Creatine

Parkinson's disease (PD) has a progressive course and is characterized by the degeneration of dopaminergic neurons. Although no neuroprotective treatments for PD have been found to date, the endocannabinoid system has emerged as a promising target. From a sample of 119 patients consecutively evaluated in a specialized movement disorders outpatient clinic, we selected 21 PD patients without dementia or comorbid psychiatric conditions. Participants were assigned to three groups of seven subjects each who were treated with placebo, cannabidiol (CBD) 75 mg/day or CBD 300 mg/day. One week before the trial and in the last week of treatment participants were assessed in respect to (i) motor and general symptoms score (UPDRS); (ii) well-being and quality of life (PDQ-39); and (iii) possible neuroprotective effects (BDNF and H(1)-MRS). We found no statistically significant differences in UPDRS scores, plasma BDNF levels or H(1)-MRS measures. However, the groups treated with placebo and C...

THE SCIENCE OF fluid replacement in athletic training, particularly with regard to American football players, has advanced during the past 3 decades. This advance has resulted in substantial decreases in heatstroke-related deaths during summer training sessions. Recent trends in football heatstroke fatalities toward significant increases may, in part, be attributable to or aggravated by the use of dietary supplements. Credible scientific evidence has been found that amphetamine derivatives and the ergonomic aid creatine may contribute to subclinical dehydration and heatstroke in selected individuals. Caution is urged in the education and evaluation of football players who train during the hot summer months.

This study aims to investigate metabolic changes in frontal and parietal cortices in the 6-OHDA induced Parkinson's rats. Ratios of N-acetyl-aspartic acid/creatine (NAA/Cr), choline/creatine (Cho/Cr), and glumatic acid and glutamine glutaminic acid/creatine (Glx/Cr) of regions of interests (ROIs) in the frontal and parietal cortices, and the substantia nigra were analyzed. NAA/Cr, Cho/Cr and Glx/Cr in the frontal and parietal cortices in the lesion side did not show any significant differences two weeks after operation compared with the contralateral side ( p > 0.05). NAA/Cr in the frontal cortex in the lesion side was significantly lower in the five weeks after operation; Cho/Cr remained normal; Glx/Cr increased ( p < 0.05), and all ratios of parietal cortex were normal. In the eight weeks after operation, NAA/Cr in the frontal cortex in the lesion side was lower than that of the five weeks ( p < 0.01), Cho/Cr still remained normal while Glx/Cr was higher than before ( p < 0.01). Regarding the parietal cortex, NAA/Cr increased significantly, while Cho/Cr and Glx/Cr remained normal. In the 12 weeks after operation, NAA/Cr, Cho/Cr and Glx/Cr in frontal cortex were consistent with that of the eight weeks, while they remained at the normal level in parietal cortex. The NAA/Cr in the substantia nigra decreased and Cho/Cr increased significantly during 2-8 weeks, and remained at the same level during 8-12 weeks. There are metabolic disturbances in PD rats. The transient hyperfunction in the parietal cortex can be considered as a compensation for the dysfunction of the frontal cortex and substantia nigra. Int J Neurosci Downloaded from informahealthcare.com by University of British Columbia on 08/21/13 For personal use only. 2 Z. Hou et al. International Journal of Neuroscience Int J Neurosci Downloaded from informahealthcare.com by University of British Columbia on 08/21/13 For personal use only. International Journal of Neuroscience Int J Neurosci Downloaded from informahealthcare.com by University of British Columbia on 08/21/13 For personal use only.

The pharmacokinetics of oral quinidine sulfate and quinidlne gluconate were compared in seven healthy volunteers in a two part pharmacoklnetlc study. Part I was a single dose crossover trial assessing absorption and elimination of quinidine sulfate (400 mg, equivalen?to 331 mg of quinidine base) and quinidine gluconate (495 mg, equivalent to 309 mg of quinidlne base). Mean kinetic values for the sulfate and gluconate preparations, respectively, were: peak serum quinidine level 2.07 versus 1.24 hg/ml (P KO.025); time of peak concentration 1.61 versus 3.64 hours after the dose (P <0.02); first order absorption half-life 41.1 versus 61.2 minutes (P COO.1); elimination half-life 6.1 versus 6.3 hours (difference not significant); absolute systemic availability (based upon comparison with intravenous data from the same subjects) 66.0 versus 76.5 percent (difference not significant ) using area under the serum concentration curve, or 63.7 versus 73.6 percent (P <0.05) using cumulative 46 hour urinary excretion of qulnktine. The findings indicate that absorption of quinidine gluconate is slightly less complete but much less rapid than that of quinidine sulfate.

