Effect of different frequencies of creatine supplementation on muscle size and strength in young adults

The Effects of Creatine Supplementation Combined with Resistance Training on Regional Measures of Muscle Hypertrophy: A Systematic Review with Meta-Analysis

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.

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.

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.

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.

Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation

Sarcopenia, defined as the age-related decrease in muscle mass, strength and physical performance, is associated with reduced bone mass and elevated low-grade inflammation. From a healthy aging perspective, interventions which overcome sarcopenia are clinically relevant. Accumulating evidence suggests that exogenous creatine supplementation has the potential to increase aging muscle mass, muscle performance, and decrease the risk of falls and possibly attenuate inflammation and loss of bone mineral. Therefore, the purpose of this review is to: (1) summarize the effects of creatine supplementation, with and without resistance training, in aging adults and discuss possible mechanisms of action, (2) examine the effects of creatine on bone biology and risk of falls, (3) evaluate the potential anti-inflammatory effects of creatine and (4) determine the safety of creatine supplementation in aging adults.

Dietary Creatine Supplementation in Gilthead Seabream (Sparus aurata) Increases Dorsal Muscle Area and the Expression of myod1 and capn1 Genes

Creatine (Cr) is an amino acid derivative with an important role in the cell as energy buffer that has been largely used as dietary supplement to increase muscle strength and lean body mass in healthy individuals and athletes. However, studies in fish are scarce. The aim of this work is to determine whether dietary Cr supplementation affects muscle growth in gilthead seabream (Sparus aurata) juveniles. Fish were fed ad libitum for 69 days with diets containing three increasing levels of creatine monohydrate (2, 5, and 8%) that were compared with a non-supplemented control (CTRL) diet. At the end of the trial, the fast-twist skeletal muscle growth dynamics (muscle cellularity) and the expression of muscle-related genes were evaluated. There was a general trend for Cr-fed fish to be larger and longer than those fed the CTRL, but no significant differences in daily growth index (DGI) were registered among dietary treatments. The dorsal cross-sectional muscle area (DMA) of fish fed Cr 5 and Cr 8% was significantly larger than that of fish fed CTRL. The groups supplemented with Cr systematically had a higher relative number of both small-sized (≤20 μm) and large-sized fibers (≥120 μm). Dorsal total fibers number was highest in fish fed 5% Cr. In fish supplemented with 5% Cr, the relative expression of myogenic differentiation 1 (myod1) increased almost four times compared to those fed the CTRL diet. The relative expression of calpain 3 (capn3) was highest in fish fed diets with 2% Cr supplementation, but did not differ significantly from those fed the CTRL or Cr 5%. The myod1 gene expression had a positive and significant correlation with that of capn1, capns1a, and capn3 expression. These results suggest that the observed modulation of gene expression was not enough to produce a significant alteration in muscle phenotype under the tested conditions, as a non-significant increase in muscle fiber diameter and higher total number of fiber was observed, but still resulted in increased DMA. Additional studies may be required in order to better clarify the effect of dietary Cr supplementation in fish, possibly in conjunction with induced resistance training.

Nutrition and Supplementation in Soccer

Contemporary elite soccer features increased physical demands during match-play, as well as a larger number of matches per season. Now more than ever, aspects related to performance optimization are highly regarded by both players and soccer coaches. Here, nutrition takes a special role as most elite teams try to provide an adequate diet to guarantee maximum performance while ensuring a faster recovery from matches and training exertions. It is currently known that manipulation and periodization of macronutrients, as well as sound hydration practices, have the potential to interfere with training adaptation and recovery. A careful monitoring of micronutrient status is also relevant to prevent undue fatigue and immune impairment secondary to a deficiency status. Furthermore, the sensible use of evidence-based dietary supplements may also play a role in soccer performance optimization. In this sense, several nutritional recommendations have been issued. This detailed and comprehensive review addresses the most relevant and up-to-date nutritional recommendations for elite soccer players, covering from macro and micronutrients to hydration and selected supplements in different contexts (daily requirements, pre, peri and post training/match and competition).

Strategic creatine supplementation and resistance training in healthy older adults

Creatine supplementation in close proximity to resistance training may be an important strategy for increasing muscle mass and strength; however, it is unknown whether creatine supplementation before or after resistance training is more effective for aging adults. Using a double-blind, repeated measures design, older adults (50–71 years) were randomized to 1 of 3 groups: creatine before (CR-B: n = 15; creatine (0.1 g/kg) immediately before resistance training and placebo (0.1 g/kg cornstarch maltodextrin) immediately after resistance training), creatine after (CR-A: n = 12; placebo immediately before resistance training and creatine immediately after resistance training), or placebo (PLA: n = 12; placebo immediately before and immediately after resistance training) for 32 weeks. Prior to and following the study, body composition (lean tissue, fat mass; dual-energy X-ray absorptiometry) and muscle strength (1-repetition maximum leg press and chest press) were assessed. There was an increase over time for lean tissue mass and muscle strength and a decrease in fat mass (p < 0.05). CR-A resulted in greater improvements in lean tissue mass (Δ 3.0 ± 1.9 kg) compared with PLA (Δ 0.5 ± 2.1 kg; p < 0.025). Creatine supplementation, independent of the timing of ingestion, increased muscle strength more than placebo (leg press: CR-B, Δ 36.6 ± 26.6 kg; CR-A, Δ 40.8 ± 38.4 kg; PLA, Δ 5.6 ± 35.1 kg; chest press: CR-B, Δ 15.2 ± 13.0 kg; CR-A, Δ 15.7 ± 12.5 kg; PLA, Δ 1.9 ± 14.7 kg; p < 0.025). Compared with resistance training alone, creatine supplementation improves muscle strength, with greater gains in lean tissue mass resulting from post-exercise creatine supplementation.

