Should intervals always be done at max?

[Pendejo]

I have a number of different interval workouts, including 30-second, one-minute, one-mile, and two-mile. I've always done them as hard as I can. But now I'm wondering - does anyone in the know advocate doing some interval workouts at less than max? (I don't use a heart monitor.)

 

[RapDaddyo]

I have a number of different interval workouts, including 30-second, one-minute, one-mile, and two-mile. I've always done them as hard as I can. But now I'm wondering - does anyone in the know advocate doing some interval workouts at less than max? (I don't use a heart monitor.)

By "less than max" I assume you mean less than one's max power for the given duration. If that's what you mean, I almost never do my high-intensity efforts at my max power for the duration. In fact, about the only times I ride at my max power for a duration are: (1) performance tests, (2) TTs and (3) L7 efforts. If you take L4s (per Andy Coggan's schema), I regularly ride these at the 91-95%FTP whereas my max power (depends on the specific duration) is typically 100-105%FTP.

 

[daveryanwyoming]

...I almost never do my high-intensity efforts at my max power for the duration. ..... If you take L4s (per Andy Coggan's schema), I regularly ride these at the 91-95%FTP whereas my max power (depends on the specific duration) is typically 100-105%FTP.

I'll second that! By definition doing intervals at the max for that energy system limits those intervals to the minimum time. IOW if you're targeting VO2 max work with 3 to 5 minute intervals, doing them at max effort will limit you towards the 3 minute end of the range. It also tends to limit how many total repeats you can do.

Remember training is a balance between working hard enough for the desired adaptation and doing it for as much total time as you can. Take those L4 intervals RDO was talking about; if you have the willpower, the water and the fuel you can maintain efforts at 90% of FTP for several hours. Even without postal_bag's mental fortitude it's not hard to do 4x20's or 3x30's at 90%. At 100% of FTP it's hard to get more than an hour unless you're very fresh and very motivated.

 

[wiredued]

I third the motion agonize but be smart about it back off a little and still see gains in those areas with no more effort than is necessary.

 

[Pendejo]

I appreciate the replies so far. Just to clarify my question, by "max" I mean the fastest I am able do the interval (and still survive to do the remaining ones). Every time I do a particular interval workout, I'm trying to better my previous best average times (or distances) for that type of interval workout.

Since I'm busting my ass to the maximum in a TT (5 and 10K), I've figured that the best training is to bust my ass to the maximum in my intervals. Once you have a good base and are very fit, it's hard (for me) to understand how doing intervals at less than the best you can do for that interval is going to improve your best efforts at TTs.

Just as an example, let's say my best in a 10K TT is to average 25 mph. Now let's say in training I'm going to do 6 1-mile intervals. Will doing the intervals at an average of 24 mph have a beneficial training effect? Shouldn't I try to be averaging 25 1/2 or 26 mph in the intervals?

 

[wiredued]

Just as an example on the Kurt Kinetic Road Machine trainer my 20 minute max is 248 watts (high L4) at 19.5mph this gives me an FTP of 236 watts. My 3x26 workout is 91% of FTP 215 watts (low L4) at 18.4mph this gives me more minutes at L4 and raises FTP better than an all out 20 minute effort. I'm not as familiar with L5 VO2Max targets the lowest I've heard is 113% 5x5 the max is 120%.

I appreciate the replies so far. Just to clarify my question, by "max" I mean the fastest I am able do the interval (and still survive to do the remaining ones). Every time I do a particular interval workout, I'm trying to better my previous best average times (or distances) for that type of interval workout.

Since I'm busting my ass to the maximum in a TT (5 and 10K), I've figured that the best training is to bust my ass to the maximum in my intervals. Once you have a good base and are very fit, it's hard (for me) to understand how doing intervals at less than the best you can do for that interval is going to improve your best efforts at TTs.

Just as an example, let's say my best in a 10K TT is to average 25 mph. Now let's say in training I'm going to do 6 1-mile intervals. Will doing the intervals at an average of 24 mph have a beneficial training effect? Shouldn't I try to be averaging 25 1/2 or 26 mph in the intervals?

 

[bikeguy]

Some kind of periodization is in order if you have trained for any length of time then gains do not so easily come. If you're a newbie you can pretty much see continuous gains for quite some time. My interval workouts consist of one workout where I hold back, where I figure I could continue another 30 sec to a minute for each interval, and then one workout where one, and only one interval is done so that I experience complete hyperventilation and failure, and the other intervals I still hold back a bit.

