Kreatyna - wzrost wytrzymałosci,siły i masy miesniowej

Stosowanie kreatyny otwiera nam swego rodzaju okienko siłowo-anaboliczno-antykataboliczne, które możemy wykorzystać - lub też nie.

W tym że okienku, możliwości naszego organizmu, do przyrostu siły, masy mięśniowej, jak i ochrony mięśni przed spadkiem zwiększają się - ale to nie znaczy że od samego stosowania kreatyny będziemy wyciskać na ławie 10kg więcej i w łapie przybędzie nam 2cm mięśni - niestety na to trzeba sobie zapracować.

Po odstawieniu tej substancji nasze okienko się zamyka, tym samym zmniejszając (a raczej przywracając do normalnego poziomu) podatność organizmu na wyżej wymienione parametry. Lecz nie jest to równoznaczne z tym, że wypracowane przez nas mięśnie czy siła ulegają zmniejszeniu. To co zdobyliśmy dzięki zbilansowanej diecie, ciężkiemu treningowi i należytej regeneracji jest nasze i tylko zaniedbując te trzy podstawowe aspekty możemy narazić się na jakże często omawiane spadki po cyklu.

https://www.sfd.pl/Kompendium_wiedzy_o_kreatynie-t521393.html


Kreatyna jest naturalnym zwiazkiem syntetyzowana glownie z argininy,glicyny i metioniny.

http://www.jbc.org/content/138/1/167.full.pdf html?ijkey=bd7b0effa708181799d953bcd932171789a4c0b4&keytype2=tf_ipsecsha

Mozna ja znalezc w miesie,rybach jak rowniez jest endogenicznie syntetyzowana przez czlowieka.
Srednia zawartosc kreatyny u 70kg osoby wynosi ~120g.
Z czesci tej puli powstaje kreatynina w ilosci 2g/dzien.
Wiekszosc z calkowitej puli kreatyny znajduje sie w miesniach - gdzie ~65% pod postacia fosfokretyny (Bierze udział w syntezie ATP, przekształcając się pod wpływem kinazy kreatynowej w kreatynę.)

Pierwsze badania odnosnie kreatyny w polaczeniu z treningiem - rok 1993!

Influence of oral creatine supplementation of muscle torque during repeated bouts of maximal voluntary exercise in man.

The present experiment was undertaken to investigate the influence of oral creatine supplementation, shown previously to increase the total creatine content of human skeletal muscle (Harris RC, Soderlund K, Hultman E. Clin Sci 1992; 83: 367-74), on skeletal muscle isokinetic torque and the accumulation of plasma ammonia and blood lactate during five bouts of maximal exercise. 2. Twelve subjects undertook five bouts of 30 maximal voluntary isokinetic contractions, interspersed with 1 min recovery periods, before and after 5 days of placebo (4 x 6 g of glucose/day, n = 6) or creatine (4 x 5 g of creatine plus 1 g of glucose/day, n = 6) oral supplementation. Muscle torque production and plasma ammonia and blood lactate accumulation were measured during and after exercise on each treatment. 3. No difference was seen when comparing muscle peak torque production during exercise before and after placebo ingestion. After creatine ingestion, muscle peak torque production was greater in all subjects during the final 10 contractions of exercise bout 1 (P < 0.05), throughout the whole of exercise bouts 2 (P < 0.01), 3 (P < 0.05) and 4 (P = 0.057) and during contractions 11-20 of the final exercise bout (P < 0.05), when compared with the corresponding measurements made before creatine ingestion. Plasma ammonia accumulation was lower during and after exercise after creatine ingestion. No differences were found when comparing blood lactate levels.

http://www.ncbi.nlm.nih.gov/pubmed/8504634?dopt=Abstract

suplementacja 20g kretyny (4x5g) przez 5 dni polepszyla wykonanie treningu i spadek wytrzymalosci o 6%.


Ciekawostki:
Suplementacja kreatyna jest bardziej 'skuteczniejsza' i efektywniejsza u osob z naturalnie mniejszymi zasobami kreatyny:

Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation.

Supplementation with 5g of creatine monohydrate, four or six times a day for 2 or more days resulted in a significant increase in the total creatine content of the quadriceps femoris muscle measured in 17 subjects. This was greatest in subjects with a low initial total creatine content and the effect was to raise the content in these subjects closer to the upper limit of the normal range. In some the increase was as much as 50%.

http://www.ncbi.nlm.nih.gov/pubmed/1327657?dopt=Abstract


Jak rowniez wieksza zawartosc kreatyny znajduje sie w wloknach miesniowych typu II - wiec im wiecej mamy takich wlokien - tym wiecej da nam kreatyna:

Creatine ingestion favorably affects performance and muscle metabolism during maximal exercise in humans

Nine male subjects performed two bouts of 30-s maximal isokinetic cycling before and after ingestion of 20 g creatine (Cr) monohydrate/day for 5 days. Cr ingestion produced a 23.1 +/- 4.7 mmol/kg dry matter increase in the muscle total creatine (TCr) concentration. Total work production during bouts 1 and 2 increased by approximately 4%, and the cumulative increases in both peak and total work production over the two exercise bouts were positively correlated with the increase in muscle TCr. Cumulative loss of ATP was 30.7 +/- 12.2% less after Cr ingestion, despite the increase in work production. Resting phosphocreatine (PCr) increased in type I and II fibers. Changes in PCr before exercise bouts 1 and 2 in type II fibers were positively correlated with changes in PCr degradation during exercise in this fiber type and changes in total work production. The results suggest that improvements in performance were mediated via improved ATP resynthesis as a consequence of increased PCr availability in type II fibers.

http://ajpendo.physiology.org/content/271/1/E31.abstract?ijkey=6964660968638c0dd4bc01d746b64785a05a6b50&keytype2=tf_ipsecsha

To ciekawe - u szczorow zawartosc kreatyny w wloknach szybkokurczliwych jest o 45% wieksza niz we wloknach wolnokurczliwych!



