20-Minute FTP Test from FTL Live Jan 12th, 2021 workout

ryan · January 13, 2021, 1:33am

Hey everyone,
Coach @trevor and I hosted the follow-up FTP test today on Zwift after completing the Ramp/MAP test about 5 weeks back. We were discussing the approaches, different outcomes, how to pace and perform the workout, and other points. We though it would be useful to share our performances from today, so here they are. Please feel free to upload your results to get some clarification, help with interpretation, etc!

So my test went off pretty well. We went through a good warm-up and completed a 5 min blowout segment before starting the 20 min test. This is meant to turn through those anaerobic stores so the 20 min test better reflects your sustainable threshold power. So 5 minute effort first:

Here you can see the 5 min effort. And if you’ve been listening to Trevor in the past where he talks about pacing for these, one hallmark of an appropriate 5 min blowout would show a consistent upward trend in HR. This means we’re not “settling in” or pacing the effort. If you watched the recorded session, you would hear both us us breathing very heavily during and throughout this effort. Although I did pace somewhat in order to keep some ability to talk during the workout, you should feel like you don’t want to talk much at all during this one.

As for the 20 min, here’s my screenshot from that one:

For the 20 min effort, you can see the very stable HR response in red. Power remained very steady throughout, and if you participated in the workout with us or watched it afterward, you’ll hear @trevor talk about chunking and breaking this up into 5 min segments. For reference, here’s how it played out with my TT.
310 watts / 158 beats
304 watts / 165 beats
302 watts / 166 beats
306 watts / 170 beats
So the first 5 minutes HR will be a bit off because of the lag in the response time, but you can see the consistency through the middle 10 minute portion. Finally, by the end there was some creeping up toward max.

Looking back on my MAP/Ramp test from 5 weeks ago, that was a stellar day. Max HR was 181 beats, and based on my peak 1 min power, my threshold was around 300-310 watts, which for this time of the year is very high for me (too high, really). Comparing to today’s effort, which was really more of a “typical” day, HR was definitely not near max, I wasn’t at the same level of readiness this time around, and these numbers reflect a much more realistic threshold value. So based on the results today, I’m looking not at 300-310 watts, but more like 288-295 watts, and HR threshold 160-162 beats, which is very typically what I would see most often for threshold efforts.

This brought up the point of ensuring you use your “typical” responses to set and update your ranges rather than those banner days where the moons are aligned and you see massive breakthrough performances. Those are usually not the most realistic, and if you chase the training ranges and numbers from your peak performance, you run the risk of over-cooking yourself and failing at the intervals.

Share any of your thoughts or files, data, etc. from your testing and we can get some good discussion going to help you dial in ranges or analyze your sessions!

Coach Ryan

trevor · January 13, 2021, 2:21am

That’s a great analysis by Ryan. A lot of good advice that I hope helps all of you reading this.

Here’s my data. Very similar story with a few differences. I’m actually going to share some graphs from WKO+, but so that you can compare my effort to Ryan’s, here’s the graph of my ride in Training Peaks:

The 5 Minute Effort
I really like the heatmap visual of my power in WKO5, so here’s my five minute effort visualized in WKO:

This was actually not a good effort. Notice that my heart rate never even hit threshold and my power rose through the effort. When I do a good test, I want to see a much higher heart rate and at best, I’ll maintain my wattage. Usually it declines. Here’s a much better example from a test I did in November:

Two things contributed to my five minute test not being a good test today:

I turned erg mode off in Zwift, but I’m pretty sure it was still active. I noticed that, despite shifting many times to find the right intensity, my power stayed right around where the test protocol wanted me - which included a harder final two minutes.
I just recently came back to altitude. When I’m not acclimated, I have a very hard time riding above threshold. So, I admit, when I saw that I wasn’t going as hard as I normally would in a 5 minute effort, I didn’t really have it in me to complain too much.

The 20 Minute Effort
Here’s the heatmap:

I was much happier with this effort. Notice that heart rate was fairly flat sitting very close to my threshold (dotted red line.) Also notice that my power was very steady and consistent throughout.

As Ryan mentioned, I like to “chunk” a 20-minute test. I broke it down as follows (my average power for each chunk is in brackets):

0-5 minutes - (334 watts) - find my rhythm - i.e. get a sense of how I feel that day. I don’t try to seek a particular number. Instead, I use that five minutes to figure out where I’m at for that day and then settle into that intensity (which is as much based on feel as power.)

