Essay/Term paper: Blood and excerise

Essay, term paper, research paper:  Term Papers

Blood and Excerise


Type II muscle fibers oxidize lactate at a very fast rates. When muscle
contraction produces a significant amount of lactate, it is then released into
the central circulation of the blood, and within seconds it is made available to
that muscle for energy. Therefore, 75% of the lactate produced from high
intensity exercise is made available for energy production in type II muscle
fibers. The remaining 25% of lactic acid is used for energy in the heart, the
make up of liver glycogen, and the supply of energy to inactive muscles. A good
example of this would be a runner who is exceeding his or her planned race pace
in a 10k. The excess lactic acid accumulated in the contracting muscle from
insufficient oxygen is then made available to inactive muscles (e.g., the arms)
from the central circulation of blood. The remaining lactic acid that is not
directly oxidized for fuels is sent to the liver, where it is stored as glycogen.
In the process of exercise, glycogen is released into the blood stream to form
glucose.

Lactate is Good

As coach and athlete you must learn how to teach the body to handle lactic acid.
It is imperative, if you want successes in today's highly competitive field of
athletics to train your muscles, body and mind to accomplish gains in
performance even in the presence of lactic acid. Coaches and athletes should
design training programs with this being a primary focus. This is done by two
basic components of training. Long Slow Distance (LSD) training beyond the
normal racing distance, will develop tissue enzyme adaptations that will rely
upon the use of free fatty acids for energy production, which will result in
less lactic acid being produced. LSD training will also increase the rate of
lactic acid removal from the blood and muscles. During continuos steady state
exercise, you increase capillary density and mitochondria function in skeletal
muscle, These two peripheral adaptations brought on by LSD training will enable
your body to handle lactic acid much more efficiency. High intensity training
will develop the cardiovascular system to increase the rate of oxygen transport
to the contracting muscles so there is less reliance on carbohydrate breakdown
to lactic acid. High intensity training such as intervals., and variable pace
workouts, will increase your functional capacity (Max VO2). This means that in
actual competition you will produce less lactic acid, because your muscles are
relying mostly on the use of free fatty acids for fuel. The lactic acid that is
produce will be removed by the tissues that can use it as fuel, such as the
heart and type II muscle fibers.

More On Aerobic Type Training

When it comes right down to it, the main way to increase oxygen uptake is to do
distance, plain and simple. Generally speaking, Type I muscle fibers (the
endurance fibers) are the fibers which must be trained in order to raise VO2 Max,
But, what exactly does raising VO2 Max entail and what is happening. VO2 Max is
comprised of several factors: VO2 = Q X (A-Vo2 difference) where Q = Heart rate
* volume of blood pumped per beat and (A-Vo2 difference) is the amount of oxygen
extracted by the muscle. So, there are three things involved. Well, since, by
definition VO2 Max will be highest at maximum heart rate, it would be great if
you could raise this. Unfortunately, maximum heart rate is genetically
determined and does not change with training (although it does decrease with
age). One of the effects of prolonged endurance training is an increase in heart
size and pumping strength. These two factors see to raise the volume of blood
which can be pumped per beat. Incidentally, this is also part of why aerobic
athletes have very decreased resting heart rates. Actually, their Q values are
the same as sedentary people, it's just that since their heart can pump more
blood in a given beat, the heart doesn't have to beat as often at rest. Well,
another adaptation to endurance exercise is an increase in aerobic enzymes in
the muscles and an increase in mitochondria density and number. This serves to
increase the (A-V02 difference) as the muscles are now capable of extracting
more oxygen from the blood. This increase generally occurs the most in the Type
I fibers which have the most aerobic enzymes and mitochondria to begin with.
Hence, in order to improve VO2 Max, it is necessary to both stress the heart to
improve stroke volume and also the Type I muscle fibers to get the necessary
enzymatic changes to occur. Basically, the key to both of these is duration.
Also, note that, in order to be competitive in endurance events, you cannot do
only distance work. Although much of the race may be done at low intensities,
there will be times (hills, final sprints) when you need to go faster than your
easy pace. If all you've done is distance work, you'll get blown away during
these times. That's' why its imperative to include an anaerobic component to
your training (intervals) to compliment the aerobic conditioning to race
successfully.

AT Training

Anaerobic Threshold Conditioning works in two ways. The first is an increase in
maximal heart rate due to a rise in cardiac output and stroke volume. The second
is the specific training of Type IIa muscle cells, which have some aerobic
capacities, unlike Type IIb (which is also a Fast Twitch muscle fiber, but has
no aerobic capabilities). AT training enhances aerobic enzyme activity and
muscle density in the Type II cells, giving them a greater ability to supply O2
for the energy you need when racing at high speeds. The way to achieve these
gains is through intervals. Intervals are designed to bring heart rate, cardiac
output and 02 intake to maximal values, which help you obtain those last little
gains in VO2 your economy. We all reach a point in our fitness where it is very
difficult to improve our performance even the slightest bit. Intervals will work
on your cardiovascular system, improving O2 delivery and efficiency rates,
giving you a boost in ability. More importantly, they will allow you to exercise
continually at a higher percentage of your functional capacity. AT Training Can
Improve Performance By 7-8%.

Researches have shown that a trained endurance athlete can improve his or her
performance by 7-8% by including AT work in the weekly workout. A 7% increase
in aerobic capacity could mean a considerable time difference in a 10k
performance. For example, if you complete the 10k in 38 minutes, a 7% increase
in your aerobic capacity could allow you to better your best time by a little
over 2 minutes. The reason for this increase is that with AT training you train
your 02 system to work more efficiently. In order to improve your oxygen
delivery system adequately enough to get these benefits it's necessary to
perform anaerobic conditioning which, contrary to popular belief, does not
necessarily mean exercising without oxygen. Anaerobic simply means that you
can't supply enough 02 or energy to the active muscles in order for them to
constantly rely upon fat and glycogen as their sole energy source. At high
intensity exercise there is not enough 02 provided. Thus you slip into
anaerobic metabolism, which involves the breakdown of glucose to pyruvic acid
and lactate acid without the presence of 02. This makes up the difference and
supplies additional energy to your muscles to keep them going. There are
several different types of AT training that one can do to enhance the oxygen
delivery system, including Long Fast Distance Variable Pace, Fartleks, and Tempo
runs.