Kilka innych badan:

Creatine ingestion favorably affects performance and muscle metabolism during maximal exercise in humans

Nine male subjects performed two bouts of 30-s maximal isokinetic cycling before and after ingestion of 20 g creatine (Cr) monohydrate/day for 5 days. Cr ingestion produced a 23.1 +/- 4.7 mmol/kg dry matter increase in the muscle total creatine (TCr) concentration. Total work production during bouts 1 and 2 increased by approximately 4%, and the cumulative increases in both peak and total work production over the two exercise bouts were positively correlated with the increase in muscle TCr. Cumulative loss of ATP was 30.7 +/- 12.2% less after Cr ingestion, despite the increase in work production. Resting phosphocreatine (PCr) increased in type I and II fibers. Changes in PCr before exercise bouts 1 and 2 in type II fibers were positively correlated with changes in PCr degradation during exercise in this fiber type and changes in total work production. The results suggest that improvements in performance were mediated via improved ATP resynthesis as a consequence of increased PCr availability in type II fibers.

http://ajpendo.physiology.org/content/271/1/E31.abstract?ijkey=6964660968638c0dd4bc01d746b64785a05a6b50&keytype2=tf_ipsecsha

Wykonana praca maxymalna i calkowita byla wieksza o 4% po spozyciu kreatyny - niz przed spozyciem kretyny (4x5g przez 5dni)




jak rowniez straty ATP byly o 30.7% mniejsze po spozyciu kreatyny niz przed



Creatine supplementation enhances muscular performance during high-intensity resistance exercise.

OBJECTIVE: This study was undertaken to investigate the influence of oral supplementation with creatine monohydrate on muscular performance during repeated sets of high-intensity resistance exercise.

SUBJECTS/DESIGN: Fourteen active men were randomly assigned in a double-blind fashion to either a creatine group (n = 7) or a placebo group (n = 7). Both groups performed a bench press exercise protocol (5 sets to failure using each subject's predetermined 10-repetition maximum) and a jump squat exercise protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squat) on three different occasions (T1, T2, and T3) separated by 6 days.

INTERVENTION: Before T1, both groups received no supplementation. From T1 to T2, both groups ingested placebo capsules. From T2 to T3, the creatine group ingested 25 g creatine monohydrate per day, and the placebo group ingested an equivalent amount of placebo.

MAIN OUTCOME MEASURES: Total repetitions for each set of bench presses and peak power output for each set of jump squats were determined. Other measures included assessment of diet, body mass, skinfold thickness, and preexercise and 5-minute postexercise lactate concentrations.

RESULTS: Lifting performance was not altered for either exercise protocol after ingestion of the placebos. Creatine supplementation resulted in a significant improvement in peak power output during all 5 sets of jump squats and a significant improvement in repetitions during all 5 sets of bench presses. After creatine supplementation, postexercise lactate concentrations were significantly higher after the bench press but not the jump squat. A significant increase in body mass of 1.4 kg (range = 0.0 to 2.7 kg) was observed after creatine ingestion.

CONCLUSION: One week of creatine supplementation (25 g/day) enhances muscular performance during repeated sets of bench press and jump squat exercise.

http://www.ncbi.nlm.nih.gov/pubmed/9216554

tydzien suplementacji kreatyna (25g/dzien) spowodowalo znaczny wzrost sily i wytrzymalosci w porwonaniu do innych grup

ponadto suplemenatcja kreatyna spowodowala sredni wzrost masy ciala o 1,4kg (maxymalnie 2,7kg!)



Effects of creatine on isometric bench-press performance in resistance-trained humans.

PURPOSE: The purpose of this study was to investigate the effects of creatine (Cr) supplementation on force generation during an isometric bench-press in resistance-trained men.

METHODS: 32 resistance-trained men were matched for peak isometric force and assigned in double-blind fashion to either a Cr or placebo group. Subjects performed an isometric bench-press test involving five maximal isometric contractions before and after 5 d of Cr (20 g.d-1 Cr + 180 g.d-1 dextrose) or placebo (200 g.d-1 dextrose). Body composition was measured before and after supplementation. Subjects completed 24-h urine collections throughout the study period; these were subsequently analyzed to provide total Cr and creatinine excretion.

RESULTS: The amount of Cr retained over the supplementation period was 45 +/- 18 g (mean +/- SD), with an estimated intramuscular Cr storage of 43 (13-61) mmol x kg(-1) x dry weight muscle (median [range]). Four subjects in the Cr group were classified as "nonresponders" (< or =21 mmol x kg(-1) x dry weight muscle increase following Cr supplementation) and the remaining 17 subjects were classed as "responders" (> or =32 mmol x kg(-1) x dry weight muscle). For the Cr group, peak force and total force pre- or post-supplementation were not different from placebo. However, when the analysis was confined to the responders, both the change in peak force [Repetition 2: 59(81) N vs -26(85) N; Repetition 3: 45(59) N vs -26(64) N) and the change in total force (Repetition 1: 1471(1274) N vs 209(1517) N; Repetition 2: 1575(1254) N vs 196(1413) N; Repetition 3: 1278(1245) N vs -3(1118) N; Repetition 4: 918(935) N vs -83(1095) N] post-supplementation were significantly greater compared with the placebo group (P < 0.01). For the Cr group, estimated Cr uptake was inversely correlated with training status (r = -0.68, N = 21, P = 0.001). Cr significantly increased body weight (84.1 +/- 8.6 kg pre- vs 85.3 +/- 8.3 kg post-supplementation) and fat-free mass (71.8 +/- 6.0 kg pre- vs 72.6 +/- 6.0 kg post-supplementation), with the magnitude of increase being significantly greater in the responder group than in the placebo group.