Stout, J.R., J.T. Cramer, M. Mielke, J. O'Kroy, D.J. Torok, and R.F. Zoeller. Effects of twenty-eight days of betaalanine and creatine monohydrate supplementation on the physical working capacity at neuromuscular fatigue threshold. J. Strength Cond. Res. 20(4):928-931. 2006.-The purpose of this study was to examine the effects of 28 days of beta-alanine (b-Ala) and creatine monohydrate (CrM) supplementation on the onset of neuromuscular fatigue by using the physical working capacity at neuromuscular fatigue threshold (PWC FT ) test in untrained men. Fifty-one men (mean age Ϯ SD ϭ 24.5 Ϯ 5.3 years) volunteered to participate in this 28-day, double-blind, placebocontrolled study and were randomly assigned to 1 of 4 groups: placebo (PLA; 34 g dextrose; n ϭ 13), CrM (5.25 g CrM plus 34 g dextrose; n ϭ 12), b-Ala (1.6 g b-Ala plus 34 g of dextrose; n ϭ 12), or b-Ala plus CrM (CrBA; 5.25 g CrM plus 1.6 g b-Ala plus 34 g dextrose; n ϭ 14). The supplement was ingested 4 times per day for 6 consecutive days, then twice per day for 22 days before posttesting. Before and after the supplementation, subjects performed a continuous incremental cycle ergometry test while a surface electromyographic signal was recorded from the vastus lateralis muscle to determine PWC FT . The adjusted mean posttest PWC FT values (covaried for pretest PWC FT values) for the b-Ala and CrBA groups were greater than those for the PLA group (p Յ 0.05). However, there were no differences between the CrM vs. PLA, CrBA vs. b-Ala, CrM vs. b-Ala, or CrM vs. CrBA groups (p Ͼ 0.05). These findings suggested that b-Ala supplementation may delay the onset of neuromuscular fatigue. Furthermore, there appeared to be no additive or unique effects of CrM vs. b-Ala alone on PWC FT .

In localized brain proton MR spectroscopy ( 1 H-MRS), metabolites' levels are often expressed as ratios, rather than as absolute concentrations. Frequently, their denominator is the creatine [Cr], which level is explicitly assumed to be stable in normal as well as in many pathologic states. The rationale is that ratios self-correct for imager and localization method differences, gain instabilities, regional susceptibility variations and partial volume effects. The implicit assumption is that these benefits are worth their cost ww propagation of the individual variation of each of the ratio's components. To test this hypothesis, absolute levels of N-acetylaspartate [NAA], choline [Cho] and [Cr] were quantified in various regions of the brains of 8 volunteers, using 3-dimensional (3D) 1 H-MRS at 1.5 T. The results show that in over 50% of ϳ2000 voxels examined, [NAA]/[Cr] and [Cho]/[Cr] exhibited higher coefficients of variations (CV) than [NAA] and [Cho]

Longitudinal (T,) and apparent transverse relaxation times (TJ of choline-containing compounds (Cho), creatinelphosphocreatine (Cr/PCr), and N-acetyl aspartate (NAA) were measured in vivo in human brain at 4 Tesla. Measurements were performed using a water suppressed stimulated echo pulse sequence with complete outside volume presaturation to improve volume localization at short echo times. T,-values of Cho (1.2 fi 0.1 s), Cr (1.6 f 0.3 s), and NAA (1.6 f 0.2 s) at 4 Tesla in occipital brain were only slightly larger than those reported in the literature at 1.5 Tesla. Thus, TR will not adversely affect the expected enhancement of signal-to-noise at 4 Tesla. Surprisingly, apparent T,-values of Cho (142 i 34 ms), Cr (140 -c 13 ms), and NAA (185 f 24 ms) at 4 Tesla were significantly smaller than those at 1.5 Tesla and further decreased when increasing the mixing interval TM. Potential contributing factors, such as diffusion in local susceptibility related gradients, dipolar relaxation due to intracellular paramagnetic substances and motion effects are discussed. The results suggest that short echo time spectroscopy is advantageous to maintain signal to noise at 4 Tesla.

The objective was to assess the possibility of measuring urine creatinine (UCr)-adjusted urinary cell-free (ucf) DNA concentration as a noninvasive screening tool for bladder cancer. Using PicoGreen-based detection, the ucf-DNA/UCr concentration was quantified in urine supernatant specimens from 46 bladder cancer patients and 98 controls and compared to 400-bp real-time PCR-based detection, which detected the amplification of 400-bp beta-actin (named 400-bp ucf-DNA/UCr). The mean concentrations for both PicoGreen and 400-bp ucf-DNA (ng/mL)/UCr (mg/dL) were significantly higher in bladder cancer patients than in controls: 15.28 vs 6.68 (p&lt;0.001, t-test) and 14.98 vs 1.07 (p&lt;0.001), respectively. Among different stages and grades, no significant difference was found between these two methods. The areas under the ROC curves of PicoGreen and 400-bp ucf-DNA/UCr were 0.571 (95% confidence interval, 0.451-0.692) and 0.805 (95% confidence interval, 0.713-0.896), respectively. In 400-b...

