Validity of Queen's College Step Test for estimation of maximum oxygen uptake in female students

Maximum oxygen uptake (VO(2) max) is internationally accepted parameter to evaluate the cardiorespiratory fitness. But determination of VO(2)max is restricted within well equipped laboratory because of its exhausting, hazardous and complicated experimental protocol. Various attempts have been made to enumerate indirect and easy protocols for prediction of VO(2)max but such record is unavailable in Indian women. The present study was conducted to validate the applicability of Queen's College Step Test (QCT) for indirectly estimating the maximum oxygen uptake in female sedentary university students.

Forty sedentary female university students of same socio-economic background were recruited by simple random sampling from University of Calcutta, Kolkata. VO(2)max of each participant was determined by direct procedure and indirect QCT method with a gap of four days in between the tests. Direct estimation of VO(2)max comprised incremental bicycle exercise followed by expired gas analysis by Scholander micro-gas analyzer whereas VO(2)max was indirectly predicted by standard protocol of QCT.

The difference between the mean VO(2)max values directly measured and indirectly predicted (PVO(2)max) was statistically significant (P<0.001). Limit of agreement analysis revealed poor confidence level for application of current method of QCT in the studied population. VO(2)max value exhibited significant correlation (r = -0.83, P<0.001) with QCT pulse rate. For precise and reliable estimation of VO(2)max in the studied population a new equation was computed.

Our results suggest that QCT in its original form cannot be applied due to its poor agreement with the direct method but can be applied with the modified equation in this population to evaluate maximum oxygen uptake, especially when large numbers of participants are to be tested in absence of a well equipped laboratory.