Thursday, January 20, 2011

Bike test

I did the VO2max test on the bike today. You can't really argue with that very straight line showing an almost perfect linear relationship between my pulse rate and the number of watts I was cranking out, which were being steadily increased by Diego, my friendly "torturer". It got to the point where I couldn't go any further just because the weight of my legs was not enough to move the pedals any more; I would have had to get up out of the seat which is probably more like running than cycling (certainly it has little to do with cycling in an Ironman).

I found it very useful to do the test (again) even though my thresholds look as though they will still be where they have been for the past year. This time there was a point in the test when I noticed my breathing pattern change; I glanced at my watch and - lo and behold - it showed 125bpm which is exactly where my aerobic threshold is. The same thing happened at my anaerobic threshold. So this gives me confidence in the thresholds, something that is vitally important, as I have stressed several times already, if I am going to stick to the training and racing plans. What also helps me to accept the 30bpm difference between my cycling and running aerobic thresholds is the fact that I was only able to get to 178bpm while seated; in running (and in general, for that matter) my maximum heart rate is 191. I had previously estimated my maximum heart rate while cycling to be 185bpm, which I registered during a duathlon last year. However, this was going up a b*astard hill standing up on the pedals and cursing loudly.

I still have some doubts over how much the cooling of a 30kp/h wind on the position of the aerobic and anaerobic thresholds. It's clear to me that you can eek out more wattage at a given pulse rate cycling outdoors compared to being on a stifling static bike but this doesn't necessarily mean that the thresholds obtained in the lab are wrong; the question becomes whether you should go by power, by heart rate or by "feel". One thing I do notice, is that when you are out on the road, you are much more distracted and the conditions are constantly changing, such that it becomes very difficult to judge your aerobic zone by feel. By contrast, when I am running, I can usually predict my heart rate to within a beat. I guess this is why so many people by those extraordinarily expensive power meters. I'll stick to my trusty heart rate monitor.

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