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Skeletal Muscle Hypertrophy After Aerobic Exercise Training
Abstract
Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss.
Although not commonly associated with gains in skeletal muscle mass, aerobic exercise stimulates muscle protein synthesis and skeletal muscle hypertrophy.
... 5 When performed correctly, aerobic exercise can lead to skeletal muscle hypertrophy comparable to that achieved through resistance exercise training. 15,16 While numerous reviews have emphasized the advantageous effects of exercise on alterations in skeletal muscle mass, there is a limited discussion regarding the impact of aerobic exercise intensity on the regulation of skeletal muscle mass. This review aims to elucidate the significance of precise training parameters, including exercise intensity in the regulation of skeletal muscle mass. ...
... Moreover, acute aerobic exercise has shown the ability to restore the sensitivity to the anabolic effects of insulin in older adults, leading to the stimulation of intracellular anabolic signaling pathways and the promotion of a positive protein balance that is not evident in sedentary individuals. 16 . ...
Endurance training, a form of physical activity that relies on continuous aerobic exercise and repetitive muscle contractions, is widely acknowledged for its positive effects on overall physical fitness. Aerobic exercise, an essential component of endurance training, has numerous benefits including improved cardiovascular and respiratory health, increased muscle endurance, and enhanced resistance against fatigue. It has also been found to contribute to skeletal muscles, potentially by stimulating the synthesis of proteins involved in muscle fiber formation. Although resistance exercise has been favored for promoting muscle growth, some suggests that aerobic exercise can also produce skeletal muscle hypertrophy comparable to that of resistance exercise if performed correctly. The duration, intensity, and specific type of aerobic exercise play important roles in determining skeletal muscle mass. The mammalian target of rapamycin (mTOR) known as a key regulator of muscle protein synthesis that associated with exercise activity. Several signaling pathways, such as Akt/mTOR and MAPK, are involved in controlling muscle protein synthesis during exercise. This review aimed to understand the impact of aerobic exercise intensity and other training parameters on skeletal muscle, to provide valuable insights for optimizing exercise programs and fostering muscle hypertrophy. In this review, we had systematically searched PubMed and Google Scholar from January 2013 to May 2023. Our result indicated that aerobic exercise can be expected to promote skeletal muscle hypertrophy and improve muscle mass and function. The regulation of skeletal muscle mass is complex, involving various signaling pathways such as mTOR, as well as the influence of hormones and growth factors.
... Endurance exercise is known for stimulating PGC-1α, which is believed to be the master regulator of mitochondrial biogenesis, muscle oxidative capacity, and protein metabolism (Millay & Olson, 2013). Improvements in mitochondrial metabolism may contribute to skeletal muscle contractility and anabolism after aerobic exercise training (Konopka & Harber, 2014). In this study, exercise training improved PGC-1α, mTOR, and p-p70S6K muscle protein expression compared to the HF group. ...
... muscle mass loss in the trained HF group. Furthermore, exercise training not only enhances muscle biosynthesis but also reduces markers of muscle degradation, such as Atrogin-1 and MuRF-1, and protects against early mitochondria-mediated apoptotic signaling caused by obesity (BAX/Bcl-2 ratio and caspase-3 expression) (Harber et al., 2012;Konopka & Harber, 2014). Our research findings support these claims, as we observed the downregulation of UPP pathways and apoptotic markers in trained groups, mitigating obesity-induced myofiber atrophy. ...
Obesity over‐activates the classical arm of the renin‐angiotensin system (RAS), impairing skeletal muscle remodeling. We aimed to compare the effect of exercise training and enalapril, an angiotensin‐converting enzyme inhibitor, on RAS modulation in the skeletal muscle of obese animals. Thus, we divided C57BL/6 mice into two groups: standard chow (SC) and high‐fat (HF) diet for 16 weeks. At the eighth week, the HF‐fed animals were divided into four subgroups—sedentary (HF), treated with enalapril (HF‐E), exercise training protocol (HF‐T), and combined interventions (HF‐ET). After 8 weeks of treatment, we evaluated body mass and index (BMI), body composition, exercise capacity, muscle morphology, and skeletal muscle molecular markers. All interventions resulted in lower BMI and attenuation of overactivation in the classical arm, while favoring the B2R in the bradykinin receptors profile. This was associated with reduced apoptosis markers in obese skeletal muscles. The HF‐T group showed an increase in muscle mass and expression of biosynthesis markers and a reduction in expression of degradation markers and muscle fiber atrophy due to obesity. These findings suggest that the combination intervention did not have a synergistic effect against obesity‐induced muscle remodeling. Additionally, the use of enalapril impaired muscle's physiological adaptations to exercise training.
... We also found that sufficient aerobic exercise had an independent lower odds of dynapenia, even after adjusting for the level of resistance exercise and other confounders. Previous studies have reported that aerobic exercise alone can improve muscle function and mass [32,33]. ...
... First, aerobic exercise may not have been sufficient to improve the muscle strength of these participants. The proposed mechanisms for the effectiveness of aerobic exercise on muscle strength or mass are the reduction of reactive oxygen species by mitochondrial energetics and improvement of muscle protein metabolism [33]. Previous studies have reported that patients with CVD or CLD exhibit mitochondrial dysfunction and impaired protein metabolism [39][40][41]. ...
Background
Physical activity (PA) behaviours and comorbid diseases are associated with muscle strength. However, the association between dynapenia and detailed PA behaviours, including participation in aerobic and resistance exercises and sedentary behaviour (SB), in relation to comorbid diseases has not yet been investigated. Using nationwide data, this study aimed to evaluate the independent association of dynapenia with detailed PA behaviour (participation in aerobic and resistance exercises and SB), and assess the differential associations of detailed PA behaviour with dynapenia according to comorbid diseases with prevalent sarcopenia.
Methods
A total of 7,558 community-dwelling older adults aged ≥ 65 years who were included in the Korea National Health and Nutrition Examination Survey from 2014 to 2019 were included in the present study. Cross-sectional associations between PA behaviours (participation in aerobic exercise, participation in resistance exercise, and SB) and dynapenia were analysed using complex-sample multivariable-adjusted logistic regression models according to the type of comorbid disease (cardiovascular disease [CVD], diabetes mellitus [DM], and chronic lung disease [CLD]).
Results
Sufficient aerobic exercise, sufficient resistance exercise, and low sedentary time of < 420 min/day showed independent negative associations with dynapenia (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.60–0.83; OR, 0.54; 95% CI, 0.42–0.69; and OR, 0.84; 95% CI, 0.72–0.97, respectively). Among the participants with CVD or CLD, the associations of sufficient resistance exercise (OR, 0.46; 95% CI, 0.26–0.82 and OR, 0.51; 95% CI, 0.35–0.75 for CVD and CLD, respectively) and low sedentary time (OR, 0.66; 95% CI, 0.45–0.98 and OR, 0.71; 95% CI, 0.55–0.93 for CVD and CLD, respectively) with dynapenia were significant, whereas the association of sufficient aerobic exercise with dynapenia was insignificant. Meanwhile, in participants with DM, sufficient aerobic exercise (OR, 0.70; 95% CI, 0.52–0.94) and sufficient resistance exercise (OR, 0.45; 95% CI, 0.29–0.70) were independently associated with dynapenia, whereas no association between SB and dynapenia was found.
Conclusion
We observed an independent inverse association between PA behaviours and dynapenia. Disease-specific associations between each PA behaviour (sufficient aerobic exercise, sufficient resistance exercise, and low sedentary time) and dynapenia differed in the older adults. Therefore, these differences should be acknowledged during interventions for this population.
... Although aerobic exercise, such as walking, has been shown to increase muscle size in older adults and sedentary people (18), the stimuli at the muscle level is usually suboptimal for inducing muscle hypertrophy compared with resistance training (13). The 3 mechanisms of muscle hypertrophy include mechanical tension, muscle damage, and metabolic stress (36). ...
... It appears that improvements in muscle strength following BFR walking interventions are lower than the ;30% improvement in strength following traditional high-intensity (;75-85% 1RM) resistance training in older adults (18). Despite a lower strength gain than traditional resistance training, BFR walking could be an alternative to traditional resistance training for frail older adults who cannot tolerate high mechanical and physiological stress. ...
Walking is a low-impact form of physical activity feasible, acceptable, and safe for load-compromised individuals, such as older adults. Options available to increase the potency of this exercise to promote training adaptations are generally limited to manipulation of speed, gradient, and duration. However, emerging studies have suggested that blood flow restriction (BFR) combined with walking is a method that can accentuate training-induced adaptations compared with walking alone. This narrative review aimed to examine the effectiveness and safety of BFR walking in older adults according to the existing literature. Of the limited evidence available on this topic, it appears that BFR walking compared with walking alone can induce significant increases in muscular hypertrophy and strength. Therefore, implementing BFR walking may be a feasible and safe option for older adults to enhance the effectiveness of their walking interventions, at least from a musculoskeletal perspective.
... 32 Regular aerobic exercise with the inclusion of a total body exercise has the effect of increasing muscle mass by causing muscle hypertrophy, which has been observed to occur in a short period of two weeks after initiation of training. 33,34 This causes an increase in muscle mass and would explain why some recruits had stable weight or weight gain. Furthermore, prolonged exercise leads to a decrease in body fat from the increase in lipolysis and fat oxidation. ...
Introduction: Cardiorespiratory fitness is crucial for safe and efficient performance in executing firefighting tasks. The study aims to assess the effects of Phase 1 of a newly designed 4-week physical training regimen on changes in cardiorespiratory fitness, health parameters and other physical fitness elements. Phase 1 was crafted to primarily focus on improving firefighter recruits' cardiorespiratory fitness to prime their body for the subsequent phase of exercise. Materials and Methods: A quasi-experimental study employing a one-group pre-and post-intervention was carried out involving 142 male firefighter recruits from a Fire and Rescue Academy in Malaysia. Various aspects of physical fitness changes, including speed, agility, and coordination (SAC), muscle strength, endurance, and power, were evaluated at baseline (Week 1) and upon completion of the first phase (Week 5). Changes in health parameters, such as blood pressure, resting heart rate, body weight, muscle mass, body fat percentage, and body mass index, were also assessed. A paired sample t-test was conducted with the significance level set at 0.05. The magnitude of changes was assessed using the following criteria: values of 0.3 were considered a small effect size, 0.5 indicated a moderate effect size, and 0.8 signified a large effect size. Results: Upon completion of the first phase of the physical training regimen, there was a statistically significant improvement in cardiorespiratory fitness, with a mean increment of VO2max was 9 mL/kg/min (95% CI: 8.33, 9.58, p<0.001, large effect size of 2.40). Both pre-and post-intervention assessments of abdominal and upper body muscle strength and endurance showed statistically significant improvement with the mean difference of 11 sit-ups (95%CI: 10.08, 12.01; p<0.001, large effect size of 1.89) and 1.5 pull-ups (95%CI: 1.07, 1.86; p<0.001, moderate effect size of 0.63), respectively. Health parameters showed similar, except for systolic BP (SBP). There was a small increment in recruits' SBP following the 4-week training period with a mean difference of 4.3 mmHg (95%CI: 2.37, 6.24; effect size = 0.37, p<0.001). Conclusion: The first phase of the newly introduced four-week physical training regimen has proven effective in enhancing cardiorespiratory fitness, as well as abdominal and upper body muscle strength and endurance. Additionally, the regimen has positively influenced several health parameters, except for systolic blood pressure. The observed increase in average systolic blood pressure indicates a necessity for continuous monitoring at the academy to address this issue effectively.
... It is likely this focus that led to the improvements seen in cardiorespiratory fitness in this study within the intervention group and it is plausible that this may have also contributed to greater increases in muscle mass. 38 An increase in muscle mass concurrent with a fat mass decrease may result in minimal change in overall body weight, while producing other significant health improvements. Support for this comes from a recent study that has proposed a weightneutral strategy for obesity treatment, arguing that increasing PA and cardiorespiratory fitness has a myriad of health benefits including positive impacts on cardiometabolic risk markers as well as decreased risk for mortality, even in the absence of weight loss. ...
Background
Obesity disproportionately impacts men’s health yet fewer men engage in preventive healthcare. We examined the effectiveness of Hockey Fans in Training (Hockey FIT), a gender-sensitised lifestyle intervention that engages men with overweight/obesity through their passion as fans of a local sports team, on weight change and other health indicators.
Methods
Pragmatic, cluster randomised trial (aged 35–65 years, body mass index ≥ 27 kg/m²) within 42 community-based sites in Canada and the United States, randomly assigned (1:1) to intervention (Hockey FIT) or control (wait-list) and stratified by region. Sites were selected based on partnerships with local major junior/professional hockey teams and community implementation partners. Intervention participants received exercise and education during a three-month active phase (once-weekly, 90-min sessions) followed by a nine-month minimally-supported phase; control participants continued with usual activities. Primary outcome was weight change at 12 months. Assessment teams were blinded to group assignment including photos of weight measurements on digital scales, to provide proof of values recorded (post COVID-19). Analyses followed intent-to-treat. Trial registration: ClinicalTrials.gov, NCT03636282.
