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BACKGROUND: Despite the robust evidence demonstrating positive effects from creatine supplementation (primarily when associated with resistance training) on measures of body composition, there is a lack of a comprehensive evaluation regarding the influence of creatine protocol parameters (including dose and form) on body mass and estimates of fat-free and fat mass. METHODS: Randomized controlled trials (RCTs) evaluating the effect of creatine supplementation on body composition were included. Electronic databases, including PubMed, Web of Science, and Scopus were searched up to July 2023. Heterogeneity tests were performed. Random effect models were assessed based on the heterogeneity tests, and pooled data were examined to determine the weighted mean difference (WMD) with a 95% confidence interval (CI). RESULTS: From 4831 initial records, a total of 143 studies met the inclusion criteria. Creatine supplementation increased body mass (WMD: 0.86 kg; 95% CI: 0.76 to 0.96, I2 = 0%) and fat-free mass (WMD: 0.82 kg; 95% CI: 0.57 to 1.06, I2 = 0%) while reducing body fat percentage (WMD: -0.28 %; 95% CI: -0.47 to -0.09; I2 = 0%). Studies that incorporated a maintenance dose of creatine or performed resistance training in conjunction with supplementation had greater effects on body composition. CONCLUSION: Creatine supplementation has a small effect on body mass and estimates of fat-free mass and body fat percentage. These findings were more robust when combined with resistance training.
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Composição Corporal , Creatina , Suplementos Nutricionais , Treinamento Resistido , Creatina/administração & dosagem , Creatina/farmacologia , Humanos , Composição Corporal/efeitos dos fármacos , Ensaios Clínicos Controlados Aleatórios como Assunto , Relação Dose-Resposta a DrogaRESUMO
Preliminary studies demonstrated beneficial effects of dietary creatine across different post-viral fatigue syndromes. Creatine is often co-administered with glucose to improve its potency yet whether glucose boost the efficacy of creatine in long COVID remains currently unknown. In this report, we investigate the effects of 8-wk creatine intake with and without glucose on patient-reported outcomes, exercise tolerance, and tissue creatine levels in patients with long COVID. Fifteen male and female long COVID adult patients (age 39.7±16.0 y; 9 women) with moderate fatigue and at least one of additional long COVID-related symptoms volunteered to participate in this randomized controlled parallel-group interventional trial. All patients were allocated in a double-blind parallel-group design (1 : 1 : 1) to receive creatine (8 g of creatine monohydrate per day), a mixture of creatine and glucose (8 g of creatine monohydrate and 3 g of glucose per day), or placebo (3 g of glucose per day) t.i.d. during an 8-wk intervention interval. Two-way ANOVA with repeated measures (treatment vs. time interaction) revealed significant differences in changes in total creatine levels between the groups, showing an interaction effect at two brain locations (right precentral white matter F=34.740, p=0.008; partial η2=0.72; left paracentral grey matter F=19.243, p=0.019; partial η2=0.88), with creatine and creatine-glucose outcompeted placebo to elevate creatine levels at these two locations. Several long COVID symptoms (including body aches, breathing problems, difficulties concentrating, headache, and general malaise) were significantly reduced in creatine-glucose group at 8-wk follow-up (p≤0.05); the effect sizes for reducing body aches, difficulties concentrating, and headache were 1.33, 0.80, and 1.12, respectively, suggesting a large effect of creatine-glucose mixture for these outcomes. Our preliminary findings suggest that supplying exogenous creatine with glucose could be recommended as an effective procedure in replenishing brain creatine pool and alleviating long COVID features in this prevalent condition.