This chapter summarizes the peer-reviewed literature of proton magnetic resonance spectroscopy ( 1 H MRS) studies on the effects of chronic and excessive alcohol consumption in both the animal and human brain. After a brief summary of the neuropathology of alcohol use disorders (AUD), we describe the primary brain metabolites measured by in vivo 1 H MRS. We then focus on published MRS studies of animal models of alcohol dependence and of treatment-seeking humans with AUD. We also summarize the scant MRS research on the much larger fraction of treatment-naïve individuals with AUD and the similarities and discrepancies relative to treatment-seekers. It is exceedingly apparent that premorbid and/or comorbid disorders/conditions, especially chronic smoking, among individuals with AUD contribute to the considerable variability in the pattern and magnitude of neurobiological and neurocognitive abnormalities in AUD. Therefore, we also review studies on the neurobiological consequences of the combined effects of chronic drinking and smoking in AUD. Finally, as AUD is characterized by a chronically relapsing/remitting course over lifetime and identification of those at greatest risk for relapse is important, we review 1 H MRS studies on brain spectroscopic measures that contribute to the prediction of relapse in AUD. We conclude with an overall assessment of the MRS research literature on brain alcohol effects, the role of animal and human studies in understanding the disease, and discuss the need of widely integrative MRS studies of cohorts that include individuals with comorbidies that are reflective of the general population with AUD.

Objective: To estimate the usefulness of 2-h creatinine clearance (CrCl) in the ICU and define variables that may reduce agreement. Design: Prospective study. Setting: Polyvalent ICU of a university hospital. Patients: 359 patients. Interventions: We compared 24-h CrCl (CrCl-24h), as the standard measure, with 2-h CrCl (CrCl-2h) (at the start of the period) and the Cockroft-Gault equation (Ck-G). Measurements and results:

The goal of our study was to perform a multisite evaluation of a new urine dipstick called Multistix PRO™ (Bayer, Elkhart, IN), which has reagent pads for the simultaneous assay of urinary albumin, protein, and creatinine. Patients' urine specimens were assayed at four sites with these dipsticks and with the familiar Bayer Multistix® 10SG dipsticks for protein. The new dipstick pads for albumin are impregnated with bis (3′,3″-diiodo-4′,4″dihydroxy-5′,5″-dinitrophenyl)-3,4,5,6-tetrabromo-sulfonephthalein (DIDNTB) dye. These dipsticks also have a novel pad that estimates urinary creatinine using the peroxidase activity of the copper-creatinine complex. We determined the interlaboratory agreement of these dipsticks by comparing dipstick results to values obtained by quantitative analytical methods. We found that dividing the dipsticks' albumin or protein results by the creatinine concentration reduced the number of false-positive albumin or protein values observed in concentrated urines, and reduced the number of false negatives in dilute urines. The ratio of albumin to creatinine, or protein to creatinine gives a better measure of albumin or protein excretion. Compared to reading by eye, the dipstick results agreed better with the quantitative assays when they were read by a reflectometer (Bayer Clinitek). J. Clin. Lab. Anal. 15:231-235, 2001.

Parkinson&#39;s disease (PD) has a progressive course and is characterized by the degeneration of dopaminergic neurons. Although no neuroprotective treatments for PD have been found to date, the endocannabinoid system has emerged as a promising target. From a sample of 119 patients consecutively evaluated in a specialized movement disorders outpatient clinic, we selected 21 PD patients without dementia or comorbid psychiatric conditions. Participants were assigned to three groups of seven subjects each who were treated with placebo, cannabidiol (CBD) 75 mg/day or CBD 300 mg/day. One week before the trial and in the last week of treatment participants were assessed in respect to (i) motor and general symptoms score (UPDRS); (ii) well-being and quality of life (PDQ-39); and (iii) possible neuroprotective effects (BDNF and H(1)-MRS). We found no statistically significant differences in UPDRS scores, plasma BDNF levels or H(1)-MRS measures. However, the groups treated with placebo and C...

Aims: This study investigated the effects of creatine and L-carnitine supplementation on anaerobic performance and body weight changes in athletes. Methods: In this single-blind randomized clinical trial, 45 athletes were selected and randomly divided into four groups supplemented with: a) Creatine, b) L-carnitine, c) Creatine- L- carnitine and D) placebo. The supplementation period was 28 days. Wingate anaerobic test was done for assessing athletes' anaerobic performance and their weights were measured before and after the supplementation period. To compare the variables before and after each test, paired t-test and anova are used compare within and between variables respecdivey. Results: The anaerobic performance indices in the groups receiving creatine and creatine- L-carnitine were significantly increased after intervention. Body weights were also significantly increased in the supplemented groups. Conclusions: Based on the dosage and duration of supplementation in this study, concurrent creatine and L-carnitine supplementation has positive effects on anaerobic performance. Despite L-carnitine is a weight loss agent, the findings of this study showed weight gain in the supplemented groups.

