"There's only one hard and fast rule in running: sometimes you have to run one hard and fast."

Tuesday, March 11, 2014

The most dangerous bad idea in running

From a comment in my last post, I feel I have to address this once again.

Any coach who says "Lose weight and you'll run faster" should be shunned. They should be banned from the sport. It is not only wrongheaded, it's evil. That idea has killed people.

Fallacy 1: But the elite marathoners are all so skinny - it must be right

The three women and three men who made the US Olympic marathon team in 2012 were
Desiree Davila 5'2" 100 pounds
Shalane Flanagan 5'5" 113 lbs.
Kara Goucher 5'7" 120 lbs.
Ryan Hall 5'10 130 lbs.
Meb Keflezighi 5'7" 127 lbs.
Abdi Abdirahman 5'11" 130 lbs.

They're all quite thin. Would they be faster if they weighed less? No. And neither would you. The type and amount of training that elite marathoners do results in the low weights; it's a by-product and not a goal. 5000 meter runners weigh more than marathoners, but are no less fit. Losing weight in itself has no effect on running performance!

Once again, to be clear: Losing weight doesn't improve performance, but improved performance may result in lost weight. Your body adapts to training and one adaptation, to become more efficient, may be to lose weight. Intentionally trying to lose weight to run faster is completely backward. It doesn't work. It has never worked. There is not one single case where someone has done nothing but lose weight and then become faster.

Fallacy 2: But VO2max is based on weight

VO2max, one predictor of running performance, is measured in milliliters of oxygen consumed per minute per kilogram of body mass. Mathematically, at the same amount of oxygen consumed per minute, the less you weigh, the higher (better) your VO2max will be. Besides being but one predictor, and a questionable one at any distance far from 5000 meters, VO2max's dependence upon body mass is complicated. Losing weight doesn't improve VO2max in a predictable manner; the linear relationship predicted only holds over a very small range and that range becomes vanishingly small in some athletes.

Fallacy 3: But I ran faster when I weighed less

My fastest marathon happened when I weighed 30 pounds less than I do now. If I lost that 30 pounds now, I would not be able to function; I doubt I could even get out of bed without assistance. My weight has gone up and down and my performances varied with that weight - for a while. Even when that happened, however, my weight went up AFTER my performances started to slip and my weight would go down AFTER my race times improved for a brief time. Losing weight didn't make me faster; getting faster caused me to lose weight.


Olga King said...

Man, you know, you really just grab a sentence and run with it. "Loose fat", and "to a certain point" (and I ma talking about normal American people too, not elite or semi-elite runners). Don't be a stickler to a letter, no fun. Oh, may be, just shoot me:)
p.s. I ran my best year at my highest of 140, but at the end of that very year dropped 10 lbs and ran better (for one race). After all, it WAS training, but not carrying the flab up the mountains helps.

Anonymous said...

Maybe losing weight isn't the best way to run faster, but to say you won't run faster if you lose weight would be to ignore the laws of physics.

Do this easy experiment. Wear a heart rate monitor and go for a run. Maintain a heart rate of pretty much exactly 140 while running. Record your average pace over half an hour. Now repeat, but while wearing a 15-pound backpack on the run. See if your average pace slowed...

That doesn't mean that losing weight is always the answer to how to get faster, but is *a* answer.


Anonymous said...

The dude who ran 555 miles at ATY and was a top 10 finisher at the world 24 hour championships went from a front of the middle of the pack runner to elite status after he went on a crash diet to become skinny. After he lost the weight, he was able to ramp up his training.


stillwaterrunner said...

All things being equal, I disagree Steve. It will take less energy to move your body if you weigh less. Add hills, and I would think weight is one of the most important factors. Cyclists certainly think so.

SteveQ said...

Some good and interesting points (sorry, Olga, no disrespect intended, really - I really HAVE been a jerk lately, haven't I?) Heart rate is a function of work, which is why it goes up when running uphill, so my argument really only applies to track races, which is where my mind was at the time - no one ever tells trail racers to lose weight. Adding a weighted pack will increase heart rate, as would the equivalent amount of fat, but not all weight is dead weight and, upon training with the added weight regularly, the body adapts and the heart rate goes back down again (though probably not completely).

As for hills and weight, have you noticed that the winners of hilly races are muscular and the gangly guys like me struggle?

Olga King said...

Yes, you have reminded me my ex lately, I am right and everybody else is an a$$.

You said it, guys on the uphill are muscular. I am still talking about loosing fat, a.k.a. dead weight.

Musing (NO science behind from me here, I just don't dig deep enough): if HR is a function of work, as you go faster, HR is faster, and physics laws would imply a bigger mass takes more work to accelerate/propel forward?

And again, please realize that no matter track, road or trail, I am not recommending to go anorexic. I am talking about healthy body and lean muscle.

Anonymous said...

"There is not one single case where someone has done nothing but lose weight and then become faster."

There are plenty of cases, myself included. Every year I run a 10k "fun run." The first time I did it I was 233 pounds and did 1:10 off zero training. I went on a diet. I lost 43 pounds simply by quitting beer and eating better.

At 190 pounds I ran the fun run again (no training this time either) and I ran it in 52 minutes.

It's simple physics.