A lot of it has to do with the volume of work you're currently at for each pace. Ex, my guys yesterday did a 4 mile tempo at MP, 5 min + 8 x 400 at 3k/5k w/ 200 jog. Currently a 100% workout for them would be roughly 8-10 miles at MP and roughly 6,000m at 3k/5k. So the workout above is roughly 50% of a 100% workout at MP and roughly 50% at 3k/5k, you generally want to avoid doing workouts above 100%. The idea is to figure out the volume for each pace (400, 800, 1500, 3k, 5k, 10k, 1/2m, MP, 80%). For stuff at 400m pace, the max volume we usually do is 800m, maybe 1200m and we have athletes take as much time as they like between, so 2 x 400 all out followed by 10-15 min is OK.
If you can find it, Running Trax or Purdy Tables helps a ton, it will give you a value for a race performance and corresponding number of reps at each distance and various speeds. It helps you not overdo things. But back to your question, when it comes to intervals at 800m pace or faster, I've had better luck not putting a tempo in front of them. It's really stressful. We don't do a lot of stuff at 400m pace and when we do, it's it's own session, so 2-3 x 400 at best effort, maybe 2 x 600 at best effort. Trying to run that fast when fatigued I haven't had much success with. Instead do the 4 x 100 before a tempo. We do accelerations which includes portion at 400m pace as part of our warmup routine with quite a bit of success.
400m speedwork when you're warm and fresh tends to work better, one of the things you're focusing on when running that fast is having good form which is difficult when fatigued which a tempo run beforehand would do.
If you wanted to do something fast after a tempo, hill reps or perhaps 200's at 1500 pace w/ 200 jog after works well.
Good luck, let me know if you have more questions.
Thank you so much Joe, I have one more question. Do you still do the speed development days that you wrote about in the Middle Distance Guide? If so, how do you plan it out in the week, and is it the same as listed in the guide?
Yeah, the thing is you'd ideally do the top end speed after a shorter run. So a week week something like this:
Sun: Long run easy
Mon: Speed maintenance day: Decent 30-45 min run followed by faster work. This is where you'd throw in your 4 x 100 efforts.
Tues: Easier run
Wed: 1500-3k work
Thur: Mid week longer run
Fri: Recovery day. Day off or 1-2 super easy 30-40 min runs
Sat: Tempo run or longer work at 5k-10k pace
Let me know if you have additional questions, happy to address the.