Exercise Physiology

“Fitness is a journey, not a destination. It must be continued for the rest of your life.” - Dr. Kenneth Cooper, the Father of Aerobics

http://www.bodyfitnt.com.au/exercise-physiology.php

Exercise physiologists are experts who study how the body functions during rigorous activity. They can test how hard an athlete is working, and then can create training programs to enhance his or her performance.

One of the most useful measurements for an exercise physiologist is the VO₂ max of an athlete, usually measured in milliliters per kilogram of body weight per minute. It is defined as the maximum amount of oxygen a person can take in while exercising. As we run, our need for energy increases. Oxygn helps the body react ADP (adenosine diphosphate) with another phosphate in order to make ATP (adenosine triphosphate), the body's main source of energy. Since oxygen is a contributor to energy production, our oxygen uptake must increase to meet the demand. Having a higher VO₂ max signifies better endurance and thus better fitness. Exercise physiologists work to increase the VO₂ max by challenging athletes to perform at or near their recorded oxygen uptake.

There is a small amount of ATP within the myofibrils of muscles, but there's only enough for one explosive reaction. Therefore, it must be replenished by constantly reacting ADP and phosphate. This is done through a number of energy pathways. Sports that require short explosive moments only need the ATP already reserved in muscles, so athletes who participate in power-lifting rely on ATP splitting as their energy pathway.

http://www.emc.maricopa.edu/

At my high school, I'm a sprinter on the track team. Sprinting requires quick repeated muscular contractions, so it uses CP (creatine phosphate) splitting to resynthesize ATP. There is a certain reserve of CP molecules in the muscles that can be used for this process, but there is only enough to last a few seconds. Luckily, that is exactly how long many short sprint races last. However, I have also run the 400 meter dash before, which is the longest sprint at a track meet. For that race, another energy pathway must be utilized, known as anaerobic glycolysis. In glycolysis, a polysaccharide known as glycogen stored in the muscles is used to create more ATP molecules. Turning the glycogen into ATP creates a byproduct known as lactic acid, and when lactic acid builds up, it causes a painful sensation in the muscles. However, athletes can be trained to perform despite this pain. One of my least favorite workouts during Track season is called "Broken Quarters." In this workout, I sprint to build up lactic acid, and then I continue to run as hard as I can so that I can train my body to handle that much lactic acid in the muscles. By doing this, I increase my anaerobic threshold, the point at which the buildup of lactic acid exceeds its removal.

http://www.lollylegs.com/training/SprintTech.aspx

If the body is too fatigued from the lactic acid, then anaerobic respiration is no longer a viable source of energy. Aerobic respiration is used to sustain long-distance running by using the circulatory system to transport the oxygen in the blood to the muscles in order to create ATP in muscles. In team sports, athletes often have to utilize multiple pathways at times to replenish ATP; in other words, these energy pathways are not mutually exclusive. They form an energy continuum, and exercise physiologists will often create workouts that help an athlete's use of the pathways more efficient.

Besides exercise, an athlete's diet is critical to their success. Most exercise physiologists would agree that a typical athlete's diet should be 30% fat, 55% carbohydrates and 15% protein. Both fats and carbs are necessary to replenish ATP and CP reserves in the body. Fat is important to the diet, because there is a high concentration of fat in the body which is used as long-term energy storage. Carbohydrates, however, make up the majority of the diet because they are used for short-term energy storage, which is what athletes rely upon if they are going to be active for more than a couple minutes. Protein is not typically used as an energy source, but it is still important to consume so that the muscles in which all of these energy pathways take place can remain healthy.

http://healthguide.howstuffworks.com/

While conditioning is crucial to a proper training program, more studies are beginning to show that weight training is an effective way to improve athletic performance. Weight lifting is by far my favorite physical activity. Not only does it help me during Track season, but it also releases endorphins in the body that make me feel better. The principles of weight lifting are straightforward: first, there is the overload principle. This means choosing to lift weight that is challenging but not dangerous for the body. By doing this, you successfully tear muscle fibers, so that during the recovery stage when you are not lifting, they can repair themselves bigger than before to accomodate heavier weight. This is known as hypertrophy.

Because muscles will eventually adapt to meet the challenge required by repeated lifting, it is important to fulfill the principle of progression. This means constantly finding new challenges for the body to meet so that it can still tear those strengthened muscle fibers, thus inducing stress. When experiencing muscular fatigue, the body releases many hormones, including testosterone and endorphins. For overall health, it is essential to work out all of the various muscles in our body. The principle of specificity, which states that to increase strength and/or size in a certain muscle, that muscle must be trained, helps meet this need. Because muscles pull, never push, they must work in antagonistic pairs (for example, biceps and triceps). Therefore, in order to allow for the body to function properly, it is important to work both sides of the pair evenly. Lastly, it is essential to give the muscles rest (around 45-60 seconds in between 2-3 sets of an exercise) in order to give them time to repair.