5-10 minutes - (334 watts) - I’ve found my rhythm and now I hold it. In many ways this chunk is the easiest.

10-15 minutes - (332 watts) - conversely, this chunk can be the hardest because now it’s starting to hurt, but the finish line isn’t in view. My goal is to push through the pain and sustain my power as much as I can.

15-20 minutes - (339 watts) - now I give it everything I’ve got.

A few things to notice:

My heart rate came up quickly, bit I didn’t actually hit my threshold heart rate until about five minutes in.
Once I hit threshold heart rate (172ish) I held it there for a while. In fact, when I saw 173 or 174, I’d make myself back off slightly until it returned to 171 or 172. But, then in the last five minutes I was more willing to let myself creep over.
Finally, if you look at my graph from Training Peaks (above) you’ll see that my power was less consistent in the final five minutes. I was starting to push and stand up a few times. I was having a harder time staying as steady as I was in the first 15 minutes. But I didn’t mind because I was in the “give it everything” chunk.

Finding Threshold Heart Rate
We talked about this on the ride, but I thought a visual might help. To figure out my threshold heart rate, I’d take the average heart rate for the middle section of the time trial. I’d start right after the oxygen deficit portion appears to be over and then go until it looks like I was pushing a little above my threshold to get to the finish line. I’ve highlighted that portion in grey:

The nice thing about finding threshold heart rate is that it’s far less time dependent. Your 20 minute and one hour power will not be the same, but threshold heart rate taken from a test like this should be about the same as what you’d do a one hour TT at. For example, here’s a 40K I did a few years ago:

Notice that I still took me the first five minutes to get to threshold, but then I sat there the rest of the race. Not as steady an effort by power, but it was a very hilly course.

Schils · January 24, 2021, 3:16am

I’m interested in this thread and it has seemed to have stalled. So, I’m throwing some of my testing data into the ring for analysis.

I want to give Coach Ryan a big thank you for fielding some of my questions as I was preparing this post.

Background information:
This was done on a dumb trainer with a crank spider power meter. Now that I have a means of measuring the power, I am able to confirm that my interaction with the trainer is a bit frustrating. As the fluid warms up the power required goes up exponentially. Also the test was several months ago so my memory of specific events is a bit foggy.

BTW, I have another test scheduled for the end of January and am looking for suggestions for “better” testing,

Here’s the entire work-out. I have broken this up into the warm up section and the test protocol section below.

Test Protocol: 32 minute test based on reading about Joe Friel’s test protocol and Kolie Moore’s test protocol from Empirical Cycling Podcast and Training Peaks articles (I think that is where I read it).

Minute:
0 to 7: pretty basic step from 145 to 225 watts.
9-11: 2 minutes at estimated (anticipated) FTP
11-13: 2 minutes at 110% of estimated FTP

Self analysis: Based on Coach Trevor’s analysis of his test, I think I need more time at a higher power. While my HR was increasing the entire time for both intervals, it didn’t go above my post test determined LTHR. It certainly felt “hard.”

Test protocol specific information:

Estimated FTP prior to test: 265 watts. This was based on my Power curve over the last 4 months of having an actual power meter and Critical power estimation from Golden Cheetah.
20-30 minutes: ramp from 90% to 100% (240-265 watts) of FTP to get into for the effort mentally.
30-40 minutes: steady effort at FTP
40-52 minutes: ramp from 100% to 105% FTP (265 to 280 watts)

Self analysis of results:

LTHR is average heart rate from minute 30 to 52.
Average power is over entire test, minute 20 to 52.
Power drop at 35.xx minutes. I don’t remember! I’ll say it was a pause to readjust myself, stand up, and collect myself mentally.
Heart rate spike at 49.xx minutes. My story is… the increase in power as too much (taking me into VO2 max or above). Based on the HR data I was bumping up to my max HR. I was definitely starting to feel the lactate and fatigue. My quick assessment was to drop the power down, collect myself, drop the HR, and return to the protocol value or even back off to estimated FTP. As can be seen power was bouncing around a bit from 49 minutes to the end as well as a few drops in power throughout the test.
Maybe I need to mentally set myself to suffer more. Although, based on my training after this test; a FTP of 250 to 265 seems in the ball park. A week or two before, I did a 60 minute test and recorded an average power of 240. I’m willing to share that if anyone is interested, it has some sections to improve as well.

