In reply to JuneBob:
I ran the Tromsø marathon over the weekend. My goal was to run 3:30, and to avoid stressing my body too much.
I struggled to find my pace at the start because of all the other runners. This was the first time I've taken part in a big race, and I found that I kept clamping on to someone else's pace before realizing it was wrong and overtaking. Then there is the bridge to go over after about 2k, so it wasn't until about 4k that I finally settled in to around 5min/k with a small group, and they looked strong, so I thought it would be a nice bunch to follow along. This went fine until 20k, when the group started to disintegrate. We went back over the bridge and at around 22k I'd lost them all behind me. They'd all suddenly dropped the pace. After that I was on my own. And I did a lot of overtaking. I went from position 219 at 20k to 159 at the finish. It seemed many people had gone out too fast. I suspect many people, myself included, didn't anticipate the effect of the bridge, and particularly the gentle ups at the end. The last 10k was increasingly heavy, and each up was a battle. My pace was around 5:05/k on average, but I know I dropped to 5:50 on some of the inclines, even overtaking some runners walking backwards...
In the end I finished in 3:36:04. I was very happy with that. I never felt particularly out of breath, and my heart rate was comfortable. But the legs were tired. The last 10k I was having to work hard to push them and particularly the final 5k, I lost about 2.5 minutes there. I noticed after the race that sitting down and standing up again wasn't easy!
As for my injury niggles. I had my 40th birthday the weekend before which involved lots of drinking and no training, so I only ran about 5k in the 10 days leading up to the race. And I think it helped as my body had a chance to recover. As such I only had some minor discomfort during the race, and mostly on the balls of my feet from all the pounding.
I still plan to train for a 3hr time in Berlin, but with the expectation that 3:15 is more realistic. I'm going to add more MGP to my long runs to get used to running 4:20/k and do long intervals as suggested. I'll see how it goes!