored the variations in associations across age, and gender. Mediation analysis investigated the potential mediating effect of muscle mass on the BCAA-muscle strength relationship. Results Among 108,017 participants (mean age: 56.40 ± 8.09 years; 46.23% men), positive associations were observed between total BCAA, isoleucine, leucine, valine, and muscle mass (beta, 0.56–2.53; p < 0.05) and between total BCAA, leucine, valine, and muscle strength (beta, 0.91–3.44; p < 0.05). Logistic regression analysis revealed that increased circulating valine was associated with a 47% reduced sarcopenia risk (odds ratio = 0.53; 95% confidence interval = 0.3–0.94; p = 0.029). Subgroup analyses demonstrated strong associations between circulating BCAAs and muscle mass/strength in men and individuals aged ≥ 60 years. Mediation analysis suggested that muscle mass completely mediated the relationship between total BCAA, and valine levels and muscle strength, partially mediated the relationship between leucine levels and muscle strength, obscuring the true effect of isoleucine on muscle strength. Conclusion This study suggested the potential benefits of BCAAs in preserving muscle mass/strength and highlighted muscle mass might be mediator of BCAA-muscle strength association. Our findings contribute new evidence for the clinical prevention and treatment of sarcopenia and related conditions involving muscle mass/strength loss.

Revising home advantage in sport - home advantage mediation (HAM) model

Article

Full-text available

Jun 2024
Int Rev Sport Exerc Psychol

The Home Advantage (HA) phenomenon, where teams perform better in front of their fans, has garnered increased interest during the COVID-19 pandemic, which provided a unique opportunity to study HA without crowd presence. Despite the presence of useful conceptual frameworks, most previous research has focused on investigating isolated individual factors. Here we review our newly developed Home Advantage Mediated (HAM) model, which considers all major factors and their interrelations simultaneously. HAM assumes that the crowd effects are mediated through other relevant factors, such as referee bias and team performance. Most importantly, HAM can be formally expressed as a mediation model, a technique widely employed in social sciences for investigating causal pathways. We demonstrate how researchers can use HAM to model the HA in European football and how moderating variables, such as COVID-19 and the absence of fans, can be incorporated into the model to disentangle the processes behind the HA phenomenon. This model not only sheds new light on this well-established sports phenomenon but also guides the practical application of mediation and moderated mediation models in a Bayesian framework. This approach can be extended to other sports science areas, demonstrating the versatility and utility of our model. ARTICLE HISTORY

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

Article

Full-text available

Jun 2024

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.

BREATHE DMD: boosting respiratory efficacy after therapeutic hypoxic episodes in Duchenne muscular dystrophy

Article

Full-text available

Jun 2024
J PHYSIOL-LONDON

Duchenne muscular dystrophy (DMD) is a fatal genetic neuromuscular disorder, characterised by progressive decline in skeletal muscle function due to the secondary consequences of dystrophin deficiency. Weakness extends to the respiratory musculature, and cardiorespiratory failure is the leading cause of death in men with DMD. Intermittent hypoxia has emerged as a potential therapy to counteract ventilatory insufficiency by eliciting long‐term facilitation of breathing. Mechanisms of sensory and motor facilitation of breathing have been well delineated in animal models. Various paradigms of intermittent hypoxia have been designed and implemented in human trials culminating in clinical trials in people with spinal cord injury and amyotrophic lateral sclerosis. Application of therapeutic intermittent hypoxia to DMD is considered together with discussion of the potential barriers to progression owing to the complexity of this devastating disease. Notwithstanding the considerable challenges and potential pitfalls of intermittent hypoxia‐based therapies for DMD, we suggest it is incumbent on the research community to explore the potential benefits in pre‐clinical models. Intermittent hypoxia paradigms should be implemented to explore the proclivity to express respiratory plasticity with the longer‐term aim of preserving and potentiating ventilation in pre‐clinical models and people with DMD. image

Gender Differences in Liver Steatosis and Fibrosis in Overweight and Obese Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease before and after 8 Weeks of Very Low-Calorie Ketogenic Diet

Article

Full-text available

May 2024

Obesity and metabolic syndrome are linked to steatotic liver disease (SLD), the most common form of chronic liver disease. Lifestyle modifications and dieting are strategies that can prevent metabolic dysfunction-associated steatotic liver disease (MASLD). The very low-calorie ketogenic diet (VLCKD) is a helpful treatment for MASLD and has been recommended for people affected by obesity; we evaluated the effect of gender on steatosis and fibrosis in a cohort of 112 overweight or obese patients undergoing an eight-week treatment with a VLCKD. Differences between the genders in terms of anthropometric measures, body composition, and metabolic indicators were examined before, during, and after the nutritional intervention. At baseline, there were significant differences between men and women in terms of anthropometric parameters, blood pressure, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), fasting insulin, hepatic markers, and lipid profile. Men had considerably higher levels of liver steatosis (measured by CAP) and liver stiffness (measured by E) under basal conditions than women. After the VLCKD, there were reductions in both genders of controlled attenuation parameter (CAP), body weight, body mass index (BMI), waist circumference, systolic and diastolic blood pressure, insulin resistance, fat mass (FM), free fat mass (FFM), and fasting blood glucose, insulin, glycated hemoglobin (HbA1c), triglycerides, total cholesterol, low-density lipoprotein (LDL) cholesterol, alanine transaminase (ALT), gamma-glutamyl transferase (γGT), and uric acid levels. Only in men, liver stiffness, aspartate aminotransferase (AST), creatinine, and C-reactive protein (CRP) levels significantly decreased. Moreover, men had significantly greater levels of liver steatosis: the male gender featured an increase of 23.96 points of the Fibroscan CAP. Men exhibited higher levels of steatosis and fibrosis than women, and these differences persist despite VLCKD. These gender-specific variations in steatosis and fibrosis levels could be caused by hormonal and metabolic factors, suggesting that different therapeutic strategies might be required depending on the gender.

