Srednio u osobnika 70kilowego znajduje sie ok 120g kreatyny.
Ok.95% znajduje sie w miesniach szkieletowych.
Z czego ok 65% pod postacia fosfokreatyny - reszte stanowi kreatyna.
W ciagu dnia w miesniach nastepuje przemiana ok 1-2% do kreatyniny.
Wplyw kreatyny zostal (m.in.)przedstawiony w tych tematach:
https://www.sfd.pl/Kreatyna__wzrost_wytrzymałosci,siły_i_masy_miesniowej-t695548.html
https://www.sfd.pl/Kreatyna__długotrwałe_stosowanie_a_skutki_uboczne.-t704443.html
https://www.sfd.pl/Kreatyna__Czas_wypłukania_jak_dlugi_czas_przerwy_-t703114.html
https://www.sfd.pl/Kreatyna__monohydrat_kreatyny_vs._różne_formy_kreatyny_-t704503.html
Pora zając sie kwestią - ludzi którzy lepiej odczuwają działanie kreatyny lub takich którzy mniej lub nawet wcale.
Wedlug badań ok 70-80% ludzi stosujących kreatyne odczuwa jej działania.
Z czego ~20% osiąga maxymalne wyniki.
Ale jest tez pozostala grupa 20-30% ktorzy nie odczuwaja działania kreatyny wogole lub znikomo!
Powodow moze byc kilka:
-osoby ktorzy bardziej odczuwaja działanie kreatyny maja mniejsze zasoby 'wlasnej' kreatyny,tym samym sa w stanie zmagazynowac wieksze ilośći kreatyny dostarczanej w formie suplementów
-osoby ktore maja wiekszą ilość włokień mieśniowych typu II(szybkokurczliwe),gdzy zostalo udowodnione ze wieksza ilość kreatyny znajduje sie we wlonach tego ypu niz typu I(wolnokurczliwe)
-czy tez posiadają wiekszą masę mieśniową czy też tluszczową
Effect of oral creatine supplementation on skeletal muscle phosphocreatine resynthesis
Biopsy samples were obtained from the vastus lateralis muscle of eight subjects after 0, 20, 60, and 120 s of recovery from intense electrically evoked isometric contraction. Later (10 days), the same procedures were performed using the other leg, but subjects ingested 20 g creatine (Cr)/day for the preceding 5 days. Muscle ATP, phosphocreatine (PCr), free Cr, and lactate concentrations were measured, and total Cr was calculated as the sum of PCr and free Cr concentrations. In five of the eight subjects, Cr ingestion substantially increased muscle total Cr concentration (mean 29 +/- 3 mmol/kg dry matter, 25 +/- 3%; range 19-35 mmol/kg dry matter, 15-32%) and PCr resynthesis during recovery (mean 19 +/- 4 mmol/kg dry matter, 35 +/- 6%; range 11-28 mmol/kg dry matter, 23-53%). In the remaining three subjects, Cr ingestion had little effect on muscle total Cr concentration, producing increases of 8-9 mmol/kg dry matter (5-7%), and did not increase PCr resynthesis. The data suggest that a dietary-induced increase in muscle total Cr concentration can increase PCr resynthesis during the 2nd min of recovery from intense contraction.
http://ajpendo.physiology.org/content/266/5/E725.abstract
8 uczestnikow dostawalo 20g kreatyny przez okres 5dni
wyniki:
u 5 z 8 uczestnikow zawartosc calkowitej kretyny wzrosla od 15-32%!
u pozostalych 3 osob ten wzrost wynosil 5-7%
.....tylko
Acute creatine monohydrate supplementation: a descriptive physiological profile of responders vs. nonresponders.
