Hope y'all are doing well. Thinking about all of you as the school schedule has been massively disrupted. Stay safe, wash your hands!

FROM THE MOMENT I UNDERSTOOD THE WEAKNESS OF MY FLESH, IT DISGUSTED ME.

Great informative video, as a visual learner, the animation really helped me learn new things about prosthetics and runners. Stay safe during the pandemic!

I love the way you guys say "100m dash". Each video looks better than the one before. And loads of info in this one! Animations so good. Ah simpler times, when Pistorius was...mostly out of the news

Good video! Oscar legs are not only built to run, they are built to ran on a specific surface with a specific distance. Lower legs are lighter, do not get tired and built for a specific purpose. Everyone else’s legs are multiple-purpose. Walking, climbing, swimming crawling, jogging, running and sprinting. You have to train natural legs to become more specific but, they still have the multipurpose baggage. It’s definitely more of an advantage. And as the author pointed out , the sample size was much too small. Even though there may not have been a detected metabolic effect there still seemed to be a mechanical advantage. As far as stiffness decreasing with speed with prosthetics, each blade is adjusted to match the athletes top speed. Anyway, that what I think

What a fantastic video. I really appreciate you put all research together so that the viewers can easily understand! I love it.

Excellent video! I love finding informative, well-researched content that I can use for homeschooling. Your channel is most appreciated.

I'm writing a research paper, and your sources and information really helped me condense my thoughts and guide my paper. Thank you!

Great video Mr. Kelly! It’s nice to see how much your channel has grown since you started. (This is Ethan Felipe btw)

Hey Corporis. Can you update your sorces in the discription? you listed the same studie for german study 2 and 2009 Rice U Study. Thanks :)

Great job with the video overall. I Was especially impressed with your ability to present the biomechanics in an accessable way. The point about the amputee's hips struck me as particuarly interesting. The one point that you did not bring up was how the 2013 study noted how this phenomenon is actually inhibiting the amputee. As you pointed out, the 2013 study claimed that the change in vertical hip stiffness must be decreasing as running speeds increased for the amputees (They found that total leg stiffness decreased while stiffness of the prostetic remaind constant). The stated distinction that the amputee's hip had "shock-absorbing function rather than a spring-like function" was a subtle note about running efficiencies. "Perfect" shock absorbers are 100% inelastic, that is they do not return energy, so "shock absorbtion" in this context is counterproductive to running quickly. The telling line in the study related to this was "Furthermore, these compensatory movements may induce greater inefficiency and a higher injury risk during running as long term consequences ". I don't think you misrepresented any of this, I just thought you might be interested in this additional detail of how prosthetics do not provide a competitive advantage. Keep up the good work, Louis

Very well researched video, thanks for the sources in the description too

Great video. Very informative.

Ahha, eyy its ya Boi, Octane

Great video man

What about above knee amputees in the future how will we be able to tell their robotic knee doesn't give more energy output than input

I meant to comment earlier, but I really loved this video. This is something I had been wondering for a little while now. Every question that came up during the video was answered later in the video. I really do feel well-informed on the topic after watching. I was thinking about the future, specifically if battery technology and brain-machine interfaces ever evolves to the point where true robotic limbs become possible. I can see the cutoff being more clearly based: human powered limbs are ok, externally powered not. Think about how crazy it would be watching a "foot" race with externally-powered mech limbs that the "runner" is more riding in than wearing. It'd be like part foot-race, part NASCAR. I...I think I'd watch that lol.

If blade running gives such a great mechanical advantage, could it become a sport in it's own right? Could this be a light weight, portable device that would enable anyone, whether amputated or not, to run further and faster than they otherwise could? Could be fun to just run around town on super efficient blades- run to work, run to the store, just run around the trails.

Not having lactic acid build up in the knees has to be a huge advantage, especially when doing the 400 meter. Also the cheetah legs weigh less than normal legs.

Great work

Hmmm...getting the athletic body to change its mind is not going to happen. Even with overwhelming evidence of non advantages. Because... if they admitted they are wrong, it would constitute a huge loss of face. My best guess is that they also think allowing amputees to compete would affect their bottom line.

