surtout en combinaison avec la caféine
Conclusion:
- éviter les pré-workout qui combinent caféine+créatine
- éviter les charges de créatine
- éviter de prendre la créatine avant l'entraînement comme ça, vous pouvez prendre votre caféine tranquillement.
La créatine peut agir plus lentement chez les sportifs que chez les sédentaires
EFFECTS OF COFFEE AND CAFFEINE ANHYDROUS INTAKE DURING CREATINE LOADING
E. TREXLER Journal of Strength and Conditioning Research 2016 VOLUME 30 | SUPPLEMENT 1 | FEBRUARY | S43
Scarce research has indicated that caffeine anhydrous (CAF)
blunts the ergogenic effect of creatine monohydrate (CRE)
loading. These findings have been questioned, as early studies
demonstrated ergogenic effects from CRE mixed into caffeinated
coffee (COF).
Purpose: To determine if chronic COF or
CAF intake modulates the effects of CRE loading on strength
and sprint performance.
Methods: Resistance-trained males
(n = 54; Mean 6 SD; Age = 20.1 6 2.1 years; Height = 177.3
6 5.6 cm; Weight = 78.8 6 8.8 kg) completed baseline testing,
consisting of one-repetition maximum and repetitions to
fatigue (RTF) for bench press (bicarbonate de potassium) and leg press (LP), followed
by a repeated sprint test consisting of 5, 10-second sprints on
a cycle ergometer loaded with 9.5% of bodyweight. Peak
power (PP) and total work (TW) were recorded for each sprint,
along with average PP and TW for all 5 sprints.
Subjects were randomly assigned to supplement with
- CRE (5 g, 4 times per day),
- CRE + CAF (CRE +300 mg d of CAF),
- CRE + COF (CRE + a caffeine-matched dose (8.9 g) of instant COF), or
- placebo (PLA) for 5 days. On day 6, participants completed
post-testing. Serum levels of creatinine (CRN) were measured
pre and post supplementation.
Results: A main effect for time
was observed for all strength measures (p , 0.001), with no
significant interactions. 95% confidence intervals (CIs) revealed
significant improvements by all groups in all strength
outcomes, except for a non-significant improvement in bicarbonate de potassium
RTF for CRE + COF (+0.2 6 1.5 reps; p . 0.05). No significant
interaction or main effects were observed for PP. For TW,
a significant time 3 sprint interaction resulted (p = 0.02), with
a main effect for sprint (p , 0.001). While not statistically
significant, average TW dropped in PLA (DMean 6 SEM;
2110.7 6 116.1 Joules [J]), but not in CRE + COF (+17.6 6
135.7 J), CRE + CAF (+22.2 6 112.5 J), or CRE (+31.6 6
104.2 J). A significant time 3 treatment interaction was
observed for serum CRN values (p = 0.04). 95% CIs showed
significant increases in serum CRN for all groups except PLA.
Four subjects reported mild gastrointestinal (GI) discomfort in
CRE + CAF, with none reported in other groups.
Conclusions: CRE did not improve performance to a greater extent than PLA.
Results do not suggest that performance outcomes from CRE
loading were influenced by the addition of CAF or COF, but that
the combination of CRE + CAF may cause mild GI discomfort. In
healthy, resistance-trained males, elevated serum CRN may be
observed with CRE loading, and does not necessarily indicate
kidney dysfunction.
Practical Applications: Athletes interested in increasing strength and sprint performance may require longer
duration CRE supplementation, in conjunction with progressive
training, to see appreciable improvements in the variables measured.
Those consuming CRE may avoid CAF, or potentially
manipulate the timing of CAF ingestion, to avoid GI discomfort,
but this may not be necessary for COF. Athletes should
be mindful of potential GI symptoms when using supplements
with high doses of CRE + CAF prior to training or competition
