Human Running Speeds of 35 to 40 Mph May Be Biologically Possible


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brentaal
ScienceDaily (Jan. 22, 2010) ? Jamaican sprinter Usain Bolt's record-setting performances have unleashed a wave of interest in the ultimate limits to human running speed. A new study published in the Journal of Applied Physiology offers intriguing insights into the biology and perhaps even the future of human running speed.

The newly published evidence identifies the critical variable imposing the biological limit to running speed, and offers an enticing view of how the biological limits might be pushed back beyond the nearly 28 miles per hour speeds achieved by Bolt to speeds of perhaps 35 or even 40 miles per hour.

The new paper, "The biological limits to running speed are imposed from the ground up," was authored by Peter Weyand of Southern Methodist University; Rosalind Sandell and Danille Prime, both formerly of Rice University; and Matthew Bundle of the University of Wyoming.

"The prevailing view that speed is limited by the force with which the limbs can strike the running surface is an eminently reasonable one," said Weyand, associate professor of applied physiology and biomechanics at SMU in Dallas.

"If one considers that elite sprinters can apply peak forces of 800 to 1,000 pounds with a single limb during each sprinting step, it's easy to believe that runners are probably operating at or near the force limits of their muscles and limbs," he said. "However, our new data clearly show that this is not the case. Despite how large the running forces can be, we found that the limbs are capable of applying much greater ground forces than those present during top-speed forward running."

In contrast to a force limit, what the researchers found was that the critical biological limit is imposed by time -- specifically, the very brief periods of time available to apply force to the ground while sprinting. In elite sprinters, foot-ground contact times are less than one-tenth of one second, and peak ground forces occur within less than one-twentieth of one second of the first instant of foot-ground contact.

The researchers took advantage of several experimental tools to arrive at the new conclusions. They used a high-speed treadmill capable of attaining speeds greater than 40 miles per hour and of acquiring precise measurements of the forces applied to the surface with each footfall. They also had subjects' perform at high speeds in different gaits. In addition to completing traditional top-speed forward running tests, subjects hopped on one leg and ran backward to their fastest possible speeds on the treadmill.

The unconventional tests were strategically selected to test the prevailing beliefs about mechanical factors that limit human running speeds -- specifically, the idea that the speed limit is imposed by how forcefully a runner's limbs can strike the ground.

However, the researchers found that the ground forces applied while hopping on one leg at top speed exceeded those applied during top-speed forward running by 30 percent or more, and that the forces generated by the active muscles within the limb were roughly 1.5 to 2 times greater in the one-legged hopping gait.

The time limit conclusion was supported by the agreement of the minimum foot-ground contact times observed during top-speed backward and forward running. Although top backward vs. forward speeds were substantially slower, as expected, the minimum periods of foot-ground contact at top backward and forward speeds were essentially identical.

According to Matthew Bundle, an assistant professor of biomechanics at the University of Wyoming, "The very close agreement in the briefest periods of foot-ground contact at top speed in these two very different gaits points to a biological limit on how quickly the active muscle fibers can generate the forces necessary to get the runner back up off the ground during each step."

The researchers said the new work shows that running speed limits are set by the contractile speed limits of the muscle fibers themselves, with fiber contractile speeds setting the limit on how quickly the runner's limb can apply force to the running surface.

"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," Bundle said.

Science Daily

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bloodrain

i read that entire thing, and it all just seemed like babble. No real useful information.

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peacemf

but not physically possible right ? lol

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Kirkburn

i read that entire thing, and it all just seemed like babble. No real useful information.

It reads like a scientific report. It can't really be all that much simpler without becoming misleading.

In any case, if you do need a summary, it's this: we may have access to more running power than we think. They tried different gaits and found that full speed running wasn't using all the available power.

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Growled

I'll believe someone can run 40 miles per hour when I see it.

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FloatingFatMan

I'll believe someone can run 40 miles per hour when I see it.

But if it IS possible, it's likely to be Bolt who does it! Even he reckons he can go faster, and who but the fastest man alive would know better about his limits?

