RPE (+HR?) vs Power for TTs - Page 4

Just for you, Stormer, I went over my PM files for the past few days, looking for durations of ~5min with steady power at or near my estimated 40K MP. Here are the average power and EOD (end of duration) HR numbers for the segments. I estimate my max HR is 160bpm. You decide if HR is a good basis for pacing.

298w 147bpm
286w 146bpm
270w 131bpm
265w 131bpm
263w 136bpm
258w 132bpm
245w 125bpm
236w 132bpm
200w 124bpm
188w 130bpm

What do you think?

What do I think? 160MHR? Were bikes made out of wood when you graduated from high school?

<---makin' fun of the "old guy"... j/k

Seriuosly though. I don't know what to make of the numbers, I'm not familiar with how they all relate. And franky, as you mentioned, they sure don't look very useful. I just don't get how the same amount of work, all things considered, could have an effect on HR as great as that shows. I'm not getting it. I can't come up with any reason why a HR of 130 can get you either 188 or 270 watts. That seriously defies a lot of work/effort type things I tend to believe in. Work (watts) is effort, all other things being equal, your HR is the price you pay for those watts. Again, this assumes all things being equal (no difference in bike, or temperature, drag) Just you being you, exactly the same as possible per test. I can see maybe 10% differences in HR or watts, whichever you choose, but what could possibly account for a 43% increase in power for a given price paid. Or a 30% reduction in power, depending on which number you choose to use.

I'm curious about the EOD. End of duration number. How does that compare to average HR?

All I know is I get some consistency without the meter. Just as someone else mentioned about a coach he had. I attached a file with 2x8 min TT's. No power meter, nearly identical in result. Both averaged 157HR over the duration, I skipped about the first minute on both to account for HR lag, and then both showed 160HR average for both efforts.

Could it be said that the watts, very likely, were nearly identical in both runs?

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__________________
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"Was" 39 year old guy Blood pressure: 143/84, Resting Pulse: 68, weight: 230
"summer 2004" 40 year old guy. Blood pressure: 121/66, Resting pulse: 45, weight: 175
1-1-2005 Blood pressure: 115/55, Resting pulse: 44, weight: 170
6-1-2005 Blood pressure: 105/52, resting pulse: 40, weight: 175
40k-TT, 1:05

Almost definitely not. I'd estimate that the power was significantly lower on the second run. Here's why:

I don't wear an HR strap anymore so I can't post a pic, but back when I did, and would do efforts like 2x20 or whatever, HR increases from the start of the first interval all the way to the end of the last interval (unless the effort was too easy, then it tends to flatten out). Having the same ave HR over both intervals implies to me that the power was lower on the second interval.

I looked around a bit and I found this in my records:

Polar #4:
Duration: 15:20
Min Max Avg
Power: 170 427 289 watts
Heart Rate: 123 173 164 bpm

Polar #6:
Duration: 15:10
Distance: 6.019 mi
Min Max Avg
Power: 147 460 284 watts
Heart Rate: 125 174 166 bpm

Note that while power went down a little bit, ave heart rate crept up. (Admittedly though, this is back when I used a polar so the power levels are suspect, however these are both single laps around the same course so the power should be relatively precise if not accurate.)

I used EOD because I just randomly looked for ride segments of ~5min at or near my estimated 40K MP. The HR at the beginning of the segments could have been anything, but HR should have stabilized after 5 mins. To give you the average could be misleading based on the HR starting points (could have been anywhere from 100 to 130).

Heart rate is closely correlated with power under carefully-controlled conditions (e.g., in a laboratory-type test), but less so "out in the field". Take a look at Figure 1 in the chapter I wrote for USA Cycling for an example.

More generally, I think you're looking at the question far too narrowly. Again, I highly recommend that people read John Verheul's comments in that article on the Competitive Cyclist website (esp. his point #1). He's a really smart guy, and have spent more than enough time coaching people via heart rate and now power to understand the key differences.

Stormer also has a pretty nice HRM suite compared to mine (ie, recording instantaneous speed, altitude/gradient, cadence, etc.) and has some good notes about environmental conditions (e.g. wind speed differed on this interval), so he's already gone a long way to try to eliminate or account for some of the variability.

