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The effect of creatine monohydrate ingestion on anaerobic power indices, muscular strength and body composition

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Acta Physiol
The effect
creatine monohydrate ingestion on
anaerobic power indices, muscular strength and
‘Texas Woman’s University, Department
Texas Southwestern Medical Center and 3The Cooper Clinic, Dallas, Texas,
Creatine monohydrate (Cr.H20) has been shown to
increase intramuscular phosphocreatine (Harris et
1992) as well as increasing the power output of various
high intensity work tasks (Balsom et
1993). To the author’s knowledge,
Cr.H20 supplementation in strength trained athletes
has not yet been reported in the literature. Therefore,
this study investigated the influence of Cr.H20
supplementation on muscular power and strength
indices in
experienced weight-trained male subjects.
Three series of high intensity, anaerobic type,
muscular workbouts were used. Series one included
three consecutive 30-s Wingate bike tests, interspersed
with 5 min of rest. Peak anaerobic power was denoted
as the greatest power achieved in a given 5-s work
interval. Anaerobic work was defined as the total
amount of work performed in a 30-s period. Series
two utilized
one repetition maximum (1 RM) free
weight bench press as a test of muscular strength.
Series three employed complete lifting repetitions at
70% of the bench press
RM until fatigue. Lifting
cadence was paced through the use of a metronome set
at a 1-s timing interval (1
eccentric, 1
and fatigue was defined as (1) the inability to complete
one lifting repetition or (2) the inability to maintain
the lifting cadence. Total lifting volume was calculated
as 70% of pre-test 1 RM multiplied by the number of
complete lifting repetitions. Body composition was
measured via hydrostatic weighing techniques; a 3-
day recall was used to assess dietary differences
between groups.
procedures were approved by the
Human Subjects Review Board of Texas Woman’s
University, Denton, Texas.
Received 19 September 1994, accepted 13 October
anaerobic power, body composition,
Earnest, 7855 Willow
creatine, muscular strength.
Hill Court
Ste. 233, Dallas, TX 75230, USA.
Subjects received, in
double blind fashion, either
a glucose placebo or Cr.H20 supplement (Phosphagen,
Experimental and Applied Sciences Inc., Pacific
Grove, CA, USA) as has previously been shown to be
successful (Harris et
1992, Greenhaff
After 14 days of supplementation, each subject was re-
the Wingate bike tests. Re-testing for the
weight lifting and anthropometric parameters took
place after 28 days of supplementation. An
repeated measures was utilized
assess differences
within the Wingate test groups. If statistical signifi-
cance was found,
Newman-Keuls post-hoc analysis
was applied.
paired dependent t-test was used to
determine differences associated with bench press
total lifting volume and anthropometric
measures. An independent t-test was used to de-
termine differences in nutritional/energy intake.
Statistical significance was set at
0.05. All values
are listed as pre- vs. post-test and mean
Eight subjects completed the experimental protocol.
Age was 29.5
3.6 and 31.8
2.2 years, training
experience was 10.8f3.2 and 11.1 f2.4 years and
percentage of body fat was 10.1
3.7 and 9.4f4.6 for
the Cr.H20 and placebo groups, respectively. Within
the Cr.H20 group
4), total anaerobic work for
the Wingate tests was significantly higher during all
post-test trials (P
0.05). These increases were 13%
for Wingate test 1,
for Wingate test 2 and 18%
for Wingate test 3.
changes were noted in the
placebo group
4, Table
Greater total an-
aerobic work resulted from the Cr.H20 subject’s
ability to achieve and maintain higher levels of
anaerobic power consistently over each
interval, with statistical significance being apparent
for several 5-s power intervals during the three trials
(data not shown).
