Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis

Timing of creatine supplementation does not influence gains in unilateral muscle hypertrophy or strength from resistance training in young adults: a within-subject design

BACKGROUND

Creatine supplementation, in close proximity to resistance training sessions, may be an important strategy to augment muscle accretion and strength. The purpose of this study was to examine the effects of creatine supplementation immediately before compared to immediately after unilateral resistance training on hypertrophy and strength.

METHODS

Using a counter-balanced, double-blind, repeated measures within-subject design, ten recreationally active participants (7 males; 3 females; age: 23±5 years; height: 174±9 cm; body mass: 73.5±9.7 kg) were randomized to supplement with creatine monohydrate (0.1 g/kg of body mass) immediately before and placebo immediately after training one side of the body and placebo immediately before and creatine immediately after training the other side of the body on alternate days. Resistance training consisted of elbow flexion and knee extension (3-6 sets at 80% 1-repetition maximum [1-RM]) for 8 weeks. Prior to and following training, muscle thickness (elbow flexors and leg extensors; ultrasonography) and strength (1-RM for the elbow flexors and knee extensors) was assessed.

RESULTS

There was a significant increase over time for muscle thickness, strength, and relative strength (P<0.01), with no differences between creatine ingestion strategies. Total training volume performed was similar between conditions (P=0.56).

CONCLUSIONS

Creatine supplementation, immediately before or immediately after unilateral resistance training, produces similar gains in muscle hypertrophy and strength in young adults.

Lactobacillus plantarum HY7715 Ameliorates Sarcopenia by Improving Skeletal Muscle Mass and Function in Aged Balb/c Mice

Sarcopenia is a loss of muscle mass and function in elderly people and can lead to physical frailty and fall-related injuries. Sarcopenia is an inevitable event of the aging process that substantially impacts a person's quality of life. Recent studies to improve muscle function through the intake of various functional food materials are attracting attention. However, it is not yet known whether probiotics can improve muscle mass and muscle strength and affect physical performance. Lactobacillus plantarum HY7715 (HY7715) is a lactic acid bacteria isolated from kimchi. The present research shows that L. plantarum HY7715 increases physical performance and skeletal muscle mass in 80-week-old aged Balb/c male mice. HY7715 not only induces myoblast differentiation and mitochondrial biogenesis but also inhibits the sarcopenic process in skeletal muscle. In addition, HY7715 recovers the microbiome composition and beta-diversity shift. Therefore, HY7715 has promise as a functional probiotic supplement to improve the degeneration of muscle function that is associated with aging.

Creatine supplementation effect on recovery following exercise-induced muscle damage: A systematic review and meta-analysis of randomized controlled trials

Exercise-induced muscle damage (EIMD) causes increased soreness, impaired function of muscles, and reductions in muscle force. Accumulating evidence suggests the beneficial effects of creatine on EIMD. Nevertheless, outcomes differ substantially across various articles. The main aim of this meta-analysis was to evaluate the effect of creatine on recovery following EIMD. Medline, Embase, Cochrane Library, Scopus, and Google Scholar were systematically searched up to March 2021. The Cochrane Collaboration tool for examining the risk of bias was applied for assessing the quality of studies. Weighted mean difference (WMD), 95% confidence interval (CI), and random-effects model, were applied for estimating the overall effect. Between studies, heterogeneity was examined using the chi-squared and I² statistics. Nine studies met the inclusion criteria. Pooled data showed that creatine significantly reduced creatine kinase (CK) concentration overall (WMD = -30.94; 95% CI: -53.19, -8.69; p = .006) and at three follow-up times (48, 72, and 96 hr) in comparison with placebo. In contrast, effects were not significant in lactate dehydrogenase (LDH) concentration overall (WMD = -5.99; 95% CI: -14.49, 2.50; p = .167), but creatine supplementation leaded to a significant reduction in LDH concentrations in trials with 48 hr measurement of LDH. The current data indicate that creatine consumption is better than rest after diverse forms of damaging and exhaustive exercise or passive recovery. The benefits relate to a decrease in muscle damage indices and improved muscle function because of muscle power loss after exercise. PRACTICAL APPLICATIONS: Creatine supplementation would be effective in reducing the immediate muscle damage that happens <24, 24, 48, 72, and 96 hr post-exercise. In the current meta-analysis, the positive effects of creatine could cause a decrease in CK concentration overall. But, due to high heterogeneity and the medium risk of bias for articles, we suggest that these results are taken into account and the facts are interpreted with caution by the readers.

Prevotella copri increases fat accumulation in pigs fed with formula diets

BACKGROUND

Excessive fat accumulation of pigs is undesirable, as it severely affects economic returns in the modern pig industry. Studies in humans and mice have examined the role of the gut microbiome in host energy metabolism. Commercial Duroc pigs are often fed formula diets with high energy and protein contents. Whether and how the gut microbiome under this type of diet regulates swine fat accumulation is largely unknown.

RESULTS

In the present study, we systematically investigated the correlation of gut microbiome with pig lean meat percentage (LMP) in 698 commercial Duroc pigs and found that Prevotella copri was significantly associated with fat accumulation of pigs. Fat pigs had significantly higher abundance of P. copri in the gut. High abundance of P. copri was correlated with increased concentrations of serum metabolites associated with obesity, e.g., lipopolysaccharides, branched chain amino acids, aromatic amino acids, and the metabolites of arachidonic acid. Host intestinal barrier permeability and chronic inflammation response were increased. A gavage experiment using germ-free mice confirmed that the P. copri isolated from experimental pigs was a causal species increasing host fat accumulation and altering serum metabolites. Colon, adipose tissue, and muscle transcriptomes in P. copri-gavaged mice indicated that P. copri colonization activated host chronic inflammatory responses through the TLR4 and mTOR signaling pathways and significantly upregulated the expression of the genes related to lipogenesis and fat accumulation, but attenuated the genes associated with lipolysis, lipid transport, and muscle growth.

CONCLUSIONS

Taken together, the results proposed that P. copri in the gut microbial communities of pigs fed with commercial formula diets activates host chronic inflammatory responses by the metabolites through the TLR4 and mTOR signaling pathways, and increases host fat deposition significantly. The results provide fundamental knowledge for reducing fat accumulation in pigs through regulating the gut microbial composition. Video Abstract.

Chronic Dialysis Patients Are Depleted of Creatine: Review and Rationale for Intradialytic Creatine Supplementation

There is great need for the identification of new, potentially modifiable risk factors for the poor health-related quality of life (HRQoL) and of the excess risk of mortality in dialysis-dependent chronic kidney disease patients. Creatine is an essential contributor to cellular energy homeostasis, yet, on a daily basis, 1.6–1.7% of the total creatine pool is non-enzymatically degraded to creatinine and subsequently lost via urinary excretion, thereby necessitating a continuous supply of new creatine in order to remain in steady-state. Because of an insufficient ability to synthesize creatine, unopposed losses to the dialysis fluid, and insufficient intake due to dietary recommendations that are increasingly steered towards more plant-based diets, hemodialysis patients are prone to creatine deficiency, and may benefit from creatine supplementation. To avoid problems with compliance and fluid balance, and, furthermore, to prevent intradialytic losses of creatine to the dialysate, we aim to investigate the potential of intradialytic creatine supplementation in improving outcomes. Given the known physiological effects of creatine, intradialytic creatine supplementation may help to maintain creatine homeostasis among dialysis-dependent chronic kidney disease patients, and consequently improve muscle status, nutritional status, neurocognitive status, HRQoL. Additionally, we describe the rationale and design for a block-randomized, double-blind, placebo-controlled pilot study. The aim of the pilot study is to explore the creatine uptake in the circulation and tissues following different creatine supplementation dosages.

The Effect of a Multi-ingredient Supplement on Resistance Training-induced Adaptations

INTRODUCTION

Resistance exercise training (RET) induces muscle hypertrophy that, when combined with co-temporal protein ingestion, is enhanced. However, fewer studies have been conducted when RET is combined with multi-ingredient supplements.

PURPOSE

We aimed to determine the effect of a high-quality multi-ingredient nutritional supplement (SUPP) versus an isonitrogenous (lower protein quality), isoenergetic placebo (PL) on RET-induced gains in lean body mass (LBM), muscle thickness, and muscle cross-sectional area (CSA). We hypothesized that RET-induced gains in LBM and muscle CSA would be greater in SUPP versus PL.

