avge power lower on hilly courses

17-04.-2005, 08:39 AM	#1
rbaral Registered User Join Date: Apr 2005 Posts: 8	avge power lower on hilly courses I have been using my power monitor for approximately a year and have recently returned to racing (pedominantly time trials). I have noticed that my average power over flat courses (maybe with eg 1% grades) is higher than hilly courses. I can maintain 270W for 20km on a 3.8km circuit with a 1.2km elevation of 1% but only ~220W for 20km on a 5km circuit (that is mostly the same as the 3.8km circuit but with a diversion so there's a 400m climb of 4% and another 150m climb of 4% as well as the 1.2km of 1%). I'm assuming the difference in average power is due to the power lost on the downhills. I can divide the 5km course into 2.5km 'uphill' (the 2x 4% grades, the 1% grade and a flattish (slightly up) bit) where I consistently average 270W (though up to ~300-320W on the 4% grade and ~170W for the downhill and flat section (mostly flat since the downs are steeper).....any comments on my logic here? These are training circuits but I've noticed the same discrepancy in hilly vs flat races. I'm hoping for some advice on how to ride hills within time trials most efficiently.

17-04.-2005, 11:37 PM	#2
velomanct Registered User Join Date: Dec 2003 Location: Connecticut Posts: 951	Re: avge power lower on hilly courses you are right on. with the hilly course you spend a lot more time at low wattage or even coasting down the hills. on a flatter road you able to apply a more steady and therefore higher average power. just remember that the highest average power is not always the fastest on a hilly course, for the reason stated above. in a hilly time trial you need to push the uphills hard and stay below threshold to recover on the downhills. __________________ "friendship, family, religion. These are the three demons you must slay if you wish to succeed in business!" -Mr. Burns The faster you go, the fewer passing cars

18-04.-2005, 10:22 AM

Smartt/RST

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Location: Oakland, California

Posts: 266

Re: avge power lower on hilly courses

Quote:

Originally Posted by velomanct

in a hilly time trial you need to push the uphills hard and stay below threshold to recover on the downhills.

Yep...there is more time to be gained by pushing it on the uphill than there is to be lost by recovering on the downhill.

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Smartty

18-04.-2005, 01:45 PM

rbaral

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Re: avge power lower on hilly courses

Thanks for the responses.

Quote:

Originally Posted by Smartt/RST

Yep...there is more time to be gained by pushing it on the uphill than there is to be lost by recovering on the downhill.

How hard should you push the uphills?....can it be quantified by eg CP12 for a 4minute hill? or no greater than 15% above CP60 for an hour time-trial?....or even as hard as you can go but staying below HR anaerobic threshold?

18-04.-2005, 11:31 PM

acoggan

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Posts: 2,592

Re: avge power lower on hilly courses

Quote:

Originally Posted by rbaral

I don't think it really can be quantified, at least not "on the fly" and with the tools that are presently available. OTOH, our brains/sense of perceived effort are apparently quite adept at figuring this out intuitively...see Kraig Willet's article on "supercomputers" on the www.biketechreview.com website.

19-04.-2005, 08:55 AM

rbaral

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Join Date: Apr 2005

Posts: 8

Re: avge power lower on hilly courses

Quote:

Originally Posted by acoggan

OTOH, our brains/sense of perceived effort are apparently quite adept at figuring this out intuitively.

...so we don't actually NEED power meters??? :-)
[don't tell my wife]

Thanks for the responses and links....some interesting reading.

19-04.-2005, 09:57 AM

Woofer

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Join Date: Jan 2005

Location: Northern California

Posts: 594

Re: avge power lower on hilly courses

Quote:

Originally Posted by rbaral

...so we don't actually NEED power meters??? :-)
[don't tell my wife]

Thanks for the responses and links....some interesting reading.

No one needs a power meter. But if you have one the things you can do are fun.

If the climbs are long enough, the meter would be useful for making sure one is doing the max effort one is capable of doing and not slacking or going overboard towards making oneself blow up. Post race analysis lets you figure out how close to optimum your pacing was and let's you compare different races or last year's event versus this years, etc.

19-04.-2005, 03:12 PM

rbaral

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Join Date: Apr 2005

Posts: 8

Re: avge power lower on hilly courses

Quote:

Originally Posted by Woofer

I love my power meter, I was being flippant.....I guess my question was "what is going overboard?" for which there seems not to be a definitive answer.

I was interested in the power pacing concept on the biketech review site and would be interested to try to calculate appropriate power at various points of the following:

the 43km at Calga:

http://www.atta.asn.au/maps/calga.html

and the duathlon Worlds bike course:

http://www.worldduathlon2005.com/inside-worldchamps-course.html

I posted the same question on the bike tech review forum.

20-04.-2005, 07:29 AM

bridge@uofu.net

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Join Date: Aug 2004

Location: Salt Lake City, Utah

Posts: 24

Re: avge power lower on hilly courses

Quote:

Originally Posted by rbaral

I have been using my power monitor for approximately a year and have recently returned to racing (pedominantly time trials).

I have noticed that my average power over flat courses (maybe with eg 1% grades) is higher than hilly courses.

I can maintain 270W for 20km on a 3.8km circuit with a 1.2km elevation of 1% but only ~220W for 20km on a 5km circuit (that is mostly the same as the 3.8km circuit but with a diversion so there's a 400m climb of 4% and another 150m climb of 4% as well as the 1.2km of 1%).

I'm assuming the difference in average power is due to the power lost on the downhills. I can divide the 5km course into 2.5km 'uphill' (the 2x 4% grades, the 1% grade and a flattish (slightly up) bit) where I consistently average 270W (though up to ~300-320W on the 4% grade and ~170W for the downhill and flat section (mostly flat since the downs are steeper).....any comments on my logic here?

These are training circuits but I've noticed the same discrepancy in hilly vs flat races.

I'm hoping for some advice on how to ride hills within time trials most efficiently.

Dear Rbaral,
It is difficult to obtain the same power on the flats and hilly courses. You will usually maintain a higher sustainable power on the flats and on the uphill sections of a hilly course. My own feeling is that on the downhills since you aquire a lot of kinetic energ if you don't spin out you still have the problem of getting force on the pedal early. This is obviously much easier going uphill. I suspect that on the uphill force is applied earlier during the pedal stroke and possibly more uniformly and is therefore more efficient.

I have no good solution to this problem. However I have found that large chain rings (a 56 ) are a help. On the flat iso power is the best way of getting a good time. Since iso power is difficult to achieve on hills the only alternative seems to be to go up a bit harder and hope its enough to compensate for power loss downhill. I have heard at least one coach suggest going up hills at VO2 max power and trying to recover on the downhills. I suspect some compromise and considerable practice will optimise your results. Anyway if you are haveing difficulties so are the competition. If you come up with anything let me know,
bridge@uofu.net

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