u/cettu

I'm struggling to find my running fitness. About 1.5 years ago I was in decent shape with a 18:48 5k, 1:26 half marathon, and 3:06 full marathon. Now I'm training for a marathon and had big hopes for breaking 3h.

However, I've fallen far from my last years fitness. The main reason is quite obviously a big reduction in both training volume and quality last year. I had other priorities and focused more on easy daily movement rather than challenging myself. I ran a 5k in October with a shockingly bad result (20:01). I did another one in January with the exact same result. That showed that the one bad race wasn't a fluke but I've really lost a lot of fitness.

As I wanted to run a marathon mid-May, my plan was to quickly ramp up volume to get a solid base in March and then try to sharpen it in April-May. So I ramped up my mileage from ~40 km/week to 100 km/week in March (I've done fast mileage increases before and I know body body handles it well without injuries, maybe due to my background as a competitive runner and many 4000-km years in the past). So that went well. I then added a few hard threshold sessions in early April and ran a half marathon today (April 19). My goal was to sit at marathon goal pace (4:15) for the first 10k and then pick it up. However, the race was a flop. I only ran 1:32:45 (4:23 pace), so obviously my 3h marathon dream is unrealistic.

Trying to analyze why, I think I'm missing a top gear in my system. My average HR was only 158 during the race with practically no drift. Usually I can sit at around 162-165 for a half and ramp it up to 175 for the last 1-2 km. So I have created a diesel engine with a very modest top speed. I've always done better at all distances (incl. 800 and 1500m) if I approach them from shorter events rather than trying to build distance->specificity, and I think it might still apply for the marathon. It certainly worked for my 1:26 half 18 months ago, since I did a very had 10-day block of daily high-intensity about two weeks before the race. It made me tired of course, even over-reached, but I got a good supercompensation out of it and actually ran a PB by 1 min and this was at mild altitude.

I'm thinking that after 20+ years of pretty consistent endurance training, I've stopped responding to "normal" reasonable training since that is just my baseline. I'm also not getting any younger and will turn 40 this year. I think my changes of breaking 3h for the marathon as a middle-aged woman are wearing thin unless I try something a little more radical.

So I'm looking for some crazier than average advice. BTW, my VO2max has always been solid: I was sitting at 62-63 at my best, and even last year I recorded 60 mL/kg/min. But it fluctuates a lot based on what I do. I get frequent testing since I'm an exercise physiologist. Not doing any intensity gradually drops my VO2max to 52-54. Right now I'm sitting at ~56 (measured on the bike, not treadmill), and it's realistically not high enough for a 3h marathon. I know I need to bump it up by 5-10% to have a chance.

My question is: How would you a) salvage this marathon I have coming up on May 17th, and b) (since I won't break 3h) revamp my training enough to build up my engine once more to try and hit good times for another couple of years before I give up and take up knitting?