METHODS

In a double-blind randomized controlled trial, 26 (13 male, 13 female) healthy young adults (mean ± SD, 22 ± 2 yr) were randomized to either the SUPP group (n = 13; 20 g whey protein, 2 g leucine, 2.5 g creatine monohydrate, 300 mg calcium citrate, 1000 IU vitamin D) or the PL group (n = 13; 20 g collagen peptides, 1.4 g alanine, 0.6 g glycine) groups, ingesting their respective supplements twice daily. Measurements were obtained before and after a 10-wk linear progressive RET program.

RESULTS

Greater increases in LBM were observed for SUPP versus PL (SUPP: +4.1 ± 1.3 kg, PL: +2.8 ± 1.7 kg, P < 0.05). No additive effect of the supplement could be detected on vastus lateralis muscle CSA, but SUPP did result in increased biceps brachii muscle CSA and thickness (P < 0.05).

CONCLUSIONS

We conclude that when combined with RET, the consumption of SUPP increased LBM and upper-body CSA and thickness to a greater extent than to that observed in the PL group of healthy young adults.

Eat like an athlete: insights of sports nutrition science to support active aging in healthy older adults

Skeletal muscle mass losses with age are associated with negative health consequences, including an increased risk of developing metabolic disease and the loss of independence. Athletes adopt numerous nutritional strategies to maximize the benefits of exercise training and enhance recovery in pursuit of improving skeletal muscle quality, mass, or function. Importantly, many of the principles applied to enhance skeletal muscle health in athletes may be applicable to support active aging and prevent sarcopenia in the healthy (non-clinical) aging population. Here, we discuss the anabolic properties of protein supplementation in addition to ingredients that may enhance the anabolic effects of protein (e.g. omega 3 s, creatine, inorganic nitrate) in older persons. We conclude that nutritional strategies used in pursuit of performance enhancement in athletes are often applicable to improve skeletal muscle health in the healthy older population when implemented as part of a healthy active lifestyle. Further research is required to elucidate the mechanisms by which these nutrients may induce favourable changes in skeletal muscle and to determine the appropriate dosing and timing of nutrient intakes to support active aging.

Efficacy of Dietary and Supplementation Interventions for Individuals with Type 2 Diabetes

The prevalence of Type 2 diabetes (T2D) is increasing, which creates a large economic burden. Diet is a critical factor in the treatment and management of T2D; however, there are a large number of dietary approaches and a general lack of consensus regarding the efficacy of each. Therefore, the purpose of this narrative review is twofold: (1) to critically evaluate the effects of various dietary strategies on diabetes management and treatment, such as Mediterranean diet, plant-based diet, low-calorie and very low-calorie diets, intermittent fasting, low-carbohydrate and very low-carbohydrate diets, and low glycemic diets and (2) to examine several purported supplements, such as protein, branched-chain amino acids, creatine, and vitamin D to improve glucose control and body composition. This review can serve as a resource for those wanting to evaluate the evidence supporting the various dietary strategies and supplements that may help manage T2D.

Supplement-based nutritional strategies to tackle frailty: A multifactorial, double-blind, randomized placebo-controlled trial

BACKGROUND

Sarcopenia plays a central role in the development of frailty syndrome. Nutrition and exercise are cornerstone strategies to mitigate the transition to frailty; however, there is a paucity of evidence for which dietary and exercise strategies are effective.

OBJECTIVE

This large, multifactorial trial investigated the efficacy of different dietary strategies to enhance the adaptations to resistance training in pre-frail and frail elderly.

METHODS

This was a single-site 16-week, double-blind, randomized, placebo-controlled trial conducted at the Clinical Hospital, School of Medicine - University of São Paulo, Sao Paulo, Brazil. Four integrated, sub-investigations were conducted to compare: 1) leucine vs. placebo; 2) whey vs. soy vs. placebo; 3) creatine vs. whey vs. creatine plus whey vs. placebo; 4) women vs. men in response to whey. Sub-investigations 1 to 3 were conducted in women, only. Two-hundred participants (154 women/46 men, mean age 72 ± 6 years) underwent a twice-a-week, resistance training program. The main outcomes were muscle function (assessed by dynamic and isometric strength and functional tests) and lean mass (assessed by DXA). Muscle cross-sectional area, health-related quality of life, bone and fat mass, and biochemical markers were also assessed.

RESULTS

We observed that leucine supplementation was ineffective to improve muscle mass and function. Supplementation with whey and soy failed to enhance resistance-training effects. Similarly, supplementation with neither whey nor creatine potentiated the adaptations to resistance training. Finally, no sex-based differences were found in response to whey supplementation. Resistance exercise per se increased muscle mass and function in all sub-investigations. There were no adverse effects.

CONCLUSION

Neither protein (whey and soy), leucine, nor creatine supplementation enhanced resistance training-induced adaptations in pre-frail and frail elderly, regardless of sex. These findings do not support the notion that some widely used supplement-based interventions can add to the already potent effects of resistance exercise to counteract frailty-related muscle wasting and dynapenia.

CLINICAL TRIAL REGISTRY

NCT01890382; https://clinicaltrials.gov/ct2/show/NCT01890382.

DATA SHARING

Data described in the manuscript will be made available upon request pending application.

Creatine Supplementation: An Update

ABSTRACT

Creatine is a popular and widely used ergogenic dietary supplement among athletes, for which studies have consistently shown increased lean muscle mass and exercise capacity when used with short-duration, high-intensity exercise. In addition to strength gains, research has shown that creatine supplementation may provide additional benefits including enhanced postexercise recovery, injury prevention, rehabilitation, as well as a number of potential neurologic benefits that may be relevant to sports. Studies show that short- and long-term supplementation is safe and well tolerated in healthy individuals and in a number of patient populations.

Impact of Tailored Multicomponent Exercise for Prevent Weakness and Falls on Nursing Home Residents' Functional Capacity

OBJECTIVES

We aimed to determine whether the benefits of long (24 weeks) and short (4 weeks) training programs persisted after short (6 weeks) and long (14 weeks) periods of inactivity in older adult nursing home residents with sarcopenia.

DESIGN

Multicenter randomized trial.

INTERVENTION

The Vivifrail tailored, multicomponent exercise program (http://vivifrail.com) was conducted to individually prescribe exercise for frail older adults, depending on their functional capacity. The training included 4 levels combining strength and power, balance, flexibility, and cardiovascular endurance exercises.

SETTING AND PARTICIPANTS

Twenty-four institutionalized older adults (87.1 ± 7.1 years, 58.3% women) diagnosed with sarcopenia were allocated into 2 groups: the Long Training-Short Detraining (LT-SD) group completed 24 weeks of supervised Vivifrail training followed by 6 weeks of detraining; the Short Training-Long Detraining (ST-LD) group completed 4 weeks of training and 14 weeks of detraining.

MEASURES

Changes in functional capacity and strength were evaluated at baseline, and after short and long training and detraining periods.

RESULTS

Benefits after short and long exercise interventions persisted when compared with baseline. Vivifrail training was highly effective in the short term (4 weeks) in increasing functional and strength performance (effect size = 0.32-1.44, P < .044) with the exception of handgrip strength. Continued training during 24 weeks produced 10% to 20% additional improvements (P < .036). Frailty status was reversed in 36% of participants, with 59% achieving high self-autonomy. Detraining resulted in a 10% to 25% loss of strength and functional capacity even after 24 weeks of training (effects size = 0.24-0.92, P < .039).

CONCLUSIONS AND IMPLICATIONS

Intermittent strategies such as 4 weeks of supervised exercise 3 times yearly with no more than 14 weeks of inactivity between exercise periods appears as an efficient solution to the global challenge of maintaining functional capacity and can even reverse frailty in vulnerable institutionalized older adults.

[Characteristics of resistance training-based programs in older adults with sarcopenia: Scoping review]

OBJECTIVE

The aim of this scoping review was to analyze the resistance training-based programs' characteristics and outcomes of physical and psychological health and cognitive functions measured in older adults with sarcopenia.

METHOD

This scoping review was carried out following the criteria and flow diagram established in the PRISMA guidelines and included studies from 2011 until 2020 from electronic databases, including PubMed, Scopus, and Web of Science.