-bikeguy

 

[daveryanwyoming]

....Just as an example, let's say my best in a 10K TT is to average 25 mph.

Now let's say in training I'm going to do 6 1-mile intervals. Will doing the intervals at an average of 24 mph have a beneficial training effect? Shouldn't I try to be averaging 25 1/2 or 26 mph in the intervals?

I'm having trouble following you here. If your target event is the 10K TT which takes approximately 15 minutes at your best pace then your event is a solid L4 (per Coggan's schema) event. It's much too long to be considered a pure VO2max (L5) effort.

Your intervals are a mile apiece, so they take a bit over 2 minutes each at the speeds you listed. That interval workout seems neither here, nor there. It's not hard enough to be VO2 max work(or anaerobic endurance which is a closer match for the 2 minute duration) which would typically be 115% to 120% of your 1 hour power. Assuming a flat road and nominal drag/rolling resistance you'd need to do those two minute intervals at 28 Mph or more to make them VO2max (L5) repeats. But again, that doesn't really target your event but definitely has a place in a well rounded program for road racing.

For your target 10km TT you'd want to raise L4. You can do that with SST work at 88% TO 94% of your best one hour power or you can do multiple 10 to 20 minute repeats at up to 105% of your best one hour power. That gets back to what folks are posting on this thread. You could target 105% of your one hour power for all your workouts but most folks couldn't do very many 15 minute repeats at this level. So they back off the intensity a bit and do more total work.

I've certainly seen dramatic gains in my one hour sustainable power by doing a lot of SST work near 90% of my one hour power. So based on this sample of one (and a lot of similar posts on this forum) you can definitely improve your 10K TT pace by doing work below that level. And personally I feel that doing a lot of work is better than doing a little work at high intensity, but then I'm not targeting a 15 minute event.

Good luck,
Dave

 

[Pendejo]

Your intervals are a mile apiece, so they take a bit over 2 minutes each at the speeds you listed. That interval workout seems neither here, nor there. It's not hard enough to be VO2 max work(or anaerobic endurance which is a closer match for the 2 minute duration) which would typically be 115% to 120% of your 1 hour power. Assuming a flat road and nominal drag/rolling resistance you'd need to do those two minute intervals at 28 Mph or more to make them VO2max (L5) repeats. But again, that doesn't really target your event but definitely has a place in a well rounded program for road racing.

For your target 10km TT you'd want to raise L4. You can do that with SST work at 88% TO 94% of your best one hour power or you can do multiple 10 to 20 minute repeats at up to 105% of your best one hour power. That gets back to what folks are posting on this thread. You could target 105% of your one hour power for all your workouts but most folks couldn't do very many 15 minute repeats at this level. So they back off the intensity a bit and do more total work.

Hi Dave,
What is SST work? Also, my understanding (perhaps faulty) of the role of intervals is that you take your target race distance (for me, 10K), then break it down into smaller equal distances which are your intervals, and these you do at a faster pace than you would be able to hold for the whole race distance. For example, a track-and-field miler often trains by doing hard 1/4 mile intervals. So I've broken the 10K down into (6) 1-mile intervals, or sometimes (3) 2-mile intervals (on the stationary bike in the gym I also do intervals of one-minute duration), and do them as hard as I'm able.

The workouts you mention above are about as long or longer in duration than my actual 10K TT time, and so to my way of thinking wouldn't qualify as intervals (though they are no doubt beneficial, and I do similar workouts).

So please tell me this. I can average about 25 mph for a 10K TT where the wind is not much of a factor and there is no 180-degree turnaround. Based on the heart monitor on the stationary bike, I'd have to estimate that my heartrate during the TT is in the mid- to high-160s (I'm 60 years old). What sort of interval work would you recommend, instead of or in addition to my usual method of doing the intervals as hard as I can.

Thanks for any advice. I'm certainly open-minded, because I must admit that in the past two years I haven't progressed as much as I expected, given the training I've done. I now seem to be bumping up against the diminishing returns ceiling!

 

[RapDaddyo]

my understanding (perhaps faulty) of the role of intervals is that you take your target race distance (for me, 10K), then break it down into smaller equal distances which are your intervals, and these you do at a faster pace than you would be able to hold for the whole race distance.