Findings
Between November 13, 2018–November 12, 2021, 20 sites (n = 497) were allocated to intervention and 22 sites (n = 500) to control. Participants with baseline weight and weight at 3 or 12 months, were included in the primary analysis (20 intervention sites [n = 354]; 22 control sites [n = 425]). At 12 months, mean weight change was −2.02 kg (95% confidence interval [CI], −2.78 to −1.26) with intervention and −0.92 kg (CI, −1.58 to −0.26) with control (difference, −1.10 kg [CI, −2.11 to −0.09], p = 0.03). There were 22 non-study related serious adverse events (45.5% in intervention; 54.5% in control).
Interpretation
Hockey FIT reduced weight in men with overweight or obesity. Hockey FIT is an innovative approach to engage men at increased risk of non-communicable disease in effective health behaviour change, through their passion as fans of their local hockey team.
Funding
10.13039/100011094Public Health Agency of Canada; 10.13039/501100000024Canadian Institutes of Health Research.
... Although previous studies have not focused on the association between participation in resistance and aerobic exercise, our results suggest that engagement in both types of exercise may be closely interconnected and clustered as part of positive health behaviors. Furthermore, aerobic exercise not only positively influences the reduction in comorbidities but also affects skeletal muscle and bone density [32,33]. Therefore, the benefits of aerobic exercise on body function may enhance RE participation, which can be challenging for older adults with comorbidities. ...
Background/Objectives: Despite the importance of resistance exercise in older adults, factors associated with participation remain unclear, especially regarding sex differences. This study investigated sociodemographic, behavioral, and comorbidity factors associated with insufficient resistance exercise participation among community-dwelling older adults in Korea, with analyses stratified by sex. Methods: Nationally representative cross-sectional data from 8671 participants aged ≥65 years (3758 men and 4913 women; mean age 72.8) were analyzed using the 6th-8th Korea National Health and Nutrition Examination Surveys (2014–2019). Complex-sample multivariable logistic regression identified factors associated with insufficient resistance exercise overall and by sex. Results: Women had a higher prevalence of insufficient resistance exercise than men (91.27% vs. 71.04%, p < 0.001). Older age groups, particularly those aged ≥80 years (OR: 2.39; 95% CI: 1.86–3.07), and those with lower education (OR: 1.56; 95% CI: 1.33–1.82), rural residence (OR: 1.89; 95% CI: 1.49–2.38), low household income, (OR: 1.45; 95% CI: 1.13–1.88), insufficient aerobic exercise (OR: 1.68; 95% CI: 1.46–1.94), current smoking (OR: 1.70; 95% CI: 1.26–2.29), and diabetes (OR: 1.28; 95% CI: 1.09–1.51) were independently associated with a higher likelihood of insufficient resistance exercise. The association of household income, current smoking, hypertension, and diabetes with resistance exercise adherence showed differences in sex-stratified analyses. Conclusions: Multiple sociodemographic, behavioral, and comorbid factors are linked to resistance exercise adherence among older Koreans. Tailored, sex-specific interventions are needed to promote resistance exercise in this population, informing public health strategies and further research on effective approaches for diverse older adults.
... This narrows the therapeutic process of the person undergoing this type of surgery and the importance of exercise as a non-medical non-pharmacological therapy [11][12][13][14][15]. For this reason, some authors propose the need for the implementation of preventive programs that combine aerobic and strength exercises, which seems to be the most effective approach for overcoming the problem of sarcopeniia [16][17][18][19][20]. ...
Purpose
Bariatric surgery is a treatment for severe obesity and its associated conditions, which already has ample evidence of its benefits. In addition to the reduction in body fat mass, the weight loss caused by bariatric surgery includes a significant reduction in skeletal muscle and bone mineral mass, which could negatively affect functional capacity and increase the risk of sarcopenia. The need for prophylactic programs that prevent sarcopenia in bariatric surgery patients seems to be one of the crucial points for the long-term surgical success of bariatric and metabolic surgery. This study aims to review the published literature regarding the effects of physical exercise on the prevention of sarcopenia induced by bariatric surgery.
Methods
We followed the PRISMA checklist for systematic reviews conducted in PubMed/Medline, EBSCO, Web of Science, and Scopus databases. Randomized controlled, controlled clinical, and other types of experimental studies were considered for inclusion. A total of 356 possibly relevant studies were identified with quality considered reasonable and good. Eight studies were included in the review: six of which were randomized experimental studies, one was a pilot study, and one a quasi-experimental study.
Results
Structured physical exercise allows significant improvements in body composition, positively affecting functional capacity, muscle strength, cardio-metabolic risk factors, and quality of life in patients with obesity undergoing bariatric surgery, especially when combined exercise is implemented in the initial weeks following surgery.
Conclusion
A combined, individualized, and supervised exercise program contributes to preventing and reducing sarcopenia after bariatric surgery.
... FES cycle training improves symptoms of spasticity but approximately 48 hours after training (31,32). However, cycling is basically considered to be aerobic, stimulate modest increases in muscular strength (33). Actually, to strengthen skeletal muscle in healthy people with aerobic training, the efficient intensity should be as a minimum of 70% heart rate reserve, four-times a week for thirty minutes. ...
... It can reduce the expression of catabolic proteins and increase protein synthesis, promoting muscle growth (Park, 2019). Aerobic exercise training also activates mitochondrial biogenesis, improves mitochondrial function and metabolic capacity, reduces oxidative stress and catabolic pathways, decreases muscle protein breakdown, and provides sufficient energy for protein synthesis (Konopka and Harber, 2014). Combining aerobic exercise and resistance exercise can enhance muscle function and cardiopulmonary function, making it an ideal intervention for sarcopenia. ...
Recent studies have revealed that sarcopenia can adversely affect the efficacy of PD-1 inhibitors in the treatment of non-small cell lung cancer (NSCLC). PD-1 inhibitors are immune checkpoint inhibitors widely used in the treatment of various cancers. However, NSCLC patients may have poorer outcomes when receiving PD-1 inhibitor treatment, and sarcopenia may affect the efficacy of PD-1 inhibitors through immune and metabolic mechanisms. In this article, we summarize the reported negative impact of sarcopenia on the effectiveness of PD-1 inhibitors in the treatment of NSCLC in recent years. Based on existing research results, we analyze the possible mechanisms by which sarcopenia affects the efficacy of PD-1 inhibitors and discuss possible strategies to address this issue. This could help to understand the impact of sarcopenia on the treatment of PD-1 inhibitors and provide more accurate expectations of treatment outcomes for clinicians and patients. Additionally, we present tailored intervention strategies for sarcopenic patients undergoing PD-1 inhibitor therapy, aiming to optimize treatment efficacy and enhance patient quality of life. Nevertheless, further research is warranted to elucidate the mechanisms through which sarcopenia impacts PD-1 inhibitors and to identify more efficacious intervention approaches for improving the effectiveness of PD-1 inhibitor treatment in sarcopenic patients.
... It was anticipated that cross-country skiers with a minimum of five years of experience in the sport would demonstrate increased REE. Aerobic exercise also increases REE, but this effect may depend on its mode and intensity, as well as on an athlete's fitness level [26]. Since more than 80% of training time on a TD is associated with aerobic exercise, we can assume that higher REE values are caused to a greater extent by adaptation to exercise. ...
Background and Objectives: A sustained mismatch between energy intake (EI) and exercise energy expenditure (EEE) can lead to Low Energy Availability (LEA), as well as health and performance impairments characteristic of Relative Energy Deficiency in Sport (RED-S). Research in females has identified specific LEA cut-points for the risks of developing physiological and performance disturbances. Cut-points in males have yet to be evaluated; therefore, this study examined the prevalence of LEA in highly trained male cross-country skiers. The key purpose of this study was to analyze EI, resting energy expenditure (REE), EEE, and energy availability (EA) in highly trained cross-country skiers during the preparation and competition periods. The secondary objective of our study was to evaluate the relative contribution of fats and carbohydrates to EI, REE, and EEE. Materials and Methods: EI was determined by an estimated 24 h diet recall method, REE was assessed by indirect calorimetry, and EEE was estimated from heart rate in 27 cross-country skiers. Results: EI amounted to 4050 ± 797 kcal/day on a typical training day (TD) and 5986 ± 924 kcal/day (p < 0.001) on a typical competition day (CD). REE on TDs (2111 ± 294 kcal/day or 30 ± 6 kcal/day/kg) was higher (p < 0.05) than on CDs (1891 ± 504 kcal/day or 27 ± 7 kcal/day/kg). The EA in the athletes was <15 kcal∙kg FFM–1·d–1 on TDs and <65 kcal∙kg FFM–1·d–1 on CDs. EI was not optimal, as indicated by low EA throughout TDs (June). This could be associated with insufficient EI along with a high amount of EEE (3690.7 ± 485.2 kcal/day). During the transition from TD to CD, an increase in the contribution of fats to EI and EEE was observed in cross-country skiers. Conclusion: The conception of LEA and REDs and their potential implication for performance is underestimated among coaches and athletes. The importance of appropriate dietary strategies is essential to ensure that enough calories are consumed to support efficient training.
... Physical exercise improves heart and respiratory functions, modulates the mTOR pathway, and transiently activates autophagy, which increases protein balance and muscle hypertrophy [9,10]. This modulation is particularly beneficial in managing DM2 and HF [11,12]. ...
Introduction : Heart failure (HF) and type 2 diabetes mellitus (DM2) are global health problems that often lead to muscle atrophy. These conditions are associated with increased autophagy and apoptosis in the muscle cells, resulting in decreased muscle mass. Materials and methods: Male rats were assigned to one of four groups: control (CT), HF+DM (disease model), exercise+HF+DM (EX+HF+DM), and EX+HF+DM+photobiomodulation (EX+HF+DM+PBM). To induce DM2, we administered streptozotocin (0.25 ml/kg, i.p.). HF was induced by coronary ligation. One week post-induction, an eight-week aerobic exercise and PBM protocol was initiated. Western blot analysis was used to measure the expression of apoptosis-related proteins and autophagy. Results: The EX+HF+DM+PBM group showed a substantial increase in Nrf2, p-AKT, and LC3-I levels compared to the HF+DM group. Conclusion: These findings suggest that physical exercise combined with PBM can upregulate proteins that promote myocyte survival in rats with HF and DM2.
... Endurance training (ET) generally refers to aerobic training like walking, running, cycling, swimming, and bodyweight exercises including squats, push-ups, lunges, etc., which increase endurance. It has been proposed that AA supplementation coupled with ET increases lean body mass and muscle strength, improves fatigue and post-exercise recovery [128], and also modulates mitochondrial protein synthesis rate in both young and older adults [129,130]. Interestingly, ET has been linked to amino acid oxidation, specifically the oxidation of BCAAs. It is speculated that the intake of BCCA during low-or highintensity endurance training can increase muscle protein synthesis and, thus, strengthen performance [128]. ...
Simple Summary
Cancer cachexia (CC) is a syndrome affecting advanced cancer patients, causing inflammation, metabolic dysfunction, and a decline in quality of life. It increases the risk of mortality. Nutritional therapies are being tested for improving muscle metabolism in cancer patients, but no special therapies have been validated in clinical practice. Studies suggest increasing muscle protein synthesis through amino acids or protein intake, and physical activity can reduce muscle atrophy. This manuscript provides an overview of the preclinical and clinical approaches for the use of amino acids with and without exercise therapy to improve muscle metabolism in cachexia.
Abstract
Cancer cachexia is a multifaceted syndrome that impacts individuals with advanced cancer. It causes numerous pathological changes in cancer patients, such as inflammation and metabolic dysfunction, which further diminish their quality of life. Unfortunately, cancer cachexia also increases the risk of mortality in affected individuals, making it an important area of focus for cancer research and treatment. Several potential nutritional therapies are being tested in preclinical and clinical models for their efficacy in improving muscle metabolism in cancer patients. Despite promising results, no special nutritional therapies have yet been validated in clinical practice. Multiple studies provide evidence of the benefits of increasing muscle protein synthesis through an increased intake of amino acids or protein. There is also increasing evidence that exercise can reduce muscle atrophy by modulating protein synthesis. Therefore, the combination of protein intake and exercise may be more effective in improving cancer cachexia. This review provides an overview of the preclinical and clinical approaches for the use of amino acids with and without exercise therapy to improve muscle metabolism in cachexia.
... Aerobic exercise increases the muscle protein synthesis, mitochondrial biogenesis and dynamics, contributes to the restoration of mitochondrial metabolism and reduces the expression of genes involved in catabolism (FOXO3a, MuRF-1, myostatin) [71,72]. In patients with CLD, exercise is considered an important strategy for ameliorating sarcopenia as it prevents skeletal muscle breakdown and maintains physical function [73]. ...
