Thursday, November 5, 2009

Ironman Data and Comparison

While no two races are identical, valuable information can still be gained from observing performance differences between races. I did two IMs this summer, one in Lake Placid and the other in Louisville. At IMLP I went 9:41 with a 1:05 swim, 5:10 bike, and 3:19 run. At IMLou, I went 9:19 with a 1:12 swim, 5:07 bike, and 2:54 run. The major difference between my races was running 25 minutes faster at Louisville. What allowed me to cut that much time?

At Lake Placid, I was exhausted at the start of the run. Anyone that has run a marathon knows they're hard enough to do when you start fresh. Starting a 26 mile run feeling depleted is not a recipe for success. Why was I so tired? My best guess immediately after the race was that riding too hard was the primary cause of my fatigue. My gut feeling was that I pushed a bit too hard during certain segments of the LP bike course, especially when heading uphill and into the wind near the end of the course. Though I had nutrition/dehydration issues during the race, I believed those developed during the run. By inspecting my LP race data and comparing it with data I collected at Louisville, it appears that nutrition issues (and potentially the weather) were the primary cause of my lackluster LP run.

My powermeter allows me to accurately compare the two races. At IMLP I averaged 204 W on the bike, and I averaged a nearly identical 201 W at IMLou. Still, average watts don't reveal much. Consider an extreme example: one can average 200 W for an hour of riding by (1) riding at 200 W for the entire hour or (2) riding at 600 W for twenty minutes and 0 W for the remaining 40 minutes. Riding at 200 W for an hour is not very difficult. Riding at 600 W for 20 minutes is spectacular, if not impossible.

My initial hypothesis was that my race data would reveal that I spent more time at high wattages (e.g., > 270 W) at IMLP than at IMLou. To offset the greater time spent at high wattages during IMLP, I also expected to see more time at lower wattages during IMLP than during IMLou. Looking at the actual data, however, shows that this is not the case:
IM Lake Placid Power Distribution


IM Louisville Power Distribution


It turns out I spent almost the same amount of time at above 270 W during both races. Incidentally, I intended to cap my effort at 260-270 W during both races, so ~45 minutes spent above 270 W seems to indicate bad pacing. However, I now think that my IMLou run proves my bike pacing was pretty good at both IMLou and IMLP. Also, the 45 minutes above 270 W were not much above 270 W, with only a tiny portion of that time being above 300 W.

The main pacing difference between my races is in the 210-240 and 240-270 W ranges, where I spent about 20 minutes more at LP than at Lou. I do not think these pacing difference were responsible for my poor LP run, however. Why? First, 210-240 W is right around the range I expect to ride on the flats, so spending more time there shouldn't effect me much. Second, I only spent a paltry seven more minutes in the 240-270 W range at LP than at Lou, and I think that difference would not have as drastic effect as 25 minutes on the run.

After reviewing my data, I think my run difference was mainly the result of becoming dehydrated starting on the bike at LP. I think my nutrition suffered before the run at LP even started, and that a lack of calories/water was why I was fatigued at the start of the run. The weather, I believe, was a factor in my nutrition. At LP the weather was sunny and warm, and I was sweating a lot on the bike and craved fluids. Dressing in all black probably didn't help. Lou ended up being a perfect day weather-wise, though I still wore a full sleeve white top a la Torbjorn Sinballe. I think I perform better in cool weather, and will use that top in most future IMs. Other factors may have played a small roll. For example, LP is a more difficult run course than Lou, though I'd expect a pretty small difference (~5 minutes?) due to course difficulty.

Reviewing this data is useful for me becomes it allows me to confirm that my bike pacing strategy works. I don't need to change my pacing for next year (though hopefully I can bump up all the wattages by a bit by increasing my bike fitness).

I'll analyze my Louisville run in one of my next posts. While I am happy with the time, my pacing was not ideal.

3 comments:

  1. Evan, while I haven't seen the bike profile for IMLou, I can't imagine its anywhere near as hard as LP. The fact that you were within a couple minutes is a testament to your biking. Thats awesome! 2:54? Damn.

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  2. The Louisville bike course was surprisingly difficult. With just about the same wattage as I put out at Lake Placid I was only 3 minutes faster. I was a bit discouraged during the race because I expected to be more like 15 minutes faster. That's one nice thing about a power meter - it tells me that my output was fine at Louisville.

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  3. What a great write-up Evan. This is the sort of stuff that allows us to pinpoint next year's goals with that much more accuracy. Of course, this winter's training will also have an effect. We'll have to see what you can sustain while training at altitude. For Ironman cycling there's a definite drop-off (in what you can maintain at altitude) but it isn't so great at it might be if you were to train more often at FTP-like intensities, where you can expect about a 8-10% decrease in output.

    In the simplest sense (and this is just a rudimentary example) if we find that you're only really capable of sustaining 190 watts for 5hrs at altitude at Ironman-like intensities (cost) then we'll need to collect more time at goal outputs comparable to what the demands of race day will bring. A hot race like Kona equates to being at altitude, but a race like Lake Placid is nothing like it. Hanging around 200 watts all the time because altitude demands it, well, wouldn't help you reach higher goals.

    A good test this winter: 3hrs at IM-like intensities (as determined by HR), recording power and PE. Avoid dropping off too much as winter hits in earnest and you'll be that much more ready to crank up the "real" training when spring hits.

    Anyway, I'm rambling. The key right now is to see the effect that altitude has on you to know how to go about some of your quality indoor rides that should commence in due time.

    Ryan...heat is the unmeasurable variable in your first sentence. A course profile is easy enough to quantify but conditions rarely are. Lake Placid's course ain't so placid, while Louisville's heat and humidity probably level the playing field when comparing the two courses. Knowing your sustainable output is the best way to overcome any obstacle but only if this output falls within the realm of having a realistic cost to that effort. Same as it ever was!

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