Bench press 1 RM increased 6% in the Cr.H20
group (P
0.05). When corrected for body weight no
differences were noted because of a significant increase
in body weight within the Cr.H20 group. Total lifting
Anaerobic indices values for Cr.H20 and placebo groups. Values are mean and SD
0.01, and
~ ~~ ~~ ~~~~ ~~~ ~
Creatine Placebo
Anaerobic indices Pre Post Pre Post
30-s Wingate bike tests
1 (kJ)
3 (kJ)
Bench press 1 RM
Absolute (kg)
Relative (kg kg-')
Lifting repetitions (70% 1
Total lifting volume
Absolute (kg)
Relative (kg kg-')
22.65 (3.0)
20.40 (2.0)
18.54 (1.0)
11.5 (0.8)
1017.7 (93.5)
11.7 (0.7)
25.98 (4.0)*
24.49 (3.0)*
134.6 (18.9)*
1.5 (0.1)
1459.0 (122.3)f
16.5 (0.9)f
23.48 (1.0)
21.15 (2.0)
119.1 (13.0)
11.7 (1.8)
975.1 (120.9)
11.8 (1.2)
22.08 (2.0) 23.51 (1.0)
22.32 (2.0)
21.4 (2.0)
116.2 (15.0)
1.4 (0.1)
951.7 (132.0)
11.5 (1.5)
volume was significantly higher within the Cr.H20
group, whether expressed in absolute terms (26%,
0.01) or relative terms (29%,
0.001). In-
creases in total lifting volume were associated with the
the Cr.H20 group to perform 26% more
lifting repetitions
0.01, Table 1). Body com-
position data indicated a significant increase in body
weight (86.5+ 13.7 vs. 88.2+ 14.1 kg,
well as
non-significant increase
calculated fat free
mass (77.6
10.8 vs. 79.2
11.6 kg,
0.054) for
the Cr.H20 group.
changes in body weight
(82.6f 2.2 vs. 82.5 1.8 kg) or fat free mass (74.9
vs. 74.4 6.2 kg) were noted for the placebo group. In
addition, no significant differences were noted for
percentage of body fat in either group. These
observations were noted in spite of a significantly
lower daily energy intake (10031 1458 vs.
14650+ 1234 kJ;
0.01), carbohydrate intake
(5918f860 vs. 7315+617
and fat
intake (1204+175 vs. 4354+368 kJ;
0.05) for
the Cr.H+l vs. placebo groups, respectively.
The observed higher work outputs in the Cr.H20
group were consistent with increases in intramuscular
phosphocreatine stores as noted previously (Harris
1992), increased ATP cycling through an attenuated
reduction in ATP with repeated work tasks (Greenhaff
1994 b), and an increased rate of phosphocreatine
resynthesis during recovery periods (Greenhaff
1994a). What is not clear is the associated gain in body
weight observed in our study as well as those of others
1993, Greenhaff
1994a). We are
the first group to show that: (1) Cr.H20 supplemen-
tation improves strength training parameters and (2)
that the associated weight gain may be related to an
increase in fat free mass as determined through
hydrostatic weighing techniques.
addition, because
weight lifting tasks are typically performed
maximal 1 RM levels during training, the ability
the Cr.H20 group to perform a greater total lifting
volume, both in absolute and relative terms, demon-
strates the efficacy of Cr.H20 as an ergogenic aid.
turn, the ability
perform greater muscular work,
per given work task, provides
greater muscular
overload that may promote an increased adaptive
muscular structure and function.
adaptation may account for the observed increase
bench press 1 RM, body weight and fat free mass.
Whether or not Cr.H20
is directly responsible
for this increase in body weight has yet to be
We thank Christopher B. Scott
the Dallas Heart
Group for his help in the preparation of this
manuscript. This study was supported by
from Experimental and Applied Sciences, Inc. Pacific
Grove, CA, USA.
1993. Creatine supplementation
and dynamic high intensity intermittent exercise.
1993. Influence
of oral creatine supplementation of muscle torque
during repeated bouts
maximal voluntary lifting
exercise in man.