Oral Supplementation of Dragon Power® Polygonatum had Beneficial Effects on Testosterone's Relationship with Cardiorespiratory Fitness and Erection: a Double-Blind, Placebo-Controlled Study

Article

Full-text available

Jan 2024

Chi-Fu Chiang

As age increases, the concentration of testosterone (male hormone) in the body gradually decreases, causing various aging conditions, such as physical strength. Among them, the Chinese herbal medicine Polygonatum kingianum (PK) can very well improve physical strength and resist fatigue. The purpose of this study is to explore whether PK can increase testosterone's relationship with cardiorespiratory fitness and erection. Subjects were randomly assigned to either the placebo group (n=25) or the PK group (n=25). Subjects were required to ingest 50 mL of the test product daily for a duration of 4 weeks. Cardiorespiratory endurance and blood biochemical values were analyzed at week 0, week 2, and week 4. After the subjects took it for 4 weeks, the results showed that PK extract drink increased testosterone 14% compared to the placebo group, and without any side effects on liver and kidney function. After taking PK extract drink for 2 and 4 weeks, the cardiorespiratory endurance index was significantly improved by 3.7% and 6.2%, and phosphodiesterase 5 (PDE5) expression was significantly decreased by 23.3% and 28.9% compared to placebo group. PK extract drink increased testosterone and was harmless to humans, and improved physical strength, erectile function.

Expectations of Men’s Use of Harsh Parental Discipline Through Formidability Inferences

Article

Full-text available

Mar 2024

Public Significance Statement Perceivers use men’s facial structures to estimate their behavioral intentions, particularly features diagnostic of their formidability. From these formidability inferences, people could estimate how men engage in parental behaviors, namely how they would likely discipline their children. In four experiments, participants indicated the likelihood that men would punish their children while similarly determining the basis of these inferences and what type of punishment would likely occur for formidable men. Formidable men were stereotyped as being more prone to punishing their children, a perception largely rooted in perceptions of their proclivity toward anger and specific to harsh punishments. These inferences also led perceivers to view formidable men as prone to child abuse. We discuss how modern conventions of parenting are informed by evolutionary motives and how this stereotyping can interfere with fair treatment of men.

Influence of Androgen Deprivation Therapy on the Development of Sarcopenia in Patients with Prostate Cancer: A Systematic Review

Article

Full-text available

Feb 2024

The changes in body composition during androgen deprivation therapy (ADT) in patients suffering from prostate cancer (PCa) are recognized by professionals more often as biomarker for effective treatment. The aim of this study was to investigate the impact of ADT on the sarcopenia development in PCa. The following databases were used: PubMed, Embase, Web of Science and Scopus databases. Out of 2183 studies, 7 were included in this review. The fixed-effect model was used in the meta-analysis. A significant increase in SATI (Subcutaneous Adipose Tissue Index) of 0.32 (95% CI: 0.13–0.51) p = 0.001, decrease in SMI (Skeletal Muscle Index) of −0.38 (95% CI: −0.57 to −0.19) p < 0.0001, and SMD (Skeletal Muscle Density) of −0.46 (95% CI: −0.69 to −0.24) p < 0.0001 were observed. No statistical association was visible between ADT and changes in BMI (Body Mass Index), 0.05 (95% CI: −0.18–0.28), p = 0.686, and VATI (Visceral Adipose Tissue Index): 0.17 (95% CI: −0.02 to 0.37), p = 0.074. In conclusion, the ADT significantly contributes to the body composition changes and sarcopenia development.

Dietary supplementation habits in international natural bodybuilders during pre-competition

Article

Full-text available

Feb 2024

Bodybuilding is characterized by high-rates of sport supplementation. This is the first study to compare the supplementation patterns of winners (WB) and non-winners (NWB) among international natural bodybuilders during contest preparation. Fifty-six natural bodybuilders (5 women) (age = 28.85 ± 8.03 years; final body mass = 71.50 ± 10.28 kg), 19 WB (athletes who had achieved victory in an official natural bodybuilding championship at least once) and 37 NWB (athletes who never achieved victory), from 18 countries (55.36% from Spain) responded to this cross-sectional online survey related to their nutritional habits, strategies and supplementation practices. WB were significantly older (p = 0.024), completed more competitive seasons (p = 0.027) and participated in more competitions in the last contest year (p = 0.011). There were no significant differences between WB and NWB for years training for bodybuilding (p = 0.055), weeks of dieting for competition (p = 0.392), and body weight at the start (p = 0.553) and end (p = 0.330) of the season. Beverage and supplement consumption, purchasing patterns, and information sources did not differ between groups (p > 0.05). In conclusion, natural bodybuilding WB tended to be older and had more competitive experience, but shared similar supplementation protocols to NWB. Athletes' supplementation patterns were influenced by different sources of information. However, these natural bodybuilders mainly purchased their supplements through the internet without guidance from a coach or dietitian.

