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.