Creatine Group Research Articles

Effect of creatine supplementation as a potential adjuvant therapy to exercise training in cardiac patients: a randomized controlled trial

Objective: To investigate the effect of oral creatine supplementation in conjunction with an exercise programme on physical fitness in patients with coronary artery disease or chronic heart failure. Design: Single centre double-blind randomized placebo controlled trial. Setting: Cardiac rehabilitation centre. Subjects and intervention: 70 (4 women) cardiac patients (age 57.5 (8.4) years) were randomized to a placebo (n = 37) or creatine (n = 33) treatment for three months. Combined aerobic endurance and resistance training (three sessions/ week) was performed during supplementation. Main Measures: Aerobic power was determined during graded bicycle testing, knee extensor peak isometric and isokinetic strength, endurance and recovery were assessed by an isokinetic dynamometer, and health related quality of life was evaluated with the SF-36 and MacNew Heart Disease questionnaires. In addition, blood samples were taken after an overnight fast and 24 hour urinary collection was performed. Results: At baseline there were no significant differences between both groups. We observed main time effects for aerobic power, muscle performance, health related quality of life, high density lipoprotein cholesterol and triglycerides (pre vs post; P<0.05 for all). However, changes after training were similar between placebo group and creatine group (P>0.05). Further, no detrimental effect on renal or liver function was observed nor were there any reports of side effects. Conclusion: Oral creatine supplementation in combination with exercise training does not exert any additional effect on the improvement in physical performance, health related quality of life, lipid profile in patients with coronary artery disease or chronic heart failure than exercise training alone.

Efeitos da suplementação prolongada de creatina mono-hidratada sobre o desempenho anaeróbio de adultos jovens treinados

O objetivo do presente estudo foi investigar o impacto de oito semanas de suplementação de creatina mono-hidratada (Crm) sobre o desempenho anaeróbio de adultos jovens treinados. Vinte e seis estudantes de educação física, do sexo masculino, saudáveis, foram divididos aleatoriamente em grupo creatina (GCr, n = 13; 22,5 ± 2,7 anos; 74,9 ± 6,8kg, 178,5 ± 4,8cm) e grupo placebo (GPl, n = 13; 22,9 ± 3,2 anos, 71,9 ± 11,3kg, 178,6 ± 4,0cm). Os indivíduos ingeriram em sistema duplo-cego doses de Crm ou placebo-maltodextrina (20 g.d-1 por 5 dias e 3 g.d-1 por 51 dias subsequentes). Ambos os grupos tiveram seus hábitos alimentares e os níveis de aptidão física controlados anteriormente. O teste anaeróbio de Wingate (TW) foi usado para avaliar o desempenho anaeróbio antes e após o período de ingestão de Crm ou placebo. Os índices de desempenho analisados foram: potência pico relativa (PPR), potência média relativa (PMR), trabalho total relativo (TTR) e índice de fadiga (IF). Para tratamento estatístico foi utilizado ANOVA, seguido pelo teste de post hoc Tukey, quando P&lt;0,05. Não foram observadas diferenças significantes nos índices PPR, PMR, TTR e IF após o período de suplementação de Crm (P&lt;0,05). Os resultados do presente estudo sugerem que a suplementação de Crm não parece ser um recurso ergogênico eficiente em esforços físicos de alta intensidade e curta duração que envolve uma única série.

Low Dose Creatine Supplementation Enhances Fatigue Resistance in the Absence of Weight Gain

Many studies have demonstrated the beneficial effects of high dose/short term creatine supplementation on muscle function. However, the effects of low dose/longer term creatine supplementation on muscle function are not well established, and the minimal effective dose is not known. PURPOSE: To examine the effects of 6 weeks of low dose creatine supplementation on body composition, muscle function, and body creatine retention. METHODS: Twenty healthy, non-vegetarian men and women (21 ± 2 yrs) were randomized to receive creatine (0.03g/kg/d) (n = 10; 4 F) or placebo (n = 10; 4 F) for six weeks in a double-blind placebo controlled fashion. Participants were tested on two occasions pre-supplementation to establish a reliable baseline, and then were retested post-supplementation. Testing included: body composition (BC-418 8-contact electrode bio-impedance analyzer), maximal strength (3-RM concentric knee extension at 180°/sec), muscle fatigue (5 × 30 concentric knee extensions at 180°/sec (Biodex Medical Systems)), and plasma creatine concentration. RESULTS: There were no significant differences in body mass, fat free mass, fat mass, body fat %, total body water, or maximal strength in either group from pre- to post-supplementation (all p > 0.05). Following supplementation, plasma creatine increased significantly in the creatine group (+182%, p = 0.03), with no difference in the placebo group. There was a significant effect of sets (p < 0.001) and a significant group by set interaction (p = 0.03) in the analysis of knee extensor fatigue indicating that muscle fatigue increased across sets and that fatigue was different between groups. Post-hoc analyses indicated that, relative to baseline values, creatine supplemented volunteers were more resistant to fatigue during sets two (7%), three (9%), four (9%), and five (11%) (all p < 0.05). CONCLUSIONS: Ingesting a low dose (2.3g/d) of creatine for 6 weeks significantly increased plasma creatine concentration and enhanced resistance to fatigue during repeated bouts of high-intensity contractions.