I don't understand, can someone please explain , how 400 m gap is smaller than 100 m gap Or I am misunderstanding the gap concept .. Please explain

great work

Great piece! First I've watched on KZfaq. Given your education it must have been a mind bender trying fit these study's into a 12 min piece and not even be able to touch on the anatomy of being disable. How can it be allowed to have such a world changing decision based of people with remedial education in prosthetic's. I look forward to reading these study's, but might puke how objective the two German study's were and Plos flat out wrong in so many ways. I had to watch the last 2 minutes over and over again to make sure I wasn't misunderstanding Plos conclusions. One being that top speed is only about the shape... wow that is profoundly incorrect. I promise length and stiffness are EXTREMELY influential in the athletes ability to generate the forces needed to obtain the optimal speed, or detrimental to reaching desired speed equally. That's saying running in a spongy running shoe is the same as running in a stiff sprinting shoe. I refrain from saying TOP SPEED as they did. Top Speed mean nothing in a foot race of elite athletes who are going to be really close to each others maximum speeds, but vastly different how quickly they get there if needed like a 100m or 200m, maintain max velocity for the longest distance then who decelerates the least at the end wins, bolt was an anomaly for the record, but watch his career in on video, he has the tools that people say are not an advantage, like being tall but he was losing until he trained to maximize running with that body type. Seeing Blakes foot was interesting because I just saw links of people saying how advanced it was and so on... I literally sat at coffee table with the lead engineer in 1997 and influenced that unique shape while everyone was on a Cheetah. The DNA of that shape has not changed a bit, but our training has, rehab has, access has grassroots programs have. Did you know they live at the Olympic Training Center. They have housing, facilities, cooks, medical, chiro, rehab vudu magic everything full time. Blake isn't the first double amputee and definable wasn't the most gifted or disciplined for a while, he became a pro athlete and it was his life style. I lost every race from 1997until 2000 prelims when I had what we call the click factor. It happened because my foot slightly de laminated 2 minutes before prelims then "runners to your marks". I slowed down and ran on form.. I broke the WR, I got out of my own way I let my training take over, didn't force it. Next day new one was attached and ran the same way winning the 100m T44 gold in 2000 Sydney, then I destroyed the record again in the finals. I never lost that race in 9 years until my Achilles ruptured leading the finals in Beijing with 40 meters left, and Oscar Pistorious behind me again. That was not the foot magically giving me an advantage, it was my body getting back more and more of what my anatomy lost. also, Spring lite was bought after the 2000 games so I ran on the cheetah with .01 incremental progressions for years. Seeing these study's so far is sad, this is great information for medical devices to help disabled people but not relevant to the advantage discussion. The host saying their study group is small is due to a lack of elite athletes.. I never heard of any of these study's. I did my own in Iceland. Tosh in salt lake and chula vista. In track and field on these devices there is not a person that was the highest ranked elite athlete who competed with these blades across multiple disciplines and owning the world records too. 100-200-Long Jump and High Jump, 400 m relays. In the High Jump I hopped to the bar. I was the first to ever run sub 11 seconds. I'm not trying to be hyping my successes, but just validating myself when I say that they are wrong and of course one companies design is better than the others... So are shoes, golf clubs, bikes so on. They are not bionic! What in the hell is the IOC scared of? All of a sudden there will be a bunch of athletes come out of nowhere and win because of their fake legs? On ESPN Plus the German scientist said if we allow amputees in our sport there will be a paradox of athletes amputating their limbs to break world records..... He led the damn study so that should upset people for not being provided both ends of the story and from a person of influence being childish about a serious situation of limiting the capabilities of human perseverance,and limitless ability to adapt, evolve and concur. Lastly, and sorry I went on and I'm not spell checking, I'm to tired and saddened. This kept me up all night and morning researching what has been said. They are going into these studies looking for advantages, only advantages. The energy expended by an amputee to make the walk to the track is 5X, to get to the shower is harder, to handle the unnatural forces with underdeveloped limbs in sockets cause constant injuries. This is foolish to say being an amputee is an advantage if an able bodied athlete. Those bladed store energy and the alignment when it's returned is all over the place. watch oscar head on, his for sucks. They put those feet in a jig and that alone lessens the integrity of the results. The feet do not get stiffer or less stiffer when running. the foot can only be setup at one chin angle, and I set mine up to push out of the the blocks, others setup to maintain a good stride length. That matters badly toward having an advantage. Some feet taper at the toe so it is the same stiffness beginning to end but I can see a flaw there. two of those feet are the same thickness pylon to toe. Not all J shapes are equal at all. I helped on both main ones profiled10 years ago and 19 years ago. Blakes foot we had a arch built in. I did that to my foot so it would not flex anywhere but the curve that helped my start, but took away from my finish the same as the arch on a real foot. And all these feet that are the same model are all the same length in the pylon. Bi laterals just mount them higher or lower so lower STIFFENS the foot PLOS, it's a shorter lever then! But every person has an advantage at some part. Some just perfect that while others have better resources to medical.. That's not a level playing field? Make them run bare foot then, shoot guns that are not carbon fiber weighing nothing. Some can't buy that stuff, so it an advantage. But the height of the amputee is without argue a fucking problem. It has been since the beginning. That can be fixed and should be where the effort is. Then the end solution is using the right people of education using race, bone structure, ect. people know anatomy and already do it off DNA so set a threshold of plus or minus. The feet will never give you back more than 100% ( and it is actually 70-80%), but the sound side produces more force that we put into it. It's range of motion and contraction is unreal.. look at the bicep. 450lbs of pressure to curl a 50lbs dumbbell. So many athlete use steroids, epo all this shit and maybe get a few year ban. This situation has put a life time ban on disable athletes moment of injury, birth defect or traumatic injury. It is the Olympics, and it inspiring and it's been given no responsibility to prove why the are discriminating against human rights and able to put it on an athletes shoulder to prove what they don't care to understand. If they wanted the data they wouldn't take down the measuring devices used to study athletes time and stride length at the Olympics but not the Paralympics. And yes, If a dumb ass athlete is willing to store blood and inject it in them, then add epo, testosterone and hgh to win,then they would cut off their damn foot if it was an advantage. Find those Olympic study's we did asking if we took x and knew we would win the gold but die in 5 years would you do it.... Thank you for educating me, I have a lot to learn so keep it up!

