To improve movement, each traceur/freerunner
should have a firm understanding of the function of the kinetic chain
and its relationship and interaction with ground reaction forces and
momentum. Once this understanding is developed a logical progression can
be implemented to correct and enhance movement skills.
Ground Reaction Forces
The foundation for all movement must reside in the knowledge that
movement is completely dependant on the ability of the athlete to
utilize and manipulate forces, most importantly the forces that interact
with the ground (ground reaction forces GRF).
The ability to powerfully apply force
to the ground is crucial to movement, but is only part of the equation.
We must also be able to efficiently deal with the force the ground
supplies back into the body, because in reality, these are the primary
forces that propel and stop the body.
Thanks to Newton's laws of motion, we
know that for every action there is an equal and opposite reaction. With
respect to movement, this means that when we push against the ground
with X pounds of force, the ground is going to push back with that same
(X) amount of force (dependant upon the surface).
FIFO (force in = force out) response.
When you further examine the FIFO response you will see that the harder
you push into the ground the harder the ground is going to push back.
This concept will become increasingly important later when we start to
discuss acceleration and deceleration.
During movement we must not only be
concerned with the magnitude or amount of force we produce, but also
with the direction of application of the force vector. For the purposes
of this article, a force vector will be defined as an imaginary line
that defines the direction of application of a force. Understanding
force vectors will allow us to visualize the forces that we apply and
receive.
Note:
When you push against the ground with your foot, you are creating a
force vector dependant on the direction of push. In response, the ground
is going to directly oppose that force vector with its own. It is
important to visualize both vectors when we start to analyze the
movement.
We must know how to appropriately
direct forces to create clean movement. If we misdirect the force we
apply to the ground, the resultant reaction will not efficiently help us
create or deviate movement.
Although the foot is the point of
contact with the ground, it does not determine the force vector created
by the push. Rather, one must consider the segment of the leg from the
knee down to the foot. It is this segment that will determine the
direction of that vector.
One must also consider the centre of
gravity (COG). The relationship between the location of the COG and the
angle of the GRF becomes very important during movement.
Once again we are reminded of Newton's
laws of motion. Newton stated that a body will stay in a constant state
of motion (or motionless) until it's acted upon by an outside force.
Typically what we see (when the body is motion) is that when the force
vector created by the GRF opposes the direction of travel of the COG we
create a breaking or decelerating moment which disrupts the current
state of movement.
This becomes apparent when an athlete
tries to rapidly decelerate and they sound like a Clydesdale stomping.
They are creating substantial breaking forces to rapidly decelerate
their COG. These forces directly oppose the COGs direction of travel.
Likewise, when the force vector angles
the same direction as the COG, we are producing propelling or
accelerative forces. If you were to analyze a sprinter coming out of the
blocks you would notice that they maintain a significant forward lean
for 8-12 yards (some more some less).
This forward lean puts the lower shank
of the leg at a close angle to the ground. This angle creates a force
vector that angles the same direction as the direction of travel of the
COG. This means that they are propelling, or pushing the COG forward.
If we examine jumping from a stand
still we see that the GRF's are parallel to the COG and perpendicular to
the ground. This creates lift or vertical displacement since you are
pushing the COG up.
*Develop A Strong Vertical Jump!
An explosive vertical jump is important to nearly all athletes
regardless of their sport of choice, especially Parkour/Freerun.
With this discussion on how GRF's affect our direction of travel, we can
start to see how minor changes in our GRF's can cause small deviations
in the path of or COG. This becomes an issue when this path is not
consistently directed toward our goal.
The next step of the process lies in
understanding how we must configure the body to appropriately apply and
utilize ground reaction forces.
I have divided cutting into 5
parts. This is a particularly remedial breakdown of movement where I
will be discussing the FUNDAMENTALS in an extremely controlled
environment. Once these fundamentals are ingrained we will begin to work
on how they apply to a more realistic chaotic environment.
Start by setting 6-8 cones up in a zig
zag pattern so the cones allow 6-8 steps to be taken and form an
approximate 90 degree angle to the next cone.
Terminal Stance
The terminal stance is the bodily configuration used to optimize the
biomechanics of the body with respect to cutting. There are 8 key
elements to this stance.
- The Feet: You should be on the
front half of the foot on both feet with the heel slightly elevated. I
refer to this as up on the platform. Both feet should be facing the
cone with the foot opposite of the direction of the cut in front.
- Lower Leg Angle: This is
somewhat dependant on your anatomy. Generally we want the back leg
angle to be much lower than the front (with respect to the ground).
This will allow you get you hips low and actively use them when you
push. The front leg should be angled slightly back toward the body.
This leg will act like a shock absorber, and will create a breaking
moment to help absorb the deceleration of the COG (centre of gravity).
Furthermore, this will allow the musculature of that leg and the hips
to preload and reactively respond during the push phase. It should
also be noted that the lower legs should have a perpendicular medial
lateral reference.
- Upper Leg Angle: You should
approximate a 90 degree angle between the front and back thigh. This
will help determine foot spacing front to back.
- Hips Low: Lowering the centre
of gravity will help in the manipulation of the momentum of the body.
In generally, when we lower the COG, we what to use the hips, not the
upper body (flexion at the waist). I like to use the analogy of what
corners better, a sports car or a school bus? The sports cars COG sits
much lower, which allows it to corner much more efficiently.