CONCLUSION: Five days of Cr supplementation increased body weight and fat-free body mass in resistance-trained men who were classified as responders. Peak force and total force during a repeated maximal isometric bench-press test were also significantly greater in the responders compared to the placebo group

http://www.ncbi.nlm.nih.gov/pubmed/12131259

32 oosby zostaly podzielone na dwie grupy
-placebo przyjmujaca 200g dextrozy przez 5 dni
-grupe przyjmujaca kreatyne (CR) 20g + dextroze 180g przez 5dni

wnioski:
-wzrost wagi ciala u grupy CR o 1,2kg
-wzrost beztluszczowej masy o 0,8kg
-wzrost sily w porownaniu do grupy placebo


Creatine feeding increases GLUT4 expression in rat skeletal muscle

The purpose of this study was to investigate the potential role of creatine in GLUT4 gene expression in rat skeletal muscle. Female Wistar rats were fed normal rat chow (controls) or chow containing 2% creatine monohydrate ad libitum for 3 wk. GLUT4 protein levels of creatine-fed rats were significantly increased in extensor digitorum longus (EDL), triceps, and epitrochlearis muscles compared with muscles from controls (P < 0.05), and triceps GLUT4 mRNA levels were ∼100% greater in triceps muscles from creatine-fed rats than in muscles from controls (P < 0.05). In epitrochlearis muscles from creatine-fed animals, glycogen content was ∼40% greater (P < 0.05), and insulin-stimulated glucose transport rates were higher (P < 0.05) than in epitrochlearis muscles from controls. Despite no changes in [ATP], [creatine], [phosphocreatine], or [AMP], creatine feeding increased AMP-activated protein kinase (AMPK) phosphorylation by 50% in rat EDL muscle (P < 0.05). Creatinine content of EDL muscle was almost twofold higher for creatine-fed animals than for controls (P < 0.05). Creatine feeding increased protein levels of myocyte enhancer factor 2 (MEF2) isoforms MEF2A (∼70%, P < 0.05), MEF2C (∼60%, P < 0.05), and MEF2D (∼90%, P < 0.05), which are transcription factors that regulate GLUT4 expression, in creatine-fed rat EDL muscle nuclear extracts. Electrophoretic mobility shift assay showed that DNA binding activity of MEF2 was increased by ∼40% (P < 0.05) in creatine-fed rat EDL compared with controls. Our data suggest that creatine feeding enhances the nuclear content and DNA binding activity of MEF2 isoforms, which is concomitant with an increase in GLUT4 gene expression.

http://ajpendo.physiology.org/content/288/2/E347.abstract?sid=92a29ff4-28b1-4979-8353-6b2ee31ed6d0

szczury podzielono na dwie grupy
-kontrolna (PL)
-grupe spozywajaca kreatyne KR (2% zawartosc)

wnioski:
-GLUT4 byl wiekszy w grupie KR o ~100%
-poziom glikogenu byl o ~40% wiekszy w grupie KR
-wzrost AMPK wiekszy o ~50%

GLUT4 to transporter glukozy, ktory jest juz insulinozalezny, czyli insulina musi sie polaczyc z receptorem na komorce miesniowej lub tluszczowej - to receptor katalityczny IRS (Insuline Response System), ten powoduje wbudowanie transportera GLUT4 w blone komorkowa i zapewnia transport glukozy i kreatyny do komorek miesniowych.



Combined creatine and protein supplementation in conjunction with resistance training promotes muscle GLUT-4 content and glucose tolerance in humans.

The present study was undertaken to explore the effects of creatine and creatine plus protein supplementation on GLUT-4 and glycogen content of human skeletal muscle. This was investigated in muscles undergoing a decrease (immobilization) and subsequent increase (resistance training) in activity level, compared with muscles with unaltered activity pattern. A double-blind, placebo-controlled trial was performed by 33 young healthy subjects. The subjects' right legs were immobilized with a cast for 2 wk, followed by a 6-wk resistance training program for the right knee extensor muscles. The participants were supplemented throughout the study with either placebo (Pl group) or creatine (Cr group) or with creatine during immobilization and creatine plus protein during retraining (Cr+P group). Needle biopsies were bilaterally taken from the vastus lateralis. GLUT-4 protein expression was reduced by the immobilization in all groups (P < 0.05). During retraining, GLUT-4 content increased (P < 0.05) in both Cr (+24%) and Cr+P (+33%), which resulted in higher posttraining GLUT-4 expression compared with Pl (P < 0.05). Compared with Pl, muscle glycogen content was higher (P < 0.05) in the trained leg in both Cr and Cr+P. Supplements had no effect on GLUT-4 expression or glycogen content in contralateral control legs. Area under the glucose curve during the oral glucose tolerance test was decreased from 232 +/- 23 mmol. l(-1). min(-1) at baseline to 170 +/- 23 mmol. l(-1). min(-1) at the end of the retraining period in Cr+P (P < 0.05), but it did not change in Cr or Pl. We conclude that creatine intake stimulates GLUT-4 and glycogen content in human muscle only when combined with changes in habitual activity level. Furthermore, combined protein and creatine supplementation improved oral glucose tolerance, which is supposedly unrelated to the changes in muscle GLUT-4 expression.

http://www.ncbi.nlm.nih.gov/pubmed/12524381

badano trzy grupy:
-placebo (pl)
-grupe przyjmujaca kreatyne (KR)
-grupe przyjmujaca kreatyne + bialko (KR+B)

po 6-cio tygodniowym treningu jednej nogi (prawej) wyciagnieto wnioski:
-GLUT-4 wzrosl u grupy KR o 24% i u grupy KR+B o 33% w porownaniu do grupy placebo
-zawartosc glikogenu byla wieksza w obu grupach w porownianiu do grupy placebo - gdzie byla mniejsza
-te zmiany nie dotyczyly nogi lewej(!)

