# "The 33"-Road Bike Racing - Watts vs oxygen consumption

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View Full Version : Watts vs oxygen consumption

procrit
10-28-10, 12:29 PM
After 4 vo2 max tests I got my own watts to oxygen consumption equation that predicts my oxygen usage within 1% percent accuracy. Works all the way from 100 watts to vo2 max (~400 watts for me).

Watts = ( Absolute Vo2 (L/min) - .9579) / .0095

or

Absolute Vo2 (L/min) = .0095*Watts + 0.9579

My best 30' power record this past Spring was 340 watts. That puts me at 4.19 L/min, or around 89% of my vo2 max, 4.7L/min.

Lance's 30 minute, 495 watt record breaking effort up the Galibier in 2003, according to my equation, would have taken 5.66 L/min. That's 90% of his vo2 max, 6.3L/min. His relative vo2 max is 84 L/kg-min. That seems about right according to the net.

Anyone with numbers care to see how close it works for you?

tallmantim
10-28-10, 06:46 PM
Well, top end of VO2Max is 447 from WKO+ (ie, I have done no testing to see if this is right and don't do any intervals aimed at that), so that would put me at 5.2L/min or 56mL/min/kg - which is in line with the figure I got from this site that also has a calculation for O2 consumption:

http://www.hillclimbr.com/sites/climbr/climbr.nsf/category/8059E65357032EEEE925749F007B66EA?OpenDocument

to get a value for VO2 you need to enter your climb as a maximal effort. Here is my effort:

http://www.hillclimbr.com/sites/climbr/climbr.nsf/docid/5FB2AFA57CEDFD79E92577790026B3E5?OpenDocument

which shows a VO2Max of 54mL/min/kg - bang on the money really seeing as I have lost weight since then.

Interestingly that site also calculates your watts for the climb - listing that one as an average of 328W, however the real figure for that one was actually 385W - so I must be blowing a lot of my power on CdA (which I have been working on).

Cheers

procrit
10-29-10, 07:37 AM
Wish I had a 5.2 L/min vo2. 90% of that would put me at a 390 watt FTP, 5.3 w/kg. Gotta love run-of-the-mill aerobic genetics.

tallmantim
10-29-10, 07:56 AM
Wish I had a 5.2 L/min vo2. 90% of that would put me at a 390 watt FTP, 5.3 w/kg. Gotta love run-of-the-mill aerobic genetics.

LOL - and I wish my bones were filled with helium that would get me to 74kg! At a broad 6'4" there's got to be some advantage to being big, and my body will process more O2, but it then needs to carry those large lungs and the rest of my carcass up hill!

;)

Funny that I'm still considerably lower in raw terms than Lance - having 20kg or so on him but him being able to utilise less oxygen. I guess my hemocrit score would have been considerably lower than his in 2003...

:lol:

procrit
10-29-10, 09:14 AM
Check this out though. If you can make 5.2L/min, you SHOULD be able to hit 390-400 watts for an hour by focusing efforts on boosting your FTP. Get down to 80kg and you have a 5w/kg FTP. That's good enough to get results in the cat 1's.

tallmantim
10-29-10, 05:05 PM
Check this out though. If you can make 5.2L/min, you SHOULD be able to hit 390-400 watts for an hour by focusing efforts on boosting your FTP. Get down to 80kg and you have a 5w/kg FTP. That's good enough to get results in the cat 1's.

Yeah, the wattage target is where I am aiming, and am still seeing good improvement. On the weight side however I have a large build (I'm not fat, I'm big boned goddamnit!) - I was 88kg and very lean at 18 years old and have just weighed in at 91.5kg this morning which is on my current goal weight.

The only real way I would get down further would be to lose more muscle mass (getting down to this weight has shown me veins I didn't know I had!) - which if I keep the training up may happen on my upper body but that wouldn't please my wife too much.

;)

She's already well and truly fed up of hearing about glycogen, energy conversion and power increases.