Maximal Ventilatory vs Maximal Predicted Oxygen Uptake
Because of its many clinical applications, the most important concern is the influence of these factors on maximal exercise capacity. Despite the many reports concerning the shortcomings of estimating maximal oxygen uptake, the direct measurement of oxygen uptake using gas exchange techniques remains somewhat limited due to the added cost, time, and personnel required. As mentioned, the precision with which maximal oxygen uptake is predicted is known to be affected by both the protocol and the presence of disease.” One major criticism of the predicted method is that protocols which employ large increments in work result in a less accurate estimation of oxygen uptake. The constant, continuous work increases in the ramp protocol would appear to be 1 method of overcoming these limitations.
The correlation between measured and predicted maximal oxygen uptake using the ramp treadmill (r=0.87) falls in the range of 0.82 to 0.93 observed in previous studies using various incremental protocols among normal subjects (Table 4). 19.34-37 Two points should be considered, however, in comparing the ramp and incremental protocols in this context. First, previous studies have compared measured oxygen uptake with treadmill time, which can differ markedly from predicted oxygen uptake.