There has been interest in the use of exogenous creatine (Cr) as an adjunct treatment for neurological disorders. Creatine enhances bouts of activity through augmenting phosphocreatine for increased synthesis of ATP; however, multiple sclerosis (MS) individuals suffering from muscle weakness have not been shown to improve muscle work after 5 days of Cr supplementation. This study's purpose was to determine whether the extended duration would increase muscle capacity. In a double-blind, crossover trial, with a 3-week washout period, eleven MS subjects were randomly assigned to either Cr (5 g 4/day, day 1-7: 2.5 g 2/day, day 8-14) or placebo groups for two 14-day periods. Biodex Dynamometer recorded total work and power over three bouts of 30 maximal knee extensions and flexions. Total work was nonsignificant with Cr for knee extension (pretest 1277.7

Creatine and creatine phosphate provide storage and transmission of phosphate-bound energy in muscle and brain. Of the three inborn errors of creatine metabolism causing brain creatine depletion, L-arginine:glycine amidinotransferase (AGAT) deficiency has been described in only two families. We describe clinical and biochemical features, magnetic resonance spectroscopy (MRS) findings and response to creatine supplementation in two siblings with a novel mutation in the AGAT-encoding GATM gene. The sister and brother were evaluated at age 12 and 18 years, respectively, because of mild mental retardation, muscle weakness and low weight. Extensive work-up had previously yielded negative results. Electron microscopy of the muscle revealed tubular aggregates and the activity of respiratory chain complexes was decreased in the muscle. Urine organic acid concentrations normalized to urine creatinine concentration were all increased, suggesting a creatine metabolism disorder. Brain MRS was remarkable for absence of creatine. Urine guanidinoacetate levels by tandem mass spectrometry were low, suggesting AGAT deficiency. GATM sequencing revealed a homozygous single nucleotide insertion 1111_1112insA, producing a frame-shift at Met-371 and premature termination at codon 376. Eleven months after commencing treatment with oral creatine monohydrate 100 mg/kg/day, repeat MRI/MRS showed significantly increased brain creatine in the sister and a slight increase in the older brother. The parents' impression of improved strength and stamina was substantiated by increased post-treatment versus pre-treatment scores in the Vineland Adaptive Behavior Scale, straight-arm raising and timed up-and-go tests. Similarly, there was an apparent improvement in cognitive function, with significantly increased IQ-scores in the sister and marginal improvement in the brother.

Kreider, RB, and Greenwood, M. The effects of creatine monohydrate supplementation with and without D-pinitol on resistance training adaptations. J Strength Cond Res 23(9): 2673-2682, 2009-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 doubleblind 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 21 for 5 days) before ingesting 5 g/d 21 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.

The effect of the distribution of rest periods on the efficacy of interval sprint training is analysed. Ten male subjects, divided at random into two groups, performed distinct incremental sprint training protocols, in which the muscle load was the same (14 sessions), but the distribution of rest periods was varied. The`short programme' group (SP) trained every day for 2 weeks, while the`long programme' group (LP) trained over a 6-week period with a 2-day rest period following each training session. The volunteers performed a 30-s supramaximal cycling test on a cycle ergometer before and after training. Muscle biopsies were obtained from the vastus lateralis before and after each test to examine metabolites and enzyme activities. Both training programmes led to a marked increase (all signi®cant, P < 0.05) in enzymatic activities related to glycolysis (phosphofructokinase ± SP 107%, LP 68% and aldolase ± SP 46%, LP 28%) and aerobic metabolism (citrate synthase ± SP 38%, LP 28.4% and 3-hydroxyacyl-CoA dehydrogenase ± SP 60%, LP 38.7%). However, the activity of creatine kinase (44%), pyruvate kinase (35%) and lactate dehydrogenase (45%) rose signi®cantly (P < 0.05) only in SP. At the end of the training programme, SP had suffered a signi®cant decrease in anaerobic ATP consumption per gram muscle (P < 0.05) and glycogen degradation (P < 0.05) during the post-training test, and failed to improve performance. In contrast, LP showed a marked improvement in performance (P < 0.05) although without a signi®cant increase in anaerobic ATP consumption, glycolysis or glycogenolysis rate. These results indicate that high-intensity cycling training in 14 sessions improves enzyme activities of anaerobic and aerobic metabolism. These changes are affected by the distribution of rest periods, hence shorter rest periods produce larger increase in pyruvate kinase, creatine kinase and lactate dehydrogenase. However, performance did not improve in a short training programme that did not include days for recovery, which suggests that muscle ®bres suffer fatigue or injury.

Fatigue sustained during short-term, high-intensity exercise in humans is associated with the inability of skeletal muscle to maintain a high rate of anaerobic ATP production from phosphocreatine hydrolysis. Ingestion of creatine monohydrate at a rate of 20 g/d for 5-6 d was shown to increase the total creatine concentration of human skeletal muscle by approximately 25 mmol/kg dry mass, some 30% of this in phosphorylated form as phosphocreatine. A positive relation was then shown between muscle creatine uptake and improvements in performance during repeated bouts of maximal exercise. However, there is no evidence that increasing intake &gt; 20-30 g/d for 5-6 d has any potentiating effect on creatine uptake or performance. In individuals in whom the initial total creatine concentration already approached 150 mmol/kg dry mass, neither creatine uptake nor an effect on phosphocreatine resynthesis or performance was found after supplementation. Loss of ATP during heavy anaerobic exercise...

