I'm interested in this too. I know from 23 and me that my body does not create the protien that produces fast twitch muscles. But I've always been much better at the 800 and 1500 than longer distances. Pbs are 53 400m, 1:55 800m, 2:28 1k and 4:01. Best xc time was a 25:56 8k and that was a big jump for me
I've responded well to high milage with fast intervals thrown in but I would always struggle with LT and V02 intervals. Also during 200 repeats with other 800 runners I'd always play catch up off the start. I could do 200 intervals at 25 seconds but it would take me 100 meters to get up to speed.
I'd really like to hear what others without fast twitch do. Especially to help finish strong in races. In the 800 I would never be able to finish strong I could just fight through the lactic acid. 55-60 was my preferred splits in the 800.
I don't even run anymore but this topic caught my eye.