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COVID-19 , Creatina , Suplementos Nutricionais , Glucose , Humanos , Creatina/administração & dosagem , Masculino , Feminino , Método Duplo-Cego , Adulto , Glucose/administração & dosagem , Pessoa de Meia-Idade , COVID-19/complicações , SARS-CoV-2 , Fadiga/tratamento farmacológico , Síndrome de COVID-19 Pós-Aguda , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Resultado do TratamentoRESUMO
Protein supplementation often refers to increasing the intake of this particular macronutrient through dietary supplements in the form of powders, ready-to-drink shakes, and bars. The primary purpose of protein supplementation is to augment dietary protein intake, aiding individuals in meeting their protein requirements, especially when it may be challenging to do so through regular food (i.e. chicken, beef, fish, pork, etc.) sources alone. A large body of evidence shows that protein has an important role in exercising and sedentary individuals. A PubMed search of "protein and exercise performance" reveals thousands of publications. Despite the considerable volume of evidence, it is somewhat surprising that several persistent questions and misconceptions about protein exist. The following are addressed: 1) Is protein harmful to your kidneys? 2) Does consuming "excess" protein increase fat mass? 3) Can dietary protein have a harmful effect on bone health? 4) Can vegans and vegetarians consume enough protein to support training adaptations? 5) Is cheese or peanut butter a good protein source? 6) Does consuming meat (i.e., animal protein) cause unfavorable health outcomes? 7) Do you need protein if you are not physically active? 8) Do you need to consume protein ≤ 1 hour following resistance training sessions to create an anabolic environment in skeletal muscle? 9) Do endurance athletes need additional protein? 10) Does one need protein supplements to meet the daily requirements of exercise-trained individuals? 11) Is there a limit to how much protein one can consume in a single meal? To address these questions, we have conducted a thorough scientific assessment of the literature concerning protein supplementation.
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Proteínas Alimentares , Resistência Física , Humanos , Resistência Física/fisiologia , Exercício Físico/fisiologia , Suplementos Nutricionais , Músculo Esquelético/fisiologiaRESUMO
Hemodialysis has a detrimental effect on fat-free mass (FFM) and muscle strength over time. Thus, we aimed to evaluate the effect of creatine supplementation on the body composition and Malnutrition-Inflammation Score (MIS) in patients with chronic kidney disease (CKD) undergoing hemodialysis. An exploratory 1-year balanced, placebo-controlled, and double-blind design was conducted with hemodialysis patients (≥18 years). The creatine group (CG) received 5 g of creatine monohydrate and 5 g of maltodextrin per day and the placebo group (PG) received 10 g of maltodextrin per day. MIS and body composition were analyzed at three time points: pre, intermediate (after 6 months), and post (after 12 months). After 6 months, 60% of patients on creatine experienced an increase in FFM compared to a 36.8% increase for those on placebo. Moreover, 65% of patients on creatine increased their skeletal muscle mass index (SMMI) compared to only 15.8% for those on placebo. Creatine increased intracellular water (ICW) in 60% of patients. MIS did not change after the intervention. In the CG, there was an increase in body weight (p = 0.018), FFM (p = 0.010), SMMI (p = 0.022). CG also increased total body water (pre 35.4 L, post 36.1 L; p = 0.008), mainly due to ICW (pre 20.2 L, intermediate 20.7 L, post 21.0 L; p = 0.016). Long-term creatine supplementation in hemodialysis patients did not attenuate the MIS, but enhanced FFM and SMMI, which was likely triggered by an increase in ICW.
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Creatina , Desnutrição , Humanos , Composição Corporal , Suplementos Nutricionais , Método Duplo-Cego , Inflamação/metabolismo , Desnutrição/metabolismo , Músculo Esquelético/metabolismo , Água/metabolismo , Adolescente , AdultoRESUMO
Caffeine is a popular ergogenic aid that has a plethora of evidence highlighting its positive effects. A Google Scholar search using the keywords "caffeine" and "exercise" yields over 200,000 results, emphasizing the extensive research on this topic. However, despite the vast amount of available data, it is intriguing that uncertainties persist regarding the effectiveness and safety of caffeine. These include but are not limited to: 1. Does caffeine dehydrate you at rest? 2. Does caffeine dehydrate you during exercise? 3. Does caffeine promote the loss of body fat? 4. Does habitual caffeine consumption influence the performance response to acute caffeine supplementation? 5. Does caffeine affect upper vs. lower body performance/strength differently? 6. Is there a relationship between caffeine and depression? 7. Can too much caffeine kill you? 8. Are there sex differences regarding caffeine's effects? 9. Does caffeine work for everyone? 10. Does caffeine cause heart problems? 11. Does caffeine promote the loss of bone mineral? 12. Should pregnant women avoid caffeine? 13. Is caffeine addictive? 14. Does waiting 1.5-2.0 hours after waking to consume caffeine help you avoid the afternoon "crash?" To answer these questions, we performed an evidence-based scientific evaluation of the literature regarding caffeine supplementation.
