December 1, 1998
Volume 1, Number 9
Research Update
by Bryan Haycock MSc., CSCS
bryan@thinkmuscle.com
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on this article.
As we approach the new millennium we find the science of building
muscle progressing faster than ever before. Long gone are the days of
simple trial and error when it comes to building muscle. The modern
bodybuilder demands more than just "hear say" if they are to
adopt a new training routine or nutritional supplement. This column was
created to keep today’s bodybuilder on the cutting edge of scientific
research that might benefit them in their quest for body perfection.
Are you cycling your creatine? Find out why you should.
Title:
Creatine supplementation in health and disease. Effects of chronic
creatine ingestion in vivo: down-regulation of the expression of
creatine transporter isoforms in skeletal muscle.
Researchers:
Guerrero-Ontiveros ML, Wallimann T.
Institute for Cell Biology, Swiss Federal Institute of Technology,
ETH-Honggerberg, Zurich.
Source:
Mol Cell Biochem 1998 Jul;184(1-2):427-37
Summary:
These researchers studied the in vivo effect of dietary
creatine as well as 3-GPA (a creatine analog that is a competitive
inhibitor of creatine entry) on the expression of the creatine
transporter (creatine T). Long term feeding of rats with 3-GPA has been
previously shown to decrease creatine levels in skeletal muscles without
effecting creatine T expression. In this study, the expression of the
creatine T was examined in rats chronically fed either 4% creatine or
2.5% GPA. Dietary creatine administered for 3-6 months, significantly
lowered the expression of creatine T polypeptides. The rats fed the
creatine analog GPA showed virtually no change (perhaps even a slight
increase) in creatine T polypeptide expression.
Discussion:
The wide spread use of creatine among athletes and bodybuilders has
raised concerns about possible negative side effects. Of course most of
the nay sayers are looking to control its availability with little real
concern for the well being of those who use it. This study has answered
a question that has rested on the minds of many, which is, "Is
there any reason to cycle creatine?" From the study above we see
that the abundance and activity of the creatine transporter is
negatively effected by long term creatine ingestion. The creatine
transporter is down regulated with continued exposure to extracellular
creatine.
Human skeletal muscle has an upper limit of creatine that can, or
will, be contained within the cell. This limit is around 150-160 mmol/kg
of dry muscle. As the intracellular concentration of creatine approaches
this level, the synthesis of creatine transporters declines and even
stops depending on the amount of creatine ingested over time. In the
study above, it was shown that the creatine transporter is regulated by
the content of creatine in the cell rather than by the interaction of
creatine, or it’s analog 3-GPA, with the transporter.
All the arguments about creatine absorption being a limiting factor
in creatine content within the cell are bogus. Creatine does not need to
be "micronized" or "effervesent" to lead to an
increase in creatine content within your muscles. The activity of the
creatine transporter is the limiting factor. Any trick increase in
creatine absorption will only hasten creatine transporter down
regulation. It only requires about 5 grams per day for 30 days to
increase the content of creatine within muscle tissue to the same extent
as 30 grams per day for 6 days. The sooner you reach the upper limit the
sooner your muscles become unable to take up creatine. It is better to
maintain sufficient levels of creatine transporters in order not to
cause a rapid decline in creatine content once creatine supplementation
is discontinued. Clearly there appears to be good reason to cycle
creatine supplementation. The authors of this study recommend not using
creatine for over 3 months at a time. A one month period in between with
no creatine supplementation should then be sufficient to allow creatine
transporter synthesis to begin again.
Researchers too quick to blame steroids for changes in heart muscle.
Title:
Left ventricular wall thickening does occur in elite power athletes
with or without anabolic steroid Use.
Researchers:
Dickerman RD, Schaller F, McConathy WJ
Department of Biomedical Sciences, University of North Texas Health
Science Center, Fort Worth, Tex., USA.
Source:
Cardiology 1998 Oct;90(2):145-8
Summary:
Researchers examined 4 elite resistance-trained athletes by
two-dimensional echocardiography. In addition, they retrospectively
examined the individual left ventricular dimensions of 13 bodybuilders
from our previous echocardiographic studies. All 4 elite
resistance-trained athletes had left ventricular wall thicknesses beyond
13 mm. One of the elite bodybuilders has the largest left ventricular
wall thickness (16 mm) ever reported in a power athlete.
Retrospectively, 43% of the drug-free bodybuilders and 100% of the
steroid users had left ventricular wall thickness beyond the normal
range of 11 mm. In addition, 1 drug-free subject and 3 steroid users
were beyond the critical mark of 13 mm. No subjects demonstrated
diastolic dysfunction. In contrast to previous reports, we have
demonstrated that left ventricular wall thicknesses >/=13 mm can be
found routinely in elite resistance-trained athletes who do not use
anabolic steroids.
Discussion:
Left ventricular hypertrophy is characterized by thickening of the
left ventricular wall secondary to cardiac fiber enlargement. Left
ventricular hypertrophy is normally caused by a chronic increase in
systemic blood pressure. It may also be seen with sudden or rapid weight
gain. The thickening of the ventricular wall due to increased afterload
from elevated vascular resistance can be viewed as adaptive protection
up to a point. Beyond minor wall thickening, left ventricular
hypertrophy is a strong predictor of serious cardiovascular risk.