HULTMAN. 1994a. Effect of oral creatine sup-
Creatine supplementation and anaerobic indices
degradation during repeated bouts
voluntary exercise in man.
E. 1992.
creatine in resting and exercised muscle
normal subjects by creatine supplementation.
plementation on skeletal muscle phosphocreatine
(Endocrinol Met 29),
E. 1994b. The effect
creatine supplementation on skeletal muscle ATP
... The most common ingredients are amino acids, proteins, creatine and caffeine (LaBotz & Griesemer, 2009). There is a large number of studies observing the influence of supplementation to physical abilities (El Khoury & Antoine, 2012;Morrison, Gizis, & Shorter, 2004;Rocha & Pereira, 1998;Pereira, Jajolo, & Hirschbruch, 2003;Gomes, Degiovanni, Garlipp, & Chiarello, 2008;Goston & Correlia, 2010;Oliver, Leon, & Hernandez, 2008) amnd changes of body composition (Earnest et al., 1995;Kreider, Ferreira, et al., 1998;Kreider, Klesges, et al., 1996;Vandenberghe et al., 1997). CR is also a part of diet and is mostly found in meat and fish and when consumed 98% is deposited in the muscles and the remaining part in the brain, heart and other organs, while the excess is processed by kidneys and excreted in the form of creatinine (Cannan & Shore, 1928). ...
... Many studies which dealt with the effects of CR confirmed that the body weight increases after a period of oral ingestion (Fairman, Kendall, Hart, Taaffe, Galvao, & Newton, 2019;Vilar-Neto, et al., 2018;Earnest, Snell, Rodriguez, Almada, & Mitchell, 1995;Hultman, Sijderlund, Timmons, Cederblad, & Greenhaff, 1996;Kreider, Ferreira, & Wilson, 1998). Previous studies confirm that 10-20g of CR at daily level with the frequency of five days a week is sufficient for increase in strength and number of repetitions (Urbanski, Loy, Vincent, & Yaspelkis, 1999;Izquierdo, Ibañez, & González-Badillo, 2002). ...
... Muscle mass, as an integral part of overall mass is significantly increased with CR supplementation. In some papers it was noted that there is also increase in total mass in range 0.7-1.6 kg after short-term CR intake in combination with exercises with load (Becque, Lochmann, Melrose, 2000;Earnest, Snell, Rodriguez, Almada, & Mitchell, 1995;Vandenberghe, Van-Hecke, Leemputte, Vanstapel, & Hespel, 1999). LaBotz & Griesemer (2009) established significant increase of body mass of 0.84 kg in CR group, in relation to the control group. ...
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Kreatin je postao popularan dodatak prehrani među sportistima. Najnovija istraživanja takođe s sugerišu da postoji veliki broj potencijalnih terapijskih primjena kreatina. Cilj ovog sistematskog pregleda je da se ispitaju efekti CR na mišićnu snagu i tjelesnu kompoziciju, na temelju prikupljenih podataka i analiziranih radova objavljenih u periodu 2018.-2020 godine. Pretraživanje literature izvršeno je pomoću sledećih baza: PubMed, Scholar Google, DOAJ. Radovi su odabrani na osnovu više kriterijuma. Rezultati ukazuju da CR u kombinaciji sa nekim programom vježbanja rezultira povećanjem mišićne mase, povećava snagu, smanjuje vrijeme izvođenja određene aktivnosti. Promjene u tjelesnoj kompoziciji ogledaju se u povećanju ukupne mase i mišićne mase kao i količine vode u sastavu tijela. Korišćenje CR u omjeru 10-20gr na dnevnom nivou i učestalosti korišćenja od 4-5 dana nedeljno, predstavlja efikasno sredstvo za poboljšanje sportskih performansi i pozitivnih promjena u sastavu tijela.