RESULTS

A total of 13 randomized controlled trials were included. The sample's average age was 72.2 years, with an age range between 71 and 80 years, considering a total sample of 1029 older adults (57% women). Resistance training-based programs were carried out mainly in university facilities, presented high adherence (91.2%) and were able to induce increase in strength and muscle mass. The most frequent parameters used were 2-3 weekly, 50-90-min-long sessions for 3-9 months, using between 8 and 15 repetitions, in an intense training zone with 1-RM between 60% and 85%. The most measured physical health outcomes were muscle strength, muscle mass, and BMI. Cognitive impairment was frequently evaluated, and few studies evaluated mental health.

CONCLUSION

This review characterized resistance training-based programs in older people with sarcopenia, highlighting the extension, frequency, duration, and intensity of these, as well the most frequently used outcome measures and instruments. These results could be useful for prescribing future resistance training-based programs in older adults with sarcopenia.

Meta-Analysis Examining the Importance of Creatine Ingestion Strategies on Lean Tissue Mass and Strength in Older Adults

Creatine supplementation in conjunction with resistance training (RT) augments gains in lean tissue mass and strength in aging adults; however, there is a large amount of heterogeneity between individual studies that may be related to creatine ingestion strategies. Therefore, the purpose of this review was to (1) perform updated meta-analyses comparing creatine vs. placebo (independent of dosage and frequency of ingestion) during a resistance training program on measures of lean tissue mass and strength, (2) perform meta-analyses examining the effects of different creatine dosing strategies (lower: ≤5 g/day and higher: >5 g/day), with and without a creatine-loading phase (≥20 g/day for 5-7 days), and (3) perform meta-analyses determining whether creatine supplementation only on resistance training days influences measures of lean tissue mass and strength. Overall, creatine (independent of dosing strategy) augments lean tissue mass and strength increase from RT vs. placebo. Subanalyses showed that creatine-loading followed by lower-dose creatine (≤5 g/day) increased chest press strength vs. placebo. Higher-dose creatine (>5 g/day), with and without a creatine-loading phase, produced significant gains in leg press strength vs. placebo. However, when studies involving a creatine-loading phase were excluded from the analyses, creatine had no greater effect on chest press or leg press strength vs. placebo. Finally, creatine supplementation only on resistance training days significantly increased measures of lean tissue mass and strength vs. placebo.

Creatine for Exercise and Sports Performance, with Recovery Considerations for Healthy Populations

Creatine is one of the most studied and popular ergogenic aids for athletes and recreational weightlifters seeking to improve sport and exercise performance, augment exercise training adaptations, and mitigate recovery time. Studies consistently reveal that creatine supplementation exerts positive ergogenic effects on single and multiple bouts of short-duration, high-intensity exercise activities, in addition to potentiating exercise training adaptations. In this respect, supplementation consistently demonstrates the ability to enlarge the pool of intracellular creatine, leading to an amplification of the cell's ability to resynthesize adenosine triphosphate. This intracellular expansion is associated with several performance outcomes, including increases in maximal strength (low-speed strength), maximal work output, power production (high-speed strength), sprint performance, and fat-free mass. Additionally, creatine supplementation may speed up recovery time between bouts of intense exercise by mitigating muscle damage and promoting the faster recovery of lost force-production potential. Conversely, contradictory findings exist in the literature regarding the potential ergogenic benefits of creatine during intermittent and continuous endurance-type exercise, as well as in those athletic tasks where an increase in body mass may hinder enhanced performance. The purpose of this review was to summarize the existing literature surrounding the efficacy of creatine supplementation on exercise and sports performance, along with recovery factors in healthy populations.

Nutrition and physical activity interventions for the general population with and without cardiometabolic risk: a scoping review

OBJECTIVE

The objective of this scoping review was to examine the research question: In the adults with or without cardiometabolic risk, what is the availability of literature examining interventions to improve or maintain nutrition and physical activity-related outcomes? Sub-topics included: (1) behaviour counseling or coaching from a dietitian/nutritionist or exercise practitioner, (2) mobile applications to improve nutrition and physical activity and (3) nutritional ergogenic aids.

DESIGN

The current study is a scoping review. A literature search of the Medline Complete, CINAHL Complete, Cochrane Database of Systematic Reviews and other databases was conducted to identify articles published in the English language from January 2005 until May 2020. Data were synthesised using bubble charts and heat maps.

SETTING

Out-patient, community and workplace.

PARTICIPANTS

Adults with or without cardiometabolic risk factors living in economically developed countries.

RESULTS

Searches resulted in 19 474 unique articles and 170 articles were included in this scoping review, including one guideline, thirty systematic reviews (SR), 134 randomised controlled trials and five non-randomised trials. Mobile applications (n 37) as well as ergogenic aids (n 87) have been addressed in several recent studies, including SR. While primary research has examined the effect of individual-level nutrition and physical activity counseling or coaching from a dietitian/nutritionist and/or exercise practitioner (n 48), interventions provided by these practitioners have not been recently synthesised in SR.

CONCLUSION

SR of behaviour counseling or coaching provided by a dietitian/nutritionist and/or exercise practitioner are needed and can inform practice for practitioners working with individuals who are healthy or have cardiometabolic risk.

Nutritional interventions to improve muscle mass, muscle strength, and physical performance in older people: an umbrella review of systematic reviews and meta-analyses

CONTEXT

Sarcopenia is a progressive and generalized skeletal muscle disorder associated with an increased risk of adverse outcomes such as falls, disability, and death. The Belgian Society of Gerontology and Geriatrics has developed evidence-based guidelines for the prevention and treatment of sarcopenia. This umbrella review presents the results of the Working Group on Nutritional Interventions.

OBJECTIVE

The aim of this umbrella review was to provide an evidence-based overview of nutritional interventions targeting sarcopenia or at least 1 of the 3 sarcopenia criteria (ie, muscle mass, muscle strength, or physical performance) in persons aged ≥ 65 years.

DATA SOURCES

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the PubMed and Web of Science databases were searched for systematic reviews and meta-analyses reporting the effect of nutritional supplementation on sarcopenia or muscle mass, strength, or physical performance.

DATA EXTRACTION

Two authors extracted data on the key characteristics of the reviews, including participants, treatment, and outcomes. Methodological quality of the reviews was assessed using the product A Measurement Tool to Assess Systematic Reviews. Three authors synthesized the extracted data and generated recommendations on the basis of an overall synthesis of the effects of each intervention. Quality of evidence was rated with the Grading of Recommendations Assessment, Development and Evaluation approach.

DATA ANALYSIS

A total of 15 systematic reviews were included. The following supplements were examined: proteins, essential amino acids, leucine, β-hydroxy-β-methylbutyrate, creatine, and multinutrient supplementation (with or without physical exercise). Because of both the low amount and the low to moderate quality of the reviews, the level of evidence supporting most recommendations was low to moderate.

CONCLUSIONS

Best evidence is available to recommend leucine, because it has a significant effect on muscle mass in elderly people with sarcopenia. Protein supplementation on top of resistance training is recommended to increase muscle mass and strength, in particular for obese persons and for ≥ 24 weeks. Effects on sarcopenia as a construct were not reported in the included reviews.

Effects of Creatine and Caffeine Supplementation During Resistance Training on Body Composition, Strength, Endurance, Rating of Perceived Exertion and Fatigue in Trained Young Adults

The primary purpose was to determine the separate and combined effects of creatine and caffeine supplementation during resistance training on body composition and muscle performance in trained young adults. Twenty-eight participants were randomized to supplement with creatine and caffeine (CR-CAF; n = 9, 22 ± 4 years; 0.1 g·kg^-1·d^-1 of creatine monohydrate + 3 mg·kg^-1·d^-1 of caffeine anhydrous micronized powder); creatine (CR; n = 7, 22 ± 4 years, 0.1 g·kg^-1·d^-1 of creatine + 3 mg·kg^-1·d^-1 of micronized cellulose), caffeine (CAF; n = 6, 19 ± 1 years, 3 mg·kg^-1·d^-1 of caffeine + 0.1 g·kg^-1·d^-1 of maltodextrin) or placebo (PLA; n = 6, 23 ± 7 years, 0.1 g·kg^-1·d^-1 of maltodextrin + 3 mg·kg^-1·d^-1 micronized cellulose) one hour prior to performing resistance training for 6 weeks. Before and after training and supplementation, fat-free and fat mass (air-displacement plethysmography), muscle thickness (elbow and knee flexors and extensors; ultrasound), muscle strength (1-repetition maximum [1-RM] for the leg press and chest press), and endurance (one set of repetitions to volitional fatigue using 50% baseline 1-RM for leg press and chest press) were assessed. There was a group x time interaction (p = 0.049) for knee extensor muscle thickness with CR experiencing an increase over time with no changes in the other groups. There were no other between group differences for any variable. In conclusion, creatine supplementation and resistance training results in a small improvement in knee extensor muscle accretion in trained young adults.

