Yeah, this is a hard one for me. There are really three ways I can get faster at the 100K/100M distances, and they aren't necessarily mutually exclusive but it's tough to figure out how to do them simultaneously.
1. Get more fit, so that my "easy pace" is faster. That ties into what you're saying, I think. That's going to happen with a good training block, with some intensity mixed in with a steady volume. And a good training block of 18+ weeks would mean no racing, at least not above a 50K.
2. Increase the percentage of the race I'm running vs hiking. But this is tough to work on in training because there is really is no way to "practice" what it's like in the latter stages of a long ultra, whether it's the ability to continue to run the downs (quad conditioning) or the flats (just pain and tired). There is a physical component to it, whether you want to call it strength or muscular endurance, but it's probably mostly mental. In training I think the closest you can get is back-to-back long runs, forcing yourself on that second day to run on tired legs. I talked to my pacer Surf about that during those last 10 miles at San Diego, as while he didn't have a good day he has run a handful of sub-24 hour 100Ms. He said he gets so used to the pain of running on tired legs in training on that second long run that it just doesn't bother him anymore and he can do it indefinitely during the race. I need to do that more. But even that is nothing like actually experiencing mile 58 or 94, and I know I've gotten better at running more, and later, the more races I've done.
3. Execute the "non-running" parts of the race. Nutrition, hydration, blisters, electrolyte balance, and managing aid stations. Again, you can "practice" your nutrition in training, but finding something that I works for even 5-6 hours doesn't mean it's going to work at 15+ hours. The aid station one is a tricky one for me. I spent a ton of time during San Diego in aid stations, even though I was doing something the whole time, not just sitting and resting. Eating, drinking, filling everything with ice, refilling my pack, cleaning my feet and re-lubing, dealing with blisters, etc. And doing those things leads to fewer problems out on the course, and I think overall I executed SD pretty well. So if I cut 30-40 minutes off my aid station time that's great, but does it end up costing me an hour on the course due to other issues getting worse? And oh yeah, every race is different because of the conditions, so what works once may not work the next time.
In the end, it's a constant internal battle for me. I know I could train differently (more flats to work on turnover, more intensity, etc), and that I could get more fit, and that would likely make race day an even better experience for me. But I don't love running. I love being outside, on the trails. I love the community at races. I love the planning and problem solving that are such a huge part of a 100M. I love the community and the volunteers and the aid stations. I love the sunset and the sunrise when I'm out on the trails. And most of all I love that feeling at the finish, a feeling you can only get on race day.