Stosowanie kreatyny lub kreatyny wraz z bialkiem przynosi korzystne efekty tylko (!) w polaczeniu z treningiem oporowym.


Efects of creatine supplementation and resistance training on muscle strength and weightlifting performance.

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.


http://www.ncbi.nlm.nih.gov/pubmed/14636102

po przebadaniu 22 artykułow na temat wplywu kreatyny na osoby cwiczace - wyciagnieto nastepujace wnioski:
-wzrost sily byl srenio o 8% wiekszy niz u grupy placebo
-wydolnosc wzrosla o 14% w porownaniu do grupy placebo

Zmieniony przez - solaros w dniu 2011-02-07 03:18:34

Athletic performance enhancement (enhanced muscle mass and muscle strength)
Several high-quality studies have shown an increase in muscle mass with the use of creatine. However, some weaker studies have reported mixed results. Overall, the available evidence suggests that creatine does increase lean body mass, strength, and total work. Future studies should take into account the effect of different individual fitness levels of study subjects.

Congestive heart failure (chronic)
Patients with chronic heart failure have low levels of creatine in their hearts. Several studies report that creatine supplements may improve heart muscle strength, body weight, and endurance in patients with heart failure. Studies comparing creatine with drugs used to treat heart failure are needed before a firm recommendation can be made. Heart failure should be treated by a qualified healthcare professional.

Kreatyna zwiększa wydolność mięśni (zwiększa masę i siłę mięśniową) w tym również zwiększa wydolność serca.

General: Creatine can be synthesized in the human body from dietary amino acids. Synthesis begins in the kidney when arginine and glycine form guanidoacetic acid. This product is methylated in the liver, forming creatine, technically known as methylguanidine-acetic acid. In a randomized controlled trial of creatine ingestion (20g daily for seven days, then 5g daily for 19 weeks), plasma guanidinoacetate levels were reduced by 50% after creatine loading and remained approximately 30% reduced throughout the maintenance phase. This decrease in circulating guanidinoacetate levels suggests that exogenous supply of creatine chronically inhibits endogenous synthesis at the transamidinase step in humans. This may lead to enhanced utilization of arginine as a substrate for secondary pathways.

Creatine kinase transfers the phosphate group from adenosine triphosphate (ATP) to creatine, thereby forming phosphocreatine plus adenosine diphosphate (ADP). This process is reversible in muscle cells and maintains the cellular ATP:ADP ratio. Creatine kinase is high in cells undergoing high-energy fluctuations, such as muscle cells, cardiac muscle cells, neurons, photoreceptor cells, and spermatozoa.

Antiaging: Creatine supplementation has a greater effect on phosphocreatine availability and resynthesis rate in middle-aged compared with younger persons. Aging is associated with lower total creatine and phosphocreatine concentrations and loading may be more efficient in subjects with a lower basal creatine level. To date creatine-induced effects of increased muscle strength, body mass, and performance have not been confirmed in studies on elderly subjects.

Antineoplastic: Creatine, like antioxidants, may upregulate apoptosis in preneoplastic and neoplastic cells. In vitro data suggest that cyclocreatine, a creatine kinase substrate analog, is cytotoxic to many solid tumors including human ME-180 cervical carcinoma. Addition of creatine and phosphocreatine analogs to the MCF-7 breast adenocarcinoma and the HT-29 colon adenocarcinoma cell lines delay the growth of rat mammary adenocarcinomas comparable to effects seen with currently used anticancer drugs. Nude mice transplanted with human colon adenocarcinoma cells given creatine demonstrated significant inhibition of tumor growth; the growth inhibition was directly correlated with creatine tissue concentrations. Cyclocreatine, an analog of creatine, was effective when added to standard anticancer agents including cis-diaminedichloroplatinum(II), cyclophosphamide, adriamycin, or 5-fluorouracil, and resulted in tumor-growth delay in SW2 small-cell lung cancer cells as compared with those obtained for each of the drugs alone and when administered to rats with mammary carcinoma.

Athletic performance enhancement: Myocytes use creatine to make phosphocreatine (PCr) via the enzyme creatine kinase (CK). PCr is used to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP). PCr also buffers intracellular hydrogen ions associated with lactate production and muscle fatigue during exercise. Thus, creatine may increase both the force of muscle contraction (by boosting ATP levels) and the duration of anaerobic exercise. During the first 10 seconds of intense exercise, creatine levels are markedly depleted. Creatine supplementation may accelerate PCr resynthesis following intense muscle contractions. Creatine supplementation has been shown to increase muscle creatine levels.

Body mass: In clinical trials, creatine has increased body mass. An increase in intracellular water has been suggested as a mechanism for increasing body mass.

Bone density: In one study examining the effect of creatine in the elderly, it was determined that creatine may increase bone density in combination with resistance training. The mechanism for this effect is unclear.

Cardiovascular: Creatine supplementation (15.75g daily for five days, then 5.25g daily for 20 days) resulted in reduced cholesterol, triglycerides, LDL cholesterol, and cholesterol/HDL (199). In a second randomized clinical trial, creatine supplementation decreased triacylglyceride levels (-26%; p<0.05), and VLDL-cholesterol levels (-26%, p<0.05). However, in another clinical trial, creatine had no effect on these lipid parameters. Exercise-induced myocardial ischemia is accompanied by increased serum creatine concentrations. No effect was noted on homocysteine levels in healthy individuals. Various clinical studies, case series, and randomized trials support the use of creatine supplementation for congestive heart failure.