Okay everyone, I’ve got my big boy pants on so fire away. Other than maybe suffering more, where are areas of improvement.

bgkeen · January 24, 2021, 5:24pm

I do not have too much to add. It looks like you have a protocol down that you feel is measuring what you want. I have recently done a test and was going to put it up for review for a different reason…

Since you already did your 1 hour test and FTP is suppose to measure what you can sustain for 45-60 minutes. It looks like from what you have shown for numbers for this test on your hour test, it seems reasonable that you the 250-265 range for 45-60 seems reasonable.

Was this the first time you have done this protocol? I would think the thing that helps already doing the base line, it give you are target as you do them again to try to keep things a little more stable as you perform more of them.

But I will step aside for now and let the pros weigh in

Nice work!

ryan · January 27, 2021, 10:58pm

@Schils, great post and analysis!

My thoughts are going to fall in line with your 5th point in the self-analysis. I think your 60 minute test from the 2 weeks previous would suggest that 240w area as a reasonable starting point. I say this because looking at the power file, we know there are some limitations, particularly with the trainer setup. I remember riding on the old Cycleops fluid trainers where you could feel the resistance changing 30-45 minutes into a workout as the fluid warmed up. It was very hard to find consistency.

Since you have the 60 min test at 240w, I think you smartly started off a bit higher assuming you would do more power for that shorter test. Although, to your point of the feeling being “hard” overall, I think we can push for a bit more. These should feel maximal (for that duration), and I have to wonder if the slower HR response taking nearly 10 minutes to achieve the plateau could have been hastened a bit with a slightly more aggressive starting power. This would definitely change the overall feel of the ride to something more than “hard.” Thinking ahead to future testing, I would almost see this as a good way to test your progress within this particular protocol, but as your fitness changes it might be hard to estimate the appropriate ramp rate to always achieve the highest average power for that duration.

As far as FTP goes from this test, I think your range of 250-265 is close, maybe 265 is a bit on the higher end from what I’m seeing so far, but if you set a range of 240-255 to start, it would at least encompass the lower end of the range. And if you really felt that at the 280w segment in the protocol was pushing you over the edge, we know that’s definitely too high. Looks like that was going from 265 - 280w gradually, but I would make an educated guess that if we had you riding at 265w for 30 minutes straight and measuring lactate, that might not be a sustainable, or steady state, level. The way the HR trends up from minute 44 on, would suggest that we’re starting to get over threshold by that point (and I would wonder if that would have been sustainable for 32 minutes if you were able to set the power to that level for the entire duration). For short workouts, that upper end might be ok as a boundary, but for sustainability, I like the 240-255w range.

Thanks for posting, and @bgkeen let’s see your data if you’re still thinking of putting it up on the board!

Coach Ryan

Schils · January 28, 2021, 4:33am

Coach Ryan,

Thank you for the feedback. Funny you should mention a Cycleops trainer, I use a Fluid 2 for my everyday training and had (key on past tense) the same observation. I ended up changing the fluid and it is a little more consistent, now it only takes 1 minute for the resistance to change by a large amount. Since I have a power meter I can adjust for the longer term drift with cadence, I end up spending 90% of my time in 2-3 gears. For my scheduled test in a couple of days, I plan on switching the bike to the Kurt Kinetic Road Machine that the wife’s bike is currently on. Still a dumb trainer; but, I find it much more even in dealing with longer intervals.

Now that I have done quite a few threshold level intervals on the trainer (not more that 2x/week), I think I have a better understanding of how to ramp up my heart rate without blowing up.

Your suggestion of 240-255 as a starting range is exactly what I came up with on my own, when I was creating my test prescription earlier this week. My plan is to ramp from 240-255 over 10 minute, 255 for 30 and ramp from 255 to 275 over 10 (this is my stretch goal) for a 40 minute test. My realistic goal is to hold 255ish for the 40 minutes. 3 weeks ago I did 2x20 threshold and averaged 255 and 253 with a max HR of 156 and 163 for each and I didn’t feel wasted after. BTW, my max heart rate is 179 from this summer and confirmed again in early December.

