FREE ESSAY ON ENDURANCE

ENDURANCE

Endurance plays a major role in many athletic activities. Without endurance training, many
athletes would not be able to compete in their respective sports. Endurance training
involves low resistance and high repetitions, but what exactly does this do to your body
and how does it do it?
For starters, endurance training increases the level of certain aerobic enzymes, which
are needed for the breakdown of fuels to produce energy. Enzymes are proteins that speed
up metabolic reactions; they release and transfer energy. Enzymes are influenced by many
factors:
1) Temperature- activity is increased when the muscles are warm, therefore warming up
before the actual activity is very important
2) Acidity- lower Ph levels reduces enzyme activity, leading to fatigue
3) Fuel- enzymes work faster when they have more fuel
The faster the enzyme can breakdown your body's fuel, the faster you will receive
energy.
Training also increases the number and size of the mitochondria. Mitochondria are
cellular powerhouses that produce energy aerobically. All oxidative energy production
takes place in the mitochondria. Oxygen is the key to endurance training, so the
mitochondria are very important. Oxygen is needed to breakdown carbohydrates and fats,
which provide energy. Dr. John Holloszy conducted an experiment to prove the importance
of the mitochondria in endurance training. He had two groups of rats. One group was
trained and eventually could exercise continually for four to eight hours. The untrained
rats became tired after thirty minutes of exercise. Holloszy found a fifty to sixty
percent increase in the mitochondrial protein and a twofold increase in oxygen
consumption in the muscles of the trained rats. This also led to the conclusion that
endurance-trained muscle fibers are better able to burn fat as a source of energy.
Endurance training causes only limited gain in muscles. Muscles not involved in training
may actually lose strength. However, there may be an increase in myofibrils, but no
significant increase in muscle fibers. Evidence has shown that fast-twitch fibers take on
oxidative capabilities and assume the properties of slow-twitch fibers. Long distance
runners have as much as eighty- percent slow-twitch fibers. Training also causes an
increase in the ability of fast-twitch fibers to utilize oxygen. 
Endurance training also affects cardiac performance. The most obvious change that
training brings about is a decrease in heart rate at both resting and at a fixed
intensity. The stroke volume at all levels of physical activity is increased. The leads
to a decrease in blood pressure. There is also an increase in cardiac output; cardiac
output is the primary determinant of oxygen transport.
Respiratory performance is affected by endurance training. It increases the endurance of
chest muscles, which minimizes the loss of respiratory performance. Training also reduces
the time it takes to reach a steady breathing rate once the exercise has begun. The
ventilatory demands are decreased for four reasons:
1) Increase in muscular efficiency
2) Decrease in ventilatory drive
3) Reduction in sensitivity of carotid chemorecptors
4) Lesser production of lactate
Endurance training can cause changes in your endocrine/hormonal system. Studies have
shown the adrenal glands, which secrete epinephrine (adrenaline), enlarge with training.
Epinephrine, cortisol, thyroxine, glucagon, and growth hormones are all secreted during
exercise. Epinephrine and growth hormones are involved in the mobilization of fat. The
need for insulin, which is usually secreted after a meal, is lowered because the muscles
can take up sugar during exercise. Overall, training seems to fine tune the body's
secretion and response to hormones. This leads to a more efficient use of hormones and
energy.
The previous talks about what endurance training does to your body. Now let's look at
what it does to you psychological. Endurance athletes have been found to have healthier
mood state profiles. There are generally classified as having lower levels of tension,
depression, anger, fatigue, and confusion. However, during periods of over-training,
levels of anger, anxiety, and depression are increased. Overall though, endurance
athletes are more mentally healthy than an average athlete is.
Endurance is gained by persistency with a lighter load. This means doing maybe one set of
20-40 with ten pounds, instead of two sets of ten to twelve with twenty pounds. You
progressively increase your workload. Consistency is very important. Endurance workouts
are all week long, all year-round.
Endurance training affects every part of your body, physically and emotionally. It makes
you healthier and overall happier person. Endurance plays a major role in all of our
athletic activities.