BY TIM N. ZIEGENFUSS, PHD, CSCS, FISSNhopes of sparing muscle
protein breakdown, restoring
anabolic signaling, and
(potentially) up-regulating
fat loss. The BCAA are
unique among amino acids
because they are the only
ones thought to bypass the
liver and be metabolized
directly in skeletal muscle.
Even though all three BCAA
utilize the same mechanism
(transporter) to enter muscle,
most experts advise against
taking high doses of just one
amino acid, and I generally
agree with this assertion
because when only one
BCAA is available to the body,
the other two can become
“rate limiting”. In other
words, leucine works best
to stimulate muscle protein
synthesis when isoleucine
and valine are also around
at normal “permissive”
levels. Typically, BCAA are
used several times per day,
particularly during dieting
phases or when muscles are
especially sore from training.
Experimentally, BCAA havealso been shown to help
speed muscle recovery from
intense training. Although
the mechanisms are not
completely clear, it appears
that BCAA act as signaling
nutrients and are able to
promote the phosphorylation
of proteins directly involved
in muscle protein synthesis
(mTOR, eukaryotic initiation
factors, etc). A recent study
showed that low doses of
whey protein (i.e. 6.25 grams)
can be as anabolic as higher
doses (i.e. 20 grams) if extra
leucine is added into the
whey mixture. I’d speculate
that even greater increases
would be observed if a
blend of BCAAs were utilized
rather than straight leucine.
In addition, some scientists
have speculated that long-
term use of BCAA may also
aid in fat loss efforts, as
isoleucine has been shown
to increase the activity of
genes controlling fat burning
and decrease the activity of
genes controlling fat storage.
Some data also exist that
shows leucine itself can
increase fatty acid oxidation
and increase mitochondrial
biogenesis (translation: more
mitochondria) in both muscle
cells and fat cells.
BCAA are versatile
compounds that can enhance
the effects of intense training
programs. If you don’t eat 4-5
moderate sized meals a day,
adding BCAAs to your diet
can probably help you.CITRULLINE is a naturally
occurring, chemical cousin
of the amino acid arginine.
Its name is derived from
the scientific name for
watermelon (Citrullus
vulgaris), the food from which
it was first isolated. During
its normal metabolism in the
body, citrulline is synthesized
from glutamine and ornithine
in the intestines, converted
to arginine in the kidneys, and
helps stimulate nitric oxide
(NO) production in peripheral
tissues. Of its many roles
within the body, NO causes
arterial blood vessels to
dilate, thus improving blood
flow to active muscles. Many
body builders use citrulline to
amplify their pump response
to training. Experimentally,
a few recent studies haveshown that oral citrulline
supplementation can enhance
muscular performance and
reduce fatigue by enhancing
the resynthesis of high-energy
phosphates (ATP and creatine
phosphate) that are used
during all-out exercise.
Whether you prefer drinking
watermelon concentrate or
using supplements, at the
right dose citrulline malate can
improve exercise capacity and
muscle function.BETA ALANINE is a widely
popular amino acid in many
types of athletes because
it reduces muscle fatigue
during intense exercise. When
beta alanine is ingested, it
combines with another amino
acid called histidine to form
a potent compound called
carnosine. In exercising
muscle, carnosine acts as a
potent buffer of hydrogen ions
that are generated from lactic
acid (lactate) production. This
is relevant to body builders
during sets that last longer
than about 60 seconds or
when training with short
rest periods where lactate
accumulation can reduce the
total number of repetitions
completed. In theory, beta
alanine may also be useful
during very low carb diets to
offset changes in pH due to
ketone production. For best
results, beta alanine must be
consumed continuously for at
least four weeks.
Beta alanine helps reduce
fatigue during intense body
building exercise, thus allowing
for a greater training stimulus.
All other things being equal,
a greater training stimulus =
greater gains over time.FLEXONLINE.COM 91