Diabetes: In a controlled study, no changes were observed in those taking HMB plus creatine for six weeks. Decreased glucose levels in creatine-supplemented animals have been suggested. In humans, neither acute nor short-term creatine supplementation influenced glucose tolerance or levels. High concentrations of insulin may enhance muscle creatine accumulation. This is a result of an insulin-induced transport of creatine from circulation to skeletal muscle vs. creatine delivery. Decreased insulin levels in animals have been suggested. In humans, neither acute nor short-term creatine supplementation influenced measures of insulin sensitivity.

Exercise benefit: In some clinical trials, creatine improved exercise performance and/or endurance in cyclists, women athletes, high-intensity-sport athletes, rowers, squash and soccer players, and swimmers. However, untrained men taking creatine monohydrate did not have a significant difference in physical working capacity at neuromuscular fatigue threshold compared to placebo.

Huntington's disease: Creatine supplementation lowers levels of glutamate in the brain of patients with Huntington's disease. In animal models of Huntington's disease, induced by malonate poisoning, creatine supplements were neuroprotective, increasing brain concentrations of creatine and phosphocreatine. Creatine supplementation offered no benefit to Huntington's patients in a randomized clinical trial or in a case series.

Hyperornithemia: Creatine content in untreated gyrate atrophy patients was significantly reduced and supplementation improved levels dramatically. In a separate study, creatine supplementation was found to increase type 2 muscle fibers and improve visual field tests.

Increased lean body mass and strength (potential mechanisms): In clinical trials, some authors suggest that creatine increased strength, although not all authors agree. The increase in lean body mass often reported after creatine supplementation could be mediated by signaling pathways involving IgF and 4E-BP1. They found that timing of creatine supplement intake in relation to resistance exercise training can enhance lean body mass.

No change in muscle glycogen has been noted in animals supplemented with creatine. However, rats given creatine supplements chronically had a down regulation in the expression of creatine protein, which is responsible for creatine uptake into cells. Muscle glycogen loading capacity is influenced by its initial levels of creatine.

Creatine is osmotically active so it may redistribute water from extracellular fluids to muscle cells.

Creatine feeding increases GLUT4 gene expression in rat skeletal muscle. Creatine use has also been shown to offset the decline in GLUT4 observed during immobilization. In another study, creatine ingestion did not affect muscle GLUT4 expression.

When combined with heavy resistance training, creatine supplementation increases muscle creatine kinase mRNA expression, likely due to concomitant increases in the expression of myogenin and MRF-4.

Creatine loading has been suggested to facilitate the rate of muscle relaxation during brief isometric muscle contractions without affecting torque production.

Compared with placebo subjects, creatine subjects demonstrated significantly greater increases in Type 1, 2A, and 2AB muscle fiber cross-sectional areas. Creatine has been shown to stimulate Type 1, 2a, and 2x myosin heavy chain mRNA expression.

Ingesting creatine monohydrate increases the maximal accumulated oxygen deficit, which may be responsible for its ergogenic effect on supramaximal exercise performance.

In female athletes a higher physical working capacity at the fatigue threshold of the vastus lateralis muscle was noted by electromyographical measurement (186 watts vs. 155 watts with control; p<0.05).

Increased lean body mass and strength (unlikely mechanisms): AMP kinase probably is not implicated in the beneficial effects of oral creatine supplementation on muscle during immobilization and rehabilitative weight training. Although creatine supplementation increased muscle phosphocreatine concentration, muscle ATP cost of contraction was not affected. Creatine supplementation results in elevated phosphocreatine/adenosine triphosphate (ATP) ratios in the calf muscle of athletes.

Creatine does not reduce markers of muscle damage. Withdrawal from creatine had no effect on the rate of strength, endurance, and loss of lean tissue mass with 12 weeks of reduced-volume training.

Creatine supplementation does not enhance myofibrillar protein synthesis or diminish muscle protein breakdown. Creatine monohydrate supplementation does not increase whole body or mixed-muscle protein synthesis. Creatine had no effect on muscle protein synthesis or muscle protein breakdown. Thus, any increase in muscle mass accompanying creatine supplementation must be associated with increased physical activity.

Creatine loading raises muscle phosphocreatine concentration and improves performance during rapid and dynamic intermittent muscle contractions. However, creatine loading does not facilitate muscle phosphocreatine resynthesis during intermittent isometric muscle contractions.

Short-term creatine supplementation does not influence isometric elbow flexion force, muscle activation, stimulated contractile properties, or delay time to fatigue or improve recovery. A second study suggests creatine delays neuromuscular fatigue.

No measurable effect of creatine supplementation on respiratory gas exchange and blood lactate concentrations during either incremental submaximal exercise or recovery has been noted.

Mitochondrial diseases: In 15 patients with chronic progressive external ophthalmoplegia or Kearns-Sayre syndrome because of single large-scale mitochondrial DNA deletions, oral supplementation with creatine monohydrate did not significantly alter clinical scores and laboratory tests. There were no relevant changes on the phosphocreatine/ATP ratio at rest or post-exercise phosphocreatine recovery.

Multiple sclerosis: Elevated creatine in white matter of individuals with multiple sclerosis has been suggested to reflect microscopic inflammation, gliosis, or de- and remyelination. Results from one small randomized, double-blind clinical trial suggest that creatine supplementation does not improve work production in individuals with multiple sclerosis.

Myopathies: In a clinical trial, creatine transporter protein content was lower in individuals with various myopathies as compared to a control group. Mitochondrial creatine kinase was lower for inflammatory myopathy and congenital myopathy, higher for mitochondrial myopathy, and not different for muscular dystrophy. Creatine supplementation results in elevated phosphocreatine/adenosine triphosphate (ATP) ratios in the calf muscle of athletes, but not in patients with myopathies.

