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.
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