test2 wrote:
Jon Orange wrote:Here's a similar graph
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4555089/figure/Fig3/85% VO2 max for a 3 hour race but only 86% for a 2 hour race.
The slower runnre will doubtless have more body fat, perhaps 20% versus 6% for the elite runner at his skinniest.
If both runners have the same absolute VO2 max say 5 liters/minute then the 3 hour runner uses 5 x .85 = 4.25 liters x 180 = 765 liters oxygen
Elite runner uses 5x .86 = 4.3 liters x 120 = 516 liters oxygen
The difference in intensity is minimal. You assumed the fast runner has to have a massively hypertrophic heart. This is the dogma, it goes back to even before you were born. Elite athletes don't have massively hypertrophic hearts.
The slower runner uses more fats and more carbs, as we all do when we run for longer periods.
Jon Orange, I retract my earlier comments about the fractional utilization graph. Rekrunner explained it to me. You are using it in the spirit of Jack Daniels' model. I retain some concers about this approximation but let's let it sit for now.
I have two points to make about your math. You write
Jon Orange wrote:
If both runners have the same absolute VO2 max say 5 liters/minute then the 3 hour runner uses 5 x .85 = 4.25 liters x 180 = 765 liters oxygen
Elite runner uses 5x .86 = 4.3 liters x 120 = 516 liters oxygen
You are multiplying by race duration to get total oxygen use and rightly show that slower, heavier runners use an awful lot of oxygen to finish a race -- perhaps more that an elite runner would use. However, unless we are talking about the fuel stores and the like, I think the physiologically relevant thing is the rate of oxygen use, not the total used.
Jon Orange wrote:
85% VO2 max for a 3 hour race but only 86% for a 2 hour race.
The slower runnre will doubtless have more body fat, perhaps 20% versus 6% for the elite runner at his skinniest.
Let me try to put this in my own words.
In running, it is customary when calculating VdotO2 to divide by bodymass (gives rate of oxygen consumption per kilogram).
This means that an athlete can increase VdotO2_max simply by shedding extra pounds without actually changing their actual (not divided by mass) ability to use oxygen, let's call that abs_VdotO2_max.
I think you are contending that increases in VdotO2 are often interpreted as increases in abs_VdotO2 (i.e. heart hypertrophy, capillarization, mitochondrial growth etc.) when really VdotO2 has only increased because the athlete got leaner and was divided by a smaller bodymass.
Taking the next step, when you say elite runners use less oxygen not more, this is what you mean: training does not increase abs_VdotO2_max, at least not after the first few years. Two questions: 1) is that what you mean? and 2) if so, can you point to a graph of it online? I don't see this particular thing plotted in Daniels Running Formula.
I don't like Vdot. It just confuses everyone and gives the Daniels reader an inferiority complex. The same thing with Daniels' philosophy, he doesn't have a coherent one or a way of empowering the runner with self belief the way that Lydiard did.
I think you are overlooking the efficiency factor. I'm not specifically refering to decrease in body fat, just giving a realistic representation of one of the expected differences between elite and less well trained runners. The efficiency effect happens very well with slightly higher body fat too. A top Kenyan runner will be very swift with 20% body fat and World Class with 10% etc.
test2 wrote:
I think you are contending that increases in VdotO2 are often interpreted as increases in abs_VdotO2 (i.e. heart hypertrophy, capillarization, mitochondrial growth etc.) when really VdotO2 has only increased because the athlete got leaner and was divided by a smaller bodymass.
Yes to the first point. To the second point, it's both lower bodyfat, but mostly better efficiency, otherwise any skinny runner would be World Class.
test2 wrote:
I have two points to make about your math. You write
Jon Orange wrote:If both runners have the same absolute VO2 max say 5 liters/minute then the 3 hour runner uses 5 x .85 = 4.25 liters x 180 = 765 liters oxygen
Elite runner uses 5x .86 = 4.3 liters x 120 = 516 liters oxygen
You are multiplying by race duration to get total oxygen use and rightly show that slower, heavier runners use an awful lot of oxygen to finish a race -- perhaps more that an elite runner would use. However, unless we are talking about the fuel stores and the like, I think the physiologically relevant thing is the rate of oxygen use, not the total used.
No, the physiologically relevant thing is as I have described, and is apparent if you understand the efficiency factor. The difference between the rate of oxygen consumption is amazingly small for the different time duration. This should be obvious from the graph.