Post Marathon analysis

You can see from the first graph the difference between the two Marathons I have run. What is striking is that the line representing the Amsterdam Matathon from 2008 is very similar to the line representing San Sebastian, just shifted left by about 15 kilometers! It looks like I was using my anaerobic engine from the start of Amsterdam - probably a combination of starting too hard and not having done enough aerobic training prior to the race.

In the second graph, you can see the very clear trend that I was running faster and faster throughout the whole race - I wasn't even aware of this until after the 35km mark, when I decided that I felt strong enough to push on to the finish line. I think I could have started off a bit faster but, who's to say that I wouldn't have blown up. Something to try next time now that I finally have a Marathon I can be proud of under my belt... Certainly I was trying too hard to be below Jonathan's prescribed heart rate: as there is always some "noise" due to slight inclines, wind, etc., perhaps I should have allowed it to go a bit over the limit knowing that there would be other stretches that would compensate.

What is really interesting (well, to me, anyway) is the third graph. I had thought that the calorie counter in my watch would have a fairly simple algorithm that would correlate calorie expenditure to heart rate but I was surprised to see that I was burning as many calories per kilometer at the beginning of the race as at the end. This is partly due to the fact that, at the beginning, my heart rate was low but I was taking more time to cover the ground; at the end, my heart rate was much higher but I was running faster. Even correcting for this, it turns out that my watch has something a lot more sophisticated under the hood. The third graph compares the number of calories I was supposedly burning per kilometer with the number of heart beats I was above or below Jonathan's prescription. There definitely appears to be a relation between the two - maybe something for Jonathan to look into? It would certainly be a lot easier to maintain my calorie burn at 63kcal/km, say, rather than having to scribble the particular heart rates for each kilometer on the back of my hand / watch.

As for how I feel today, I really don't feel bad at all. My weight is back to normal (although I did break the 8% body fat barrier!). My legs are a bit stiff, mainly in the muscles that I didn't concentrate on in my weight training, interestingly enough, like the groin, glutes and hip flexors. Now I have a little holiday from serious training, to allow my body to rebuild itself after its little ordeal. Its definitely a good moment to get back in the swimming pool and see if I can get some halfway decent technique...