This test reliability really does depend on the students and the effort that they put into it. If students give the same effort every time that they perform this test then yes the results will be reliable. However if the students give 110% one time and then only give 50 or 75% the next time then the results will not be reliable. I controlled reliabilty by motivating students to set goals and try and beat their previous scores. I also try to maintain comfortable conditions for the test so that the students are more willing to perform the test.
According to NASPE and the Cooper’s Institute the test is a valid measure of cardiovascular endurance. It has been proven to provide an accurate estimate of VO2max. This test is intended for students age 13 and older since it hasn’t been validated with younger samples.