This comprehensive review focuses on the dynamics of branched-chain amino acids (BCAAs) metabolism and its clinical implications in chronic liver disease, with emphasis on the emerging concept of muscle–liver crosstalk. BCAAs, indispensable for protein synthesis and metabolic pathways, undergo unique tissue-specific processing in skeletal muscle and liver. The liver, responsible for amino acid metabolism, plays a distinctive role in sensing BCAAs catabolism, influencing glucose regulation and contributing to the systemic metabolism of BCAAs. Within the context of chronic liver disease, compromised liver metabolism becomes evident through amino acid abnormalities, particularly in the decrease of the Fischer ratio (BCAAs/aromatic amino acids concentrations in plasma). This reduction becomes important in assessing the severity of liver dysfunction due to its associations with adverse outcomes, including increased mortality and complications related to the liver disease. BCAAs supplementation, as explored in this review, emerges as a promising avenue, displaying positive effects on skeletal muscle mass, strength, and overall nutritional status in cirrhosis management. Understanding this interplay offers insights into therapeutic strategies for chronic liver diseases, exploring the way for precision interventions in clinical practice.
... During aging, the body undergoes a series of structural and functional changes in the different physiological systems. In general, progressive aging is associated with biochemical and functional changes in the cells of the musculoskeletal tissue, including the loss of strength and muscle mass, especially type II fibers, and the deterioration of the muscle's oxidative capacity (Harber et al., 2009;Konopka and Harber, 2014). In addition, changes in the cardiovascular and respiratory system result in lower cardiac output and higher blood pressure, causing significant changes in the structure and function of the heart, as well as an alteration of oxygenation and a decrease in ventilation (Lakatta and Levy, 2003;Vigorito and Giallauria, 2014;Alvis and Hughes, 2015). ...
Introduction: There are several tests that provide information about physical fitness and functionality in older adults. The aims of this study were: (i) to analyze the differences between sex and age in functional, strength and cardiorespiratory tests; and (ii) to study the correlations between functional, strength and cardiorespiratory tests according to sex and age.
Methods: A total of 171 older adults (72.09 ± 13.27 kg; 1.59 ± 0.09 m; 72.72 ± 6.05 years) were divided according to sex (men: n = 63; women: n = 108) and age (≥60 <70: n = 65; ≥70 <80: n = 89; ≥80: n = 18). Anthropometry, body composition, upper limb strength (hand grip; HG), lower limb strength (countermovement jump; CMJ), cardiorespiratory capacity (6 min walking test; 6MWT), timed up and go test (TUG) and Short Physical Performance Battery (SPPB) were assessed.
Results: Men showed higher values in CMJ height, HG and expired volume (VE) (p < 0.05). There were no significant differences between sexes in TUG and SPPB. Regarding age, there were significant differences in CMJ, VE and peak oxygen uptake (VO2peak), TUG, gait speed, chair and stand test and SPPB total (p < 0.05). The test times were higher in older people. Regarding correlations, the TUG showed significant correlations in all strength and cardiorespiratory tests, regardless of sex and age. The CMJ correlated more significantly with functional tests compared to HG.
Discussion: There were sex and age differences in functional, strength, and cardiorespiratory tests. The execution of quick and low-cost tests such as the CMJ and TUG could provide information on overall physical fitness in older adults.
... 14 Aerobic exercise training is associated with improved aerobic capacity, cardiovascular function, and metabolic regulation. 15 In patients with CHF, aerobic exercise positively benefits cardiovascular function, myocardial metabolism, and antioxidant status. 16 Additionally, it can effectively reverse ventricular remodeling in heart failure, enhance aerobic capacity, and maximal oxygen absorption. ...
To determine the efficacy and potential protective mechanism of canagliflozin combined with aerobic exercise in treating chronic heart failure (CHF). Isoproterenol was injected into rats to create CHF models. The rats were then subsequently divided into saline, canagliflozin (3 mg/kg/d), aerobic exercise training, and canagliflozin combined with aerobic exercise training. Compared to the CHF group, the canagliflozin combined with the aerobic exercise group had superior ventricular remodeling and cardiac function. In rats treated with canagliflozin combined with aerobic exercise, the expression of cytochrome P450 (CYP) 4A3, CYP4A8, COL1A1, COL3A1, and FN1 was reduced, while the expression of CYP26B1, ALDH1A2, and CYP1A1 increased significantly. Additionally, canagliflozin combined with aerobic exercise decreased the phosphorylation of AKT and ERK1/2. Canagliflozin combined with aerobic exercise has a positive effect on the development of CHF via the regulation of retinol metabolism and the AKT/ERK signaling pathway.
... Exercise plays a pivotal role in addressing and mitigating sarcopenia. Regular physical activity, particularly a combination of resistance training [111,112] and aerobic exercise [113], has been shown to be effective in preventing and treating this condition. Progressive resistance training enhances muscle cross-sectional area and improves handgrip strength and physical function in older adults [112,114]. ...
Sarcopenia, a geriatric syndrome characterized by progressive skeletal muscle mass and function decline, poses a significant health risk among the elderly, contributing to frailty, falls, hospitalization, loss of independence and mortality. The prevalence of sarcopenia varies significantly based on various factors, such as living status, demographics, measurement techniques and diagnostic criteria. Although the overall prevalence is reported at 10% in individuals aged 60 and above, disparities exist across settings, with higher rates in nursing homes and hospitals. Additionally, the differences in prevalence between Asian and non-Asian countries highlight the impact of cultural and ethnic factors, and variations in diagnostic criteria, cut-off values and assessment methods contribute to the observed heterogeneity in reported rates. This review outlines diverse diagnostic criteria and several measurement techniques supporting decision making in clinical practice. Moreover, it facilitates the selection of appropriate tools to assess sarcopenia, emphasizing its multifactorial nature. Various scientific groups, including the European Working Group of Sarcopenia in Older People (EWGSOP), the International Working Group on Sarcopenia (IWGS), the Asian Working Group on Sarcopenia (AWGS), the American Foundation for the National Institutes of Health (FNIH) and the Sarcopenia Definition and Outcomes Consortium (SDOC), have published consensus papers outlining diverse definitions of sarcopenia. The choice of diagnostic criteria should be aligned with the specific objectives of the study or clinical practice, considering the characteristics of the study population and available resources.
... Pain assessment at 3 month 6.0385 ± 1.21592 biochemical adaptations are triggered which causes a physiological stimulus to occur which in turn increase oxygen consumption; oxidation of free fatty acids and circulation of glucose as a source of energy [22,24] and increase the aerobic metabolism, which helps in supplying the energy obligatory for muscle contraction, decreasing weight, reducing obesity and enhancing cardiorespiratory fitness [22,25,26]. Furthermore, a reduction in weight of as little as 5 % from original body weight can restore regular menses and enhance ovulation-inducing reaction and fertility medications [14,27,28]. ...
Background: Polycystic Ovarian Syndrome (PCOS) is the most common genetic disorder of the endocrine gland
among females during the age of reproduction with an estimated prevalence ranging from 2.2 % to 26 %. It is a
typical reason for ovulatory infertility, menstrual dysfunction, and hirsutism. It is a condition in which ovarian
cysts develop with a diameter of between two and nine millimeters on one or each ovaries and therefore there is
an increase in the volume of one is larger than ten millimeters.
Objective: To analyze the effect of pilates on pain and regulation of the menstrual cycle in females with PCOS.
Research methodology: A single centered, quasi-experimental study, performed in Lovely Professional University,
India on a total of 26 participants suffering from PCOS, based on inclusion and exclusion criteria. After a detailed
assessment, the Pilates exercise protocol was given for 3 months i.e. 3 times per week. The readings for pain and
regulation were taken at baseline, at the end of 1st, 2nd, and 3rd month using visual analog scale (VAS)and verbal
multidimensional score sysem (VMSS).
Results: The result findings indicates suggested that there is significant change in the pain (Wilk’s Lambda =.117,
F(3,23) = 58.109, P < 0.05), variable during the menstruation in PCOS over the time of three months. The
menstrual cycles were regularised and the cycle was shifted towards the normal parameters. The VMSS also
shows changes that signify that Pilates is effective in PCOS complications.
Conclusion: This study concluded that Pilates is effective in reducing the pain in PCOS cases which improves the
working ability of the females and also regulates the menstrual cycles which were irregular at the beginning of
the treatment.
... Additionally, exercise induces a complex endocrine interaction network (31). Earlier investigations have demonstrated that acute exercise can swiftly elevate circulating OC levels (32,33), and aerobic exercise, akin to resistance exercise, can augment muscle mass (34). In our study, we stipulated a requirement of completing 10,000 steps per day to mitigate these influences. ...
Objective
Weight reduction often accompanies muscle loss. Existing studies highlight the involvement of osteocalcin (OC) in energy metabolism and its potential to prevent age-related muscle loss. Nevertheless, these studies predominantly involve individuals with hyperglycemia, yielding conflicting research outcomes. This study investigated the protective role of OC against muscle loss during weight reduction in individuals without metabolic syndrome (MetS).
Measures
We enrolled 130 overweight or obese individuals without MetS in a 4-month high-protein, energy-restricted dietary weight management program conducted at two clinic centers. Body composition and laboratory tests were assessed both before and after weight loss. Correlation and regression analysis were made between the changes in metabolic indicators and muscle mass during weight loss.
Results
Following weight loss, there was a decrease in body mass index (BMI), percentage of body fat (PBF), visceral fat area (VFA), fasting insulin (FINS), homeostasis model assessment insulin resistance (HOMA-IR), glycated haemoglobin (HbA1c), and lipid profile, and increase in the percentage of skeletal muscle (PSM) and vitamin D. There was no change in osteocalcin (OC) during the intervention. Correlation analysis of the relative changes in all metabolic indicators revealed a positive correlation between OC and PSM (r=0.383, p=0.002). Multiple linear regression analysis found that OC has a significant protective effect on muscles during weight loss in males after adjusting for confounding factors (β=0.089, p=0.017).
Conclusion
High-protein, energy-restricted diets demonstrate efficacy in enhancing metabolic indicators within the weight-loss population. Furthermore, OC exhibits a protective effect on muscle mass during weight reduction in individuals without MetS, with this effect being particularly evident in males.
... This is similar to the results of previous studies showing that steady exercise reduces body fat [55][56][57][58]. Previous studies have also reported that continuous aerobic exercise not only reduces body fat but also increases muscle strength [59,60]. However, in this study, a significant difference was observed only in percent body fat. ...
This study aimed to verify the effects of prescribed personalized forest walking by considering individuals’ characteristics. To prescribe individualized exercise programs, we developed an algorithm to calculate exercise intensity based on each participant’s age, regular exercise, fatigue level, and chronic disease type, if any. To investigate the effects of forest walking on physical and mental health based on exercise prescription, we recruited 59 participants (average age: 39.1 ± 19.0 years old) aged 18 years or older. Physiological and psychological responses were compared before and after walking in the forest. Systolic blood pressure, diastolic blood pressure, percent body fat, negative affect, and emotional exhaustion significantly decreased, while the pulse rate significantly increased following the forest walking. Additionally, we investigated the effects of exercise relative to successfully maintaining one’s target heart rate and found that these effects were even greater when success score of maintaining the target heart rate while walking improved. Comparison of the groups relative to successfully achieving the target heart rate indicated that the high-achievement group had significant reductions in systolic and diastolic blood pressure, body fat mass, percent body fat, negative affect, and emotional exhaustion, and a significant increase in pulse rate. However, the low-achievement group only showed a significant reduction in emotional exhaustion. This study showed that prescribed forest walking has a positive impact on human health and is expected to have a positive effect on the motivation to start and continue exercising.
... 18,19,20 Resistance training can increase muscle strength and mass. 21,22,23 However, the application of generalized exercise benefits to older adults with anorexia of aging is less clear due to a lack of sufficient evidence. 6,24 Although commonly recommended to older adults with anorexia, the practice of physical exercises did not result in any benefit according to a systematic review. ...
Background
Anorexia of aging is a common geriatric syndrome that includes loss of appetite and/or reduced food intake, with associated undernutrition, unintended weight loss, sarcopenia, functional decline, loss of independence and other adverse health outcomes. Anorexia of aging can have multiple and severe consequences and is often overlooked by healthcare professionals (HCPs). Even more concerningly, clinicians commonly accept anorexia of aging as an inevitable part of ‘normal’ aging. The aim of this assessment was to identify current gaps in professional knowledge and practice in identifying and managing older persons with anorexia. Results may guide educational programmes to fill the gaps identified and therefore improve patient outcomes.
Methods
This international assessment was conducted using a mixed‐methods approach, including focus group interviews with subject matter experts and an electronic survey of practicing HCPs. The assessment was led by the Society on Sarcopenia, Cachexia and Wasting Disorders (SCWD) and was supported by in‐country collaborating organizations.
Results
A quantitative survey of 26 multiple‐choice questions was completed by physicians, dietitians and other HCPs ( n = 1545). Most HCPs (56.8%) recognize a consistent definition of anorexia of aging as a loss of appetite and/or low food intake. Cognitive changes/dementia (91%) and dysphagia (87%) are seen as the biggest risk factors. Most respondents were confident to give nutritional (62%) and physical activity (59.4%) recommendations and engaged caregivers such as family members in supporting older adults with anorexia (80.6%). Most clinicians assessed appetite at each visit (66.7%), although weight is not measured at every visit (41.5%). Apart from the Mini‐Nutritional Assessment Short Form (39%), other tools to screen for appetite loss are not frequently used or no tools are used at all (29.4%). A high number of respondents (38.7%) believe that anorexia is a normal part of aging. Results show that treatment is focused on swallowing disorders (78%), dentition issues (76%) and increasing oral intake (fortified foods [75%] and oral nutritional supplements [74%]). Nevertheless, the lack of high‐quality evidence is perceived as a barrier to optimal treatment (49.2%).
