500m World Best Score?

[Nosmo]

Nosmo,

It sounds like you and Paul are saying is that the pm1 is method is correct, or better than the pm2 method.

That is fine I suppose.

I much prefer the pm2 to the pm1 or any of the other monitors.

Regarding the pm1 rounding - via this discussion with you and Paul, I am getting that the internal conversion of the pm1 is supposed to be accurate. I think Paul said he got from C2 that the internal formula is the same in all of the monitors.

However, from that they rounded up the result (they called it truncating). That rounding is apparently what threws the wrench in the works and made the pm1 time/pace so strange as regards the average watts, inconsistent and variable - but not so strange if you feel that is the way to do things of course. I guess you didn't say this but I am.

John,
Your discrepancy of 19:55 vs 20:23 for a 5K is not a rounding/truncating error. Rounding errors and the pace dependent systematic errors that Paul reports are unrelated to the time difference you see between reported average watts and the mathematical formula. The rounding error should only be less then one second for any given piece be it 500m or 15K. Paul has described the systematic error, and there is no way that it can account for a 28 second discrepancy over 5K. He has pointed out the results were consistent within one second.
I fully acknowledge the rounding/truncating and systematic discrepancies.

Reporting the average watts like I believe the PM1 is doing, is a reasonable thing to do. It provides information about how variable the pace is. On the PM1 there is little information about split times so the average watts can be useful. For the PM3 which can be programmed for many splits, this is not necessary. I think Concept II made a reasonable decision reporting average power on the PM1. I also think it is reasonable to change it on the PM2, given its additional functionality. Neither way is "correct". I probably would have designed each the same way C2 choose to.
If the machines were producing 28 second variations for the same effort or 28 second errors of 5K, C2 certainly would have noticed it and fixed it.

best.

[johnlvs2run]

John,
Your discrepancy of 19:55 vs 20:23 for a 5K is not a rounding/truncating error.

I think that it is. Otherwise you must feel that the internal conversion from watts to time/pace is not accurate on the pm1 monitor. However I accept that the internal conversion is accurate. This means the only reason left for the inconsistent and varying difference of the times and paces is the so called "rounding" effect.

The inconsistent variable difference is certainly not confined to one second. If it was confined to exactly one second then the time/pace result wouldn't vary by as much as 3 seconds per 500m from the watts. The pm2 monitor doesn't vary at all.

I don't buy the hypothetical formula. The results speak for themselves.

I think Concept II made a reasonable decision reporting average power on the PM1. I also think it is reasonable to change it on the PM2, given its additional functionality.

The pm2 does have the average watts. This is why I was able to calculate the average watts to time/pace mathematically, and the results came out the same as the internal conversion to time/pace every time.

If the machines were producing 28 second variations for the same effort or 28 second errors of 5K, C2 certainly would have noticed it and fixed it.

Yes well that might have been one of their motivations for improving it.

[PaulS]

The Abyss is getting deeper,
and is still black.

Let's put it this way.
The object is to have covered a set distance in as quick a time as possible, and to have the requirements for that task as replicatable as possible, making "competition" valid.

Mod A with a Speedo/ODO - as long as it was set up with propper clearance around the flywheel (3 ft) it met the spec, even though ti was truly a revolution counter. (yes, altitude differences and barometric pressure could have effects also, yet they would also effect the athletes ability to perform.)

Mod B with PM1 - Took into account the potential for variable drag and accounted for it with the "Drag Factor" calculation. Environmental factors now were accounted for with the machine, yet the athlete would still be effected. DF updated every 17 strokes. (Which is the reason for the rule stating "DF can be set, but not changed during the competitors row.)

Mod C began with the PM1 but then changed to the PM2 - More processing power, better recall capability, and DF updated every single stroke. (Changing the DF during a row would no longer make any difference, yet the rule remains.)