Strategic Creatine Supplementation and Resistance Training in Older Adults

Darren Candow, Tim Bolton, Katherine Mcleod, Jessica Lewis, James Lazorko, Nathan Hass. The timing of creatine supplementation is crucial for creating an anabolic environment for muscle growth. Recent evidence suggests that creatine ingestion before and after resistance training (RT) sessions may be more beneficial than ingesting creatine at other times of the day. However, it is unknown whether there is an advantage in supplementing creatine immediately before compared to immediately after RT in older adults. PURPOSE: To determine the effects of the timing of creatine supplementation and RT in older adults. METHODS: Healthy older adults were randomized to one of three groups: CR-Before (0.1g/kg-1 creatine before + placebo (rice flour) after RT, N=11, 56yrs), CR-After (placebo before + creatine after RT, N=11, 55yrs), and PLA (placebo before and after RT, N=11, 60yrs). RT (9 whole-body exercises) was performed 3x/week for 12 weeks. Prior to and following the study, measures were made for body composition (air-displacement plethysmography), muscle hypertrophy (ultrasound), and strength (1-repetition maximum leg press and chest press). RESULTS: Muscle mass and strength increased in all groups with training (p<0.05). There was a greater change in lean tissue mass in the Cr-After group compared to PLA (CR-After: 53.9±11→56.1±11.6kg, 4%; CR-Before: 50.6±14→52.1±15kg, 2.9%; PLA: 51.7±9→52.1±8kg, 0.8%; p<0.05). Both creatine groups experienced a greater increase in strength compared to PLA (leg press: Cr-After: 142±56→188±66kg, 32%; CR-Before: 134±52→187±75kg, 40%; PLA: 165±55→192±41kg, 16%; chest press: Cr-After: 52±33→74±31kg, 42%; CR-Before: 43±26→67±28kg, 56%; PLA: 65±28→74±30kg, 14%; p<0.05). The CR-After group had a greater increase in elbow flexor muscle hypertrophy compared to the Cr-Before and PLA groups (Cr-After: 3.7±0.8→4.4±1.0cm, 19%, CR-Before: 3.7±0.4→4.0±0.6cm, 8%, PLA: 3.0±0.4→3.1±0.5cm, 3%; p<0.05), with no other differences. CONCLUSIONS: Creatine supplementation and resistance training has a positive effect on muscle mass and strength. Supplementing with creatine immediately following exercise is an important factor for stimulating muscle accretion in healthy older adults. Supported by RIVALUS

Effect of 28 days of creatine ingestion on muscle metabolism and performance of a simulated cycling road race