Conclusions
Findings from this international assessment highlight the challenges in the care of older adults with or at risk for anorexia of aging. Identifying professional practice gaps between individual HCPs and team‐based gaps can provide a basis for healthcare education that is addressed at root causes, targeted to specific audiences and developed to improve individual and team practices that contribute to improving patient outcomes.
... remains unclear. From a systematic perspective, the simplest explanation for the mechanism would be aerobic and resistance exercises both promote skeletal muscle hypertrophy (44). Exercise training increases the genetic expression of mitochondria and electron transport chain activities (45), hence an increase in mitochondrial contents in skeletal muscles would be expected to be accompanied by the up-regulation of iNAMPT (24). ...
Objective
Aging is associated with decreased nicotinamide adenine dinucleotide (NAD) levels, which in turn cause dysfunctional mitochondria and indirectly affect a myriad of diseases. Intracellular nicotinamide phosphoribosyltransferase (iNAMPT) serves as a central rate-limiting enzyme in NAD synthesis, making it an indispensable health mediator. This meta-analysis examined the effect of exercise training on the expression of iNAMPT in humans.
Methods
We searched PubMed, Scopus, ClinicalTrials.gov, and the International Clinical Trials Registry Platform for studies published between the inception of the database and July 5, 2023. Using the common-effect model, evidence for the change in iNAMPT following exercise training was synthesized as Cohen’s d.
Results
The search yielded five eligible studies. The overall effect size is 0.81, with a 95% confidence interval of 0.55 to 1.07. Therefore, a random adult will have a 71.7% probability that iNAMPT will be up-regulated following exercise training. In general, exercise training resulted in a 1.46-fold increase in iNAMPT. Our probability statistics indicate that subgroups of interest may differ practically. Specifically, there is a 79.3% probability of increased iNAMPT in men, compared to a 69.0% probability in the overall population; young adults have a 75.6% probability of having an increased iNAMPT, whereas aged adults have a 68.7% probability; and, iNAMPT has a 75.1% probability increase after aerobic exercise and a 66.4% probability increase after resistance exercise.
Conclusion
Exercise training is effective for increasing iNAMPT levels in skeletal muscles. This essential enzyme regulates not only cellular energetics but also healthspan. Therefore, exercise should be promoted as a natural slow-aging lifestyle.
... Physical function Skeletal muscle health and cardiorespiratory fitness (CRF) play a critical role in maintaining mobility, whole-body metabolism, and survival [49][50][51][52][53]. Age-related loss of skeletal muscle mass and CRF increase the risk of disability, loss of independence, and mortality [53][54][55][56]. ...
Treatment with rapamycin, an inhibitor of the mechanistic Target Of Rapamycin Complex One (mTORC1) protein kinase, has been repeatedly demonstrated to extend lifespan and prevent or delay age-related diseases in diverse model systems. Concerns over the risk of potentially serious side effects in humans, including immunosuppression and metabolic disruptions, have cautiously limited the translation of rapamycin and its analogs as a treatment for aging associated conditions. During the last decade, we and others have developed a working model that suggests that while inhibition of mTORC1 promotes healthy aging, many of the negative side effects of rapamycin are associated with “off-target” inhibition of a second mTOR complex, mTORC2. Differences in the kinetics and molecular mechanisms by which rapamycin inhibits mTORC1 and mTORC2 suggest that a therapeutic window for rapamycin could be exploited using intermittent dosing schedules or alternative rapalogs that may enable more selective inhibition of mTORC1. However, the optimal dosing schedules and the long-term efficacy of such interventions in humans are unknown. Here, we highlight ongoing or upcoming clinical trials that will address outstanding questions regarding the safety, pharmacokinetics, pharmacodynamics, and efficacy of rapamycin and rapalogs on several clinically oriented outcomes. Results from these early phase studies will help guide the design of phase 3 clinical trials to determine whether rapamycin can be used safely to inhibit mTORC1 for the treatment and prevention of age-related diseases in humans.
... ST performance is known to result from neuromuscular learning, increased fiber recruitment, muscle cell hypertrophy, and, possibly, hyperplasia without changes in maximal oxygen consumption (VO 2max ) or the ability to generate ATP through oxidative metabolism [17,18]. In aerobic training (AT), increased performance capacity is achieved primarily through increases in VO 2max and the ability of skeletal muscle to generate energy through oxidative metabolism and increased protein synthesis [19][20][21]. We hypothesized that concurrent training (CT), which includes strength-based and aerobic-based exercises in the same training session, promotes positive effects on bone quality that are superior to isolated strength-based and aerobicbased training. ...
A sedentary lifestyle, coupled with a decrease in estrogen, impairs bone homeostasis, favoring to the development of osteopenia and osteoporosis, both recognized as risk factors for fractures. Here, we investigated the quality of the femur, particularly the femur neck region, and the ambulation performance of senescent rats subjected to three different physical training protocols during the periestropause period. Forty-eight female rats, 18 months of age, were subjected to a 120-day training period, three times a week. The rats were distributed into four groups: aerobic training (AT), strength training (ST), concurrent training (CT), or no training (NT). After the experimental period, at 21 months of age, ambulation performance and femur were analyzed using microtomography, Raman stereology, densitometry, and mechanical strength tests. The results demonstrated greater remodeling activity and improvement in resistance and bone microarchitecture in the femur neck of senescent female rats after undergoing physical training. Our verified higher intensities of bands related to collagen, phosphate, amide III, and amide I. Furthermore, the analysis of the secondary collagen structures indicated alterations in the collagen network due to the exercise, resulting in increased bone strength. Both AT and strength-based training proved beneficial, with AT showing greater adaptations in bone density and stiffness in the femur, while strength-based training greater adaptations in trabecular and cortical structure. These insights contribute to the understanding of the potential interventions for preventing osteopenia and osteoporosis, which are critical risk factors for fractures.
... CI confidence interval, SD standard deviation whole-body vibration training, one used high-intensity interval training, and one combined aerobic and resistance exercises. A progressive overload is an effective strategy for inducing muscle hypertrophy using resistance exercise, but not necessarily for other forms of exercise [68,69]. Consequently, additional hypoxia exposure might not be effective to induce muscle hypertrophy for 'non-resistance' exercise modalities. ...
Background
The effects of hypoxia conditioning, which involves recurrent exposure to hypoxia combined with exercise training, on improving body composition in the ageing population have not been extensively investigated.
Objective
This meta-analysis aimed to determine if hypoxia conditioning, compared to similar training near sea level, maximizes body composition benefits in middle-aged and older adults.
Methods
A literature search of PubMed, EMBASE, Web of Science, Scopus and CNKI (China National Knowledge Infrastructure) databases (up to 27th November 2022) was performed, including the reference lists of relevant papers. Three independent reviewers extracted study characteristics and health outcome measures. Search results were limited to original studies of the effects of hypoxia conditioning on body composition in middle-aged and older adults.
Results
Twelve studies with a total of 335 participants were included. Hypoxia conditioning induced greater reductions in body mass index (MD = -0.92, 95%CI: -1.28 to -0.55, I² = 0%, p < 0.00001) and body fat (SMD = -0.38, 95%CI: -0.68 to -0.07, I² = 49%, p = 0.01) in middle-aged and older adults compared with normoxic conditioning. Hypoxia conditioning improved lean mass with this effect not being larger than equivalent normoxic interventions in either middle-aged or older adults (SMD = 0.07, 95%CI -0.12 to 0.25, I² = 0%, p = 0.48). Subgroup analysis showed that exercise in moderate hypoxia (FiO2 > 15%) had larger effects than more severe hypoxia (FiO2 ≤ 15%) for improving body mass index in middle-aged and older adults. Hypoxia exposure of at least 60 min per session resulted in larger benefits for both body mass index and body fat.
Conclusion
Hypoxia conditioning, compared to equivalent training in normoxia, induced greater body fat and body mass index improvements in middle-aged and older adults. Adding hypoxia exposure to exercise interventions is a viable therapeutic solution to effectively manage body composition in ageing population.
Osteoporosis and body composition changes are prevalent musculoskeletal issues contributing to increased risk of frailty in older people. Weight bearing directly influences bone mineral density and body composition. Study aims to determine feasibility of high intensity interval training (HIIT) protocol on body composition parameters and bone mineral density (BMD) in older individuals. Twenty-four participants were randomly allocated to two study groups. The interventional group received supervised HIIT protocol while control group performed non-supervised brisk walking on alternate days over 3 months. Pre- and post-outcome measures were taken at baseline and 3 months which included, BMD using portable densitometer, body composition using a bioelectric impedance analyser, and basic anthropometry. Between group analysis demonstrated the interventional group to be significantly better than control group for all parameters ( ). In conclusion, HIIT protocol is feasible and effective method in improving body composition parameters and BMD in older individuals.
Clinical Trials Registry-India with CTRI number CTRI/2022/01/039740.
This article reviews the historical development of aerobic conditioning. The many physiological effects of aerobic conditioning are presented including the effects on cardiovascular, muscular, and neuromuscular health leading to increased physical endurance and increased lifespan. Aerobic exercise prescription follows the frequency, intensity, time, and type, as well as the volume and progression principles. Frequency recommendations are at least 3 d/wk and 3 to 5 d/wk appears to be conducive to meeting overall physical activity recommendations. Intensity determination is based on several methods that include heart rate methods, ratings of perceived exertion (Borg and OMNI), the talk test, and the counting talk test. Time recommendations include at least 150 to 300 minutes a week of moderate-intensity aerobic activity, 75 to 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activities. Type recommendations include any aerobic activities involving major muscle groups used in a continuous or intermittent manner. Volume recommendations include ≥500 to 1000 metabolic equivalent minutes per week and approximately 150 min/wk of moderate-intensity activity. Progression recommendations include the gradual advancing of the exercise duration, frequency, and intensity, making sure that the progressions allows for the best adherence to aerobic exercise on an ongoing basis. The benefits of aerobic exercise have been shown to be important for every aspect of living a healthy lifestyle across the age span, particularly for aging adults, adults with chronic conditions, and adults with disabilities.
Introduction
Bariatric surgery is a recognized treatment option for severe obesity, and its effectiveness in reducing weight and controlling obesity-related conditions has been demonstrated. However, it can also lead to decreased skeletal muscle mass and strength, increasing the risk of sarcopenia after surgery. This randomized clinical trial studied the effects of a 16-week supervised combined exercise program on sarcopenia in bariatric surgery patients.
Methods
Thirty-seven surgery candidates participated in the EXPOBAR (EXercise POst BARiatric) program and were randomized into experimental or control groups. The intervention lasted 16 weeks, starting one month after surgery, and included a supervised combined aerobic and resistance exercise intervention. The outcomes, including body composition and physical fitness parameters, were assessed at four time points. All participants underwent gastric bypass surgery (RYGB).
Results
The EXPOBAR trial revealed significant and meaningful effects of the exercise intervention on anthropometric indices, such as weight (p = 0.039) and waist circumference (p = 0.010). The EXPOBAR trial also showed that after bariatric surgery, there was a clear decrease in muscle mass, and this loss continued through the duration of follow-up, despite the exercise protocol. The most substantial improvements were observed in physical function and strength metrics (p = 0.005 and p < 0.001, respectively), along with a reduction in fat mass (p = 0.006), indicating the intervention’s effectiveness in enhancing both physical fitness and body composition.
Discussion
Current findings indicate that following an initial decrease due to bariatric surgery, a combined exercise intervention significantly improves functional physical capacity and strength. The exercise program in this study effectively reversed the surgery-induced loss in function and strength, reducing the number of patients at risk of sarcopenia. Physical and functional capacity are crucial noninvasive indicators for diagnosing muscle quality and sarcopenia.
Conclusion
Long-term management of sarcopenia and sarcopenic obesity in bariatric surgery patients requires frequent monitoring of body composition and muscle function. This approach is essential for tracking progress and optimizing treatment strategies over time. This study highlights the importance of integrating structured exercise programs into after bariatric surgery care to mitigate the risk of sarcopenia. Future options include nutritional protein supplementation and changes in the exercise protocol.
Trial registration
: The trial was registered at Clinicaltrials.gov (NCT03497546).
Plyometric exercises represent a typology of aerobic exercises that are used to improve speed, physical resistance and strength. Monitoring strength training and reaction speed has a number of unique difficulties due to differences in physical characteristics and capabilities between athletes and the environment in which they perform. Thanks to this, the analysis, reliability and accuracy of the data provided by new smart technologies based and controlled in the easiest way through smartphones or tablets, can provide us with exact values of the executions.
Sarcopenia typically presents in people older than 65 years with signs and symptoms of low muscle strength and low physical performance, such as falls, feeling weak, walking slowly, difficulty rising from a chair, and loss of weight and muscle mass.
