Running Economy Introduction

06 Dec 2007 Posted by

Zersenay Tadese – the most economical runner in history?

Well, a provocative headline for sure, but that’s pretty much what a SCIENTIFIC study has suggested after measuring the oxygen consumption and running economy of the World Cross Country and Half Marathon champion recently! The study, published just the other day in the British Journal of Sports Medicine, and performed by Carl Foster and Alejandro Lucia, found that Tadese has one of the best (if not THE best) running economies ever measured [cite]10.1136/bjsm.2007.040725[/cite]. That is, he uses LESS oxygen at the measured running speed than any runner reported before him.

I would not question the study for a second (well, not too critically, anyway), as Foster and Lucia are both excellent scientists, with great records in the field. Foster is famous for his modeling of pacing strategy and performance, while Lucia has been one of the leading researchers in cycling performance, doping and the physiology of performance. So some credible names, and a fascinating paper, for sure!

We are always on the lookout for interesting news stories here at The Science of Sport, and we do our best to take sports news and explain the science behind it. But this particular story is both newsworthy and science-worthy at the same time, and we say thanks to George (a self-described devoted reader of the blog) for bringing it to our attention!

Introduction of a new series – running economy

What we would actually like to do before we analyse this paper (and Tadese’s new claim to fame) in tomorrow’s post, is to use this really great story to introduce a new series and discussion around this concept of running economy. I seem to recall that about three months ago, there was a whole spate of articles on running economy – for some reason, it suddenly shot to prominence and a number of widely read newspapers started writing about it as though it was the very latest thing, even though we’ve known about its importance for about 30 years. And even back then, we considered the prospects of some posts about running economy, but they got kind of swept away by the heat of Chicago and the racing in New York. Well, no time like the present to go back there!

Running economy 101 What is the big deal?

To begin with, running economy in humans is probably analogous to cruising-efficiency in a car (not entirely, but we’ll get there!). If you think of a human, we can measure the maximum volume of oxygen that can be used, and this is called the VO2 max or VO2 peak. The problem is, for most running events (certainly above about 5000m), runners don’t use this “maximum” amount – they are sub-maximal. And so therefore, a more important measure becomes the volume of oxygen that is used up when the runner is going at a sub-maximal speed.

So to return to our fuel analogy, it’s saying that the car is cruising along at a speed lower than maximal, and we’re interested in how much fuel it uses per kilometer.

Now, there is plenty of reason to think that running economy is very important. There used to be a perception, which still exists in many circles, that the be-all and end-all of running performance was the VO2 max value. In other words, you’ll still find people who think that the runner who has the highest VO2 max is the guaranteed winner. Many runners who have been tested wear their VO2 max like a badge of honour if it’s high, whereas they hide it away if they think it’s low, such is the importance that has been placed on this measurement.

And of course, it is still crucial that a world class runner have a higher than average maximum ability to use oxygen. So you’d be very hard pressed to find any world-class runner who has a VO2 max lower than about 70 mL/kg/min (this is the unit for VO2 max, by the way – it’s a volume in mL, expressed relative to body weight over time). Your typical moderately fit male, weighing about 80kg, would have a VO2 max of about 50 to 60 mL/kg/min, and a fairly well trained athlete might hit the mid 60′s, with the better ones being higher than this, into the 70′s and 80′s. So there is a “GENERAL” trend for the fitter, more highly trained athlete to have a higher VO2 max (although we would argue that is a consequence and not a cause of performance).

But then there’s a catch Maximum is not the deciding factor

The reality however, is that you don’t always get this nice, uniform increase in performance with an increase in VO2 max – often times, a guy with a VO2 max of “only” 75 ml/min/kg will beat a runner whose VO2 max is “superior” at 85 ml/min/kg. And so clearly, there is more at play than simply the size of your lungs, your heart and the muscles maximum ability to use oxygen.

Intuitively, you recognized that this makes sense – as we pointed out above, because 10000m races are run about 90% of VO2 max, and marathons are run at 80 to 90% of VO2 max, there is room for difference because it’s the runner’s ability to use the oxygen most efficiently that contributes a substantial amount to performance.

So that’s where running economy enters the equation. Whenever you read a book on this subject (be it Lore of Running, or any other text), you always see the concept of running economy introduced in this way – it’s the excuse for the “little guy” (in terms of maximal oxygen use, anyway), beating the big guy!

Considering how important running economy seems to be, it’s apparently been ignored in the literature. Last year, in October, a seriously high-powered gathering of exercise physiologists and scientists gathered in Chicago for a conference on Marathon Medicine and Physiology.

And at that conference, Carl Foster, one of the authors of the Tadese paper, discussed the role of running economy in performance. He suggested that the science has “ignored running economy” to date, despite knowing about it for 30 years, and as a result, relatively little is known about the topic.

It therefore seems like a nice, juicy and interesting topic to tackle in a series, and so what we’ll do over the next couple of weeks is take a look at running economy. We’ll begin with an analysis of the study on Zersenay Tadese, which began this post, then we move onto the importance of running economy, the factors determining running economy, and methods that you can use to improve your running economy, and hopefully performance.

So join us over the next few weeks as we get into what could be a very interesting discussion!

Ross

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