CHAPTER 5 DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS This chapter discussed and interpreted the results of the study presented in the previous chapters. It is concluded in three parts. The first part is the discussion of the theoretical and practical implications of the results. The second part reviewed and concluded this study. The third part is recommendations for further study. Discussions This study was conducted on comparison the VO 2 max values from the Astrand-Rhyming Test with VO 2 max values from the YMCA Cycle Ergometer Test, Rockport Fitness Walking Test, Cooper 12 min. Run-Walk Test and Step Test. The results of the study showed that there was no significant different between Astrand-Rhyming Test results and YMCA Cycle Ergometer Test, Rockport Fitness Walking Test and Step Test for both men and women athletes. Methods of measurements of Maximum Oxygen Consumption As the general classification of the measurements of Maximum Oxygen Consumption is widely accepted into directly performed in a laboratory using specialized equipment and indirectly field test using indirect the value of Maximum Oxygen Consumption. Many researchers stated that the most precise assessments of VO 2 max are performed directly in the lab test setting (Bruce 1984; Grant et al., 1999, Larsen et al., 2002). There are different possibilities between types of physical activities for testing aerobic working capacity, such as running or walking on a treadmill, cycle ergometer, rowing ergometer and others. Thus, in this study, the results showed that most of the testing methods results were no significant different with results from Astrand-Rhyming Test, which conducted on different physical activities. However, some of the movement patterns were similar during performing the different testing methods. However, using direct measurement of oxygen consumption are always required some criteria that should be demonstrated so the variable achieved should be considered as the Maximum Oxygen Consumption (Pomerants et al., 2004). Pettersen
56 et al. (2001) agreed that the most widely accepted criterion for achievement of VO 2 max during graded exercise test is plateau in values of VO 2 max as the work rate continues to increase. Moreover, the direct VO 2 max testing in the laboratory must be done individually and monitored closely that often related to both time and time consumption. Therefore, the indirect field testing do not always required special equipment or conditions as in the laboratory, they are simple to administrate and possible to test large numbers at one time. Nevertheless, the field testing are not as precise as laboratory testing, but they are still considered acceptable predictors of VO 2 max (Grant et al., 1999). Also, Beashel and Taylor (1996) stated that Bicycle ergometer tests were found on the principle of extrapolating heart rate to maximum. Perhaps the most widely used of these was the Astrand-Rhyming Test. It required the subject to cycle for six minutes at a known work load. The work load could initially be set according to the conditioning and sex of the subject. Because it was so easy to administer, the Astrand-Rhyming Test and other bicycle ergometer tests are very widely used. Therefore, as the Astrand-Rhyming Test is the most wildly used and accepted in the world, the results indicated the Maximum Oxygen Consumption values were same among Astrand-Rhyming Test and YMCA Cycle Ergometer Test, Rockport Fitness Walking Test and Step Test, whatever the results from comparing between men or women athletes. It could consider the Astrand-Rhyming Test is one of most reliable methods in the indirect testing methods. The advantages and disadvantages of the different methods of the measurements of maximum oxygen consumption In the results, the values of comparing the Astrand-Rhyming Test with Cooper 12 min. Run-Walk Test for men athletes was no significant different, but it was significant different in women athletes. As the different measurements of Maximum Oxygen Consumption have been mentioned in the previous chapters, the advantages and disadvantages of each measurement also obviously affect on the results in this study. The brief summary of them is listed in the following chart (see table 27), which may concisely explain the results of this study as comparing results.
