Creatine timing on muscle mass and strength: Appetizer or Dessert?

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Abstract
Resistance training is a potent stimulus to enhance skeletal muscle hypertrophy and strength. Combining creatine supplementation with resistance training may be an effective strategy to enhance the physiological adaptations from resistance training alone. Emerging evidence suggests that the timing of creatine supplementation may be an important regulator of muscle hypertrophy and strength. Creatine ingested before and after resistance training sessions appear to be an effective strategy to increase muscle mass and strength, with slightly greater benefits if creatine is consumed after exercise compared to before. This brief review will evaluate the literature pertaining to the strategic ingestion of creatine and resistance training resulting in practical creatine supplementation strategies.
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19
Agro FOOD Industry Hi Tech - vol 25(4) - July/August 2014
KEYWORDS: supplements, creatine, strength, muscle mass, timing
AbstractResistance training is a potent stimulus to enhance skeletal muscle hypertrophy and strength. Combining
creatine supplementation with resistance training may be an effective strategy to enhance the
physiological adaptations from resistance training alone. Emerging evidence suggests that the timing of creatine supplementation
may be an important regulator of muscle hypertrophy and strength. Creatine ingested before and after resistance training sessions
appear to be an effective strategy to increase muscle mass and strength, with slightly greater benefits if creatine is consumed after
exercise compared to before. This brief review will evaluate the literature pertaining to the strategic ingestion of creatine and
resistance training resulting in practical creatine supplementation strategies.
Creatine timing on muscle mass
and strength: Appetizer or Dessert?
INTRODUCTION
It is well established that the mechanical stimuli from
resistance training increases muscle protein synthesis (1).
Although the machinery for stimulating muscle protein
synthesis is increased after resistance training (2), the
anabolic response may be delayed post-exercise (3). The
combination of creatine supplementation and resistance
training may lead to greater muscle benefits than resistance
training alone in young and older adults (4, 5). Furthermore,
the timing of creatine ingestion may be an important factor
for creating an anabolic environment for muscle growth (5).
Emerging evidence suggests that creatine supplementation,
in close proximity to resistance training sessions, may provide
superior benefits compared to creatine intake at other times
of the day (6, 7). While the mechanistic actions explaining
the greater benefits from timed creatine ingestion are
unknown, it is possible that blood flow kinetics and creatine
transport are involved (8, 9). Therefore, the purpose of this
review is to 1) briefly outline the potential beneficial effects
of creatine supplementation, 2) review the emerging
evidence involving the timing of creatine supplementation
combined with resistance training, and 3) outline creatine
supplementation strategies.
CREATINE SUPPLEMENTATION
Creatine, methyl-guanidino acetic acid, is a naturally
occurring nitrogen-containing compound (5, 10, 11).
Creatine excretion occurs at a rate of ~2 g∙d-1 (12).
Creatine can be replaced via endogenous synthesis (1-2
g·d-1) in the kidneys, liver, and pancreas or through dietary
intake, typically ~1-3 g·d-1 (11, 12). Creatine is found in high
concentrations in red meat and seafood (12). Ninety-five
percent of creatine is stored in skeletal muscle, of which
60-70 percent is phosphorylated (i.e. phosphocreatine)
(13). Phosphocreatine rapidly resynthesizes adenosine
diphopshate to help maintain adenosine triphosphate
(ATP) during high intensity exercise such as resistance
training (13). Theoretically, elevated phosphocreatine
stores (via creatine supplementation) may increase
exercise training intensity and the volume of work
performed leading to greater muscle accretion and
strength (reviewed in Branch (14); Rawson & Volek (15)).
Several purported mechanisms exists which may help
explain the typical increase in muscle mass and strength
from creatine (4, 5, 10). Creatine supplementation elevates
skeletal phosphocreatine and total creatine stores (16)
which increases phosphocreatine resynthesis (17) and
exercise fatigue resistance (18). Creatine may also
influence myocellular water retention due to increased
intracellular osmolarity and increase muscle glycogen
storage (19). Subsequent muscle cell swelling may
stimulate genes regulating various anabolic pathways (20).
Furthermore, creatine has been shown to increase satellite
cell differentiation (21), activity (22), and content (23);
transcription factor activity (24), hormonal secretion (e.g.
IGF-1;(25)), muscle protein kinetics (26), and decrease
inflammation (27).
DIETARY
SUPPLEMENTS
SCOTT C. FORBES1, XAVIER WALTZ1, DARREN G. CANDOW2*
*Corresponding author
1. University of Calgary, Faculty of Medicine, Department of Physiology and Pharmacology,
Alberta, T2N 4N1, Canada
2. University of Regina, Faculty of Kinesiology & Health Studies, Regina, S4S 0A2, Saskatchewan, Canada
Darren G. Candow
Agro FOOD Industry Hi Tech - vol 25(4) - July/August 2014
20
morning and evening
on training days, Cribb
et al. (6) showed that
creatine ingestion
before and after
exercise resulted in
significantly greater
intramuscular creatine
content, lean tissue
mass, and muscle cross
sectional-area of type II
fibres.
Although it is difficult to
compare results across
studies, it has been
theorized that these
positive results from
creatine ingestion
before and after
exercise may be due to
an increase in blood
flow and delivery of
creatine to exercising
muscles (8), an
upregulation of the
kinetics involved in
creatine transport (9),
and by an increase in Na+-K+ pump function during exercise (9).