The five-item SARC-F patient questionnaire and assessing gait speed are recommended for screening people for suspected sarcopenia. A SARC-F score ≥4 and/or a low usual gait speed indicate low muscle function. Use hand grip or the sit-stand test to assess muscle strength.
Use imaging, such as computed tomography (CT), magnetic resonance imaging (MRI), or dual x-ray absorptiometry (DXA) to assess muscle quality/quantity. Bioimpedance analysis is another diagnostic option, but is less accurate.
In people with confirmed sarcopenia, initiate an exercise or rehabilitation program that focuses on resistance training and balance exercises, combined with dietary intervention to increase protein intake and improve overall calorie intake and quality.
Chronic alcohol intoxication decreases muscle strength/function and causes mitochondrial dysfunction. Aerobic exercise training improves mitochondrial oxidative capacity and increases muscle mass and strength. Presently, the impact of chronic alcohol on aerobic exercise-induced adaptations was investigated. Female C57BL/6Hsd mice were randomly assigned to one of 4 groups: control sedentary (CON SED; n=26), alcohol sedentary (ETOH SED; n=27), control exercise (CON EX; n=28), and alcohol exercise (ETOH EX; n=25). Exercise mice had running wheel access for 2hrs a day, 7 days a week. All mice were fed either control or alcohol-containing liquid diet. Grip strength testing and EchoMRI were performed before and after the interventions. After 6 weeks, hindlimb muscles were collected for molecular analyses. A subset of mice performed a treadmill run to fatigue (RTF), then abstained from alcohol for 2 weeks and repeated the RTF. Alcohol decreased lean mass and forelimb grip strength compared to control-fed mice. Alcohol blunted the exercise induced increase in muscle mass (plantaris and soleus), type IIa fiber percentage in the plantaris and run time to fatigue. Mitochondrial markers (Citrate synthase activity and Complex I-IV, COXIV and Cytochrome C protein expression), were increased with exercise regardless of ETOH in the gastrocnemius but not tibialis anterior muscle. Two-weeks of alcohol abstinence improved RTF time in ETOH EX but not in ETOH SED. While these data suggest alcohol impairs some exercise-induced adaptations in skeletal muscle, not all were negatively affected, indicating exercise may be a beneficial behavior even while consuming alcohol.
Introduction
It is uncertain whether aerobic exercise in the form of walking contributes to the preservation or increase in total or regional skeletal muscle mass (SMM).
Purpose
To determine the effects of aerobic exercise on total and regional (upper body verses leg SMM) in male (n = 105) and female (n = 133) adults with overweight and obesity.
Methods
A retrospective analysis of data from four randomized controlled trials. Participants included those who completed the given trial (Control, n = 63; Intervention, n = 175), and with complete magnetic resonance imaging (MRI) measured adipose tissue and SMM pre- and post-intervention. Macronutrient intake was assessed for a sub-sample of participants. Supervised exercise was performed by walking on a treadmill for durations ranging from 12 to 24 weeks at intensities between 50 to 75% of VO 2 peak.
Results
All MRI-measured adipose tissue depots were reduced, and cardiorespiratory fitness was increased by aerobic exercise compared to controls ( P < 0.001). Independent of baseline SMM, aerobic exercise was associated with a small reduction (estimated mean difference ± standard error) in whole body SMM (-.310 ± .150 kg, P = 0.039) and upper body SMM (-.273 ± .121 kg, P = 0.025) compared to control. No between group difference was observed for change in leg SMM ( P > .10). A negative association was observed between the relative change in body weight and change in total (R ² 0.37, P < 0.001), upper body (R ² 0.21, P < 0.001) and leg SMM (R ² 0.09, P = 0.701). The SMM to adipose tissue ratio increased in response to aerobic exercise and was positively associated with weight loss ( P < 0.001). Change in SMM was not associated with dietary protein intake ( P > .10).
Conclusions
Aerobic exercise performed while walking preserves, but does not increase, SMM in exercising muscle of adults. Skeletal muscle mass not directly targeted by aerobic exercise may not be maintained.
The risk associated with multiple cancers, cardiovascular disease, diabetes, and all-cause mortality is decreased in individuals who meet the current recommendations for physical activity. Therefore, regular exercise remains a cornerstone in the prevention and treatment of non-communicable diseases. An acute bout of exercise results in the coordinated interaction between multiple tissues to meet the increased energy demand of exercise. Over time, the associated metabolic stress of each individual exercise bout provides the basis for long-term adaptations across tissues, including the cardiovascular system, skeletal muscle, adipose tissue, liver, pancreas, gut, and brain. Therefore, regular exercise is associated with a plethora of benefits throughout the whole body, including improved cardiorespiratory fitness, physical function, and glycemic control. Overall, we summarize the exercise-induced adaptations that occur within multiple tissues and how they converge to ultimately improve cardiometabolic health.
Many adolescents have insufficient physical activity. Regular physical activity from young age can improve health and fitness. Getting regular exercise and eating healthy diet should be encouraged among kids and teenagers to prevent various diseases in adulthood and old age, such as osteoporosis and fractures. When exercising, a prescription is needed that is tailored to each individual abilities. The intensity of exercise will be different for each individual in accordance with their age, physiological function, genetics, economic status, and previous comorbid diseases. There is no standardised exercise prescription proven to increase bone mineral density in adolescents. Based on the above description, a study was conducted on the provision of different intensity exercise and its effect on bone morphology and density. In this study, male Wistar rats, aged 15–16 weeks (body weight ± 250-350 grams; n = 20), were split into 4 groups, namely control group, low intensity exercise group, moderate intensity exercise group, and high intensity exercise group. All groups were receiving intervention for 8 weeks. Then, the rats were sacrificed and the femoral bones were isolated. Femur weight and femur length was checked. Bone density was examined using X-Ray and calculated by statistical tests. Research was conducted in the Central Laboratory, Universitas Padjadjaran. There were significant differences of femur weight between high intensity exercise group and control and low intensity exercise groups (p 0.05). Moderate and high intensity exercises significantly increased femur length as opposed to control and low intensity exercise groups (p 0.05). Bone density was higher in moderate and high intensity exercise groups (p 0.05). Moderate to high intensity exercise can increase bone health, seen from significances of bone morphology analysis and a higher density compared to low intensity exercise.
Bariatric surgery is a treatment for severe obesity with associated pathologies, with proven evidence of its benefits. In addition to the reduction in body fat mass, weight loss associated with bariatric surgery is greatly influenced by the significant reduction in skeletal muscle mass and bone mineral mass, which could negatively affect functional capacity and consequently increase the risk of sarcopenia. The need for prophylactic programs that prevent sarcopenia in bariatric surgery patients seems to be one of the crucial points for the long-term surgical success of bariatric and metabolic surgery. This study aimed to analyze the published literature on the effects of physical exercise on sarcopenia induced by bariatric surgery. We followed the PRISMA checklist for systematic reviews, conducted in Pubmed/Medline, Ebsco, Web of Science, and Scopus databases. Randomized controlled studies, controlled clinical studies, and other experimental studies were considered for inclusion in the study. A total of 356 possibly relevant studies were identified, and 8 studies were included in the review, 6 of which were randomized experimental studies, 1 pilot study, and 1 quasi-experimental study, with quality considered reasonable and good. The practice of structured physical exercise allows significant improvements in body composition, with positive effects on functional capacity, muscle strength, metabolic risk factors, and quality of life in obese patients undergoing bariatric surgery, especially with the combined type of exercise. The studies did not objectively evaluate sarcopenia, but in a complementary way, with analysis of associated parameters and criteria. An individualized and supervised combined exercise program contributes to the reduction of sarcopenia after bariatric surgery.
Background
Many sports require maximal strength and endurance performance. Concurrent strength and endurance training can lead to suboptimal training adaptations. However, how adaptations differ between males and females is currently unknown. Additionally, current training status may affect training adaptations.
Objective
We aimed to assess sex-specific differences in adaptations in strength, power, muscle hypertrophy, and maximal oxygen consumption (V˙O2max) to concurrent strength and endurance training in healthy adults. Second, we investigated how training adaptations are influenced by strength and endurance training status.
Methods
A systematic review and meta-analysis was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and a Cochrane risk of bias was evaluated. ISI Web of science, PubMed/MEDLINE, and SPORTDiscus databases were searched using the following inclusion criteria: healthy adults aged 18–50 years, intervention period of ≥ 4 weeks, and outcome measures were defined as upper- and lower-body strength, power, hypertrophy, and/or V˙O2max. A meta-analysis was performed using a random-effects model and reported in standardized mean differences.
Results
In total, 59 studies with 1346 participants were included. Concurrent training showed blunted lower-body strength adaptations in males, but not in females (male: − 0.43, 95% confidence interval [− 0.64 to − 0.22], female: 0.08 [− 0.34 to 0.49], group difference: P = 0.03). No sex differences were observed for changes in upper-body strength (P = 0.67), power (P = 0.37), or V˙O2max (P = 0.13). Data on muscle hypertrophy were insufficient to draw any conclusions. For training status, untrained but not trained or highly trained endurance athletes displayed lower V˙O2max gains with concurrent training (P = 0.04). For other outcomes, no differences were found between untrained and trained individuals, both for strength and endurance training status.
Conclusions
Concurrent training results in small interference for lower-body strength adaptations in males, but not in females. Untrained, but not trained or highly trained endurance athletes demonstrated impaired improvements in V˙O2max following concurrent training. More studies on females and highly strength-trained and endurance-trained athletes are warranted.
Clinical Trial Registration
PROSPERO: CRD42022370894.
The development of sarcopenia in the elderly is associated with many potential factors and/or processes that impair the renovation and maintenance of skeletal muscle mass and strength as ageing progresses. Among them, a defect by skeletal muscle to respond to anabolic stimuli is to be considered. Common anabolic stimuli/signals in skeletal muscle are hormones (insulin, growth hormones, IGF-1, androgens, and β-agonists such epinephrine), substrates (amino acids such as protein precursors on top, but also glucose and fat, as source of energy), metabolites (such as β-agonists and HMB), various biochemical/intracellular mediators), physical exercise, neurogenic and immune-modulating factors, etc. Each of them may exhibit a reduced effect upon skeletal muscle in ageing. In this article, we overview the role of anabolic signals on muscle metabolism, as well as currently available evidence of resistance, at the skeletal muscle level, to anabolic factors, from both in vitro and in vivo studies. Some indications on how to augment the effects of anabolic signals on skeletal muscle are provided.
Type 2 diabetes mellitus (T2DM) and sarcopenia (low skeletal muscle mass and function) share a bidirectional relationship. The prevalence of these diseases increases with age and they share common risk factors. Skeletal muscle fat infiltration, commonly referred to as myosteatosis, may be a major contributor to both T2DM and sarcopenia in older adults via independent effects on insulin resistance and muscle health. Many strategies to manage T2DM result in energy restriction and subsequent weight loss, and this can lead to significant declines in muscle mass in the absence of resistance exercise, which is also a first-line treatment for sarcopenia. In this review, we highlight recent evidence on established treatments and emerging therapies targeting weight loss and muscle mass and function improvements in older adults with, or at risk of, T2DM and/or sarcopenia. This includes dietary, physical activity and exercise interventions, new generation incretin-based agonists and myostatin-based antagonists, and endoscopic bariatric therapies. We also highlight how digital health technologies and health literacy interventions can increase uptake of, and adherence to, established and emerging treatments and therapies in older adults with T2DM and/or sarcopenia.
Introduction
Exercise improves vascular function, but it is unclear whether benefits are mediated by traditional cardiovascular (CV) risk factors, or whether sex differences in training effects exist in older adults. We hypothesized that exercise would improve CV risk factors, that males and females would benefit similarly, and that improvements in risk factors would correlate with changes in vascular function.
Methods
Seventy-two healthy middle-aged/older adults (age = 62 ± 7, 26%♂) were randomized to a land-walking (LW, n = 23), water-walking (WW, n = 25) or a non-exercise control group (C, n = 23). The exercise groups undertook supervised and monitored training 3 times/week for 50 min per session, across 24 weeks. Blood pressure, body composition (DXA), blood lipids and glucose, and flow mediated brachial artery dilation (FMD) were assessed in all participants at weeks 0 and 24. To maximize power for sex differences and correlation analyses, we pooled the training groups (LW + WW).
Results
Training prevented increases in LDL and TC:HDL ratio observed in C group. No group x time interactions were observed for other risk factors. Sex differences in training effects existed for visceral fat (-187 ± 189 g♂ vs -15 ± 161 g♀; P = 0.006), and lean mass (-352 ± 1045 g♂ vs 601 ± 1178 g♀; P = 0.008). Improvement in FMD was correlated with decreased waist girth ( r = -0.450, P = 0.036), but not with other risk factors.
Conclusions
Exercise training prevented deterioration in lipid levels, whilst sex differences existed for body composition changes with training. Improvement in vascular function was not dependent on changes in risk factors in middle-aged/older adults, suggesting that artery health may be dependent upon other exercise-related stimuli.