High-intensity efforts (intervals) serve at least two main purposes. One, as you alluded to, is to become comfortable and relaxed at efforts approximating the demands of a race. The second, arguably more important, is to attain a targeted physiological adaptation. The "Big 4" adaptations we are usually targeting are (1) lactate threshold (aka FTP), (2) VO2MAX, (3) anaerobic capacity and (4) neuromuscular power. Each of these requires both a minimum power and minimum duration. The only one that is (typically) done at max power for the duration is #4, neuromuscular power. The other three are commonly done at somewhere around 90% of one's max power for a given duration.

 

[Pureshot78]

Every time I do a particular interval workout, I'm trying to better my previous best average times (or distances) for that type of interval workout.

I think you'll have better results by trying to increase the amount of time you spend at a particular intensity level than attempting to have a personal best each time you workout. Every couple of weeks you can 'retest' and then you'll see the benefit from your hard work.

As you progress through a training block you increase the intensity and duration of the intervals.

I retest my FTP then begin a block of training.

An example of this progression might be:
3 x 20 @ 80% FTP
2 x 20 @ 91% FTP
2 x 30 @ 80% FTP
3 x 20 @ 91% FTP
1 x 45 @ 80% FTP
2 x 30 @ 91% FTP
1 x 60 @ 80% FTP

Retest and repeat...

It is really encouraging when you see what used to be your 91% value now becomes your 80% value and you can hold it for a significantly longer time.

 

[daveryanwyoming]

What is SST work?

SST stands for Sweet Spot Training. It's a level of training that gives you a lot of bang for your training time buck in terms of raising your sustainable one hour power also known as Functional Threshold Power (FTP). Basically it's hard enough to encourage positive adaptations in terms of your ability to put out power for extended periods but easy enough that you can do quite a bit of it in one session and be fresh enough to do several sessions per week. The sweet spot occurs at around 88% to 90% of your sustainable one hour output(FTP). Lacking a power meter you can estimate this level as the speed you can sustain with deep regular breathing but still being able to drink from your water bottle. It isn't easy, but you shouldn't be dying either. Based on your 10K TT speeds I'd estimate your Sweet Spot around 24 mph given similar roads and similar wind conditions, maybe a bit slower if you're not in aero TT position for all your training.

A good way to feel your way into the SST zone is to try some 20 minute repeats with a five or ten minute easy warmup and five easy minutes between the repeats. This is ideal on a trainer or other repeatable situation. Using your speeds listed I'd warmup at 16 to 17 mph for ten minutes and then try a 20 minute interval at 24 mph. It should feel like work and take some concentration but you shouldn't be gasping or feel like retching. You should finish the first one and feel tired but decent. Do five minutes at 16 mph or so and then try a second 20 minute repeat at 24 mph. If you can't finish this one at the set speed then you've aimed too high. If it feels easy then try it again in a couple of days a bit faster, say 24.5 mph. When you can finish two or three but it takes a lot of concentration then you've got it. In time it will get easier and you'll bump the speeds up. As Greg Lemond said, "It doesn't get any easier, you just get faster."

Also, my understanding (perhaps faulty) of the role of intervals is that you take your target race distance (for me, 10K), then break it down into smaller equal distances which are your intervals, and these you do at a faster pace ...

I'm with RDO on this one, from a training standpoint intervals should be used to target adaptations and increased power for whichever energy system you're targeting. Your 10K TT will benefit from longer intervals than the one or two minute repeats you're doing now. If you know you'll never do rides or events longer than 10K then you could really focus on targeting the 10 to 15 minute range but for general riding and overall power I'd still do at least 20 minute repeats. To really get your sustainable power up you need sustain these intervals for at least 10 minutes. I know that part isn't intuitive.

I'll give you my layman's explanation and leave it to the exercise physiologists and coaches to tear it to pieces Contrary to popular belief you're not really training to get stronger in the same way a body builder thinks of strength, not unless you're a track sprinter or kilo rider who has to do high power standing starts. Sure a body builder can extrapolate from their one rep max weight to what they could lift for 10, 15 or 20 reps. But riding a 15 minute TT at 90 rpm you're talking about the strength required to do 1350 reps. From a pure strength standpoint it aint that high. The limitation is how well you can supply energy to your muscles and clear waste products. That's what you're training and since the way energy is supplied and the waste products generated change with different riding intensities targeting your training of one system has some affect on the others but doesn't completely transfer from one to the next.

