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Hypermobility!

Being flexible has always been seen as a great thing. The more stretchy the better!! The ability to assume any number of crazy yoga poses at will.

Hypermobility however can present its own set of problems.

As we start to understand the body as an integrated unit that relies on the chain reaction of movement for its success, the more we realize that a certain level of tension is a good thing.

The body relies on the eccentric lengthening of muscles to create concentric shortening. All of this has to happen within optimal range and sequence. With a hypermobile person the pretension to create the transformation from one contraction type to another will now not occur in the optimal parameters.

An example of this chain reaction in gait would be of internal rotation of the hip and supination of the foot. As the stepping leg passes over the standing leg it creates relative internal rotation at the hip-joint. This internal rotation will create information and energy for the explode of external rotation of the leg. This also occurs because as the internal rotation runs out at the hip, the pelvis also drives the femur round with it. All this helps the foot to go through supination.

With the hypermobile person, the level of pretension is not there. This means that to get tension for proprioceptive information, energy and to drive the leg from above the pelvis will have to travel a hell of a lot further. If we look down at the foot, by the time it has taken for all the reactions to occur above the correct time for supination has passed. This may mean that the foots effect on the hip in terms of extension may also have passed. This leads to an ineffective gait cycle.

The increased elastic elongation of the muscle has swallowed any tension that may have been generated by the movement.

As we learn to walk as babies we can see the lack of pretension or stiffness regulation in their movement. As we become more effective our joint ranges become more controlled and our internal level of tension improves. This enables the effective transfer of energy and information and hence chain reaction biomechanics to occur.

Hypermobility has implications for energy consumption and speed of movement.  Simply put the larger the joint and muscle range the more energy we dissipate as heat through the splitting of ATP. The larger the joint range the more time it takes to control.

If we see stability as control of movement, rather than the rigidity than the current ‘core stability” trend promotes, then hypermobility may not succeed. In fact rigidity maybe what the body uses for stability in lieu of controlled movement. This would be dysfunctional. Hypermobile joints will interfere with the correct sequence of motion that leads to pain-free movement. It may also force rigidity into other areas of the body to control overall range. This will also interfere with sequencing.

The lessons I have learned from my experiences of working with hypermobile people have always been to find the inevitable areas of rigidity that seem to appear. Also working within ranges that can generate tension in the system, many times this is best done weight-bearing and moving, as this will generates its own tension demands on the system.

Tension too much or too little will also have an effect on the pain receptors and their threshold. Certainly the more tension a rigid area is under the lower the activation threshold of the pain nerve endings becomes.  Although I am not sure of the research into laxity and pain thresholds I would believe a step away from optimal might have some impact.

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Dynamic stretching!

Its been a while since I last wrote so I thought I better had! Today's blog is about dynamic stretching.

To stretch or not to stretch, dynamic or static, these are all questions posed in the fitness industry. Another question is does stretching reduce injury?? This is not a question that I want to get into but instead look at stretching as improving our exercise experience and performance. For me, if we want to increase movement we do this by, increasing movement.

First of all I think we see stretching as a mechanical experience that increase tissue length. To some degree this is true. However I also see dynamic stretching as a neurological experience that increases information flow around the body. So many of the bodies receptors that live in the skin, fascia, joint capsules and muscles respond to change. This would be change in angle, length, tension, pressure and vibration to name a few. Dynamic movement creates constant change, a static change of position only creates one change!

By increasing the movement sphere and therefore information sphere we increase the potential for more movement. As movement increases, so does the ability to increase the range or sphere. A good friend of mine coined the phrase "movement begets movement" I think this is pretty good way of summing this up! So by remaining static we will not increase this sphere or give the body the potential to increase the sphere.

If we look at the information mechanisms in the body and were to look solely at muscles for this information the muscle spindles would be a great place to start. The spindles have two types of Efferent (info towards the brain). One is based on tissue length and one is based on the rate of change of this length. These intrafusal fibres are vital for the feedback loop, through the gamma and alpha motor neurons, that then regulates the stiffness (resistance to lengthening) of the extrafusal muscle fibres and hence successful movement.

By statically lengthening the muscles we are only giving half of the picture. Movement requires both length and rate of change of length information to be successful. Imagine having the GPS system of your car only relay half the information, and the bit omitted was the speed you were traveling at. I think you would be missing a lot of turns!!!

We also tend to only stretch along the fibre direction or longitudinal axis of the muscle. If we look at the mechanical nature of the spindles then this would lengthen and put the spindles under tension but also imagine that when under longitudinal tension adding in perpendicular and rotational tension. This would affect the information flow also. This demonstrates from a muscular perspective why three dimensionality and movement are pretty vital to the stretching or movement enhancing process. Especially as functional movement uses all three planes!

Also we must see stretching as an integrated procedure. In an integrated system such as the body the range of one joint maybe inhibited by the range available to another. If we stretch the joints separate of their function specific chain we may get a different ranges to if they are integrated. In fact a smaller individual range but a larger integrated movement may be the best desired outcome for some joints to avoid tissue stress.

Many factors may also affect the flexibility of the body. These could be stress, diet, disease and eyesight to name a few. If we can understand the feed forward  mechanism of the gamma motor neuron upregulating the stiffness of the spindles and therefore the alpha motor neuron changing the stiffness of muscle fibres, it is easier to see why the above stressors of the system can have such a huge impact on flexibility and therefore the biomechanics of the body!!

I have never understood how remaining still will help us move!!!

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ITB Pain

Today's blog has come about from a conversation I had with a friend of mine who is running the marathon. Like many runners when they get beyond then 10 mile mark he has been struck down by IT band pain.

After consulting the physio he was given some classic stretches for this. General hip ADuction off weight bearing etc. This got me thinking about the predominant view of muscle function and how if we length or strengthen a muscle then it will do this by default.

First of all the ITB and muscles that attach to it maybe individually fine, but when they interact with the foot in a functional position such as stride stance this may change.

A flat or high arched foot may cause excessive lengthening or a lack of lengthening of the IT band and associated muscles. However much we lengthen or strengthen these muscles in isolation, when placed in a functional chain they will be limited or affected by other sections of the chain e.g. the foot. This means that in isolation and decompressed from gravity these muscles will appreciate the stretch but this may make little difference to their ability when back in a functional position during such as during running.

Many times I have treated people who have foam rolled and performed all manner of stretches in an isolated way but to no avail. Once we have found a cause rather than a symptom they have become much better.

The real point here is just because we spend time lengthening or shortening a muscle it may not choose or be able to use the motion or strength we have given it in a functional scenario. It maybe that another part of the system will not allow it to or the muscle or group of muscles have to perform another role because another part of the body has not done its job.

Another example of this would be kyphosis. People send hours retracting the scapulae to 'strengthen' the muscles of the upper back but their postures never change. This maybe because something further down the chain such as the hips and ankles are not able to effectively flex and attenuate the ground reaction and gravitational forces. This means the upper back will have to lengthen to decelerate the spine flexing forward so that the neck and head can remain in a relative upright position. In this scenario would these muscles choose to lengthen and decelerate motion to create relative upper thoracic and cervical extension or, shorten and force the superior distal segments at the cervical to lengthen disrupting head/eye function. I believe the latter regardless of the 'strength' we have given them. One thing we cannot 'beat' or get away from is gravity and ground reaction (unless you have a spaceship of course!!!)

This maybe a reason why people with limited thoracic motion get an anterior head position. The inability of the spine to relatively extend means the neck muscles have to decelerate the forces and end up at lengthened and at end range.

Just some thought out loud really!!!!

Ben

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