Wednesday, June 4, 2008

The Downside of Power-Based Training

I recently had an interesting discussion with one of the athletes I coach. He's a pro who trains for Ironman-distance events. I've been coaching him since December and as I do with everyone I work with I've emphasized data analysis, especially his power and heart rate files following key workouts and races. Using WKO+ I examine how each of the key, weekly workouts went looking for ways we can improve performance by tweaking how he trains. And, of course, I do the same thing with his race files. I require that everyone I coach trains AND races with a power meter as this is the best way to discover the stresses that the athlete must be able to cope with and thereby model workouts to better suit those demands. Every week he gets several WKO+ charts for the past several days from me that discuss what I am seeing along these lines so he is on the same page with me. It's a great feedback tool.

He understands that the data gleaned from these files is critical to his continued improvement. He also understands that when he does a key workout I'll discuss the results with him later on. So there is no "hiding;" not that he would. He's quite professional in his training. But he senses a bit more accountability given that I will eventually see exactly how he carried out a planned session and so he strives to produce perfect power files for me.

This is where the downside comes in.

He realized a couple of days ago that when he is racing he still feels this need to produce a perfect power file for me. This means, to him, in part, keeping the average and normalized powers high. So in races he is less likely to coast a downhill, something I advise IM athletes to do, because that would lower his "numbers." It dawned on him that being more focused on power data than race results was counterproductive. That was a crucial awakening which will help him to race faster.

In key workouts one of our purposes is to stress the body with high power loads and high heart rates. Speed is not critical. Stress is. A race is just the opposite. The whole purpose here is speed. And if he can produce high speed with low power and low heart rate all the better. The idea is to keep stress as low as possible while riding as fast as possible. Doing so means he will have more in the tank for the run.

His realization of this basic concept is a breakthrough for him. He'll be a better athlete because of it.

Don't take this to mean that you shouldn't pay attention to your power meter and heart rate monitor during races. You should. In fact, doing a long, steady-state race such as an Ironman with a power meter is almost like cheating. Once you know your numbers, the ones that will produce the optimal bike ride, it's just a matter of paying close attention to them regardless of outside variables such as wind. On the other hand, monitoring speed on a bicycle is pretty much a waste of time. It is certainly a good way to waste a lot of energy as you try to maintain velocity into a headwind--and then fade badly later. With a power meter you just ride your number. You go slower but you are still producing your optimal time and you don't fade and limp home. A watt is a watt. A mile-per-hour is not.

Don't let your desire for perfect data files get in the way of having your perfect race.


At June 10, 2008 8:36 AM , Anonymous Anonymous said...

Very timely for my training. In my preparations for IMCdA I have had goal power numbers on my workouts. When I get home the first thing I do is download and obsess about how I rode. Often times I find myself pushing it where I won't during the race as I want to have higher numbers.

I'm looking forward to using the PM as a governor and coasting on the down hills and maybe even using a tailwind as an excuse to save some for the run. I know my avg's will be lower, but I think my run split will be grateful.

At July 25, 2008 10:38 AM , Anonymous Anonymous said...

Thanks for that post - it's a great thing to realize that in the end, on race day, it's not the guy with the highest power numbers that wins - it's the one that goes the fastest.

That being said, how do you determine "your number" for an ironman bike leg?

At July 25, 2008 10:59 AM , Blogger Joe Friel said...

anon--It's largely determined by trial and error in long rides using the decoupling measurement procedure I've written about before here and posted on my website (see Determining Aerobic Threshold at It's typically between 60 and 80% of FTP depending on fast you are. The athletes I coach who just want to finish are around 60%. The pros I coach are in the upper 70% range.


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