Influence of Androgen Deprivation Therapy on Development of Sarcopenia in Patients with Prostate Cancer: A Systematic Review

Preprint

Full-text available

Jan 2024

The changes in body composition during androgen deprivation therapy (ADT) in patients suffer from prostate cancer (PCa) are recognized by professionals more often as key for effective treatment. The aim of this study was to investigate the impact of ADT on the sarcopenia development in PCa. The following databases were used: PubMed, Embase, Web of Science and Scopus databases. Out of 2183 studies, 7 were included in this review. The fixed-effect model was used in the meta-analysis. Significant increase in SATI: 0.32 (95%CI: 0.13-0.51) p= 0.001, de-crease in SMI: -0.38 (95% CI: -0.57 to -0.19) p < 0.0001 and SMD: -0.46 (95% CI: -0.69 to -0.24) p < 0.0001 was observed. No statistical association was visible between ADT and changes in BMI: 0.05 (95%CI: -0.18-0.28), p= 0.686 and VATI: 0.17 (95% CI: -0.02 to 0.37), p=0.074. In conclusion, the ADT significantly contributes to the body composition changes and sarcopenia development.

Resistance Exercise Training, a Simple Intervention to Preserve Muscle Mass and Strength in Prostate Cancer Patients on Androgen Deprivation Therapy

Article

Dec 2023

Androgen deprivation therapy (ADT) forms the cornerstone in the treatment of advanced prostate cancer. However, by suppressing testosterone ADT results in a decrease of skeletal muscle mass. In this narrative review, we explore the magnitude and mechanisms of ADT-induced muscle mass loss and the consequences for muscle strength and physical performance. Subsequently, we elucidate the effectiveness of supervised resistance exercise training as a means to mitigate these adverse effects. Literature shows that resistance exercise training can effectively counteract ADT-induced loss of appendicular lean body mass and decline in muscle strength, while the effect on physical performances is inconclusive. As resistance exercise training is feasible and can be safely implemented during ADT (with special attention for patients with bone metastases), it should be incorporated in standard clinical care for prostate cancer patients (starting) with ADT.

Testosterone Influences Spatial Cognition in Older Men

Article

Full-text available

Apr 1994

Testosterone plays a role in the organization of behavior during development. The authors examined whether testosterone could play a maintenance role in behavior as well. In a double-blind manner, verbal and visual memory, spatial cognition, motor speed, cognitive flexibility, and mood in a group of healthy older men who were supplemented for 3 months with testosterone were assessed. The increase in testosterone levels to 150% of baseline levels resulted in a significant enhancement of spatial cognition, but no change in any other cognitive domain was found. Testosterone supplementation influenced the endogenous production of estradiol, and estradiol was found to have an inverse relationship to spatial cognitive performance. These results suggest that testosterone supplementation can modify spatial cognition in older men; however, it is likely that this occurs through testosterone's influence on estrogen.

Recent Advances in Nutraceuticals for the Treatment of Sarcopenic Obesity

Article

Full-text available

Sep 2023

Sarcopenic obesity, low muscle mass, and high body fat are growing health concerns in the aging population. This review highlights the need for standardized criteria and explores nutraceuticals as potential therapeutic agents. Sarcopenic obesity is associated with insulin resistance, inflammation, hormonal changes, and reduced physical activity. These factors lead to impaired muscle activity, intramuscular fat accumulation, and reduced protein synthesis, resulting in muscle catabolism and increased fat mass. Myostatin and irisin are myokines that regulate muscle synthesis and energy expenditure, respectively. Nutritional supplementation with vitamin D and calcium is recommended for increasing muscle mass and reducing body fat content. Testosterone therapy decreases fat mass and improves muscle strength. Vitamin K, specifically menaquinone-4 (MK-4), improves mitochondrial function and reduces muscle damage. Irisin is a hormone secreted during exercise that enhances oxidative metabolism, prevents insulin resistance and obesity, and improves bone quality. Low-glycemic-index diets and green cardamom are potential methods for managing sarcopenic obesity. In conclusion, along with exercise and dietary support, nutraceuticals, such as vitamin D, calcium, vitamin K, and natural agonists of irisin or testosterone, can serve as promising future therapeutic alternatives.

Comparative Quality Traits, Flavor Compounds, and Metabolite Profile of Korean Native Black Goat Meat

Article

Full-text available

Jun 2023

Although goat meat has several health benefits than other red meats but comsumers reluctant it due to its unpleasant flavor. This study aimed to investigate the odorant of goat meat as well as compare the quality traits of meat regarding sex status. The loin meats [non-castrated male (NCM), castrated male (CM), and female (FM)] were collected and stored at 4oC in a laboratory refrigerator and analyzed on the 1st, 5th, and 8th consecutive days. The moisture content was the lowest and the protein content was highest in FM (p<0.05). Fat and ash content in NCM and FM were similar while lowest in CM. The L* value was significantly higher in NCM, but there was no significant differences of a* and b* values within groups at initial day. The color intensity increased on the 5th storage day and decreased again after the 8th storage day, except in NCM. NCM displayed the highest TBARS value (p<0.05), whereas CM displayed a higher pH value than other groups throughout the storage period. Indole levels were the highest in NCM (0.031 mg/kg); however, skatole levels were not significant differences across all treatments (p>0.05). No significant difference was observed in the fatty acid composition between NCM and CM (p>0.05), whereas a significant difference was observed in FM (p<0.05). Most of the water-soluble metabolites showed significant differences between sexes. Overall, sex status effects on quality properties of meat and castration can improve the overall sensory acceptance by reducing goaty flavor of Korean native black goat meat. Keywords: black goat meat; sexes; goaty flavor; water-soluble metabolites; indole