In my case, I would only get an HR trace and would try to enter a lap every 2-5 miles (if I remembered... ) to try to capture an avg pace over that distance. Switching to a PM was a no-brainer for me, and I'm getting a lot more data - universally applicable data captured more easily - than ever before.

You mean this one?

http://www.competitivecyclist.com/pdf/power_v1.pdf

(Had to search a little for it myself but it's safely downloaded now)

rmur

Actually, the price you pay for intensity (watts) is acidosis and other physiological responses, for which blood lactate is the best available proxy (I'll be a lot more articulate after I have listened to Andy's 8-hour lecture). Your HR is another proxy for intensity of effort, but not a very good one. Now, as you may know, I have been fooling around with variable power pacing strategies for TTs, even highly variable power pacing strategies. I have a nice little test loop very near my house where I ride when I want to stay close to home (e.g., thunderstorms in the area or I'm temporarily out of tubes -- this was the case today). My glutes have now improved enough that I am willing to risk seated efforts >200w, but not much more than ~5 min. Today I did one of what will eventually be hundreds of VP pacing tests on this little loop.

Let me describe the loop. It is basically a 2.7 mile rectangle, with 90 degree turns where I have to slow down but not stop. The 1st leg of the rectangle is .5mi and basically flat. The 2nd leg is flat for ~.3mi, a slight downgrade for ~.2mi, then a climb for ~.3mi to flat for ~.15mi. The 3rd leg is flat for ~.3mi, then a nice little climb for ~.15mi, then flat for ~.1mi. The 4th leg is a constant, very slight upgrade. The grade changes are what makes the loop interesting for a TT pacing test lab.

I don't know how well you can read the attached file (too bad I can't attach a .wko file), but my intention was to ride at a normalized power of 300w, but with <15sec accelerations out of the turns up to 1000w and pushing the climbs at up to ~450w and backing off on the downgrade to ~175w. The major thing I was testing today was the 4th leg with the slight upgrade. My VP pacing strategy says this is a poor choice for reducing power because the speed loss is too great. I was basically seeing if I could "cheat the tax man" by pushing up the hill at the end of the 3rd leg. The bottom line was that I paid a price on the 4th leg and had to back off to ~250w for about .7 mile. I have to work out the gain/loss to see if I would have been better off to do the climb at ~300w and then carry my full sustainable power into the 4th leg.

Looking at the results, I was pleased that I hit my primary objective right on the button -- 300w NP. The AP (average power) was only 292w, to be expected since I had pushes >15sec above my sustainable power number. But, the constraining variable is NP, not AP. My accelerations were 450w, 563w, 938w and 652w out of the four corners and I think I should have pushed them all up to ~900w since they were <15sec and were "free bites." My back-off on the 2nd leg downgrade paid off because I maintained bike speed ~29mph and increasing power would have had a neglible effect on speed. My push to ~450w in the upgrade on the 2nd leg should have been more of a stair-step in power -- I should have gone to 450w in ~2sec and then held it instead of the steady ramp-up. My push at the end of the 3rd leg was probably poor pacing strategy because it is followed by a slight upgrade and the loss probably exceeded the gain.

The graph lines are watts (yellow), cadence (green), speed (blue) and HR (appropriately red). Before commenting on HR, let me caution you that this is a ride in which intensity was managed by power. I have no idea what the results would be if I attempted to do the same ride with intensity managed by HR. The first observation about HR is that it took 2.5 minutes to catch up to power. It is highly likely that if I was managing intensity with HR that I would have gone at a higher intensity in those first 2.5 minutes and put myself in a hole at the outset. Second, if you look at the 450w push up the climb on the 2nd leg, HR responds, but only after the push was done. HR would have been of no value in managing that push (or the very important recovery following). This is what I meant in another post when I said that the interval was over before my HR got its socks on. Finally, the 3rd and 4th legs had some very important power management stages but HR just bumped along at ~150, oblivious to all the real action (watts). Bottom line question: What was the value of my HRM for pacing strategy on this test ride? Answer: zero!