Creatine Supplementation in Women's Health: A Lifespan Perspective

Despite extensive research on creatine, evidence for use among females is understudied. Creatine characteristics vary between males and females, with females exhibiting 70–80% lower endogenous creatine stores compared to males. Understanding creatine metabolism pre- and post-menopause yields important implications for creatine supplementation for performance and health among females. Due to the hormone-related changes to creatine kinetics and phosphocreatine resynthesis, supplementation may be particularly important during menses, pregnancy, post-partum, during and post-menopause. Creatine supplementation among pre-menopausal females appears to be effective for improving strength and exercise performance. Post-menopausal females may also experience benefits in skeletal muscle size and function when consuming high doses of creatine (0.3 g·kg⁻¹·d⁻¹); and favorable effects on bone when combined with resistance training. Pre-clinical and clinical evidence indicates positive effects from creatine supplementation on mood and cognition, possibly by restoring brain energy levels and homeostasis. Creatine supplementation may be even more effective for females by supporting a pro-energetic environment in the brain. The purpose of this review was to highlight the use of creatine in females across the lifespan with particular emphasis on performance, body composition, mood, and dosing strategies.

The Potential Role of Creatine in Vascular Health

Creatine is an organic compound, consumed exogenously in the diet and synthesized endogenously via an intricate inter-organ process. Functioning in conjunction with creatine kinase, creatine has long been known for its pivotal role in cellular energy provision and energy shuttling. In addition to the abundance of evidence supporting the ergogenic benefits of creatine supplementation, recent evidence suggests a far broader application for creatine within various myopathies, neurodegenerative diseases, and other pathologies. Furthermore, creatine has been found to exhibit non-energy related properties, contributing as a possible direct and in-direct antioxidant and eliciting anti-inflammatory effects. In spite of the new clinical success of supplemental creatine, there is little scientific insight into the potential effects of creatine on cardiovascular disease (CVD), the leading cause of mortality. Taking into consideration the non-energy related actions of creatine, highlighted in this review, it can be speculated that creatine supplementation may serve as an adjuvant therapy for the management of vascular health in at-risk populations. This review, therefore, not only aims to summarize the current literature surrounding creatine and vascular health, but to also shed light onto the potential mechanisms in which creatine may be able to serve as a beneficial supplement capable of imparting vascular-protective properties and promoting vascular health.

Current Evidence and Possible Future Applications of Creatine Supplementation for Older Adults

Sarcopenia, defined as age-related reduction in muscle mass, strength, and physical performance, is associated with other age-related health conditions such as osteoporosis, osteosarcopenia, sarcopenic obesity, physical frailty, and cachexia. From a healthy aging perspective, lifestyle interventions that may help overcome characteristics and associated comorbidities of sarcopenia are clinically important. One possible intervention is creatine supplementation (CR). Accumulating research over the past few decades shows that CR, primarily when combined with resistance training (RT), has favourable effects on aging muscle, bone and fat mass, muscle and bone strength, and tasks of physical performance in healthy older adults. However, research is very limited regarding the efficacy of CR in older adults with sarcopenia or osteoporosis and no research exists in older adults with osteosarcopenia, sarcopenic obesity, physical frailty, or cachexia. Therefore, the purpose of this narrative review is (1) to evaluate and summarize current research involving CR, with and without RT, on properties of muscle and bone in older adults and (2) to provide a rationale and justification for future research involving CR in older adults with osteosarcopenia, sarcopenic obesity, physical frailty, or cachexia.

Factors influencing the efficacy of nutritional interventions on muscle mass in older adults: a systematic review and meta-analysis

CONTEXT

Nutritional interventions stimulate muscle protein synthesis in older adults. To optimize muscle mass preservation and gains, several factors, including type, dose, frequency, timing, duration, and adherence have to be considered.

OBJECTIVE

This systematic review and meta-analysis aimed to summarize these factors influencing the efficacy of nutritional interventions on muscle mass in older adults.

DATA SOURCES

A systematic search was performed using the electronic databases MEDLINE, Embase, CINAHL, Cochrane Central Register of Controlled Trials, and SPORTDiscus from inception date to November 22, 2017, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria included randomized controlled trials, mean or median age ≥65 years, and reporting muscle mass at baseline and postintervention. Exclusion criteria included genetically inherited diseases, anabolic drugs or hormone therapies, neuromuscular electrical stimulation, chronic kidney disease, kidney failure, neuromuscular disorders, and cancer.

DATA EXTRACTION

Extracted data included study characteristics (ie, population, sample size, age, sex), muscle mass measurements (ie, method, measure, unit), effect of the intervention vs the control group, and nutritional intervention factors (ie, type, composition, dose, duration, frequency, timing, and adherence).

DATA ANALYSIS

Standardized mean differences and 95%CIs were calculated from baseline to postintervention. A meta-analysis was performed using a random-effects model and grouped by the type of intervention.

CONCLUSIONS

Twenty-nine studies were included, encompassing 2255 participants (mean age, 78.1 years; SD, 2.22). Amino acids, creatine, β-hydroxy-β-methylbutyrate, and protein with amino acids supplementation significantly improved muscle mass. No effect was found for protein supplementation alone, protein and other components, and polyunsaturated fatty acids. High interstudy variability was observed regarding the dose, duration, and frequency, coupled with inconsistency in reporting timing and adherence. Overall, several nutritional interventions could be effective to improve muscle mass measures in older adults. Because of the substantial variability of the intervention factors among studies, the optimum profile is yet to be established.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42018111306.

Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?

Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine 'loading-phase' required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.

Effects of Nutritional Supplements on Judo-Related Performance: A Review

The potential ergogenic effect of nutritional supplements depends on their dosage and the type of exercise executed. Aiming at reviewing the research literature regarding sport supplements utilized in judo in order to improve performance, a literature search was performed at the following databases: Dialnet, PubMed, Scielo, Scopus and SportDiscus. A total of 11 articles met the inclusion criteria and were selected. Evidence revised indicates that supplementation with caffeine, β-alanine, sodium bicarbonate, creatine, and β-hydroxy-β-methylbutyrate has a positive effect on judo-related performance. Moreover, there is evidence suggesting that combining some of these nutritional supplements may produce an additive effect.

Creatine in Health and Disease

Although creatine has been mostly studied as an ergogenic aid for exercise, training, and sport, several health and potential therapeutic benefits have been reported. This is because creatine plays a critical role in cellular metabolism, particularly during metabolically stressed states, and limitations in the ability to transport and/or store creatine can impair metabolism. Moreover, increasing availability of creatine in tissue may enhance cellular metabolism and thereby lessen the severity of injury and/or disease conditions, particularly when oxygen availability is compromised. This systematic review assesses the peer-reviewed scientific and medical evidence related to creatine's role in promoting general health as we age and how creatine supplementation has been used as a nutritional strategy to help individuals recover from injury and/or manage chronic disease. Additionally, it provides reasonable conclusions about the role of creatine on health and disease based on current scientific evidence. Based on this analysis, it can be concluded that creatine supplementation has several health and therapeutic benefits throughout the lifespan.

Effects of Creatine Supplementation on Properties of Muscle, Bone, and Brain Function in Older Adults: A Narrative Review

Aging is associated with reductions in muscle and bone mass and brain function, which may be counteracted by several lifestyle factors, of which exercise appears to be most beneficial. However, less than 20% of older adults (> 55 years of age) adhere to performing the recommended amount of resistance training (≥ 2 days/week) and less than 12% regularly meet the aerobic exercise guidelines (≥ 150 min/week of moderate to vigorous intensity aerobic exercise) required to achieve significant health benefits. Therefore, from a healthy aging and clinical perspective, it is important to determine whether other lifestyle interventions (independent of exercise) can have beneficial effects on aging muscle quality and quantity, bone strength, and brain function. Creatine, a nitrogen containing organic compound found in all cells of the body, has the potential to have favorable effects on muscle, bone, and brain health (independent of exercise) in older adults. The purpose of this narrative review is to examine and summarize the small body of research investigating the effects of creatine supplementation alone on measures of muscle mass and performance, bone mineral and strength, and indices of brain health in older adults.

