Tuesday, 14 August 2012

Running Posture

Running posture and injury

Clinical Observations

A longer post today that may ask more questions than it answers! Hopefully it will be engaging and encourage the interested reader to explore the practical applications from our discussion.

Running is a skill that must be learned, to perform efficiently. Although we are not taught to run from an early age, the fundamentals are probably hard wired into the brain from about 18 months, when toddlers decide to move around faster. As with many movements they are refined in the early years of development and certain habits and postures are picked up and retained for a variety of reasons.

The human nervous system learns required motor patterns and uses those in the most efficient way possible (this is not to say it is the most efficient way), it’s almost the path of least resistance. In fact it may be down right dysfunctional! For this reason, it is hard to unlearn a motor pattern. In fact, experts who study pain involvement and the nervous system would tell us that you cannot ‘unlearn’ a motor pattern, but you can learn a new motor pattern in preference to an old one. For this very reason ‘poor patterns die hard!’

While the fundamentals of running biomechanics are there for most, if and when we decide to start running as a means of exercise we often carry these patterns over. With continual training we then drive them home as we constantly pound the pavement in an effort to get fitter and faster. Dysfunctional patterns are re enforced with every step.

Before we look at the running posture it’s important to understand we are talking about distance running and not sprint running – the two have vastly different running mechanics.

The major influences;

Posterior pelvic tilt

A posterior pelvic tilt is a common problem. It becomes more pronounced and noticeable as we become sedentary and seated in our day jobs. Poor pelvic position seated may carry over to our athletic and running endeavours.

While there are differences in pelvic angle regarding ethnicity ie; Afro-americans have a more anterior pelvic tilt and Asian countries tend to be slightly more posterior, most of us tend to fall into this position. We then adopt this new position rather than retaining our anterior to neutral pelvic angle developed during our growth and developmental years.

A posterior pelvic tilt tends to reduce boney and myofascial stability around the lumbar spine causing load through the intervertebral disks. This position also ‘locks’ the SIJ, encouraging a hitch through the swing phase during gait. Further to this, lack of extension in the hip is observed. Lack of extension through the toe off inhibits full activation of hamstrings and glutes. The trade off being facilitated quads and hip flexors further compounding the problem. This often reduces firing of the gluteus medius especially the posterior portion being placed on such length in the eccentric position during midstance.

Fig 1. Posterior pelvic tilt causing a myriad of problems

The last big notable problem arising from posterior rotation of the pelvis is over striding. Over striding places increased loading on the anterior structures as they eccentrically load through increased ground contact time. This increased contact time forces the calves to work over a longer period of time, often these are the runners that complain of ongoing calf injuries. This is also a culprit in rear foot loading and ground collision - an area of hot debate at the moment with the popularity of bare foot running (a topic in itself)

Kyphotic thoracic spine

A kyphotic or ‘rounded shoulder’ position may be adopted over time or may be due to a particular disease process (osteoporosis, scheumanns disease) or a predisposition. We will focus on the adopted form.

Lack of extension tends to occur as we leave our developmental years and assume more sedentary postures. It does not occur over night. With rounded shoulders, flexion through the mid to upper thoracic spine occurs ‘opening up’ our facet joints and causing us to become stiff and less mobile.

With flexion in the thoracic spine comes a loss of rotation. Rotation in the thoracic spine is extremely important in the counter movement of the opposite hip/SIJ. As the left hip drives forward from mid to terminal swing phase, the right shoulder and thoracic also rotate to the left, causing a counter rotation. This also assists in preparing the myofascial system to ‘wind up’ and store energy through the right latissimus dorsi and left glute max. Activation of these structures causes closure of the SIJ giving stability to the pelvis. A lack of mobility can therefore cause instability to the SIJ setting up a myriad of problems

Anterior displacement of the pelvis

An anterior displacement of the pelvis typically occurs in those hyper mobile persons or those standing for long periods of time. If this position is adopted during running posture a variety of problems can occur.

If coupled with an anteriorly rotated pelvis there will be impingement in the lumbar spine loading the disks at L4/5 and possibly referring posteriorly down the thighs. Conversely when coupled with a posterior rotation (more common) the hip flexors become so overactive eccentrically trying to control the forward position of the pelvis, the glutes go into hibernation. This causes similar problems to a posterior rotation alone though to a higher degree.

Pelvic stability is often a key factor for this type of runner (posturally speaking)  - usually there is joint laxity about the hip/SIJ and stiffening up of the joint(s) and placing them in a better position often improves dysfunction about this area.

With poor joint stability, increased loading and forces will be taken up by boney and joint surfaces as opposed to connective tissue, which are better designed to withstand compressive and tensile loads. Soft tissues also repair to some degree where as joint surfaces do not!

Anterior pelvic rotation

This scenario is a problem far less frequently from a clinical perspective unless it is a big rotation. This tends to load up the lower lumbar spine causing stiffness and possible impingement. This is also the runner that tends to land in a more pronounced forefoot position, giving the calves and achilles a lot to think about!
The bigger concern is a compensatory kyphosis of the thoracic spine (discussed earlier).

Unilateral rotations of the ilia (including inflare and outflare)

These do present in the clinic and can be either from long term occupational overuse or from an acute episode ie; lifting. Usually they are easy to assess and gain control over. The side that rotates away from the ‘normal’ for that person will usually be the symptomatic side.

BUT, if the rotation is not attended to early, compensatory patterns can set in making the treatment process a little more complicated.

Final Thoughts

It always amazes me that most sports even at a club level will consider form and biomechanics as an important of the development of an athlete yet running is an assumed skill. Running is a skill and similar to all skills it must be developed. Runners at national level do not practice form - it is a case of physiology and ‘just going harder’ unfortunately, this does not always work.

The question might be, are these runners at this level because they are more economical and efficient and adopted good patterns early on, or did they develop this as a way to get faster, fitter etc?

Treatment for the running athlete will be addressed in a future post. Until then…..

Happy Running!

I am happy to discuss further if anyone would like to contact me

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