Based on the limited studies performed thus far, it appears that
creatine supplementation before and after resistance training
sessions is important for muscle and strength. Post-exercise
creatine ingestion may provide slightly greater benefits than pre-
exercise creatine supplementation.
SUMMARY
Resistance training is an effective strategy to increase muscle
mass and strength. Emerging evidence indicates that the timing
of creatine supplementation is an important intervention for
augmenting the physiological adaptations from resistance
training alone. Creatine ingested before and after resistance
training sessions appears to be an effective strategy to increase
muscle mass and strength, with slightly greater benefits if
creatine is consumed post-exercise compared to pre-exercise.
REFERENCES AND NOTES
1. Phillips, S.M., “Protein requirements and supplementation in strength
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6. Cribb, P.J., Hayes, A. “Effects of supplement timing and resistance
CREATINE TIMING
The timing of creatine supplementation is proving to be an
important regulator of muscle growth (Table 1). The strategic
ingestion of creatine immediately before and after resistance
training sessions appears more important than ingesting creatine
at other times of the day. For example, in the most recent study,
we showed that creatine (0.1 g∙kg-1) immediately before and
immediately after resistance training sessions for 8 months
produced similar gains in muscle mass and strength. However,
compared to placebo, only post-exercise creatine resulted in
greater improvements in whole body lean tissue mass (creatine
after = 6.2 percent vs. placebo = 1.4 percent) and leg press
strength (creatine after = 28.3 percent vs. 3.4 percent;
unpublished findings). The slightly greater benefit from post-
exercise creatine supplementation indirectly supports the
findings of Antonio and Ciccone (28) who found a greater
muscle benefit from post-exercise creatine supplementation (5
g) in young adults compared to pre-exercise creatine
supplementation. We previously found no differences between
creatine supplementation (0.1 g∙kg-1) immediately before vs.
after resistance training sessions for 12 weeks in older adults (29).
However, a major limitation of the studies by Antonio and
Ciccone (28) and Candow et al. (29) was that a placebo
(control) was not used for comparison to creatine. Consuming
creatine immediately before (0.05 g∙kg-1) and immediately after
(0.05 g∙kg-1) resistance training sessions (3 days/week, 10 weeks)
resulted in greater muscle accretion (2.0 ± 0.3 cm) compared to
placebo (0.8 ± 0.3 cm) and resistance training in healthy older
males (59-77 years) (30). These results support previous findings of
a significant increase in lean tissue mass (6 percent), type II
muscle fibre area (29 percent), and insulin growth-factor I (78
percent) in adults (19-55 years) who ingested creatine before
(0.03 g∙kg-1) and after (0.03 g∙kg-1) resistance training (6 days/
week, 8 weeks) (25, 31). Interestingly, in comparing the effects of
creatine ingestion before (0.5 g∙kg-1) and after (0.5 g∙kg-1)
resistance training (10 weeks) to creatine ingestion in the
Table 1. Studies Investigation the effects of creatine timing combined with resistance training.
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supplementation before versus after supervised resistance training in
healthy older adults”, Res Sports Med, 22(1), 61-74 (2014).
30. Candow, D.G., Little, J.P., Chilibeck, P.D., et al. “Low-dose creatine
combined with protein during resistance training in older men”,
MMSE, 40(9), 1645-52 (2008).
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weight training on muscle creatine and performance in
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beneficial effect of creatine application strategies”, Biogerontology,
12(4), 273-81 (2011).
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IJSN, 5 Suppl, S100-10 (1995).
12. Wyss, M., Kaddurah-Daouk, R. “Creatine and creatinine
metabolism”, Physiol Rev, 80(3), 1107-213 (2000).
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play a role in skeletal muscle metabolism and performance?”, Am J
Clin Nutr, 72(2 Suppl), 607S-17S (2000).
14. Branch, J.D. “Effect of creatine supplementation on body
composition and performance: a meta-analysis”, IJSNEM, 13(2),
198-226 (2003).
15. Rawson, E.S., Volek, J.S. “Effects of creatine supplementation and
resistance training on muscle strength and weightlifting
performance”, JSCR, 17(4), 822-31 (2003).
16. Syrotuik, D.G., Bell, G.J. “Acute creatine monohydrate
supplementation: a descriptive physiological profile of responders vs.
nonresponders”, JSCR, 18(3), 610-7 (2004).
17. Greenhaff, P.L., Bodin, K., Soderlund, K., et al. “Effect of oral creatine
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The American journal of physiology, 266(5 Pt 1), E725-30 (1994).
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19. van Loon, L.J., Murphy, R., Oosterlaar, A.M., et al. “Creatine
supplementation increases glycogen storage but not GLUT-4 expression
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    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 (1g of creatine monohydrate or less in water) produced only a modest rise in the plasma creatine concentration, whereas 5g resulted in a mean peak after 1h of 795 (SD 104) mumol/l in three subjects weighing 76-87 kg. Repeated dosing with 5g every 2h sustained the plasma concentration at around 1000 mumol/l. A single 5g dose corresponds to the creatine content of 1.1 kg of fresh, uncooked steak. 3. 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%. 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 x 5g 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.(ABSTRACT TRUNCATED AT 250 WORDS)