The skill of movement determines the way we
interact with the environment we are in contact with. Here at the Barefoot Performance Academy we say ‘“To walk well you have to know how to run
well. To sprint well you have to
know how to run well. To run well
you have to know how to move and jump well.”
With good form running our architectural
design (the way our bodies have evolved) allows us to utilise what can only be
described as a masterpiece of design. It is running skill that develops our organism to excel
at all other movements. (The study of children’s movement development explains
this). This movement development
is no coincidence. We were born to run.
Without this skill we wouldn’t have survived as a species.
This posting is to delve a little into
functional anatomy and the biomechanics that influence the role of the
hamstrings.
In our industry we are divided upon running
technique and I hope this posting will shed some light on what good running
form truly is and why it is a skill that needs to be coached well in. I have studied barefoot science, which
desired foot strike is on the ball of foot (BOF). It must be said that you can heel strike when barefoot running
to. I must also add that we
are not born with shoes on our feet, this suggests to me that our body’s true
alignment is design around barefoot.
So to describe a small part of the good
form running action, to explain the major role of the hamstring we will start
at the foot strike in the running phase, otherwise known as the support or
yield phase.
As the BOF touches the ground and upon
loading with full body weight (BW) with the general centre of mass (GCM)
directly above the BOF, the heel travels towards the ground providing two major
roles.
Firstly the start of the triphasic nature
(stretch/shortening cycle) of the achilles and calf structure and secondly it
provides the space, a gapping effect, for the lower limb (Fibula/Tibia bones)
to travel forwards via the ankle joint which travels over the sub talar joint
to create ankle dorsi flexion. It
is only when ankle dorsi flexion is created that the magic of the calf muscles can
be utilised to full potential.
A functional foot produces potential energy
through the arch of the foot being compressed and stretching the plantar fascia. At the same time through ankle dorsi
flexion the foot is dynamically stabilized by the Posterior Tibialis (PT) and helps
produce foot rigidity due to the positioning of its attachments, creating a
propulsive lever to assist the plantar fascia to utilise its plyometric spring
from the foots fixed position on the ground (as beautifully described in
3dhumanmotion’s blog).
An ankle and foot with mobility issues
won’t achieve full dorsi flexion as described above. A great test for full range ankle dorsi flexion is the
barefoot deep squat (heels are unweighted but just touching the ground
throughout the whole movement sequence whilst keeping good posture).
Still traveling in dorsi flexion the achilles
is being stretched through its Plyometric action, as is the whole calf
structure whilst the tibia travels fwd over the foot. Deceleration primarily comes from the soleus, decelerating tibial
forward motion and ankle dorsi flexion due to its attachment below the knee. This creates knee extension as the femur,
the hip and the rest of the body now travels faster over the decelerating lower
limb. (GFR is primarily being
dealt with by the Plyometric actions of the quads and hip structure to hold
posture true to the vibrations being experienced). The gastroc still lengthens
due to its attachment above the knee to utilise its full Plyometric potential
and the timing with the hamstring pull.
The wonder of the calf, what I call
ultimate strength, deals with ground force reaction (GFR) by starting the
Plyometric action on the yield phase (foot strike), whilst allowing
acceleration through dorsi flexion (this is helped via momentum forces as the
hip and the rest of the body travels fwd which then explains why the skill of
running is so important with the positioning and pivoting point of the GCM that
works with the architectural design of humans), then decelerates to allow more
stretch through knee extension to explode from the rigid foot it created to
lever from. Wow!
Knee extension cues the hamstrings into
their roles through lengthening them due to their attachments below the knee,
which have been relatively silent by getting a free ride due to role of the calves, quads and hips to this point in the yield phase, and most of all unbroken
momentum. In a ‘nano’ second a
Plyometric stretch is applied through knee extension to action the pull to get
the foot off the ground. The skill
of running pivots on this one action.
Without it, timings are out and compensations appear. How to change it is helped by a number
of other pivotal actions, such as cadence, muscle/tendon tone, ankle dorsi
flexion and the big bang hip extension.
