2x20 and ft questions...confused, please help

cshong88

Hi, I'm a junior and have a couple of key questions concerning 2x20s and FT. I am pretty confused, so could you help clear some things up for me?

1. I did my first 2x20 yesterday on the trainer, well rested having got back from a vacation. I was not really sure what number to go for on my first interval, so I sort of arbitrarily picked a range of 205-230W (based on a 72-77% range from my MAP test of 286W; the range is 206-220W). I ended up with an AP 212W, NP 213W. My RPE on the 1-10 scale was like this: by end of 1st ten minutes a 5 (strong, heavy); by end of 15 minutes a 6-7 (7 being very hard); by end of 20 minutes a 7. I rested for 5 minutes and when I did it again, I got an AP 213W, NP 214W. This time, RPE was: 1st 5 minutes a 5, 1st 10 minutes a 7, 15 minutes a 7-8, by the end a 9 (extremely hard). I felt pretty dizzy when I finished my interval, felt a little sick, but I recovered within a couple minutes.

Based on this test, is my FT 213W? Or is that too high? I am wondering because...
I went outside today to try to do the 2x20 again. This time, the plan was to do the 1st interval at 213W with a much better pacing strategy (on the trainer, my power had a slight downward trend). I tried to find the best flat road I could and did an out and back. This time...avg. power was 192W, NP 193W. Morever, my RPE was 7-8 by end of first interval...definitely harder than it should have felt. It was actually quite frustrating because the road was not really flat...it undulated with slight but noticeable gradient of up to 4% which made the downhill sections especially annoying to maintain power. In fact, 10 minutes into the interval I was already feeling like an RPE 6-7. I decided to stop after the first interval, discouraged that my avg. power was so low and the fact that I plan on trying the 2x20 with the better pacing strategy again tomorrow on the trainer or on another flat road (hopefully I can find). The rest of my ride was just a tempo ride.

I am especially dumbfounded because despite all the variation in my power in this 20 min. interval (at least relative to my 2x20 on the trainer), my NP was only 1W greater than my AP and 20W lower than my NP on the trainer...yet RPE was much greater.

BTW...my LT hr is 183 (based on 1hr hard ride...see below for power info from this ride). The first 20 min. interval on the trainer was avg. 178. Second was avg. 186 bpm. On the interval outside, the avg. HR was 181 bpm.

Should I be doing 2x20s on the trainer? It feels so much harder outside, and my numbers show. What is my FT, too, based on these results? I am almost positive that I can at least do a over 200W avg. power 1 hr TT on the trainer...although I have been advised not to do a full out 1hr TT because it set backs training and is very hard to do (especially to duplicate competition motivation). I did do a hard 1 hr ride though (basically my attempt to do a 1 hr TT on training motivation). I think I could have gone harder but it was difficult too because the terrain was very hilly (some climbs up to one mile long with 8-10% gradient, short climbs 15-20% gradient...and of course there are big downhills as well). I had an AP 192W and NP 198W. But I know that I can do over 200W on trainer for one hour...

but what's the point of having an FT on the trainer if you can't reproduce it on hilly terrain outside?

2. I am wondering then, during an actual 40km TT in competition, how do you pace yourself using the powermeter? I'm sure there are not any 40 km TTs out there that are literally board flat...and I don't know if I could maintain 213W in a 40km TT outdoors even if there is only slight elevational changes...and are you supposed to go by AP or NP- for example, what happens if the TT is hilly...often AP can be much lower than NP.
3. I did my 2x20s indoors with a cadence of 88 (almost 88 throughout..slight variations of 2-3 rpms). This was the easiest cadence I figured out for me to maintain wattage. However, when doing the 20 min. interval outside, I found myself going to lower cadences (70-80) in big gears to maintain power...especially on downhill sections. I am wondering...when doing LT intervals outside (if you even do them outside), is it easier to maintain high power with a higher cadence than what you would use on the trainer?




Thanks very much.

-Chris

whoawhoa

Chris-you were probably just fatigued from the previous days 2x20's. I know I can't do 2 days of 2x20's at the same power (really speed on trainer) even if I feel really fresh.

For your second question, search a few pages back on this forum. There were some really detailed discussions about tt pacing.

whoawhoa

http://www.cyclingforums.com/t27139...g-strategy.html

one thread on tt pacing. Gets pretty complicated/confusing though.

RapDaddyo

What are you using to measure power on your bike and on your trainer?

cshong88

Powertap...of course for both trainer and outside then. Please help!

BTW, if I was too fatigued from the 2x20s, then that probably means 213W is too high to be FT since Coggan cites FT as power routinely produced during 2x20s?

frenchyge

There is a different sensation associated with riding indoors v. outdoors, at least initially, although power generation is not dramatically affected after one gets used to the difference. Was this your first outdoor ride in a while?

The weather was unseasonably warm here this week, allowing me to get some outdoor rides after a long period on the trainer. The outdoor rides were definitely tougher on the quads. I, too, find that it's necessary to shift into a big gear in order to generate decent power going downhill, but generating high power is much easier while climbing than while on the trainer. If only there were some 10 mile long hills around here.

I'd say 213w is about right for your FT. Keep in mind that it's not necessary to do 20min intervals right at 100% of FT. Anywhere between 90-105% of FT would be perfectly valid depending on how you feel that day.

RapDaddyo

You have asked three different questions. First, you want to know what your FT is based on two rides. Second, you want to know about TT pacing. Third, you are interested in the relationship between power and cadence.

As to your first question, I agree that fatigue probably played a role in your second day's performance, especially if you haven't been riding much recently. Most people have the opposite experience between the road and a trainer (i.e., they find it harder to ride a 20min interval indoors at their typical road power). I'm more concerned with the steady decline in your power during the course of the interval(s). You should be able to maintain a steady power for the full duration. So, your FT may be a bit lower than 213w, but I don't think it's as low as 192w (based on the data you provided).

