Newbie Trainer Training HR Questions

Hi,

I've been hitting the trainer a lot in preparation for my first Ironman, and even though I got good use out of the machine preparing for two HIMs last year, I've started to wonder about a few things now that I spend so much time on it.

This year, I upgraded to a new bike, and got a Garmin forerunner, so I can tell speed and cadence.

According to the plan I'm following, I should be spending a lot of time in z2. For me, that's at least 130 bpm. But 3 times out of 4, I find it hard to get to that number. I'm spending most of my time between 115 and 125. I really need to push it, to feel like I'm in z4, to get past 130.

There have been times where I can juice myself -- start with a pedal-gnashing sprint, get up above 130 and sustain it for more than an hour.

More often though, I've been on the big ring, smallest gear, with a cadence of 85; I'm sweating, but I can't seem to get out of z1. If I hit a higher gear, my cadence drops precipitously... I don't want to be turning the pedals that slowly, nor can I keep it up for very long.

On the other hand, I've been trying to work with higher cadence as well, especially in the downhill portion of race course simulations. At 100+ rpms, it's supposed to be relaxing -- but I find it exhausting. The trainer I saw said I was really quad-dominant... maybe that could have something to do with it.

Do you guys have any thoughts on how variable (and generally underperforming) my workouts have been? Could the variation just be a result of mounting the bike on the trainer differently?

On the other hand, one of the HIMs I did last year was Savageman, a very hilly race -- and my heart rate stayed pretty low too. Could I have a different heart rate standard for the bike?

For what it's worth, heart rate training for running has worked out well for me. It took some work, but I feel pretty good hitting my z2 138 bpm targets, and it's taught me to be a lot faster.

And then, on the road -- how do you sustain a plan like "an hour in z2 with 5 min at z4, six times, with a 3-spin"? I'm barely in z1 when I'm on the road, but I'm going a lot faster than I do on the trainer, but then I hit a climb, and I'm in z2-z4.

I feel like I'm missing something. Maybe I need to learn more bike technique. Maybe I should start saving up for a powertap. Can anyone help?

Thanks!