The mechanics of pulling a
heavy barbell off the floor is controlled by the interaction between
the musculoskeletal anatomy of the human body and the weight on the
bar. Briefly, the bar must be over the middle of the feet, and the
shoulders must be slightly forward of the bar, with the hips high
enough to facilitate this position, with the bar pulled vertically
over the mid-foot off the floor, as discussed in detail in Starting
Strength: Basic Barbell Training 3rd
edition. The heavier the weight, the more
efficient the mechanics must be to finish the pull, and at 1-Rep-Max
weight the configuration of the pulling mechanics will either be
efficient as the bar comes off the floor, or the pull will not be
completed.
A 1RM pull is a 1RM
deadlift. A 1RM clean is a submaximal pull, since it is between
50-70{32c02201c4e0b91ecf15bfd3deecd875caca8b9615db42cfd45ce3d8de8d0829} of the deadlift, depending on the lifter. It may be the most
you can clean, but
it’s not the most you can pull.
And since it is submaximal, a clean can tolerate deviation from these
perfect mechanics. A 1RM snatch is even
more submaximal, and
can be pulled damn near any way you want to pull it. Add reps and you
are taking weight off the bar: a 5RM deadlift is a submaximal pull,
by definition. A set of 2 snatches is light compared to a 1 RM
deadlift, even if you can’t do a third rep. But whether a deadlift,
clean, or snatch, even if technique is perfect (and it never is
100{32c02201c4e0b91ecf15bfd3deecd875caca8b9615db42cfd45ce3d8de8d0829}), force production – strength – is the limiting factor for a
limit attempt.
The
deadlift stops at the mid-thigh, but the clean stops on the
shoulders. A deadlift can take 10 seconds to lock out and still be a
completed deadlift, whereas a clean must be racked in a little over 1
second, or it’s a miss. A heavy clean cannot be rowed into position
after the pull stops at the mid-thigh, because the rowing muscles are
inadequate to the task. The lifter must get the bar moving fast
enough to make it fly upward high enough to catch it after the
pulling stops, and that must happen before the bar gets to the
mid-thigh, where the lifter has already used all of the hip and knee
extension available.
The difference between a
deadlift and a clean or a snatch is acceleration:
the rate of change in the velocity of a moving object.
Acceleration
is proportional to the force applied to the object and the mass of
the object. If you want to accelerate the
barbell to get it moving faster, you’ve got to pull it harder –
with more force. If
you want to accelerate a heavier barbell, you’ve got to pull it
harder – with more force.
And the higher you want the bar to travel, the harder you have to
pull it so that it gets moving fast enough to travel the longer
distance – again, more force.
A clean must be
accelerated in order to be racked on the shoulders – it must be
moving fast enough to attain sufficient momentum
(the product of the mass of the bar and its velocity) to continue
upward after the feet break contact with the floor as you drop into
the catch position. The “fast-enough” part – the
velocity-part
– of the momentum is the result of acceleration,
which is
always and forever a function of force production – strength.
Getting
under the bar quickly obviously improves the efficiency of the pull
by reducing the distance the bar falls after its upward momentum is
exhausted, but if the bar doesn’t get pulled high enough, the
quickness of 90 cats will not let you clean the bar. The bar gets
pulled high enough because you were strong enough to accelerate it –
get it moving fast enough to have sufficient momentum to fly up as
you whipped it through the middle of the pull, so that it continues
upward as you come down into the rack position.
Which
means that force production is inherent in the clean, and the
deadlift always contributes to a heavier clean. It
should be obvious that a lifter with a 500 deadlift can clean more
than the same lifter with a 200 deadlift, or a 300 deadlift. What is
not obvious is how strength is converted into power,
which is strength displayed quickly.
The ability to produce a rapid efficient muscle contraction is
largely controlled by genetic endowment, and the standing vertical
jump test (SVJ) measures this capacity. Not everybody is explosive,
and explosive capacity is not particularly trainable. But everybody
can clean, and since cleans require acceleration, everybody can do a
movement that requires and practices acceleration.