If setting the PM1 and PM2 for 500m and rowing to completion, the times would match at 1:55.0, either direction from there, the time discrepancy would grow, equally, but in opposite directions. How the watts were being calulated for a given stroke appear to be the same, though the boat speed (Pace) for that given stroke would vary slightly based on the conversion formula.

It has been shown quite thoroughly that varying the watt output over a distance could yield far different Avg Power for the exact same time to complete that distance, thus even pacing is the most efficient. The PM2 displays and avg pace and the appropriate avg power for that pace at the end of the piece. It sounds as if the PM1 may have displayed a more genuine avg Power figure, however the only time that it would match with the Avg Pace would be in the case of very uniform pacing, otherwise it would be off to the degree that the power input varied throughout the piece. As Nosmo points out, this is a descision that would have to be made by C2 engineers, and likely was. The confusion over the whole thing, as displayed by Johns observing large discrepancies may well have been why it was changed to the PM2 "Avg Power" method, as the figures will always match up, causing less confusion for those with highly variable power output during a piece and a penchant for trying to match up the figures that are in reality uncalculatable as single data points.

Cheers! Far too much time wasted discussing this topic, though hopefully there is a little more light than dark after having done so.

[johnlvs2run]

The confusion over the whole thing, as displayed by Johns observing large discrepancies may well have been why it was changed to the PM2 "Avg Power" method, as the figures will always match up, causing less confusion for those with highly variable power output during a piece and a penchant for trying to match up the figures that are in reality uncalculatable as single data points.

Cheers! Far too much time wasted discussing this topic, though hopefully there is a little more light than dark after having done so.

That is certainly another possibility, and sheds more light on the issue.

However, this doesn't account for what concept2 calls the "truncation" on the pm1 monitor. As Paul has pointed out, truncation means to leave off the decimals. Concept2 apparently truncated the instantaneous display, then used some adjustment (rounding up) to get the average pace. A quote from the pm1 manual:

"Truncation of Pace Display
In pace/meters units, the STROKE OUTPUT is a truncated number. In other words, a pace reading of 1:57 means that your actual calculated pace lies between 1:57 and 1:57.99. If your target pace is 1:57, you should aim for 1:56, especially considering the slower pace readings of the first few strokes."

Based on their definition, rowing at a constant 1:56 pace on the monitor should yield an average pace of 1:57 at the end of the piece (taking the start in account). In practice, the difference between the instantaneous pace display, and the resulting average pace, was more than this .01 to .99 amount. If I was rowing at a constant 1:56 on the monitor, the average pace should end up at 1:57.0 but would instead end up being 1:58 to 2:00.

The truncation (adjustment) works in the same manner (but inconsistently) regardless of the pace.

It is this truncation and adjustment of the internal conversion from watts to time/pace that I personally noticed the most in using the pm1 monitor. The adjustment was neither (1) limited to 1 second, nor (2) consistent, and it is this adjustment that I feel caused most of the difference between the time/pace outputs of the pm1 and pm2 monitors.

[Nosmo]

...though hopefully there is a little more light than dark after having done so.

Boy are you optimistic.

[PaulS]

...though hopefully there is a little more light than dark after having done so.

Boy are you optimistic.

That bad, eh?

[johnlvs2run]

the PM1 truncated the displayed pace rather than rounding like the PM2(+), so it could have been a 1:22.999 and still shown you what it did. The PM2 could have been a 1:24.49 and still shown you what it did, so what might look like only a 2 second slowing of pace over 10 years of aging may even been as little as 1.5 or as much as 2.5

Yes you are right about that.

If I'm understanding the rounding correctly, my 1:22 on the pm1 could have been anywhere from 1:22.00 to 1:22.99, due to the truncation, and my 1:24's ten years later on the pm2+ could have been anywhere from 1:23.50 to 1:24.49, a difference of 0.5 to 2.5 seconds.

Taking middle values as an estimate, 1:22.5 to 1:24 is a 1.5s difference, closer than I had thought they were.

