Criterium Power Analysis

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Criterium Power Analysis

Postby Alex Simmons/RST » Mon Nov 10, 2008 5:19 pm

For a bit of fun and education, I thought I'd post a couple of criterium data files and open up for questions as to what it all means and what one can learn from it.

Here's one from the Brindabella Crit in Canberra.

In it I have marked where I did a solo break away (basically from the start), then was joined by another guy after 15-min. The total race stats are shown on the left, but note:

Ride Section___ Avg Power__ Normalised Power___ (NP/AP)
Overall Race____ 289W________ 306W___________ (1.06)
Solo Break_____ 322W_________ 331W___________ (1.03)
Two-man Break_ 269W_________ 288W___________ (1.07)

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by BNA » Mon Nov 10, 2008 5:22 pm

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Postby chris641 » Mon Nov 10, 2008 5:22 pm

Some nice power you got going there.

I've always wondered, but never got around to researching, what the normalized power numbers mean as opposed to the average power??
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Postby Alex Simmons/RST » Mon Nov 10, 2008 5:25 pm

And here is another one.

This time a State Masters Criterium Championships at Port Macquarie.

Duration: ___ 48:09
Work:______ 797 kJ
TSS:_______ 127.1 (intensity factor 1.258)
Norm Power:_ 352
VI:_________ 1.28
Distance:____ 29.914 km

____________Min___ Max___ Avg
Power:______ 0 ____ 1336 __ 276 watts
Cadence:____ 23 ___ 124 ___ 94 rpm
Speed:______ 0 ____ 49.8 ___ 37.9 kph


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Postby Alex Simmons/RST » Mon Nov 10, 2008 5:30 pm

chris641 wrote:Some nice power you got going there.

I've always wondered, but never got around to researching, what the normalized power numbers mean as opposed to the average power??

Normalised Power is a means by which the physiological strain of rides can be equated to one another.

It takes into account that the relationship between power and the strain on the body is not linear but curvelinear in nature (and follows a relatively predictable time course).

Hence, a highly variable power ride, while it may be of relatively low average power (compared to, say, what you could do as a solo TT like effort), can be quite stressful on the body simply because the high power surges take more out of you.

if you want to know more about it, have a read here:
http://www.cyclingpeakssoftware.com/pow ... efined.asp

and ask more questions.
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Postby chris641 » Mon Nov 10, 2008 5:35 pm

Alex Simmons/RST wrote:if you want to know more about it, have a read here:
http://www.cyclingpeakssoftware.com/pow ... efined.asp

and ask more questions.


Cheers, that's quite a good read, and very impressive how it is all calculated. I've been looking at getting myself a power meter so this could be quite handy.
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Postby toolonglegs » Mon Nov 10, 2008 5:36 pm

OK... i know you say HR is not very important when working with power...but an av of 113 and max of 124! :shock:
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Postby toolonglegs » Mon Nov 10, 2008 5:39 pm

These are both pre accident right?...just wondered what the difference in your max and av power is now...and what do you estimate it will be once you are fully fit again.
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Postby philip » Mon Nov 10, 2008 5:58 pm

Cool that's pretty interesting, especially the large differences in average power between the solo/two man break.

What can you determine by looking at one of these in terms of improvement? Can you look at it and say "I could've done X better and Y point in time", or do you only get a benefit by comparing one race with another to determine a change/improvement?
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Postby Alex Simmons/RST » Mon Nov 10, 2008 6:34 pm

toolonglegs wrote:OK... i know you say HR is not very important when working with power...but an av of 113 and max of 124! :shock:
I rarely wear a HR strap nowdays, so any readings would be erroneous pickups from other riders probably.

Indeed I don't even know where it is.
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Postby Alex Simmons/RST » Mon Nov 10, 2008 6:45 pm

toolonglegs wrote:These are both pre accident right?...just wondered what the difference in your max and av power is now...

Yes, pre-accident races. My leg was amputated in May 2007. I first tried to pedal on a trainer on 13 June this year.

Well compared to previous best able bodied tests, my tests about a month ago showed:
FTP:________ 240 / 315 watts = 76%
20-min MMP:_ 252 / 327 watts = 77%
MAP:_______ 355 / 399 watts = 89%
5-sec MMP:_ 1074 / 1471 watts = 73%

FTP = Functional Threshold Power = 1-hr TT power
MAP = Maximal Aerobic Power = 1-min mean maximal at end of a ramp test to exhaustion, ramping at 25W/min.
MMP = mean maximal power

toolonglegs wrote:...and what do you estimate it will be once you are fully fit again.

