Flexibility and Mobility

by : Andrew Read

Flexibility and Mobility

Stretching has gotten a pretty bad rap lately. Mostly it has been from the "functional training" camp. They argue that because it doesn't involve movement that it has no place in a training program. There are two main types of stretch receptors - static and dynamic. One works for static movements and the other for dynamic movements. What this means is that flexibility is not just joint angle specific, but speed specific too. To counter that there has been a swing towards what is being called Dynamic stretching or Mobility exercises.

Before I get into it all too much I'd like to take some time to break down the different kinds of stretching and define it.

Flexibility is usually thought of as the end range a muscle is capable of achieving either through assistance (passive means) or under its own strength (active flexibility).

Mobility, on the other hand, is thought of as the range of motion by the limb around the joint.

Hopefully you can see the very big difference between the two.

Another important distinction that needs to be made is between the two main types of static stretching. These are commonly called Passive and Active flexibility. Passive stretching occurs when a limb is stretched by means other than muscular power. Good examples of this include a partner pushing on the limb, or the force of gravity. Active stretching, on the other hand, is conducted using only antagonistic contraction of muscles. A good example of this is a lying straight leg hamstring stretch. The leg must be raised only by the power of the quadriceps and hip flexor. By engaging the antagonists the hamstrings are forced to relax allowing a better stretch to occur. The drawback to this type of flexibility training is that many people are limited in their active ranges.

Interestingly, a number of studies point to a direct correlation between injuries and differences in Passive and Active flexibility.

Dynamic stretching is a term used to describe the range achievable through the use of controlled momentum. Examples of this are side to side or forward and back leg swings and arm swings typically seen in martial arts warm ups. This is different to Ballistic stretching where effort is made to accelerate the limbs and less control is possible due to the higher speed.

In his book Stretching Scientifically, Kurz, uses a wide array of stretching techniques to get the most out of people's genetic flexibility potential. Specifically he combines three main types of flexibility work and places them in order to gain the most benefit from all three.

Firstly he uses Dynamic methods to desensitize the Golgi Organs to the stretch reflex. In essence he uses these to reset the nervous control of muscle tension and length.

He then uses PNF or what he calls Isometric methods to gain specific strength in the new range created. Isometric stretching is also sometimes known as Contract/ Relax stretching and I feel this is perhaps the best term for it. In this type of stretching you use passive means to first assume a stretched position then work through various reps of tensing the muscle being stretched while going into a deeper and deeper stretch position. The effort to increase muscle tension at the end range increases the strength available, negating possible injury risks from extra mobility. (Incidentally, this is why so many yoga devotees have sore lower backs - high mobility in an area that requires large degrees of stability without enough strength to stabilise).

Lastly, he uses static passive stretching to allow the muscle to relax and again, reset the tension limits of the Golgi Organs.

I think, perhaps, that stretching has unfairly been given a bad rap. We should all spend time working on tissue length and quality in our training. In fact, as I get older I appreciate more and more how important it is to keep my range of motion, and my strength through that range of motion. My main thought as to why static stretching has been labelled a poor use of time is that the benefits often take a long time to manifest themselves. But think reasonably about it - to improve strength, endurance, or any other component of fitness you would need to spend a number of hours per week focused on it. Given most people stretch, reluctantly, for 10 minutes two or three times per week at the end of their workouts is it safe to say that it's no wonder that they aren't getting any more flexible?

Try giving the above routine a try for 4 weeks, twice a week as whole workouts - Dynamic for 15 minutes, Contract/ Relax for 30 - 40 and then Static Passive for a further 20. I guarantee massive improvements in your range of motion, posture and how you feel.