... Previous studies have demonstrated that the muscle store of total creatine (PCr + creatine) can increase by about 10-20% after oral creatine supplementation [13]. Creatine supplementation was shown to increase performance during high intensity exercise in some studies [14][15][16] but not in others [17,18]. ...
... Post -exercise hypoxanthine [16] and plasma NH3 [15] were reduced following creatine supplementation even though there was an increase in work performed. These findings support the hypothesis that limitations to energy supply are a major cause of fatigue during high intensity exercise. ...
The purpose of the paper is to consider the metabolic mechanisms contributing to high intensity exercise performance, recovery, and fatigue. A further purpose is also to consider the total stress response to exercise by outlining the catecholamine responses to exercise performance
... Furthermore, although in Set 3 there was no statistical significance, the CR group performed 12.7% more repetitions. These results are in line with those of previous studies, which consistently report that CR supplementation increases the capacity to recover between peaks of intermittent activity during different types of exercise, such as repeated Wingate efforts [26,47], rowing sprints [48], cycling sprints [14,24,25,49], running sprints [28][29][30][31], swimming sprints [32], resistance exercise [33,34,47], and maximal voluntary isokinetic contractions [15]. This could be due to the increase in the content of intramuscular PCr produced by the CR supplementation, since increases of 10-40% in the content of PCr have been previously reported [6], as well as increases in the amount of PCr re-synthesis during the different recovery periods [50]. ...
... Furthermore, although in Set 3 there was no statistical significance, the CR group performed 12.7% more repetitions. These results are in line with those of previous studies, which consistently report that CR supplementation increases the capacity to recover between peaks of intermittent activity during different types of exercise, such as repeated Wingate efforts [26,47], rowing sprints [48], cycling sprints [14,24,25,49], running sprints [28][29][30][31], swimming sprints [32], resistance exercise [33,34,47], and maximal voluntary isokinetic contractions [15]. This could be due to the increase in the content of intramuscular PCr produced by the CR supplementation, since increases of 10-40% in the content of PCr have been previously reported [6], as well as increases in the amount of PCr re-synthesis during the different recovery periods [50]. ...
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Background: The aims of this study were to analyse the effect of creatine supplementation on the performance improvement in a bench pressing (BP) strength test of muscle failure and to evaluate muscle fatigue and metabolic stress 20 min after the exercise. Methods: Fifty young and healthy individuals were randomly assigned to a creatine group (n = 25) or a placebo group (n = 25). Three exercise sessions were carried out, with one week of rest between them. In the first week, a progressive load BP test was performed until the individuals reached the one repetition maximum (1RM) in order to for us obtain the load-to-velocity ratio of each participant. In the second week, the participants conducted a three-set BP exercise protocol against 70% 1RM, where they performed the maximum number of repetitions (MNR) until muscle failure occurred, with two minutes of rest between the sets. After one week, and following a supplementation period of 7 days, where half of the participants consumed 0.3 g·kg-1·day-1 of creatine monohydrate (CR) and the other half consumed 0.3 g·kg-1·day-1 of placebo (PLA, maltodextrin), the protocol from the second week was repeated. After each set, and up to 20 min after finishing the exercise, the blood lactate concentrations and mean propulsive velocity (MPV) at 1 m·s-1 were measured. Results: The CR group performed a significantly higher number of repetitions in Set 1 (CR = 14.8 repetitions, PLA = 13.6 repetitions, p = 0.006) and Set 2 (CR = 8 repetitions, PLA = 6.7 repetitions, p = 0.006) after supplementation, whereas no significant differences were seen in Set 3 (CR = 5.3 repetitions, PLA = 4.7 repetitions, p = 0.176). However, there was a significant increase in blood lactate at minute 10 (p = 0.003), minute 15 (p = 0.020), and minute 20 (p = 0.015) after the exercise in the post-supplementation period. Similarly, a significant increase was observed in the MPV at 1 m·s-1 in the CR group with respect to the PLA group at 10, 15, and 20 min after the exercise. Conclusions: Although the creatine supplementation improved the performance in the strength test of muscle failure, the metabolic stress and muscle fatigue values were greater during the 20 min of recovery.