I don't know how far I can go but my ultimate aim to is to generate more power than I could before. That may however takes some years to do.
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Postby Alex Simmons/RST » Mon Nov 10, 2008 7:09 pm

philip wrote:Cool that's pretty interesting, especially the large differences in average power between the solo/two man break.

What can you determine by looking at one of these in terms of improvement? Can you look at it and say "I could've done X better and Y point in time", or do you only get a benefit by comparing one race with another to determine a change/improvement?

In terms of fitness progression, really you only look at race data (or a section of race data) when you know it was maximal effort. Otherwise tests are better for that.

You might actually learn more from races where you cracked, than where you went well.

Racing is often about how you rode as opposed to the absolute numbers. The power data tells you what you did, as opposed to what you should/could have done.

In the race where I was in the solo and then 2 man break, what I can say is that I was starting to suffer a bit after ~ 12-min or so (it was a very hot day with a shocking hot westerly blowing), so the power file reflects the point where you can see I eased up a bit as I noticed a guy bridging across and so I made the tactical decision to allow that to happen since I figured I had a better chance of making a break stick with two of us sharing the workload rather than solo in those conditions. By significantly dropping the power required to roughly maintain the same speed, we could maintain our break.

What I did learn is that, if executed well, I had the power to make a race go my way and have the confidence to execute such a strategy. So often we sit in the bunch and wonder what might have been.

This tells you what the actual demands are in order to execute such a strategy.

Ironically, in this case I didn't actually launch an attack in the usual sense. We hadn't even done one lap, the guy in front of me rolled off, I just put a little pressure on through a turn and there was a couple of bike lengths. I just kept the pressure on and the gap grew a little. The field would have thought (quite understandably), it's so friggin hot and windy, let the bugger fry.
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Postby toolonglegs » Mon Nov 10, 2008 7:10 pm

When you say this may take some years to do...why so long?.Because your fitness / muscle mass has fallen so much in the last 2 years (which would be no suprise) or also / or as well it will take your body that long to adapt.
Looking at the compared data they are obviously lower but you must be happy that they are not really that far off previous best considering you haven't been back riding for 6 months yet!.
I would be interested to see a graph from a training session as well (if poss with explanation) as that is a controlled setting where as a race you have no choice but to roll with the punches.
In the last few months I am noticing considerable improvements in my riding...mainly due to what you (and another coach from a not so reputable forum :roll: ) have been saying...as well as Greg Lemond :D .Intensity over endurance...Ok I am no where near where I was 3 years ago (before I had a 18 month virus and continuing sinus probs)but feel that if I can get over my biggest problem ie:weight!...I might be back in A grade one day!!!...on flat courses anyway.Dont seem to have many flat crits here.
So cheers!.
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Postby Alex Simmons/RST » Mon Nov 10, 2008 7:33 pm

toolonglegs wrote:When you say this may take some years to do...why so long?.Because your fitness / muscle mass has fallen so much in the last 2 years (which would be no suprise) or also / or as well it will take your body that long to adapt.
Looking at the compared data they are obviously lower but you must be happy that they are not really that far off previous best considering you haven't been back riding for 6 months yet!.
I would be interested to see a graph from a training session as well (if poss with explanation) as that is a controlled setting where as a race you have no choice but to roll with the punches.
In the last few months I am noticing considerable improvements in my riding...mainly due to what you (and another coach from a not so reputable forum :roll: ) have been saying...as well as Greg Lemond :D .Intensity over endurance...Ok I am no where near where I was 3 years ago (before I had a 18 month virus and continuing sinus probs)but feel that if I can get over my biggest problem ie:weight!...I might be back in A grade one day!!!...on flat courses anyway.Dont seem to have many flat crits here.
So cheers!.

Well I can't say what all the reasons are, other than I know the more serious the injury, the longer the recovery takes. I count losing my lower left leg as reasonably serious injury. As well, improvements in aerobic fitness can be continued for several years and I did not consider I had reached a peak before my accident.

Finally, most of the amputee cyclists I have discussed this with have said it takes ~3 years for the stump to settle down. My ability to train is hence limited to a large extent by the ability of my stump to cope.

Here is a sample of a TTIs (threshold tolerance intervals), or the classic 2 x 20 intervals set I did 2 weeks ago. These were on my indoor ergo bike.

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Here's another session. This time a 45-min hard tempo effort at 97% of threshold, followed by a 15-min steady effort then some 30-second Lactate Tolerance Intervals.

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Postby Ant. » Mon Nov 10, 2008 7:52 pm

Cool files.

