PDA

View Full Version : Metrics



Dura-Ace
10-20-2009, 04:40 PM
Does anyone have any wattage metrics. I saw on the RoadbikeRider news letter

"Sure, pro bike racers can do things we only dream of:, average 450 watts on a 30-minute climb."

Does anyone have any other such metrics. These are great for getting my class to focus on the watts and not the miles on the M3's.

Todd S
10-20-2009, 04:55 PM
This is pretty much the gold standard.

http://home.trainingpeaks.com/articles/cycling/power-profiling.aspx

liveon2wheels
10-21-2009, 06:21 AM
I've spent the last 15 months working on the Keiser M3 trying to make sense out of the power numbers as they relate "to the rest of us". I've followed the trainingpeaks folks, reading Hunter & Allen's book several times, and following countless discussions on the wattage forum. I've done metabolic testing on M3s and kept track of power numbers as they relate to a host of biological markers - across a deep cross section of "normal folk". These range from indoor only folk to the group of local racers. However, the best racers are still not "elite" cyclists - cat 3 is the highest on the road, and we have many winners of local MTB races, but no NORBA competitors. I say all that to tell you that there are two different worlds of outdoor cyclists, and the folks that frequent trainingpeaks are typically of a much higher caliber in ability (and possibly wealth - power meters are not cheap) than most.

I've recently sent for three charts that we will be selling soon to help establish Power Zones, and that will illustrate the power needed to climb outdoor hills based on the grade of the hill and the speed of the rider, in watts/lb (instead of watts/kg, which the rest of the metric world uses).

This forum is not appropriate for me to go into detail, but I still think it is a useful to the readers to let them know another option is coming. While it may not be the current gold standard, it is targeted specifically to the clients most of us serve.

Robert
10-21-2009, 09:50 AM
Be careful if proposing to use the M3's power reader - it's as inaccurate as its "odometer" and is not a power-sourced calculation. It also varies from bike to bike and, if testing on one bike, it may not be the same reading in a few months' time.

I.e., if you test your FTP on one bike as 350W, you may struggle to get beyond 150W the next ride. Likewise with the "gears" - some bikes I've been unable to raise beyond gear 8, whereas most others, I can easily reach 20.

liveon2wheels
10-22-2009, 04:11 AM
Be careful if proposing to use the M3's power reader - it's as inaccurate as its "odometer" and is not a power-sourced calculation. It also varies from bike to bike and, if testing on one bike, it may not be the same reading in a few months' time.

I.e., if you test your FTP on one bike as 350W, you may struggle to get beyond 150W the next ride. Likewise with the "gears" - some bikes I've been unable to raise beyond gear 8, whereas most others, I can easily reach 20.
My experience is COMPLETELY opposite to this. I've validated indoor and outdoor power within 10%. Yes, to the folks at trainingpeaks, this would be highly unacceptable, and too inaccurate to train with. However, for the vast majority of the population I teach, this still gets them close enough to use the system to train themselves towards sufficient power to climb outside. I've take folks that have to get off most hills over 6% to being able to handle 9 to 11 per cent climbs. The difference in watts is substantial, and without the Keiser M3s, they would still be walking their bikes up those hills. Sounds like you've experienced a facility that doesn't keep up with maintaining their bikes.

By the way, I've also done comparative tests with my competitive racers (MTB and Road), and both have had similar, within 10% results, so there doesn't seem to be a reliability problem from my experience.

Robert
10-22-2009, 06:37 AM
Sounds like you've experienced a facility that doesn't keep up with maintaining their bikes.

The bikes were brand new! I rode one at gear 20, which felt the same as gear 25 on another and yet another bike I was unable to go beyond gear 6.

As for the power readings, if they are accurate to even within 10%, I should be a pro by now, as I can churn out a FTP of 450W. At 300W my HR isn't even 60% HRR.

Todd S
10-22-2009, 10:54 AM
My experience is COMPLETELY opposite to this. I've validated indoor and outdoor power within 10%.

How? M3s can't be calibrated.

...and even if they are within "10%", do you realize how large a range that is in practical terms? A 5% correction is the typical rule of thumb for estimating the difference between a rider's 20 minute and 60 minute maximum sustainable power levels. When operating near threshold, inaccuracies of 5 - 10 watts make a big difference. Your numbers could easily be off by more than twice that.