Why Are Masters Sprinters Slower Than Their Younger Counterparts? Physiological, Biomechanical, and Motor Control Related Implications for Training Program Design

Elite sprint performances typically peak during an athlete's 20s and decline thereafter with age. The mechanisms underpinning this sprint performance decline are often reported to be strength-based in nature with reductions in strength capacities driving increases in ground contact time and decreases in stride lengths and frequency. However, an as-of-yet underexplored aspect of Masters sprint performance is that of age-related degradation in neuromuscular infrastructure, which manifests as a decline in both strength and movement coordination. Here, the authors explore reductions in sprint performance in Masters athletes in a holistic fashion, blending discussion of strength and power changes with neuromuscular alterations along with mechanical and technical age-related alterations. In doing so, the authors provide recommendations to Masters sprinters-and the aging population, in general-as to how best to support sprint ability and general function with age, identifying nutritional interventions that support performance and function and suggesting useful programming strategies and injury-reduction techniques.

The Additive Effects of Creatine Supplementation and Exercise Training in an Aging Population: A Systematic Review of Randomized Controlled Trials

BACKGROUND AND PURPOSE

The role of creatine supplementation in young athletes and bodybuilders is well established including ergogenic properties of muscular hypertrophy, strength, power, and endurance. Whether the benefits of creatine supplementation translate to an aging population with moderate training stimulus remains unclear especially in regard to gender, creatine dose, and duration. This systematic review assessed whether creatine supplementation combined with exercise results in additive improvements in indices of skeletal muscle, bone, and mental health over exercise alone in healthy older adults.

METHODS

PubMed, CINAHL, and Web of Science databases were utilized to identify randomized controlled trials of creatine supplementation combined with exercise in an aging population with additional predetermined inclusion and exclusion criteria. Two reviewers independently screened the titles and abstracts, reviewed full-text articles, and performed quality assessments using the Physiotherapy Evidence Database scale.

RESULTS AND DISCUSSION

Seventeen studies were comprehensively reviewed according to categories of strength, endurance, functional capacity, body composition, cognition, and safety. These studies suggest that any additive ergogenic creatine effects on upper and/or lower body strength, functional capacity, and lean mass in an older population would require a continuous and daily low-dose creatine supplementation combined with at least 12 weeks of resistance training. Potential creatine specific increases in regional bone mineral density of the femur are possible but may require at least 1 year of creatine supplementation combined with moderate resistance training, and additional long-term clinical trials are warranted. The limited data suggested no additive effects of creatine over exercise alone on indices of mental health. The beneficial effects of creatine supplementation are more consistent in older women than in men.

CONCLUSIONS

Creatine monohydrate is safe to use in older adults. While creatine in conjunction with moderate- to high-intensity exercise in an aging population may improve skeletal muscle health, additional studies are needed to determine the effective dosing and duration paradigm for potential combined creatine and exercise effects on bone and cognition in older adults.

Nonalcoholic fatty liver disease and sarcopenia: pathophysiological connections and therapeutic implications

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is currently one of the most common liver diseases worldwide. Recent data suggest that loss of skeletal muscle mass and function (i.e. sarcopenia) is highly prevalent and frequently overlooked in NAFLD patients. Experimental and clinical data suggest that the relationship between NAFLD and sarcopenia is pathophysiologically complex and bi-directional and there is a growing interest in unveiling how sarcopenia could influence NAFLD development and progression.

AREAS COVERED

PubMed/MEDLINE was searched for articles related to concomitant occurrence of NAFLD and sarcopenia between January 2013 and April 2020. Areas covered in this review include: (1) updated sarcopenia diagnosis strategy, (2) discussion of current data on pathophysiological connections between NAFLD and sarcopenia, and (3) analysis of current and future therapeutic implications of this knowledge.

EXPERT OPINION

Clinical studies describe a consistent association between NAFLD and sarcopenia, although a cause-effect relation remains to be determined. Active implementation of current diagnosis algorithms and optimized treatment can prevent sarcopenia related complications in subjects with NAFLD. Pathogenic pathways implicated in this relation are multiple and complex, a better understanding of them can provide novel biomarkers and targeted therapies that will hopefully have an important impact in NAFLD management.

Sarcopenia during COVID-19 lockdown restrictions: long-term health effects of short-term muscle loss

The COVID-19 pandemic is an extraordinary global emergency that has led to the implementation of unprecedented measures in order to stem the spread of the infection. Internationally, governments are enforcing measures such as travel bans, quarantine, isolation, and social distancing leading to an extended period of time at home. This has resulted in reductions in physical activity and changes in dietary intakes that have the potential to accelerate sarcopenia, a deterioration of muscle mass and function (more likely in older populations), as well as increases in body fat. These changes in body composition are associated with a number of chronic, lifestyle diseases including cardiovascular disease (CVD), diabetes, osteoporosis, frailty, cognitive decline, and depression. Furthermore, CVD, diabetes, and elevated body fat are associated with greater risk of COVID-19 infection and more severe symptomology, underscoring the importance of avoiding the development of such morbidities. Here we review mechanisms of sarcopenia and their relation to the current data on the effects of COVID-19 confinement on physical activity, dietary habits, sleep, and stress as well as extended bed rest due to COVID-19 hospitalization. The potential of these factors to lead to an increased likelihood of muscle loss and chronic disease will be discussed. By offering a number of home-based strategies including resistance exercise, higher protein intakes and supplementation, we can potentially guide public health authorities to avoid a lifestyle disease and rehabilitation crisis post-COVID-19. Such strategies may also serve as useful preventative measures for reducing the likelihood of sarcopenia in general and in the event of future periods of isolation.

Effect of 12 months of creatine supplementation and whole-body resistance training on measures of bone, muscle and strength in older males

BACKGROUND

The combination of creatine supplementation and resistance training (10-12 weeks) has been shown to increase bone mineral content and reduce a urinary indicator of bone resorption in older males compared with placebo. However, the longer-term effects (12 months) of creatine and resistance training on bone mineral density and bone geometric properties in older males is unknown.

AIM

To assess the effects of 12 months of creatine supplementation and supervised, whole-body resistance training on bone mineral density, bone geometric properties, muscle accretion, and strength in older males.

METHODS

Participants were randomized to supplement with creatine (n = 18, 49-69 years, 0.1 g·kg^-1·d^-1) or placebo (n = 20, 49-67 years, 0.1 g·kg^-1·d^-1) during 12 months of supervised, whole-body resistance training.

RESULTS

After 12 months of training, both groups experienced similar changes in bone mineral density and geometry, bone speed of sound, lean tissue and fat mass, muscle thickness, and muscle strength. There was a trend (p = 0.061) for creatine to increase the section modulus of the narrow part of the femoral neck, an indicator of bone bending strength, compared with placebo. Adverse events did not differ between creatine and placebo.

CONCLUSIONS

Twelve months of creatine supplementation and supervised, whole-body resistance training had no greater effect on measures of bone, muscle, or strength in older males compared with placebo.

Would creatine supplementation augment exercise performance during a low carbohydrate high fat diet?

Low carbohydrate high fat (LCHF) diets are emerging in popularity. Several athletics have adopted LCHF diets in an attempt to improve exercise performance and body composition by enhancing fat utilization. However, these diets impair maximal and supramaximal exercise performance due to limited glycogen stores as well as increasing ratings of perceived exertion (RPE). All of these factors may impact training volume and compliance, leading to less optimal training adaptations over time. In contrast, LCHF diets is an effective strategy for weight and fat mass loss and is beneficial for a variety of metabolic processes. One potential nutritional strategy to off-set the negative aspects of a LCHF is creatine (Cr). Creatine supplementation has been shown to increase muscle power output and reduce the rate of fatigue; thereby allowing individuals to work at a higher intensity for a greater duration. Furthermore, Cr supplementation may positively enhance body composition (gains in muscle mass and possibly aid in fat mass loss). Despite the popularity of both LCHF and creatine supplementation, there is no data available investigating the effects of Cr supplementation on exercise performance and body composition during LCHF diets in humans. We would hypothesize that Cr supplementation may augment exercise performance (anerobic power and strength) during a LCHF diet compared to a LCHF diet and placebo. In addition, combining Cr with a LCHF diet would further increase body fat loss and improve body composition compared to a LCHF diet and/or low-fat diets (LFDs) placebo. Our hypotheses would be under the assumption that total caloric intake and protein intake are matched. Future research is warranted to examine chronic exercise with LCHF diets with and without creatine and compare performance and body composition changes to high carbohydrate diets.