... Earnest al. [56] carried out a study on experienced strength athletes, in which following 14 days of creatine supplementation (not specifying the amount), they obtained a significant improvement in power levels in the WAT. Casey et al. [57] also recorded improvements in the work performed (peak and total) during a maximum isokinetic test following supply of a 20 g supplement of creatine per day over five days. ...
Full-text available
The Wingate Anaerobic Test (WAT) has been widely used since its creation in 1974. The WAT involves performing a 30 s “all-out” cycling test. The test is currently applied with some modifications, partly due to the evolution of the material used to perform it. The purpose of this text is to act as a guide for the correct use and application of the test, as well as to highlight the importance of controlling many of the variables that may influence its results. Methods: A literature search was conducted in PUBMED/MEDLINE and Web of Science with different combinations of keywords all related to the WAT to obtain a search of 113 papers. Results and discussion: It was observed that variables such as the duration of the test or the resistance used in the cycle ergometer must be adjusted according to the objective and the population evaluated, while others such as the warm-up or the supplementation of different substances can improve performance on the WAT. Conclusions: In order to apply the WAT correctly, variables such as duration, resistance used or warm-up time and intensity must be adjusted according to the evaluated subjects and the aim of the study. Other variables such as position on the bike or equipment used should also be controlled if we want to guarantee its replicability.
... Several studies have shown that creatinine loading increases muscle strength and performance during maximum strength training or repetitive exercises depending on the preload state [5]. For this reason, weightlifters, runners, and swimmers benefit from oral creatinine supplementation [6]. ...
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In this study, a new amperometric biosensor for creatinine determination was developed. For this purpose, a polypyrrole-polyvinylsulfonate film was prepared by electropolymerization of pyrrole in a polyvinylsulfonate medium on a platinum plate. Creatinase and sarcosine oxidase enzymes were immobilized on polypyrrole-polyvinylsulfonate film by cross-linking with glutaraldehyde. The determination of creatinine was made based on the oxidation of hydrogen peroxide at 0.4 V formed as a result of the enzymatic reaction on the surface of the prepared biosensor. The linear working range of the biosensor obtained was found between 5.0 ×\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document} 10⁻⁶ and 1.0 ×\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document} 10⁻⁴ M. Using this linear graph, the Km (observed) and Imax (observed) values for the double enzyme electrode system were calculated as 5.0 ×\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document} 10⁻³ mM and 0.34 µA/min, respectively. Optimum working pH and temperature were determined as 8.0 and 60 °C, respectively. The reusability and shelf life of the biosensor were determined. The effects of interferences in biological environments on biosensor response were investigated. For this purpose, uric acid, ascorbic acid, paracetamol, glycine, urea, and formaldehyde were used. The results have shown that the prepared biosensor has the potential to be used for creatinine determination in biological fluids. Graphical abstract
... Weight gain is the only side effect that has been suggested which may be a desirable effect for many patients and athletes (Earnest et al., 1995;Juhn, 1999;Kutz & Gunter, 2003). In contrast to this safety, worries have been increased in the scientific community and The present meta-analysis had several limitations, including: ...
