IM CDA 062611 Biking Details

The IM CDA profile course was quite different than what I had been riding, and after previewing the course I had to adjust my plan and expectations accordingly.  I tend to try to keep my power as consistent as possible, which means riding uphill easy and pushing on the downhill portions.  Looking at the grades on the hills and talking to friends who had ridden them in practice, it was apparent that keeping my power under 220 wasn’t going to be possible.  Also, with the curves associated with the downhill portions, I wasn’t going to be able to push on the ride down.  This meant I’d be doing more push and recovery, as opposed to maintaining constant power levels.

One of the Garmin options on the Edge 500 (and a new option in the 310XT as part of a recent upgrade) is the ability to not count the zeros as part of your power average calculation.  Realizing I’d be coasting down a lot of the hills, I chose to disable zero calculations, to give me a better view of what my legs were seeing so I didn’t have the tendency to see a low power value and feel compelled to try to increase my average power.

Going in to the race, I had intended on trying to get my average power (without zeros) at around 165 watts.  I’ve found that when I transfer my ride to TrainingPeaks, it adds the zeros back and I typically see a drop in power of around 3 to 5 watts on the overall average.  Looking at the hills and the likely stress on my legs, I thought low 160’s would probably be a good target.

For comparison, I’ve included my race data as well as my 6/5 training ride (relatively flat course) and my 5/15 CompuTrainer ride on the CDA course:

6/5 Trail 5/15 CT CDA 6/26 IM CDA
Miles 112.1 111.89 111.5
Elev. Chg. 2087 5226
HR Ave/Max 119/136 125/132 128/157
Pwr Ave/Max 161/452 165/224 151/443
Cad. Ave 82 83 84
Spd. Ave 19 17.9 17.9
Time 5:54:55 6:15:06 6:12:47
Z1 Min 45 11 121
Z2 Min 232 325 140
Z3 Min 68 39 69
Z4 Min 10 0 31
Z5 Min 2 0 12
Z6 Min 1 0 4
Norm. Pwr. 166 172
TSS 281 252 318
IF 0.69 0.59 0.72
Note that with my zeros turned off I was reading 160 watt average at the end of the ride at CDA, so I lost 9 watts with zeros factored in.  This basically shows that I spent a lot more time coasting on this course than I did riding the Ankeny to Woodward trail (I never coast when riding the CompuTrainer).
In looking at the data, I feel I stayed in a good target range overall.  Although my average watts were only 151 (with zeros), my normalized power and intensity factors were higher than my last training ride, meaning I put a little more stress on my body in the race than I did in training… but not by a lot.  This can also be seen in my HR averages, which show higher numbers in the race than in training.  Although some of this may be impacted by coming out of the swim first, likely a good portion of the increase is due to the higher wattages that were needed to climb the hills (my peak HR was much higher).  If I would have strictly been following a zero included wattage (151) and ignored HR, I would have ended up pushing harder than I did… and likely burned up my legs prior to the run.

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