Enzymatically modified isoquercitrin in soy protein temporarily enhanced the plasma amino-acid concentrations, antioxidant index, and plasma hormone levels: a randomized, double-blind cross-over trial

Article

Full-text available

May 2023
AMINO ACIDS

This study investigated the effects of a dietary protein supplement containing enzymatically modified isoquercitrin (EMIQ) on plasma amino-acid levels in healthy people. A randomized double-blind cross-over trial (UMIN000044791) was conducted with a sample of nine healthy individuals. These participants ingested soy protein with or without 42 mg EMIQ for 7 days after performing mild exercise. Plasma amino-acid levels were measured before ingestion and at 15, 30, 45, 60, 90, 120, 180, and 240 min after ingestion on the last day. The concentrations of total amino acids at 0 and 120 min and easily oxidized amino acids at 120 min were significantly higher in the plasma of individuals who consumed 42 mg EMIQ. Oxidative stress levels were lower and plasma testosterone levels were higher in participants who ingested soy protein with 42 mg EMIQ than in those who did not. These results suggest that daily ingestion of soy protein with 42 mg EMIQ can be useful for effective protein absorption.

Is Plant Protein Equally As Effective At Promoting Lean Muscle Mass Compared To Meat?

Article

Full-text available

Mar 2023

In the past few decades, there has been an increased emphasis on plant-based diets. While plant-based diets have many cardiovascular and environmental benefits, little is known about how plant-based diets specifically impact athletic performance and promote muscle growth. Many athletes are reluctant to adopt plant-based diets, fearing that they will lose lean muscle mass due to insufficient protein content. In this research review, we evaluate factors that differentiate plant proteins and meat in regard to optimal lean muscle synthesis. One of the more important differences between plant protein and meat is their amino acid composition. Since meats contain all 9 essential and many nonessential amino acids, they have a more “well-rounded” amino acid composition, thus being more effective at promoting lean muscle growth. A protein source’s amino acid composition, along with other factors such as cell structure, affects its bioavailability. Due to differences in protein bioavailability, different quantities of distinct protein sources may need to be consumed to reach the same anabolic effect. In addition to amino acid compositions, nutrient densities also differ between plant proteins and meats. Although there are some exceptions, plant-based proteins tend to offer a more balanced profile of minerals and nutrients, which also facilitate lean muscle synthesis on the chemical level. Overall, an omnivorous diet may be optimal for muscle growth, but introducing a variety of plant proteins with different amino acid and nutritional profiles can help overcome this variance.

Titre de la thèse: Antécédents socioprofessionnels et impacts sur la force musculaire, et les adaptations physiologiques et hormonales chez les footballeurs tunisiens

Thesis

Jul 2019

Ce travail de thèse avait pour objectifs d’évaluer les effets de certains antécédents socioprofessionnels sur le développement du syndrome de burnout chez des footballeurs professionnels de la ligue nationale tunisienne de football, de vérifier les effets de l'heure d’entraînement en force sur les variations des concentrations plasmatiques de testostérone (T) et de cortisol (C) ainsi que les rapports T/C chez des athlètes amateurs masculins tunisiens, et aussi d’évaluer les variations des niveaux de ces deux hormones aussi bien que leurs rapports, et les performances physiologiques chez des joueurs de football professionnels de la ligue précitée et ceci au cours d'une saison footballistique. Dans la première partie de l’étude, nous avons démontré que les joueurs professionnels tunisiens de football souffraient du syndrome de burnout, et que les facteurs ‘Intégration’, ‘Relation avec l’entraîneur’, ‘Age’, ‘Condition matérielle’ et l’Ancienneté’ favorisaient d’une façon significative son déclenchement. La manifestation de ce syndrome semblait être particulièrement la conséquence du développement de ses trois composantes à savoir l’épuisement émotionnel, le cynisme et la réduction de l’accomplissement personnel. Dans la seconde partie de l’étude, nos résultats ont montré que l'entraînement de force pendant huit semaines induisait une augmentation du T et du rapport T/C, et une diminution du C plasmatiques chez les athlètes amateurs qui s’entraînaient uniquement une seule fois par jour principalement l'après-midi comparativement à ceux qui se soumettaient aux mêmes exercices physiques deux fois au cours de la journée. Une réduction du T et du rapport T/C, et une augmentation du C plasmatiques ont été observées chez les athlètes qui s’entraînaient toujours successivement le matin et l'après-midi. Le rapport T/C plasmatique a toujours montré dans sa variation diurne une rythmicité circadienne chez tous les athlètes indiquant ainsi un faible niveau le matin qui devenait optimal l'après-midi. Dans la troisième partie de l’étude, on a démontré que la concentration de C augmentait à la mi-saison d'environ 23% atteignant ainsi sa valeur optimale au cours de la saison footballistique chez les joueurs professionnels tunisiens de football. Des augmentations de concentrations significatives ont été notées pour T entre la fin de la saison et la période de post-préparation d’une part, et la mi-saison d’autre part. Le rapport T/C a augmenté lors de la période de post-préparation puis a diminué au milieu de la saison compétitive. De plus, les paramètres de performance anaérobie alactique ont diminué significativement en milieu et à la fin de la saison par rapport à son début. D'un point de vue appliqué, cette étude suggère que les athlètes devraient toujours s'entraîner l'après-midi pour maximiser leurs gains de performance. De plus, la T, le C et le rapport T/C pourraient être utilisés comme indicateurs de stress et d'état de récupération d'un athlète. Les entraîneurs peuvent utiliser ces paramètres combinés avec d'autres indicateurs pour optimiser les charges de travail et éviter le surentraînement et l’épuisement.

