I think the first reaction people have is "faster, since you weigh less". But I think the answer is slower, because you would actually be near-floating and contact the ground less.
I got into a fight with people on ask.metafilter when I asked this same question, so I had to let it go. But still I hope someday the Olympics are held on the moon so I can get my answer.
What's not clear is whether you could reach a faster peak speed. I think it would be tough to reach a fast speed since your joints would need to oscillate rapidly in order to push off ground moving as fast. And each time you push off the ground you'd achieve less force, due to the friction thing. To summarize, I think I agree with you that humans will run more slowly in a low-gravity environment.
An interesting parallel question is: under 1.3, 1.5, or 2x gravity, how much more quickly could you run? And what's the optimal gravity for running if it's not 1.0 Earth?
Is "optimal running gravity" the gravity under which you'll run the fastest, or the gravity under which you'll have suffered the least amount of physical damage after running for a fixed distance/time?
http://usbornepublishing.tumblr.com/post/60362087283/it-is-t...
(Scroll to the end specifically for the Olympics.)
It would be interesting if you could achieve a faster speed on the moon running up a flight of stairs than running on a level lunar surface.
Alternatively you could 'angle' the stairs on a level surface (think saw-tooth pattern) and translate that upward energy into forward energy.
Interesting result.
Or if they could touch the ground for longer. We need human mounted wings to provide some downforce :)
Or more realistically an elastic belt strapped to the runner, and running on a track underneath them.
I've modified my running gait to about 186 steps per minute to reduce vertical motion (about 6 cm as measured by the PT at the runner's clinic). I'm still building up the muscles to maintain this gait longer than a minute or two, though.
It would be interesting if a new and improved (or reconstructed Paleolithic) method of running is developed that would enable the average person to reach speeds of 35 MPH (56 KPH) or even faster.
If I could run that fast, I'd get rid of my car and run to work every day. They'd have to have running lanes, maybe even issue speeding tickets to runners who race through a school zone. Road rage would take on a whole new dimension, as well. The economy would be transformed as millions of cars are discarded, gasoline consumption plummets, and people become thinner and healthier.
If you'd asked me how fast an elite sprinter could run today, I would probably have thought of running 100m in a little under 10s, but I don't think I would have connected that mentally with the idea that Usain Bolt runs almost as fast as a car on our 30mph streets, albeit very briefly.
And holy cow, even 25mph is crazy fast, 35? If you tripped and fell at 35-40mph you could seriously injure yourself.
I think I have a good question for the xkcd q&a site: how fast could Usain Bolt run on the moon (ignoring the oxygen problem).
Ah I see someone beat me to the moon problem. Here's another thought, without strong gravity to help return mass to the ground, running is probably much harder.
http://iopscience.iop.org/0143-0807/34/5/1227/article
(That is, yes, you are correct.)
Answering my own question, he took 41 steps when he set the world record.
To be fair, this is quite true at walking speeds as well. Falling is bad. I passed out from dehydration once while standing still; I ruptured my spleen in the fall and almost needed surgery to have it removed (thankfully, it healed while I was under observation).
Correct me if I'm wrong, but if they extrapolated this from one-legged hops, which put all of your weight on a single leg, isn't that more akin to measuring the ground force from jumping than it is to running?
The point is that the limiting factor is not how much force the limb can exert, and that's what was demonstrated by the one-leg hopping.
"Our simple projections indicate that muscle contractile speeds that would allow for maximal or near-maximal forces would permit running speeds of 35 to 40 miles per hour and conceivably faster"
So essentially if human physiology worked differently than it did, we could theoretically run much faster. Not a useless result, but not really anything as exciting as they make it sound.
If you could get all that force into running stance...that's like saying michael jordan has a great vertical. If a runner could apply that same vertical while running top speed, he could leap really far.
it hurts my knees anyway