[Nosmo]

Deeper into the abyss I plunge....

]
If I was rowing at a constant 1:56 on the monitor, the average pace should end up at 1:57.0 but would instead end up being 1:58 to 2:00.

John,
I finally understand why you are so insistent .
You say the display may read a steady 1:56 but rowing at this pace for 5K may yield a time of 20:00.0. If that has indeed been the case, there is indeed something much more seriously wrong then truncation error. I certainly have seen the 1 second per 500 discrepency but have not seen a 4 second.
The truncation is for the instantaneous display. The internal workings of the PM1 should be much more accruate. So if you are rowing a steady 1:59.9 for 5K, the display should say 1:59 the whole time but the final time should say 19:59.0. If it does not then this is not truncation error but either a major screw up in the PM1 firmware, or a faulty unit.

]
The pm2 does have the average watts. This is why I was able to calculate the average watts to time/pace mathematically, and the results came out the same as the internal conversion to time/pace every time.

John, if you learn one thing from this discussion you should understand that the reason you CAN convert from watts to average pace for a a piece with the PM2 is because it displays something different from average watts. If it did display average watts, you could NOT do the calculation. Go back and read my and Paul's previous posts, and if you understand them, you will see that the PM2 display is not "average watts" but rather something we could call "average pace equivelent watts", "cube of the average of the cube root of the watts", or "minium watts to row the measured average pace".

[johnlvs2run]

If that has indeed been the case, there is indeed something much more seriously wrong then truncation error. I certainly have seen the 1 second per 500 discrepency but have not seen a 4 second.

You currently have and are using a pm1? Remember the display is truncated. So the average as given by the pm1 was maybe 2 to 3 seconds different than this. I didn't normally see it be off by 4 seconds. If I happen to come across any of the notes that I made at that time I will post them.

The truncation is for the instantaneous display. The internal workings of the PM1 should be much more accruate. So if you are rowing a steady 1:59.9 for 5K, the display should say 1:59 the whole time but the final time should say 19:59.0. If it does not then this is not truncation error but either a major screw up in the PM1 firmware, or a faulty unit.

I think we can agree that the pm1 didn't do what you and I would expect or want it to do.

Paul's and my experiments were really different kinds of experiments. In my opinion, Paul's experiment was much more complicated than mine, and had a lot of variables to control. I don't even know very much about his experiment.

My experiment was very simple. All I did was to mathematically calculate the time/pace from the average watts at the end of each piece. This made it very easy to see how far off the (1) internally converted pace/time was from the (2) mathematically calculated time/pace as derived from the watts. This is something that anyone with a pm1 monitor could easily do.

The instantaneous pace on the pm1 was truncated but there were no other adjustments, it was in line and consistent with the watts display, and the internal conversion was not. Additionally, the instantaneous watts was in line and consistent with the mathematical calculation of the time/pace from the average watts display at the end of each piece. Thus there was something majorly haywire with the internal conversion - from - watts to time/pace on the pm1 monitor.

John, if you learn one thing from this discussion you should understand that the reason you CAN convert from watts to average pace for a a piece with the PM2 is because it displays something different from average watts.

The image on the right is the watts display on the pm2 monitor. The average watts are displayed in the lower left corner of this mode. These average watts are displayed continuously while rowing, and then at the end of the piece. My understanding from concept2 is that the time/pace on the pm2 (as with the other monitors) are computed from the watts.



http://www.concept2.com/us/support/moni ... level1.asp

If it did display average watts, you could NOT do the calculation. Go back and read my and Paul's previous posts, and if you understand them, you will see that the PM2 display is not "average watts" but rather something we could call "average pace equivelent watts", "cube of the average of the cube root of the watts", or "minium watts to row the measured average pace".

I'm not sure what point you are trying to make unless you are trying to say the watts come from the pace. However, hasn't concept2 made it clear that the time/pace is derived from the watts on all monitors.

[Gerhard]

You guys have too much time.....