Please just take this as constructive criticism, but you're measuring performance on a device with questionable accuracy at best and measuring metabolic responses with a cart that also has a reputation for being notoriously inaccurate. The only thing you're measuring accurately is HR, and that is only loosely correlated with performance and metabolic responses. I admire what you're trying to do but your numbers ???

Power is a revolutionary training tool for those looking to optimize performance, but the less fit the rider the greater the fitness gains you're apt to see just through regular training and the most basic tools.

liveon2wheels
10-23-2009, 05:42 AM
The bikes were brand new! I rode one at gear 20, which felt the same as gear 25 on another and yet another bike I was unable to go beyond gear 6.

As for the power readings, if they are accurate to even within 10%, I should be a pro by now, as I can churn out a FTP of 450W. At 300W my HR isn't even 60% HRR.

These are indeed CRAZY numbers! If my experience was anything like that I would have either sent the bikes back or sent Lance a letter offering my services. I actually emailed the company yesterday to ask if they had heard of any issues of reliability since we really didn't have any. They confirmed that their first generation bikes had some "magnet drift" or something like that which caused some variation, but that their current models (which we have) were corrected. So, I can now understand your comments. I too would have not been able to work with those had that been the case.

liveon2wheels
10-23-2009, 05:51 AM
How? M3s can't be calibrated.

...and even if they are within "10%", do you realize how large a range that is in practical terms? A 5% correction is the typical rule of thumb for estimating the difference between a rider's 20 minute and 60 minute maximum sustainable power levels. When operating near threshold, inaccuracies of 5 - 10 watts make a big difference. Your numbers could easily be off by more than twice that.

Please just take this as constructive criticism, but you're measuring performance on a device with questionable accuracy at best and measuring metabolic responses with a cart that also has a reputation for being notoriously inaccurate. The only thing you're measuring accurately is HR, and that is only loosely correlated with performance and metabolic responses. I admire what you're trying to do but your numbers ???

Power is a revolutionary training tool for those looking to optimize performance, but the less fit the rider the greater the fitness gains you're apt to see just through regular training and the most basic tools.

At the end of the day, it's a matter of facts and results. You can mathematically derive how many watts per pound you need to carry yourself and your bike up a given hill, at a given grade, at a given speed. If you can then use these tools to train yourself to generate those watts, where you previously had not tools to do that, then this is a good thing. This is helpful, productive, and compared to most programs, pretty darn progressive.

Can you achieve results without tools - of course, men and women have been doing it for years. However, when you discover tools and methods that deliver results faster and more reliably than using no tools, then it makes sense to share it. Even my students who regularly race our local MTB and road races can't afford full power meters and all the training tools the folks on the wattage forum use, so for them, these tools are a welcome addition to their training. Affordable and effective.

Dura-Ace
11-11-2009, 10:30 AM
Is it just the M3's then or are the same arguments being made for the cycleops and the new Schwinns with power. I love being able to put metrics to class, and even with questionable accuracy is it really any worse than RPE and HR. I have really enjoyed the M3's but must admit I don't float from bike to bike and run comparisons.

liveon2wheels
11-12-2009, 06:19 AM
I've heard that the cyclops calibration process can be cumbersome, but I do not speak from experience - only trying to answer your question on whether you would hear negative chatter for other power bikes. The Schwinn's haven't been in the market long enough, but soon they will get their share. Negative talk has an uncanny way of surviving and floating among forums - it's human nature. None of these bikes will measure power like the SRM or PowerTap - they simply don't have the electronics and engineering. Unless you are Olympic level, I think it's a moot point. We are coming from a state of ZERO training tools on most indoor bikes, to having everything including power. For me, I think it's exciting, and extremely helpful.

Todd S
11-12-2009, 10:15 AM
I've heard that the cyclops calibration process can be cumbersome, but I do not speak from experience

If it's like the PowerTap hub on which it's based, it's not 'user calibratable'. The user does however have the ability to verify the calibration by hanging a known weight from the pedal spindle and verifying the accuracy of the displayed torque. If it's off, it's back to Saris for re-calibration.

Robert
11-12-2009, 11:06 AM
I understand that both CycleOps and Schwinn use PowerTap-style technology, unlike Keiser's mathematical estimation of power.

Then again, I think that's reflected in the price difference!