Superb vid

I always say that if I ever lost my legs I would want these. I see these as an augmentation

Thankyouuu loved it

When Blake (the man who broke the record for the 400 m dash with prosthetics) said that he had basically never ran a day in his life then within the first year of using his new prosthetic legs, he was breaking records, it seems clear that there’s advantage with these prosthetic legs. He was also using prosthetic legs that were 6 inches taller than what should be proportionate to his body. He was eventually forced to compete with proportionate prosthetics and he suddenly wasn’t the fastest runner anymore. He took the commission to court over the 6” discrepancy claiming he should be taller because he’s black and the proportions the commission was using was only from white and Asian samples.

It’s flawed to argue there will be a change in HR or VO2 if the kinetics change. Energy transformations generate heat, mostly

God dam every video needs to go into the Backstory and history if I wanted that I would look up history of prosthetics we get it you need your ads

what about a marathon? also this reminds me of the carbon shoe controversies

They are literally nerfing amputees. Godamn, never thought I'd say that...

Could you also use the prosthetics to make you calf longer than what it would be biologically?

One thing I think needs to be taken in to consideration is not just times for various events, but the number of people who perform that event. Millions of people train/compete for 100m dash around the globe. Bolt represents the fastest of millions of competitors. The number of people with prosthetics who also compete in the 100m is substantially lower, we should not expect the fastest prosthetic runner to run as fast as Bolt.

The muscles in the hip, that lift the knee, are small, relatively weak, and difficult to strength train, and speed train. Carbon fiber is light as a feather, so those weak little (iliopsoas, sartorius, etc) muscles don't get tired with prosthetics. Hip flexors help speed up "Turnover Speed." Also, the stabilizing muscles alongside the calves, (fibularis brevis, fibularis longus, extensor digitorum longus, flexor digitorum longus, extensor retinaculum, and even the soleus as well) these little muscles fatigue easily, and with that fatigue any springyness is gone from the stride. This mess of little strips of muscle along the tibia and fibula, are extremely prone to injury because of the force coming down on them during a full-out run, and their fatigue factor. You Can't sprain a carbon fiber ankle, so you can recklessly pound the pavement, whereas everyone else has to maintain a certain degree of ankle-conscious caution.