Neurological: In newborn rats, hypoxia-induced seizures were reduced by creatine injections. In a similar study, chronic administration of creatine ameliorated the extent of cortical damage by as much as 36% in mice and 50% in rats.

After taking a creatine supplement (8g daily for five days), repeated performance of simple mathematical calculations decreased cerebral oxygenated hemoglobin in the brains of subjects, suggesting increased oxygen utilization.

Lithium administration to healthy volunteers does not alter the choline/creatine ratio in the temporal lobe.

Neuromuscular and metabolic disorders: In animals with experimentally-induced Parkinsonism, creatine supplementation produced significant protection against loss of Nissl and tyrosine hydroxylase immunostained neurons in the substantia nigra. In vitro, creatine improved calcium mobilization and survival of skeletal muscle cells. Oral administration of creatine to G93A transgenic mice (who have significant mitochondrial dysfunction similar to amyotrophic lateral sclerosis (ALS)) led to dose-dependent improvement in motor performance and extended survival. Some, but not all, studies with patients with various muscular dystrophies show preliminary evidence supporting the use of creatine to alleviate these symptoms. Overall the evidence suggests that creatine supplementation does not offer benefit to individuals with ALS.

Vegetarian diet: Vegetarians have a lower muscle total creatine content and an increased capacity to load creatine into muscle following supplementation.

Źródło: FDA

Gdy byłem wege to kreatyna działała na mnie jak koks. Niesamowita pompa i wielki power na treningu. Przyrosty były na poziomie 5kg wagi(ale częściowo fatu) i z 15-20kg siły na ławie.
Niestety po odstawieniu miałem też spore spadki siły i masy.
Na razie mam przerwe wegetarianizmie i kreatyna działa na mnie dużo słabiej. Ledwo czuje jej działanie. Przyrosty są małe, ale nie ma spadków.
Z początku nie wiedziałem co się dzieje, jeszcze pół roku temu kreta kopała lepiej niż meta a teraz nic...

kreatyna to jedna z niewielu rzeczy ktorej dzialania nie trzeba udowadniac. Praktycznie kazde badanie wykazuje doza roznice przyrostow po zastosowaniu kreatyny. W przciwwienstwie do 99 % inney substancji

etios_ - zamieszczane informacje będą dużo bardziej przystępne, jeśli rozbudujesz choć symbolicznie polskojęzyczne "podsumowania" poszczególnych akapitów.

Warto też zamieszczać konkretne źródła, autorów itp, a jesli bibliografia jest zbyt obszerna - warto dać odnośnik do strony lub konkretny tytuł publikacji. Jeśli dobrze pamiętam wspominałem Ci już o tej konwencji.

Zmieniony przez - faftaq w dniu 2011-02-10 21:04:05

to prawda u mnie kreatyna kiedys bardzo pomagala w wydolnosci treningowej ( czasy na basenach na 100m )

teraz zauwazyl - w 1-wszym poscie jest delikatny blad - powinno byc
"suplementacja 20g kretyny (4x5g) przez 5 dni polepszyla wykonanie treningu i wzrost wytrzymalosci o 6%."

...a nie spadek


Zmieniony przez - solaros w dniu 2011-02-11 17:33:43

kilka badan na temat bezpieczenstwa jak rowniez skutecznych dawek:

Creatine: a review of efficacy and safety.

Although oral creatine supplementation is very popular among athletes, no prospective placebo-controlled studies on the adverse effects of long-term supplementation have yet been conducted. We performed a double-blind, placebo-controlled trial of creatine monohydrate in patients with the neurodegenerative disease amyotrophic lateral sclerosis, because of the neuroprotective effects it was shown to have in animal experiments. The purpose of this paper is to compare the adverse effects, and to describe the effects on indirect markers of renal function of long-term creatine supplementation. 175 subjects (age = 57.7 +/- 11.1 y) were randomly assigned to receive creatine monohydrate 10 g daily or placebo during an average period of 310 days. After one month, two months and from then on every fourth month, adverse effects were scored using dichotomous questionnaires, plasma urea concentrations were measured, and urinary creatine and albumin concentrations were determined. No significant differences in the occurrence at any time of adverse effects due to creatine supplementation were found (23 % nausea in the creatine group, vs. 24 % in the placebo group, 19 % gastro-intestinal discomfort in the creatine group, vs. 18 % in the placebo group, 35 % diarrhoea in the creatine group, vs. 24 % in the placebo group). After two months of treatment, oedematous limbs were seen more often in subjects using creatine, probably due to water retention. Severe diarrhoea (n = 2) and severe nausea (n = 1) caused 3 subjects in the creatine group to stop intake of creatine, after which these adverse effects subsided. Long-term supplementation of creatine did not lead to an increase of plasma urea levels (5.69 +/- 1.47 before treatment vs. 5.26 +/- 1.44 at the end of treatment) or to a higher prevalence of micro-albuminuria (5.4 % before treatment vs. 1.8 % at the end of treatment).

http://www.ncbi.nlm.nih.gov/pubmed/15795816

suplementacja kreatyna przez okres 310 dni nie miala zadnego lub tez wiekszego wplywu na zdrowie osob w porownaniu do grupy placebo


Creatine: a review of efficacy and safety.