Now I must explain that the hamstring in
bad form running, which is GCM landing behind the foot as in heel striking, the
hip joint will rapidly anteriorly rotate to compensate for the braking force
experienced in this type of running.
This activates the hamstring from the hip joint utilizing the bend
pattern and changes the role of hamstring to a force muscle not a
velocity one as it has to deal with breaking (decelaration) forces. It then doesn’t
allow true hip extension (looks can be deceiving). The decelerating hamstring is marred with the push off and
all its injury associations.
By the GCM landing behind the foot changes
the biomechanics. The forces in
this example in heel striking, when running, are experienced over a longer period
of time and with different joint torques due the change in postural shape. This imposes greater joint torques at
various joints, which unevenly spreads the load through our kinetic chain. This explains how injury is a
cost effect of bad running form.
Back to good form and you just look in awe
of the design of the sequencing of our lever system to action the Plyometric
stretch in the hamstrings. But on
the other hand how easy this lever system can be overridden by weaker lever
systems to compensate when alignment is out.
The pull up of the foot is so important
because without this timing optimal balance will be lost in the air and joint
torques will be effected as the body shape and muscle sequencing changes
therefore disrupting the next foot contact to fall prey to bad form. Then the snowball effect rolls on
accelerating fatigue and all its associated problems. This explains the VO2 max gains made in a session through
the POSE method filmed by the BBC.
The whole body is a tuning fork to the forces
we utilise to move us through space.
The elastic energy storage system we utilise, I believe is better
described as a floatation system not a spring or propulsion system. The elastic qualities and the
stiffening and dampening qualities of muscles provide the right action to glide
us across our environment for running; the actioning of the hamstrings has
enabled the perfect timing for the weight shift. (This said, it is the understanding of gravitational torque
we need to learn to master the skill of movement.)
I hope now ankle dorsi flexion and knee
extension has painted a unique picture and explains the architectural design of
why the hamstring and gastroc intertwine one another and why they are biaxial
muscles.
Good form running can map out the archetypal
design of muscles, their fibre lengths and angles. This at my practice has delivered me a clear understanding
of common injuries. However this
science only works if good form is present. Facts can be built up on decelerating hamstrings, as I have
explained in the action due to breaking forces. It is still called running and I believe has caused
confusion in our industry.
Is heel striking all bad? Well for some the desired action is
appropriate in running and specific sports demand it when being over
reached. But if your kinetic chain
is always set up to fire in the heel striking sequence then you are limiting
the skill of your body and therefore your skill as an athlete. Not to mention increasing your injury
rate. (80% of runners get injured
on a yearly bases – ACSM 2005)
I was asked, for a training strategy, if hopping was close to the
biomechanics of running. Well it
really depends if the hop is being performed with good running form in mind. Good form is based on Posture and
rhythm.
Posture and rhythm change to the constant
variation of the forces we experience at any given point. This is where the muscles become the
brain for the tendons.
What is obvious to see is in our gear
changes in motion. We see dramatic
changes in our shape and this is subconsciously driven depending on the forces
we are experiencing. Gears allow
more efficient joint torques to channel the load through our kinetic chain,
like gears in a car or on a bike.
For instance, a horse has four gear changes in motion we humans have three. Walking, running and sprinting present
very different biomechanics (postures and rhythms) and should be coached like
wise.
The beauty about motion is we all have the
hardware and software to experience fun, injury free running; we are born with
it. If you lost what you had as a child, all you have to learn is how
to turn it back on with the skill of running.
References:
R. Lieber – Skeletal Muscle Structure,
Function, and Plasticity
Dr Romanov – POSE Method of running
Vivobarefoot Coaching Programme
About the author
Rollo Mahon has an academic background in Sports Therapy. His academic journey has led him through various athlete performance accreditations where he has specialised in the science and biomechanics of barefoot running. His search has been to find the solution to injury free biomechanics and therefore better performance, which has been cemented by the science of barefoot running.