I have one other question regarding heart rate. Based on the last test and the threshold intervals I’m thinking 153 bpm is a starting point, any thoughts on going slightly higher like 158 (88% of MHR)? I remember in one of the fast talk podcasts Dr. Seiler mentioning 88-92% max heart rate as the range to performing polarized intervals, this is due to the metabolic tole on the body. Is this advice something to consider as a point to start backing off slightly and keeping a higher average. Or since this is a “test” go higher, just at a slower ramp and be wasted as the clock count down to zero. I would like to avoid the longish breaks that started around 49 minutes in the example above.

All of this effort is for my own knowledge and as a starting point for my next training plan. My plan is to do a 9-week polarized block where FTP is really just a line-in-the-sand for the first couple of high intensity work-outs. Then I plan to use the results from the previous work-outs to tweak the future work-outs.

I think I need start mentally preparing myself for the “suffer!” Tongue pressed in cheek, sort of; but, then kind of true. I am planning on providing a de-brief while things are still fresh in my memory. That is unless I am totally not in it mentally and blow up after 10 minutes.

BTW, I did a 4 minute all out a couple of days ago and almost had lunch come back for a visit. To say the least, I paced that interval very poorly.

bgkeen · January 28, 2021, 1:25pm

@ryan I am working on my write up now

bgkeen · January 28, 2021, 1:36pm

@Schils

When I do hard workouts and “tests” I make sure I got through my off-the-bike mental and physical “warm-ups”. I start with breathing and almost meditative work, like visualizing the upcoming workout, before I get into my dynamic warmups. This ends up being a guide to not only determine if I am ready physically but also mentally. If I cannot get through that, I know I should not attempt the hard workout/test that day. Most of my workouts where I quit are more because I have mental stresses and a state of not able to focus that is brought on by life stresses - bad sleep, late start and trying to wedge into day, home distractions, not enough recovery, etc.

Best of luck with your future testing!

bgkeen · January 28, 2021, 3:56pm

Here is a link to my write up doc in case you care to look. I will work on formatting it for here:
bkeen 20 FTP Test

Update: My attempt to make this forum friendly:

20 Minute FTP Test Analysis

Protocol

I tried to mimic a similar test that Trevor and Ryan did. In the past I would usually test 5 minute max and 20 minute max separately. I do like knowing those numbers independent of the 20 minute max formula to FTP because I like to set some of my harder intervals base on those numbers and not FTP.

I have thought in the past the 20 minute test overestimates my FTP. When I look at that number and realize how I feel at the end of 20 minutes, I do not think it is realistic to maintain the FTP number for 2+ times over the duration. This test I am looking to be part one of an upcoming (in the next 3-4 weeks at the end of my current block to work up to a 60 minute threshold effort) 45-60 (hoping for 60) to see where the numbers fall. I think I fall into the category where I can suffer at high powers beyond my threshold (anaerobic) for a good 5-10 minutes, so the theory of flushing that out seems like a good idea for me.

Prep and set up

After doing the Festive 500 I took about 3 weeks to do 5x5s workout about every 3-4 days (depending on feel). I had different variations of the intervals to holding 80-95% of prior 5 min max, “Batmans”(starting hard, cruising, finishing hard), and varied (a batman, mixed in with a steady, mixed in with 30/30s, etc).
I also worked in my strength and easy running days for the day after a 5x5 session. After my last 5x5 I took it easy, endurance rides working in neuro work on and off bike before test day.

Prior Numbers

Note: Last test performed in last calendar year. PRs are best numbers in the last 3 years. “Formula FTP” is 95% of 20 Minute Max (some software have estimate my FTP in the 310-315 range, which I do not think is reasonable). “Reasonable” FTP is a number I think it reasonable somewhere between 90% of 20 Minute Max and what I see as my highest 60 minute power (from rides, since I have never tested).

