My goal is sub-3 in a few years; I'm nowhere near that right now, but it was an interesting read. Is Fitzgerald a worthy source?
His takeaways:
1) 40-50 miles per week consistently, as a minimum.
2) Consistent long runs with some at MP, not just base pace.
3) Equivalent fast races (5k to half).
He also has speed training tips and makes distinctions between various TYPES of speed:
https://strengthrunning.com/2017/12/speed-training-fast-running-speed/Acceleration is how quickly you can go from a position of rest to maximal velocity. In other words, it’s how fast you can get to top speed from a standing position. It’s a good measure of power.
Maximal velocity is your top speed – the absolute fastest that you can run. If you try to sprint at 100% effort and reach your “top-end” speed, then you’re at maximal velocity.
Speed-endurance is how long you can hold your maximal velocity before slowing down. Most runners can only maintain their top-end speed for about 40 meters (this is normal!).