PGC-1α and PGC-1β increase CrT expression and creatine uptake in myotubes via ERRα

Intramuscular creatine plays a crucial role in maintaining skeletal muscle energy homeostasis, and its entry into the cell is dependent upon the sodium chloride dependent Creatine Transporter (CrT; Slc6a8). CrT activity is regulated by a number of factors including extra- and intracellular creatine concentrations, hormones, changes in sodium concentration, and kinase activity, however very little is known about the regulation of CrT gene expression. The present study aimed to investigate how Creatine Transporter (CrT) gene expression is regulated in skeletal muscle. Within the first intron of the CrT gene, we identified a conserved sequence that includes the motif recognized by the Estrogen-related receptor α (ERRα), also known as an Estrogen-related receptor response element (ERRE). Additional ERREs confirming to the known consensus sequence were also identified in the region upstream of the promoter. When partnered with peroxisome proliferator-activated receptor-gamma co-activator-1alpha (PGC-1α) or beta (PGC-1β), ERRα induces the expression of many genes important for cellular bioenergetics. We therefore hypothesized that PGC-1 and ERRα could also regulate CrT gene expression and creatine uptake in skeletal muscle. Here we show that adenoviral overexpression of PGC-1α or PGC-1β in L6 myotubes increased CrT mRNA (2.1 and 1.7-fold, P<0.0125) and creatine uptake (1.8 and 1.6-fold, P<0.0125), and this effect was inhibited with co-expression of shRNA for ERRα. Overexpression of a constitutively active ERRα (VP16-ERRα) increased CrT mRNA approximately 8-fold (P<0.05), resulting in a 2.2-fold (P<0.05) increase in creatine uptake. Lastly, chromatin immunoprecipitation assays revealed that PGC-1α and ERRα directly interact with the CrT gene and increase CrT gene expression.

Ingestion of low-dose ibuprofen following resistance exercise in postmenopausal women

BACKGROUND

Postmenopausal women typically experience accelerated muscle loss which has a negative effect on strength. The maximum daily recommended dosage of ibuprofen (1,200 mg) following resistance exercise has been shown to increase muscle hypertrophy and strength in older adults. This study aimed to determine the effects of low-dose ibuprofen (400 mg) immediately following resistance exercise sessions on muscle mass and strength in postmenopausal women.

METHODS

Participants were randomized to ingest ibuprofen (IBU: n = 15, 57.8 ± 5.1 years, 75.9 ± 9.0 kg, 165.9 ± 6.2 cm, BMI = 28 ± 4 kg/m(2)) or placebo (PLA: n = 13, 56.5 ± 4.4 years, 73.0 ± 10.4 kg, 163.1 ± 5.9 cm, BMI = 26 ± 9 kg/m(2)) immediately following resistance exercise (11 whole-body exercises), which was performed 3 days/week, on nonconsecutive days, for 9 weeks. Prior to and following training, measures were taken for lean tissue mass (dual-energy X-ray absorptiometry), muscle size of the elbow and knee flexors and extensors and ankle dorsiflexors and plantar flexors (ultrasound), and strength (one-repetition maximum leg press and chest press).

RESULTS

Over the 9 weeks of training, there were significant changes (p < 0.05) in lean tissue mass (IBU, -1.1 ± 1.0 kg; PLA, -0.7 ± 1.4 kg), muscle size of the knee extensors (IBU, 0.3 ± 0.6 cm; PLA, 0.2 ± 0.7 cm), ankle dorsiflexors (IBU, 0.5 ± 0.8 cm; PLA, 0.1 ± 0.5 cm), and ankle plantar flexors (IBU, 0.3 ± 0.9 cm; PLA, 0.5 ± 0.9 cm), leg press strength (IBU, 20.6 ± 18.0 kg; PLA, 20.0 ± 20.0 kg), and chest press strength (IBU, 5.1 ± 9.5 kg; PLA, 8.1 ± 7.6 kg), with no differences between groups.

CONCLUSION

Low-dose ibuprofen following resistance exercise has no greater effect on muscle mass or strength over exercise alone in postmenopausal women.

Neuromuscular ultrasonography: quantifying muscle and nerve measurements

Neuromuscular ultrasonography can be used both descriptively and quantitatively in the evaluation of patients with neuromuscular disorders. This article reviews the quantitative use of this technology, particularly measurements of the size and echogenicity of nerve and muscle, as a tool for assessing the severity, progression, and response of these tissues to therapeutic interventions. Neuromuscular ultrasonography has several features, including portability and noninvasiveness, that make it an attractive research tool for advancing the diagnosis and treatment of neuromuscular disorders.