Creatine monohydrate has become the supplement of choice for many athletes striving to improve sports performance. Recent data indicate that athletes may not be using creatine as a sports performance booster per se but instead use creatine chronically as a training aid to augment intense resistance training workouts. Although several studies have evaluated the combined effects of creatine supplementation and resistance training on muscle strength and weightlifting performance, these data have not been analyzed collectively. The purpose of this review is to evaluate the effects of creatine supplementation on muscle strength and weightlifting performance when ingested concomitant with resistance training. The effects of gender, interindividual variability, training status, and possible mechanisms of action are discussed. Of the 22 studies reviewed, the average increase in muscle strength (1, 3, or 10 repetition maximum [RM]) following creatine supplementation plus resistance training was 8% greater than the average increase in muscle strength following placebo ingestion during resistance training (20 vs. 12%). Similarly, the average increase in weightlifting performance (maximal repetitions at a given percent of maximal strength) following creatine supplementation plus resistance training was 14% greater than the average increase in weightlifting performance following placebo ingestion during resistance training (26 vs. 12%). The increase in bench press 1RM ranged from 3 to 45%, and the improvement in weightlifting performance in the bench press ranged from 16 to 43%. Thus there is substantial evidence to indicate that creatine supplementation during resistance training is more effective at increasing muscle strength and weightlifting performance than resistance training alone, although the response is highly variable.

The objective of this study was to develop a simple and sensitive LC method for the determination of creatine in aqueous solutions as well as in rat plasma using electrochemical detection. The chromatographic system consisted of a GP50 gradient pump, an ED40 pulsed electrochemical detector, and an AI-450 chromatography automation system (Dionex). The mobile phase consisted of a mixture of water, acetonitrile, 0.01 M sodium acetate, and 1.0 M sodium hydroxide (2.5:2.5:90:5, V/V/V/V) at a flow rate of 1.0 ml/min. The chromatographic separation was achieved at 45 8C on a column with a polyhydroxylated glucose and sulfonated stationary phase. The retention times of creatine and creatinine was 3.50 and 4.73 min, respectively, with creatine fully resolved from its major degradation product, creatinine. The standard curves were linear over the concentration range of 0 Á/20 mg/ml. Within-day and day-today relative standard deviations (R.S.D.) were less than 10%. This method was used to study dissolution characteristics of various creatine salts in water.

Herda, TJ, Beck, TW, Ryan, ED, Smith, AE, Walter, AA, Hartman, MJ, Stout, JR, and Cramer, JT. Effects of creatine monohydrate and polyethylene glycosylated creatine supplementation on muscular strength, endurance, and power output. J Strength Cond Res 23(3): 818-826, 2009-The purpose of this study was to examine the effects of a moderate dose of creatine monohydrate (CM) and two smaller doses of polyethylene glycosylated (PEG) creatine on muscular strength, endurance, and power output. Fifty-eight healthy men (mean 6 SD: age, 21 6 2 years; height, 176 6 6 cm; body mass [BM], 75 6 14 kg) volunteered and were randomly assigned to 1 of 4 groups: (a) placebo (PL; 3.6 g of microcrystalline cellulose; n = 15), (b) CM (5 g of creatine; n = 13), (c) small-dose PEG creatine (1.25 g of creatine: PEG 1.25 ; n = 14), or (d) moderatedose PEG creatine (2.50 g of creatine: PEG 2.50 ; n = 16). Testing was conducted before (pre-) and after (post-) a 30-day supplementation period. Measurements included body mass, countermovement vertical jump (CVJ) height, power output during the Wingate test (peak power [PP] and mean power [MP]), 1 repetition maximum bench press (1RM BP ), 1RM leg press (1RM LP ) strength, and repetitions to failure at 80% of the 1RM for bench press (REP BP ) and leg press (REP LP ). BM and MP (W) increased (p # 0.05) from pre-to postsupplementation for the CM group only, whereas 1RM BP and 1RM LP increased (p # 0.05) for the CM, PEG 1.25 , and PEG 2.50 groups. CVJ height (cm and cmÁkg 21 ), MP (WÁkg 21 ), PP (W and WÁkg 21 ), REP BP , and REP LP increased (p # 0.05) for all groups. These findings indicated that the recommended safe dose of 5 gÁd 21 of CM increased BM and improved muscle strength (1RM BP and 1RM LP ). Smaller doses of PEG creatine (1.25 and 2.50 gÁd 21 ) improved muscle strength (1RM BP and 1RM LP ) to the same extent as 5 gÁd 21 of CM, but did not alter BM, power output, or endurance. When compared to the PL group, neither CM nor PEG creatine supplementation improved peak power output (CVJ or PP), MP, or muscle endurance (REP BP or REP LP ). Thus, PEG creatine may have ergogenic effects that are comparable to those of CM, but with a smaller dose of creatine.

