Wednesday, February 3, 2010

Elevation gain, power output.... ?????

Wow, as I clicked "New Post," I noticed this is blog #100. What a milestone. Haha ;)

So, I'm getting annoyed with all these devices that measure elevation gain. Before I get into it, let me preface this by saying: I don't really care how many feet I climb per se, hard work is hard work; however, I'd like to gauge my routes (running or riding) relative to the races I'm doing. Also, it's nice when someone says "I climbed 6,000 ft today" to be able and put that in perspective of what I do. So if I'm invited on a ride like that, I kind of know what to expect.

That said: Garmin, the iBike and online tools all give me VERY different numbers. I wouldn't care if the difference was only 100-300 ft, but 2,000-3,000 ft of difference is significant. Meanwhile, all the other stats match up: total miles, avg/max mph, etc. On Saturday's ride, we rode ~55 miles on what I consider a hilly route. The Garmin said 5,200 feet of elevation gain, the iBike said 3,200 feet. Entering the route online gives even bigger numbers... like 6,000 ft+ (

One thing I know about the iBike is this: Apparently, it only adds up what is considers "climbing," not just gradual elevation gains. Don't ask me how it does that, but in that little device it decides what a hill is and will add those feet up, but it doesn't care if you're on a 2% incline for 10 miles--those feet are ignored. Read more on that here if you wish.

But, really, a 2,000 ft difference between Garmin and iBike? I wonder what a PowerTap or SRM or whatever else there is would say??

A lot of people say the Garmins are full of it. Ian said he gained 1,000 feet of elevation on a trainer session in his living room. Classic! Others say the elevation changes as it sits on a desk. I have a Garmin Forerunner 405, and if it's been overestimating, then at least it makes me feel like a champ for climbing that much! :)

What are you guys using? And how much do you trust your device?? Do you compare stats with your training partners? I want a comment from James on this topic, because he seems to be the most dialed-in blogger out there! :)

AND: What device are race directors using to tell us the elevation gain in Ironmans, 70.3s, running races, etc? How accurate are their devices? Like I said in the beginning... really, all I want to know is if the training routes I ride/run are the best for my races this year. If they're "weak" then I'm ready and willing to step it up!!!

Switching gears a little... what about POWER?

Ah, power = work/time, also, = force x velocity. Basically, how fast can you get your @$$ (and its mass) to cover X miles? Spin faster, apply more torque!

I'm using the iBike, and I'm sure it's not a "perfect" device (is there such a thing?), but it was a lot cheaper and at least gives me something to work with power-wise as I set out to become a better cyclist. One thing I was told: even if the watts aren't exactly right on, the iBike is consistent--and that's important in measuring progress (or the bad days, ugh).

I know guys are animals and can drop some big watts. But I want to know more about women aka my competition! (All in good fun, of course.)

SOOOO MY QUESTION TO THE LADIES: I'm curious what sort of watts women around my age and/or ability level get on their rides. If you're a girl and wouldn't mind telling me some of the watts you're putting out, I'd appreciate it. (Send me private emails or FB messages if you wish.) Maggs, I saw on your blog that you have a PowerTap... talk to me pleeeease!

I read that for women, holding 3 watts per kg body weight is considered good. For me that's 180 watts (I weigh 60 kg).

I also read an old Triathlete Mag article where Linsey Corbin is said to hold 265 watts in a 40k TT and 210 watts over 112 miles. And she weighs like 120 lbs (~54 kg). Daaaamn, that's good! Same article: Tyler Stewart held 228 during ironman Florida 2007. Wow. I won't even get into the watts that the best guys are putting out.

As far as my watts so far--I don't really want to tell you guys my numbers just yet because it seems like I need to work on increasing my power :) But that's going off what the iBike says; I wonder how accurate it is? Would a PowerTap or SRM tell me something different? Too bad I don't have the money to do that experiment!

Last but not least: I know it's not "all about the numbers." But I believe this sort of data will help someone become a better athlete, and I'm trying to become better educated on these things so I can help myself and OTHERS. In the end, it's all about implementing the right training if you want to become a better athlete. Intensities, the routes on which you train, volume, rest, frequency, etc, etc, etc.