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carmatic

it sounds like they are measuring only how much force is hitting the ground from the foot, and how quickly the force is applied... not once did they mention anything about how fast the foot is actually moving? as in, the degrees of joint rotation / second ... i would have thought that is the main factor on how fast humans can run...

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Electric Jolt

What's the point? That the future humans are going to be quicker? That's what it sounds like. To me, it would seem they plan on generating genetics for future humans and plan on injecting it into vaginas so babies will be born with with new features.

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+Anarkii

I don't think its physically possible. Our legs just arn't made for it

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petrossa

If it is possible the person doing it he would wish he hadn't after a short time of wearing his cartilage down to nothing due to the enormous stresses generated. Not to speak of his spine. Every disk in it will herniate.

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pasty2k2

If it is possible the person doing it he would wish he hadn't after a short time of wearing his cartilage down to nothing due to the enormous stresses generated. Not to speak of his spine. Every disk in it will herniate.

Herniate... I've a new favourite word!

This is the solution we've been waiting for to one area of the energy crisis - no more cars in future, we run everywhere!

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petrossa

Straight to an early grave.? :whistle:

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FloatingFatMan

If it is possible the person doing it he would wish he hadn't after a short time of wearing his cartilage down to nothing due to the enormous stresses generated. Not to speak of his spine. Every disk in it will herniate.

I'm curious... What makes you come to such a conclusion?

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petrossa

I'm curious... What makes you come to such a conclusion?

Simple logic. In order to generate the necessary momentum to produce such speeds the loadstress in all articulations increases exponentially. The increased momentum will transfer to the ground via the legs, the back takes a increased weight impact. Since the spine in it's design is not yet fully evolved for proper bipedal motion (it's basically just quadriped spine moving on two legs) it'll suffer the loads badly.

As increased wear and tear speed up the celldivision your reserves of telomeres run out quickly resulted in speeded degeneration.

In other words: you can run your car at full speed all the time, but the changes you'll end up in the repairshop are higher than if you just keep it at it's cruising speed.

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FloatingFatMan

As far as the human body is concerned, "simple logic" is usually not sufficient. Sure, for athlete's, injuries to joints and ligament are common when they are too long at the high end of their capability; but that doesn't happen to ALL athlete's. The human body is a remarkable machine, and it continues to evolve. Just take Usain Bolt as an example. 10 years ago, no one would have thought it possible for a human to achieve the speeds he's capable of. 10 years from now, he might be seen as an average runner, who knows.

Right now, this theory of there's is nothing but that, a theory. They have seemingly shown that the previously thought of speed limit being caused by the level of impact with the ground and the duration of that impact is incorrect, and instead its determined by the "twitch" response time of the muscles involved. That doesn't mean a practical answer exists, or ever WILL exist, to speeding humans up. Merely that it's theoretically possible to go faster.

Maybe one day we will, maybe not. I suspect though, that if we DO, it's at the tail end of some further evolutionary steps which will no doubt take care of the incumbent bodily stresses.

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metallithrax

But 35mph would be about 6.5 seconds for 100m.:blink:

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Black Flash

It'll probably be someone with west-african ancestry if it's ever going to happen.

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petrossa

As far as the human body is concerned, "simple logic" is usually not sufficient.

Yes it suffices largely. It's a very fragile sac of bones and tissue. A particle as small as a virus can destroy it within 48 hours.

Cells have a limited DNA repair facility. After the DNA repair mechanism fails you start to age. The more you make your body divide (in order to heal and reenforce structures/muscles) cells the faster you start to age.

Some people with extraordinary genetic makeup have more DNA repair reserves, but the overwhelmingly biggest part doesn't which is why there's an average age of death with a few exceptions to the higher numbers.

But if you prefer to believe a body is perpetual motion mechanism.........who am i to tell it's just not remotely realistic?? :rofl:

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FloatingFatMan

Sorry mate. You might be widely educated in a broad range of topics (or read Wikipedia a lot), but I'm gonna go with a family history of several generations of doctors and nurses. Not me specifically, but I've been around the medical profession all my life from assorted relatives. ;) The human body is capable of all sorts of incredible things.