Purpose: To compare active versus passive recovery on performance and metabolism during a test of repeated-sprint ability. Methods: Nine males performed four repeated-sprint cycle tests (six 4-s sprints, every 25 s) in a randomized, counterbalanced order: two tests with active recovery (~32% V O 2max ) and two with passive recovery. Muscle biopsies were taken during the four tests from the vastus lateralis pretest, immediately posttest, and following 21 s of recovery to determine phosphocreatine ([PCr]), creatine, and muscle lactate concentration ([MLa j ]). Results: Active recovery resulted in a greater power decrement than passive recovery (7.4 T 2.2 vs 5.6 T 1.8%, P = 0.01) and lower final peak power (14.9 T 1.5 vs 15.3 T 1.5 WIkg j1 , P = 0.02). However, there was no significant difference in work decrement or total work. The percent of resting [PCr] was lower and approached significance posttest (32.6 T 10.6 vs 45.3 T 18.6%; P = 0.06; effect size (ES) = 0.8) and following 21 s of recovery (54.6 T 9.6 vs 71.7 T 14.1%; P = 0.06; ES = 1.2) during active recovery. The [MLa j ] was significantly higher posttest during active recovery (71.7 T 12.3 vs 55.2 T 15.7 mmolIkg j1 dm; P = 0.048; ES = 1.2); however, no significant differences were evident following 21 s of recovery (55.0 T 11.3 vs 48.4 T 16.7 mmolIkg j1 dm, P = 0.07; ES = 0.5).

Hoffman, J.R., J.R. Stout, M.J. Falvo, J. Kang, and N.A. Ratamess. Effect of low-dose, short-duration creatine supplementation on anaerobic exercise performance. J. Strength Cond. Res. 19(2):260-264. 2005.-To examine the efficacy of a low-dose, short-duration creatine monohydrate supplement, 40 physically active men were randomly assigned to either a placebo or creatine supplementation group (6 g of creatine monohydrate per day). Testing occurred before and at the end of 6 days of supplementation. During each testing session, subjects performed three 15-second Wingate anaerobic power tests. No significant (p Ͼ 0.05) group or time differences were observed in body mass, peak power, mean power, or total work. In addition, no significant (p Ͼ 0.05) differences were observed in peak power, mean power, or total work. However, the change in the rate of fatigue of total work was significantly (p Ͻ 0.05) lower in the creatine supplementation group than in the placebo group, indicating a reduced fatigue rate in subjects supplementing with creatine compared with the placebo. Although the results of this study demonstrated reduced fatigue rates in patients during high-intensity sprint intervals, further research is necessary in examining the efficacy of low-dose, short-term creatine supplementation.

Purpose: To determine whether low-dose creatine and protein supplementation during resistance training (RT; 3 dIwk j1 ; 10 wk) in older men (59-77 yr) is effective for improving strength and muscle mass without producing potentially cytotoxic metabolites (formaldehyde). Methods: Older men were randomized (double-blind) to receive 0.1 gIkg j1 creatine + 0.3 gIkg j1 protein (CP; n = 10), creatine (C; n = 13), or placebo (PLA; n = 12) on training days. Measurements before and after RT included lean tissue mass (air-displacement plethysmography), muscle thickness (ultrasound) of elbow, knee, and ankle flexors and extensors, leg and bench press strength, and urinary indicators of cytotoxicity (formaldehyde), myofibrillar protein degradation [3-methylhistidine (3-MH)], and bone resorption [cross-linked N-telopeptides of type I collagen (NTx)]. Results: Subjects in C and CP groups combined experienced greater increases in body mass and total muscle thickness than PLA (P G 0.05). Subjects who received CP increased lean tissue mass (+5.6%) more than C (+2.2%) or PLA (+1.0%; P G 0.05) and increased bench press strength (+25%) to a greater extent than C and PLA combined (+12.5%; P G 0.05). CP and C did not differ from PLA for changes in formaldehyde production (+24% each). Subjects receiving creatine (C and CP) experienced a decrease in 3-MH by 40% compared with an increase of 29% for PLA (P G 0.05) and a reduction in NTx (j27%) versus PLA (+13%; P = 0.05). Conclusions: Low-dose creatine combined with protein supplementation increases lean tissue mass and results in a greater relative increase in bench press but not leg press strength. Lowdose creatine reduces muscle protein degradation and bone resorption without increasing formaldehyde production.

