HI All,

Physiobase has hit it on the head when it comes to stretching. Stretching is an isometric CONTRACTION. Not a lengthening!

I can almost hear the "but I was taught that stretching will help lengthen the muscle and reduce pain by increasing blood flow and reducing splinting." I am sorry to say this to you, and I may sound like a blaspheming Cathar, but stretching does not exist! At least as we have been taught.

Ok... lets first talk about muscle length. Who knows what an appropriate length is? Take the glute med for instance. Can we even measure it? Do we take into account the muscles that support its actions? Do we take into account the muscles that oppose its actions? Is the length measured by range of a joint (and again we must take into account the previous questions). Is the range of an athlete supposed to be different from the ADL recommended range? Is increased tone a sign of shortened fibers? Is a pain sign the absolute limit of a muscles length? It has been discussed by researchers that neither fiber length nor physiologic cross-sectional area can be deduced on gross muscle inspection. Are we wasting our time in trying to answer these questions? I personally believe that the muscle knows what length it has to be at. (see below for why)

Second: Muscles are not rubber bands! There are two components to the muscle, the elastic and the plastic portion. The elastic portion can be considered tendon, cell membrane, fascia, etc. and the plastic component is the skeletal structure of the muscle cell. What is the skeleton structure? That would be the filaments inside the cell of course. Just as you cant make your arms longer by letting them dangle at your sides with 40lbs weights at the end, neither can you change the length of the muscle cell by "stretching" them. (but there is a way around this... READ ON! :b ) THEN there is TITIN! Ahhh beautiful, sweet, enigmatic Titin. Titin is a protein that limits the length of the sarcomere in passive tension. (it can be thought of as the ligaments to the bones so to speak) But here is the rub... in vivo, it only resists low force tension and not high force tension. But can the muscle be forced to experience high force tension before the stretch reflex is activated or bony end feel is achieved... WITHOUT injury?

Third: Mmmmm Brains. What about that long piece of brain that goes down our backs? (ok so it is my opinion that the spine is just a very long piece of brain ) There are reflexes there that inhibit or encourage contraction. So we must not forget that the stretch reflex MAINTAINS the status quo of muscle length. What about posture balance mediated by the cerebellum? The cerebellum controls the balance between the agonist and antagonist muscle contractions. Actually we can talk about the cerebellum's role in muscle contraction and movement for several more centuries before we have a clear idea what it actually does...

So! Can we change the length of our muscles? YES! But probably in a way that you never thought. The way to "stretch" a muscle to change its length is to IMMOBILZE the joint! Animal experimentation clearly demonstrates that when a muscle is immobilized in a chronically lengthened (or shorten) position, sacromere numbers within the muscle cell increase (or decrease) so that maximal force and optimal sacromere length are produced at the position of the immobilized joint.

I dont think our patients would like us casting their neck, arms and legs to lengthen the affected muscles. So... where does this leave us? A tight/short/painful muscle is actually a splinted muscle and needs to have the stretch reflex activated so it can loosen and have fresh oxygen to restart its metabolism and decrease the intensity, or remove all together, the pain spasm cycle.

Ok... I am ranted out and am looking forward to your opinions

Adamo