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Stokkolm

Simple logic. In order to generate the necessary momentum to produce such speeds the loadstress in all articulations increases exponentially. The increased momentum will transfer to the ground via the legs, the back takes a increased weight impact. Since the spine in it's design is not yet fully evolved for proper bipedal motion (it's basically just quadriped spine moving on two legs) it'll suffer the loads badly.

As increased wear and tear speed up the celldivision your reserves of telomeres run out quickly resulted in speeded degeneration.

In other words: you can run your car at full speed all the time, but the changes you'll end up in the repairshop are higher than if you just keep it at it's cruising speed.

It's funny how the researchers say it's possible, but the "experts" here are saying it's not.

If the common acceptance was that the force required to run at top speed for athletes was already at the limit and they proved it is not, then how can you be so sure that the same is true for the spine. How do you know that the spine can't handle more than you "think" it can?

Telomere: the segment of DNA that occurs at the ends of chromosomes.

How exactly would running affect your DNA? You use a bunch of big words to sound smart, but in reality, what you say makes no sense.

Sprinters don't run at full speed all the time, so your car analogy is worthless as well. You should have compared it to a drag car. That would work, except drag cars need to be built in preparation to run, just like runners train for their meets months in advance. Do drag cars have problems after a race, some do, but the majority are ready to go for the next heat an hour later. Same thing with sprinters.

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petrossa

Sorry mate. You might be widely educated in a broad range of topics (or read Wikipedia a lot), but I'm gonna go with a family history of several generations of doctors and nurses.??Not me specifically, but I've been around the medical profession all my life from assorted relatives. ;)??The human body is capable of all sorts of incredible things.

You go wherever you want, i'll just go with simple statistics of injuries and mortality rates associated with sports. I've had this discussion in my blog already if you want i can show you were to start reading the comments so i don't have to repeat it here but the gist of it is that emergency hospital intake is overrepresented by sports injuries.

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petrossa

It's funny how the researchers say it's possible, but the "experts" here are saying it's not.

If the common acceptance was that the force required to run at top speed for athletes was already at the limit and they proved it is not, then how can you be so sure that the same is true for the spine. How do you know that the spine can't handle more than you "think" it can?

Telomere: the segment of DNA that occurs at the ends of chromosomes.

How exactly would running affect your DNA? You use a bunch of big words to sound smart, but in reality, what you say makes no sense.

Sprinters don't run at full speed all the time, so your car analogy is worthless as well. You should have compared it to a drag car. That would work, except drag cars need to be built in preparation to run, just like runners train for their meets months in advance. Do drag cars have problems after a race, some do, but the majority are ready to go for the next heat an hour later. Same thing with sprinters.

Well i can say it in less smart words if you want:

The repair capacity of the mammal body is limited. DNA damage gets repaired with the aid of pieces of building kit to repair it. It's the bodies way of compensating for the inevitable loss of information when cells divide. This building kit is not that well stocked. The more you call on its resources the less the loss of information gets compensated until when it is empty the cell dies off.?

Nature has no use for your body after you procreated, since you'd be only using resources to the cost of the offspring leading to smaller chances of survival of the species. So bodies are made to last for a limited time. This regulated via the mechanism of DNA repair.?

Consequently, if you live 'faster' you die 'faster' since the allowed count of cell division gets used up in a shorter time frame.

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carmatic

'living faster' doesnt mean dying faster... dont you know that exercise makes you healthy, and health means a long life?

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Kirkburn

<snip>

I think the main issue people have with your argument is that sprinters aren't doing so all the time. Most of the time they're about as active as other people.

They might run a few times a week, but it's not continuous. Certainly athletes have issues with wear and tear, but I don't expect it would suddenly become widely catastrophic once we reach some arbitrary point. 50 years ago you might have thought Bolt-like speeds would have surpassed this point, but evidently he has not.

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boogerjones

Some people think that women will eventually be faster long-distance runners because of their extra fat storage.

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