In the case of a 15 minute or hour long event you're training your ability to burn a lot of oxygen, a lot of glycogen and even burn a lot of the lactate generated to keep your muscles going. If you do a one or two minute interval at these same intensities your body hardly gets into the zone before you shut down. It takes a couple of minutes to get the targeted metabolism up and running and a few more minutes to get any benefit out of doing the work.

The general power training recommendation is to sustain your repeats targeting FTP (the system you want to target for a 10K TT) for at least 10 minutes to promote the correct adaptations. Yeah it's pretty close to your target event but you won't target the energy delivery system you need with really short intervals.

So I've broken the 10K down into (6) 1-mile intervals, or sometimes (3) 2-mile intervals(on the stationary bike in the gym I also do intervals of one-minute duration), and do them as hard as I'm able.

One minute, one mile or even two mile intervals as hard as you're able to do them probably means some heavy duty breathing and some serious leg burn. At these durations if you're doing them at your max for that time you'd either be training your anaerobic endurance(L6) or maybe VO2max(L5). These are different energy systems then what you'll use during your 10K TT.

Versatile road racers need to train these systems to initiate or respond to attacks and to climb short steep hills. If the pack surges or you want to bridge to a break away or want to drop some less fit riders you need to go above and beyond your sustainable power (FTP) to make things happen. The time trialer who can't handle these road racing surges tends to find themselves all alone and off the back sooner or later so they're important skills for the road racer. But if your event is a triathalon or pure TT then you need much less of this. More importantly if you train this and fail to train your FTP your TT times won't improve because you're not training the right energy delivery system.

The workouts you mention above are about as long or longer in duration than my actual 10K TT time, and so to my way of thinking wouldn't qualify as intervals

Tru 'nuff, call 'em repeats if intervals feels funny but if you want improvement in your 15 minute pace you'll want efforts at least 10 minutes long.

Based on the heart monitor on the stationary bike, I'd have to estimate that my heartrate during the TT is in the mid- to high-160s (I'm 60 years old). What sort of interval work would you recommend, instead of or in addition to my usual method of doing the intervals as hard as I can.

O.K., this is going to be hard to take..... Forget about your heart rate. Yep, I know sacrilege. I trained with HR for many years and really believed in it, my results were pretty mixed but I held the faith. I've been training with a power meter since last summer and record both HR and power from all my rides and workouts. The HR data is all but useless, especially indoors where my HR drifts up based on heating up and other factors. I tried pacing time trials with HR and always finished slower than I thought I should feeling way too fresh. HR can be really misleading. I'm sure some folks have great sucess training with HR and the race results to back it up but I'm no longer a believer.

If the exercise bikes in your gym read out in watts you can do power based training in the gym. Just find the correct power for SST work like I described above and dial in the wattage where you want to workout. I do it all the time when I'm on business trips. I rode two hours of SST this evening in the hotel gym and dialed in the same powers I would have ridden at home on my own bike. It really takes the guess work out of pacing intervals and the gym bikes make it easy by requiring constant power regardless of your cadence. It makes it easy to catch a movie while training without drifting out of your planned workout level.

Thanks for any advice. I'm certainly open-minded, because I must admit that in the past two years I haven't progressed as much as I expected, given the training I've done. I now seem to be bumping up against the diminishing returns ceiling!

Read through the It's Killing Me but... Starting from the beginning. It's a very impressive tale of a rider roughly your age who made dramatic improvements in a very short time with most of his work on exercise bikes in the gym. Here's a link: http://www.cyclingforums.com/t-314849-15-1.html

If you decide to give this a try, keep us posted you could be the next sucess story!

Good luck and sorry about my long winded post,
-Dave

 

[workingguy]

Don't know if you have a power meter, but without one, it would be difficult to gauge how hard you should do the intervals.

You can use analyticcycling to estimate a power to speed relation.

By using the defaults, and assuming flat road.
mph W
23 197
24 221
25 246
26 275
27 305

Dave is right, the 10K is in your L4 range and boosting FTP would help this tremendously. Your 15 minute target is 25mph (246W). Assuming you can do 15 minutes at 100-105% FTP, then your required FTP is 234-246 (about 24.5mph or 25mph).

Doing 2 or 3 minute intervals will help your L5/6, but will not improve you L4 much. You should be shooting for 20 minutes at least twice, 3 is better per workout and 3-4 x per week. It should feel hard, but not impossible, and not like a leisurely stroll. Which means you should not be able to carry on a conversation.