Neo-natal castration leads to subtle differences in porcine anterior cruciate ligament morphology and function in adolescence

Preprint

Jan 2023

Female adolescent athletes are at a higher risk of tearing their anterior cruciate ligament (ACL) than male counterparts. While most work related to hormones has focused on the effects of estrogen to understand the increased risk of ACL injury, there are other understudied factors, including testosterone. The purpose of this study was to determine how surgical castration in the male porcine model influences ACL size and function across skeletal growth. Thirty-six male Yorkshire crossbreed pigs were raised to 3 (juvenile), 4.5 (early adolescent), and 6 months (adolescent) of age. Animals were either castrated (barrows) within 1-2 weeks after birth or were left intact (boars). Post-euthanasia, joint and ACL size were assessed via MRI, and biomechanics were assessed via a robotic testing system. Joint size increased throughout age, yet barrows had smaller joints than boars (p<0.001 for all measures). ACL cross-sectional area (CSA), length, volume, and stiffness all increased with age (p<0.0001), as did ACL anteromedial (AM) bundle percent contribution to resisting applied loads (p=0.012). Boar ACL and AM bundle volumes were 18% (p=0.003) and 24% (p=0.004) larger than barrows across ages. However, CSA, stiffness, and bundle contribution were similar between boars and barrows (p>0.05). The barrows had smaller temporal increases in AM bundle percent function than boars, but these data were highly variable. Thus, early and sustained loss in testosterone leads to subtle differences in ACL morphology, but may not influence measures associated with increased injury risk, such as CSA or bundle forces in response to applied loads.

Mechanisms of Muscle Cells Alterations and Regeneration Decline During Aging

Article

Nov 2024
AGEING RES REV

Cohort studies using 3D-CT are needed to assess whether “home Gym-Bed” exercises are beneficial against sarcopenia

Article

Full-text available

Sep 2024

Josef Finsterer

I was interested to read the article by Quadrelli et al. on a study on the prevention of sarcopenia using daily "Home Gym Bed" training for 30 minutes per day over 10 years in a 70-year-old man who was examined using 3D CT imaging.1 It was found that muscle mass did not change over the 10 years despite ageing.1 It was concluded that whole-body exercise in bed can help preserve muscle mass and density in older people,1 and that advanced imaging techniques can quantify the effectiveness of non-pharmacological interventions against sarcopenia.1 The study is excellent, but some points should be discussed.[...]

FGF21 mediating sex dependent response to dietary macronutrients

Article

May 2024

Sex is key variable influencing body composition and substrate utilization. At rest, females maintain greater adiposity than males and resist the mobilization of fat. Males maintain greater lean muscle mass and mobilize fat readily. Determining the mechanisms that direct these sex-dependent effects is important for both reproductive and metabolic health. Here we highlight the fundamental importance of sex in shaping metabolic physiology and assess growing evidence that the hepatokine Fibroblast growth factor-21 (FGF21) plays a mechanistic role to facilitate sex-dependent responses to a changing nutritional environment. First, we examine the importance of sex in modulating body composition and substrate utilization. We summarize new data that point towards sex-biased effects of pharmacologic FGF21 administration on these endpoints. When energy is not limited, metabolic responses to FGF21 mirror broader sex differences; FGF21-treated males conserve lean mass at the expense of increased lipid catabolism whereas FGF21-treated females conserve fat mass at the expense of reduced lean mass. Next, we examine the importance of sex in modulating the endogenous secretion of FGF21 in response to changing macronutrient and energy availability. During the resting state when energy is not limited, macronutrient imbalance increases the secretion of FGF21 more so in males than females. When energy is limited, the effect of sex on both the secretion of FGF21 and its metabolic actions may be reversed. Altogether, we argue that a growing literature supports FGF21 as a plausible mechanism contributing to the sex dependent mobilization vs preservation of lipid storage and highlight the need for further research.

Transcriptome Analysis of Left Versus Right Intrinsic Laryngeal Muscles Associated with Innervation

Article

May 2024
LARYNGOSCOPE

Objectives/Hypothesis Recurrent laryngeal nerve injury diagnosed as idiopathic or due to short‐term surgery‐related intubation exhibits a higher incidence of left‐sided paralysis. While this is often attributed to nerve length, it is hypothesized there are asymmetric differences in the expression of genes related to neuromuscular function that may impact reinnervation and contribute to this laterality phenomenon. To test this hypothesis, this study analyzes the transcriptome profiles of the intrinsic laryngeal muscles (ILMs), comparing gene expression in the left versus right, with particular attention to genetic pathways associated with neuromuscular function. Study Design Laboratory experiment. Methods RNA was extracted from the left and right sides of the rat posterior cricoarytenoid (PCA), lateral thyroarytenoid (LTA), and medial thyroarytenoid (MTA), respectively. After high‐throughput RNA‐Sequencing, 88 samples were organized into 12 datasets according to their age (P15/adult), sex (male/female), and muscle type (PCA/LTA/MTA). A comprehensive bioinformatics analysis was conducted to compare the left‐right ILMs across different conditions. Results A total of 774 differentially expressed genes were identified across the 12 experimental groups, revealing age, sex, and muscle‐specific differences between the left versus right ILMs. Enrichment analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways implicated several genes with a left‐right laryngeal muscle asymmetry. These genes are associated with neuronal and muscular physiology, immune/inflammatory response, and hormone control. Conclusion Bioinformatics analysis confirmed divergent transcriptome profiles between the left‐right ILMs. This preliminary study identifies putative gene targets that will characterize ILM laterality. Level of Evidence N/A Laryngoscope , 2024

