Hi, my name is Jacob Bransky
and I am 17 years old.
My question was how fast a human could
theoretically sprint?
My name's Bryan Heiderscheit.
I'm a professor of orthopedics and 
rehabilitation at the UW-Madison,
and the director of the Badger Athletic
Performance Research Program.
The question was posed of how fast can
humans possibly run.
The current world record by Usain Bolt
is roughly 28 miles per hour,
which is quite fast for any person to even
comprehend, let alone try to
even run faster than that.
Some individuals have speculated that
it may be possible for humans
to run as fast as 40 miles per hour
under ideal conditions and circumstances.
However those ideals and circumstances
require no air resistance
or wind resistance.
No concerns about fatigue-related issues
or many other physiological factors
that may play a role.
So the likelihood of reaching 40 miles per
hour is pretty slim.
Of course, when we're talking about
achieving speeds potentially
that fast,
it's only on level, overground running.
We're not talking about running up hills
or down hills,
or under circumstances that are possibly 
on a treadmill that
may be challenging to do.
There are several factors related to how
quickly somebody could run.
That's why there's only been
one person to run 28 miles per hour.
For example, how long your lower leg
bones are relative to your
overall leg.
How long your foot bones are, how big of
a distance or how far away your calf
muscle and its tendon attach
to your ankle joint.
All of those factors can play a role
as to how fast you
as an individual can run.
And unfortunately, none of that you
can change.
You can't train your bones to be longer,
you can't train your muscle to attach 
closer to your ankle joint.
But you can change certain things such as
how your muscles perform
and how much power they can produce.
That can absolutely increase an
individual's running speed.