During heavy lifting, systemic blood pressure is increase from what
is called the valsalva maneuver. It is simply the act of forceful
expiration with the mouth and nose closed producing a "bearing
down" on the abdomen. Pressure also increases due to blood vessels
being occluded by contracting muscles. It should be noted that the LVH
seen in bodybuilders and power lifters is called "concentric left
ventricular hypertrophy", meaning that it is the result of
contracting against acute increased systemic pressure, and was not
considered pathological. "Eccentric" LVH is caused by constant
increases of blood pressure not as a result of the valsalva maneuver but
instead clinical hypertension that forces the ventrical to expand
against resistance. It was previously believed that the intermittent
increase in blood pressure that is caused by heavy lifting was not
sufficient to elicit left concentric ventricular hypertrophy (CLVH). Any
evidence of CLVH in strength athletes or bodybuilders was seen as a sign
of anabolic steroid use.
In the study above researchers identified LVH at or beyond 13mm in
not only bodybuilders using anabolic steroids but also in "drug
free" athletes as well. Although it was shown that those using
anabolics showed significantly more ventricular thickening, at least one
drug free athlete was beyond the 13mm limit.
Are meal replacement drinks really that important after your workout?
Read on and decide for yourself.
Title:
Hormonal responses to consecutive days of heavy-resistance exercise
with or without nutritional supplementation.
Researchers:
Kraemer WJ, Volek JS, Bush JA, Putukian M, Sebastianelli aWJ
The Human Performance Laboratory, Ball State University, Muncie, Indiana
47306, USA.
Source:
J Appl Physiol 1998 Oct;85(4):1544-55
Summary:
Nine resistance-trained men consumed either a protein-carbohydrate
supplement (Twin Lab’s MassFuel) or placebo for 1 wk in a crossover
design separated by 7 days. The last 3 days of each treatment, subjects
performed resistance exercise. The supplement was consumed (half
serving) 2 h before and immediately after (half serving) the workout,
and blood was obtained before and after exercise (0, 15, 30, 45, and 60
min postexercise). Lactate, growth hormone, and testosterone were
significantly (P </= 0.05) elevated immediately postexercise in both
placebo and supplemented groups. The lactate response was significantly
lower during supplementation on days 2 and 3. Growth hormone and
prolactin responses on day 1 were significantly higher during
supplementation. After exercise, testosterone declined below resting
values during supplementation. Cortisol decreased immediately
postexercise on day 1; the response was diminished on days 2 and 3.
Glucose and insulin were significantly elevated by 30 min during
supplementation and remained stable during placebo. Insulin-like growth
factor-I was higher during supplementatiom on days 2 and 3. These data
indicate that protein-carbohydrate supplementation before and after
training can alter the metabolic and hormonal responses to consecutive
days of heavy-resistance exercise.
Discussion:
The reason for performing this study was to see what would happen
after consecutive days of training and supplementation with a
carb/protein drink. Most all previous studies looking at the effect of
macronutrient supplementation are done acutely after a single bout of
exercise.
The results of this study are not surprising. There was a significant
increase in post-exercise glucose and insulin due to the carbs and BCAAs
in the supplement drink. As with previous studies, there was also an
increase in post exercise growth hormone however, it was only greater
than placebo after the first workout. After the second and third
workouts the differences were very small. There was a significant
increase in resting IGF-1 levels in the supplemented group with no
difference in post exercise levels when compared to placebo. This is not
unusual in conditions of "over feeding". The supplement added
between 1575 - 2475 kcals per day in this study.
There was a trend for reduced cortisol levels for both placebo and
the supplement groups. Surprisingly, cortisol levels were not greatly
different after post exercise supplementation. Performance appeared to
be unaffected by supplementation. This is not unusual after such a short
training protocol (3 days). There was one significant difference that
should be noted, namely serum testosterone was significantly lower
in the MassFuel group. The authors explained this observation from a
macro nutrient ratio perspective. You see, while supplementing with
MassFuel the percentage of calories from fat drops to 14% compared to
24% for the placebo period. It is well known that the highest resting
testosterone levels are achieved when fat provides ~30% calories. It can
be optimistically speculated that free testosterone levels remained the
same from data measuring the ratio of total serum test and SHBG.
What is the take home message from all this? First, there was
virtually no difference in the way the body responded to three
consecutive days of training the same body parts. This may lead to new
ideas about how often to train an individual muscle. It is not
unreasonable to consider training a body part for two or three days in a
row and then giving it 5-7 days off. And finally, from last month’s
Research Update we saw that critical initiation factors (eIF4E, etc.)
that control protein synthesis are regulated by post exercise insulin
and cortisol levels as well as the availability of amino acids. By using
a carb/protein supplement in liquid form after training you can ensure
that protein synthesis will begin as soon as possible after exercise.
by Bryan Haycock MSc., CSCS
bryan@thinkmuscle.com
Please send us your feedback
on this article.