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Cafeína , Substâncias para Melhoria do Desempenho , Masculino , Gravidez , Humanos , Feminino , Cafeína/farmacologia , Tecido Adiposo , Exercício Físico , Substâncias para Melhoria do Desempenho/farmacologia , Suplementos NutricionaisRESUMO
Despite the abundance of research investigating the efficacy of caffeine supplementation on exercise performance, the physiological and biochemical responses to caffeine supplementation during intermittent activities are less evident. This study investigated the acute effects of caffeine supplementation on measures of exercise performance, ratings of perceived exertion, and biomarkers of oxidative stress induced by an acute bout of sprint interval training. In a randomized crossover design, 12 healthy males (age: 26 ± 4 years, height: 177.5 ± 6 cm, body mass: 80.7 ± 7.6 kg) ingested 6 mg/kg of caffeine or placebo 60 min prior to performing sprint interval training (12 × 6 s "all-out sprints" interspersed by 60 s of rest). Performance scores and ratings of perceived exertion were assessed after every sprint. Blood samples were collected before supplementation, prior to and following each sprint, and 5 and 60 min after the last sprint. Caffeine had no effect on any performance measures, ratings of perceived exertion, or biomarkers of oxidative stress (p > .05). In conclusion, caffeine supplementation does not improve performance or decrease oxidative stress after an acute bout of sprint interval training.
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Desempenho Atlético , Treinamento Intervalado de Alta Intensidade , Corrida , Adulto , Humanos , Masculino , Adulto Jovem , Desempenho Atlético/fisiologia , Biomarcadores , Cafeína/farmacologia , Estudos Cross-Over , Método Duplo-Cego , Estresse Oxidativo , Corrida/fisiologiaRESUMO
PURPOSE: Hemp contains protein with high concentrations of the branched-chain amino acids leucine, isoleucine, and valine and oils that have anti-inflammatory properties. Our purpose was to investigate the effects of hemp supplementation during resistance training in trained young adults. METHODS: Males (n = 22, 29 ± 8y) and females (n = 12, 30 ± 9y) were randomized (double-blind) to receive 60 g/d of hemp (containing 40 g protein and 9 g oil) or 60 g/d of soy (matched for protein and calories) during eight weeks of resistance training (~ 4x/week). Before and after the intervention, participants were assessed for whole-body lean tissue and fat mass (dual-energy X-ray absorptiometry), regional muscle hypertrophy (ultrasound), strength (1-repetition maximum leg press, bench press, biceps curl), voluntary activation (interpolated twitch technique), resting twitch properties (single pulse; 0.5 ms) (before and after a fatigue test), markers of inflammation (Interleukin 6 and C-reactive protein), and bone resorption (urinary N-telopeptides). RESULTS: Hemp supplementation increased elbow flexor muscle thickness in females (2.6 ± 0.4-3.1 ± 0.5 cm, p = 0.012) while soy supplementation increased elbow flexor muscle thickness in males (3.7 ± 0.4-4.0 ± 0.5 cm, p < 0.01). Twitch torque and rate of torque development were preserved after a fatigue test in males consuming hemp compared to males on soy (p < 0.001). CONCLUSION: Overall, hemp provides some sex-specific beneficial effects on measures of muscle accretion and torque under fatiguing conditions in resistance trained young adults. CLINICALTRIALS: gov Identifier: NCT02529917, registered August 11, 2015.