Despite the many clinical trials, high-quality research is lacking. Laboratory investigations of endurance isotonic exercises, strength and endurance during isotonic exercises, isokinetic torque, isometric force, and ergometer performance have yielded roughly an equal number of published studies showing a positive effect or lack of effect. Field studies (i.e., on subjects participating in sports activities) are less impressive than laboratory studies. Performance was more often improved for short-duration, high-intensity activities. Reports have linked creatine to weight gain, cramping, dehydration, diarrhea, and dizziness. Creatine may decrease renal function, but only two case reports of this effect have been published. Creatine appears to be well tolerated in short-term trials.

http://www.ncbi.nlm.nih.gov/pubmed/10609446

wedlug niektorych zrodel kreatyna moze pogarszac prace nerek - ale tylko dwa badania wskazuja na takie dzialanie (znajac zycie badano wplyw kretyny na ludzi z uszkodzana fukncja nerek)
suma sumarum - kreatyna wydaje sie byc dobrze tolerowana substancja w w krotkich cyklach!


Is the use of oral creatine supplementation safe?

This review focuses on the potential side effects caused by oral creatine supplementation on gastrointestinal, cardiovascular, musculoskeletal, renal and liver functions. No strong evidence linking creatine supplementation to deterioration of these functions has been found. In fact, most reports on side effects, such as muscle cramping, gastrointestinal symptoms, changes in renal and hepatic laboratory values, remain anecdotal because the case studies do not represent well-controlled trials, so no causal relationship between creatine supplementation and these side-effects has yet been established. The only documented side effect is an increase in body mass. Furthermore, a possibly unexpected outcome related to creatine monohydrate ingestion is the amount of contaminants present that may be generated during the industrial production. Recently, controlled studies made to integrate the existing knowledge based on anecdotal reports on the side effects of creatine have indicated that, in healthy subjects, oral supplementation with creatine, even with long-term dosage, may be considered an effective and safe ergogenic aid. However, athletes should be educated as to proper dosing or to take creatine under medical supervision.

http://www.ncbi.nlm.nih.gov/pubmed/15758854

kreatyne posadza sie o powodowanie roznych skutkow ubocznych - jak od problemow z ukladem pokarmowym,uszkodzenia watroby czy inne - tak do tej pory nie znaleziono ewidentnych wnioskow aby kreatyna powodowala takie skutki!


Side effects of creatine supplementation in athletes.

CONTEXT: Allegations about side effects of creatine supplementation by athletes have been published in the popular media and scientific publications.

PURPOSE: To examine the experimental evidence relating to the physiological effects of creatine supplementation.

RESULTS: One of the purported effects of oral creatine supplementation is increased muscle mass. A review of the literature reveals a 1.0% to 2.3% increase in body mass, which is attributed to fat-free mass and, more specifically, to skeletal-muscle mass. Although it is unlikely that water retention can completely explain these changes, increase in muscle-protein synthesis has never been observed after creatine supplementation. Indirect evidence based on mRNA analyses suggests that transcription of certain genes is enhanced. Although the effect of creatine on muscle-protein synthesis seems irrefutable according to advertising, this allegation remains under debate in the scientific literature. The kidneys appear to maintain their functionality in healthy subjects who supplement with creatine, even over several months.

CONCLUSION: The authors, however, think that creatine supplementation should not be used by an individual with preexisting renal disease and that risk should be evaluated before and during any supplementation period. Even if there is a slight increase in mutagenic agents (methylamine and formaldehyde) in urine after a heavy load of creatine (20 g/day), their excretion remains within a normal range. No data are currently available regarding the potential production of heterocyclic amines with creatine supplementation. In summary, the major risk for health is probably associated with the purity of commercially available creatine.

http://www.ncbi.nlm.nih.gov/pubmed/19124889

wedlug badan kreatyna powoduje wzrost beztluszczowej masy ciala srednio o 1-2,3%
co nie stanowi tluszcz - tylko beztluszczowa masa miesniowa!
retencja wody nie moze wyjasnic czy byc odpowiedzialna za te zmiany - ale nigdy nie badano wplywu kreatyny na synteze bialka

jesli chodzi o nerki - krotkie cykle nie maja zadnego wplywu na jej dzialanie!
w czasie cykli kiedy spozywane sa olbrzymie ilosci kreatyny (20g/dzien)
fakt - wzrosta ilosc mutagenow - ale wszystko dalej miesci sie w granicach norm!

najwazniejsze - negatywny wplyw (jesli juz) kreatyny na nasze zdrowie w najwiekszym stopniu jest powiazany z czystoscia kreatyny jaka spozywamy!



tu ciekawe badanie/wnioski z badan:

Is there a rationale for the use of creatine either as nutritional supplementation or drug administration in humans participating in a sport?

