Training & Nutrition - Heart rate or power for FTP on trainer

I have started using a KK pro trainer and last week I did a FTP test (2x20). I had an average power of 200 watts according to the power curves for the Kurt, and an average heart rate of 175. I am 47 years old btw. 2 days later, I get back on the trainer and target 85% of my 200 watts of power, which should put me in the 170 watt range. However, I was struggling to keep 135 watts and my heart rate for the (1x20) was 177. So I guess I had not fully recovered from the initial FTP test 2 days earlier. But, should I target 85% of my FTP heart rate, or 85% of the Kurt power curves. I know that a lot of outside factors can influence my heart rate, but because of that, isn't that a more accurate determiner of exertion or stress? I could do my training at 85% of my heart rate, but not 85% of my power. What are your thoughts?

But, should I target 85% of my FTP heart rate, or 85% of the Kurt power curves. I know that a lot of outside factors can influence my heart rate, but because of that, isn't that a more accurate determiner of exertion or stress? I could do my training at 85% of my heart rate, but not 85% of my power. What are your thoughts?How much riding have you done prior to your FTP test?

I have been on the trainer 3 times a week for 1 hr. each time Since January. This is however after a 6 month layoff.

HDK

I would use heart rate as your guide unless you have a power tap/SRM. using the power curve charts is innacurate at best

I would use heart rate as your guide unless you have a power tap/SRM. using the power curve charts is innacurate at bestThe KK power charts are supposed to be within about 3% of actual power so you should it shouldn't have a problem using those.

I assume you are using a big fan as overheating (and increased heart rate) are a common problem for indoor riding.

If you're only getting 3hrs a week to ride try backing off on the intensity a little. Or better yet try riding every day and mix up the workouts. Some shorter intervals and more time at 75% of FTP. As you get stronger you can add in more intensity.

Personally, I don't think 2x20 FTP tests are advisable until you've got some reasonable miles in your legs.

I am using a fan, but I guess I thought I could pick up where I left off. Maybe too hard to soon. I'll try backing of and do some longer rides on the trainer at lower intensities.

HDK

skin temp makes a lot of diff. I have the same trainer (love it) and outside I average about 30-40 watts more at a given perceived effort, even with a fan inside.

Wow, that's encouraging. I couldn't believe I was that weak after the test. I looked up the cadence and gear ration's I was using on Sheldon Brown, and it appears that my Garmin was displaying the wrong speed by a few MPH. So in the end, I was trying to ride 25 watts above my FTP. No wonder it felt so hard.

The KK power charts are supposed to be within about 3% of actual power so you should it shouldn't have a problem using those.

I assume you are using a big fan as overheating (and increased heart rate) are a common problem for indoor riding.

If you're only getting 3hrs a week to ride try backing off on the intensity a little. Or better yet try riding every day and mix up the workouts. Some shorter intervals and more time at 75% of FTP. As you get stronger you can add in more intensity.

Personally, I don't think 2x20 FTP tests are advisable until you've got some reasonable miles in your legs.


The power as calculated by the KK equation is usually within 5 watts or so of my actual power, so I'd agree w/ the 3%. The first 10 minutes or so it's a little off, but after that it's pretty solid. This is using 2 1/2 turns tightening after the tire initially touches.


It's WAY more accurate than using HR. My HR for a similar power interval can vary by close to 10 bpm depending on my fatigue level, and the second 20 minute interval is usually 5-10 beats higher than the first for the same RPE.