Losing weight to increase performance?

If a very thin (east african) body type isnt in your genetics and lifestyle from birth, its difficult to lose weight and still run competitively. Also, weight is only one of the various factors that influence the time of a race. If it were as simple as just "losing weight", Americans would be running faster, and eddylee would have ran under 4:00 by now. Most runners (even Americans) are already very skinny to being with, and they would be hard pressed to lose an extra 5 pounds. IMO the increased stress on the body would lead to a decrease in energy and have a negative impact on performance.

The equation doesn't take power into play. If you could add strength to the legs without adding mass to the body, you could generate more power with each push-off.

Well, isn't power just energy per unit time? So if it takes the same amount of "work" to run a mile, if you run it in a faster time that requires more power. I think the way I did the calculation was to say, exerting the same effort but with less body mass = faster time.

Either way it's increasing the strength/weight ratio whether you're adding strength with stable weight, or maintaining strength with less weight.

I want to know where the effort is best spent. I mean, if I should focus on leaning out, or just building muscle in the hope that the added strength will more than offset the added weight. I'm not a 4:00 1500m runner, more like 3:50, but I think the idea is still the same.

I think on a thread with jtupper someone said that the easiest way to increase VO2max is to lower body mass.

Thoughts?

no weight, more gain? wrote:

I was thinking about this the other day when watching videos of some Kenyans running. How much extra weight are Americans carrying when they race?

I tried to do a back of the envelope calculation to see how a performance in something like a mile would be affected:

140lb, 4:00 1500m (not eddy lee).

Kinetic Energy = 1/2mv^2 = (0.5)(63.5kg)(6.25m/s)^2 = 1240J

Lose 5lb (2.27kg) to 135lb:

new velocity = sqrt(2*1240J/61.23kg) = 6.36m/s

Which translates to 3:55.8 for 1500m.

When you look around at a 4:00 1500m runner do you see 5lb to lose? Even if it's 1/2 that, 2 seconds can easily be the difference between several places.

I'm aware of the arguments that you will lose muscle mass, but what if you could cut down on upper body muscle mass only? Should we be advocating thinner builds for our distance/mid distance runners? Thoughts?

I see what you're trying to say here but your calculations are way over simplyfied. The human body running is an incredibly complicated mechanism that doesnt lend it self well to being modeled mathematicly. If you are near a college just ask an engineer or a physics prop about the calculation headach. I do comletely agree that being the ideal weight is a huge part of optimal running, I would be very surprised if 5 lbs really traslated to 4.2 sec PRs in the 1500. People fluctuate by as much as 10 pounds or more on a regular basis just due to hydration. Like I said though weight is incredibly important to running fast. The only issue is that you have to be careful with malnutrition trying to lose weight. This comes up a lot with girls becasue they lose some weight and then run faster so they lose more weight and at a certain point they start getting slow due to lack of proper nutrition and losing to much muscle mass. On the other side of the coin Alan Webb has been slow for 2 years i think due to 15 extra pounds.