- Balance: The body must be
balanced. The COG should be centred between the feet front to back and
side to side. This will allow for the effective manipulation of
momentum and ground reaction forces (GRF).
Note: Do not allow the hip of the plant leg to push out lateral.
- Upper Body Angle: The upper
body should create an angle slightly less than 90 degrees with the
front leg. When closed or opened, the hips will not be positioned in
an advantages position for the expression of force.
- Spinal Alignment: The spine
should stay in a neutral alignment. Avoid rounding the back.
- Head: The head should stay up.
Lowering the head can cause rounding of the back and over flexion at
the waist. Do not focus on the cone with your eyes, rather look toward
the horizon.
Start by learning the terminal stance.
Spend time educating the body on how it feels.
The Approach
The approach is vital
since it leads into the terminal stance.
- Approximately 2-4 steps before hitting the terminal stance, you
need to begin lowering your centre of gravity (lower using the hips
not the upper body).
- Use minor stride adjustments to hit the terminal stance stride
length. Avoid jumping or reaching to get to the cone and the stance.
- Decelerate as you lower your centre of gravity. The amount of
deceleration is dependent on your mechanics and leg strength. Weaker
athletes may not be able to decelerate as quick. Furthermore, when the
COG resides to high, momentum may make deceleration more difficult.
First start 2-4 steps out, walk and
lower the COG as you come into the terminal stance. Once this is
comfortable, begin at the first cone, walk and hit the terminal stance
at the next cone.
Knee Drop
Assume the terminal
stance. The body should be configured as described above. At this point
in time there should be no medial or lateral tilt to the lower leg. If
we were to maintain this position, hip and knee extension would cause
elevation of the COG or posterior displacement. Since our goal is to
move the COG horizontally toward a cone that resides in front and to the
side of your current position, we must change this bodily configuration
somewhat.
The front leg must be tilted medially
toward our destination (typically 15-20 degrees, but who is measuring).
Do not rotate the foot, rather keep it pointed toward the cone, and
rotate the leg in and toward the next cone. This will allow the push to
project the COG toward the next cone.
Practice the approach into the terminal
stance. On cue, drop the knee and hold the position. Once balance can be
maintained, approach the cone and hit the terminal stance with the leg
rotated in.
Triple Extension Push
Just as it is better to absorb force through multiple joints, it is
better to express force through multiple joints. Since we know that
extension means to straighten or increase the angle at a joint
structure, we can realize that triple extension must refer to 3 joints.
In this situation these joints are the
hip, knee, and ankle.
When we are in the terminal stance, we
have flexed and loaded these 3 joint structures. With the knee tilted,
simultaneous triple extension will effectively push the COG toward the
next cone.
When correctly orchestrated, this
triple extension can be the most powerful motion the body can produce.
This has been demonstrated by the huge power outputs measured by lifters
performing Olympic lifts (which are based on this triple extension).
This motion needs to practiced and perfected.
Here are some ways to practice this
motion.
Start in the
terminal stance (with the front leg rotated in). Explode
through triple extension of the front leg and jump toward the next
cone. Land on the opposite foot and regain your balance. Focus on the
simultaneous triple extension and complete extension at the hip (which
is many times not fully completed). Also work on rapidly regaining
balance on the landing (which will be on one foot).
Stand on one
foot. Jump diagonally landing on the opposite foot. Absorb
the landing through the hip, knee, and ankle and make sure you land
with your hips pushed back and your knee behind your toes. As soon as
the decent terminates, explosively triple extend and jump back to the
starting position. Practice this off both feet. The intensity of this
exercise is determined by the distance of the jump.
Younger or weaker athletes should not
leap as far forward as more conditioned athletes. If there is a
problem controlling the landing, than the initial jump was too great.
I would like to note that these drills
are designed to teach the execution of the triple extension, and will be
modified to properly propel the COG during the next drill.
First Step
The first step is made by the back foot coming out of the terminal
stance and should be directly toward the destination, which in this case
is the next cone. Since we know the shortest distance between two points
is a straight line, the location of this step could potentially add
distance to our path if misplaced.
Although we practiced jumping off the
cut to execute triple extension, we truly do not want to lose contact
with the ground when we cut. This is so for two reasons. First, when you
lose contact with the ground you lose the ability to change direction
(since you are in the air, you are going to go the way you jumped).
Secondly, when we talked about moving the COG in a straight line toward
the next cone to decrease the distance travelled, we need to also
consider vertical oscillation.
The first step needs to be a
comfortable stride. Over-striding will cause a breaking action and will
hinder forward momentum. Likewise, under-striding will not allow for
full triple extension off of the cut. This size of this step needs to be
worked with, as it will be different for each person.
In addition the first step, should
initiate from the lead shoulder. By this I mean that when coming out of
the terminal stance, the lead shoulder should push toward the
destination as the lead leg executes triple extension. If this is not
performed properly, the shoulders will lag behind the hips on the push
causing a momentary lag as they are catching up.
Final Words
Take time learning these techniques as they are fundamental to
multidirectional movement. These mechanics need to be reflexive in
nature to truly have on impact on confrontation chaotic movement.
Time spent learning the basics will pay
off tenfold in the future.
