Physiology Lab Report Final PDF

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Physiology Lab Report Final...

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18th April 2017

Introduction to Exercise Physiology SES08106

Differences in VO2max Test Results with Relation to Gender

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Introduction This report was created to compare data collected in two different VO2max tests and to analyse these results in relation to gender. The rationale of this study was to find out if there was a difference in VO2max results between male and female. Two separate tests were carried out with twenty-one individuals over a three-week period. The first set of tests took place on a static exercise bike while the second set of tests took place on a treadmill. VO2max can be described as the maximum amount of oxygen that someone can use whilst performing intense exercise (Quinn, 2017). This means that the VO2max test is a method of measuring the athlete’s maximum intake of oxygen. There are many studies which have previously been carried out on VO2max testing because it is a very common experiment used in sport science, however there are only a few experiments that have been created which look at the gender differences in VO2max results. (Kline et al, 1987) Found in a study which they were considering gender, age and body weight with VO2max that on average, the males whom were involved in the study had a higher VO2max than the females whom were involved. Another more recent experiment analysed the age and gender differences in VO2max in Swedish obese children. The experiment found a similar result, which suggests that overall males have a higher VO2max than females (Berndtsson et al, 2007). These are two examples that have similar conclusions to each other much like the other research that has been completed in these certain fields. There were no articles discovered that conclude after their research that females on average had a higher VO2max than males. To create the hypothesis there had to be some discussion as to what results were expected. Before looking at the literature the anticipated result was that males would

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have a greater VO2max as they tend to have greater lung capacity. The hypothesis was then created from this theory and through researching, that males will show higher results on average compared to females on both the exercise bike and the treadmill due to the males having a larger lung capacity. By finding the two previously mentioned journal experiments it helped to support the hypothesis for this report. After creating the study's hypothesis, the null hypothesis was then created which is that there will be no difference between male and female participant's VO2max test results.

Methods Subjects 21 exercise physiology students from Edinburgh Napier University were included in this study (N=21). The subjects whom were included in the study consisted of male (n=14) and female (n=7) students. The subjects ranged from eighteen years to thirty-three years (mean age of 21 years) and each subject participating had a different physical ability. Each of the participants that did take art in the study, volunteered and could withdraw from the study at any time. Every participant completed a pre-activity readiness questionnaire in which they had to declare any underlying health conditions or any other contraindications that would cause the participant to be withdrawn from the study. The height, weight and blood pressure was also measured by other members of the class and recorded on a spreadsheet beside their initials.

Procedure Before the experiment was started, all subjects were given a questionnaire asking if they had any health conditions that should be made aware and a signature was required to

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provide consent from the subject. After this, each subject's height, weight and blood pressure were measured and recorded. Next the subjects were then given every piece of information on how the experiment was going to carried out. They were informed that they were expected to give 100% effort to the test and that they could stop whenever they felt they had worked to their maximum potential. A detailed run through of the experiment was then described to the subjects which entailed that they were required to cycle on a static bike (Trek 1.2, USA), and then in two weeks, run on a treadmill (Woodway Ergo ELF-55, Germany) with a mask covering their nasal and oral passages that was attached to a CPX machine (Jaeger CPX, Germany) to allow constant monitoring of the subject’s VO2 output. Once all the information was given to the subjects, a heart rate monitor (Polar FS1 Heart Rate Monitor, Finland) was fitted to the subjects’ chest which displayed results on a watch to enable constant monitoring throughout the test. The subjects were also fitted with a mask covering their oral and nasal passage. The mask was fitted firmly to the subjects face and tested to ensure that it was completely air tight. The mask was linked to a CPX (Jaeger CPX, Germany) which constantly measured the Co2 output of the subject during the test. During the tests, there was an assigned person to keep track of time using a stopwatch to ensure accurate recording. When measuring the subjects’ VO2max on a treadmill, the participant walked at a speed of 1.7 miles per hour (mph) for three minutes at a ten percent incline. Every minute the subject would indicate their rate of perceived exertion (RPE) by rating their efforts on a scale of 1-15, one being no exertion at all and fifteen being maximum exertion. Every two minutes the testers measured and recorded the subjects heart rate and VO2 output. In the second stage (4-6 minutes) of the treadmill VO2 max test the gradient was increased by two percent and the speed was increased to 2.5mph. In each stage of the