Morphometry and oxidative capacity of slow-twitch (type I) and fast-twitch (type IIa and IIb) muscle fibers obtained from vastus lateralis needle biopsies were compared between younger (21-30 yr) and older (51-62 yr) normal fit (maximal O2 uptake = 47.0 vs. 32.3 ml.kg-1.min-1) and endurance-trained (66.3 vs. 52.7 ml.kg-1.min-1) men (n = 6/group). The older groups had smaller type IIa (31%) and IIb (40%) fiber areas and fewer capillaries surrounding these fibers than did younger groups. The reduced type II fiber areas and capillary contacts associated with aging were also observed in the older trained men. However, the capillary supply per unit type II fiber area was not affected by age but was enhanced by training. Additionally, on the basis of quantitative histochemical analysis, succinate dehydrogenase activities of type IIa fibers in the older trained men [4.07 +/- 0.68 (SD) mmol.min-1.l-1] were similar to those observed in younger trained men (4.00 +/- 0.48 mmol.min-1.l-1) and twofold higher than in older normal fit men (2.01 +/- 0.65 mmol.min-1.l-1; age x fitness interaction, P < 0.05). Type I muscle fibers were unaffected by age but were larger and had more capillary contacts and higher succinate dehydrogenase activities in the trained groups. The findings of this study suggest that aging results in a decrease in type II fiber size and oxidative capacity in healthy men and that this latter effect can be prevented by endurance training. Conclusions regarding the effects of age and training status on muscle capillarization depend largely on how these data are expressed.
PGC-1α is a transcriptional coactivator induced by exercise that gives muscle many of the best known adaptations to endurance-type exercise but has no effects on muscle strength or hypertrophy. We have identified a form of PGC-1α (PGC-1α4) that results from alternative promoter usage and splicing of the primary transcript. PGC-1α4 is highly expressed in exercised muscle but does not regulate most known PGC-1α targets such as the mitochondrial OXPHOS genes. Rather, it specifically induces IGF1 and represses myostatin, and expression of PGC-1α4 in vitro and in vivo induces robust skeletal muscle hypertrophy. Importantly, mice with skeletal muscle-specific transgenic expression of PGC-1α4 show increased muscle mass and strength and dramatic resistance to the muscle wasting of cancer cachexia. Expression of PGC-1α4 is preferentially induced in mouse and human muscle during resistance exercise. These studies identify a PGC-1α protein that regulates and coordinates factors involved in skeletal muscle hypertrophy.
Aging is associated with a progressive decline in muscle strength, muscle mass, and aerobic capacity, which reduces mobility
and impairs quality of life in elderly adults. Exercise is commonly employed to improve muscle function in individuals of
all ages; however, chronic aerobic exercise is believed to largely impact cardiovascular function and oxidative metabolism,
with minimal effects on muscle mass and strength. To study the effects of long-term aerobic exercise on muscle strength, we
recruited 74 sedentary (SED) or highly aerobically active (ACT) men and women from within three distinct age groups (young:
20–39 years, middle: 40–64 years, and older: 65–86 years) and tested their aerobic capacity, isometric grip and knee extensor
strength, and dynamic 1 repetition maximum knee extension. As expected, ACT subjects had greater maximal oxygen uptake and
peak aerobic power output compared with SED subjects (p < .05). Grip strength relative to body weight declined with age (p < .05) and was greater in ACT compared with SED subjects in both hands (p < .05). Similarly, relative maximal isometric knee extension torque declined with age (p < .05) and was higher in ACT versus SED individuals in both legs (p < .05). Absolute and relative 1 repetition maximum knee extension declined with age (p < .05) and were greater in ACT versus SED groups (p < .05). Knee extensor strength was associated with a greater amount of leg lean mass in the ACT subjects (p < .05). In summary, long-term aerobic exercise appears to attenuate age-related reductions in muscle strength in addition
to its cardiorespiratory and metabolic benefits.
Nutrient stimulation of muscle protein anabolism is blunted with aging and may contribute to the development and progression of sarcopenia in older adults. This is likely due to insulin resistance of protein metabolism and/or endothelial dysfunction with a reduction in nutritive flow, both of which can be improved by aerobic exercise.
Our objective was to determine whether increasing physical activity can enhance the muscle protein anabolic effect of essential amino acid (EAA) + sucrose intake in older subjects by improving nutritive flow and/or insulin signaling.
Using a randomized crossover design, we measured in older subjects [n = 6, 70 ± 3 y of age, BMI (in kg/m2) of 25 ± 1] the acute effects of increasing physical activity with aerobic exercise, as compared with normal sedentary lifestyle, on the response of blood flow, microvascular perfusion, insulin signaling, and muscle protein kinetics to EAA+sucrose intake.
No differences between treatment groups were found in the basal state. The change from the basal state in blood flow, muscle perfusion, phenylalanine delivery, net balance, and muscle protein synthesis during the consumption of EAA+sucrose was significantly higher after the exercise than after the control treatment (P < 0.05). Insulin signaling increased during EAA+sucrose ingestion in both groups (P < 0.05).
Our data indicate that a prior bout of aerobic exercise increases the anabolic effect of nutrient intake in older adults. This effect appears to be mediated by an exercise-induced improvement in nutrient-stimulated vasodilation and nutrient delivery to muscle rather than to improved insulin signaling. This trial was registered at clinicaltrials.gov as NCT00690534.
To assess myosin heavy chain (MHC) plasticity in aging skeletal muscle with aerobic exercise training, MHC composition was measured at the messenger RNA (mRNA) level and protein level in mixed-muscle homogenates and single myofibers. Muscle samples were obtained from eight nonexercising women (70 ± 2 years) before and after 12 weeks of training (20-45 minutes of cycle exercise per session at 60%-80% heart rate reserve, three to four sessions per week). Training elevated MHC I mRNA (p < .10) and protein (p < .05) in mixed-muscle (54% ± 4% to 61% ± 2%) and single myofibers (42% ± 4% to 52% ± 3%). The increase in MHC I protein was positively correlated (p < .05) with improvements in whole muscle power. Training resulted in a general downregulation of MHC IIa and IIx at the mRNA and protein levels. The training-induced increase in MHC I protein and mRNA demonstrates the maintenance of skeletal muscle plasticity with aging. Furthermore, these data suggest that a shift toward an oxidative MHC phenotype may be beneficial for metabolic and functional health in older individuals.
Consuming protein following exercise has been shown to stimulate protein synthesis acutely in skeletal muscle and has been recommended to prevent sarcopenia. It is not known, however, whether acute stimulation persists long term or includes muscle cell division. We asked here whether consuming protein following exercise during aerobic training increases long-term protein and DNA synthesis rates in skeletal muscle of adult humans. Sixteen previously untrained participants (50 ± 8 yr) consumed either a carbohydrate or carbohydrate and protein drink following each session during 6 wk of treadmill training. A younger untrained group provided a nonexercising comparison. Participants were administered heavy water (²H₂O; deuterium oxide) continuously for 6 wk to isotopically label newly synthesized skeletal muscle proteins and DNA. Muscle biopsies were performed after 6 wk of training. Contrary to acute studies, consuming protein after exercise did not increase skeletal muscle protein synthesis rates. In contrast, muscle protein synthesis, DNA, and phospholipid synthesis were significantly higher in the older exercise groups than the younger sedentary group. The higher DNA replication rate could not be attributed to mitochondrial DNA and may be due to satellite cell activation. We conclude that postexercise protein supplementation does not increase rates of mixed protein synthesis over 6 wk and that aerobic exercise may stimulate long-term cell division (DNA synthesis) in skeletal muscle of humans. Measurements of long-term synthesis rates provide important insights into aging and exercise adaptations.
The purpose of this investigation was to assess mixed-muscle fractional synthesis rate (FSR) and the expression of genes involved in skeletal muscle remodeling after aerobic exercise in the fasted and fed states. Eight recreationally active males (25 ± 1 yr; Vo(2 max): 52 ± 2 ml·kg(-1)·min(-1)) performed 60-min of cycle ergometry at 72 ± 1% Vo(2 max) on two occasions in a counter-balanced design. Subjects ingested a noncaloric placebo (EX-FAST) or a beverage containing (per kg body wt): 5 kcal, 0.83 g carbohydrate, 0.37 g protein, and 0.03 g fat (EX-FED) immediately and 1 h after exercise. FSR was assessed at rest and following exercise with the use of a l-[ring (2)H(5)]-phenylalanine infusion combined with muscle biopsies at 2 and 6 h postexercise. mRNA expression was assessed at 2 and 6 h postexercise via real-time RT-PCR. FSR was higher (P < 0.05) after exercise in both EX-FAST (0.112 ± 0.010%·h(-1)) and EX-FED (0.129 ± 0.014%·h(-1)) compared with rest (0.071 ± 0.005%·h(-1)). Feeding attenuated the mRNA expression (P < 0.05) of proteolytic factors MuRF-1 (6 h) and calpain-2 (2 and 6 h) postexercise but did not alter FOXO3A, calpain-1, caspase3, or myostatin mRNA expression compared with EX-FAST. Myogenic regulatory factor (MRF4) mRNA was also attenuated (P < 0.05) at 2 and 6 h postexercise in EX-FED compared with EX-FAST. These data demonstrate that a nonexhaustive bout of aerobic exercise stimulates skeletal muscle FSR in the fasted state and that feeding does not measurably enhance FSR between 2 and 6 h after aerobic exercise. Additionally, postexercise nutrient intake attenuates the expression of factors involved in the ubiquitin-proteosome and Ca(2+)-dependent protein degradation pathways. These data provide insight into the role of feeding on muscle protein metabolism during recovery from aerobic exercise.
We have recently shown that 12 weeks of progressive aerobic exercise training improves whole-muscle size and function in older women. The purpose of this investigation was to evaluate molecular markers that may be associated with muscle hypertrophy after aerobic training in aging skeletal muscle.
Muscle biopsies were obtained before and after 12 weeks of aerobic exercise training on a cycle ergometer in nine older women (70 ± 2 years) to determine basal levels of messenger RNA and protein content of select myogenic, proteolytic, and mitochondrial factors.
The training program increased (p < .05) aerobic capacity 30 ± 9%, whole-muscle cross-sectional area 11 ± 2%, and whole-muscle force production 29 ± 8%. Basal messenger RNA levels of FOXO3A, myostatin, HSP70, and MRF4 were lower (p < .05) after aerobic training. FOXO3A, FOXO3A phosphorylation, and HSP70 protein content were unaltered after training. Mitochondrial protein COX IV was elevated (p < .05) 33 ± 7% after aerobic training, whereas PGC-1α protein content was 20 ± 5% lower (p < .05).
These data suggest that reductions in FOXO3A and myostatin messenger RNA are potentially associated with exercise-induced muscle hypertrophy. Additionally, it appears that mitochondrial biogenesis can occur with aerobic training in older women independent of increased PGC-1α protein. Aerobic exercise training alters molecular factors related to the regulation of skeletal muscle, which supports the beneficial role of aerobic training for improving muscle health in older women.
Age-related skeletal muscle loss is thought to stem from suboptimal nutrition and resistance to anabolic stimuli. Impaired microcirculatory (nutritive) blood flow may contribute to anabolic resistance by reducing delivery of amino acids to skeletal muscle. In this study, we employed contrast-enhanced ultrasound, microdialysis sampling of skeletal muscle interstitium, and stable isotope methodology, to assess hemodynamic and metabolic responses of older individuals to endurance type (walking) exercise during controlled amino acid provision. We hypothesized that older individuals would exhibit reduced microcirculatory blood flow, interstitial amino acid concentrations, and amino acid transport when compared with younger controls. We report for the first time that aging induces anabolic resistance following endurance exercise, manifested as reduced (by ∼40%) efficiency of muscle protein synthesis. Despite lower (by ∼40-45%) microcirculatory flow in the older than in the younger participants, circulating and interstitial amino acid concentrations and phenylalanine transport into skeletal muscle were all equal or higher in older individuals than in the young, comprehensively refuting our hypothesis that amino acid availability limits postexercise anabolism in older individuals. Our data point to alternative mediators of age-related anabolic resistance and importantly suggest correction of these impairments may reduce requirements for, and increase the efficacy of, dietary protein in older individuals.
Overexpression of the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha), like exercise, increases mitochondrial content and inhibits muscle atrophy. To understand these actions, we tested whether PGC-1alpha or its close homolog, PGC-1beta, influences muscle protein turnover. In myotubes, overexpression of either coactivator increased protein content by decreasing overall protein degradation without altering protein synthesis rates. Elevated PGC-1alpha or PGC-1beta also prevented the acceleration of proteolysis induced by starvation or FoxO transcription factors and prevented the induction of autophagy and atrophy-specific ubiquitin ligases by a constitutively active FoxO3. In mouse muscles, overexpression of PGC-1beta (like PGC-1alpha) inhibited denervation atrophy, ubiquitin ligase induction, and transcription by NFkappaB. However, increasing muscle PGC-1alpha levels pharmacologically by treatment of mice with 5-aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside failed to block loss of muscle mass or induction of ubiquitin ligases upon denervation atrophy, although it prevented loss of mitochondria. This capacity of PGC-1alpha and PGC-1beta to inhibit FoxO3 and NFkappaB actions and proteolysis helps explain how exercise prevents muscle atrophy.
