I'm not an x-tree nor an x-hoosier but thought I'd chime in (as usual) anyway. Let's say you take two treadmill tests 4 weeks apart on Monday. Let's also say you race two times during those same 4 weeks, on the Saturday after the treadmill tests. Let's say during the first test you score a Vo2max of 70 ml/kg and a ventilatory threshold of 72% and during the first race you run 25:00. Now, you do your damnest to improve your Vo2max doing workouts specifically geared toward Vo2max and to improve your threshold doing workouts specifically geared toward improving that number. During the 4th week you test again, this time you hit 74 ml/kg and 75%, but running a race on the same course you run slower...25:25. Why did you run slower despite improve physiological numbers. Why? Because the only numbers that matter are time and place. You have to learn to train to improve time and place and once you make that a priority then the other physiological numbers will improve. Specifically speaking, during those 4 weeks you did NOTHING to improve actual race fitness and race economy. Treadmill tests teach you nothing that you can not otherwise learn from racing. The time and energy you spend doing the tests can be used better by either running a race or a repeatable workout (ie: run 4xmile once every month, compare times).