Even though no unambiguous proof for enhanced performance during high-intensity exercise has yet been reported, the creatine administration is charged to improve physical performance and has become a popular practice among subjects participating in different sports. Appropriate creatine dosage may be also used as a medicinal product since, in accordance with the Council Directive 65/65/CEE, any substance which may be administered with a view to restoring, correcting or modifying physiological functions in human beings is considered a medicinal product. Thus, quality, efficacy and safety must characterize the substance. In biochemical terms, creatine administration enhances both creatine and phosphocreatine concentrations, allowing for an increased total creatine pool in skeletal muscle. In thermodynamics terms, creatine interferes with the creatine-creatine kinase-phosphocreatine circuit, which is related to the mitochondrial function as a highly organized system for the energy control of the subcellular adenylate pool. In pharmacokinetics terms, creatine entry into skeletal muscle is initially dependent on the extracellular concentration, but the creatine transport is subsequently down-regulated. In pharmacodynamics terms, the creatine enhances the possibility to maintain power output during brief periods of high-intensity exercises. In spite of uncontrolled daily dosage and long-term administration, no research on creatine safety in humans has been set up by specific standard protocol of clinical pharmacology and toxicology, as currently occurs in phase I for the products for human use. More or less documented side effects induced by creatine are weight gain; influence on insulin production; feedback inhibition of endogenous creatine synthesis; long-term damages on renal function. A major point that related to the quality of creatine products is the amount of creatine ingested in relation to the amount of contaminants present. During the production of creatine from sarcosine and cyanamide, variable amounts of contaminants (dicyandiamide, dihydrotriazines, creatinine, ions) are generated and, thus, their tolerable concentrations (ppm) must be defined by specific toxicological researches. Creatine, as the nutritional factors, can be used either at supplementary or therapeutic levels as a function of the dose. Supplementary doses of nutritional factors usually are of the order of the daily turnover, while therapeutic ones are three or more times higher. In a subject with a body weight of 70 kg with a total creatine pool of 120 g, the daily turnover is approximately 2 g. Thus, in healthy subjects nourished with a fat-rich, carbohydrate-, protein-poor diet and participating in a daily recreational sport, the oral creatine supplementation should be on the order of the daily turnover, i.e. less than 2.5-3 g per day, bringing the gastrointestinal absorption to account. In healthy athletes submitted daily to high-intensity strength- or sprint-training, the maximal oral creatine supplementation should be on the order of two times the daily turnover, i.e. less than 5-6 g per day for less than 2 weeks, and the creatine supplementation should be taken under appropriate medical supervision. The oral administration of more than 6 g per day of creatine should be considered as a therapeutic intervention because the dosage is more than three times higher than the creatine daily turnover and more than six times higher than the creatine daily allowance. In this case, creatine administration should be prescribed by physicians only in the cases of suspected or proven deficiency, or in conditions of severe stress and/or injury

http://www.ncbi.nlm.nih.gov/pubmed/10675277

kreatyna zwieksza poziom kreatyny i fosfokreatyny zwiekszajac tym samym calkowita pule kreatyny w organizmie
co powoduje wzrost poziomu energi co znowu skutkuje wieksza moca
innym kolejnym 'skutkiem ubocznym' jest wzrost wagi ciala

skutkiem ubocznym jest to ze powstawaniu kreatyny towarzyszy wzrost poziomu toxyn jak rowniez wzrost poziomu kreatyniny

calkowita pula kreatyny u zdrowego czlowieka wynosi ok 120g
dzienna produkcja kreatyniny wynosi ok 2g
wnioski takie - aby zachowac staly poziom kreatyny nalezy spozywac mniej wiecej tyle samo ile ulega przemianie do kreatyniny - mniej niz 3g
jezeli brac pod uwage sportowcow to dzienna dawka kreatyny powinna byc dwa razy wieksza niz jej straty - co daje 5-6g/dzien!
stad ta magiczna dawka 5g/dzien

uzywanie wiekszych dawek powinno sie konsultowac z lekarzem



na koniec stare badanie - z 1996 roku - kiedy to stosowano fazy nasycenia lub tez nie

Muscle creatine loading in men.

The effect of dietary creatine and supplementation on skeletal muscle creatine accumulation and subsequent degradation and on urinary creatinine excretion was investigated in 31 male subjects who ingested creatine in different quantities over varying time periods. Muscle total creatine concentration increased by approximately 20% after 6 days of creatine supplementation at a rate of 20 g/day. This elevated concentration was maintained when supplementation was continued at a rate of 2 g/day for a further 30 days. In the absence of 2 g/day supplementation, total creatine concentration gradually declined, such that 30 days after the cessation of supplementation the concentration was no different from the presupplementation value. During this period, urinary creatinine excretion was correspondingly increased. A similar, but more gradual, 20% increase in muscle total creatine concentration was observed over a period of 28 days when supplementation was undertaken at a rate of 3 g/day. In conclusion, a rapid way to "creatine load" human skeletal muscle is to ingest 20 g of creatine for 6 days. This elevated tissue concentration can then be maintained by ingestion of 2 g/day thereafter. The ingestion of 3 g creatine/day is in the long term likely to be as effective at raising tissue levels as this higher dose.

http://www.ncbi.nlm.nih.gov/pubmed/8828669

suplemenatcja kreatyna w ilosci 20g/dzien przez okres 6 dni zwiekszyla poziom kreatyny o ponad 20%
od 7 dnia stosowano dawke 2g/dzien przez kolejne 30dni
poziom kreatyny pozostal na tym samym poziomie (+20%)

druga grupa spozywala 3g/dzien (wiecej niz przemienia sie a kreatynine) - stopniowy wzrost calkowitej puli w organizmie na koncu i tak wynosil 20%!

tak wiec czy stosuje sie faze nasycania (5-6 dni x 20g) czy tez nie (stala suplementacja 3g/dzien) - skutkowac bedzie takim samym poziomem kreatyny
z tym ze stosujac dawke 20g ten 'szczyt' osiagnie sie szybciej

a kto jaka metoda wybierze zalezy juz tylko od niego
obie sa dobre!

Juz jakis czas temu naczytalem sie roznych badan o mono i zadne z nich nie stwierdzilo wyzszosci stosowania faz nasycenia, co wiecej STANDARDOWEGO ladowania 2x5 w DT i 1x5 w DNT /7,5g w cyklu dwudniowym/. Okazalo sie, ze dawka wystarczajaca to bodajze 0,03g/kgmc, czyli dla 100kg faceta dawka odpowiednia do zachowania zwiekszonego poziomu kretki w organizmie to 3g!.

Czytalem rowniez badanie mowiace o stalej suplementacji kreatyna w nieco mniejszej dawce, zapewniajace rowniez podwyzszony jej poziom. Niestety nie posiadam w tej chwili zadnych badan/linkow do artow.

/pozdr

wyzej masz wszystko rozpisane - dlaczego takie dawki a nie inne
tak samo brak wyzszosci jednego typu dawkowania nad innym

Ale ja to wiem przeciez

/pozdr