The study inspired sports scientists Jonathan Dugas and Ross Tucker to write a series on running economy in their excellent blog The Science of Sport in December.
They make an interesting observation: although the use of oxygen per minute goes up with run speed until the maximum is reached, the use of oxygen per kilometer remains relatively constant.
The less oxygen you need to run a kilometer, the more economical runner you are. Tadese consumes only 150 ml/kg/km, which is amazingly low, considering that the corresponding figure for elite Kenyan and Spanish runners is 192 and 211 respectively.
The economy of running seems to be the key to endurance running performance. VO2 max (maximal capacity for oxygen use) and blood hematocrit (the value that is often measured in doping tests) do not appear to be limiting factors. In the study Tadese's VO2 max was measured as 83 ml/kg/min and his blood hematocrit 44%, which are not exceptional figures for an elite athlete. What's more, he was using only 48 ml/kg/min while running 3:09/km - that is, only 57% of his max VO2.
Well, that's fine, but can running economy be improved, and how? The Science of Sport was able to identify the following factors for the consideration of endurance runners:
- Studies show that running economy improves with high volume slow training. The reason for this includes the increase in mitochondria.
Stiffer joints and muscles are better able to store and release the energy. Less streching and limited flexibility can be a good thing as it means less work is required for stability.
Strength training improves running economy as it improves the function of the neuromuscular system.
So slow, stiff and strong seems to be the new training mantra or motto, at least for those of us who want to optimize their endurance running economy. But whatever you do, just keep running, that's the main thing of course!