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Exercise-induced muscle damage (EIMD) causes increased soreness, impaired function of muscles, and reductions in muscle force. Accumulating evidence suggests the beneficial effects of creatine on EIMD. Nevertheless, outcomes differ substantially across various articles. The main aim of this meta-analysis was to evaluate the effect of creatine on recovery following EIMD. Medline, Embase, Cochrane Library, Scopus, and Google Scholar were systematically searched up to March 2021. The Cochrane Collaboration tool for examining the risk of bias was applied for assessing the quality of studies. Weighted mean difference (WMD), 95% confidence interval (CI), and random-effects model, were applied for estimating the overall effect. Between studies, heterogeneity was examined using the chi-squared and I² statistics. Nine studies met the inclusion criteria. Pooled data showed that creatine significantly reduced creatine kinase (CK) concentration overall (WMD = −30.94; 95% CI: −53.19, −8.69; p = .006) and at three follow-up times (48, 72, and 96 hr) in comparison with placebo. In contrast, effects were not significant in lactate dehydrogenase (LDH) concentration overall (WMD = −5.99; 95% CI: −14.49, 2.50; p = .167), but creatine supplementation leaded to a significant reduction in LDH concentrations in trials with 48 hr measurement of LDH. The current data indicate that creatine consumption is better than rest after diverse forms of damaging and exhaustive exercise or passive recovery. The benefits relate to a decrease in muscle damage indices and improved muscle function because of muscle power loss after exercise. Practical applications Creatine supplementation would be effective in reducing the immediate muscle damage that happens <24, 24, 48, 72, and 96 hr post-exercise. In the current meta-analysis, the positive effects of creatine could cause a decrease in CK concentration overall. But, due to high heterogeneity and the medium risk of bias for articles, we suggest that these results are taken into account and the facts are interpreted with caution by the readers.
... One to two weeks of creatine supplementation has been shown to increase total body mass by approximately 1 kg, predominately in the form of fat free mass [14,33,34]. Most of this weight gain is attributed to intra-myofibrillar water retention mediated by the sodium and amino acid concentration gradient across the sarcolemma created by creatine transportation into the muscle fiber [35]. ...
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The maximal number of repetitions that can be completed at various percentages of the one repetition maximum (1RM) [REPS ~ %1RM relationship] is foundational knowledge in resistance exercise programming. The current REPS ~ %1RM relationship is based on few studies and has not incorporated uncertainty into estimations or accounted for between-individuals variation. Therefore, we conducted a meta-regression to estimate the mean and between-individuals standard deviation of the number of repetitions that can be completed at various percentages of 1RM. We also explored if the REPS ~ %1RM relationship is moderated by sex, age, training status, and/or exercise. A total of 952 repetitions-to-failure tests, completed by 7289 individuals in 452 groups from 269 studies, were identified. Study groups were predominantly male (66%), healthy (97%), < 59 years of age (92%), and resistance trained (60%). The bench press (42%) and leg press (14%) were the most commonly studied exercises. The REPS ~ %1RM relationship for mean repetitions and standard deviation of repetitions were best described using natural cubic splines and a linear model, respectively, with mean and standard deviation for repetitions decreasing with increasing %1RM. More repetitions were evident in the leg press than bench press across the loading spectrum , thus separate REPS ~ %1RM tables were developed for these two exercises. Analysis of moderators suggested little influences of sex, age, or training status on the REPS ~ %1RM relationship, thus the general main model REPS ~ %1RM table can be applied to all individuals and to all exercises other than the bench press and leg press. More data are needed to develop REPS ~ %1RM tables for other exercises.