PurposeThe effects of creatine supplementation on muscle metabolism and exercise performance during a simulated endurance road race was investigated.MethodsTwelve adult male (27.3 ± 1.0 yr, 178.6 ± 1.4 cm, 78.0 ± 2.5 kg, 8.9 ± 1.1 %fat) endurance-trained (53.3 ± 2.0 ml* kg-1* min-1, cycling ~160 km/wk) cyclists completed a simulated road race on a cycle ergometer (Lode), consisting of a two-hour cycling bout at 60% of peak aerobic capacity (VO2peak) with three 10-second sprints performed at 110% VO2 peak every 15 minutes. Cyclists completed the 2-hr cycling bout before and after dietary creatine monohydrate or placebo supplementation (3 g/day for 28 days). Muscle biopsies were taken at rest and five minutes before the end of the two-hour ride.ResultsThere was a 24.5 ± 10.0% increase in resting muscle total creatine and 38.4 ± 23.9% increase in muscle creatine phosphate in the creatine group (P < 0.05). Plasma glucose, blood lactate, and respiratory exchange ratio during the 2-hour ride, as well as VO2 peak, were not affected by creatine supplementation. Submaximal oxygen consumption near the end of the two-hour ride was decreased by approximately 10% by creatine supplementation (P < 0.05). Changes in plasma volume from pre- to post-supplementation were significantly greater in the creatine group (+14.0 ± 6.3%) than the placebo group (-10.4 ± 4.4%; P < 0.05) at 90 minutes of exercise. The time of the final sprint to exhaustion at the end of the 2-hour cycling bout was not affected by creatine supplementation (creatine pre, 64.4 ± 13.5s; creatine post, 88.8 ± 24.6s; placebo pre, 69.0 ± 24.8s; placebo post 92.8 ± 31.2s: creatine vs. placebo not significant). Power output for the final sprint was increased by ~33% in both groups (creatine vs. placebo not significant).ConclusionsIt can be concluded that although creatine supplementation may increase resting muscle total creatine, muscle creatine phosphate, and plasma volume, and may lead to a reduction in oxygen consumption during submaximal exercise, creatine supplementation does not improve sprint performance at the end of endurance cycling exercise.

The Effects Of Four Weeks Of High-Intensity Interval Training And Creatine Supplementation On Cardiorespiratory Fitness In College-Aged Men

The purpose of this study was to determine the effects of four weeks of interval training with concurrent creatine supplementation on cardiorespiratory fitness and endurance performance (maximal oxygen consumption (o2PEAK), time-to-exhaustion (o2PEAKTTE), ventilatory threshold (VT), and total work done (TWD)) in college-aged men. Forty-three recreationally active college-aged men (Age: 23.5 ± 4.8 yrs; o2PEAK: 43.9 ± 9.9 ml·kg·min−1) volunteered to participate in this double-blind, placebo-controlled study. Participants were randomly assigned to one of three groups: creatine (Cr-5g Cr plus 15g flavored dextrose; n = 16), placebo (PL-20g flavored dextrose; n = 17), or control (n = 10) groups. Each supplement group ingested the assigned supplement twice daily on training days only (10g/day, 5 days/week). Prior to and following supplementation, each participant performed a continuous maximal oxygen consumption test (o2PEAK) on a cycle ergometer (Corival Lode, Gronigen, the Netherlands), which was further used to establish o2PEAKTTE (seconds) and VT (l·min−1). Participants were further assessed for TWD (kJ), calculated from the total time (T; seconds) completed at a workload corresponding to 110% of their maximal power output (watt, W) determined from the maximal oxygen consumption test [TWD (kJ)= (T × W)/1000]. Following initial testing, a two week familiarization period of training and supplementing occurred. Baseline values were then measured and all participants in the Cr and PL groups engaged in four weeks of high-intensity interval training (HIIT) training on a cycle ergometer. Each training session consisted of 5 bouts of a 2:1 minute cycling work to rest ratio, introduced in an undulating progression starting at 80% o2PEAK power output and reaching 120%. Separate two-way ANOVAs (group [Cr vs. PL vs. CON] × time [Baseline- vs. Post-]) were used to identify any group by time interactions. A significant time × treatment interaction occurred for o2PEAK (p < 0.001) and o2PEAKTTE (p < 0.001). Post hoc analyses indicated no significant differences between groups. Both groups increased in o2PEAK (Cr: 7.5%; Pl: 9.6%) and o2PEAKTTE (Cr: 6.2%; PL: 7.4%) following four weeks of HIIT. A significant time × treatment interaction occurred for VT (p = 0.040). Post hoc analyses indicated improvements in only the Cr (p = 0.001; 16.4% increase) group over time. No changes were observed in TWD in any group over time. Both o2PEAK and o2PEAKTTE improved following four weeks of HIIT. Cr supplementation seemed to only have an effect on VT, since improvements were observed in the Cr group while there were no changes in the PL group. TWD did not change following HIIT or Cr supplementation. HIIT seems to be an effective and time-efficient way to improve maximal endurance performance. The addition of Cr seemed to improve VT, but did not increase TWD. Therefore, 10g of Cr per day for 5 days per week does not seem to further augment maximal oxygen consumption, greater than HIIT alone; however, Cr supplementation may improve submaximal exercise performance.