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Cannabis , Doenças Musculares , Treinamento Resistido , Feminino , Humanos , Masculino , Adulto Jovem , Composição Corporal , Suplementos Nutricionais , Método Duplo-Cego , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , AdultoRESUMO
This exploratory study aimed to investigate the long-term effects of multiple concussions on prefrontal cortex oxygenation during a five-minute hypercapnic challenge using Near Infrared Spectroscopy (NIRS). 55 physically active retired contact sport male athletes with three or more previous concussions (mTBI) were recruited along with 29 physically active males with no concussions history (CTRL). Participants completed five minutes of seated rest prior to the five-minute hypercapnic challenge (20-second breath-hold, 40-second recovery breathing; five times). NIRS measured right and left side oxygenated (O2Hb), deoxygenated (HHb), total (tHb) haemoglobin, and haemoglobin difference (HbDiff) with all parameters analysed through changes in average maximal and minimal values (ΔMAX), Z-scores, and standard deviations. Right prefrontal cortex HbDiff ΔMAX was significantly higher in the mTBI compared to CTRL (p = 0.045) group. Left prefrontal cortex O2Hb ΔMAX (p = 0.040), HHb Z-Scores (p = 0.008), and HbDiff ΔMAX(p = 0.014) were significantly higher in the mTBI group. Within-group right vs left analyses demonstrated significantly lower left HbDiff ΔMAX (p = 0.048) and HbDiff Z-scores (p = 0.002) in the mTBI group, while the CTRL group had significantly lower left HHb Z-scores (p = 0.003) and left tHb Z-scores (p = 0.042). This study provides preliminary evidence that athletes with a history of three or more concussions may have impaired prefrontal cortex oxygenation parameters during a hypercapnic challenge.
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Concussão Encefálica , Oxiemoglobinas , Humanos , Masculino , Oxiemoglobinas/metabolismo , Hemoglobinas/metabolismo , Córtex Pré-Frontal/metabolismo , AtletasRESUMO
The combination of resistance exercise and creatine supplementation has been shown to decrease body fat percentage in adults ≥ 50 years of age. However, the effect on adults < 50 years of age is currently unknown. To address this limitation, we systematically reviewed the literature and performed several meta-analyses comparing studies that included resistance exercise and creatine supplementation to resistance exercise and placebo on fat mass and body fat percentage Twelve studies were included, involving 266 participants. Adults (<50 years of age) who supplemented with creatine and performed resistance exercise experienced a very small, yet significant reduction in body fat percentage (-1.19%, p = 0.006); however, no difference was found in absolute fat mass (-0.18 kg, p = 0.76). Collectively, in adults < 50 years of age, the combination of resistance exercise and creatine supplementation produces a very small reduction in body fat percentage without a corresponding decrease in absolute fat mass.
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Creatina , Treinamento Resistido , Humanos , Adulto , Exercício Físico , Suplementos Nutricionais , Composição Corporal , Músculo Esquelético , Força MuscularRESUMO
To determine if creatine (Cr) supplementation could influence cognitive performance and whether any changes were related to changes in prefrontal cortex (PFC) activation during such cognitive tasks, thirty (M = 11, F = 19) participants were evenly randomized to receive supplementation with Cr (CR10:10 g/day or CR20:20 g/day) or a placebo (PLA:10 g/day) for 6 weeks. Participants completed a cognitive test battery (processing speed, episodic memory, and attention) on two separate occasions prior to and following supplementation. Functional near-infrared spectroscopy (fNIRS) was used to measure PFC oxyhemoglobin (O2Hb) during the cognitive evaluation. A two-way repeated measures ANOVA was used to determine the differences between the groups and the timepoints for the cognitive performance scores and PFC O2Hb. In addition, a one-way ANOVA of % change was used to determine pre- and post-differences between the groups. Creatine (independent of dosage) had no significant effect on the measures of cognitive performance. There was a trend for decreased relative PFC O2Hb in the CR10 group versus the PLA group in the processing speed test (p = 0.06). Overall, six weeks of Cr supplementation at a moderate or high dose does not improve cognitive performance or change PFC activation in young adults.
