1Department of Physiotherapy, Sikkim Manipal College of Physiotherapy, Sikkim
Maximal oxygen consumption by the whole body (vo2 max) is the gold standard measurement of quantifying cardio respiratory capacity or endurance. However, the laboratory measurement of VO2 max is cumbersome and expensive. The only clinical test that is proved to be reliable in VO2 measurement is Queensland step test. But the recent literature states that the functional test 6 minute walk test if performed under strict measures as quoted by American Thoracic Society criteria could yield the reliable VO2 measurement. No literature till date had shown relevance between the functional walk test and clinical step test.
The purpose of the study was to correlate the maximal oxygen consumption i.e. vo2 max obtained from 6 min walk test and 3 min step test. Methods: subjects 26 college students of which (males = 9 and females = 17) of median age 21 (18 – 25 years). Randomly (computer randomization) allocated to one of the stress test either steps or walk test and after a 2 days of washout under strict environment crossed over to the next test. Predictor variables in 6 MWT regression model were age, sex, resting heart rate, resting blood pressure, rate of perceived exertion (RPE) on vas, final heart rate, final blood pressure. Predictor variable in 3minute step test were age, sex, height, body weight, BMI, heart rate.
The variables of each test are described under descriptive analysis and the median VO2 max of step test and the walk test compared with each other using student t test. The plot graphs to illustrate the individual correlations. Results and discussion: the boys VO2 max is better than girls. Their VO2 max correlated well with the BMI. The native students outscore in VO2 max than their aboriginal counterparts. The p value of comparison between VO2 max of step and walk test had not reached the significance.
For, maximal oxygen consumption calculation either of the tests can be used individually. Derivation of VO2 max from one test should not be applied to other since it may lead to erroneous results.