The purpose of this study was to describe the physiological profile of responders (>20 mmol.kg(-1) dry weight [dw] increase in total intramuscular creatine monohydrate [Cr] + phosphorylated creatine [PCr]) versus nonresponders (<10 mmol.kg(-1) dw increase) to a 5-day Cr load (0.3 g.kg(-1).d(-1)) in 11 healthy men (mean age = 22.7 years). Pre-post 5-day cellular measures included total resting Cr content (Cr + PCr), fiber type composition, and fiber type cross-sectional area (CSA) determined from muscle biopsies of the vastus lateralis. Body mass, daily dietary intake, 24-hour urine outputs, urinary Cr and creatinine (CrN), and strength performance measures (1 repetition maximum [1RM] bench and leg press) were also assessed before and after the 5-day loading period. Results indicated that there were 3 levels of response to the 5-day supplementation: responders (R), quasi responders (QR), and nonresponders (NR) with mean changes in resting Cr + PCr of 29.5 mmol.kg(-1) dw (n = 3), 14.9 mmol.kg(-1) dw (n = 5), and 5.1 mmol.kg(-1) dw (n = 3), respectively. The results support a person-by-treatment interaction to acute Cr supplementation with R possessing a biological profile of lowest initial levels of Cr + PCr, greatest percentage of type II fibers, and greatest preload muscle fiber CSA and fat-free mass. Responders also showed improvement in 1RM leg press scores following the 5-day loading period. NR had higher preload levels of Cr + PCr, less type II muscle fibers, small preload muscle CSA, and lower fat-free mass and displayed no improvements in 1RM strength scores. The results suggest that to be considered a responder to acute oral supplementation, a favorable preexisting biological profile may determine the final extent to which an individual responds to supplementation. Physiologic profiles of nonresponders appear to be different and may limit their ability to uptake Cr. This may help partially explain the reported equivocal performance findings in the Cr supplementation literature.
http://www.ncbi.nlm.nih.gov/pubmed/15320650
11 mezczyzn spozywalo przez 5 dni kretyne w ilosci 0,3g/kgmc/dzien (100kg=30g kretyny/dzien)
wyniki:
po analizie wynikow badan zauwazono 3 grupy:
-osoby u ktorych bardzo wzrosl poziom calkowitej kreatyny
-osoby ze srednim wzrostem
-osoby z bardzo malym wzrostem
zauwazno nastepujace zmaiany w poziomie kreatyny:
>20mmol/kg -> grupa dobrze reagujaca
10-20mmol/kg -> grupa srednio reagujaca
<10mmol/kg ->grupa slabo regująca
z czego wynikaja roznice?
-z roznego poziomu kreatyny przed rozpoczesciem stosowania suplemntów z kreatyna
-rozne ilosci włokien
-mniejsza ilośc wlokien typu II
-mniejsza masa tluszczowa/miesniowa
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=415af131eb32ad33f90f4fdeb2d56835c871fc73&keytype2=tf_ipsecsha
badanie wykazuje zaleznosc:
poprawa wykonania treningu i ilosc wykonanej pracy jest wieksza,jesli jest wieksza zawartosc fosfokreatyny we wloknach typu II
Effects of creatine supplementation on performance and training adaptations.
Creatine has become a popular nutritional supplement among athletes. Recent research has also suggested that there may be a number of potential therapeutic uses of creatine. This paper reviews the available research that has examined the potential ergogenic value of creatine supplementation on exercise performance and training adaptations. Review of the literature indicates that over 500 research studies have evaluated the effects of creatine supplementation on muscle physiology and/or exercise capacity in healthy, trained, and various diseased populations. Short-term creatine supplementation (e.g. 20 g/day for 5-7 days) has typically been reported to increase total creatine content by 10-30% and phosphocreatine stores by 10-40%. Of the approximately 300 studies that have evaluated the potential ergogenic value of creatine supplementation, about 70% of these studies report statistically significant results while remaining studies generally report non-significant gains in performance. No study reports a statistically significant ergolytic effect. For example, short-term creatine supplementation has been reported to improve maximal power/strength (5-15%), work performed during sets of maximal effort muscle contractions (5-15%), single-effort sprint performance (1-5%), and work performed during repetitive sprint performance (5-15%). Moreover, creatine supplementation during training has been reported to promote significantly greater gains in strength, fat free mass, and performance primarily of high intensity exercise tasks. Although not all studies report significant results, the preponderance of scientific evidence indicates that creatine supplementation appears to be a generally effective nutritional ergogenic aid for a variety of exercise tasks in a number of athletic and clinical populations.
http://www.ncbi.nlm.nih.gov/pubmed/12701815
po analizie ok.300 badan wyciagnieto wnioski ze kretyna wykazuje pozytywne działanie u okolo 70% tych badan
"Cóż jest trucizną?
Wszystko jest trucizną i nic nie jest trucizną, tylko dawka czyni, że dana substancja nie jest trucizną!".
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