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AIMS: Sarcopenia generally refers to the age-related reduction in muscle strength, functional ability, and muscle mass. Sarcopenia is a multifactorial condition associated with poor glucose disposal, insulin resistance, and subsequently type 2 diabetes (T2D). The pathophysiological connection between sarcopenia and T2D is complex but likely involves glycemic control, inflammation, oxidative stress, and adiposity. METHODS AND RESULTS: Resistance exercise and aerobic training are two lifestyle interventions that may improve glycemic control in older adults with T2D and counteract sarcopenia. Further, there is evidence that dietary protein, Omega-3 fatty acids, creatine monohydrate, and Vitamin D hold potential to augment some of these benefits from exercise. CONCLUSIONS: The purpose of this narrative review is: (1) discuss the pathophysiological link between age-related sarcopenia and T2D, and (2) discuss lifestyle interventions involving physical activity and nutrition that may counteract sarcopenia and T2D.
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PURPOSE OF REVIEW: The purpose of this opinion paper is to provide current-day and evidence-based information regarding dietary supplements that support resistance training adaptations or acutely enhance strength-power or endurance performance. RECENT FINDINGS: Several independent lines of evidence support that higher protein diets, which can be readily achieved through animal-based protein supplements, optimize muscle mass during periods of resistance training, and this likely facilitates strength increases. Creatine monohydrate supplementation and peri-exercise caffeine consumption also enhance strength and power through distinct mechanisms. Supplements that favorably affect aspects of endurance performance include peri-exercise caffeine, nitrate-containing supplements (e.g., beet root juice), and sodium bicarbonate consumption. Further, beta-alanine supplementation can enhance high-intensity endurance exercise efforts. SUMMARY: Select dietary supplements can enhance strength and endurance outcomes, and take-home recommendations will be provided for athletes and practitioners aiming to adopt these strategies.
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The purpose of this paper was to carry out a systematic review with a meta-analysis of randomized controlled trials that examined the combined effects of resistance training (RT) and creatine supplementation on regional changes in muscle mass, with direct imaging measures of hypertrophy. Moreover, we performed regression analyses to determine the potential influence of covariates. We included trials that had a duration of at least 6 weeks and examined the combined effects of creatine supplementation and RT on site-specific direct measures of hypertrophy (magnetic resonance imaging (MRI), computed tomography (CT), or ultrasound) in healthy adults. A total of 44 outcomes were analyzed across 10 studies that met the inclusion criteria. A univariate analysis of all the standardized outcomes showed a pooled mean estimate of 0.11 (95% Credible Interval (CrI): -0.02 to 0.25), providing evidence for a very small effect favoring creatine supplementation when combined with RT compared to RT and a placebo. Multivariate analyses found similar small benefits for the combination of creatine supplementation and RT on changes in the upper and lower body muscle thickness (0.10-0.16 cm). Analyses of the moderating effects indicated a small superior benefit for creatine supplementation in younger compared to older adults (0.17 (95%CrI: -0.09 to 0.45)). In conclusion, the results suggest that creatine supplementation combined with RT promotes a small increase in the direct measures of skeletal muscle hypertrophy in both the upper and lower body.
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Creatina , Treinamento Resistido , Humanos , Idoso , Hipertrofia , Músculos , Suplementos NutricionaisRESUMO
There is emerging interest regarding the potential beneficial effects of creatine supplementation on indices of brain health and function. Creatine supplementation can increase brain creatine stores, which may help explain some of the positive effects on measures of cognition and memory, especially in aging adults or during times of metabolic stress (i.e., sleep deprivation). Furthermore, creatine has shown promise for improving health outcome measures associated with muscular dystrophy, traumatic brain injury (including concussions in children), depression, and anxiety. However, whether any sex- or age-related differences exist in regard to creatine and indices of brain health and function is relatively unknown. The purpose of this narrative review is to: (1) provide an up-to-date summary and discussion of the current body of research focusing on creatine and indices of brain health and function and (2) discuss possible sex- and age-related differences in response to creatine supplementation on brain bioenergetics, measures of brain health and function, and neurological diseases.