Skeletal Muscle Injury in Chronic Kidney Disease—From Histologic Changes to Molecular Mechanisms and to Novel Therapies

Article

Full-text available

May 2024
INT J MOL SCI

Chronic kidney disease (CKD) is associated with significant reductions in lean body mass and in the mass of various tissues, including skeletal muscle, which causes fatigue and contributes to high mortality rates. In CKD, the cellular protein turnover is imbalanced, with protein degradation outweighing protein synthesis, leading to a loss of protein and cell mass, which impairs tissue function. As CKD itself, skeletal muscle wasting, or sarcopenia, can have various origins and causes, and both CKD and sarcopenia share common risk factors, such as diabetes, obesity, and age. While these pathologies together with reduced physical performance and malnutrition contribute to muscle loss, they cannot explain all features of CKD-associated sarcopenia. Metabolic acidosis, systemic inflammation, insulin resistance and the accumulation of uremic toxins have been identified as additional factors that occur in CKD and that can contribute to sarcopenia. Here, we discuss the elevation of systemic phosphate levels, also called hyperphosphatemia, and the imbalance in the endocrine regulators of phosphate metabolism as another CKD-associated pathology that can directly and indirectly harm skeletal muscle tissue. To identify causes, affected cell types, and the mechanisms of sarcopenia and thereby novel targets for therapeutic interventions, it is important to first characterize the precise pathologic changes on molecular, cellular, and histologic levels, and to do so in CKD patients as well as in animal models of CKD, which we describe here in detail. We also discuss the currently known pathomechanisms and therapeutic approaches of CKD-associated sarcopenia, as well as the effects of hyperphosphatemia and the novel drug targets it could provide to protect skeletal muscle in CKD.

Unraveling sex-specific risks of knee osteoarthritis before menopause: Do sex differences start early in life?

Article

Full-text available

May 2024
OSTEOARTHR CARTILAGE

Comparing the Impacts of Testosterone and Exercise on Lean Body Mass, Strength and Aerobic Fitness in Aging Men

Article

Full-text available

Apr 2024

Background Based on the largely untested premise that it is a restorative hormone that may reverse the detrimental impacts of aging, prescription of testosterone (T) has increased in recent decades despite no new clinical indications. It is apparent that middle-aged and older men with low-normal serum T levels are considering T supplementation as an anti-aging strategy. At the same time, there is evidence that physical activity (PA) is at historical lows in the Western world. In this review, we compare the impacts of T treatment aimed at achieving physiological T concentrations in middle-aged and older men, alongside the impacts of ecologically relevant forms of exercise training. The independent, and possible combined, effects of T and exercise therapy on physiological outcomes such as aerobic fitness, body composition and muscular strength are addressed. Main Body Our findings suggest that both T treatment and exercise improve lean body mass in healthy older men. If improvement in lean body mass is the primary aim, then T treatment could be considered, and the combination of T and exercise may be more beneficial than either in isolation. In terms of muscle strength in older age, an exercise program is likely to be more beneficial than T treatment (where the dose is aimed at achieving physiological concentrations), and the addition of such T treatment does not provide further benefit beyond that of exercise alone. For aerobic fitness, T at doses aimed at achieving physiological concentrations has relatively modest impacts, particularly in comparison to exercise training, and there is limited evidence as to additive effects. Whilst higher doses of T, particularly by intramuscular injection, may have larger impacts on lean body mass and strength, this must be balanced against potential risks. Conclusion Knowing the impacts of T treatment and exercise on variables such as body composition, strength and aerobic fitness extends our understanding of the relative benefits of physiological and pharmacological interventions in aging men. Our review suggests that T has impacts on strength, body composition and aerobic fitness outcomes that are dependent upon dose, route of administration, and formulation. T treatment aimed at achieving physiological T concentrations in middle-aged and older men can improve lean body mass, whilst exercise training enhances lean body mass, aerobic fitness and strength. Men who are physically able to exercise safely should be encouraged to do so, not only in terms of building lean body mass, strength and aerobic fitness, but for the myriad health benefits that exercise training confers.

Size matters: the biochemical logic of ligand type in endocrine crosstalk

Article

Full-text available

Dec 2023

The endocrine system is a fundamental type of long-range cell-cell communication that is important for maintaining metabolism, physiology, and other aspects of organismal homeostasis. Endocrine signaling is mediated by diverse blood-borne ligands, also called hormones, including metabolites, lipids, steroids, peptides, and proteins. The size and structure of these hormones are fine-tuned to make them bioactive, responsive, and adaptable to meet the demands of changing environments. Why has nature selected such diverse ligand types to mediate communication in the endocrine system? What is the chemical, signaling, or physiologic logic of these ligands? What fundamental principles from our knowledge of endocrine communication can be applied as we continue as a field to uncover additional new circulating molecules that are claimed to mediate long-range cell and tissue crosstalk? This review provides a framework based on the biochemical logic behind this crosstalk with respect to their chemistry, temporal regulation in physiology, specificity, signaling actions, and evolutionary development.

