Today we are going to find out what scientists
have established as the very limits of human abilities. How fast can we run? How many Gs can we withstand? What’s the ultimate limit of human endurance? I’m Stu this is debunked and we’re here
to sort the truths from the myths and the facts from the misconceptions. This episode is sponsored by Skillshare! How Fast Can We Run? Now this one seems really straightforward
on paper. I say the name Usain Bolt and we move on to
the next topic. After all, he holds the record for the fastest
time over 100m at 9.58 seconds, meaning he ran with a speed of 23.4 miles or 37.6 kilometres
per hour. But that’s just his average, Bolt reached
his top speed around the 60 to 80 meters mark, where he hit 27.79 miles or 44.72 km per hour. Over 19% faster. However, there’s a twist in the tale. Heading back to the 1964 Olympics, Bob Hayes
ran the distance in just 8.6 seconds - almost a second faster than Bolt’s current world
record. But Hayes set the time as the last runner
during the 100m relay, meaning he didn’t have a standing start like the 100m sprint. But, luckily Bolt has also run this leg of
the 100m relay... and his fastest time, is 0.05 seconds slower
than Bob Hayes. Now we know Hayes officially has the quickest
time ever recorded over 100m. But in 1964 the technology wasn’t there
to record his top speed, but we can work out his average, and what we do know is Hayes is 0.58% quicker
than Bolt’s fastest ever time, so we could calculate that Hayes top speed
is 0.58% faster than Bolt’s too. Adding the fact that the cinder track Hayes
ran on is judged to be 2-3% slower than modern rubber tracks we could estimate that the fastest speed ever run by a human
is 46.09km or 28.64 miles per hour But could the humans of tomorrow run even
faster? Well, without wanting to sound like a communist
pig, it could be a case of ’Four legs good, two legs bad’. A 2010 study found that humans aren’t that
effective at running because when we’re sprinting we’re actually
airborne for a surprisingly large amount of time - meaning there’s no force propelling us along. “A human who’s really fast…
...is on the ground roughly 42 or 43 percent of the total stride time. But for a fast-running quadruped it’s two-thirds
of the stride time.” The fastest running quadruped can clock up
speeds of over 30 meters per second - about three times quicker than the fastest humans
in history. Four legs means these animals have increased
contact with the ground while running, so they can propel themselves along quicker. Humans are already blessed with four limbs,
we just don’t use two of them for running - usually. But some people are already running on all
fours. A 2016 study looked at the fastest 100m times for humans running on all fours, and found
that since records of the feat began in 2008 to the setting of the 2015 world record, that
the time fell rapidly from 18.58 to 15.71 seconds. If this progress could be maintained, the
study suggested that humans running on all fours could break the two-legged record by
2048. How Hard Can We Punch? When it comes to hitting stuff really hard,
a 2005 study conducted by Cynthia Bir, Professor of Biomedical Engineering at Wayne State University
has given us a pretty good idea of how hard we can hit. During the experiment, seven Olympic boxers
were tasked with hitting a dummy, which measured the force of each punch it received. On average, these Olympic-level punches landed
with a force of 3,427 newtons. To put that into perspective the average human
exerts a force of only 600N on the Earth. The hardest punch thrown during this study
was a staggering 4,471! This time equivalent to a half-ton polar bear. A similar study from 1985, involving heavyweight
boxer Frank Bruno, found that the future world champion could land a punch of 4096N on a
suspended pendulum in test conditions. From that the scientists involved estimated
that, in practice, a similar blow on a human head would land with 6320N of force. The study equated such a punch to being hit
with a 6kg padded wooden mallet being swung at 20 mph (32 KMH). Such a punch (or presumably the mallet) would
accelerate a head with a g-force of 53gs. Which leads us nicely on to… How Many Gs Can We Withstand? As ever, different humans have different tolerances
for g-forces. Plus the effect on the human body is not just
dependent on the level of g-force, but also the orientation of the body and how long said
g-force is acting on our body. Vertical acceleration can be a problem for
our bodies, as this can send your blood down towards your feet and away from your brain,
depriving it of oxygen. Your brain can only handle about 4 seconds
without O2 before you lose consciousness and most of us would be out of it at 5g in under
10 seconds. Coming at it from another angle, humans have
a much higher tolerance for forwards and backwards acceleration. In the 1940s and 1950s, US military experiments
used a rocket-propelled sled to find out how many Gs a person could handle at a time when
18gs was considered the limit. The poster boy for those experiments was a
Colonel named John Stapp, a U.S. Air Force aviation doctor who put himself through extreme
physical punishment to prove the human body was capable of handling more than conventional
scientific opinion thought possible. A lot more. “His face reflecting the strain, Col. Stapp
is subjected to gravitational pressure 35 times his own body weight” His final, and most famous, test in 1954 saw
Stapp ride a sled that had nine rockets on the back, capable of producing 40,000 pounds
of thrust. When blast off took place, those rockets fired
Stapp to 632mph (1,017 km/h) in just 5 seconds. From that top speed, the sled came to a complete
standstill in just 1.4 seconds. That deceleration equated to 46.2g. Remarkably Stapp was alive but not without
injury - he’d cracked a few ribs, broken both his wrists and was rendered temporarily
blind. Yet, despite his sacrifice, Stapp doesn’t
hold the record. That honour goes to the Captain Eli L. Beeding,
also of the US Air Force, who in 1958 rode a rocket sled on a shorter track while facing
backwards and experienced a deceleration of 83g for 0.04 of a second. “Beeding went into a state of shock and
for a time was considered to be in a critical condition. 5 days later however he was back at work” Beeding holds the record of highest voluntary