If it's too hard to complete 20 mins at at a particular speed, then drop it down a little. Then the following week shoot for a .5mph increase. But the problems with using speed as a proxy for power are the external environmental conditions such as wind, traffic, terrain, etc.

But keep in mind that 90% FTP power will not necessarily equal 90% of that speed since it's not a linear relationship. Use www.analyticcycling.com to calculate the power to speed relationship.

Good luck.

 

[wiredued]

Or you can get the KK trainer and use this formula http://www.kurtkinetic.com/calibration_chart.php

 

[kclw]

This may be a bit different from the answer you seek.


I believe that every interval set should be done at the best possible effort. For example if you are doing 6x4 minutes you should do this at the best effort you can hold for the interval set. This doesn't mean do the first interval at 400 watts, blow up and do the next 5 at 250 watts. Pick the best wattage or effort that you can maintain for the whole set.

Any thing that is done at less than best effort should not be an interval set. Work at 80-85% should be a sustained effort not an interval set.

 

[RapDaddyo]

This may be a bit different from the answer you seek.


I believe that every interval set should be done at the best possible effort. For example if you are doing 6x4 minutes you should do this at the best effort you can hold for the interval set. This doesn't mean do the first interval at 400 watts, blow up and do the next 5 at 250 watts. Pick the best wattage or effort that you can maintain for the whole set.

Any thing that is done at less than best effort should not be an interval set. Work at 80-85% should be a sustained effort not an interval set.

This may be your unique definition, but the reality is that one can make huge progress never doing what you call an "interval set" at one's maximum power for the set. I actually tend to prefer the term "high-intensity effort" rather than interval, so I don't really care what you call what you're talking about. But it's just not true that one has to do high-intensity efforts at his max power to attain the desired adaptation and thus increased power.

 

[GIH]

I'm curious about how to choose the intensity of hard efforts or intervals or whatever. So I'll explain how I think about this and please correct me if I am wrong. First I'll assume that for our purposes TSS is the sole determinant for how hard it is to recover from a workout, so we can use this to compare different workouts by assuming that the rider selects the difficulty of workouts using TSS.

Then it seems like doing the intervals at a slightly lower intensity will allow you to do a greater number of them because TSS is proportional to IF^2. For example, consider the following two workouts, both with a 15 minute warmup 60% FTP.
The first workout is:
15 Minutes at 60%
3X20 at 102% with 5 minute recovery at 60%
15 Minutes at 60% Cooldown
This workout has an IF of .915 and a duration of 5/3 hours, for a TSS of 139
It also has 1 hour total time spent at L4.

For workout two we have
15 at 60%
4X20 at 91% with 5 minute recovery at 60%
15 Minutes at 60% Cooldown
This workout has an IF of .83 and a duration of 25/12 hours, for a TSS of 143
It has 80 minutes total time spent at L4.

They have a very close TSS score, I could have chosen the numbers to make them exactly equal. I guess I feel that the dillema is to decide between workouts with identical TSS scores. In this case I suppose the question is which yields more adaptation, 80 minutes at .91 FTP, or 60 minutes at 1.02 FTP, correct?

The other question I have is how this relates to the length of the recovery intervals. Increasing the length of the recovery intervals has a minimal effect on TSS, but it potentially has a large effect on the intensity that one can complete the hard efforts at. Also, for an effort at .91 FTP or anything less than 1 FTP it should be theoretically possible to do a much longer interval, .91 FTP for 80 minutes for example.

If I had to make a guess, I would say one gets more benefit from doing all of the .91 FTP at once, I bet most people here would also make the same guess as me. Of course, the reason to do the intervals at .91 would be because we suspect that the benefit of doing it all at once is extremely small, and that since its mentally easier to do the intervals with 5 minutes of recovery we are better off doing that. I think the 80 minutes at .91 versus 60 minutes at 1.02 is a much harder question, though. My personal guess (not educated) is that the difference is also minimal one way or the other.

Does anyone know what about L4 workouts specifically triggers adaptations to the lactate threshold? Is it something like lactate levels within the cells over time?
Maybe someone should inject people with lactic acid or lactate or whatever, or maybe with the enzymes responsible for the metabolism of lactate and see how they adapt.

Anyways, if I'm totally full of it please tell me. I try to think about this stuff intelligently, but I don't have great knowledge of the physiology.

 

[Pendejo]

Don't know if you have a power meter, but without one, it would be difficult to gauge how hard you should do the intervals.

You can use analyticcycling to estimate a power to speed relation.