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Encéfalo , Creatina , Adulto , Criança , Humanos , Creatina/farmacologia , Encéfalo/metabolismo , Cognição , Envelhecimento , Suplementos NutricionaisRESUMO
PURPOSE: Our purpose was to examine the effects of 2 yr of creatine monohydrate supplementation and exercise on bone health in postmenopausal women. METHODS: Two hundred and thirty-seven postmenopausal women (mean age, 59 yr) were randomized to receive creatine (0.14 g·kg -1 ·d -1 ) or placebo during a resistance training (3 d·wk -1 ) and walking (6 d·wk -1 ) program for 2 yr. Our primary outcome was the femoral neck bone mineral density (BMD), with lumbar spine BMD and proximal femur geometric properties as the secondary outcomes. RESULTS: Compared with placebo, creatine supplementation had no effect on BMD of the femoral neck (creatine: 0.725 ± 0.110 to 0.712 ± 0.100 g·cm -2 ; placebo: 0.721 ± 0.102 to 0.706 ± 0.097 g·cm -2 ), total hip (creatine: 0.879 ± 0.118 to 0.872 ± 0.114 g·cm -2 ; placebo: 0.881 ± 0.111 to 0.873 ± 0.109 g·cm -2 ), or lumbar spine (creatine: 0.932 ± 0.133 to 0.925 ± 0.131 g·cm -2 ; placebo: 0.923 ± 0.145 to 0.915 ± 0.143 g·cm -2 ). Creatine significantly maintained section modulus (1.35 ± 0.29 to 1.34 ± 0.26 vs 1.34 ± 0.25 to 1.28 ± 0.23 cm 3 (placebo), P = 0.0011), predictive of bone bending strength, and buckling ratio (10.8 ± 2.6 to 11.1 ± 2.2 vs 11.0 ± 2.6 to 11.6 ± 2.7 (placebo), P = 0.011), predictive of reduced cortical bending under compressive loads, at the narrow part of the femoral neck. Creatine reduced walking time over 80 m (48.6 ± 5.6 to 47.1 ± 5.4 vs 48.3 ± 4.5 to 48.2 ± 4.9 s (placebo), P = 0.0008) but had no effect on muscular strength (i.e., one-repetition maximum) during bench press (32.1 ± 12.7 to 42.6 ± 14.1 vs 30.6 ± 10.9 to 41.4 ± 14 kg (placebo)) and hack squat (57.6 ± 21.6 to 84.4 ± 28.1 vs 56.6 ± 24.0 to 82.7 ± 25.0 kg (placebo)). In the subanalysis of valid completers, creatine increased lean tissue mass compared with placebo (40.8 ± 5.7 to 43.1 ± 5.9 vs 40.4 ± 5.3 to 42.0 ± 5.2 kg (placebo), P = 0.046). CONCLUSIONS: Two years of creatine supplementation and exercise in postmenopausal women had no effect on BMD; yet, it improved some bone geometric properties at the proximal femur.
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Densidade Óssea , Osteoporose Pós-Menopausa , Feminino , Humanos , Pessoa de Meia-Idade , Creatina , Pós-Menopausa , Osteoporose Pós-Menopausa/complicações , Osteoporose Pós-Menopausa/tratamento farmacológico , Colo do Fêmur , Suplementos Nutricionais , Método Duplo-CegoRESUMO
Creatine supplementation is an effective ergogenic aid to augment resistance training and improve intense, short duration, intermittent performance. The effects on endurance performance are less known. The purpose of this brief narrative review is to discuss the potential mechanisms of how creatine can affect endurance performance, defined as large muscle mass activities that are cyclical in nature and are >~3 min in duration, and to highlight specific nuances within the literature. Mechanistically, creatine supplementation elevates skeletal muscle phosphocreatine (PCr) stores facilitating a greater capacity to rapidly resynthesize ATP and buffer hydrogen ion accumulation. When co-ingested with carbohydrates, creatine enhances glycogen resynthesis and content, an important fuel to support high-intensity aerobic exercise. In addition, creatine lowers inflammation and oxidative stress and has the potential to increase mitochondrial biogenesis. In contrast, creatine supplementation increases body mass, which may offset the potential positive effects, particularly in weight-bearing activities. Overall, creatine supplementation increases time to exhaustion during high-intensity endurance activities, likely due to increasing anaerobic work capacity. In terms of time trial performances, results are mixed; however, creatine supplementation appears to be more effective at improving performances that require multiple surges in intensity and/or during end spurts, which are often key race-defining moments. Given creatines ability to enhance anaerobic work capacity and performance through repeated surges in intensity, creatine supplementation may be beneficial for sports, such as cross-country skiing, mountain biking, cycling, triathlon, and for short-duration events where end-spurts are critical for performance, such as rowing, kayaking, and track cycling.
