How much faster are lighter shoes?

The thinner the midsole, the less the shoe will weigh. (assuming we are comparing top quality shoes, which use EVA and technologies which are particular to each shoe company.)

Anyway, the thinner the midsole, the more one will be able to "feel" the ground with his/her foot, thus landing lighter on his/her feet.

The less a shoe weighs, the lighter you land and less impact on your body.

I can't point you towards any research on the subject. I've always heard that for every ounce lighter, you gain about 1 second per mile.

Couldn't you make the simple F=ma argument? It requires more force (and therefore energy over a period of time) to move a more massive shoe the thousands of steps it requires to run a race. Google it if you want actual speed study.

Your friend may require more support and may be more comfortable in a heavy shoe so these factors may outweigh the benefits of a light shoe. If I ran a marathon in a "minimalist" shoe I would be in so much pain from the heal impact that I would run like crap regardless of the weight, not to mention I would get injured. (I know this from experience.)

1sec/1mile wrote:

I can't point you towards any research on the subject. I've always heard that for every ounce lighter, you gain about 1 second per mile.

Is the for one shoe or for a pair? :)

1sec/1mile wrote:

I can't point you towards any research on the subject. I've always heard that for every ounce lighter, you gain about 1 second per mile.

You're confused.

You lose a second per pound lost.

bowerman said for every oz heavier a shoe, you lift 55 more POUNDS over the course of a mile

billbows wrote:

bowerman said for every oz heavier a shoe, you lift 55 more POUNDS over the course of a mile

How do I convert 55 pounds per mile to seconds per mile? ;)

55 pounds is about a half step or so. Over 26 miles that'd be 13 steps, or 10 seconds I guess.

Hmm, seems like there is not much known how much a light shoe is really worth when it all comes down to....?

I know I remember Noakes saying something about this subject in Lore of Running, and knowing Noakes, he probably had some science to back it up. That book's freakin' ginormous though, and I'm way too lazy to go try to look it up, so I can't give you any more than that...

I don't know the exact figures, but I do know that when I wear the Brooks Beast vs race flats intervals seem to slow down by at least 5 seconds a mile, probably more.

A couple of decades ago I raced a local low key approximately 3 mile race once a week for 8 weeks while doing base training in the winter.

I ran each race as fast as possible and usually wore 7 to 8 ounce racing shoes. The pace was usually around 5 minutes to 5:20 per mile.

The course was on a smooth asphalt path and so the 5th week I ran the race barefoot. My time for that week was more than 10 seconds per mile faster than the fastest of the other 7 races.

Somewhere on this site (http://www.biomechanica.com/index0.html) I read that every extra 100 grams (3.5 ounces) increases the energy cost of running by 1%. The question I have is do leg muscles have to compensate for reduced shock absorption of shoes with paper thin soles?

Running shoes are not simply dumbbells attached to your feet. If they were, we would all run barefoot or with a thin layer of silk on our feet. Today, with most all shoes in the range of 7 to 12 ounces, you can't simply say that running in a lighter shoe makes you faster. Years ago, when the choice was between a 12 ounce running shoe and a 18 ounce basketball shoe, it was easy to say a lighter running shoe was better. A heavier shoe can provide benefits (cushioning, stability, traction, protection) that a lighter shoe does not.

I ran a 2:02 800 with Asics spikes, but when I bought some victories i immediately dropped 3 seconds to 1:59

You are already stable running barefoot, and get plenty of traction barefoot on most surfaces.

Cushioning slows you down.

The only benefit of a running shoe is protection.

The only benefit of a running shoe is protection???

Up here in the north when it gets to -35 c my shoes seem to keep me a bit warmer.

I think (and I might me wrong) that the big benefit to lighter shoes is that the hamstrings have to do less work lifting your foot/lower leg and can rely more on elastic recoil for leg follow-through. Basically, your turnover will be easier to maintain at a high rate with light shoes. It has to do with levers. A weight at the end of a lever (your foot) affects the entire system more than a weight anywhere else - like being at the end of a seesaw makes you seem heavier than at anywhere else on the seesaw. Your hamstrings, which provide the torque to move your lower leg through the backswing portion of your stride, have to do a lot more work if there is a big ol' heavy shoe on the end of your foot. The muscles cannot contract as rapidly against this increased force, so you won't be able to bring your foot in toward your body after push-off as easily or as quickly as you could have with a lighter shoe.

Additionally, with a lighter shoe, you have to compress less foam while pushing off. It is like the difference between running on asphalt and soft grass: when you run on grass, you get much less energy return for the amount of force you put into the ground because you have to spend a lot of energy just compressing the surface so that you have something solid to push off of.

I hope this all makes sense. If it doesn't, I accept full responsibility for being an idiot.

naia champ wrote:

Somewhere on this site (http://www.biomechanica.com/index0.html) I read that every extra 100 grams (3.5 ounces) increases the energy cost of running by 1%. The question I have is do leg muscles have to compensate for reduced shock absorption of shoes with paper thin soles?

Interesting....

In light of my post above, I would have to say that yes, your leg muscles would have to compensate, but this time the burden of compensation would fall mostly upon your quads. If you wear heavy, cushioned shoes, your quads get a break while your hamstrings have to do a whole lot more work lifting the sucker off the ground. It is the opposite for lighter shoes.

I have a feeling there is some trade-off value where the effort for both types of energy expenditure are minimized relative to one another. For example, a shoe just heavy enough to provide shock absorption while not drastically increasing the weight at the end of your lower-leg-lever. I think this also depends on the mathematical relationship between each type of force and how we compensate for it. If one relationship is exponential while the other is linear, we should try to reduce the exponential one at the cost of the linear one because we'll get the most benefit that way.

Your running speed and running form may even play a role in how much extra shoe-weight affects you. If you are running very quickly and efficiently, you are putting more of your force into forward motion and therefore do not need to rely on your quads absorb as much impact force. You can therefor afford to run in a lighter shoe.

Basically, I think that at some point, lighter shoes are not better. Where that point is, though, is up for debate.