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test, the speed increased by 0.9 mph and the incline increased by two percent. This process was continued until the subjects were exhausted and felt they could no longer continue. When measuring the subjects’ VO2max on a static bike, female subjects started at an initial power output of fifty watts while male subjects started at one hundred watts. At one minute intervals, the subject would be asked to point to a number on the RPE scale to enable the testers to gain an insight of how the participant was feeling. At two minute intervals, the subject’s heart rate and VO2 output was recorded and the cycling power output was increased by twenty-five watts for female and fifty watts for males. The test continued until the subjects were exhausted and felt they could no longer continue, at which point the last reading was recorded and the participants would drop all resistance and cool down gently.

Data Analysis All pre and post tests were entered into an excel document containing all 21 of the subjects’ results. The results that were recorded were: • Gender • Age • Height • Weight • VO2max on the treadmill • VO2max on the exercise bike The first pieces of recording that were put in were the gender, age, height and weight which were all completed before the experiment took place. All of these were used in order to be able to use the information from the VO2max test as a comparison between

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each individual’s results, and although the one this specific report was most focused on was gender, it was still useful to record the other factors as they could be used if there was to be another hypothesis created for another report which could have considered, for example, if height can affect VO2max results. The next piece of information recorded was the VO2max on an exercise bike because this was the first test completed. The information was gathered from the test and added to the excel document. Finally, a couple of weeks later the exact same happened with the VO2max treadmill results. After all this the information was ready and it was now there to be resulted.

Results For these results, there had to be dependent variable decided. A dependent variable can be described as the specific variable(s) that is/are being tested during an experiment (Helmenstine, 2017). The dependent variable always relies on the independent variable. For this experiment, the independent variable is the VO2max test, and the dependent variable is the two genders, male and female, as this is what the experiment aims to either find a difference between or find no difference. Table 1. Independent Sample t-test. (From left to right) test statistic of Levene’s test, pvalue corresponding to this test statistic (3.559), computed test statistic, degrees of freedom, p-value corresponding to the given test statistic and degrees of freedom, difference between the sample means, standard error.

Table 1. Shows an independent sample t-test calculated on SPSS Statistics for

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treadmill VO2max test data. The key 't' shows computed test statistic of the mean difference between the two variables selected. These two variables were the two genders, male and female. This test statistic was calculated by subtracting the mean value of the female VO2max results from the mean value of the male results. The result of this calculation was 3.409. Table 2. Independent Sample t-test. (From left to right) test statistic of Levene’s test, p-value corresponding to this test statistic (3.296), computed test statistic, degrees of freedom, p-value corresponding to the given test statistic and degrees of freedom, difference between the sample means, standard error.

Table 2. Shows an independent sample T test which was calculated on SPSS Statistics for static bike VO2max test data. They key ’t’ shows computed test statistic of the mean difference between the two selected variables. These two variables were the two genders, male and female. This test statistic was calculated by subtracting the mean value of the female VO2max results from the mean value of the male results. The result of this calculation, as seen in table is 3.79.

Table 3. Paired Sample t-test. (From left to right) The pair of variables being tested, mean, standard deviation, standard error, the paired T test statistic, the degrees of freedom, the p-value corresponding to the given test statistic t.

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Table 3. Shows a paired sample t-test which was calculated on SPSS Statistics. The table compares the mean data collected from the treadmill VO2max test and the static bike VO2max test. The mean statistic was calculated by subtracting the treadmill results from the bike results, giving a total of 1.25714 (±5.567191) as stated in the table above.

