I'll add my thoughts, for what weight it carries. I went from 39:31 to 36:33 from reading this thread back last summer when it really exploded. I was stuck around 39 for a long, long time. Maybe around 4-5 years. That was variation between different plans, coaches etc. In fact I probably have spent more on coaching and books than everyone in this thread combined! Not that I mind , I love my hobby.
I started off almost in real time of page 1 of this thread. I read a lot of LRC and thought why not, I seem to run around 39-40 no matter what. I just love 10ks. No idea why. Sucker for pain maybe. They hurt.
Anyway, I have stuck pretty much to sirpoc rules. No lactate meter. Just the paces. The only thing I have changed is when Hard2find came along I switched to his document he provided with those paces. It sounded like himself, sirpoc and a few others perhaps worked on this anyway, from reading between the lines and posts here. Yes I have read everything!
Not a lot happened. For at least 5-6 weeks. Then suddenly I noticed the 3x3ks I had been doing, suddenly got quite a bit faster. Then the same just kept happening, every second or third week. That was about it was as simple as that. Now I was very curious about as to how this on earth was possible. I am pretty much doing the same amount of hours , 6-7, as I was before.
Here is where reading the thread helped. A lot. Well reading it a second time. I plugged all my data into the recommended intervals icu from the past to check past training loads. My CTL or fitness, and this is why you should read the thread, has increased and kept increasing in this time. The overall load of training this way with regards to the way previous coaches had me running, by the metrics, is quite a bit more. This is covered quite a bit somewhere in the middle pages. This is why I think a podcast that has been mentioned would be a great idea, to really summarise it. Anyway, there seems to be a clear relation between increasing of load and then overall performance. I think it's as simple as that. The key is you are doing more, probably aerobically, but the way it is managed, is less taxing on the body. So you are effectively increasing your services capacity, which, at hobby jogger level for the majority of people will lead to better performance. The crazy thing is it feels like you are doing less.
I will say, I follow sirpoc on Strava like others. This dude is a machine. The will power he must have to run the same stuff, day in, day out is remarkable. Seeing it myself is really all that keeps me going, as I can see you will improve. But it really, really is not fun. But the feeling I got from such a huge PB made it all worthwhile. I would rather have that in my pocket than feel like a workout hero like before, then be disappointing on race day.
Anyway, I hope maybe that provides some insight. I am no expert! But I am a massive fan of the thread and absolutely thrilled I found it and it has totally, totally changed the way I think about running . It has been hard to adjust. I didn't even own a smart watch until 2 years ago, so I am very much of the old skool!!