The Effects of Creatine Monohydrate Supplementation With and Without D-Pinitol on Resistance Training Adaptations

Coingestion of D-pinitol with creatine (CR) has been reported to enhance creatine uptake. The purpose of this study was to evaluate whether adding D-pinitol to CR affects training adaptations, body composition, whole-body creatine retention, and/or blood safety markers when compared to CR ingestion alone after 4 weeks of resistance training. Twenty-four resistance trained males were randomly assigned in a double-blind manner to creatine + pinitol (CRP) or creatine monohydrate (CR) prior to beginning a supervised 4-week resistance training program. Subjects ingested a typical loading phase (i.e., 20 g/d-1 for 5 days) before ingesting 5 g/d-1 the remaining 23 days. Performance measures were assessed at baseline (T0), week 1 (T1), and week 4 (T2) and included 1 repetition maximum (1RM) bench press (BP), 1RM leg press (LP), isokinetic knee extension, and a 30-second Wingate anaerobic capacity test. Fasting blood and body composition using dual-energy x-ray absorptiometry (DEXA) were determined at T1 and T3. Data were analyzed by repeated measures analysis of variance (ANOVA). Creatine retention increased (p < 0.001) in both groups as a result of supplementation but was not different between groups (p > 0.05). Significant improvements in upper- and lower-body strength and body composition occurred in both groups. However, significantly greater increases in lean mass and fat-free mass occurred in the CR group when compared to CRP (p <0.05). Adding D-pinitol to creatine monohydrate does not appear to facilitate further physiological adaptations while resistance training. Creatine monohydrate supplementation helps to improve strength and body composition while resistance training. Data from this study assist in determining the potential role the addition of D-pinitol to creatine may aid in facilitating training adaptations to exercise.

Effects of creatine supplementation on homocysteine levels and lipid peroxidation in rats

Hyperhomocysteinaemia is an independent risk factor for CVD. Recent data show a relationship between homocysteine (Hcy) and free radical formation. Since creatine synthesis is responsible for most of the methyl group transfers that result in Hcy formation, creatine supplementation might inhibit Hcy production and reduce free radical formation. The present study investigated the effects of creatine supplementation on Hcy levels and lipid peroxidation biomarkers. Thirty rats were divided into three groups: control group; diet with creatine group (DCr; 2 % creatine in the diet for 28 d); creatine overload plus diet with creatine group (CrO + D; 5 g creatine/kg by oral administration for 5 d+2 % in the diet for 23 d). Plasma Hcy was significantly lower (P < 0.05) in DCr (7.5 (sd 1.2) micromol/l) and CrO + D (7.2 (sd 1.7) micromol/l) groups compared with the control group (12.4 (sd 2.2) micromol/l). Both plasma thiobarbituric acid-reactive species (TBARS) (control, 10 (sd 3.4); DCr, 4.9 (sd 0.7); CrO + D, 2.4 (sd 1) micromol/l) and plasma total glutathione (control, 4.3 (sd 1.9); DCr, 2.5 (sd 0.8); CrO + D, 1.8 (sd 0.5) micromol/l) were lower in the groups that received creatine (P < 0.05). In addition, Hcy showed significant negative correlation (P < 0.05) with plasma creatine (r - 0.61) and positive correlation with plasma TBARS (r 0.74). Plasma creatine was negatively correlated with plasma TBARS (r - 0.75) and total peroxide (r - 0.40). We conclude that creatine supplementation reduces plasma Hcy levels and lipid peroxidation biomarkers, suggesting a protective role against oxidative damage. Modulating Hcy formation may, however, influence glutathione synthesis and thereby affect the redox state of the cells.

Oral creatine supplementation decreases plasma markers of adenine nucleotide degradation during a 1-h cycle test

We investigated the effect of oral creatine supplementation (20 g d(-1) for 7 days) on metabolism during a 1-h cycling performance trial. Twenty endurance-trained cyclists participated in this double-blind placebo controlled study. Five days after familiarization with the exercise test, the subjects underwent a baseline muscle biopsy. Thereafter, a cannula was inserted into a forearm vein before performing the baseline maximal 1-h cycle (test 1 (T1)). Blood samples were drawn at regular intervals during exercise and recovery. After creatine (Cr) loading, the muscle biopsy, 1-h cycling test (test 2 (T2)) and blood sampling were repeated. Resting muscle total creatine (TCr), measured by high performance liquid chromatography, was increased (P < 0.001) in the creatine group from 123.0 +/- 3.8 - 159.8 +/- 7.9 mmol kg(-1) dry wt, but was unchanged in the placebo group (126.7 +/- 4.7 - 127.5 +/- 3.6 mmol kg(-1) dry wt). The extent of Cr loading was unrelated to baseline Cr levels (r=0.33, not significant). Supplementation did not significantly improve exercise performance (Cr group: 39.1 +/- 0.9 vs. 39.8 +/- 0.8 km and placebo group: 39.3 +/- 0.8 vs. 39.2 +/- 1.1 km) or change plasma lactate concentrations. Plasma concentrations of ammonia (NH(3)) (P < 0.05) and hypoxanthine (Hx) (P < 0.01) were lower in the Cr group from T1 to T2. Our results indicate that Cr supplementation alters the metabolic response during sustained high-intensity submaximal exercise. Plasma data suggest that nett intramuscular adenine nucleotide degradation may be decreased in the presence of enhanced intramuscular TCr concentration even during submaximal exercise.