I hope i also have a foot like that because i dont have a purchase im still broken.😢😢😭😭

Underrated

Imagine training as hard as this guy had to not only walk but sprint with two missing limbs, having to adjust to the change in weight, the difference in how you have to move your body, just dealing with the problems that missing two limbs would bring in general, and not only being told that you can't compete but that the same thing you use to help mitigate your disability means you're cheating. Absolutely shameful.

Good

Saying that we should see the energy saved reflected in metabolic factors is an assumption, not a fact. If a runner had become use to pushing as hard as he could to reach a point it doesn't matter whether the prosthetic conserves more energy in the kinetic-potential-kinetic cycle, he still is pushing his body just as hard, only more of his energy is going towards movement than the competition.

A lot of good reason and evidence

They absolutely give an advantage. Stronger restoring force

If abled bodied runners absorb shock more doesn’t that make them slow down? Also the argument that prosthetics exert less force accounts for speed acceleration… To me theres a visible advantage!

那是科技在跑步不是人在真正的跑！

I'm going to abuse this law until everyone regrets that they are born the same time as me.😂

I felt like they are advantages, simply because even though those people are a really small minority they are still well presented in the sports I feel like. They also have less muscles to train and can focus on less. But I guess my intuation was wrong

Amputees should be allowed to compete. Let them run jump, hop etc.and as they place, put them in sub categories ( one prosthetic, two prosthetic etc. ) Those without prosthetics would get the win for their categories and those with prosthetics would get the win for their categories. As individuals with prosthetics compete more then separate their category so as to not to fill up the places for people without prosthetics. So if two men qualified for a top position, one without prosthetics and one with both should be giving a spot and the opportunity to win in their own category.

You got to appreciate the irony that the people without legs run the fastest.

LET ME SEE IF I'M UNDERSTANDING THIS RIGHT, IN A COMPETITIVE 'RUNNING ' EVENT, A DOUBLE AMPUTEE HAS AN 'UNFAIR ' ADVANTAGE ?

Sounds like an advantage to me

Here's a better no debate solution, just have separate league for those with prosthetics.

hot take, but running blades are cheating because anyone who'd want to be a famous athlete would obviously cut off their legs.

I think it is kinda an obvious advantage, Norm Macdonald made jokes about it, but he was right. To have metal springs designed for running - instead of multipurpose meat and bone that needs blood pumped in, needs to get trained, can get hurt, gets tired - is a beyond obvious advantage.

I think we should make a separate division for full blown cyborgs. I was to see what the pinical for flesh and machine melded together can acomplish.

Oh ya it’s an advantage to be crippled 😂

The blade Gunner 🔫

Weakness of the flesh rant begins lol

my friend wants to be amputee

South African dominance of the 400

Pistorius dedication and hardwork is the main reason, rather than technological advancement

Imagine losing ur legs

It all comes down to one simple solution. Let amputees compete with other amputees. Let trans compete with trans. If a guy ran 100m in 9 sec flat with artificial legs, people are not going to recognise it as legit world record. So whats the point. Let them have their own competition.

He has new feet that will out live any human any time and that’s not cheating?? Get real bro don’t get science what does metabolic changes have to do with feeling pain on your ankle and feet which he clearly has none his legs don’t even have joints to grease or wd-40 it’s a spring, if they’re gonna compete like this in the Olympics I’ve should’ve chopped my legs off 10 years ago and got my half robot body to first place

I ran the 32 hundred in track this is cheating, your feet and ankles start to hurt which cause you to slow down. What metabolic difference?? You don’t need science to notice that his feet are now indestructible(feels no pain or fatigue)

But his legs don’t hurt

The one dislike is from a person who doesn't believe in science

i mean something already took his legs now people try to take his livelihood too why not everyone just run in prosthetics

Shouldn't they compete in paralympic competition cuz it's fucking obvious?

Cheating implies a benefit for the "cheater". I don´t see any benefit in losing a limb. :P Respect to all those guys and girls who never gave up.

There will probably be a time where we will remove limbs intentionally to get better at something, so advanced they will get to be.

no expert here, but I think as tech develops in this area, maybe even real athletes start cutting off their own legs for these mechanical ones to race in the future. Seems very dystopian to me.

disqualifying disabled people in the name of fairness

Regular runners are mad cuz bad

Etlv, sti2d on est là