By using the defaults, and assuming flat road.
mph W
23 197
24 221
25 246
26 275
27 305

Dave is right, the 10K is in your L4 range and boosting FTP would help this tremendously. Your 15 minute target is 25mph (246W). Assuming you can do 15 minutes at 100-105% FTP, then your required FTP is 234-246 (about 24.5mph or 25mph).

Doing 2 or 3 minute intervals will help your L5/6, but will not improve you L4 much. You should be shooting for 20 minutes at least twice, 3 is better per workout and 3-4 x per week. It should feel hard, but not impossible, and not like a leisurely stroll. Which means you should not be able to carry on a conversation.

If it's too hard to complete 20 mins at at a particular speed, then drop it down a little. Then the following week shoot for a .5mph increase. But the problems with using speed as a proxy for power are the external environmental conditions such as wind, traffic, terrain, etc.

But keep in mind that 90% FTP power will not necessarily equal 90% of that speed since it's not a linear relationship. Use www.analyticcycling.com to calculate the power to speed relationship.

Good luck.

Everyone, thanks for the replies, information, and advice. OK, so the consensus is that I need to be doing two or three repeats of about 10-20 minutes, at a bit lower than my max. I will start doing this. It will be a relief not to have to strain for a personal record each time I go out. But, given that my only races are 5 and 10K TTs, are there any shorter intervals at higher power that you would recommend? Or do you feel that these aren't relevant for 5 and 10K TTs.

As an aside, I'm quite surprised at the apparent accuracy of the speed-to-watts chart supplied by workinguy above. I've never had a powermeter on my bike, but since joining a gym and doing workouts on the stationary bike I've found that 15 minutes keeping a pretty steady 230 watts is pretty close to my training max. I had no idea if the wattmeters on these bikes were anywhere near accurate (of course, I hoped my true power was much higher!). But since I average about 25 mph during TTs, and it would be expected that the race adrenalin and motivation would give me more power than my training limits, the chart's estimate of 246 watts seems to be reasonably in line with the stationary bikes' readouts.

 

[GIH]

For what its worth, I usually do 20 minute efforts higher than FTP. I'm not 100% sure what my FTP is right now since I just moved from 1 mile high to 500 feet, so my power for 20 minutes jumped dramatically. But before I moved, I think my FTP was 235, and I typically did my 3X20 intervals at 255 Watts, at least in the week before I moved down. I guess my FTP based on the Monod model, I also did a 6X10 with 1 minute recoveries at 240 Watts average during the intervals, and I barely finished it (although some of that might be due to overheating since I didn't have a fan, I do all of these workouts on a Kurt Kinetic), so 235 doesn't seem like a bad guess. So that would mean that I did by 3X20s at 1.085 FTP. At my new altitude, where I have been for 3 days, I've done two 3X20 workouts at 275 Watts. I hope that lasts.

I also feel that my FTP is week compared to my power at shorter durations, which is one of the reasons I'm specifically working on it. Does this justify doing the workouts at a higher percent of my FTP, or should I focus on doing longer duration workouts to improve my endurance more (i.e. the 4X20 at .91 type workouts)? Anyways, sorry for cluttering this thread, but I'm really interested in this.

 

[Sillyoldtwit]

For what its worth, I usually do 20 minute efforts higher than FTP. I'm not 100% sure what my FTP is right now since I just moved from 1 mile high to 500 feet, so my power for 20 minutes jumped dramatically. But before I moved, I think my FTP was 235, and I typically did my 3X20 intervals at 255 Watts, at least in the week before I moved down. I guess my FTP based on the Monod model, I also did a 6X10 with 1 minute recoveries at 240 Watts average during the intervals, and I barely finished it (although some of that might be due to overheating since I didn't have a fan, I do all of these workouts on a Kurt Kinetic), so 235 doesn't seem like a bad guess. So that would mean that I did by 3X20s at 1.085 FTP. At my new altitude, where I have been for 3 days, I've done two 3X20 workouts at 275 Watts. I hope that lasts.

I also feel that my FTP is week compared to my power at shorter durations, which is one of the reasons I'm specifically working on it. Does this justify doing the workouts at a higher percent of my FTP, or should I focus on doing longer duration workouts to improve my endurance more (i.e. the 4X20 at .91 type workouts)? Anyways, sorry for cluttering this thread, but I'm really interested in this.

I think you underestimated your FTP of 235W by a wide margin if you could do 3x20 @ 255W. What are you smoking? TYSON