The Effects of Creatine and Protein Supplementation on Bone Catabolism in Older Men

Recent evidence suggests that creatine supplementation may have beneficial effects on bone. PURPOSE: To determine the effect of low-dose creatine combined with protein supplementation during resistance training on a marker of bone catabolism (N-telopeptide cross-links of type I collagen) in healthy older men. METHODS: Men (65.4±4.7y) were randomized (double blind) to receive either 0.1 g/ kg body mass/d creatine (n=13), 0.1 g/kg body mass/d creatine and 0.3 g/kg body mass/d protein (n=7), or protein only (n=11) for 10 weeks. Subjects ingested their supplements 3 days per week, with half of the supplement ingested before, and half ingested after performing a bout of whole-body resistance training. Twentyfour hour urine samples were collected before and after the 10 weeks of training and supplementation and analyzed by ELISA for N-telopeptide cross links of type I collagen (NTx). RESULTS: There were no signficant group x time interactions for absolute changes (changes from pre to post were: Creatine group 59±25 to 45±25; Creatine + Protein group 56±26 to 35±24; Protein group 51±27 to 47±23 nM BCE/ mM creatinine). When the groups receiving creatine were combined, they had a greater relative decrease in NTx compared to the protein group (−24±20% vs. +13±82%; p=0.05). CONCLUSIONS: Creatine supplementation during a resistance training program is beneficial for reducing bone catabolism in older men. Supported by Experimental and Applied Sciences (EAS)

Randomized Controlled Trial of Dietary Creatine as an Adjunct Therapy to Physical Training in Chronic Obstructive Pulmonary Disease

Skeletal muscle strength and bulk are reduced in patients with chronic obstructive pulmonary disease (COPD) and influence quality of life, survival, and utilization of health care resources. Exercise training during pulmonary rehabilitation (PR) can reverse some of these effects. In athletes and healthy elderly individuals, dietary creatine supplementation (CrS) has been shown to augment high-intensity exercise training, thereby increasing muscle mass. This article examines the effect of CrS on functional exercise capacity and muscle performance in people with COPD. One hundred subjects with COPD (mean [SD] age, 68.2 [8.2] yr; FEV(1), 44.0 [19.6] %predicted) were randomized to a double-blind, placebo-controlled, parallel group trial of CrS during 7 weeks of PR encompassing aerobic and resistance exercises. Subjects ingested creatine (22 g/d loading for 5 d; maintenance, 3.76 g/d throughout PR) or placebo. Baseline, postloading, and postrehabilitation measurements included pulmonary function, body composition, peripheral muscle strength, and functional performance (shuttle walking tests). A volunteer subgroup (n = 44) had pre- and postloading quadriceps muscle biopsies. Eighty subjects completed the trial (38 creatine, 42 placebo). All outcome measures significantly improved after PR. There were no significant differences between groups post-PR (mean [SD] change in incremental shuttle walk distance, 84 [79] m in the creatine group vs. 83.8 [60] m in the placebo group; P = 1.0; knee extensor work, 19.2 [16] Nm [Newton meters] in the creatine group vs. 19.5 [17] Nm in the placebo group; P = 0.9). Muscle biopsies showed evidence of creatine uptake. This adequately powered, randomized, placebo-controlled trial shows that CrS does not augment the substantial training effect of multidisciplinary PR for patients with COPD. Clinical trial registered with https://portal.nihr.ac.uk/Pages/NRRArchiveSearch.aspx (NO123138126).

