There are a wide variety stretching procedures and it can be confusing to figure out which is the most effective. Some practitioners advocate a short duration stretch (about 2-3 seconds) as used in the Mattes method of Active Isolated Stretching (AIS). Others advocate a long duration of static stretching (15-20 seconds or more), as in practices such as yoga.
The research literature has studied stretching extensively but there is no conclusive evidence for a best stretching method yet. It appears that certain stretching methods work better in one situation while others work better in another. As I was doing some research on stretching recently it occurred to me that there are some additional factors in stretching that we may want to investigate.
In any stretching procedure there are two primary components that need to be addressed to effectively encourage muscle elongation. The first is a neurological component that governs the muscle’s resistance to stretch. It is here that the proprioceptors play a major role in stretching techniques. Techniques such as PNF or other facilitated stretching methods have been developed to focus on the neurological components of stretching.
Another factor in stretching is the mechanical elasticity of connective tissue (fascia) that surrounds muscles and bundles of muscle fibers. This connective tissue has a resistance to tensile (stretching) forces when those forces are rapidly applied. As you hold tensile force on this connective tissue, its resistance to stretching decreases. The decreasing resistance to stretch tension in connective tissue is a property called creep. Maximizing the effectiveness of connective tissue creep is an argument for a longer held stretch.
Recent research into the physiological properties of fascia have shown that it contains contractile cells. It has also been determined that a prolonged tensile force on connective tissue, such as that used in myofascial release or other fascial techniques, can cause a reduction in contractile activity in these fascial cells.
We now know that connective tissue elongation is enhanced by manual therapy methods of stretching fascia. We also know that connective tissue stretch (resistance to creep) is a limiting factor in stretching methods. What if we were to combine the two and encourage use of these myofascial techniques on muscles as they were in their fully stretched position? I’m sure some practitioners must be doing this already, so it would be interesting to see some comparative studies performed on this method.
