One of the mistakes I made in 2007 was not training enough in my "high aerobic" or "intensive endurance" zone on the bike. During the Cadence Kona Challenge, my tested Functional Lactate Threshold (the power I can hold for one hour) was calculated at 293 watts. My high aerobic zone works out to be around 225-250 watts. This corresponds to my desired power output for half and full Ironman bike legs. At IMFL, I wasn't able to hold a high enough power output even though my HR was very low.
In 2007, I tended to go for long rides at wattages below this zone or shorter more intense efforts at average power levels above this zone. While these are key rides that I will continue to use in 2008, I've specifically added a progressive program on my Computrainer which is designed to get me very comfortable with riding 225-250 watts for the 2-5 hours necessary in my Long Course races. These are weekly sessions that will progressively build my aerobic endurance to the target range by the time I reach my racing season. Each session has a warm-up and warm-down component but the main objective of these workouts is to average the desired power output for the desired time.
Here is the first part of the training progression:
Week 1: 200 watts for 1 hour
Week 2: 200 watts for 1:15
Week 3: 200 watts for 1:30
Week 4: 215 watts for 1:15
Week 5: 215 watts for 1:30
Week 6: 215 watts for 1:45
Week 7: 220 watts for 1:30
And so on. By April, I hope to be able to do Computrainer rides where I hold 250 watts for 3+ hours. Today, I completed the second week of this cycle. Last week I did 210 watts for 1:00 at 87 rpm. Today, I did 209 watts for 1:15 at 84 rpm. I'm trying to also get comfortable spinning in the 85-90 rpm range during these workouts. Also, after these workouts, I head out for a transition run, which today was 6 miles.
Hopefully, these weekly Key Computrainer workouts will prepare me for the sustained power output I need to have at IM Austria and Canada this year. We'll see!