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Yes, that's the one - I thought I'd cited it in this thread already and didn't want to repeat myself, but I guess it was in another one.

Cool! 7 minutes even. Ok, now go ride at a steady 300W pace and see if you're faster or slower (yes, right now... ).

Actually, I'm not sure I'm seeing the downhill part of leg 2 where you backed off to 175W. Don't be cheatin' on your recoveries, now - Senior Nationals may depend on it.

How did you know that you needed to pull back on leg 4? Were you watching Avg Watts for the interval during your ride and saw that you were going over 300? It shouldn't have been fatigue induced on this 2.7 mile loop at 300W, right?

Nice post. Thanks.

Well, first things first. My glutes appreciate my caution. But, yes, I will do that on another day. And, I plan to ride it with my watts display taped over. That'll be fascinating. Maybe, just maybe, I'll be able to steady out at ~300w after the first 3 minutes, but I'm scared to death of going out too hard (I mean way too hard as in 400+w the first 3 minutes). And, I already know that my HRM will be completely useless in managing power on the pushes and following recoveries. Those'll have to be totally RPE. And, I can't wait for a howling wind (we get that here regularly) to test my VP pacing strategies in the wind. That'll be cool.

It's the part just before I ramped up to ~450. It wasn't very long in time, because I had to carry power for the first, flat part of the 2nd leg and, at nearly 30mph, it doesn't take very long to cover a lot of ground. That's part of the recovery dynamic. On a downgrade, even though you back off the accelerator you don't get much recovery (in time) because you're going so fast (assuming, and this is crucial, you get bike speed before you ease off the throttle). The perfect TT course would have upgrades followed by downgrades with about a 3:1 ratio of upgrade grade to downgrade grade.

It was funny, but I just felt that if I cranked it right up to 300w after the brief acceleration coming out of the corner that I wouldn't be able to hold it. And, of course, I knew that I had dipped into the well and was going to have to pay the price. Again, this wasn't a max effort test. I needed to "feel" that I could ride at this pace for 1 hr. You'll notice that I didn't sprint to the finish, because I wasn't viewing it as a finish. I just held it steady. I believe one can put oneself in a hole in a very short time, even 7 minutes. Go into the red zone and you must plan on a recovery.

C'mon... completely useless? What if you had no computers on the bike at all? Are you saying it's possible you would be unable to ride?

I feel I could ride with no computers at all. That said, It wouldn't be any fun. I enjoy watching the little displays. Also, ride, not race. I'm not sure I could train without the computers on the bike, that's a bit more finite and targeted (hence all the debate). I bet I could have a good z2 recovery day with no computers at all, and stay in the zone. I'll have a day like that again on the 16th. I'll try it.

__________________
-------
"Was" 39 year old guy Blood pressure: 143/84, Resting Pulse: 68, weight: 230
"summer 2004" 40 year old guy. Blood pressure: 121/66, Resting pulse: 45, weight: 175
1-1-2005 Blood pressure: 115/55, Resting pulse: 44, weight: 170
6-1-2005 Blood pressure: 105/52, resting pulse: 40, weight: 175
40k-TT, 1:05

You have to read the entire statement.

What I'm saying is that maybe I'll be able to ride (with HRM only) at around 300w after the first 3 minutes (assuming I don't go too hard in the first 3 mins), but that my HRM would be of no value to me in managing my uphill pushes and the following recoveries (crucial to a VP pacing strategy) because the pushes are over well before the HR ramps up. These pushes are often <2 mins and the HRM is just too slow to respond. Likewise, the recoveries are often only a couple of minutes and the HRM would just be starting to come down when the recovery is done and you ramp up to sustainable power again. What I truly believe is that I won't be able to manage my intensity very well even at a steady state but that it'll be an over/under pattern and, by definition, will cost me time. I know you want the HRM to be this instrument of precision, but it ain't.

P.S., Stay tuned for the topography of your course. I may be able to help you in an hour or so.

I raced for 5 years with no computer of any kind, so, yes, I know.

Did you guys really race with slide rules taped to your handlebars way back then?