Jan 22, 2021 Test

Warmup with some higher intensity surges.
** Recover for 5 minutes
** 5 Minute Max
Recover 7-10 minutes
20 Min Max
Recover and a 1 minute and 30 second effort thrown in…
If you must know
** TV – Angliru Stage from 2020 Vuelta
** Headphones – Cinch cycling podcast’s Workout mix #4

5 Minute Max

20210122_tp_4dp_5min

In the past when I did a 5 minute max I would start hard, find a point where I will be steady the entire time and then try to end hard. This day, I wanted to see where some of my limits were. I started off hard and then looked to hold on. If I felt like I could not hold, I would dial it back until I push hard again.
After my initial push, I brought my power down to where my prior best was to see how it felt. I was feeling good and held it there. I started to feel like I could push harder, so I put on a few more watts. The rest of the interval I went between pushing hard and then dialing back until I felt the burn leave my legs.
Overall –
** My power was higher than I ever had in a minute test. I knew I was going to best my prior PR. Which did scare me with the 20 minute test coming up.
** My heart rate didn’t hit max. This is surprising because usually the 5 minute max will get it there. During my 5x5s leading up they would get me close in the 190 range. I may have had a bit more in the tank. I was feeling great and having a great day. In review this was my PR by about 30%. There is a part of me doubting the numbers…

20 Minute Max

Since I am in unchartered waters, 20 minute test after a 5 minute test, I decided to deviate from my normal finding a power (usually predetermined) and holding steady there. This time since I really wanted to know what my limits were after a 5 minute max, I did the same I did for the 5 minute – start by pushing hard, settle into a comfortable area, push a bit harder until I needed to bring it down, bring it down to when the burning stops, when ready push hard again. I did mentally break up the segment into 5 minutes parts to where I would make a decision on how to attack the next – those decisions stayed the same. Within the final 2 minutes, I felt like I could go a bit stronger, so I did…
I think my HR looks to be what to expect for a good test. Is it climbing too much above LTHR? In the past I have thought I worked too hard and my HR would end up closer to HR Max.
Once again I was surprised that I bested my PR in this workout. I was not expecting to come close to my prior after the 5 minute effort. This was a good 10watt increase.

Thoughts

Given this information, I am a little shocked how I felt pushing the watts I was. I feel like a lot has to do with my prep leading up – training plan, diet, rest, recovery. Although I would expect a big drop in the 20 minute max, I do not think my prior tests I did as rested as I was.
I still think my numbers are overestimated, especially if I am in the middle of a training block using FTP to set intensity, where I am not as rested as I was for the test.
I think given these numbers and knowing my ability, 300 +/- may be a reasonable workout FTP for setting zones. I think I was on a good day with good rest. Most training days will not be as recovered, rested, and having everything going my way. But…how does it fare to what I can do on a real 45-60 minute test? I should know that soon.

Questions

Does this jump seem too high? Should I be looking into if my equipment was good? I did notice my tire may have been a little low. But would that make the power lower?
Could other things have helped this much? In the past year I have:
**Started doing strength in a different manner and focus.
**Focused more on recovery and rest
** worked on breathing and relaxing on the bike. I do notice breathing more consistent and not as panicked.
Does my HR look like I was going the correct effort to for a 20 min test to determine FTP? Was I too far above LTHR?

ryan · January 29, 2021, 10:51pm

Great test @bgkeen! That was a great review of your process to prepare, and your experience throughout. So to your questions:

There is always the consideration of equipment malfunction and it’s smart that you’re asking yourself that question, just in case something went awry. Are you on a ‘wheel on’ trainer? The tire slip can certainly be a factor if you don’t have the same pressure on the wheel. I remember the indoor cycling days with Computrainers and we could get some vastly different numbers for power if our turn-down pressure on the drum was different, or if we were running a different tire inflation pressure.
It could also be that you just had an absolutely stellar performance. It sounds like you’ve done a number of things to improve recovery and performance, and paired with your pre-test routine, that may have been adequate to give you this big performance. New power PRs and the slight reduction in HR could indicate that you’ve made some good adaptations, especially if the perception of the effort was manageable or lower than expected for the effort you were putting out. On days like that I would never set the FTP result as my true FTP. I would expect, like you said, that other things such as fatigue, stress, etc. will reduce my ability to perform to this same level in all upcoming workouts.
Your HR response looks to be pretty consistent. Definitely increasing over the second half of the 20 min effort, but also predictable. It seems to me that as you were working on pushing until it became too uncomfortable, that served to push the HR up, and then as you backed down, there was an opportunity for it to drop back to LTHR. However, because you were building fatigue throughout, some of those surges may have been too much to recover from and we’re seeing that progressive increase from essentially what could be looked at as a version of over/under or on/off intervals within the test. Overall though, your average HR being 177 is only 1 beat above your LTHR line, so I wouldn’t consider that as going too far above.

