Introduction
The basis of this lab is formulated around the calculation and analysis of VO2 max in one individual using the Rockport Fitness Walking Test. Maximum oxygen consumption, or VO2 max is a measure of the maximum volume of oxygen, in millilitres, that the cells of the body can remove from the bloodstream in one minute per kilogram of body mass while the body experiences maximal exertion. An individual's overall fitness can be accessed through a variety of different tests and criteria including aerobic fitness, muscular strength, muscular endurance, flexibility and body composition. Aerobic fitness is a measure of the ability of the heart, lungs, and bloodstream to supply oxygen to the cells of the body during physical activity. As a result, the VO2 max value can be used to assess a portion of an individual's overall physical health.
Although VO2 max may be used to measure a portion of an individual's overall health it is not the defining factor in one's athletic ability. Athletic performance is affected by a myriad of factors including the efficiency of motion and the lactate threshold of the individual. At certain points in exercise lactic acid is produced in large values and leads to the burning sensation felt in the muscles. Based on genetics VO2 max and the lactate threshold varies between individuals. Although both can be increased with exercise and a healthy lifestyle some individuals are simply not capable of overcoming certain barriers based on their physical formulation.
In this lab a true VO2 max measurement was not completed; instead, an estimation of VO2 max was calculated from a collection of data. The Rockport Fitness Walking Test consists of a 1.6km walk and a collection of different data points which are placed into an equation to derive an estimation of VO2 max. The age, weight, gender, walk time, and heart rate of an individual is all taken into consideration when making the final calculation. By including many of the factors that affect VO2 max a fairly accurate estimation can be developed.
Methodology
The calculation of the VO2 max required the collection of various data points. To record the data points a table was made which included space for mass in kilograms, age in years, time of the walk in minutes, heart rate in beats per minute, and gender where a value of either one or zero was selected for male and female respectively. Height in centimetres and the overall average of last semester in percent were also recorded for further analysis. Using a bathroom scale the weight in kilograms was measured and recorded accurate to one decimal place. Height was then measured using a measuring tape and recorded in the chart. Exact age in years was calculated by comparing the birthday of the subject to the exact day at which the trial was completed. The average mark of last semester was also recorded in the table. The subject then prepared to walk 1.6km. The subject walked 1.6km while timing the walk using a stopwatch. Upon the completion of the walk the time which the walk took was recorded along with the heart rate of the subject. All of the recorded values were placed in an equation and a VO2 max estimation for the subject was generated.
Results
Raw Data Collection Chart
| Mass (kg) | Age (Years) | Gender (1-Male/0-Female) | Time (Minutes) | Heart Rate (Beats/Minute) | Height (cm) | Average Mark (Percentage) |
| 63.5 | 18.16 | 1 | 13.34 | 78 | 153 | 95 |
Discussion
When compared with the values found in the "VO2 Max Values For Males" table the VO2 Max calculated in this experiment is considered "superior". This value is a result of the lifestyle which I have adopted and the genetics which formed the basis for my development. My father demonstrated an affinity for athletics when he was younger and as a result proved that a high level of physical fitness is part of the genetic make-up of my family. The other aspect of my life which led to the high VO2 Max value is the activities which I involve myself in. By swimming, running, and playing a wind instrument I have stressed my body in ways which forced it to adapt. By placing that stress on my body I have conditioned it and developed a VO2 Max which is above the average male for my age group. The estimated value which was found is a culmination of my genetics and lifestyle.
Although this activity is designed to provide a VO2 Max value the value which is recorded is only an estimation. True VO2 Max must be measured through the use of an apparatus which analyzes respired air from a subject who is at their point of maximal physical exertion. The method used in this lab relies on predetermined constants and recorded data points to provide a simple estimation. The flaw present in the lab is that the subject is not forced to fully exert themselves. By simply walking around a track maximal exertion is not reached and the true definition of VO2 Max is lost. To remedy this an equation must be developed which requires full exertion by the subject or a simple measurement must be done by a special apparatus. One source of error is the precision of the apparatus being used in the lab. By having instruments which provide more precise data a number which is closer to the true value could be found. This includes a precise heart rate monitor, a stopwatch accurate to a thousandth of a second and a bathroom scale with an easy to read display. Another source of error present in the lab is the instruction which states "Walk a measured 1.6-km distance as fast as you can". The concept of walking as fast as you can is completely subjective. On any given day an individual's ability and drive to walk at peak speed is different. This speed also varies between individuals. To perform a true test in which reliable data is recorded a treadmill is required. By increasing the speed on the treadmill until the subject cannot keep up the true maximum walking speed can be attained. In a true test the subject would not be walking but rather running until their peak speed is reached. A third source of error is the equation used in the calculation of VO2 Max. By using predetermined values which are only accurate to a certain number of decimal places the accuracy of the final answer is reduced. The inherent problem with equations is the precision of the final answer. To remedy this situation and provide a "true" value or a value which is as close to the measured one as possible the inherent error of the equation must be included. An error calculation must be included using a true value or other standard to create an equation which provides accurate results. Another option is to develop an equation comprised of constants derived from an average value of an extremely large sample group. Either method would allow for a more accurate equation.
One component in the equation is the gender factor. Males have approximately six units added to their final answer simply because of their gender. This is due to the difference in physiology between males and females. Males have this value added because in general, the composition of males contains more lean muscle mass. Females tend to have more fat in their body composition then males due to the requirements of child birth. Muscle cells require more energy and as a result they possess a higher mitochondria content. Mitochondria is responsible for processing oxygen and providing the muscles with the energy needed for them to contract. As males have a higher muscle content than females there are more mitochondria processing the oxygen uptaken by the body.
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