g-force experienced by a human. For the non-voluntary record we need to take
a trip… ...to the Texas Motor Speedway in 2003. We’re on lap 188 of the Chevy 500 and Swedish
IndyCar racer Kenny Bräck is involved in a crash at 220 mph (354‑km/h) that sends
his car flying through the air and into a steel post. The deceleration, which lasted for a split
second, was 214g. Giving Bräck the record for the highest g-force
ever survived by a human. HOW MUCH CAN WE LIFT? When it comes to weights it seems like humans
are already close to the limit of what they can lift, bro. The progression of weight lifting world records
hasn’t stopped but there are signs that progress is slowing down. “Today’s weightlifters, including those
that use steroids, are near the limit of human potential.” You see, the body tries to inhibit the amount
a human can lift in order to prevent us from hurting ourselves when we’re trying to show
off at the gym. Essentially, the brain limits the number of
muscle fibres that are activated at a given moment making this limit as much of a mental
problem as a physical one. Top level weightlifters are able to lift about
1,000 pounds (454kg) in a deadlift scenario and just over half that in an overhead lift. But if we want to go beyond that, Schroeder
argues that we’ll need to improve our mental capacity and learn to limit the signals from
the brain that prevent us activating our muscle fibres to the max. If we can do this, Schroeder argues that we
could see weightlifters improve their performance by around 20%. And, given that the deadlift world record
has improved from 457.5 kg to 501kg in the last 10 years, an increase of just over 9%,
it seems like we’re fast approaching the limit predicted by Schroeder. However, if we want to try and pinpoint the
heaviest weight ever lifted by a human, we need to take a fresh approach. That’s right folks, we’re talking the
back lift. This technique is slightly different, in that
it involves lifting a weight on a platform up on your back from a hunched position or
on all fours. This method was used in 1993 by Canadian strongman,
Gregg Ernst, to lift 2422 kg - that’s about the same as adult male white Rhino or 29 average
sized Americans (13 men and 16 women). To give you an idea of how much difference
this technique makes, the 501kg record for deadlifts equates to just 1 female Alaskan
moose or only 6 Americans (3 men and 3 women)! Stay tuned to find the ultimate limit of human
endurance. But first we’d like to talk about Skillshare
who made this video possible. We get a lot of questions asking about how
we make our videos and Skillshare offers classes to get your skills up to scratch with illustration
and animation. We design our animations in Adobe Illustrator
- and you can learn how to make a character of yourself like my Stu in our Flat artwork
style with Mark Rise’s FAST and EASY guide! We then animate our characters and assets
in After Effects. Now if you’re new to this, then join Jake
Bartlett on his comprehensive class for beginners, or dip into another quick guide by Mark Rise,
and once you’ve got the basics down learn how to rig and animate your characters like
we do using Rubberhose! And it’s not only tutorials but you can
take part in class projects and share your work with the community of fellow creatives
for support and advice . We love making our videos for you and can only do it with the
support of partners like Skillshare. The first 1000 viewers who click on the link
in the description will get a free trial to Premium Membership and it’s less than bucks
after that, giving you an entire world of learning will be at your fingertips! Now let’s find out... WHAT’S THE LIMIT OF HUMAN ENDURANCE? For most of us the idea of running a marathon
is great, providing it stays just that; an idea. The reality, of course, is far more daunting
and challenging. Yet as a species we are capable of accomplishing
feats of endurance way more demanding than running 26.2 miles (42KM). Take the Self-Transcendence 3100 Mile Race,
which you might have guessed, is 3100 miles long nearly 5000 km and is the longest footrace
in the world. Competitors have 52 days to complete the distance,
meaning they have to average 59.6 miles or 95.9 km per day. Yet 60 miles a day is nothing for some, with
Camille Herron running 167.8 miles / 270 km in 24 hours to set the female record for ultra
distance running in 24 hours, while the male record holder, Yiannis Kouros, hit 188.6 miles. And, I probably should mention Dean Karnazes,
who has run 350 miles (over 560 km) in 80 hours and 44 minutes without stopping. But what are the limits to human endurance? Well, according to a 2019 study it boils down
to a relatively simple formula - the body is capped at burning through calories at 2.5
times the body’s resting metabolic rate. The RMR relates to the calories the body burns
through when it is, well, resting. For most of us, burning through 2.5 times
the RMR, would amount to 4,000 calories per day. Now, I should point out that the body is capable
of consuming calories at more than 2.5 times the RMR. For example, running a single marathon can
push that to 15.6 times and Tour de France cyclists manage 4.9 times their RMR during
the 23 days of the race. The point, is not that we can’t burn more
calories when we need them, but that over time, our bodies can’t maintain a level
higher than 2.5 times the RMR. The study found that the metabolisms of ultramarathon
runners’ taking part in a 3,080 mile race actually slowed down to bring them within
the RMR limit. Exceeding that limit on a regular basis means
you’ll gradually waste away, as you dip into your own reserves of fat to make up the
short fall. "You can do really intense stuff for a couple
of days, but if you want to last longer then you have to dial it back. Every data point, for every event, is all
mapped onto this beautifully crisp barrier of human endurance. Nobody we know of has ever pushed through
it." The researchers also found that the body cannot
process enough calories over longer periods to go beyond the 2.5 times RMR cap - so simply
upping your calorie count won’t be a viable alternative. Ultimately, it seems the body has to find
a balance for its energy intake and usage when pushed to its limits, and this is it.