So maybe somewhere between your reasonable FTP number and ~300 would be a pretty solid threshold range to give yourself. Knowing that on days where you’re just 100%, you can push more in that upper range, maybe slightly above. But likely that on typical days you might be pushing 285-295 watts. Of course you’ll have HR to guide you as well.

Thanks for sharing!
Coach Ryan

ryan · January 29, 2021, 11:05pm

@Schils, I think that 153 is a good starting point. Based on your 2x20 workout I would actually recommend holding off on bumping up to 158 for now. The 2x20 I’m guessing is meant to be done consistently right around your threshold, correct?

Seeing that bump from 153 max to 163 max HR in the second interval (would be interesting to see the drift that occurred there and how the interval progressed since it’s a long one) would suggest to me that for the endurance, durability piece of it, you might consider running the 2x20s as HR based with a slightly lower power target of 240-250w rather than the upper end of ~255w. That will allow you to still accomplish the goal of the training session, but focus on building more time there without experiencing that HR:power decoupling.

The 88-92% MHR recommendation is solid, and that provides a great training stimulus, but if you’re a touch below that around 85-86% it’s going to still provide an appropriate stimulus and might even allow you to feel recovered quicker, which would allow more work at that level to be accomplished. When I get into the 2x20 routine I tend to start a bit on the conservative side and aim to maintain a consistent HR. Since that session is still “only” 40 minutes at that intensity and many events require more of that, I find that going by HR and allowing power to rise naturally seems to be a good approach - then when I’m like 2 hours into an event and already tapped out those ~30-40 minutes of threshold effort, there’s more in the tank to keep the power up over the long term.

Coach Ryan

scooter · January 26, 2022, 11:51am

though this may be a hijack of this thread, I was unable to find any discussion of the topic of test repeatability anywhere. What bothers me is that most of the tests are specific for some physiological aspect and not a general reality, ie ramp vs 2x 8 minute, vs 20 minute vs 4DP etc… As well there are so many factors that go into the test outcome, rest, fueling, caffeine or not, mental state, etc. When people get hung up on test results they have often not taken into account all of the factors and to the best of my knowledge there has been no proof of repeatability of results or even the variance of results. If you do test x and get result y what is the +/- on that result? What is then a meaningful difference… and finally how much of the change is the result of just getting better at taking the test?

I like the idea behind XERT in that though they say no testing they still mean you have to push your limits to failure. The thing is the failure can be in a variety of different situations which may still give different results for their fitness measure(s). Trainer Road is saying they are doing something similar inferring fitness from typical results beyond a test. Of the “tests” I sort of like the 4DP because it makes you go through a lot of different situations not just one. I think the area of testing still has a way to go. All that I infer from any test is did it change and was that change meaningful or just inside the region of noise? I would really love to hear more thoughtful commentary on testing. (I am not referring to physiological testing of lactic acid level, oxygen exchange levels etc where we have very specific measures vs some secondary measure like power or heart rate these are a whole different beast from what I understand.)

scooter · February 16, 2022, 3:33pm

bumping this note… I am curious what physiological systems are actually being interrogated by the different test protocols and as noted how the actual protocol can influence the results and how to interpret them. I like that Ryan and Trevor are clear that the results are ranges and not defined numbers. So I think what I am asking is as follows:
what is the reality of riding for 1 hour as hard as you can… what does that tell you vs
the various test protocols all supposed to infer some form of threshold power:
the ramp test what does it really test?
the 2x 8 minute test same what is it testing
the 5 minute then followed by 20 minute test (as shown in variations above)
the so called 4dp test with sprints, 5 minute, then 20 minute then back to a 1 minute hard effort.

These all inflict differing amounts of pain and stress on the athlete but what are they really testing and how much of the outcome of these and all of the other variations of these tests really tell us as athletes what we are achieving? Further are there any take aways as to how they differ?

Final question, how much of the result is the basis of familiarity with the protocol, ie getting better at the test not getting more fit?
thanks

AJS914 · February 16, 2022, 4:56pm

This article may help:

I switched to the baseline test last year and I’ve found it much better than the 20 minute test. It’s a lot easier to pace. I usually end up doing a 35-40 minute test and it feels like a much truer reflection of my MLSS. With the longer effort you get a good feeling of a sustainable effort and when you go above threshold you feel it.