Functional Threshold Power Test

Posted by Dan on 29. April 2009 01:59

I set out today for Chesapeake's Peter Teeuwen's Time Trial course. My objective was to retest my functional threshold power. When I got my PowerTap last October, I did this same test and my FTP was 266 watts. I retested at the beginning of March after some decent early season training and it moved up to 279, which is where I've had it ever since. Several weeks ago, I started noticing my Intensity Factor (IF) exceeding 1.0, which means I was consistently able to ride harder than my threshold. That could only mean that my FTP should be rested as it probably needed to be raised (a little). The Mean Maximal Power Curve for the last 28 days indicated it could be between 290 and 300.

The downside to doing this now is the URI I've been fighting for 2+ weeks. I was completely off the bike for 7 days, then took it easy for a week while I got back in the swing of things. I'm probably exhibiting the behavior that gets athletes into trouble by pushing hard when they should be recovering and taking nice 2 hour CP180 rides. When this occurred to me, I was already unloading the bike and it was too late.

For this ride, the winds were blowing from 230 (SW) at 10 knots, gusting to 15 knots (12/17 mph). The temp was around 88 degrees. I'd say it was hot, but not like tires melting to the pavement hot. The course starts out going south for about 6 miles, then makes a 10 mile loop and returns down the initial 6 mile stretch. When I rode this TT last year on my road bike, I did it in 0:57:57. As the FTP test is the maximum average power sustainable for 60 minutes, I did two laps of the lollipop before heading back to the car to be sure I had enough data.

Another purpose for this ride was to test out a HED H3 aero wheel that East Coast Bicycles had let me demo. I've never ridden on an aero rim any deeper than the 31mm "aero" rims that come on a the Trek Equinox. My research says the tri-spoke HED wheel is great and does a fantastic job of eliminating the turbulence from spokes by eliminating the spokes altogether and replacing them with three well-designed carbon airfoils. Sounds great, but I've also heard that they're unstable and sensitive to winds. Before laying down my hard-earned money, I wanted to see for myself.

I used the first six miles as a warm up, spinning for a minute then recovering for a minute and gradually picking up the pace and intensity. The PowerTap was telling me my heart rate was 210+ when I got in the aero position (my max was 181 last time I tested it). If I sat up, it quickly came down to 160. I haven't a clue why. I tested this a couple times during the warm up. I adjusted the strap and snapped it a few times, but it wasn't going to come down. So once again, I was flying by perceived effort and not by keeping the heart rate at 100% of max.

I haven't ridden my TT bike in over 3 weeks (since the Conquer the Canal TT on 4/5) while gearing up for a crit-heavy weekend just prior to me getting a virus with a bacterial infection and deep hatred for all living things - me in particular. Before that, I had not logged many hours in the aero position, so it's hard to say whether it was my handling skills that needed work or the quartering headwind coming at me at 50 degrees acting on the wheel (optimal is 17.5), but I was fighting the bike. Not a lot, but if I relaxed and let the wheel go where it wanted, I'd probably still be working my way out of the deep ditches out on Shillelagh Rd.

The rest of the ride was pretty boring. I was breathing heavy, wondering when I would stop worrying about watts long enough to take a drink. I was sweating profusely and had whatever the Mucinex worked free streaming from my beak. I wasn't coughing, so that's something. I'd occasionally look down and see 215 watts and get on it hard. When I'd see 340+, I'd let off. I knew I hadn't improved that much and the longer I stayed there, the shorter this ride was going to be. I completed my two laps and made the right turn down Shillelagh Rd. towards the Walmart and what was sure to be my black Volkswagen Oven. As usual, the effort showed signs of cracking on this stretch. By the time I reached the Ruritan Club (start/finish for the PLT TT), I could no longer stay seated. It was either stand up and ride or get off and walk. I don't know who made the shorts I'm wearing, or more importantly, the chamois, but when I find that person, I'm going to make them eat them. You can call me El Barto.

So there's the back story. Here's the important part: the data.
The entire ride was 34.11 miles long and it took 1:26:56.40 making the avg speed 23.7 mph and avg power 245 watts. This included the warm up and that period where you pass what you know is the 1 hour mark and just stop pedaling for awhile until you realize you cannot coast to the car.

The peak 60 minute period:
Distance: 24.498 mi
Normalized Power: 263
Average Power: 260
Max Power: 650
Average HR: 182 bpm
Average Cadence: 103 rpm
Average Speed: 24.5 mph

While an average of 24.5 mph is pretty good for an hour, especially with today's winds (never a tailwind), I must say I'm disappointed in the average power output. 260 represents a significant drop from what it was and even more from what I thought it should be.

And finally, my list of excuses:
10. No bottle cage, couldn't reach water bottle in my jersey.
9. I had a water bottle in my jersey.
8. I forgot to put electrical tape over the front wheel's valve hole.
7. I had the front wheel on backwards.
6. I wore fingerless gloves.
5. I wore my non-aero helmet.
4. I was spooked by what I thought was an alligator in the road.
3. I used my legs for other stuff yesterday.
2. I got caught at the light.
1. I confused my Assos Chamois Cream with Icy Hot.

For now, I'll leave the FTP alone. Next time I'm doing the 95% of the 20 min peak power and switching to DZNUTS high viscosity chamois cream in the distinctive black tube.