57 Table 27 The advantages and disadvantages of the different methods of the measurements of Maximum Oxygen Consumption Methods of The measurements of VO 2 max Astrand-Rhyming Test YMCA Test Cooper 12 min. Run-Walk Test Advantages 1) Simple test to administer, reasonably accurate and appropriate for ECG monitoring during exercise. 2) Minimal equipment required. 3) Simple to set up and conduct. 1) Cycle ergometer is portable and less expensive; 2) Upper body movement is minimal, which easier to measure exercise heart rate and blood pressure 3) More applicable for measuring cycling performance. It requires no specialized equipment and allows more than one individual to be tested at a time Disadvantages 1) The test score would be influenced by the variability in maximum heart rate in individuals. 2) It would underestimate the fitness of those with a high maximum heart rate, and overestimate fitness with advancing age (as max HR reduces with age). As it is performed on a cycle ergometer, it would favor cyclists. 3) Specialist equipment required. 4) Assistant required administering the test. 1) muscular fatigue may occur prematurely. 2) Fail to reach true maximum cardio output on max cycle test, because 10-15% underestimation of true VO2 max. 3) Blood pressure may be slightly greater compared to treadmill tests, due to longer muscular contractions, and relative intermittent vascular occlusions. 4) Accuracy is based on prediction of MHR. MHR has a wide range of values at any age. 5) Equipment must be well maintained & calibrated. 1) It requires a constant level of motivation, and the smiley pace. 2) The well-defined testing criteria are needed to ensure that it is a submaximal exercise test. 3) The test fails to account for age or body weight, which can influence exercise responses.
58 Table 27 (Continued) Methods of The Measurements of VO 2 max Rockport Fitness Walking Test Step Test Advantages 1) It is applicable to a wide range of individuals. 2) It is easy preparing for the equipment. 1) Minimal equipment required. 2) Simple to set up and conduct. Disadvantages 1) The test and regression equations need to be validated in participants groups. 2) The pace of the walking controlling. 1) The pace of the stepping controlling. 2) The recovering HR should be maintained in 15 seconds before recording data. As Beashel and Taylor (1996) mentioned that the Astrand-Rhyming Test has been widely accepted and used for measuring of Maximum Oxygen Consumption in different purposes and different fields, but as other measurements of VO 2 max the limitations is still no exception in this study. Thus, three of methods measurements results comparing with the result of Astrand-Rhyming Test are no significant differences, but only Cooper 12 min. Run-Walk Test values for women athletes was significant different, which might be consider as the indirectly relation with the disadvantages from the above brief summary. Obviously, some of testing were easy to organize and did not need to much time to conduct. Greenhalgh et al. (2001) mentioned that the limitations raised with subjects` inability to achieve a true VO 2 max based on established criteria, Perhaps the importance of the willingness of participation and appropriate pace of exercise (Shephard, 1984). Thus, in the results, it took more time to participate in the test for Cooper 12 min. Run-Walk Test so that the willingness of the participation could affect on the results. The factors related to measurements of Maximum Oxygen Consumption Since VO 2 max is based on so many different physiological characteristics,
59 Howley et al., (1995) argued that most of the descriptive variable which are statue, body mass and age effect on the VO 2 measurements results. As many potential factor limiting VO 2 max have been discussed for many years, the value of the results are tightly related to all of the factors, which affecting VO 2 are often divided into supply and demand factors, such as diffusion, stroke volume, blood volume during oxygen from the lungs to the mitochondria (Bassett & Howley, 2000). A study by Saltin and Rowell (1980) concluded that it is the deliver of oxygen to active tissues that is the major limiting factor to VO 2 max. In addition, Gollnick et al., (1972) studied that a weak relationship between the body's ability to utilize the available oxygen and VO 2 max. However, the level of absolute maximal oxygen consumption increases with age, growth and maturation. The highest level of VO 2 max in females appears after menarche (Malina & Bouchard, 1991), but Jensen et al., (2001) reported that boys exhibit higher values than girls throughout childhood and adolescence, the VO 2 max of adult females is about 80% of the value achieved by the males. Therefore, the gender differences in the study may also affect the results of the VO 2 max testing methods. Therefore, in the results of Cooper 12 min. Run-Walk Test for women athletes showed that there are many factors may influence the results of the