It's silly, really. I went from a county champion and top 10 in the state in 7th grade to just "good" in 8th grade. 5:17 to 5:03 because instead of running 4 workouts a week I ran 2-3 with a lot of easy runs and no all-out runs. I decided to stop this easy running and "progressive peaking" everybody claims you're supposed to do and opted for the fast, all-out balls to walls running that most high schoolers do. It is cross country season now and I am coming off of an average of 45 mpw over the summer and about 4 consecutive weeks over 50 miles. I have now dropped to about 20 mpw and all-out workouts 3-4 times per week with a meet/time trial every saturday. So far I have beaten my mile PR by a great deal, running a 1600 in 4:46 followed by 4x200s in 31 seconds each I have also improved my 18:10 5k PR to a modest 16:49 and the season has only begun, placing me as top freshman in the state. You might be thinking, "That's burnout work! track work! blasphemy!" Well, I completely disagree! I have been finding runs that used to be difficult much easier for me. It is simple as this: somebody who runs a 400m in 60 seconds finds it a lot easier to run a 2:20 800m than someone who runs a 400m in 65 seconds but completes 800m at the same pace, regardless. I believe that running very hard at the beginning of a season to build your speed up with an aerobic run every 2-3 days is the correct way to do it as your ATP metabolism improves while the rate at which you consume oxygen stays the same as when you ran your peak mileage. You are not improving aerobically, you are maintaining it. You are then cutting your speed down immensely therefore making you a faster runner. Prove me wrong.