Creatine Supplementation Does Not Influence the Ratio Between Intracellular Water and Skeletal Muscle Mass in Resistance-Trained Men

The authors aimed to compare the effects of creatine (Cr) supplementation combined with resistance training on skeletal muscle mass (SMM), total body water, intracellular water (ICW), and extracellular water (ECW) in resistance-trained men as well as to determine whether the SMM/ICW ratio changes in response to the use of this ergogenic aid. Twenty-seven resistance-trained men received either Cr (n = 14) or placebo (n = 13) over 8 weeks. During the same period, subjects performed two split resistance training routines four times per week. SMM was estimated from appendicular lean soft tissue assessed by dual-energy X-ray absorptiometry. Total body water, ICW, and ECW were determined by spectral bioelectrical impedance. Both groups showed improvements (p < .05) in SMM, total body water, and ICW, with greater values observed for the Cr group compared with placebo. ECW increased similarly in both groups (p < .05). The SMM/ICW ratio did not change in either group (p > .05), whereas the SMM/ECW ratio decreased only in the Cr group (p < .05). A positive correlation was observed (p < .05) between SMM and ICW changes (r = .71). The authors' results suggest that the increase in muscle mass induced by Cr combined with resistance training occurs without alteration of the ratio of ICW to SMM in resistance-trained men.

Comparison of the effect of resistance training on the body compositions of different women groups: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

This study attempts to investigate whether simple resistance training (RT) exerts different effects on the body composition of different women groups.

EVIDENCE ACQUISITION

Relevant articles from PubMed and Web of Science databases were searched and simultaneously screened by two authors. Twenty-three randomized controlled trials are included. The qualities were evaluated by the Cochrane bias risk evaluation tool. Data about sample size, Means and SD of FM, BF %, FFM and MM from original articles were extracted and processed by Reviewer Manager 5.3 software.

EVIDENCE SYNTHESIS

For women with postmenopausal, RT can significantly reduce their BF% and FM, and increase their FFM; while for women with premenopausal, it can only obviously reduce their BF%. RT can significantly reduce the FM and BF% of women with overweight/obese and increase their FFM, however, it has no significant effect on women with non-overweight/obese. RT can substantially and positively affect the FM, BF% and FFM of women with sedentary, and can significantly increase the FFM of women with non-sedentary.

CONCLUSIONS

The effect of RT on women's body composition varies across different subgroups with different physiological characteristics. As a consequence, it is more recommended to use RT as a training method for women with postmenopausal, overweight/obese or sedentary, which can achieve a better effect of improving body composition.

The Evolving Applications of Creatine Supplementation: Could Creatine Improve Vascular Health?

Creatine is a naturally occurring compound, functioning in conjunction with creatine kinase to play a quintessential role in both cellular energy provision and intracellular energy shuttling. An extensive body of literature solidifies the plethora of ergogenic benefits gained following dietary creatine supplementation; however, recent findings have further indicated a potential therapeutic role for creatine in several pathologies such as myopathies, neurodegenerative disorders, metabolic disturbances, chronic kidney disease and inflammatory diseases. Furthermore, creatine has been found to exhibit non-energy-related properties, such as serving as a potential antioxidant and anti-inflammatory. Despite the therapeutic success of creatine supplementation in varying clinical populations, there is scarce information regarding the potential application of creatine for combatting the current leading cause of mortality, cardiovascular disease (CVD). Taking into consideration the broad ergogenic and non-energy-related actions of creatine, we hypothesize that creatine supplementation may be a potential therapeutic strategy for improving vascular health in at-risk populations such as older adults or those with CVD. With an extensive literature search, we have found only four clinical studies that have investigated the direct effect of creatine on vascular health and function. In this review, we aim to give a short background on the pleiotropic applications of creatine, and to then summarize the current literature surrounding creatine and vascular health. Furthermore, we discuss the varying mechanisms by which creatine could benefit vascular health and function, such as the impact of creatine supplementation upon inflammation and oxidative stress.

Stroke and sarcopenia

Purpose of review

to evaluate recent scientific research studies related to the changes in skeletal muscle after stroke and the presence of sarcopenia in stroke survivors to establish its incidence and effects on function.

Recent Findings

Recently published findings on stroke-related sarcopenia are limited. This might be due to changes in the consensus definition of sarcopenia. Sarcopenia in stroke patients is estimated at 14 to 54%. The presence of sarcopenia at the time of a stroke can lead to worse recovery and functional outcomes.

Summary

Presence of sarcopenia prior to a stroke may be more common than suspected and can lead to worse functional recovery. Clinicians should be aware of this to better identify and treat stroke-related sarcopenia. Future research should focus on larger population studies to more accurately establish correlation between stroke and sarcopenia.

Supplement Use in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To assess whether a standardized dietary supplementation can help to decrease postoperative muscle atrophy and/or improve rehabilitation outcomes in patients who underwent anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). MEDLINE, Scopus, and Cochrane Library databases were searched, and articles that examined protein or amino acid, vitamin, or any other type of supplementation in ACLR were reviewed. Two independent reviewers conducted the search using pertinent Boolean operations.

RESULTS

A total of 1818 articles were found after our database search. Ten studies fulfilled our inclusion criteria and only assessed patients undergoing ACLR. Four studies assessed protein-based supplementation. One study assessed creatine as a supplement. Four studies assessed vitamin-based supplementation. One study assessed testosterone supplementation. Protein and amino acid supplementation showed potential benefits; multiple authors demonstrated a combination of improved achievement of rehabilitation benchmarks, graft maturation, muscular hypertrophic response, and peak dynamic muscle strength. When we examined creatine, vitamin, or hormone-based protocols, none demonstrated results, suggesting these factors may attenuate muscle atrophy after surgery. Vitamin C and E demonstrated potentially increased local inflammation in skeletal muscle, which runs contrary to the belief that antioxidant vitamin-based supplementation may decrease the inflammatory response that plays a role in the post injury/operative period.

CONCLUSIONS

Protein-based supplementation may play a role in mitigating muscle atrophy associated with ACLR, as multiple authors demonstrated a combination of improved achievement of rehabilitation benchmarks, thigh hypertrophic response, and peak dynamic muscle strength. However, based on current literature, it is not possible to recommend a specific protein-based supplementation protocol at this time for patients undergoing ACLR. Limited evidence suggests no benefit for creatine, vitamin, or hormone-based protocols.

LEVEL OF EVIDENCE

II, a systematic review of level I-II studies.

Improvements in skeletal muscle fiber size with resistance training are age-dependent in older adults: a systematic review and meta-analysis

As studies examining the hypertrophic effects of resistance training (RT) at the cellular level have produced inconsistent results, we performed a systematic review and meta-analysis to investigate muscle fiber size before and after a structured RT intervention in older adults. A random-effects model was used to calculate mean effect size (ES) and 95% confidence intervals (CI). Thirty-five studies were included (age range: 59.0-88.5 yr), and 44 and 30 effects were used to estimate RT impact on myosin heavy chain (MHC) I and II fiber size. RT produced moderate-to-large increases in MHC I (ES = +0.51, 95%CI +0.31 to +0.71; P < 0.001) and II (ES = +0.81, 95%CI +0.56 to +1.05; P < 0.001) fiber size, with men and women having a similar response. Age was negatively associated with change in muscle fiber size for both fiber types (MHC I: R² = 0.11, β = -0.33, P = 0.002; MHC II: R² = 0.10, β = -0.32, P = 0.04), indicating a less robust hypertrophic response as age increases in older adults. Unexpectedly, a higher training intensity (defined as percentage of one-repetition maximum) was associated with a smaller increase in MHC II fiber size (R² = 15.09%, β = -0.39, P = 0.01). Notably, MHC II fiber subtypes (IIA, IIX, IIAX) were examined less frequently, but RT improved their size. Overall, our findings indicate that RT induces cellular hypertrophy in older adults, although the effect is attenuated with increasing age. In addition, hypertrophy of MHC II fibers was reduced with higher training intensity, which may suggest a failure of muscle fibers to hypertrophy in response to high loads in older adults.

