LESTER HOLT: In a game played by big men, NFL offensive linemen
are some of the biggest of all.
Whether they're blocking for a running back or protecting the
quarterback, these giants of the O-line
know how to use size to their advantage.
ORLANDO PACE (Former NFL Tackle): Man there's some big guy's
that play in the NFL, especially on the defensive line.
So sometimes those big guys just hit other big guys
and you're trying to move and the low man really wins.
HOLT: Who wins the battle of the gridiron goliaths?
According to the laws of physics,
it's the player who stays the lowest and masters the concept
of torque--which is the tendency of a force to make an object
rotate around an axis.
Dr. JIM GATES (University of Maryland): A torque is anything
that causes another object to spin.
HOLT: In the NFL, we see torque whenever one player collides
with another, causing him to rotate or spin.
What's key is the distance of the force from the rotation
axis--this distance is called the "lever" or "moment arm."
Dr. JIM GATES (University of Maryland): So where the force is
applied to an object determines whether there's a torque.
If I hit dead on, no torque, if I hit a little bit to the side
and cause spinning, I have a torque.
HOLT: To counter this rotational force,
coaches at all levels teach players to stay as low as possible.
TONY SCHMITZ (University of Florida): Get low, get low now.
HOLT: Tony Schmitz is a former Division One college football
player and currently a coach for the Newberry High School
football team, but as a mechanical and aerospace
engineer at the University of Florida,
he understands the physics behind staying low.
SCHMITZ: Coaches often talk to players about staying low and
there is different phrases they use like the low man wins,
because if I can have my center of mass low and exert my force
against somebody with their center of mass high,
I'm more likely to push that person over and win the battle.
HOLT: A player's center of mass,
often referred to as their center of gravity,
is the point on a body where mass is most concentrated.
SCHMITZ: So the center of mass is the average
location of mass for any body.
For a lineman, for example, that center of mass is usually
somewhere near the navel.
HOLT: When a player crouches, his center of mass is lowered.
Dr. GATES: And that's one reason you want to stay low because,
if you're low, you're taking advantage of the laws of physics
that says that if you can't get to my center of mass,
it's hard for you to make me rotate.
PACE: The low man wins on this one,
that's the key.
HOLT: Consider Orlando Pace, 7-time Pro Bowl offensive tackle
with the St. Louis Rams who stands 6 foot 7, 325 pounds.
His center of mass is located just above his hips.
By crouching, Pace not only lowers his center of mass but
he's now in a position to impart a bigger torque because he's
able to hit upward on his opponent.
SCHMITZ: By hitting on the rise we can actually increase the
torque that we applied to a body because as we start low there is
a low moment arm from where we apply the force to the ground,
but as we get higher that moment arm increases
and we are applying more torque.
HOLT: As Pace rises from the crouched position,
the distance between his opponent's pivot point and the
location where Pace applies the force increases,
allowing him to impart a higher torque on his opponent.
PACE: To move a guy off the line against his will is probably the
biggest success as an offensive linemen you can do
because that guy is trying to come forward,
you're moving him back, as an offensive lineman
that's our touchdown.
HOLT: And in a game where the low man wins,
that success comes one push at a time.