Your FTHR is the highest average sustainable heart rate you can produce on either a 40km time trial on the bike or a 10km run. So, whatever your average HR for the 20 minute TT portion of the test, minus 5%, gives you a "functional threshold" for HR... an important number to know for training.
This is the test (source Hunter Allen & Andrew Coggan):
20 minute warm up riding at a moderate pace about 65% of your max HR
3 X 1min fast pedaling efforts at 100rpm with 1 min easy recovery between each
5 minutes @ 65% of max HR
5 minutes all out. Punch it and hold it!
10 minutes easy @ 65% of max HR
20 minute time trial on flat course. Do not start out too fast!
15 minutes at 65% of max HR
15 minute cool down
So the goal is to produce the highest average watts for the 20 minutes. You can't go out too hard and then blow-up, because then you can't calculate the data. The directions say it's "better to start out in the first 2 minutes a little under what you believe to be your FTP, build up along the way, and then ride at your maximum level in the last 3 minutes." The later is what I was focusing on; building and ensuring I was working at my maximum level in the last 3 minutes.
Time-wise, I executed the test correctly. Coach says it's been surprising how many screw it up! But that was about the only positive. LOL He says, that if I did the test again today, it would come out better now that's I've done it once. It was surprising to me how the most subtle changes in stroke and balance can change the data.
The 5 minute punch was good, but when I got the the 20 mins, I started in the same place as the 5 minute punch and when my legs started to burn after 5 minutes in, I was afraid I would blow up after 5 minutes and not be able to make the 20. For about 2 minutes I slowed down only to realize I was then going too easy. What I didn't think about is that little correction cost me 10% of my testing time! Plus, every time you shift your position on the bike it's recorded and it costs you in power, so you have to get balanced and comfy on your saddle to begin with.
Keep in mind, I'm a maybe a step above a recreational rider. I've never been fit for power on my bike and only know the most basic fundamentals about stroking on a bike. We won't even get into what the charts shows about the weaknesses in my stroke! I did walk away feeling like maybe I should sell my bike and give it all up, but naaah. At least now I have a baseline. I can't be any worse than I tested, ever again. LOL
5 minute - punch and hold:
19.35265 Average Speed
177.5714 Average Watts
91.2449 Average Cadence
140 Average HR
161 Max HR
20 minute - TT
17.61005 Average Speed
146.9744 Average Watts
89.80513 Average Cadence
143 Average HR
157 Max HR
FTP Heart Rate = 149
Essentially I skewed my 20 minute time trial data by taking 2 minutes to figure out where I should have been. MC says I'd be over 18 for average speed and over 150 for average watts. He is certain, knowing what I know now, I would test better the second time.
Also, my 65% of my max heart rate really doesn't feel like I'm doing anything... so on the "easy" parts I was riding at more like 80-85%
For now though, we're using 150 as my functional HR threshold on the bike, until I retake the the test.
And yeah... I'd really like a CompuTrainer. :)