I have seen many calculators tell me that my ideal training pace for being in 17 min 5k shape is around 7 min/mile easy, 6:30/mile marathon, and 5:55-6:00 lactate threshold. Now, the predicted race paces are accurate. I could probably run 2:50 for a marathon, but why the hell would I as a high schooler? Also, I know of many people who run my 5k pace for a marathon and their easy runs aren't even 7 mins/mile. My training paces are as listed:
Easy: 7:45-9:00 (although I very rarely run below 8:00 and an average easy run will be at 8:30/mile)
Interval pace: 12x400s are done @70-75, 10x800 @2:40, 5x1k @3:20.
Many calculators and coaches will tell me 4:50 interval pace is sufficient but I wholly disagree.
Lactate threshold: Again, kind of a weird one. Cannot push yourself if you're not feeling it and hit paces that you cannot hold. 20 min tempos @6:00, 40 min tempos @6:20. Pretty simple.
What to take away from this: Range is the most important thing in developing, and you can't just maintain the same easy paces and LT paces as the season progresses. If you are looking to get better, whether you're developing into an adult and looking to be competitive, or you're past your peak, as you get close to a race you should be cutting miles and cutting pace all-round. As I am getting ready to break 17 I'm doing this:
Worked up from 25-30 mpw and am focusing on getting stronger. Made easy runs easy, went from 6:50-7:30 for easy runs to 8:30s. Went from 25 mpw to 45-50. I plan on peaking at 60-70 mpw with 2 workouts a week, one 20 min tempo @6:00 and one interval workout. As the season progresses to where I will consistently need to run 16:30-17:00 to be competitive, I will drop easy runs down to 7:00, tempo runs down to 5:50, and my mileage will go to 35-40 and I'll run 3-4 workouts a week .