This investigation examined Akt-FOXO3A signaling in young women (YW) and old women (OW) before and after 12 weeks of high-intensity resistance training. Muscle biopsies were taken from the vastus lateralis before and immediately after resistance exercise (RE) in the untrained and trained states. In response to RE in YW and OW, phospho Akt Thr308 increased in untrained and trained states, with no change on Ser473 site. FOXO3A-Ser253 site was dephosphorylated in untrained state among YW and OW, and nuclear phospho-FOXO3A increased mainly in YW in trained state. In the basal state, OW displayed lower cytosolic phospho-FOXO3A before training, higher total nuclear FOXO3A, and a trend for higher nuclear-to-cytosolic FOXO3A ratio versus YW after 12 weeks. Basal level MuRF-1 and myostatin mRNA decreased in YW, while OW increased myostatin mRNA after 12-weeks. These data suggest that FOXO3A signaling and FOXO3A-related target gene expression are altered in OW and may partially explain the attenuated training adaptations previously reported in these octogenarian women.
Recent evidence suggests aerobic exercise may help preserve soleus muscle mass during unloading. The purpose of this investigation was to examine the muscle-specific metabolic response to running as it relates to muscle growth. Mixed-muscle protein synthesis [fractional synthetic rate (FSR)] and gene expression (GE) were examined in the vastus lateralis (VL) and soleus (SOL) muscles from eight men (26 +/- 2 yr; Vo(2max) 63 +/- 2 ml.kg(-1).min(-1)) before and after a 45-min level-grade treadmill run at 77 +/- 1% intensity. Muscle glycogen utilization was similar between muscles. Resting FSR was similar between the VL (0.080 +/- 0.007 %/h) and SOL (0.086 +/- 0.008 %/h) and was higher (P < 0.05) 24 h postexercise compared with rest for both muscles. The absolute change in FSR was not different between muscles (0.030 +/- 0.007 vs. 0.037 +/- 0.012 %/h for VL and SOL). At baseline, myostatin GE was approximately twofold higher (P < 0.05) in SOL compared with VL, while no other muscle-specific differences in GE were present. After running, myostatin GE was suppressed (P < 0.05) in both muscles at 4 h and was higher (P < 0.05) than baseline at 24 h for VL only. Muscle regulatory factor 4 mRNA was elevated (P < 0.05) at 4 h in both SOL and VL; MyoD and peroxisome-proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) were higher (P < 0.05) at 4 h, and forkhead box [FOXO]3A was higher at 24 h in SOL only, while muscle-RING-finger protein-1 (MuRF-1) was higher (P < 0.05) at 4 h in VL only. Myogenin and atrogin-1 GE were unaltered. The similar increases between muscles in FSR support running as part of the exercise countermeasure to preserve soleus mass during unloading. The subtle differences in GE suggest a potential mechanism for muscle-specific adaptations to chronic run training.
To examine the effects of aging on human skeletal muscle, 10 men and 10 women, 64 +/- 1 yr old (Mean +/- SE), and 10 men and 10 women, 24 +/- 1 yr old, were studied. All subjects were sedentary nonsmokers who were carefully screened for latent cardiovascular, metabolic, or musculoskeletal disease. Needle biopsy samples were obtained from the lateral gastrocnemius muscle and examined using histochemical and biochemical techniques. The percentage of Type I, Type IIa, and Type IIb fibers did not differ with age. However, Type I fibers occupied a larger percent of total muscle area in the older men and women (60.6 +/- 2.6 vs 53.6 +/- 2.0%; p less than .05), because Type IIa and Type IIb fibers were 13-31% smaller (p less than .001) in these subjects. Muscle capillarization and mitochondrial enzyme (i.e., succinate dehydrogenase, citrate synthase, and beta-hydroxyacyl-CoA dehydrogenase) activities were also approximately 25% lower (p less than .001-.05) in the old subjects. Although it is difficult to determine whether these differences are due to aging itself or are simply due to inactivity, these structural and biochemical changes probably contribute to the decreases in muscle mass, strength, and endurance often observed in healthy but sedentary older men and women.
Previous studies of endurance exercise training in older men and women generally have found only minimal skeletal muscle adaptations to training. To evaluate the possibility that this may have been due to an inadequate training stimulus, we studied 23 healthy older (64 +/- 3 yr) men and women before and after they had trained by walking/jogging at 80% of maximal heart rate for 45 min/day 4 days/wk for 9-12 mo. This training program resulted in a 23% increase in maximal O2 consumption. Needle biopsy samples of the lateral gastrocnemius muscle were obtained before and after training and analyzed for selected histochemical and enzymatic characteristics. The percentage of type I muscle fibers did not change with training. The percentage of type IIb fibers, however, decreased from 19.1 +/- 9.1 to 15.1 +/- 8.1% (P less than 0.001), whereas the percentage of type IIa fibers increased from 22.1 +/- 7.7 to 29.6 +/- 9.1% (P less than 0.05). Training also induced increases in the cross-sectional area of both type I (12%; P less than 0.001) and type IIa fibers (10%; P less than 0.05). Capillary density increased from 257 +/- 43 capillaries/mm2 before training to 310 +/- 48 capillaries/mm2 after training (P less than 0.001) because of increases in the capillary-to-fiber ratio and in the number of capillaries in contact with each fiber. Lactate dehydrogenase activity decreased by 21% (P less than 0.001), whereas the activities of the mitochondrial enzymes succinate dehydrogenase, citrate synthase, and beta-hydroxyacyl-CoA dehydrogenase increased by 24-55% in response to training (P less than 0.001-0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
In an effort to further examine the specificity of training concept, six female student volunteers (mean age=25.3 years) were endurance trained three times a week for a period of twelve weeks. The training consisted of thirty minutes of continuous running per workout. Identical test batteries were administered prior to (pre) and immediately following (post) the treatment period. Each battery of tests consisted of three measures of muscular leg power (vertical jump test, 18-29 m sprint, and the Margaria Step Test), and two measures of cardiovascular endurance (Cooper's 12 minute run, and V˚O2 max during treadmill running). A muscle biopsy from the lateral aspect of the gastrocnemius muscle was also included. The biopsy specimens were stained for myosin ATPase. Percentages of fast twitch (FT) and slow twitch (ST) muscle fibres as well as mean individual FT and ST fibre areas were determined. The training produced significant changes in the exercising subjects for thel2-minute run (p=0.006)and VO2max(p=0.003). No changes were found in the tests of muscular power or individual fibre areas. These data indicate that the endurance training program was of sufficient intensity to effect an increase in cardiovascular fitness. However, these improvements in endurance were not accompanied by any significant changes in muscular leg power or individual muscle fibre size.
This study examined changes in myostatin gene expression in response to strength training (ST). Fifteen young and older men (n = 7) and women (n = 8) completed a 9-week heavy-resistance unilateral knee extension ST program. Muscle biopsies were obtained from the dominant vastus lateralis before and after ST. In addition to myostatin mRNA levels, muscle volume and strength were measured. Total RNA was reverse transcribed into cDNA, and myostatin mRNA was quantified using quantitative PCR by standard fluorescent chemistries and was normalized to 18S rRNA levels. A 37% decrease in myostatin expression was observed in response to ST in all subjects combined (2.70 +/- 0.36 vs 1.69 +/- 0.18 U, arbitrary units; P < 0.05). Though the decline in myostatin expression was similar regardless of age or gender, the small number of subjects in these subgroups suggests that this observation needs to be confirmed. No significant correlations were observed between myostatin expression and any muscle strength or volume measure. Although further work is necessary to clarify the findings, these data demonstrate that myostatin mRNA levels are reduced in response to heavy-resistance ST in humans.
This study assessed variability in muscle size and strength changes in a large cohort of men and women after a unilateral resistance training program in the elbow flexors. A secondary purpose was to assess sex differences in size and strength changes after training.
Five hundred eighty-five subjects (342 women, 243 men) were tested at one of eight study centers. Isometric (MVC) and dynamic strength (one-repetition maximum (1RM)) of the elbow flexor muscles of each arm and magnetic resonance imaging (MRI) of the biceps brachii (to determine cross-sectional area (CSA)) were assessed before and after 12 wk of progressive dynamic resistance training of the nondominant arm.
Size changes ranged from -2 to +59% (-0.4 to +13.6 cm), 1RM strength gains ranged from 0 to +250% (0 to +10.2 kg), and MVC changes ranged from -32 to +149% (-15.9 to +52.6 kg). Coefficients of variation were 0.48 and 0.51 for changes in CSA (P = 0.44), 1.07 and 0.89 for changes in MVC (P < 0.01), and 0.55 and 0.59 for changes in CSA (P < 0.01) in men and women, respectively. Men experienced 2.5% greater gains for CSA (P < 0.01) compared with women. Despite greater absolute gains in men, relative increases in strength measures were greater in women versus men (P < 0.05).
Men and women exhibit wide ranges of response to resistance training, with some subjects showing little to no gain, and others showing profound changes, increasing size by over 10 cm and doubling their strength. Men had only a slight advantage in relative size gains compared with women, whereas women outpaced men considerably in relative gains in strength.
We investigated the effects of endurance training on satellite cells, which are a major component of the regenerative capacity of muscles. Muscle biopsies were obtained from the vastus lateralis of 11 men aged between 70 and 80 years who trained for 14 weeks (work load corresponding to 65-95% of peak oxygen consumption, VO(2) peak). Satellite cells were identified by immunohistochemistry. There was a significant increase in satellite cell number. Additionally, VO(2) peak, citrate synthase activity, and the area of type IIA fibers were significantly increased. Fiber type distribution and the myonuclear number were not significantly affected. The enhancement of satellite cell frequency and fiber area indicate that endurance training is an efficient strategy to improve muscle function in the elderly.
Muscle protein metabolism is resistant to insulin's anabolic effect in healthy older subjects. This is associated with reduced insulin vasodilation. We hypothesized that aerobic exercise restores muscle protein anabolism in response to insulin by improving vasodilation in older subjects. We measured blood flow, endothelin-1, Akt/mammalian target of rapamycin (mTOR) signaling, and muscle protein kinetics in response to physiological local hyperinsulinemia in two groups of older subjects following a bout of aerobic exercise (EX group: aged 70 +/- 2 years; 45-min treadmill walk, 70% heart rate max) or rest (CTRL group: aged 68 +/- 1 years). Baseline endothelin-1 was lower and blood flow tended to be higher in the EX group, but protein kinetics was not different between groups. Insulin decreased endothelin-1 (P < 0.05) in both groups, but endothelin-1 remained higher in the CTRL group (P < 0.05) and blood flow increased only in the EX group (EX group: 3.8 +/- 0.7 to 5.3 +/- 0.8; CTRL group: 2.5 +/- 0.2 to 2.6 +/- 0.2 ml x min(-1) x 100 ml leg(-1)). Insulin improved Akt phosphorylation in the EX group and increased mTOR/S6 kinase 1 phosphorylation and muscle protein synthesis (EX group: 49 +/- 11 to 89 +/- 23; CTRL group: 58 +/- 8 to 57 +/- 12 nmol x min(-1) x 100 ml leg(-1)) in the EX group only (P < 0.05). Because breakdown did not change, net muscle protein balance became positive only in the EX group (P < 0.05). In conclusion, a bout of aerobic exercise restores the anabolic response of muscle proteins to insulin by improving endothelial function and Akt/mTOR signaling in older subjects.
Skeletal muscle atrophy in rodents is associated with increased gene expression of proteolytic markers muscle-RING-finger protein 1 (MuRF-1) and atrogin-1. In humans with age-related muscle atrophy, known as sarcopenia, little is known about these key proteolytic biomarkers. Therefore, the purpose of this investigation was 2-fold: (i) measure messenger RNA (mRNA) expression of proteolytic genes MuRF-1, atrogin-1, forkhead box (FOXO)3A, and tumor necrosis factor-alpha (TNF-alpha) in young and old women at rest, and (ii) measure these proteolytic genes in response to an acute resistance exercise (RE) bout, a known hypertrophic stimulus.
A group of old women (OW: n =6, 85+/-1 years, thigh muscle =89+/-4 cm(2)) and young women (YW: n=8, 23+/-2 years, thigh muscle = 122+/-6 cm(2)) performed three sets of 10 knee extensions at 70% of one-repetition maximum. Muscle biopsies were taken from the vastus lateralis before and 4 hours after RE. Using real-time reverse transcription-polymerase chain reaction (RT-PCR), mRNA was amplified and normalized to GAPDH.
At rest, OW expressed higher mRNA levels of MuRF-1 (p=.04) and FOXO3A (p=.001) compared to YW. In response to RE, there was an age effect (p=.01) in the induction of atrogin-1 (OW: 2.5-fold). Both YW and OW had an induction (p=.001) in MuRF-1 (YW: 3.6-fold; OW: 2.6-fold) with RE.
These data show that the regulation of ubiquitin proteasome-related genes involved with muscle atrophy are altered in very old women (>80 years). This finding is manifested both at rest and in response to RE, which may contribute to the large degree of muscle loss with age.
