Using speed instead of power?
Gav888
Posts: 946
Hi,
Ok, ive been reading up on power, and training etc today and ive come up with a possible work around that may or may not work, so im posting it hear to gather your thoughts.
At the moment I only have a hrm and sadly no plans this year to buy a power meter, but I still want a way of making sure im using the right intensity when doing interval training.
At the moment if im doing a 60min hr zone 3 tempo workout on the turbo, its taking approx 15min to get my heart rate into zone 3, so until its there I cannot judge how hard I should be pedalling. That 15min could be too high, or too low which is why its taking ages to get to zone 3, also for vo2max intervals, you cannot use heart rate as these are normally 4 - 6min long and heart rate is too slow. From my understanding heart rate is good for long rides, say 30min or longer but short intervals power is best.
So ive been thinking that the power community refer to levels as CP3, CP6, CP12, CP20, CP30, CP60, CP90 etc, and CP60 being your FTP.
So, my understanding (please correct me if im wrong) is CP60 is the highest power output you can maintain for 60min, and CP20 is the same but for 20min, CP3 is 3min and so on. If thats the case, if I ride max effort for 60min and record my average speed that speed would effectively be my CP60 speed, of FTS - Functional Threshold Speed?
Obviously this would only work on an indoor turbo training or rollers as there are too many variables outside to use speed, hills, wind, etc etc but when using a turbo it should be a good estimate shouldnt it?
If so, I could then use power zones, such as these http://www.trainingbible.com/joesblo...ing-zones.html replacing the power at CP60, with my average speed to work out approx speeds to achieve for each level of effort. Then when I do say a 20min interval I make sure im going at my CP20 speed?
With regular CP60 tests I could monitor my new speeds as I get fitter?
Does this sound right?
Ok, ive been reading up on power, and training etc today and ive come up with a possible work around that may or may not work, so im posting it hear to gather your thoughts.
At the moment I only have a hrm and sadly no plans this year to buy a power meter, but I still want a way of making sure im using the right intensity when doing interval training.
At the moment if im doing a 60min hr zone 3 tempo workout on the turbo, its taking approx 15min to get my heart rate into zone 3, so until its there I cannot judge how hard I should be pedalling. That 15min could be too high, or too low which is why its taking ages to get to zone 3, also for vo2max intervals, you cannot use heart rate as these are normally 4 - 6min long and heart rate is too slow. From my understanding heart rate is good for long rides, say 30min or longer but short intervals power is best.
So ive been thinking that the power community refer to levels as CP3, CP6, CP12, CP20, CP30, CP60, CP90 etc, and CP60 being your FTP.
So, my understanding (please correct me if im wrong) is CP60 is the highest power output you can maintain for 60min, and CP20 is the same but for 20min, CP3 is 3min and so on. If thats the case, if I ride max effort for 60min and record my average speed that speed would effectively be my CP60 speed, of FTS - Functional Threshold Speed?
Obviously this would only work on an indoor turbo training or rollers as there are too many variables outside to use speed, hills, wind, etc etc but when using a turbo it should be a good estimate shouldnt it?
If so, I could then use power zones, such as these http://www.trainingbible.com/joesblo...ing-zones.html replacing the power at CP60, with my average speed to work out approx speeds to achieve for each level of effort. Then when I do say a 20min interval I make sure im going at my CP20 speed?
With regular CP60 tests I could monitor my new speeds as I get fitter?
Does this sound right?
Cycling never gets any easier, you just go faster - Greg LeMond
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The big proviso is making the conditions repeatable each time - it's best if you can leave an old frame set up on the turbo rather than keep setting your road bike up on the turbo (assuming you are also using it outdoors at weekend). You also need to make sure your tyre pressure is consistent.
There are a few problems though:
- if you change any of the conditions (roller pressure on tyre or rolling resistance with a new tyre) you have to work out your "zones" from scratch - you may be able to use a "roll-down test" to try to calibrate things (timing how long the wheel takes to stop from a known speed)
- ambient temperature (and hence rolling resistance) can be hard to account for
- it's very difficult to relate "levels" to each other - a 10% increase in speed may not equal a 10% increase in power
I had the same problem as you this time last year. I wanted to do intervals in a controllable way and use them to measure progress. I though about it and tried going down the turbo route but ended up instead using a local road with no stops and doing loops of that for long intervals and using a short hill for short intervals. I was flexible with my training days so that I could do my key intervals when the weather was good. Then when I'd had a guts full of the wind messing up the results I'd saved enough credits to buy a power meter.
You seem keen to get a good structured training plan with a bit of accuracy thrown in, at the end of the day if these are your aims then bite the bullet and either get or save up for a powermeter. Honestly it's worth the investment and takes out a lot of the questions you are asking. Not that there's anything wrong with your questions.
Bronzie's advice is good. What it comes down to is finding at which speed you can do the various sessions for the different zones you're targetting. Use your HRM to judge whether you're under or overcooking it, by experience. If you do a training session 5 times at the same speed and each time your HR ends up higher than it should, then you've obviously chosen a speed that's too high. That's all there is to it.
Ruth
As others have said, there's no problem with using speed as a proxy for power, many turbo manufacturers even publish the power curves of their trainers, but as others have also said it's sensitive to set up and tyre pressures.
Your biggest likely problem is in finding the relevant speeds that aren't your tested CS 60, since the speed will differ by a different amount than power does. i.e. 10% slower speed might be 95% of the power and 30% of the speed 65% of the power. ie the turbo has a curve, not a linear relationship.
Testing and training is better than just random testing and the simple rewards of seeing a number increase will likely help you more than anything else.