Multiscale and Modular Analysis of Cardiac Energy Metabolism

Computational models of large molecular systems can be assembled from modules representing biological function emerging from interactions among a small subset of molecules. Experimental information on isolated molecules can be integrated with the response of the network as a whole to estimate crucial missing parameters. As an example, a “skeleton” model is analyzed for the module regulating dynamic adaptation of myocardial oxidative phosphorylation (OxPhos) to fluctuating cardiac energy demand. The module contains adenine nucleotides, creatine, and phosphate groups. Enzyme kinetic equations for two creatine kinase (CK) isoforms were combined with the response time of OxPhos (tmito; generalized time constant) to steps in the cardiac pacing rate to identify all module parameters. To obtain tmito, the time course of O2 uptake was measured for the whole heart. An O2 transport model was used to deconvolute the whole‐heart response to the mitochondrial level. By optimizing mitochondrial outer membrane permeability to 21 μm/s the experimental tmito = 3.7 s was reproduced. This in vivo value is about four times larger, or smaller, respectively, than conflicting values obtained from two different in vitro studies. This demonstrates an important rule for multiscale analysis: experimental responses and modeling of the system at the larger scale allow one to estimate essential parameters for the interfaces of components which may have been altered during physical isolation. The model correctly predicts a smaller tmito when CK activity is reduced. The model further predicts a slower response if the muscle CK isoform is overexpressed and a faster response if mitochondrial CK is overexpressed. The CK system is very effective in decreasing maximum levels of ADP during systole and reducing average Pi levels over the whole cardiac cycle.

Central Adaptations to Creatine Supplementation in Young Individuals

Creatine supplementation improves cognitive and psychomotor function in young subjects following 24 hours of sleep deprivation, possibly by increasing brain creatine or improving cerebral oxygenation. It has also been demonstrated that creatine supplementation may improve cognitive processing in non-sleep deprived subjects when assessed with a limited number of cognitive tests. However, the effects of creatine supplementation on cognitive processing in non-sleep deprived individuals has not been assessed with a comprehensive battery of neurocognitive tests. PURPOSE: To examine the effects of creatine supplementation on cognitive processing in young adults. METHODS: Twenty-two subjects (13 males, 9 females; 21 ± 2 yr) ingested creatine or placebo (0.03 g/kg of body mass per day) for 6 weeks in a double-blind placebo-controlled fashion. Subjects completed a battery of neurocognitive tests using Automated Neuropsychological Assessment Matrices (ANAM) pre- and post-supplementation. The cognitive test battery consisted of: simple reaction time (RT), code substitution (CS), code substitution delayed (CSD), logical reason symbolic (LRS), mathematical processing (MP), running memory (RM), and Sternberg memory recall (MR). Response time for correct responses (msec), response time for all responses (msec), accuracy, and throughput (correct responses/min) were assessed. Data were analyzed with a 2 × 2 repeated measures ANOVA. RESULTS: There were no significant group by time interactions for RT, CSD, LRS, MP, RM, and MR (all p>0.05). There was a significant group by time interaction for CS (p=0.03). Post hoc analyses indicated that this resulted from a combination of a performance decrement in the placebo group and a performance increase in the creatine group. CONCLUSION: Six weeks of creatine supplementation does not improve cognitive processing in young adults.

Creatine supplements in patients with idiopathic inflammatory myopathies who are clinically weak after conventional pharmacologic treatment: Six‐month, double‐blind, randomized, placebo‐controlled trial

To test the hypothesis that oral creatine supplements with exercise are more effective than exercise alone in improving muscle function in patients with established dermatomyositis or polymyositis receiving chronic medical therapies who are clinically weak yet stable. In a 6-month, 2-center, double-blind, randomized controlled trial, patients were randomized to receive oral creatine supplements (8 days, 20 gm/day then 3 gm/day) or placebo. All patients followed a home exercise program. The primary outcome was aggregate functional performance time (AFPT), reflecting the ability to undertake high-intensity exercise. Secondary outcomes included a functional index measuring endurance and muscle bioenergetics on (31)P magnetic resonance spectroscopy ((31)P MRS). Patients were receiving stable immunosuppressive treatment and/or corticosteroids. A total of 37 patients with polymyositis or dermatomyositis were randomized (19 to creatine, 18 to placebo); 29 completed 6 months. Intent-to-treat analyses demonstrated that AFPT improved significantly at 6 months with creatine (median decrease 13%, range -32-8%) compared with placebo (median decrease 3%, range -13-16%; P = 0.029 by Mann-Whitney U test). A completer analysis also showed significant benefits from creatine (P = 0.014). The functional index improved significantly with both creatine and placebo (P < 0.05 by paired Wilcoxon's rank sum test), with a significant benefit between groups in the completer analysis only. Phosphocreatine/beta-nucleoside triphosphate ratios using MRS increased significantly in the creatine group (P < 0.05) but not in the control group. No clinically relevant adverse events were associated with creatine. Oral creatine supplements combined with home exercises improve functional performance without significant adverse effects in patients with polymyositis or dermatomyositis. They appear safe, effective, and inexpensive.