Resistance (RE) and endurance (EE) exercise stimulate mixed skeletal muscle protein synthesis. The phenotypes induced by RE (myofibrillar protein accretion) and EE (mitochondrial expansion) training must result from differential stimulation of myofibrillar and mitochondrial protein synthesis. We measured the synthetic rates of myofibrillar and mitochondrial proteins and the activation of signalling proteins (Akt-mTOR-p70S6K) at rest and after an acute bout of RE or EE in the untrained state and after 10 weeks of RE or EE training in young healthy men. While untrained, RE stimulated both myofibrillar and mitochondrial protein synthesis, 67% and 69% (P < 0.02), respectively. After training, only myofibrillar protein synthesis increased with RE (36%, P = 0.05). EE stimulated mitochondrial protein synthesis in both the untrained, 154%, and trained, 105% (both P < 0.05), but not myofibrillar protein synthesis. Acute RE and EE increased the phosphorylation of proteins in the Akt-mTOR-p70S6K pathway with comparatively minor differences between two exercise stimuli. Phosphorylation of Akt-mTOR-p70S6K proteins was increased after 10 weeks of RE training but not by EE training. Chronic RE or EE training modifies the protein synthetic response of functional protein fractions, with a shift toward exercise phenotype-specific responses, without an obvious explanatory change in the phosphorylation of regulatory signalling pathway proteins.
Muscle biopsies were obtained from the gastrocnemius of 14 elite distance runners, 18 middle distance runners, and 19 untrained men. The middle distance runners were all highly trained, but had significantly slower performance times than the elite runners at distances greater than 3 miles. Fiber composition and mean cross sectional areas were determined from muscle sections incubated for histochemical activity. A portion of the specimen was used to determine succinate dehydrogenase (SDH), lactate dehydrogenase (LDH) and phosphorylase activities. All subjects were tested for maximal oxygen uptake on a treadmill. As previously demonstrated by others, the elite runners' muscles were characterized by a high percentage (79%) of slow twitch (ST) fibers. On the average, the cross sectional area of their ST fibers was found to be 22% larger than the FT fibers (P<0.05). SDH activity of whole muscle homogenates from elite and middle distance runners was 3.4 and 2.8 fold greater, respectively, than that measured in the untrained men. Since the LDH and phosphorylase activities were similar for the runners and untrained men, it appears that training for distance running has little influence on the enzymes of glycogenolysis.
Perturbations in mitochondrial health may foster age-related losses of aerobic capacity (VO2peak) and skeletal muscle size. However, limited data exist regarding mitochondrial dynamics in aging human skeletal muscle and
the influence of exercise. The purpose of this study was to examine proteins regulating mitochondrial biogenesis and dynamics,
VO2peak, and skeletal muscle size before and after aerobic exercise training in young men (20 ± 1 y) and older men (74 ± 3 y). Exercise-induced
skeletal muscle hypertrophy occurred independent of age, whereas the improvement in VO2peak was more pronounced in young men. Aerobic exercise training increased proteins involved with mitochondrial biogenesis, fusion,
and fission, independent of age. This is the first study to examine pathways of mitochondrial quality control in aging human
skeletal muscle with aerobic exercise training. These data indicate normal aging does not influence proteins associated with
mitochondrial health or the ability to respond to aerobic exercise training at the mitochondrial and skeletal muscle levels.
The loss of skeletal muscle size and function with aging, sarcopenia, may be related, in part, to an age-related muscle protein synthesis impairment. In this review, we discuss to what extent aging affects skeletal muscle protein synthesis and how nutrition and exercise can be strategically employed to overcome age-related protein synthesis impairments and slow the progression of sarcopenia.
This review discusses how aging affects the protein synthesis response of skeletal muscle to nutrition and exercise.
YAN, Z., V.A. LIRA, and N.P. GREENE. Exercise training-induced regulation of mitochondrial quality. Exerc. Sport Sci. Rev., Vol. 40, No. 3, pp. 159-164, 2012. Mitochondria are dynamic organelles in skeletal muscle critical in physical performance and disease. The mitochondrial life cycle spans biogenesis, maintenance, and clearance. Exercise training may promote each of these processes, conferring positive impacts on skeletal muscle contractile and metabolic functions. This review focuses on the regulation of these processes by endurance exercise and discusses potential benefits in health and disease.
Objectives:
To examine the possible influences of age and gender on muscle volume responses to strength training (ST).
Design:
Prospective intervention study.
Setting:
University of Maryland Exercise Science and Wellness Research Laboratories.
Participants:
Eight young men (age 20-30 years), six young women (age 20-30 years), nine older men (age 65-75 years), and ten older women (age 65-75 years).
Intervention:
A 6-month whole-body ST program that exercised all major muscle groups of the upper and lower body 3 days/week.
Measurements:
Thigh and quadriceps muscle volumes and mid-thigh muscle cross-sectional area (CSA) were assessed by magnetic resonance imaging before and after the ST program.
Results:
Thigh and quadriceps muscle volume increased significantly in all age and gender groups as a result of ST (P < .001), with no significant differences between the groups. Modest correlations were observed between both the change in quadriceps versus the change in total thigh muscle volume (r = 0.65; P < .001) and the change in thigh muscle volume versus the change in mid-thigh CSA (r = 0.76, P < .001).
Conclusions:
The results indicate that neither age nor gender affects muscle volume response to whole-body ST. Muscle volume, rather than muscle CSA, is recommended for studying muscle mass responses to ST.
We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 ± 1 yr, 22.6 ± 2.1 kg/m(2); means ± SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 ± 1.8%, 80%-1 = 3.2 ± 0.8%, and 80%-3= 7.2 ± 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.
Evidence suggests that consumption of over-the-counter cyclooxygenase (COX) inhibitors may interfere with the positive effects that resistance exercise training has on reversing sarcopenia in older adults. This study examined the influence of acetaminophen or ibuprofen consumption on muscle mass and strength during 12 wk of knee extensor progressive resistance exercise training in older adults. Thirty-six individuals were randomly assigned to one of three groups and consumed the COX-inhibiting drugs in double-blind placebo-controlled fashion: placebo (67 ± 2 yr; n = 12), acetaminophen (64 ± 1 yr; n = 11; 4 g/day), and ibuprofen (64 ± 1 yr; n = 13; 1.2 g/day). Compliance with the resistance training program (100%) and drug consumption (via digital video observation, 94%), and resistance training intensity were similar (P > 0.05) for all three groups. Drug consumption unexpectedly increased muscle volume (acetaminophen: 109 ± 14 cm(3), 12.5%; ibuprofen: 84 ± 10 cm(3), 10.9%) and muscle strength (acetaminophen: 19 ± 2 kg; ibuprofen: 19 ± 2 kg) to a greater extent (P < 0.05) than placebo (muscle volume: 69 ± 12 cm(3), 8.6%; muscle strength: 15 ± 2 kg), when controlling for initial muscle size and strength. Follow-up analysis of muscle biopsies taken from the vastus lateralis before and after training showed muscle protein content, muscle water content, and myosin heavy chain distribution were not influenced (P > 0.05) by drug consumption. Similarly, muscle content of the two known enzymes potentially targeted by the drugs, COX-1 and -2, was not influenced (P > 0.05) by drug consumption, although resistance training did result in a drug-independent increase in COX-1 (32 ± 8%; P < 0.05). Drug consumption did not influence the size of the nonresistance-trained hamstring muscles (P > 0.05). Over-the-counter doses of acetaminophen or ibuprofen, when consumed in combination with resistance training, do not inhibit and appear to enhance muscle hypertrophy and strength gains in older adults. The present findings coupled with previous short-term exercise studies provide convincing evidence that the COX pathway(s) are involved in the regulation of muscle protein turnover and muscle mass in humans.
The objective of this study was to evaluate the location-specific magnitudes of an exercise intervention on thigh muscle volume and anatomical cross-sectional area, using MRI. Forty one untrained women participated in strength, endurance, or autogenic training for 12 weeks. Axial MR images of the thigh were acquired before and after the intervention, using a T1-weighted turbo-spin-echo sequence (10 mm sections, 0.78 mm in-plane resolution). The extensor, flexor, adductor, and sartorius muscles were segmented between the femoral neck and the rectus femoris tendon. Muscle volumes were determined, and anatomical cross-sectional areas were derived from 3D reconstructions at 10% (proximal-to-distal) intervals. With strength training, the volume of the extensors (+3.1%), flexors (+3.5%), and adductors (+3.9%) increased significantly (P < 0.05) between baseline and follow-up, and with endurance training, the volume of the extensor (+3.7%) and sartorius (+5.1%) increased significantly (P < 0.05). No relevant or statistically significant change was observed with autogenic training. The greatest standardized response means were observed for the anatomical cross-sectional area in the proximal aspect (10-30%) of the thigh and generally exceeded those for muscle volumes. The study shows that MRI can be used to monitor location-specific effects of exercise intervention on muscle cross-sectional areas, with the proximal aspect of the thigh muscles being most responsive.
To comprehensively assess the influence of aerobic training on muscle size and function, we examined seven older women (71 +/- 2 yr) before and after 12 wk of cycle ergometer training. The training program increased (P < 0.05) aerobic capacity by 30 +/- 6%. Quadriceps muscle volume, determined by magnetic resonance imaging (MRI), was 12 +/- 2% greater (P < 0.05) after training and knee extensor power increased 55 +/- 7% (P < 0.05). Muscle biopsies were obtained from the vastus lateralis to determine size and contractile properties of individual slow (MHC I) and fast (MHC IIa) myofibers, myosin light chain (MLC) composition, and muscle protein concentration. Aerobic training increased (P < 0.05) MHC I fiber size 16 +/- 5%, while MHC IIa fiber size was unchanged. MHC I peak power was elevated 21 +/- 8% (P < 0.05) after training, while MHC IIa peak power was unaltered. Peak force (Po) was unchanged in both fiber types, while normalized force (Po/cross-sectional area) was 10% lower (P < 0.05) for both MHC I and MHC IIa fibers after training. The decrease in normalized force was likely related to a reduction (P < 0.05) in myofibrillar protein concentration after training. In the absence of an increase in Po, the increase in MHC I peak power was mediated through an increased (P < 0.05) maximum contraction velocity (Vo) of MHC I fibers only. The relative proportion of MLC(1s) (Pre: 0.62 +/- 0.01; Post: 0.58 +/- 0.01) was lower (P < 0.05) in MHC I myofibers after training, while no differences were present for MLC(2s) and MLC(3f) isoforms. These data indicate that aerobic exercise training improves muscle function through remodeling the contractile properties at the myofiber level, in addition to pronounced muscle hypertrophy. Progressive aerobic exercise training should be considered a viable exercise modality to combat sarcopenia in the elderly population.
1. Five subjects trained for 8 weeks on a bicycle ergometer for an average of 40 min/day, four times a week at a work load requiring 80% of the maximal oxygen uptake ( V̇ O 2 max. ). V̇ O 2 max. determinations were performed, and muscle biopsies from the quadriceps femoris muscle (vastus lateralis) were taken before, as well as repeatedly during, the training period. The muscle biopsies were histochemically stained for fibre‐types (myofibrillar ATPase) and capillaries (amylase‐PAS method), and analysed biochemically for succinate dehydrogenase and cytochrome oxidase activities.
2. The training programme resulted in a 16% increase in V̇ O 2 max. , a 20% increase in capillary density, a 20% increase in mean fibre area, and an approximately 40% increase in the activities of succinate dehydrogenase and cytochrome oxidase.
3. The capillary supply to type I, IIA and IIB fibres, expressed as the mean number of capillaries in contact with each fibre‐type, relative to fibre‐type area, increased equally.
4. The present study shows that endurance training constitutes a powerful stimulus for capillary proliferation in human skeletal muscle.
Little is known about the effects of exercise interventions on the distribution of central and/or intra-abdominal (IA) fat, and until now there were no studies in the elderly. Therefore, in this study we investigated the effects of an intensive 6-month endurance training program on overall body composition (hydrostatic weighing), fat distribution (body circumferences), and specific fat depots (computed tomography [CT]), in healthy young (n = 13; age, 28.2 +/- 2.4 years) and older (n = 15; age, 67.5 +/- 5.8 years) men. At baseline, overall body composition was similar in the two groups, except for a 9% smaller fat free mass in the older men (P less than .05). The thigh and arm circumferences were smaller (P = .001 and P less than .05, respectively), while the waist to hip ratio (WHR) was slightly greater in the older men (0.92 +/- 0.04 v 0.97 +/- 0.04, P less than .01). Compared with the relatively small baseline differences in body composition and circumferences, CT showed the older men to have a twofold greater IA fat depot (P less than .001), 48% less thigh subcutaneous (SC) fat (P less than .01), and 21% less thigh muscle mass (P less than .001). Following endurance (jog/bike) training, both the young (+18%, P less than .001) and the older men (+22%, P less than .001) significantly increased their maximal aerobic power (VO2max). This was associated with small but significant decrements in weight, percent body fat, and fat mass (all P less than .001) only in the older men.(ABSTRACT TRUNCATED AT 250 WORDS)