Creatine has become one of the most popular dietary supplements in the sports nutrition market. The form of creatine that has been most extensively studied and commonly used in dietary supplements is creatine monohydrate (CM). Studies have consistently indicated that CM supplementation increases muscle creatine and phosphocreatine concentrations by approximately 15-40%, enhances anaerobic exercise capacity, and increases training volume leading to greater gains in strength, power, and muscle mass. A number of potential therapeutic benefits have also been suggested in various clinical populations. Studies have indicated that CM is not degraded during normal digestion and that nearly 99% of orally ingested CM is either taken up by muscle or excreted in urine. Further, no medically significant side effects have been reported in literature. Nevertheless, supplement manufacturers have continually introduced newer forms of creatine into the marketplace. These newer forms have been purported to have better physical and chemical properties, bioavailability, efficacy, and/or safety profiles than CM. However, there is little to no evidence that any of the newer forms of creatine are more effective and/or safer than CM whether ingested alone and/or in combination with other nutrients. In addition, whereas the safety, efficacy, and regulatory status of CM is clearly defined in almost all global markets; the safety, efficacy, and regulatory status of other forms of creatine present in today's marketplace as a dietary or food supplement is less clear.

With the growing interest in the potential health benefits of plant-based diets, it is relevant to consider whether vegetarian dietary practices could influence athletic performance. Accordingly, this review examines whether nutrients that may differ between vegetarian and omnivorous diets could affect physical performance. We also describe recent studies that attempt to assess the effects of a vegetarian diet on performance and comment on other nutritional aspects of vegetarianism of relevance to athletes. Although well-controlled long-term studies assessing the effects of vegetarian diets on athletes have not been conducted, the following observations can be made: 1) well-planned, appropriately supplemented vegetarian diets appear to effectively support athletic performance; 2) provided protein intakes are adequate to meet needs for total nitrogen and the essential amino acids, plant and animal protein sources appear to provide equivalent support to athletic training and performance; 3) vegetarians (particularly women) are at increased risk for non-anemic iron deficiency, which may limit endurance performance; and 4) as a group, vegetarians have lower mean muscle creatine concentrations than do omnivores, and this may affect supramaximal exercise performance. Because their initial muscle creatine concentrations are lower, vegetarians are likely to experience greater performance increments after creatine loading in activities that rely on the adenosine triphosphate/phosphocreatine system. 5) Coaches and trainers should be aware that some athletes may adopt a vegetarian diet as a strategy for weight control. Accordingly, the possibility of a disordered eating pattern should be investigated if a vegetarian diet is accompanied by unwarranted weight loss. Nutrition 2004;20:696 -703. ©Elsevier Inc. 2004

The purpose of this study was to examine the effects of creatine supplementation on the incidence of injury observed during 3-years of NCAA Division IA college football training and competition. In an open label manner, athletes participating in the 1998-2000 football seasons elected to take creatine or non-creatine containing supplements following workouts/practices. Subjects who decided to take creatine were administered 15.75 g of creatine for 5 days followed by ingesting an average of 5 g/day thereafter administered in 5-10 g doses. Creatine intake was monitored and recorded by research assistants throughout the study and ranged between 34-56% of players during the course of the study. Subjects practiced or played in environmental conditions ranging from 8-40 degrees C (mean 24.7 +/- 9 degrees C) and 19-98% relative humidity (49.3 +/- 17%). Injuries treated by the athletic training staff were recorded and categorized as cramping, heat/dehydration, muscle tightness, muscle strain...

Background: The CF transmembrane conductance regulator (CFTR), whose mutations cause cystic fibrosis (CF), depends on ATP for activation and transport function. Availability of ATP in the cell and even more in specific cellular microcompartments often depends on a functional creatine kinase system, which provides the 'energy buffer' phosphocreatine. Creatine supplementation has been shown to increase phosphocreatine levels, thus promoting muscle growth and strength in athletes and having protective effects in neuromuscular disorders. Aim: To test clinically, if creatine supplementation improves maximal isometric muscle strength (MIMS), lung function and CFTR channel activity in patients with CF, and to determine enzymatic activity of creatine kinase in respiratory epithelial cells. Methods: In an open-label pilot study 18 CF patients (8-18-year-old) with pancreatic insufficiency and mild to moderate lung disease received daily creatine supplementation during 12 weeks. Patients were monitored during 24-36 weeks. Enzymatic activity of creatine kinase was measured in primary epithelial cell cultures. Results: After creatine supplementation, there was no change in lung function and sweat electrolyte concentrations, possibly due to the very low creatine kinase activities detected in respiratory epithelia. However, the patients consistently showed signicantly increased MIMS (18.4%; P-0.0001), as well as improved general well-being, as assessed by a standardized questionnaire. Except for one patient with transient muscle pain, no side effects were reported. Conclusions: Our pilot study suggests, that creatine supplementation should be further evaluated as a possible clinically beneficial adjuvant therapy for patients with CF to increase muscle strength, bodyweight and well-being ᮊ

There is an extensive and still growing body of the literature supporting the efficacy of creatine (Cr) supplementation. In sports, creatine has been recognized as the most effective nutritional supplement in enhancing exercise tolerance, muscle strength and lean body mass. From a clinical perspective, the application of Cr supplementation is indeed exciting. Evidences of benefits from this supplement have been reported in a broad range of diseases, including myopathies, neurodegenerative disorders, cancer, rheumatic diseases, and type 2 diabetes. In addition, after hundreds of published studies and millions of exposures creatine supplementation maintains an excellent safety profile. Thus, we contend that the widespread application of this supplement may benefit athletes, elderly people and various patient populations. In this narrative review, we aimed to summarize both the ergogenic and therapeutic effects of Cr supplementation. Furthermore, we reviewed the impact of Cr supplementation on kidney function.

