Tuesday, December 21, 2010

The VO2 Max Challenge

Now I know what a lab rat feels like...
I did a VO2max test today because Jonathan said that it would be a good idea to have a point of reference for the Marathon when it comes to the Ironman: I may find that all the cycling and swimming has a slightly detrimental effect on my running economy and we will be able to measure that and make the necessary adjustments.

The test itself is quite simple on paper but quite hard in practice. It consists of running on a treadmill while your pulse rate, oxygen consumption and carbon dioxide emissions are measured. Ah, and the speed is gradually increased until you can't keep up with the belt and are finally forced to stop. I always finish thinking I could probably have continued just a little longer but then, looking at the results, I usually see that I have hit my maximum heart rate and so that the debate I was having with myself in my head was eventually won by the right "me". In any case, it doesn't make sense to go crazy - I'd only end up getting injured.

Apart from measuring where my aerobic and anaerobic thresholds are (see previous post) and, of course, where my VO2max is, it is very interesting to see whether my running economy is improving. The VO2max is basically a measure of the maximum volume of oxygen I can burn (literally) per minute divided by my mass. The only improvements there seem to come from me losing weight. My running economy, however, has been improving in leaps and bounds. The running economy is defined by how much oxygen consumption (again, divided by mass) is required per velocity at each of the two thresholds - the lower the number, the better. As you can see, my running economy at both thresholds has been getting steadily better. It will be interesting to see the results from the test: I'll post them here once I get them.

In January I'll do the corresponding test on the bike. As you use less muscle mass when you are cycling, the thresholds for the bike are at much lower heart rates than for running. In my case, they are some 30 beats lower which I have trouble accepting. It means that I have to go really easy on the bike in training and it is impossible to go up even the slightest hill without breaching the limit. What makes it particularly hard to accept is that, in running, I notice my breathing pattern changes at each of the two thresholds and I don't really need a pulsemeter to know I am in the right zone; on the bike it feels like I don't get to the lower (aerobic) threshold unless I am competing. I have to decide whether to "have faith" like I did, finally, for my running training. The risk is that I will not advance enough on the bike in training and that I will get frustrated in the race and throw all caution to the wind. Phil Maffetone, the coach of Mark Allen (6 times Ironman World Champion), claims that the thresholds are independent of the sport and can be accurately predicted with a formula. My coach says that he absolutely does not agree with him and, I have to say, I am naturally sceptical of anyone claiming to have a magic formula. But this is just the sort of thing that might pop into my head half way through the bike leg of the Ironman if I am below my desired pace... I have the answer to that one already: thou shalt not worship false idols!

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