The contribution of mitochondria to age-related skeletal muscle wasting: A sex-specific perspective

Article

Nov 2023
LIFE SCI

Eight weeks of heavy strength training increases hemoglobin mass and V̇O2peak in well-trained to elite female and male rowers

Article

Nov 2023
J APPL PHYSIOL

Purpose O 2 -transport and endurance exercise performance are greatly influenced by hemoglobin mass (Hb mass ), which largely depends on lean body mass (LBM). This study investigated the effects of 8 weeks with 3 weekly sessions of conventional (3-SET: 3x10 reps) or high-volume strength training (10-SET: 5-10x10 reps) on LBM, Hb mass , muscle strength, and exercise performance in female and male rowers. Methods Hematological parameters were obtained through CO re-breathing and body composition by DEXA scans before and after the training period. Concomitantly, V̇O 2 peak was determined during 2-km ergometer rowing and muscle strength by isometric mid-thigh pull. Results There were no differences in training responses between groups for any of the parameters. Pooled data, revealed overall increments for Hb mass (10-SET: 882±199g to 897±213g; 3-SET: 936±245g to 962±247g, P=0.02) and V̇O 2 peak (10-SET: 4.3±1.0 to 4.4±0.9 L∙min ⁻¹ ; 3-SET: 4.5±0.9 to 4.6±0.9 L∙min ⁻¹ , P=0.03), while LBM remained unchanged (10-SET: 58.7±10.5 to 58.7±10.1kg; 3-SET: 64.1±10.8 to 64.5±10.6kg, P=0.42). Maximal isometric mid-thigh pull strength increased (10-SET: 224±47kg to 237±55kg; 3-SET: 256±77kg to 281±83kg, P=0.001). Strong associations were observed between LBM and Hb mass and V̇O 2 peak (r ² =0.88-0.90), entailing sex differences in Hb mass and V̇O 2 peak. Normalizing V̇O 2 peak to LBM reduced the sex difference to ~10%, aligning with the sex difference in Hb mass ∙LBM ⁻¹ . Conclusion Strength training successfully increased Hb mass and V̇O 2 peak in elite female and male rowers, without an additional effect from increased training volume. Moreover, sex differences in V̇O 2 peak were mainly explained by differences in LBM, but likely also by differences in Hb mass ∙LBM ⁻¹ .

Neo-Natal Castration Leads to Subtle Differences in Porcine Anterior Cruciate Ligament Morphology and Function in Adolescence

Article

Oct 2023

Female adolescent athletes are at a higher risk of tearing their anterior cruciate ligament (ACL) than male counterparts. While most work related to hormones has focused on the effects of estrogen to understand the increased risk of ACL injury, there are other understudied factors, including testosterone. The purpose of this study was to determine how surgical castration in the male porcine model influences ACL size and function across skeletal growth. Thirty-six male Yorkshire crossbreed pigs were raised to 3 (juvenile), 4.5 (early adolescent), and 6 months (adolescent) of age. Animals were either castrated (barrows) within 2 weeks after birth or were left intact (boars). Post-euthanasia, joint and ACL size were assessed via MRI, and biomechanics were assessed via a robotic testing system. Joint size increased throughout age, yet barrows had smaller joints than boars. ACL cross-sectional area (CSA), length, volume, and in situ stiffness increased with age, as did ACL anteromedial (AM) bundle percent contribution to resisting loads. Boar ACL, AM bundle, and PL bundle volumes were 19%, 25%, and 15% larger than barrows across ages. However, CSA, in situ stiffness, and bundle contribution were similar between boars and barrows. The barrows had smaller temporal increases in AM bundle percent function than boars, but these data were highly variable. Thus, early and sustained loss in testosterone leads to subtle differences in ACL morphology but may not influence measures associated with increased injury risk, such as CSA or bundle forces in response to applied loads.

Effect of Age and Sex on Percentage of Retail Cuts and Offal Yield of Local Goats in Pakistan

Article

Oct 2023

Goat meat is an important source of protein in the human diet, and its popularity has led to increased interest in studying the retail cuts and offal yield of goat carcasses. This study aimed to investigate the effect of age and sex on the percentage of retail cuts and offal yield of local goats in Pakistan. Thirty-six goats were randomly selected and divided into four groups based on sex and age. Groups A and B consisted of male goats with milk teeth and two teeth respectively, while groups C and D consisted of female goats with milk teeth and two teeth respectively. There were nine goats in each cohort. The results showed that age had a significant effect on the percentage of retail cuts, with two-teeth animals (male or female) having higher values than milk teeth animals. When comparing different age groups, the retail cuts in two teeth male goats showed higher percentages for forelimb (19.78% vs 17.09%), neck (9.96% vs 8.48%), ribs (7.31% vs 6.02%), breast (7.06% vs 5.57%), shoulder (15.46% vs 12.97%), chops (12.73% vs 10.61%), hind limb (37.34% vs 30.48%), flank (5.18% vs 3.71%), and sirloin (10.70% vs 8.26%) compared to milk teeth male goats. Comparison of two teeth female goats to milk teeth female goats, the average percentage of retail cuts in two teeth females was higher for forelimb (18.90% vs 16.60%), neck (9.40% vs 8.15%), ribs (6.60% vs 5.54%), breast (6.48% vs 5.17%), shoulder (14.70% vs 12.59%), chops (12.04% vs 10.02%), hind limb (35.32% vs 28.79%), flank (4.96% vs 3.43%), and sirloin (9.92% vs 7.51%) However, sex did not have a significant effect on retail cuts. Offal yield was influenced by both age and sex, with male goats and milk teeth animals showing higher values. Comparison between two-teeth and milk teeth animals showed significant differences in offal yield. Comparison of killing out percentage between different age and sex group shows average killing out percentage in two teeth male was 51.325, in two teeth female 51.402, in milk teeth male 48.601 and in milk teeth female 48.083. The study concluded that the effect of age on dressing percentage was significant, but the effect of sex was not significant. The killing out percentage value was higher in two-teeth animals and lower in milk teeth animals, but there was no significant difference between male and female goats. Overall, the study provides important insights into the optimal age and sex for slaughtering goats to achieve maximum returns and standardize the retail cuts of local Pakistani goats.

