Base Mileage Thoughts

Maybe it really isn't appropriate to title this post "Base Mileage Thoughts", but it's close enough.

As has happened before, a lot of training ideas are starting to converge for me. It's funny how sometimes you really need to have a sufficient knowledge base to understand what someone is trying to explain. A lot of times, I feel like I need to take a piece from this and a piece from that before a bigger idea finally makes sense.

So, one of the pieces of this puzzle was an article that Ashwin had linked to. I think this article is, by the way, nearly impossible to understand without some significant understanding of cycling training principles.

Another piece of the puzzle was my frustration, or lack of understanding, about why long rides are necessary for mountain bike and cyclocross. In lots of books you read (and in my club), people are suggesting you do these 4-6 hour rides. For road racing, I can understand this, as the race distances are approaching this range. But, to ride 4-6 hours for a 2 hour mountain bike race, or a 1 hour cross race? I don't get it, it's always seemed like overkill to me.

The last piece is my reading of several different books and websites about higher intensity training.

I want to avoid turning this into a full program discussion, but the above sources have helped me answer the question I have. How long do my long rides have to be, and how many do I need to do? I think the answer is "not that long and not that many".

One of the key ideas from the Willet article was to match your "fill rides" (long rides) with the expected energy expended during the race (energy = power x time). Doing more than this is not really useful; it increases your fatigue level with little benefit. I made a little chart of energy burned as a function of intensity (% CP30) and time (hrs). Here's the key thing to notice: increasing time increases energy expended much faster than increasing intensity. (Sorry, I couldn't figure out how to make the image bigger in Blogger.)

Let's say you can do a 1hr 'cross race at 95% of your CP30 power (maybe this intensity is too high, I don't know). If you have a CP30 power of 268W (which I do), you burn 917kJ. So, if you want to do an endurance ride at 65% of CP30 (not working too hard), you'd only have to ride for 1.5 hours to roughly match the energy expended in the 'cross race.

You could do the same exercise for a mountain bike race. What it looks like to me though is that, as long as you're not racing for long periods of time (like in road races or marathon MTB races), you don't need to ride much longer than 2.5-3 hours. 4-6 hours puts you way over your energy expended in a MTB or 'cross race.

Of course, matching energy is only half the story. Training just to match energy will still get you smoked in a bike race. I don't want to delve into the other half of the story in this post, but I will say that I think I'm spending way too much time working on "fill rides" and not enough on the latter.