Optimizing Skeletal Muscle Anabolic Response to Resistance Training in Aging

Loss of muscle mass and strength with aging, also termed sarcopenia, results in a loss of mobility and independence. Exercise, particularly resistance training, has proven to be beneficial in counteracting the aging-associated loss of skeletal muscle mass and function. However, the anabolic response to exercise in old age is not as robust, with blunted improvements in muscle size, strength, and function in comparison to younger individuals. This review provides an overview of several physiological changes which may contribute to age-related loss of muscle mass and decreased anabolism in response to resistance training in the elderly. Additionally, the following supplemental therapies with potential to synergize with resistance training to increase muscle mass are discussed: nutrition, creatine, anti-inflammatory drugs, testosterone, and growth hormone (GH). Although these interventions hold some promise, further research is necessary to optimize the response to exercise in elderly patients.

Novel renal biomarkers show that creatine supplementation is safe: a double-blind, placebo-controlled randomized clinical trial

The aim of this study was to evaluate the impact of creatine supplementation (CS) on renal function in young, healthy, and active subjects. We used a randomized, double-blind, placebo-controlled clinical trial as the study design. Thirty-six healthy male university students were recruited and divided into three groups: group placebo, group G3 (3 g/day of CS), and group G5 (5 g/day of CS). To assess renal function, new kidney biomarkers, kidney injury molecule-1 (KIM-1) and monocyte chemoattractant protein-1 (MCP-1), were quantified. Serum albumin, serum creatinine, serum urea, estimated glomerular filtration rate (eGFR), proteinuria, and albuminuria were also measured. All groups were evaluated at two times: prior CS or placebo (pre) and after 35 days on CS or placebo (post). After 35 days of intervention, all characteristics were maintained without significant difference (P > 0.05) between the groups, including serum creatinine, eGFR, and more sensitive kidney biomarker concentrations (KIM-1 and MCP-1). The paired analysis showed that the supplemented groups (G3 and 5G) had increased serum creatinine and decreased eGFR levels (P < 0.05). However, the values were still within the normal reference range. In conclusion, the results of renal function evaluation did not show any difference between the evaluated groups. Increased serum creatinine and decreased eGFR levels in CS groups can be explained by increased creatine stores and metabolism, since creatinine is a by-product of creatine metabolism. These findings indicate that the use of CS at doses of 3 g and 5 g/day for a short period (35 days) is safe and did not impair the kidneys or renal function in young healthy subjects.

Nutritional Supplements to Support Resistance Exercise in Countering the Sarcopenia of Aging

Skeletal muscle plays an indispensable role in metabolic health and physical function. A decrease in muscle mass and function with advancing age exacerbates the likelihood of mobility impairments, disease development, and early mortality. Therefore, the development of non-pharmacological interventions to counteract sarcopenia warrant significant attention. Currently, resistance training provides the most effective, low cost means by which to prevent sarcopenia progression and improve multiple aspects of overall health. Importantly, the impact of resistance training on skeletal muscle mass may be augmented by specific dietary components (i.e., protein), feeding strategies (i.e., timing, per-meal doses of specific macronutrients) and nutritional supplements (e.g., creatine, vitamin-D, omega-3 polyunsaturated fatty acids etc.). The purpose of this review is to provide an up-to-date, evidence-based account of nutritional strategies to enhance resistance training-induced adaptations in an attempt to combat age-related muscle mass loss. In addition, we provide insight on how to incorporate the aforementioned nutritional strategies that may support the growth or maintenance of skeletal muscle and subsequently extend the healthspan of older individuals.

Effects of Creatine Supplementation during Resistance Training Sessions in Physically Active Young Adults

The purpose was to examine the effects of creatine supplementation during resistance training sessions on skeletal muscle mass and exercise performance in physically active young adults. Twenty-two participants were randomized to supplement with creatine (CR: n = 13, 26 ± 4 yrs; 0.0055 g·kg^-1 post training set) or placebo (PLA: n = 9, 26 ± 5 yrs; 0.0055 g·kg^-1 post training set) during six weeks of resistance training (18 sets per training session; five days per week). Prior to and following training and supplementation, measurements were made for muscle thickness (elbow and knee flexors/extensors, ankle plantarflexors), power (vertical jump and medicine ball throw), strength (leg press and chest press one-repetition maximum (1-RM)) and muscular endurance (one set of repetitions to volitional fatigue using 50% baseline 1-RM for leg press and chest press). The creatine group experienced a significant increase (p < 0.05) in leg press, chest press and total body strength and leg press endurance with no significant changes in the PLA group. Both groups improved total body endurance over time (p < 0.05), with greater gains observed in the creatine group. In conclusion, creatine ingestion during resistance training sessions is a viable strategy for improving muscle strength and some indices of muscle endurance in physically active young adults.

Creatine supplementation does not promote additional effects on inflammation and insulin resistance in older adults: A pilot randomized, double-blind, placebo-controlled trial

BACKGROUND

A chronic, low-grade inflammation is commonly present in older adults and has been associated with the onset of age-related chronic diseases. Resistance training (RT) and creatine (CR) supplementation emerged as promising strategies to reduce circulating pro-inflammatory cytokines. This study aimed to investigate the effects of CR supplementation combined with RT on markers of inflammation and insulin resistance in community-dwelling older adults.

METHODS

In a pilot randomized, double-blind, placebo-controlled trial, participants were allocated to one of the following groups: 1) Creatine supplementation and resistance training (CR + RT, n = 13); 2) Placebo and resistance training (PL + RT, n = 14). While engaged in a 12-week RT program, participants from CR + RT group received 5 g/day of CR monohydrate and participants from PL + RT group received the same dose of maltodextrin. At baseline and at week 12, blood samples were collected for glucose, insulin, adiponectin, leptin, interleukin 6, interleukin 10, monocyte chemo-attractant protein-1 and C-reactive protein analysis.

RESULTS

After 12 weeks of intervention, there were no differences between groups in any of the variables analyzed. Monocyte chemoattractant protein-1 was reduced in both groups (CR + RT: -55.66 ± 48.93 pg/mL, p < 0.01, dz = 1.13; PL + RT: -46.52 ± 55.21 pg/mL, p < 0.01, dz = 0.84).

CONCLUSION

Resistance training, regardless of CR supplementation, decreased MCP-1 concentration in older adults.

Ancestral contribution of the muscle-specific creatine kinase (CKM) polymorphism rs4884 in the knee osteoarthritis risk: a preliminary study

INTRODUCTION/OBJECTIVES

Articular cartilage and periarticular muscle tissues are strongly affected during knee osteoarthritis (OA). Creatine kinase (CK) is an enzyme expressed in several tissues, but the isoform CK-MM is specific of skeletal muscle, and its serum concentration is used as a biomarker of muscle damage. Genetic variants of the CKM gene have been associated with various pathologies, but to date, there are no reports of association with OA. Due to the rs4884 polymorphism being well represented in the Mexican population, it is used as an ancestry informative marker; thus, the goal of this preliminary report was to evaluate the association of this polymorphism in primary knee OA Mexican patients.

METHOD

Eighty-seven patients with primary knee OA were compared with 107 healthy controls. Serum CK-MM was determined using the dot blot system, and genotyping was performed using the OpenArray system. Logistic regression models were used to assess the association between the rs4884 polymorphism and OA susceptibility adjusting by gender, age, and body mass index.

RESULTS

There were no significant differences in serum CK-MM values between patients and controls. The GG genotype and the G allele had a higher frequency in the control group compared with the OA group (24.3% vs. 12.6%, OR = 0.34, 95% CI = 0.14-0.84, P = 0.019; and 40.2% vs. 28.2%, OR = 0.51, 95% CI = 0.32-0.82, P = 0.005, respectively).

CONCLUSIONS

Our results suggest a protection role of the rs4884 polymorphism against knee OA development; further studies are required to confirm it. Key Points • CK-MM enzyme catalyzes the conversion of creatine and ATP to create phosphocreatine and ADP; this reaction is reversible. • In tissues that consume ATP rapidly, such as skeletal muscle, the phosphocreatine serves as an important energy reservoir. • During knee OA, peripheral muscle tissues of the joint may be affected. • The rs4884 polymorphism of the CKM gene may participate as a protective factor in the development of OA.