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Two intermittent high-intensity exercise protocols were performed before and after the administration of either creatine or a placebo, and performance characteristics and selected physiological responses were studied. Each exercise protocol consisted of 10 6-s bouts of high-intensity cycling at 2 exercise intensities (130 rev/min [EX130]: ∼820 W and 140 rev/min [EX140)]: ∼ 880 W) so that in EX130 the same amount of exercise was performed before and after the administration period, whereas an exercise intensity in EX140 was chosen to induce fatigue over the 10 exercise bouts. Sixteen healthy male subjects were randomly assigned to the 2 experimental groups. A double-blind design was used in this study. There were no significant changes in the placebo group for any of the measured parameters. Performance towards the end of each exercise bout in EX140 was enhanced following creatine supplementation, as shown by a smaller decline in work output from baseline along the 10 trials. Although more work was performed in EX140, after vs before the administration period, blood lactate accumulation decreased (mean and SEM), from 10.8 (0.5) to 9.1 (0.8) mmol·l−1 and plasma accumulation of hypoxanthine decreased from 21.1 (0.4) to 16.7 (0.8) μmol·l−1, but there was no change in oxygen uptake measured during 3 exercise and recovery periods [3.18 (0–1) vs 3.14 (0.1) l·min−1]. In EX130 blood lactate accumulation decreased, from 7.0 (0.5) to 5.1 (0.5) mmol·l−1, and oxygen uptake was also lower, decreasing from 2.84 (0.1) to 2.78 (0.1) l·min−1. A significant increase in body mass (11 kg: range 0.3 to 2.5 kg) was found in the creatine group. The mechanism responsible for the improved performance with creatine supplementation are postulated to be both a higher initial creatine phosphate content availability and an increased rate of creatine phosphate resynthesis during recovery periods. The lower blood lactate and hypoxanthine accumulation can also be explained by these mechanisms.
1. The present study was undertaken to test whether creatine given as a supplement to normal subjects was absorbed, and if continued resulted in an increase in the total creatine pool in muscle. An additional effect of exercise upon uptake into muscle was also investigated. 2. Low doses (1 g of creatine monohydrate or less in water) produced only a modest rise in the plasma creatine concentration, whereas 5 g resulted in a mean peak after 1 h of 795 (sd 104) μmol/l in three subjects weighing 76–87 kg. Repeated dosing with 5 g every 2 h sustained the plasma concentration at around 1000 μmol/l. A single 5 g dose corresponds to the creatine content of 1.1 kg of fresh, uncooked steak. 3. Supplementation with 5 g 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%. 4. Uptake into muscle was greatest during the first 2 days of supplementation accounting for 32% of the dose administered in three subjects receiving 6 × 5 g of creatine monohydrate/day. In these subjects renal excretion was 40, 61 and 68% of the creatine dose over the first 3 days. Approximately 20% or more of the creatine taken up was measured as phosphocreatine. No changes were apparent in the muscle ATP content. 5. No side effects of creatine supplementation were noted. 6. One hour of hard exercise per day using one leg augmented the increase in the total creatine content of the exercised leg, but had no effect in the collateral. In these subjects the mean total creatine content increased from 118.1 (sd 3.0) mmol/kg dry muscle before supplementation to 148.5 (sd 5.2) in the control leg, and to 162.2 (sd 12.5) in the exercised leg. Supplementation and exercise resulted in a total creatine content in one subject of 182.8 mmol/kg dry muscle, of which 112.0 mmol/kg dry muscle was in the form of phosphocreatine.
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.
1. 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 × 6 g of glucose/day, n = 6) or creatine (4 × 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. 4. There is evidence to suggest that the decrease in the degree of muscle torque loss after dietary creatine supplementation may be a consequence of a creatine-induced acceleration of skeletal muscle phosphocreatine resynthesis. It is postulated that an increased availability of phosphocreatine would maintain better the required rate of ATP demand during contraction. This is supported by the observed lower accumulation of plasma ammonia during exercise after creatine ingestion.
The effect of oral creatine supplementation on skeletal muscle ATP
  • P L Greenhaff
  • D Constantin-Teodosiu
  • A Casey
  • E Hultman
GREENHAFF, P.L., CONSTANTIN-TEODOSIU, D., CASEY, A. & HULTMAN, E. 1994b. The effect of oral creatine supplementation on skeletal muscle ATP
Effect of oral creatine supdegradation during repeated bouts of maximal voluntary exercise in man
  • P L Greenhaff
  • K Bodin
  • K Soderlund
  • Hultman
GREENHAFF, P.L., BODIN, K., SODERLUND, K. & HULTMAN. 1994a. Effect of oral creatine supdegradation during repeated bouts of maximal voluntary exercise in man. 3 Physiol467, 84P.