Analysis of Difference between the VO2max Values in Field and Laboratory Tests

Purpose of this study is to determine whether there is a difference between the VO2max values in field and laboratory test. 96 students, studying at the Sports Academy of Sports Sciences and Technology of the Pamukkale University, have participated to the study on voluntary basis. While during the field test, the 12-minutes Cooper test has been utilized, as determinant in the laboratory test the Bruce Treadmill test has been used. The data obtained in result of the applied tests were calculated using formula advised for the test. For the statistical analysis of the data, the IBM SPSS (Statistical Package for Social Sciences) 21.0 pack program has been used. In order to define the data distributions, an Identify in Statistics has been performed. For the comparison of two variables on the same group, the Paired Sample t-test has been used. Results have been submitted as average (X) and standard deviation (SS). The value P<0,05 has been found to be significant. Consequently, a statistically significant difference has been determined between the Field test (Cooper) and Laboratory test (Bruce). And this shows that the VO2max value in the applications of the laboratory environment is higher than the VO2max value in the applications of the field test.


Introduction
One of the most important physiological indicators of endurance, Maximal Oxygen Consumption (VO 2 max), refers to the use of O 2 , which reaches a certain maximal level and cannot be further increased by the increase in active muscle mass incorporated into the exhaust [1,2]. It is the maximum amount of oxygen that can be used by a person who participates in large muscle groups and exercises with increasing intensity [3]. It can also be defined as the amount of oxygen the body can use in a minute during maximal intense exercises (L/dk) [4].
The Bruce protocol is a treadmill test protocol that allows the athlete to reach the VO 2 max in a short period of time with the tilt and speed increasing together. It is known that VO 2 max tests should not be continued for more than 8-12 minutes and that the duration of the test period may not reach the VO 2 max of the athletes due to regional fatigue [5,6]. For this reason, the Bruce protocol is considered to be very useful and suitable for detecting true VO 2 max [7,8].
Cooper 12 min test which was developed by Kenneth Cooper from the original Balke [9], is a 15 minute running test. The Cooper test is available in 12 min and 1.5 mile versions. The athlete tries to run the longest distance he can get in 12 minutes. The assistant takes the nearest 100 m note. The correlation between VO 2 max and 12 min run-walk distance was reported as r = 0.90 [10,11,12].
The aim of this study is to determine whether there is a difference in VO 2 max values between field and laboratory tests.

Subjects
A total of 96 students, 45 females and 51 males attending Pamukkale University Sports Sciences and Technology School of Sports, voluntarily participated in the study. The students participating in the study were given explanations about the test to be done by giving information about the research. Athletes participating in the study were signed by reading the informed consent form. When the age was determined, the body length was measured in cm and the body weight was measured in electronic scale and recorded in kg. The cooper test runs the longest distance the athlete can take in 12 minutes. The assistant takes the nearest 100 m note. Correlation between VO 2 max and 12 min running-walk distance is reported as r = 0.90. The equation used to determine aerobic power in the Cooper test is as follows: VO 2 max: Distance traveled (m) -504,9) / 44,73

Exercise Protocol
The implementation of the Bruce protocol was carried out automatically using the Cosmed T 150 (Germany) treadmill, running from the band's memory. The test was carried out at a speed of 2.7 km / h, starting at 10% slope and increasing at a speed and slope every three minutes. The test was continued until the athlete could not continue the test continuation [13]. VO 2 max of the athletes and the formula used for men and women active and sedanter in the calculation part of the Bruce Treadmill application (treadmill test) were calculated indirectly.

Statistical Analysis
IBM SPSS (Statistical Package for the Social Sciences) 22.0 package program was used to analyze the data. Descriptive Statistics were used to determine the distributions of the data. The t-test (Paired Samples t-test) was used to compare two variables on the same group. The results are presented as mean (X) and standard deviation (SD). A value of P <0.05 was considered significant. To determine whether there is any difference in the VO 2 max values between the field and laboratory tests, the averages of the data obtained in the study were determined and whether there was a statistical difference between the variables was determined. When Table 2 was examined, Cooper VO 2 max value was found to be 42,78 and Bruce VO 2 max value was found to be 53,91 (p <0.05), while the mean age of the 96 students was 21,81, the mean height was 170,85 and the weight average was 62,55.

Results
When Table 3 is examined, the significant value is seen as "000" in the comparison between the variables. This indicates a statistically significant difference. That is, there is a significant difference between Cooper VO 2 max value and Bruce VO 2 max value (p <0.05).

Conclusions
As a result of the literature searches made for the purpose of our work, we have supported our work and found many researches that resulted in the opposite direction. Some of those: Michael et al. [16] compared ASU and Bruce protocols in their study. There was no significant difference between the VO 2 max values obtained by estimation and measurement from both tests in the study of 32 age 21.09 ± 2.52 years age group. However, between the two tests, there was a statistically significant difference between the measured VO 2 max values (p <0.04). Jana et al. [17], 18 college players aged 19-23 participated in the study and found a significant relationship between the 9-minute running test and VO 2 max (p <0.05). MacNaughton et al. [18] compared 15-minute running test with 5-minute running test. The study was found to be more effective in predicting the VO 2 max of the 15-minute running test for all age groups. Froelicher et al. [19] compared the Balke Protocol with the Bruce Protocol. 34 sedans with a mean of 36.9 years and 45 athletes with an average of 32 years applied the Balke protocol, 32 sedanter subjects with an average age of 38.2 and 45 athletes with an average age of 34.2 applied the Bruce protocol. In another study conducted by Aydoğmus et al. [20], 20 m shuttle running test was applied before and after training. An increase in the VO 2 max values of the badminton athletes after the shuttle running test, which is an important field test in VO 2 max prediction, has been found. Arslanoglu [21] used a 20 m shuttle run instead of cooper to measure aerobic capacity while studying physical profiles of wrestlers. The same authors observed that the Yo-Yo intermittent test performance was significantly correlated with the time to exhaustion and VO 2 max values at the treadmill test, which led to the assumption that the treadmill exercise tests do not underestimate aerobic performance [22]. The fact that the field tests used to require less cost to laboratory tests and that there is no need for advanced hardware may be the reason for preference in these studies.
In conclusion, a statistically significant difference was found between the field test (Cooper) and the laboratory test (Bruce). This shows that the VO 2 max value in applications performed in the laboratory environment is higher than the VO 2 max value in field applications. It is believed that the results are due to the fact that the VO 2 max value is higher in the laboratory environment and the environmental factors that may affect performance are more minimal.