A Randomized, Placebo-Controlled Trial of Creatine in Children With Spinal Muscular Atrophy

ABSTRACT Objective: To determine whether oral creatine produces positive changes in any of 4 outcomes in children with spinal muscular atrophy (SMA). Methods: The authors conducted a randomized, double-blind, placebo-controlled trial on 55 patients aged 2-18 years with SMA. Patients aged younger than 5 years received 2 g/day of creatine/placebo for 6 months. Patients aged 5 years and older received 5 g/day. The primary outcome measure was the Gross Motor Function Measure (GMFM). Secondary outcome measures were Quantitative Muscle Testing (QMT), Parent Questionnaire for the PedsQL™ Neuromuscular Module (QOL), and Pulmonary Function Tests (PFT). Results: Forty of the 55 patients completed the protocol. There was no significant difference in the 4 outcome measures between creatine and placebo groups. Conclusions: Under the experimental conditions of our study, creatine supplementation for 6 months did not improve motor function, muscle strength, pulmonary function, or quality of life in children with SMA,

Creatine and tempol attenuate noise-induced hearing loss

To define the role of free radical formation and potential energy depletion in noise induced hearing loss (NIHL), we measured the effectiveness of tempol (free radical scavenger) and creatine (enhances cellular energy storage) alone and in combination to attenuate NIHL. Guinea pigs were divided into four treatment groups: controls, 3% creatine diet (2 weeks prior to noise exposure), tempol (3 mM in drinking water 2 weeks prior to exposure), and creatine plus tempol and exposed to 120 dB SPL one-octave band noise centered at 4 kHz for 5 h. The noise-only control group showed frequency-dependent auditory threshold shifts (measured by auditory brainstem response, ABR) of up to 73 dB (16 kHz) on day 1, and up to 50 dB (8 kHz) on day 10. Creatine-treated subjects had significantly smaller ABR threshold shifts on day 1 and on day 10. Tempol alone significantly reduced ABR threshold shifts on day 10 but not on day 1. ABR shifts after combination treatment were similar to those in the creatine group. Hair cell loss on day 10 was equally attenuated by creatine and tempol alone or in combination. Our results indicate that the maintenance of ATP levels is important in attenuating both temporary and permanent NIHL, while the scavenging of free radicals provides protection from permanent NIHL.

Effects of Creatine Supplementation and Three Days of Resistance Training on Muscle Strength, Power Output, and Neuromuscular Function

Previous studies have demonstrated increases in peak torque (PT) and decreases in acceleration time (ACC) after only 2 days of resistance training, and other studies have reported improvements in isokinetic performance after 5 days of creatine supplementation. Consequently, there may be a combined benefit of creatine supplementation and short-term resistance training for eliciting rapid increases in muscle strength, which may be important for short-term rehabilitation and return-to-play for previously injured athletes. The purpose of this study, therefore, was to examine the effects of 3 days of isokinetic resistance training combined with 8 days of creatine monohydrate supplementation on PT, mean power output (MP), ACC, surface electromyography (EMG), and mechanomyography (MMG) of the vastus lateralis muscle during maximal concentric isokinetic leg extension muscle actions. Twenty-five men (mean age +/- SD = 21 +/- 3 years, stature = 177 +/- 6 cm, and body mass = 80 +/- 12 kg) volunteered to participate in this 9-day, double-blind, placebo-controlled study and were randomly assigned to either the creatine (CRE; n = 13) or placebo (PLA; n = 12) group. The CRE group ingested the treatment drink (280 kcal; 68 g carbohydrate; 10.5 g creatine), whereas the PLA group received an isocaloric placebo (70 g carbohydrate). Two servings per day (morning and afternoon) were administered in the laboratory on days 1-6, with only 1 serving on days 7-8. Before (pre; day 1) and after (post; day 9) the resistance training, maximal voluntary concentric isokinetic leg extensions at 30, 150, and 270 degrees x s(-1) were performed on a calibrated Biodex System 3 dynamometer. Three sets of 10 repetitions at 150 degrees x s(-1) were performed on days 3, 5, and 7. Peak torque increased (p = 0.005; eta(2) = 0.296), whereas ACC decreased (p < 0.001; eta(2) = 0.620), from pretraining to posttraining for both the CRE and PLA groups at each velocity (30, 150, and 270 degrees x s(-1)). Peak torque increased by 13% and 6%, whereas ACC decreased by 42% and 34% for the CRE and PLA groups, respectively, but these differences were not statistically significant (p > 0.05). There were no changes in MP, EMG, or MMG amplitude; however, EMG median frequency (MDF) increased, and MMG MDF increased at 30 degrees x s(-1), from pretraining to posttraining for both the CRE and PLA groups. These results indicated that 3 days of isokinetic resistance training was sufficient to elicit small, but significant, improvements in peak strength (PT) and ACC for both the CRE and PLA groups. Although the greater relative improvements in PT and ACC for the CRE group were not statistically significant, these findings may be useful for rehabilitation or strength and conditioning professionals who may need to rapidly increase the strength of a patient or athlete within 9 days.