Nutritional Strategies to Offset Disuse-Induced Skeletal Muscle Atrophy and Anabolic Resistance in Older Adults: From Whole-Foods to Isolated Ingredients

Preserving skeletal muscle mass and functional capacity is essential for healthy ageing. Transient periods of disuse and/or inactivity in combination with sub-optimal dietary intake have been shown to accelerate the age-related loss of muscle mass and strength, predisposing to disability and metabolic disease. Mechanisms underlying disuse and/or inactivity-related muscle deterioration in the older adults, whilst multifaceted, ultimately manifest in an imbalance between rates of muscle protein synthesis and breakdown, resulting in net muscle loss. To date, the most potent intervention to mitigate disuse-induced muscle deterioration is mechanical loading in the form of resistance exercise. However, the feasibility of older individuals performing resistance exercise during disuse and inactivity has been questioned, particularly as illness and injury may affect adherence and safety, as well as accessibility to appropriate equipment and physical therapists. Therefore, optimising nutritional intake during disuse events, through the introduction of protein-rich whole-foods, isolated proteins and nutrient compounds with purported pro-anabolic and anti-catabolic properties could offset impairments in muscle protein turnover and, ultimately, the degree of muscle atrophy and recovery upon re-ambulation. The current review therefore aims to provide an overview of nutritional countermeasures to disuse atrophy and anabolic resistance in older individuals.

Supplementation with the Leucine Metabolite β-hydroxy-β-methylbutyrate (HMB) does not Improve Resistance Exercise-Induced Changes in Body Composition or Strength in Young Subjects: A Systematic Review and Meta-Analysis

β-hydroxy-β-methylbutyrate (HMB) is a leucine metabolite that is purported to increase fat-free mass (FFM) gain and performance in response to resistance exercise training (RET). The aim of this systematic review and meta-analysis was to determine the efficacy of HMB supplementation in augmenting FFM and strength gains during RET in young adults. Outcomes investigated were: total body mass (TBM), FFM, fat mass (FM), total single repetition maximum (1RM), bench press (BP) 1RM, and lower body (LwB) 1RM. Databases consulted were: Medical Literature Analysis and Retrieval System Online (Medline), Excerpta Medica database (Embase), The Cumulative Index to Nursing and Allied Health Literature (CINAHL), and SportDiscus. Fourteen studies fit the inclusion criteria; however, 11 were analyzed after data extraction and funnel plot analysis exclusion. A total of 302 participants (18-45 y) were included in body mass and composition analysis, and 248 were included in the strength analysis. A significant effect was found on TBM. However, there were no significant effects for FFM, FM, or strength outcomes. We conclude that HMB produces a small effect on TBM gain, but this effect does not translate into significantly greater increases in FFM, strength or decreases in FM during periods of RET. Our findings do not support the use of HMB aiming at improvement of body composition or strength with RET.

Benefits of Creatine Supplementation for Vegetarians Compared to Omnivorous Athletes: A Systematic Review

Background: Creatine monohydrate is a nutritional supplement often consumed by athletes in anaerobic sports. Creatine is naturally found in most meat products; therefore, vegetarians have reduced creatine stores and may benefit from supplementation. Objective: to determine the effects of creatine supplementation on vegetarians. Data sources: PubMed and SPORTDiscus. Eligibility criteria: Randomized controlled trials (parallel group, cross-over studies) or prospective studies. Participants: Vegetarians. Intervention: Creatine supplementation. Study appraisal and synthesis: A total of 64 records were identified, and eleven full-text articles (covering nine studies) were included in this systematic review. Results: Creatine supplementation in vegetarians increased total creatine, creatine, and phosphocreatine concentrations in vastus lateralis and gastrocnemius muscle, plasma, and red blood cells, often to levels greater than omnivores. Creatine supplementation had no effect on brain levels of phosphocreatine. Creatine supplementation increased lean tissue mass, type II fiber area, insulin-like growth factor-1, muscular strength, muscular endurance, Wingate mean power output, and brain function (memory and intelligence) in vegetarian participants. Studies were mixed on whether creatine supplementation improved exercise performance in vegetarians to a greater extent compared to omnivores. Limitations: Studies that were reviewed had moderate–high risk of bias. Conclusions: Overall, it appears vegetarian athletes are likely to benefit from creatine supplementation.

Novel Insights on Intake of Fish and Prevention of Sarcopenia: All Reasons for an Adequate Consumption

Sarcopenia is defined as a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength and it is diagnosed by measurements of muscle mass, muscle strength, and physical performance. Sarcopenia affects quality of life and is associated with several adverse health effects. Muscle decline is aggravated by a sedentary lifestyle and can be prevented through proper nutrition, together with adequate physical activity. Fish contains biologically active compounds, such as omega-3 polyunsaturated fatty acids, proteins, vitamin D, magnesium, and carnitine, which are able to intervene positively on muscle metabolism. This narrative literature review was performed to evaluate evidence regarding the actual benefit of fish consumption in the prevention of sarcopenia and the positive action on the muscle mass of the biological compounds present in fish. The results demonstrated that fish consumption has a protective and anti-inflammatory function on skeletal muscle and that its biologically active compounds help to maintain good muscle performance, preventing sarcopenia. Considering the nutritional and health benefits, elderly with sarcopenia should consume at least three servings per week of fish in order to have a minimum intake of 4-4.59 g daily of omega 3, and reaching the 50% RDA in Vitamin E and D. High biological value of proteins in 150 g of fish and its high available magnesium (20% of RDA in 150 g of fish) are an added value that could suggest fish as a "functional food" in order to prevent and treat sarcopenia.

Effect of Ten Weeks of Creatine Monohydrate Plus HMB Supplementation on Athletic Performance Tests in Elite Male Endurance Athletes

Creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB) are common ergogenic aids in the field of sports and are frequently used in an isolated way. However, there are a few studies that have investigated the effect of combining both supplements on different variables related to performance, with controversial results. Therefore, the main purpose of this study was to determine the efficacy and the degree of potentiation of 10 weeks of CrM plus HMB supplementation on sports performance, which was measured by an incremental test to exhaustion in elite male traditional rowers. In this placebo-controlled, double-blind trial, 10-week study, participants (n = 28) were randomized to a placebo group (PLG; n = 7), CrM group (0.04 g/kg/day of CrM; n = 7), HMB group (3 g/day of HMB; n = 7) and CrM-HMB group (0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before and after 10 weeks of different treatments, an incremental test was performed on a rowing ergometer to calculate the power that each rower obtained at the anaerobic threshold (WAT), and at 4 mmol (W4) and 8 mmol (W8) of blood lactate concentration. There were no significant differences in WAT and W4 among groups or in body composition. However, it was observed that the aerobic power achieved at W8 was significantly higher in the CrM-HMB group than in the PLG, CrM and HMB groups (p < 0.001; η2p = 0.766). Likewise, a synergistic effect of combined supplementation was found for the sum of the two supplements separately at WAT (CrM-HMBG = 403.19% vs. CrMG+HMBG = 337.52%), W4 (CrM-HMBG = 2736.17% vs. CrMG+HMBG = 1705.32%) and W8 (CrM-HMBG = 1293.4% vs. CrMG+HMBG = 877.56%). In summary, CrM plus HMB supplementation over 10 weeks showed a synergistic effect on aerobic power (measured as WAT, W4, and W8) during an incremental test but had no influence muscle mass.

Effects of high-velocity resistance training and creatine supplementation in untrained healthy aging males

The purpose was to investigate the effects of high-velocity resistance training (HVRT) and creatine supplementation in untrained healthy aging males. Participants were randomized to supplement with creatine (0.1 g·kg−1·day−1 of creatine + 0.1 g·kg−1·day−1 of maltodextrin) or placebo (0.2 g·kg−1·day−1 of maltodextrin) during 8 weeks of HVRT. Prior to and following HVRT and supplementation, assessments were made for muscle strength, muscle thickness, peak torque, and physical performance. There was a significant increase over time for all measures of muscle strength (p < 0.001), muscle thickness (p < 0.001), and some measures of peak torque (knee flexion; 1.05 and 3.14 rad/s; p < 0.001) and physical performance (balance board time-to-completion; p = 0.017). There was a group × time interaction for leg press strength (p = 0.044) and total lower-body strength (leg press, knee flexion, knee extension combined; p = 0.039). The creatine group experienced greater gains in leg press and total lower-body strength compared with the placebo group, with no other differences. HVRT increases muscle strength, muscle thickness, and some measures of peak torque and physical performance in untrained healthy aging males. The addition of creatine supplementation to HVRT further augments the gains in leg press and total lower-body strength.

Novelty High-velocity resistance training increases muscle mass and performance. Creatine supplementation increases lower-body muscle strength. High-velocity resistance training and creatine supplementation are safe interventions for aging adults.