Creatine Research
Update
Creatine helpful in muscular dystrophies
The authors assessed the safety and efficacy
of creatine monohydrate (Cr) in various
types of muscular dystrophies in a
double-blind, crossover trial. Thirty-six
patients (12 patients with
facioscapulohumeral dystrophy, 10 patients
with Becker dystrophy, 8 patients with
Duchenne dystrophy, and 6 patients with
sarcoglycan-deficient limb girdle muscular
dystrophy) were randomized to receive Cr or
placebo for 8 weeks. There was mild but
significant improvement in muscle strength
and daily-life activities by Medical
Research Council scales and the
Neuromuscular Symptom Score. Cr was well
tolerated throughout the study period.
Walter MC. Creatine monohydrate in muscular
dystrophies: A double-blind,
placebo-controlled clinical study. Neurology
2000 May 9;54(9):1848-50. Friedrich-Baur-Institute,
Ludwig-Maximilians-University of Munich,
Germany. Maggie.
PURPOSE: The purpose of this investigation
was to examine the effects of 6 wk of oral
creatine supplementation during a periodized
program of arm flexor strength training on
arm flexor IRM, upper arm muscle area, and
body composition.
METHODS: Twenty-three male volunteers with
at least 1 yr of weight training experience
were assigned in a double blind fashion to
two groups (Cr, N = 10; Placebo, N = 13)
with no significant mean pretest one
repetition maximum (IRM) differences in arm
flexor strength. Cr ingested 5 g of creatine
monohydrate in a flavored, sucrose drink
four times per day for 5 d. After 5 d,
supplementation was reduced to 2 g x d(-1).
Placebo ingested a flavored, sucrose drink.
Both drinks were 500 mL and made with 32 g
of sucrose. IRM strength of the arm flexors,
body composition, and anthropometric upper
arm muscle area (UAMA) were measured before
and after a 6-wk resistance training
program. Subjects trained twice per week
with training loads that began at 6RM and
progressed to 2RM.
RESULTS: IRM for Cr increased (P < 0.01)
from (mean +/- SD) 42.8 +/- 17.7 kg to 54.7
+/- 14.1 kg, while IRM for Placebo increased
(P < 0.01) from 42.5 +/- 15.9 kg to 49.3 +/-
15.7 kg. At post-test IRM was significantly
(P < 0.01) greater for Cr than for Placebo.
Body mass for Cr increased (P < 0.01) from
86.7 +/- 14.7 kg to 88.7 +/- 13.8 kg.
Fat-free mass for Cr increased (P < 0.01)
from 71.2 +/- 10.0 kg to 72.8 +/- 10.1 kg.
No changes in body mass or fat-free mass
were found for Placebo. There were no
changes in fat mass and percent body fat for
either group. UAMA increased (P < 0.01) 7.9
cm2 for Cr and did not change for Placebo.
CONCLUSION: Creatine supplementation during
arm flexor strength training lead to greater
increases in arm flexor muscular strength,
upper arm muscle area, and fat-free mass
than strength training alone. Reference:
Becque MD, Lochmann JD, Melrose DR. Effects
of oral creatine supplementation on muscular
strength and body composition. Southern
Illinois University at Carbondale,
Department of Physical Education,
62901-4310, USA.
--
Creatine monohydrate (CrM) administration
may enhance high intensity exercise
performance and increase body mass, yet few
studies have examined for potential adverse
effects, and no studies have directly
considered potential gender differences.
PURPOSE: The purpose of this study was to
examine the effect of acute creatine
supplementation upon total and lean mass and
to determine potential side effects in both
men and women.
METHODS: The effect of acute CrM (20 g x
d(-1) x 5 d) administration upon systolic,
diastolic, and mean BP, plasma creatinine,
plasma CK activity, and body composition was
examined in 15 men and 15 women in a
randomized, double-blind experiment.
Additionally, ischemic isometric handgrip
strength was measured before and after CrM
or placebo (PL).
RESULTS: CrM did not affect blood pressure,
plasma creatinine, estimated creatinine
clearance, plasma CK activity, or handgrip
strength (P > 0.05). In contrast, CrM
significantly increased fat-free mass (FFM)
and total body mass (P < 0.05) as compared
with PL, with no changes in body fat. The
observed mass changes were greater for men
versus women.
CONCLUSIONS: These findings suggest that
acute CrM administration does not affect
blood pressure, renal function, or plasma CK
activity, but increases FFM. The effect of
CrM upon FFM may be greater in men as
compared with that in women. Mihic S,
MacDonald JR, McKenzie S, Tarnopolsky MA.
Acute creatine loading increases fat-free
mass, but does not affect blood pressure,
plasma creatinine, or CK activity in men and
women. Med Sci Sports Exerc 2000
Feb;32(2):291-6. Department of Kinesiology,
McMaster University, Hamilton, Ontario,
Canada.
Written by
Ray
Sahelian, M.D.
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