Creatine supplementation and physical training in patients with COPD: A double blind, placebo-controlled study

Patients with chronic obstructive pulmonary disease (COPD) have low exercise capacity and low content of high energetic phosphates in their skeletal muscles. The aim of the present study was to investigate whether creatine supplementation together with exercise training may increase physical performance compared with exercise training in patients with COPD. In a randomized, double-blind, placebo-controlled study, 23 patients with COPD (forced expiratory volume in one second [FEV1] < 70% of predicted) were randomized to oral creatine (n = 13) or placebo (n = 10) supplementation during an 8-week rehabilitation programme including exercise training. Physical performance was assessed by Endurance Shuttle Walking Test (ESWT), dyspnea and leg fatigue with Borg CR- 10, quality of life with St George's Respiratory Questionnaire (SGRQ). In addition, lung function test, artery blood gases, grip strength test, muscle strength and fatigue in knee extensors were measured. COPD patients receiving creatine supplementation increased their average walking time by 61% (ESWT) (p < 0.05) after the training period compared with 48% (p = 0.07) in the placebo group. Rated dyspnea directly after the ESWT decreased significantly from 7 to 5 (p < 0.05) in the creatine group. However, the difference between the groups was not statistically significant neither in walking time nor in rated dyspnea. Creatine supplementation did not increase the health related quality of life, lung function, artery blood gases, grip strength and knee extensor strength/fatigue. Oral creatine supplementation in combination with exercise training showed no significant improvement in physical performance, measured as ESWT, in patients with COPD compared with exercise training alone.

Creatine supplementation, sleep deprivation, cortisol, melatonin and behavior

The effect of creatine supplementation and sleep deprivation, with intermittent moderate-intensity exercise, on cognitive and psychomotor performance, mood state, effort and salivary concentrations of cortisol and melatonin were examined. Subjects were divided into a creatine supplementation group and a placebo group. They took 5 g of creatine monohydrate or a placebo, dependent on their group, four times a day for 7 days immediately prior to the experiment. They undertook tests examining central executive functioning, short-term memory, choice reaction time, balance, mood state and effort at baseline and following 18-, 24- and 36-h sleep deprivation, with moderate intermittent exercise. Saliva samples were taken prior to each set of tests. A group × time analysis of covariance, with baseline performance the covariate, showed that the creatine group performed significantly ( p < 0.05) better than the placebo group on the central executive task but only at 36 h. The creatine group demonstrated a significant ( p < 0.01) linear improvement in performance of the central executive task throughout the experiment, while the placebo group showed no significant effects. There were no significant differences between the groups for any of the other variables. A significant ( p < 0.001) main effect of time was found for the balance test with a linear improvement being registered. Cortisol concentrations on Day 1 were significantly ( p < 0.01) higher than on Day 2. Mood significantly ( p < 0.001) deteriorated up to 24 h with no change from 24 to 36 h. Effort at baseline was significantly ( p < 0.01) lower than in the other conditions. It was concluded that, during sleep deprivation with moderate-intensity exercise, creatine supplementation only affects performance of complex central executive tasks.

Effect of Creatine and ß-Alanine Supplementation on Performance and Endocrine Responses in Strength/Power Athletes

The effects of creatine and creatine plus beta-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine (C), or creatine plus beta-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C, however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus beta-alanine on strength performance. Creatine plus beta-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.