Expected vs. perceived effects of gender-affirming hormone therapy among transmasculine adolescents

Article

Sep 2023

Objectives Gender-affirming testosterone therapy is increasingly prescribed among transmasculine adolescents and has been associated with improved mental health outcomes. However, expected and perceived effects of testosterone have not previously been compared in this population. Methods We compared desired and reported effects of testosterone in all consecutive transmasculine adolescents followed at a large interdisciplinary gender diversity clinic in North America. Participants received a prescription for testosterone and were first seen between November 2016 and May 2021. Our study was a retrospective audit of case notes. We collected self-reported desired effects prior to initiation of testosterone and self-reported perceived effects from participants’ medical records up to 24 months after initiation. The masculinizing effects of testosterone considered in our study were increased body/facial hair, voice deepening/Adam’s apple growth, increased muscle mass, clitoromegaly, and body fat redistribution. Results There were 76 participants included in this study. Mean age at prescription of testosterone was 16.31 years (standard deviation: 0.99 years). The effects desired by the greatest proportion of participants prior to initiation were increased body/facial hair (69 %) and voice deepening/Adam’s apple growth (52 %). These same two effects were the most reported by participants, reaching 80 % report rates at 12 months, and increasing steadily across the 24-month follow-up period. Conclusions Our study shows that for most, but not all gender diverse adolescents undergoing testosterone therapy, the most expected physical changes were seen in the first year of gender-affirming treatment. More research and provider education are needed to offer optimal counseling for adolescents undergoing gender-affirming hormone therapy.

A sex-specific association of leukocyte telomere length with thigh muscle mass

Article

Sep 2023

Objectives Telomeres are DNA–protein complexes at the ends of linear chromosomes that protect against DNA degradation. Telomeres shorten during normal cell divisions and therefore, telomere length is an indicator of mitotic-cell age. In humans, telomere shortening is a potential biomarker for disease risk, progression and premature death. Physical activity has been associated with longer leukocyte telomere length (LTL) in some studies. In the current study the relationship between LTL, thigh muscle mass and adipose tissue distribution was explored. Methods We performed anthropometric measurements and magnetic resonance imaging (MRI) measurements of the thigh in 149 healthy subjects (77 male, 72 female). LTL was measured using qPCR. Additionally, the subjects answered a questionnaire concerning their training behaviour. Results In male subjects, LTL was significantly associated with thigh muscle mass, independent of age and body mass index (p=0.006). In addition, a slight association of LTL with weekly endurance units in the male group was found. These relations could not be observed in females. Conclusions In conclusion, we observed a sex-specific association of LTL and thigh muscle mass in healthy males. The reason of this sex-specific association is currently unclear, but could be related to different training effects and/or hormonal pathways in men and women.

Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions

Article

Full-text available

Jun 2023
PHYSIOL REV

Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill-trained. Much of the pre-clinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and post-exercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest additional mechanisms that feed into or are independent of these processes are also involved. This review will first provide a historical account as to how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms will be proposed.

Understanding Heterogeneity in the Relationship Between Cancer and Hand Grip Strength: A Longitudinal Analysis

Article

Apr 2023
RES AGING

This study examined whether the relationship between cancer and hand grip strength differs by sex and along the hand grip strength distribution. Using six waves of the Korean Longitudinal Study of Ageing (KLoSA) (N = 9735), sex-stratified unconditional quantile regression models with fixed effects were used to assess sex-specific effects of cancer for patients in different quantiles of the hand grip strength distribution. Cancer diagnosis was negatively associated with hand grip strength for males, but not females, and this sex difference was statistically significant. Quantile regression models showed that the stronger association between cancer and hand grip strength is observed among males with weaker hand grip strength. No statistically significant association was found between hand grip strength and cancer in females across the entire distribution of hand grip strength. This study provided evidence of the heterogeneity in the relationship between cancer and hand grip strength.

Male sex hormones, aging, and inflammation

Article

Full-text available

Jan 2023
BIOGERONTOLOGY

Adequate levels of androgens (eugonadism), and specifically testosterone, are vital compounds for male quality of life, longevity, and positive health outcomes. Testosterone exerts its effects by binding to the androgen receptor, which is expressed in numerous tissues throughout the body. Significant research has been conducted on the impact of this steroid hormone on skeletal, muscle and adipose tissues and on the cardiovascular, immune, and nervous systems. Testosterone levels have also been studied in relation to the impact of diseases, aging, nutrition and the environment on its circulating levels. Conversely, the impact of testosterone on health has also been evaluated with respect to its cardiac and vascular protective effects, body composition, autoimmunity and all-cause mortality. The male aging process results in decreasing testosterone levels over time. The exact mechanisms and impact of these changes in testosterone levels with age on health- and life-span are still not completely clear. Further research is needed to determine the optimal testosterone and androgen levels to protect from chronic age-related conditions such as frailty and osteoporosis.

Nutritional Implications of Sex and Age Differences in Energy Metabolism

Chapter

Dec 2009

Effect of testosterone on muscle and muscle protein synthesis

Abstract

No full-text available

Recommended publications

Leucine incorporation into mixed skeletal muscle in humans