Short time trials

[email hidden said:

"]Malcolm Firth has pointed out that, as a consequence of the relationship between power and speed ( which is approximately cubic) it is ideal to time trial at constant power. I have significantly improved my times using this suggestion. I monitor my power on an SRM. However on short time trials (in Salt Lake City we have one by the lake which is 6.8 miles long) my results have not been that good. I can sustain about 311 Watts for 20 mins (on a good day). I weigh 185 lb. When I maintain constant power it takes a considerable time to reach stable velocity presumably due in part due to my large mass.At the turn around I have another slow acceleration. Since a slow acceleration occupies a relatively large proportion of a short trial would it be better to go, for example, for a minute at a power significantly above 311 Watts and then sustain 311 Watts? The time trial usually takes me close to 16 mins and I would like to take 30 secs to a minute off this. In short can an initial burst of effort to get up to speed quickly compensate for the inevitably reduced sustainable power.

Bridge,

can you either post the SRM file as an image for us to look at, or email it to me and i'll have a look.

do you know Dirk?

cheers
ric

The way I look at a time trial is that you should be pretty much exhausted by the end. If you have any thing left at the end you could've gone harder. If it is such a short time trial, it might be worth putting out the extra energy at the beginning of the race because you're losing so much time. I don't doubt that the relationship between power and speed is cubic, but when the even is so short you need to get up to speed as quickly as possible. Don't fall into the trap of only believing the numbers and completely relying on advice people have given you. Everyone one is different so the training advice someone gives you may not match perfectly to how you ride. Next time go out and try to put out some more power at the beginning of the ride and see how you feel. Find a course, measure out the distance and see how you feel. The next week, come back and ride steady power or something. Eventually you will find out how you should start a time trial that short.

atomicrc11 said:

The way I look at a time trial is that you should be pretty much exhausted by the end. If you have any thing left at the end you could've gone harder. If it is such a short time trial, it might be worth putting out the extra energy at the beginning of the race because you're losing so much time. I don't doubt that the relationship between power and speed is cubic, but when the even is so short you need to get up to speed as quickly as possible. Don't fall into the trap of only believing the numbers and completely relying on advice people have given you. Everyone one is different so the training advice someone gives you may not match perfectly to how you ride. Next time go out and try to put out some more power at the beginning of the ride and see how you feel. Find a course, measure out the distance and see how you feel. The next week, come back and ride steady power or something. Eventually you will find out how you should start a time trial that short.

you actually need to carefully pace anything that lasts longer than ~ 60-secs in duration.

trying to do something such as pacing trials out on an open road, would be very difficult due to changes in environmental conditions. you'd need to do many trials all at once (so that environmental conditions were the same) and then you're faced with huge issues of fatigue.

ric

ric_stern/RST said:

Bridge,

can you either post the SRM file as an image for us to look at, or email it to me and i'll have a look.

do you know Dirk?

cheers
ric

Ric,
Many thanks. I do know Dirk and ride with him sometimes. I wil dig out the record and send it to you,
John

[email hidden said:

"]Ric,
Many thanks. I do know Dirk and ride with him sometimes. I wil dig out the record and send it to you,
John

hi john,
yes send us the file, and any stats about yourself (if you want to). i'm sure Dirk will let you know, that i know what i'm talking about!!

cheers
ric

ric_stern/RST said:

hi john,
yes send us the file, and any stats about yourself (if you want to). i'm sure Dirk will let you know, that i know what i'm talking about!!

cheers
ric

Hi Ric,
I follow a lot of your writing and fully understand that you
know your stuff. As a researcher (UofU) in Biophysics and Physiology
I have a particular appreciation for what you write. I hope to send the
records and discuss things with you early next week,
All the best,
John (a fellow Brit!)

atomicrc11 said:

The way I look at a time trial is that you should be pretty much exhausted by the end. If you have any thing left at the end you could've gone harder. If it is such a short time trial, it might be worth putting out the extra energy at the beginning of the race because you're losing so much time. I don't doubt that the relationship between power and speed is cubic, but when the even is so short you need to get up to speed as quickly as possible. Don't fall into the trap of only believing the numbers and completely relying on advice people have given you. Everyone one is different so the training advice someone gives you may not match perfectly to how you ride. Next time go out and try to put out some more power at the beginning of the ride and see how you feel. Find a course, measure out the distance and see how you feel. The next week, come back and ride steady power or something. Eventually you will find out how you should start a time trial that short.

