Functional Threshold Power (FTP) Estimation Test

The max power output you can hold for an hour is often referred to as your threshold power. This is the number used to determine all your power based training levels because it's kind of a magic number. If you stay below your threshold you remain aerobic and you can sustain the output for a long time. Go above it and you go anaerobic and your time is limited. The greater your threshold power to weight ratio, the longer you can go faster. The ratio is important because if your a big person you'll have to put out big power.

Many people believe a devastating sprint or short burst of speed allows people to win bike races, but if your not fast enough to hang with the group for the race, you'll never get to use your crushing short term speed. I believe this has been some of my problem in the last races. During my training this year I haven't see much improvement in my threshold power. I intend to change that and make it a priority.

As you can image, holding your max power for an hour is hard, so people have come up with a number of ways to estimate the value. This morning I used Joe Friel's FTP confirmation method. It wasn't too taxing and I'm hoping the results are accurate. Basically it's eight 4 minute repeats with one minute rest between them. Each interval is done at 10 watts higher than the previous one. Start about 70-80 watts below your believed threshold. When you see your LTHR during the interval, your done and the average for that four minute block is your FTP.

From the data it looks like I got a little carried away with the last interval because I knew it was my last one. I hit my LTHR (163) - this is my average HR during almost all races - and averaged 304W. This is my new reference point for the training going forward.


Over the next couple of weeks I'll be working on that. I would like to raise it up as high as possible before CX season where pushing a higher wattage at a lower heart rate will pay some dividends. This is the time to make adjustments, this is after all just pre-season!