Conditions are generally the same, the only thing that wouldnt be is a few degrees temperate difference between winter and summer, I use the same bike, check the tire pressures every other session, fan is set to the same speed each time, and the turbo is a Elite Crono Fluid so resistance is via the gears on the bike. Say that, ive just remembered there is a small plug on the side of the resistance hub that you can plug something in, do these turbo's have an optional power meter?
I will keep an eye out for a 2nd hand power meter, didnt think of that, but I feel I will need one sooner or later as I do like looking at data
You've got the same turbo as me, only mine is the digital version with a head unit that displays speed, distance and something they call power. I'll have a powertap soon so I'll know for sure, but I think the resistance varies quite a bit with temperature (mine is in the garage).
No I'm not suggesting that. I'm suggesting that if you keep on asking questions about using speed as a proxy for power then eventually you'd be be better off 'biting the bullet' and buying a power meter.
Don't want to make excuses but that race brings back memories. Don't want to lay a guilt trip on you but iirc that race was two weeks after I came out of hospital after a lung operation.
In that year I'd had two minor strokes and two lung collapses (not good when you're in your early 30's with two great, young children). That operation cured the lungs and I cured the stroke problem. That was the last time I've been to hospital and that race was the end and start of a new life phase for me. Happy memories for me finishing and you battling my club mate. I've got a tear in my eye now.... :oops:
and Welsh 12hr is in July this year if you fancy it?
Ruth
Interesting... once you have the powertab it would be interesting to compare the data from the turbo to see how accurate it is....
Sorry, I did ask about this a while ago but back then I had little knowledge of training and I didnt have a turbo. Now I have a turbo and although speed isn't power it gives me a rough idea of what speed to hold for a specifc zone / period / interval.
No offence caused at all
Besides every defeat is an inspiration to train harder and it's good to be reminded when you're soundly beaten by a girl.
and Gav; I have no problem with you asking it and re asking it. It's a good question and if speed could be used as a reliable proxy for power like you suggest then it would save a lot of people a lot of money.
FFs, I've said that and I can't even remember what the question was now, I've got so much water in my eye.
I used rear wheel speed only last winter and went from doing 2x20's at 19.0mph to 21.5mph over a period of about 10 weeks. I have an old bike that I keep setup on the turbo in the garage so apart from checking tyre pressure each time, nothing much changed between sessions apart from ambient temperature.
Thats interesting to see what speed you can do for 2 x 20's, it gives me something to aim for
Just in case you weren't being sarcastic etc. 21.5mph on a turbo set up for someone else is completely different to road speed. 21.5mph on a turbo does not equal 21.5mph on the road (for what is's worth it's usually quite a bit higher on the road but thats besides the point) speed is completely different to power, here endeth the lesson.
But did it help you win races?
I have to be honest I find it very very difficult to get motivated to get my censored on a trubo, end even worse to do anything worthwhile when on it
I do howevr intend to bite the bullet and do simulated track sessions on it. Shorter harder intervals etc, 3km efforts etc.
I would go insane doing 20 x 20
How you guys manage this is beyond me
http://www.youtube.com/watch?v=aK5Bfqj5fxY
Nice gap!!! well done, I take it the guy pulling off couldn't keep up
Reppohkcor, yep I was being sarcastic as I know speed on a turbo is different to the road, and speed is different from one turbo to another but its something to aim for
Product manager, Sports
iPlayer!
Alex - is that a regular able-bodied crit? If so, makes it even more impressive!
My question was specifically for Rich, not for everyone
Guess I will find out tomorrow when he is on the reliability ride.
http://www.youtube.com/watch?v=aK5Bfqj5fxY
I attacked early on for about 4 laps but my partner wasn't able to contribute sufficiently to make it stick, so I just rolled with the group and waited, launching my attack over the second pimple into the NE wind (about 600 metres to go). They all just looked at each other thinking I was going way too early. I knew better given the wind on that day.
Jeff of course knows the circuit very well, and that is an attack just before the final technical part of the circuit leading onto the 400m long straight.
NP for the ~48min was 287W
Australia Day crit Tuesday, that won't be quite so "easy".
I think that this is the bottom line. If you can reduce the variables as much as possible (some very good ideas already given) then I think that you can use rear wheel speed on a turbo as ONE of the ways to HELP you gauge the intensity of your workouts (along with RPE and HR.) It has obviously nowhere near the accuracy of a power meter, but then if you can't afford a power meter then that's a moot point anyway.
I still don't have the powertap, but here's one example of why I'm sceptical about the repeatability on my Elite fluid trainer:
Friday: 20min near-maximum effort, average 'power' = 330W (this is almost certainly an overestimate
Sunday: 60min fairly comfortable, average 'power' = 323W, average speed from Garmin 31.5km/h, average heart rate = 141 bpm (81% of MHR, range 78-85% MHR)
Tyre pressure was the same, warm-up was the same. So based on these sessions, my avHR to maintain 31.7km/h for 20 minutes is about 161bpm, but I can maintain 31.5km/h for 3 times as long at an avHR of only 141bpm :?
For both sessions my cadence/speed drift upwards throughout (as the unit gets warmer and the resistance falls away) with no increase in RPE.
So what this actually tells me (something I've known for a while) is that if I do intervals then unless I progressively increase the speed that I do them at they're actually getting easier. The speed may be useful for comparing the same session, but as an accurate proxy for power its pretty useless.
Thing is, when you find out you've been fitted with a 1.0L 3-cylinder diesel engine instead of the 3.5L V6 turbo you ordered, then you better get good at engine tuning.
Thrashing myself silly on the turbo 4 nights a week certainly isn't making me go any slower, that's for damn sure.
Good luck on Tuesday!
(Sorry to take things OT but it's good to see you win)
Product manager, Sports