study. There is no much doubt to confirm the result because there are many factors influence on that. Furthermore, there are also limitations due to different methods conducting in the Cooper 12 min. Run-Walk Test, which is no exception. But one of the most important reason to explain the result in this study have to be considered the argument with the most comment physical activities for indirect estimation of aerobic power, which are running and walking. There is still no agreement through, whether actually running or walking should be used and what distance or duration this test should have. However, the common opinion seems to be that running testing is more appropriate for younger subjects (Larsen et al., 2002). Therefore, the speed of the running or walking is another factor to affect the result in Cooper 12 min. Run-Walk Test. The last but not the least, in this study, during conducting all the tests were happened in evening, some participants were reminding pre-season training during the test period, thus, it is difficult to avoid some of the participants to perform the tests when
60 they were fatigue, which could not remain an excellent physical performance. However, as the weather and temperature were changeable in the evening and those factors often are considered influence on working capacity during measurements of Maximum Oxygen Consumption. Ketsingha (n.d.) concluded that temperature should be controlled under 35 Celsius (), otherwise, it would affect on VO2 max values. Nevertheless, during conducting all the tests in this study, the temperatures were recorded under 35 centigrade (). Thus, it might not be considered the affects in the results during each test. The different five testing results have been comprised in this study. It provided the significant meaning for the study which mainly provided the similarity of the most Maximum Oxygen Consumption measurements between the Astrand-Rhyming Test and YMCA Cycle Ergometer Test, Rockport Fitness Walking Test, and Step Test testing methods, which were conducted both for men and women athletes. Therefore, three of the hypothesis was supported by the results of the comparison. Only the results of comparing Astrand-Rhyming Test with Cooper 12 min. Run-Walk Test for women athletes showed different results, which rejected hypothesis 2 in the study. Conclusions The existing data had led to a conclusion that VO 2 max values obtained through YMCA Cycle Ergometer Test, Rockport Fitness Walking Test, Step Test and Cooper 12 min. Run-Walk Test (men) yielded nearest results to the Astrand-Rhyming Test and could be used for field test for VO 2 max when the Astrand-Rhyming Test is not suitable. Recommendations On the basis of the research results, the following recommendations were divided into general recommendations and recommendations for the further study. 1. General recommendations 1.1 After comparing results of VO 2 max value between Astrand-Rhyming Test and YMCA Test, Rockport Fitness Walking Test and Step Test, which were
61 showed that no significant difference. Therefore, each of value from YMCA test, Rockport Fitness Walking Test and Step Test can be used or modified Astrand-Rhyming Test value by other researchers who want to measure Maximum Oxygen Consumption in Exercise Physiology field or related to Sports Science field. 1.2 According to the results of the research, using Astrand-Rhyming Test, YMCA Test, Rockport Fitness Walking Test and Step Test can be used for those people who prefer to test VO2amx but without specialized equipments. Therefore, using any of YMCA Test, Rockport Fitness Walking Test and Step Test may apply to the researchers or trainers who are testing or measuring Maximum Oxygen Consumption. 1.3 According to the results of the research, comparing result of VO 2 max value between Astrand-Rhyming Test and Cooper 12 min. Run-Walk Test, the results was significant difference in women athletes group. Thus, during using Cooper 12 min. Run-Walk Test should consider the gender difference and well prepare and remain participants in similarity of individual paces of running or walking, because the results might be different with the value from Astrand-Rhyming Test. 2. Recommendations for the further study 2.1 In this study, all the participants are university athletics, which from different sports team and performing in different sports training sessions, this findings were supported hypothesis 1,3, and 4 the expectation of hypothesis 2. Further studies should be conducted to design and selected larger number of participants and the different gender. 2.2 According to the study, most three of measurement values are no significant difference with the Astrand-Rhyming Test value, except the value from Cooper 12 min. Run-Walk Test for women athletes group. However, the most simple and easily organized methods could be applied to general use in the future. Thus, further studies should be conducted into the correlation between different VO 2 max measurements methods.