Prediction Of Maximal Oxygen Uptake From Ratings Of Perceived Exertion In The Young Obese Women During A Sub-maximal Intensity Exercise

The incidence of obesity and related metabolic disorders show an upward trend this years. And obesity and related metabolic are one of the important factors that become a danger to public health, which have important relationship with a variety of disease, such as diabetes, high cholesterol, heart head blood-vessel. Compared with men, obesity has much more apparent effect on women because of different physical characteristics, such as higher body fat, reproduction and so on. Therefore, losing weight is much more important on women than men. It is well known that appropriate exercise is the most effective way to lose weight.Regular exercise can prevent effectively obesity and make a difference on body fat. How to control the exercise intensity is the core element of measuring the effect of exercise prescription. Of all the indexes of reflecting the exercise intensity, VO2max(Maximal oxygen intake) is the most important and normal, which can provide a way to formulate and implement scientifically exercise prescription according to different subject. Testing the VO2 max directly require expensive equipment and complicate process, which become an obstacle on introducing VO2 max during the mass. However, it is pretty convenient to measure VO2 max indirectly. There are much more different ways to measure the VO2 max indirectly,except prediction based on Ratings of perceived exertion.Purposes: Explore a suitable method of predicting VO2 max based on RPE on obese young women; Provide an new exercise thought on losing weight scientifically for the obese young women.Methods:(1) 66 obese young women(body fat percentage≧30%) were recruited in university to attend the research. Of all 66 subjects, 46 women were choice randomly to speculate the equation and the rest women to test the equation. In the tests, power cycling was used to increase the load, which is called Graded Exercise Test(GXT). The data(VO2, HR and RPE) from the last 10 s in each circle were used to speculate the equation.(2) Prediction of equation: Record directly the data(HR and RPE)on RPE9,RPE-13,RPE-15 and RPE-17 in the power cycling test; Establish the corresponding liner equation according independent variables(RPE and HR) and dependent variable(VO2); Findequation by the data and VO2 = a + b ×(RPE) or VO2 = A + B×(HR); Predict VO2 max according two different equations and independent variables RPE19, RPE20 and(220-age),(208-0.7 x age) respectively.(3)Measure the validation of equations: analysis comparatively with the existing methods(Astrand-Ryhming and step by step experiment method).Results:(1) Through T test, the predictable data according the RPE9-17(RPE20), The HR9-13(220-age) and HR9-13(208-0.7 x age)(28.77±4.60ml/kg/min,31.25±8.16ml/kg/min 、 30.04±7.61ml/kg/min) have no statistical difference with the real data(28.68±2.79ml/kg/min)(P>0.05). The statistics from other methods(RPE9-13(RPE19),RPE9-13(RPE20), RPE9-15(RPE19),15(RPE20), RPE9-17(RPE19), HR9-15(220- age),HR9-15(208-0.7 x age), HR9-17(220- age), HR9-17(208-0.7 x age) have significant difference with the real data(P < 0.05). The results indicate that they are accurate comparatively to predict VO2 max according to RPE9-17(RPE20), HR9-13(220- age),HR9-13(208-0.7 x age).(2) Through simple correlation analysis, the results show that the data from RPE9-17(RPE20) are highly correlated with the real data, and it is significant difference between them(r=0.809, P < 0.01). The data from other methods(RPE9-13(RPE19), RPE9-13(RPE20),RPE9-15(RPE19), RPE9-15(RPE20), RPE9-17(RPE19), HR9-13(220- age), HR9-13(208-0.7 x age), HR9- 15(220- age), HR9-15(208-0.7 x age), HR9-17(220- age),HR9-17(208-0.7 x age) was significantly low related with the real data( r<0.8, P < 0.01). The results indicate that RPE9-17(RPE20) prediction method is much more accurate.(3)Through the Bland–Altman, the predictable data from RPE9-17(RPE20) and HR9-13(208-0.7 x age) have good consistency with the real data, and the mean of actual difference and the mean of theory difference are approachable(0.660). predict VO2 max value also has a better consistency with test values directly, the actual difference between the mean value and the theory of differential mean value were close to(0.623). The actual difference between the mean value and the theory of differential mean value from other methods(RPE9-13(RPE19),RPE9-13(RPE20), RPE9-15(RPE19), RPE9-15(RPE20), RPE9-17(RPE19), HR9-13(220-age), HR9-15(220- age), HR9-15(208-0.7 x age), HR9-17(220-age), HR9-17(208-0.7 x age)are pretty different. The results indicate that The results indicate that RPE9-17(RPE20)prediction method is much more accurate.(4)The data from Astrand-Ryhming method, step by step experiment method, RPE9-17(RPE20) method have good consistency with the real data. However, the data according to Astrand – Ryhming has statistical difference with the real data through T test(P < 0.01). The data from step by step experiment method, RPE9-17(RPE20) method has no statistical difference with the real data through T test(P > 0.05). The predictable data from RPE9-17(RPE20) method has the highest simple correlation coefficient, significant statistical difference(r = 0.853, P < 0.01). The results show that RPE9-17(RPE20) method is much more accurate compared with other methods.Conclusion: Compared with Astrand- Ryhming and step by step experiment method RPE9-17(RPE20) method can predict well VO2 max on obese young women.