The
way the acceleration is accomplished is with leverage
– the use of moment force
by the musculoskeletal system. This is discussed extensively in the
Blue Book, so I’m not going to take the space here to explain it in
that level of detail. But just to jump right in, probably the most
familiar use of leverage is the crowbar. A long moment
arm (or
lever arm) multiplies the force applied against the short moment arm
and allows you to pull the nail out of the board with the strength of
just your arm. Less familiar is the opposite use of the leverage, as
seen in the medieval siege engine called the trebuchet:
a large amount of force applied through a short moment arm can
accelerate a lighter load at the end of a long moment arm.
Both
systems rely on the rigidity of the segment transmitting the force –
rubber crowbars don’t work, since they “leak” force. And both
systems rely on the differences in linear arc length traveled by the
ends of the long and short segments. Since the segments are rigid,
they travel through the degrees of angle at the same angular speed,
but the linear
speed traveled through the linear distance at the ends of the segment
are different. The short end of the crowbar may only move 2 inches,
while the long end moves through 24 inches of arc in the same time.
Thus, 12 times the distance at lower force concentrates into the same
force expressed across 2 inches at the short end, enough to pull the
nail. This is known as mechanical
advantage.
The
long arc was covered faster than the short arc, since 24 inches was
covered on the long end in the same time 2 inches was covered on the
short end. Therefore, if we apply sufficient force to the short end
of a lever, it moves the long end much faster, since they cover the
same angular distance while moving through different linear
distances. Like stepping on a rake, the trebuchet works on this
principle – look it up, it’s easy to understand.
The
human hip is a first-class lever, with the ischium the short segment,
the spine up to the shoulders the long segment, and the hip joint the
fulcrum. The short segment (high force) operates the long segment
(high velocity). The clean is accelerated with the moment arm that is
created between the hip joint and the bar – the horizontal distance
between the fulcrum and the load. If
you’re strong enough,
you can use the short moment arm to “whip” the long moment arm –
and the bar – up through the pull, accelerating it until the point
where your feet break contact with the floor, where the high momentum
you created causes the bar to continue upward as you drop down and
catch it on your shoulders.
An
efficient clean holds the back as horizontal as possible –
“shoulders out over the bar” – for as long as possible, so the
bar can be accelerated for more of the pull. This is why the clean
should start with high hips, because high hips is a more horizontal
back with the bar over the mid-foot balance point, a longer portion
of the pull spent with this longer moment arm accelerating the bar,
and more bar speed as a result of the longer acceleration.
In
contrast, the deadlift doesn’t need to be accelerated, just lifted,
and slowly is just fine. So the back in the deadlift becomes
more vertical
from the time it leaves the floor until it locks out at the top. At
deadlift weights, the shorter the moment arm between bar and hip, the
less moment force it takes to lever it up to lockout, so dumping the
moment arm length by getting more vertical is efficient.
Both
the clean and the deadlift must start with the bar directly over the
mid-foot balance point and the shoulders forward of the bar, for
reasons explained in the book. The difference is what happens after
the bar leaves the ground: the back stays horizontal for a while in a
clean, and immediately gets more vertical in a deadlift.
What
we have discovered over the course of teaching the clean to thousands
of people over the last 17 years is that lower hips in the start
position of the clean – as is commonly taught by weightlifting
coaches – results in a shorter ROM pull than the same weight pulled
with higher hips. We have photographic evidence of this, and we
demonstrate it at every seminar. It’s merely the application of
simple mechanics to the lifts, instead of mindlessly teaching it the
way it’s always been taught.
The
bottom line is that if you want to clean big weights, you have to be
strong enough to accelerate the bar. You have to generate enough
force to get the bar moving fast enough, you have to be in the right
position to accelerate the bar, and you have to be strong enough to
hold your back flat while you’re doing it. Technique is important,
but correct technique only allows you to clean what you’re strong
enough to accelerate. There are a couple of different ways of getting
strong, but heavy squats and deadlifts are legal.