As to your second question, TT pacing is a very complex topic because it integrates two very complex sciences -- physiology and physics. The short answer is that the easiest way to ride a TT is at constant power, but the fastest way to ride a TT (other than a flat course with no wind) is at variable power. However, the specific power levels for an optimal variable power pacing strategy is a very complex question.

As to the relationship between cadence and power, that is going to vary from rider to rider. Look at Lance Armstrong vs. Jan Ullrich. Lance clearly favors higher cadences and Jan clearly favors larger gears and lower cadences. Both are right -- for themselves. Cadence is where I think RPE is really valuable. Get up to what you think your FT is and try different gears from ~75 - 110rpm. Find the cadence at which you feel the least fatigued after 5-10 minutes. But, be careful about monitoring your HR during this experiment. I can virtually guarantee that your lowest HR will be at the lowest cadence. Very misleading indicator. Hope this helps.

Squint

I think you should be less concerned with pinpointed FTP and just start training. If you're doing 2x20s, for example, you're going to be improving and increasing power so if your FTP estimate is too high or too low, it will soon sort itself out. When training with power, you get a sense of what power outputs you can maintain for a particular workout. When you get more power at less PE or less PE at the same power, it's time to bump up your target power output.

SolarEnergy

cshong88,

Your FT power will probably improve from weeks, to weeks. And so will be you ability to pace on a TT. Both are closely related. One help the other, vice versa.

cshong88

But I am still concerned about the vast difference in my 20 min. intervals outdoors vs. indoors. Yes, I have not been riding for the past couple days (rode for the first tim eyesterday doing the 2x20s indoors) since I was on vacation, but I had been riding outside periodically since then...maybe 2-3x a week.

Should I be "blaming" my lower power output but higher PE outside on the slightly undulating terrain or my lack of adjustment to riding outside? Where do you guys do your longer intervals...outside or inside and if outside...on what kind of terrain?

frenchyge

Inside. There's no way I could maintain 300+w riding down the rolling hills here. Of course, going uphill I'm at 375w without even thinking about it, but I don't like to do intervals where I'm trying to guess my NP based on uphill v. downhill powers.

RapDaddyo

You may not realize it, but you have raised a fascinating question. More on that later. As to your question about whether the terrain affected your ability to attain a comparable NP (or AP) outdoors to your trainer ride, it depends on how you rode your variable terrain intervals. It sounds as though you were trying to maintain a constant power. As frenchy said (btw, happy new year, frenchy), it is much more difficult to ride downhill (or downwind) segments at high power (e.g., at or near your FT). When you ride uphill or upwind, the hill or the wind provide continuous resistance and it's easier to maintain high power. Downhill and downwind is much more difficult because the bike keeps "running away from you" as you apply power. So, it would have been easy to maintain your target power (213w?) uphill and it would have been very difficult to maintain your target power downhill. The result -- both NP and AP below your target. But, it should have been entirely possible for you to ride a variable power ride at your target of 213w if 213w is indeed your FT and if you weren't too fatigued from the day before (and you shouldn't have been with only 2x20s). You would have had to ride the uphill segments at a higher power than the downhill segments. You'll have to experiment a bit to find the right power levels for each segment of your route, but you should be able to find a combination that results in your target NP. And, there's no question in my mind that if your FT is truly 213w, you should be able to ride a 20min variable power interval at NP=213w. That's because a 213w 20min variable power NP is the physiological equivalent of a 213w constant power ride.

Now, for the fascinating part of your question. It's one thing to say that a 213w variable power NP ride is physiologically equivalent to a 213w constant power ride, but it's not obvious that therefore the physiological adaptation is equivalent. We do intervals to attain a specific physiological adaptation. So, the question is whether we can flip the interpretation of NP. Does a 213w variable power NP ride induce an equivalent physiological adaptation as a 213w constant power ride? I am not a physiologist or sports scientist, so I don't know what the answer is technically, but I feel as though the answer to the question is, "Not exactly, but close." I don't even know if it has been tested, but I'm sure Andy C or Ric could provide a logical (vs. empirical) answer based on the mechanics of adaptations. Good question.

rmur17

Answer: it's depend on how variable P(t) was during the 213W NP workout

If you consider some typical cases (~ hour-long workouts):

(1) A quite low VI ride say 213W was produced on an undulating TT course -> then it's pretty obvious that since NP ~=AP that the resultant adaptations will be the same. This is a TT effort made variable by the demands of the course (and the desire to pace it variably of course ).

(2) A relatively high VI ride with say 6x5WI/5RI Level 5 intervals. NP could be at FT (213W or very close to it) yet AP would be much lower. As the effort isn't quasi-steady state like the TT, and L5 Vo2max is being targeted, I don't believe the adaptations will be close at all.

(3) An even higher VI ride with L6 intervals (say 10x1WI/3-5RI). I haven't tried an hour's worth of these but I believe it would be possible to approach FT (213W NP) for the hour. The adaptations versus that of the steady-state effort are clearly different despite very similar NP's.

All IMHO. The ex.Phys blokes can correct me I'm sure ...

rmur

frenchyge

I'd be pretty confident that the answer is 'no' if NP was significantly different from AP for the ride in question. *Any* hard ride of ~1hr will have an NP close to FT, regardless of the ride composition. In other words, NP is useful for telling us where we are likely to hit the Power vs. Duration curve for a particular ride, but doesn't tell us anything about how we got there (to the limit of the P/D curve). It's a more insightful way of 'averaging' the power over a ride.