Endurance Essay, Research Paper

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.