Atomicrcl11
Many thanks for your suggestion, I will go and give it a serious try,
John

[email hidden said:

"]Hi Ric,
I follow a lot of your writing and fully understand that you
know your stuff. As a researcher (UofU) in Biophysics and Physiology
I have a particular appreciation for what you write. I hope to send the
records and discuss things with you early next week,
All the best,
John (a fellow Brit!)

cheers, look forward to getting it and having a butchers

ric

ric_stern/RST said:

cheers, look forward to getting it and having a butchers

ric

TT is not really about constant power. I have seen many try to get up to pace straight from the gun only to burn out before halfway leaving them effectively limping home. The fastest TTers start out quite gently (even in short events) to avoid creating too much lactate too early. It is much faster to produce the lactate towards the end rather than clag the legs at the start and spend half the distance trying to recover or overcome it.
The fastest TT I have ever done was the day after the longest ride I have ever done and I took it easy at the start. I came home much faster and still felt good at the end, but it was fast. It's not necessarily a matter of shagging yourself but of attaining the highest possible average speed.

tafi said:

TT is not really about constant power. I have seen many try to get up to pace straight from the gun only to burn out before halfway leaving them effectively limping home.

even paced power efforts on a flat course are the best way to go. or starting just under estimated average power for the first couple of minutes. that's not the same as even paced velocity though.

if you start out at your average TT power or just below it, the first few minutes would in general feel quite easy.

ric

ric_stern/RST said:

even paced power efforts on a flat course are the best way to go. or starting just under estimated average power for the first couple of minutes. that's not the same as even paced velocity though.

if you start out at your average TT power or just below it, the first few minutes would in general feel quite easy.

ric

I've done exactly 1 TT, with another coming up this weekend that I'm very fired up about. I think I rode the first one perfectly, given my limited abilities. I went just under as hard as I could off the start, knowing that a hard start would gain a few seconds but cost me minutes until I could recover from it. Using a bigger burst of energy up front is a very bad exchange. Better to start reasonably, get up to cruising speed, and then gently nudge up and down over "the line" making sure you are on the edge.

Now that I have a power meter (and I'm going to forego the sexy aero wheels I have and use my heavy non-aero Powertap's wheels) I know that high efforts are expensive! When I am doing intervals at say 240w, a rise in the road that tricks me into 10-20 secs of 300w makes that 240w a heck of a lot harder for a long time after that. I'm sure the same applies to a TT effort, only with much greater cost since your "edge" drops appreciably if you've just blown extra watts for awhile.

[email hidden said:

"]Malcolm Firth has pointed out that, as a consequence of the relationship between power and speed ( which is approximately cubic) it is ideal to time trial at constant power. I have significantly improved my times using this suggestion. I monitor my power on an SRM. However on short time trials (in Salt Lake City we have one by the lake which is 6.8 miles long) my results have not been that good. I can sustain about 311 Watts for 20 mins (on a good day). I weigh 185 lb. When I maintain constant power it takes a considerable time to reach stable velocity presumably due in part due to my large mass.At the turn around I have another slow acceleration. Since a slow acceleration occupies a relatively large proportion of a short trial would it be better to go, for example, for a minute at a power significantly above 311 Watts and then sustain 311 Watts? The time trial usually takes me close to 16 mins and I would like to take 30 secs to a minute off this. In short can an initial burst of effort to get up to speed quickly compensate for the inevitably reduced sustainable power.

power vs speed is roughly cubic at constant speed, if you are accelerating, that changes things...

My gut (I am an engineer, not a trainer) says to go a little harder until you hit a speed that coresponds to 311 watts on a flat, then maintain power...

tamman2000 said:

power vs speed is roughly cubic at constant speed, if you are accelerating, that changes things...

My gut (I am an engineer, not a trainer) says to go a little harder until you hit a speed that coresponds to 311 watts on a flat, then maintain power...

But how would you do the ascents? In my opinion you also lose much, if you don' t concentrate on climbs. Still better not push too much as have been mentioned.

Pobre said:

But how would you do the ascents? In my opinion you also lose much, if you don' t concentrate on climbs. Still better not push too much as have been mentioned.

I guess I may have assumed some data that wasn't stated...

I thought the course was flat for some reason...

tamman2000 said:

I guess I may have assumed some data that wasn't stated...

I thought the course was flat for some reason...

and, if the course is hilly or windy you go harder uphill and into the wind, and easier downhill and with a tailwind

ric

This isn't short tt even close on my scale, but I put it here to see and to create some conversation.

TT August 25 2004, 30km

I Used it for to prepare myself to weekend stage race starting on next Saturday, which starts with often crucial 10km tt. I Had a plan to go easy on the start and progress my speed on the way to the finish so that I wouldn' t get too tired and still get good touch with race pace.

Weather was pretty cold (15 Celsius) and there was some kind of headwind before the 15km turn, maybe 3m/s. First 15km went easily without much of an effort but the next ~11-12km I felt slobby floating in tailwind. Last 3km or so I tried to come with full gas, but I don' t feel that I succeeded very well. I didn' t get the heartrate as up as I usually do and average power was a bit of disappointment compared my earlier readings. I Don' t know if the readings are very accurate though.

My Anaerobic treshold was in February this year 178 b/min and 364 in watts. So in my opinion I should get the average heartrate and power many levels higher even though the distance was 30km / ~42min and I usually do even for couple of hours in road events.

Nevertheless I'm content with the excersice, I believe it was the easiest tt in my life. (And the time was direct consequence of that feeling..) Right now I' m hoping to find some extra edge on the TT next Saturday.