Great find. I don't doubt that prosthetics will allow people to run faster in the future. Feet are good for balance but bad for speed.
Submitted by brainwipe on Mon, 2008-01-14 11:30
Not just feet. Those pesky forward pointing knees are a big problem, too. :)
Submitted by AggroBoy on Mon, 2008-01-14 11:39
Really?
Submitted by baron on Mon, 2008-01-14 11:48
I saw this guy run last year against elite able-bodied athletes. He lost (quite convincingly so), but he was pretty confident that he could improve enough to give them a run for his money.
Biologically, if you want to go fast you want to;
1) Lose toes down to 1
2) Elongate said toe
Horses/gazelles are the best example...one toe, and the toe joint is easily mistaken for a knee its so long (hence the backwards knee). With this guy, if you envision the blade as the "toe", his hip becomes the knee, and now hes driving momentum from the biggest muscle set in the body (quads), rather than the calf with human runners.
That said, I'd let him run. Right now I don't think he can compete enough to win, but he's obviously got the right attitude, and there have been other examples of "disabled" athletes competing against able-bodied ones (classic example being partially-sighted swimmers who used to butcher others in the para-lympics). His prosthetics are not an option for most athletes (unless they are happy to chop their legs off) so its hardly cheating...
Submitted by babychaos on Mon, 2008-01-14 11:58
Animals that need to move quickly tend to evolve out their feet.
Submitted by brainwipe on Mon, 2008-01-14 11:58
I was more curious as to why a backwards knee was better than a normal one for speed.
Submitted by baron on Mon, 2008-01-14 12:02
Pete got there first with a much better answer. In fact, I'd go as far to say that Pete told me this in the first place.
Submitted by brainwipe on Mon, 2008-01-14 12:02
Does the Cheetah's leg and elongation of the foot upwards go along with this?
Submitted by baron on Mon, 2008-01-14 12:09
Yes, it's exactly the same principle. As Pete pointed out, it's not really a knee (except in the sense that people tend to call whatever joint is halfway up the leg a knee,) but most species adapted for speed have very similar leg morphology. There's variation as to whether an elongated toe or foot is used - usually with predators elongating the foot, so as to keep individual toes, which are mounting points for claws.
The Cheetah's real secret isn't it's leg though (well adapted though it is,) it's the fantastically elastic spine which allows it to get it's rear feet significantly in front of it forefeet with each stride before snapping back to a straight(ish) spine and thus propelling itself forwards like a released spring - and this many times a second. If you ever get a chance to see good slow motion footage of one run, do so; it's really spectacular.
For a good demonstration that the same leg morphology works well in bipeds, have a look at a kangaroo in motion.
Submitted by AggroBoy on Mon, 2008-01-14 12:21
If you look at how you run, the forward momentum is generated in main by pushing off with the toe, so the main power joint is actually the ankle, with the main muscle generator being the calf (so a backwards facing joint). The knee is used for lifting and lowering the lower leg, while the quads deal with lifting the body (so up and down force).
So if you want to go faster, you increase the leverage of the "go forward" joint, which faces backwards. So its not so much that the forward pointing knee slows us down, its that the foot is too short and too heavy.
Submitted by babychaos on Mon, 2008-01-14 12:24
Kangaroos are a different stlye of movement. Quite simply they jump up high, then lean forward. Its inefficient at low speeds, but at higher speeds far more effective (as to go faster they just lean forwards more)...up and downy movement comes from the quads, and they have monstrous ones...
Cheetahs are fast, but very, very inefficient...those sprints burn up indecent amounts of energy...
Submitted by babychaos on Mon, 2008-01-14 12:26
Right, get you.
We'll bring over the band saw and springs later...
Submitted by baron on Mon, 2008-01-14 12:27
... I was going to go further into kangaroo locomotion and how it might give us clues as to how speed-enhanced humans might move around, but
a) I'm busy at work, and
b) we're gone quite a way off topic, and I doubt anyone bar those doing the writing is remotely interested, so...
.. I'm going to shut up, even though gait-selection and limb morphology is hugely interesting to me. :)
Comments
Great find. I don't doubt that prosthetics will allow people to run faster in the future. Feet are good for balance but bad for speed.
Not just feet. Those pesky forward pointing knees are a big problem, too. :)
Really?
I saw this guy run last year against elite able-bodied athletes. He lost (quite convincingly so), but he was pretty confident that he could improve enough to give them a run for his money.
Biologically, if you want to go fast you want to;
1) Lose toes down to 1
2) Elongate said toe
Horses/gazelles are the best example...one toe, and the toe joint is easily mistaken for a knee its so long (hence the backwards knee). With this guy, if you envision the blade as the "toe", his hip becomes the knee, and now hes driving momentum from the biggest muscle set in the body (quads), rather than the calf with human runners.
That said, I'd let him run. Right now I don't think he can compete enough to win, but he's obviously got the right attitude, and there have been other examples of "disabled" athletes competing against able-bodied ones (classic example being partially-sighted swimmers who used to butcher others in the para-lympics). His prosthetics are not an option for most athletes (unless they are happy to chop their legs off) so its hardly cheating...
Animals that need to move quickly tend to evolve out their feet.
I was more curious as to why a backwards knee was better than a normal one for speed.
Pete got there first with a much better answer. In fact, I'd go as far to say that Pete told me this in the first place.
Does the Cheetah's leg and elongation of the foot upwards go along with this?
Yes, it's exactly the same principle. As Pete pointed out, it's not really a knee (except in the sense that people tend to call whatever joint is halfway up the leg a knee,) but most species adapted for speed have very similar leg morphology. There's variation as to whether an elongated toe or foot is used - usually with predators elongating the foot, so as to keep individual toes, which are mounting points for claws.
The Cheetah's real secret isn't it's leg though (well adapted though it is,) it's the fantastically elastic spine which allows it to get it's rear feet significantly in front of it forefeet with each stride before snapping back to a straight(ish) spine and thus propelling itself forwards like a released spring - and this many times a second. If you ever get a chance to see good slow motion footage of one run, do so; it's really spectacular.
For a good demonstration that the same leg morphology works well in bipeds, have a look at a kangaroo in motion.
If you look at how you run, the forward momentum is generated in main by pushing off with the toe, so the main power joint is actually the ankle, with the main muscle generator being the calf (so a backwards facing joint). The knee is used for lifting and lowering the lower leg, while the quads deal with lifting the body (so up and down force).
So if you want to go faster, you increase the leverage of the "go forward" joint, which faces backwards. So its not so much that the forward pointing knee slows us down, its that the foot is too short and too heavy.
Kangaroos are a different stlye of movement. Quite simply they jump up high, then lean forward. Its inefficient at low speeds, but at higher speeds far more effective (as to go faster they just lean forwards more)...up and downy movement comes from the quads, and they have monstrous ones...
Cheetahs are fast, but very, very inefficient...those sprints burn up indecent amounts of energy...
Right, get you.
We'll bring over the band saw and springs later...
... I was going to go further into kangaroo locomotion and how it might give us clues as to how speed-enhanced humans might move around, but
a) I'm busy at work, and
b) we're gone quite a way off topic, and I doubt anyone bar those doing the writing is remotely interested, so...
.. I'm going to shut up, even though gait-selection and limb morphology is hugely interesting to me. :)