[Nosmo]

The image on the right is the watts display on the pm2 monitor. The average watts are displayed in the lower left corner of this mode. These average watts are displayed continuously while rowing, and then at the end of the piece.

Yes I know this. They may call it average watts but it not an "average" of the instantaneous watts, in any common usage of the word average.

I think we can agree that the pm1 didn't do what you and I would expect or want it to do. ....

We can agree that the PM1 does something different from the PM2/3/4. We can agree that it does not do what you expect it to do, or what one would most obviously expect.
I think I understand what it does and why it does what it does, and I think it behaves as I expect it to. I do not expect average watts and average pace to agree on the PM1 for the reasons I've tried but obviously failed to convey.

I'm not sure what point you are trying to make unless you are trying to say the watts come from the pace. However, hasn't concept2 made it clear that the time/pace is derived from the watts on all monitors.

You misunderstood.

Think of it this way: If you do a 2K and pace yourself very badly, so that you start out too fast and slow down a lot then speed up and die at the end. You will get a poor time. If you then row exactly the same time but do it steadily it will be much easier.
In the first case you actually do much more work and burn more calories then in the second. You wasted a lot of energy in the first case. The PM1 average watts tells you how much work you actually did--even though some of it was wasted. It will give you a bigger average watts then it will in the second case, precisely because you did more work. Your time in both cases is the same because you wasted energy in the first case and not in the second.

The PM2 gives you the same "average" watts in both cases. (average is in quotes because it is not a conventional average). Neither way is incorrect, They are merely different.

BTW, I had a model B with a PM1 until September '06. Now I have a D with a PM3. I have little experience with a PM2 but have erged on one a few times. If I still had a B I would do the experiments necessary to confirm all this.

And we do have too much time on our hands.

[PaulS]

The woods are lovely, dark, and deep...

[Bob S.]

I sometimes wonder how Chad feels about how the thread he started has been hijacked into this endless three way discussion about out-dated performance monitors that almost no one really gives a damn about. The thread started out on a high note but rapidly deteriorated.

Bob S.

[johnlvs2run]

They may call it average watts but it not an "average" of the instantaneous watts, in any common usage of the word average.

It's the average watts for the whole piece to that point.

The PM2 gives you the same "average" watts in both cases. (average is in quotes because it is not a conventional average). Neither way is incorrect, They are merely different.

The pm2 average watts will not be the same in both cases. When you row inefficiently, the average watts and time/pace will be slower.

Regarding the time/pace watts, apparently you prefer the pm1 method more, while I definitely prefer the pm2 method more. To each our own.

Bob,

Chad can be well proud that he is seen as the highlight of this thread.

[PaulS]

Chad,

Those are fantastically great times, especially the 1:03's for 8 strokes in a row.

Leo Young did a 1:10.5 for 500 meters on the model B in 1991. Here is a quotation by him on the UK forum in 2005.

"The world record 500 metre time of 1:10.5 was performed in 1991 on a model B (the model C didn't come out until 1993)."

Leo also had a number of kayak world records. You can find more quotations from him here:
http://www.concept2.co.uk/forum/search. ... ults=posts

What are your secrets for success. Cheers for continuous improvements of your times.

Thank you John, this is the information I was interested in, I will aim to beat that 1.10.5 by Leo Young. I will see if I can record my efforts in video format and post online.

How does a model D compare to a Model B?

No secret to rowing the sprints John, I am very tall, heavy and am now also getting very strong, the 3 things I have found are ideal for erg sprinting.

In your pace range there is about a 3 second advantage built into the PM1 (over the PM2 or later). The 1:12.8 500m is very fast.

Make sure to get your Verification code, or a photo, or something. Well Done! A video of this sort of thing would be fantastic.

Now Bob,

There was a completely clear and concise answer to Chad's question in the first few posts. (as shown above) The deterioration of the thread has to do with communication, understanding, or other factors beyond our control.