I don't even know enough about power to ask questions, apart from: Why do you have cadence measured on your indoor workouts but not on your outdoor?
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Postby thepj » Mon Nov 10, 2008 8:02 pm

i amazed that it shows how much toruqe you crank out. how does it work that out?
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Postby Alex Simmons/RST » Mon Nov 10, 2008 8:24 pm

Ant. wrote:Cool files.

I don't even know enough about power to ask questions, apart from: Why do you have cadence measured on your indoor workouts but not on your outdoor?
I can choose what data is displayed.
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Postby Alex Simmons/RST » Mon Nov 10, 2008 8:29 pm

thepj wrote:i amazed that it shows how much toruqe you crank out. how does it work that out?
Most power meters use a form of strain guage that measures the forces being applied to either the hub or the crank/spider.

It samples the forces at a rate between 60Hz and 200Hz depending on the type of power meter. That data is converted to a torque measurement, which is averaged over a period and multiplied by the rotational speed of hub or crank (depending on where the strain guages are) to give you a power number.

Data is then transmitted to and stored in a CPU for on bike display and later download to a computer.

The leading brands are very reliable and if calibrated properly, accurate and precise.
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Postby thepj » Mon Nov 10, 2008 8:36 pm

ok kool pretty interesting. thanks for info
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Postby toolonglegs » Mon Nov 10, 2008 9:23 pm

Thanks Alex...so the choice is warm clothes for winter or power meter...looks like i will be a bit cool this winter :lol:
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Postby sogood » Mon Nov 10, 2008 10:44 pm

Alex Simmons/RST wrote:You might actually learn more from races where you cracked, than where you went well.

So you won in that first example and did not crack, does that mean the data did not show your limits, and is not that useful in isolation? To make it more useful, would you primarily compare it with your past data, especially on the same course? And in relation to cracking, would the idea be to use the power data to identify your physical limits and specifically the condition under which you reached your limit, and then tailor your future training with that specific focus?
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Postby Alex Simmons/RST » Tue Nov 11, 2008 7:44 am

sogood wrote:So you won in that first example and did not crack, does that mean the data did not show your limits, and is not that useful in isolation?

Well on that day, in the solo break I was at my limit (for those conditions - very hot and very windy) and the sprint was a PB for sprint power. So that tells me something.

sogood wrote:To make it more useful, would you primarily compare it with your past data, especially on the same course? And in relation to cracking, would the idea be to use the power data to identify your physical limits and specifically the condition under which you reached your limit, and then tailor your future training with that specific focus?

Well that has been the only time I've ridden that particular course. But yes, depending on the race, it can be very helpful. For example, if one were going to race on that Port Macquarie crit course, what sort of training do you think might be needed if your jump isn't all that great?

To an extent, one can see in what way they cracked but it takes a bit of considered thought to understand why. Some may consider it a lack of anaerobic abilities, when it might actually be poor aerobic condition.

In the end, it's still an aerobic sport and so the primary need is to develop our aerobic engines. Nevertheless, if there are patterns of cracking, e.g. you go out the back door after 3-4 big surges (which are quantified by the PM), then it tells me that your abilities at coping with such circumstances could use some attention.

What can be interesting is to compare power data from two similar sized riders from the same race. You can spot the smart rider, who conserves his energy as much as possible and then when the hammer goes down, they really nail it, hard.
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Postby ni78ck » Tue Nov 11, 2008 8:03 am

toolonglegs wrote:OK... i know you say HR is not very important when working with power...but an av of 113 and max of 124! :shock:


+1
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Postby Alex Simmons/RST » Tue Nov 11, 2008 8:08 am

ni78ck wrote:
toolonglegs wrote:OK... i know you say HR is not very important when working with power...but an av of 113 and max of 124! :shock:


+1

I answered that. I didn't wear a HR strap so it was just erroneous readings.
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Postby ni78ck » Tue Nov 11, 2008 8:15 am

Alex Simmons/RST wrote:
ni78ck wrote:
toolonglegs wrote:OK... i know you say HR is not very important when working with power...but an av of 113 and max of 124! :shock:


+1

I answered that. I didn't wear a HR strap so it was just erroneous readings.


oops, i was going through it and quoted prematurily!

i did not know you were an amputee, your efforts are nothing less than incredible. the fact that you are so competitive in racers is fantastic and an inspiration to me, and i guess all of us :wink:
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Postby Hebden » Tue Nov 11, 2008 9:52 am

Thanks Alex, really appreciate the sharing of knowledge and experience.

Are your watts displayed live while you cycle? Or is the data mainly used for post workout analysis?

For instance would you train within a watt zone, like HR Zone training?
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