Discussion After the experiment was completed and the results were finalised, it was clear that the initial hypothesis for this study was supported by the results found in the laboratory. It was found that on average, the male subjects scored higher on the VO2max test on both the bike and the treadmill compared to the female subjects. Evidence suggests that gender has a direct impact on lung development and human physiology (Carey et al., 2007). This impact of greater lung growth and development in the male gender correlates with the results found in previous studies and also with the research carried out in this study which suggests the VO2max test result of the male gender is significantly higher than the VO2max test result of the female gender. This investigation has supported information which has been previously found by Kline et al (1987) and Berndtsson et al (2007) as previously mentioned in the introduction. These are not the only previous studies that have had the same results. Kohrt et al (1991) Found in a study of 60-71 year olds that, on average, males improved their VO2max more than females over a testing period, further supporting the findings from this experiment. Some studies have not found the same results as this experiment, however. In a study which aimed to see if gender had an effect on the relationship of time limit at

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100% VO2max with other bioenergetic characteristics (Billat et al, 1996). This study found that gender had no impact at all on the results. However, Billat et al (1996)'s study was the only one found which had the results that disagreed with this experiment, meaning that the results for this report correlated with most previous studies.

This experiment primarily investigated the differences in results of VO2max testing between both genders, male and female. The results found in this experiment indicate that the male gender in this sample group have a larger mean VO2max test result than the female gender. The results also found through comparing VO2max results in a paired sample t test, that the sample group used in this experiment showed a higher mean result of 1.257414 (±5.567191) while participating in a VO2max test on a treadmill than they did in on the static bike. This study indicates that previous research is correct, however the study would give more accurate results if the sample group used was of a larger quantity and included an equal number of each gender. To gain more accurate proof that the predicted hypothesis is correct, more research would be needed. Further studies on this topic could provide a more accurate outcome in the differences of results between gender in VO2 max testing if, the sample group was larger, the age spread was wider and the subjects whom took part in the study had familiarised more with the process of VO2max testing. To conclude, this experiment has proven to be a success as a whole as it managed to show that the initial hypothesis created was the correct one. Although there were some things that could be improved with the set up and delivery of the experiment, the outcome still managed to prove the hypotheses that was predicted in the study. If

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this experiment was to be completed again, one thing that should be changed is there should be the same number of males and females to give a more reliable, fair and accurate result. Word Count: 2,261

References Verywell, Elizabeth Quinn. (2017). What is VO2max and how is it measured in athletes. Retrieved 13th March 2017, from https://www.verywell.com/what-is-vo2max-3120097

Kline, G.M., Porcari, J.P., Hintermeister, R., Freedson, P.S., Ward, A., McCarron, R.F., and Ross, J. (1987). Estimation of VO2max from a one-mile track walk, gender, age, and body weight. Medicine and Science in Sports and Exercise, 19 (3).

Berndtsson, G., Mattsson, E., Marcus, C., and Evers Larsson, U. (2007). Age and gender differences in VO2max in Swedish obese children and adolescents. ACTA PÆDIATRICA, 96 (4), 567-571. ThoughtCo./Anne Marie Helmenstine. (2017). Dependent Variable Definition. Retrieved 23rd March 2017, from https://www.thoughtco.com/definition-ofdependent-variable-604998 Carey , MA., Card , JW., Voltz , JW., Arbes, SJ., Gemolec, DR., Korach, KS., and Zeldin, DC. (2007). t's all about sex: male-female differences in lung development and disease. US National Library of Medicine , 18 (8), 308-313. Kohrt, W. M.., Malley, M. T.., Coggan, A. R.., Spina, R. J.., Ogawa, T.., Ehsani, A. A.., Bourey, R. E.., Martin 3rd, W. H.., and Holloszy, J. O.. (1991). Effects of gender, age, and fitness level on response of VO2max to training in 60-71 yr olds . Journal of Applied Physiology, 71 (5), 2004-2011.

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Billat, V., Belliot, J., Jan, J., Rochcongar, P., and Carre, F. (1996). Gender effect on the relationship of time limit at 100% VO2max with other bioenergetic characteristics.. Medicine & Science in Sports & Exercise, 28 (8), 1049-55.

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