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Creatina , Resistência Física , Humanos , Resistência Física/fisiologia , Suplementos Nutricionais , Fosfocreatina , Músculo Esquelético , GlicogênioRESUMO
Collegiate dance is unique because it requires athletic and academic performance; therefore, optimizing physical and mental function is crucial. Research among athletic populations demonstrate improvements in body composition, performance, and cognition following creatine monohydrate (CR) supplementation, yet dancers have not been investigated. The purpose of this study was to determine the effects of CR supplementation on body composition, performance, and cognitive function in female collegiate dancers. Participants were randomized to CR (CR; n = 7; 0.1 g·kg -1·day -1 CM +0.1 g·kg -1·day -1 corn-starch maltodextrin) or placebo (PL; n = 6; 0.2 g·kg -1·day -1 corn-starch maltodextrin) for 42 days. Pre- and post-testing included body composition, total body water (TBW), Depression, Anxiety and Stress Scale, Diet History Questionnaire, the National Institute of Health Toolbox fluid cognition battery and isokinetic strength, vertical jump, medicine ball throw, and Wingate anaerobic power test. CR demonstrated a significant increase in TBW (pre, 32.2 ± 3.5 kg; post, 32.7 ± 3.6 kg; p = 0.024) and lean mass (LM; pre, 39.8 ± 3.6 kg; post, 41.5 ± 4.5 kg; p = 0.020). CR supplementation may be an effective strategy to increase TBW and estimates of LM in female collegiate dancers. Although this may optimize aesthetics, larger samples sizes with resistance training are needed to determine if CR supplementation increases muscle mass and translates to improved performance.
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Creatina , Força Muscular , Humanos , Feminino , Suplementos Nutricionais , Água Corporal , Composição Corporal , Músculo Esquelético , Método Duplo-CegoRESUMO
Habitual declines in sleep duration and increased rates of obesity are public health concerns worldwide. Accumulating evidence suggests a prominent link between reduced sleep duration and weight gain. Our cross-sectional study investigated the relationship between sleep duration and body fat distribution in US adults. We extracted data for 5151 participants (2575 men and 2576 women) aged 18-59 years from the US National Health and Nutrition Examination Survey 2011-2012 and 2013-2014. Weekday or workday night-time sleep duration was estimated using an in-home interview questionnaire. Dual-energy x-ray absorptiometry scans were used to determine regional body fat mass (arms, legs, trunk [android and gynoid], and abdominal [subcutaneous and visceral]). Multiple linear regression and restricted cubic spline analyses were performed after adjusting for several demographic, anthropometric, and nutritional covariates. There was a significant negative association between sleep duration and visceral fat mass overall (ß: -12.139, P < 0.001) and by sex (men: ß: -10.096, P < 0.001; women: ß: -11.545, P = 0.038), after adjusting for age, ethnicity, body mass index, total body fat mass, daily energy and alcohol intake, sleep quality and sleep disorder status. Sleep duration and visceral fat appeared to plateau at ≥ 8 h of daily sleep. Sleep duration is negatively associated with visceral fat mass accumulation during adulthood with possibly no benefits beyond 8 h of sleep per day. Mechanistic and prospective studies are required to confirm the effect of sleep duration on visceral adiposity and determine its causes.