Objective: We evaluated whether colostrum (Col) or an isocaloric and isonitrogenous blend of whey and casein in addition to creatine (Cr) affects body composition, muscular strength and endurance, and anaerobic performance during resistance training. Methods: Forty-nine resistance-trained subjects participated in a standardized 12-wk total body resistance training program. In a double-blind and randomized manner, subjects supplemented their diet with a protein control (Pro), Pro/Col, Pro/Cr, or Col/Cr. Supplements were isocaloric and isonitrogenous and provided 60 g/d of casein/whey (Pro) or Col as the protein source. At 0, 8, and 12 wk of supplementation, subjects were weighed, had body composition determined using dualenergy X-ray absorptiometry (DXA), performed one-repetition maximum (1RM) and 80% of 1RM tests on the bench press and leg press, and 30-s anaerobic sprint capacity tests. Data (mean Ϯ SD) were analyzed by repeated measures analysis of variance and reported as raw data in all tables and as changes from baseline for all figures for the Pro, Pro/Col, Pro/Cr, and Col/Cr groups, respectively. Results: Resistance training increased 1RM strength, muscular endurance, and anaerobic sprint capacity equally in all groups. Significant main and interaction effects (P Ͻ 0.05) were found for body mass, DXA total scanned mass, and fat-free mass (FFM; lean plus bone), whereas no changes (P Ͼ 0.05) were noted for fat mass, percent fat, or bone content. Post hoc analysis showed that, compared with Pro, subjects ingesting Pro/Col, Pro/Cr, and Col/Cr showed greater gains in body mass and DXA total scanned mass. Subjects ingesting Pro/Cr and Col/Cr had greater increases in FFM during training in comparison with Pro/Col. Conclusion: In conjunction with 12 wk of resistance training, ingestion of Col or a blend of whey and casein protein with a vitamin/mineral supplement containing Cr resulted in greater improvements in FFM in comparison with Pro and Pro/Col. (C. M. Kerksick).

The purpose of this study was to determine the safety and efficacy of consuming a preworkout supplement (SUP) containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days. We hypothesized that little to no changes in kidney and liver clinical blood markers or resting heart rate and blood pressure (BP) would be observed. In addition, we hypothesized that body composition and performance would improve in recreationally active males after 28 days of supplementation. In a double-blind, placebo-controlled study, participants were randomly assigned to ingest one scoop of either the SUP or placebo every day for 28 days, either 20 minutes before exercise or ad libitum on nonexercise days. Resting heart rate and BP, body composition, and fasting blood samples were collected before and after supplementation. Aerobic capacity as well as muscular strength and endurance were also measured. Significant (P < .05) main effects for time were observed for resting heart rate (presupplementation, 67.59 ± 7.90 beats per minute; postsupplementation, 66.18 ± 7.63 beats per minute), systolic BP (presupplementation, 122.41 ± 11.25 mm Hg; postsupplementation, 118.35 ± 11.58 mm Hg), blood urea nitrogen (presupplementation, 13.12 ± 2.55 mg/dL; postsupplementation, 15.24 ± 4.47 mg/dL), aspartate aminotransferase (presupplementation, 34.29 ± 16.48 IU/L; postsupplementation, 24.76 ± 4.71 IU/L), and alanine aminotransferase (presupplementation, 32.76 ± 19.72 IU/L; postsupplementation, 24.88 ± 9.68 IU/L). Significant main effects for time were observed for body fat percentage (presupplementation, 15.55% ± 5.79%; postsupplementation, 14.21% ± 5.38%; P = .004) and fat-free mass (presupplementation,

Twenty-nine (17 men, 12 women) collegiate track and field athletes were randomly divided into a creatine monohydrate (CM, n ϭ 10) group, creatine monohydrate and glutamine (CG, n ϭ 10) group, or placebo (P, n ϭ 9) group. The CM group received 0.3 g creatine·kg body mass per day for 1 week, followed by 0.03 g creatine·kg body mass per day for 7 weeks. The CG group received the same creatine dosage scheme as the CM group plus 4 g glutamine·day Ϫ1 . All 3 treatment groups participated in an identical periodized strength and conditioning program during preseason training. Body composition, vertical jump, and cycle performances were tested before (T1) and after (T2) the 8-week supplementation period. Body mass and lean body mass (LBM) increased at a greater rate for the CM and CG groups, compared with the P treatment. Additionally, the CM and CG groups exhibited significantly greater improvement in initial rate of power production, compared with the placebo treatment. These results suggest CM and CG significantly increase body mass, LBM, and initial rate of power production during multiple cycle ergometer bouts. . The effects of 8 weeks of creatine monohydrate and glutamine supplementation on body composition and performance measures.