Exercise Physiology

The role of an exercise physiologist is to study the way the body functions during intense physical activity. Typically working with athletes, exercise physiologists observe how each individual's body reacts to exercise, and then creates the most beneficial work-out plan for them. Exercise physiologists study athleticism from a cellular level up to the organism (human) level. 


Oxygen intake is an essential area of study for exercise physiologists, because the amount of oxygen taken in by the athlete can determine how effectively their cells can utilize energy. The oxygen intake is measured as VO₂, so the VO₂ max is a measure of aerobic endurance: the maximum amount of oxygen that can be taken in despite varying intensities of workload. To measure the VO₂ max, exercise physiologists calculate the VO₂ max by determining how many milliliters of oxygen are taken in per kilogram of body weight per minute. This measurement can be taken by a simple step test. The participant steps up and off a step, one foot at a time, at a steady rate for 3 minutes. Once the 3 minutes have elapsed, the pulse rate is recorded. Using these measurements, the aerobic endurance can be calculated. The higher the VO₂ max, the more "fit" one is considered. This is because when the oxygen intake is higher, more molecules of adenosine triphosphate (ATP) can be broken down into adenosine diphosphate (ADP) which releases large amounts of energy into the muscles.

VO2 Intake Graph

Glycolysis

There are three primary energy pathways, aerobic metabolism, anaerobic metabolism and CP metabolism. These pathways are not turned on and off separately, rather, they work cohesively, particularly in team sports. Aerobic metabolism utilizes aerobic respiration, which can sustain an athlete for longer periods of time because the oxygen intake is utilized to break down ATP, releasing energy. Aerobic metabolism is typically used by long distance runners. Anaerobic metabolism utilizes anaerobic respiration. This is performed through glycolysis, the process that converts glucose into pyruvate resulting in the creation of ATP. In this form of respiration, oxygen is not required. However, the utilization of anaerobic respiration for too long a time causes lactic acid build up, which results in the body becoming fatigued. Anaerobic metabolism is typically utilized by sprinters. Sprinters also take advantage of CP metabolism (also known as the ATP-CP metabolism or ATP-CP system), a process that first breaks down the ATP reserves in the body and then breaks down creatine phosphate to resynthesize ATP. Once the creatine phosphate runs out, then the sprinter returns to aerobic or anaerobic metabolism. The CP energy pathway allows for short bursts of intense energy for rapid movements.

Energy Pathway

Glucose to ATP, ADP and CP

An athlete's diet is an essential part of their success. Since ATP and CP stores in the body are relatively small, glycogen, fat and protein stores allow for quick replenishment. Exercise physiologists suggest a diet of 55% carbohydrates which supply the glycogen stores which are used for short-term energy storage, 30% fats which are used for long-term energy storage, and 15% proteins, which, although they are not typically used as energy stores, they should be consumed to maintain the health of the muscles.

Suggested Diet Graph