The article discusses the use of PWC170 test for determining physical working capacity of athletes, in particular the research on athletes who specialize in run on average distances. Currently there are many indicators and methods for monitoring, characterizing the level of physical performance; examines the various points of view on the methods for performing the test, including the divergence of views on the use of prior warm-up or lack thereof, how the job load. Also the possible errors of interpretation that may arise as a result of certain problems. The article contains the results of the study of physical performance of runners 17-18 years old and their physical fitness that allows to compare laboratory data with indicators of operational readiness, obtained directly in the training process. It is shown that based on the results of our test (PWC170 on treadmill) and without having additional indicators that demonstrate a particular functional state of the athlete, it is possible to make erroneous conclusions about the lack of readiness of the past, which in turn would be a gross error in the interpretation of the results. We determined that the direct transfer of the test PWC170 modified by V.L. Karpman on a treadmill, produces notoriously low outputs, requiring different evaluation criteria. The difference of the obtained results, we primarily associate with the characteristic methods of test PWC170, which we used. In connection with this arises the following questions - is it right to compare the indicators PWC170 received on treadmill with indicators PWC170 obtained on the cycle Ergometer, the data which formed the basis of most valuation tables.