  1. great thing you've jumped on board the power train! once on it there is only one end/direction, SRM :)
    the wise person minimizes the in-between steps...
    but in "all seriousness" regarding your question I think that with your devices Garmin would give you the closest to truth readings. How close is that? Hard to say. I think SRM gives very close numbers as well as a Suunto HRM (usually difference with those 2 is 2meters at max)
    Regarding watts for women I think I can chime in as my chemistry up until recently has been more similar to a woman :) my 1h power has been about 275-310 depending on time of the year.
    But probably the best advice I can give is to observe how numbers spin relative to yourself. And to remember that training devices are good servants but extremely bad masters!
    Just enjoy the training and let numbers happen

  2. oh yeah and congrats on getting to the new "century" :D

  3. "Spin faster" - actually, spin slower. You'll generate more power at a lower cadence, for a given HR.

  4. If I'm going out for an endurance ride and don't want to kill my legs early on, I stay around 200 for the climbs. This is actually hard to do since the guys all take off and it would be about 350 to stay with them. But I actually descend a lot better than some of them (because I will also push about 160-180 down hill where they just coast). By the end of the ride when the hills come up, I'm usually right there next to them, still pushing only 200 watts up the hill. I take the same approach to racing with watts. I LOVE passing guys on the downhill. I love passing them on the uphill too, but passing them on the downhill usually means I'm working less than they did to pass me on the uphill.

    I also use watts and heart rate to determine what's going on. For instance, 3 weeks ago we did a practice time trial. My heartrate would not go above 160. And my watts were low. This told me I was tired (which I knew). And during a ride if I'm struggling to put out watts even though I'm working hard, i will look at my heart rate. Do I need to eat more? Drink more?

    I'm a fan of using the data to determine what I can do over the raw test data. For races I usually look at the last months data and compare it to my recent tests. You can learn a lot about what you should be able to do in a race by looking at what watts you held for how long in training.

    The big thing to remember when comparing watts is 1) the watt/weight, especially when climbing and 2) After the initial 100 or so watts to get you moving, a lot more watts does not really mean moving a lot faster. Meaning someone who putts out 400 watts in a time trial is not going twice as fast as someone who putts out 200 watts in a time trial.

    I'll email you some of my numbers, I need to look them up to make sure I have them right.

  5. Ryan,

    To a certain extent, what you said is totally true. But if you look at the "force-velocity curve," peak power is reached at 30% of your max velocity, so beyond that velocities that are too high or too low means power suffers. You must, of course, consider the athlete's abilities too. A big gear for me is likely different for you.

    Putting this in perspective: If someone's warming up to hit in baseball, studies show using a heavy bat results in the slowest bat swing performance as a opposed to warming up with light or normal-weight bats. Can that be related to bike gears? Maybe.

  6. Maggs,

    Thanks SO much for the info! Exactly the sort of stuff I want to hear about!

  7. I was using the Garmin 405 as well. I can't believe it is anywhere near accurate. I would hope the iBike is better. I hope don't use a Garmin to measure courses, something tells me they are more advanced than that. (But that "something" could be blind hope.)

    Can't chime in on power cuz I ain't gots one. Santa apparently didn't hear my SRM wishes

  8. my SRM does pretty well with elevation, i just have to make sure I have the starting elevation programmed in before i start rides to get everything accurate. my 405 has also been very accurate in reading out elevation within 50ft or so.

  9. Blah, blah, blah... bike stuff sucks. Your next post will be about running. Tyvm.

  10. I have no useful information for you, but I would LOVE to train with power!!! However, it's pricey and I work in the running industry... not the biking industry :( I hope you can ride with me next Friday for a bit, that would be AWESOME!

  11. Oh and in my research before buying a powertap, I asked a lot of questions. My local bike expert has ridden with the iBike, powertap, SRM and all the rest of them. He said the iBike was fairly accurate, just a little bit more of a pain in the butt to set up if wanted to switch bikes etc. But when he compared them he was always 3% off (low I think). And all that matters is the consistency so you know what you train at. Who cares if 250 is really 260? As long as you do your workouts/races at what you know as your efforts it doesn't matter.

  12. I stumbled across your blog and thought I'd throw in my two cents (or maybe a bit more).

    There is a google group "wattage" where they dive into a lot of power meter questions. The only downside is that you can get drawn into the seemingly endless debates.

    I just got a Quarq (SRM is out of my price range). I'm testing the power readings against a powertap and a computrainer. One would assuming that the quarq would read a little higher than the PT/CT but my informal study isn't near completion. Inital results show them close when properly calibrated/zeroed.

    Most importantly, I think, is using your data as MM says to show progress, what is going on with you physically (when you power doesn't correlate to RPE/HR) and using it to drive your training. As long as the data is consistent, that works great. Then you can work on bumping up your FTP and w/kg. That's a whole different debate :)