Let’s talk for a moment about the physiology of stretching. The purpose of a stretching program is to relax a muscle and work it through its range of motion. Muscles should only be stretched after they have been warmed up. Flip side, one should not stretch just after a long or strenuous workout when your muscles are likely to be fatigued and dehydrated. Rehydrate and rest before stretching.
Stretching is done to relax the muscles and the connective tissue. To stretch effectively we have to overcome a natural safeguard that is built into our muscles to keep them from being damaged by overextending too quickly.
Muscles contain receptors called “spindles” and “Golgi tendon organs” that act together to protect our muscles. The main purpose of the spindles is to respond to stretch in a muscle and, through reflex action, initiate a stronger contraction to reduce this stretch. This pretty effectively limits how far you can quickly stretch a muscle: The spindles resist quick stretching of our muscles.
The Golgi tendon organs cause reflex relaxation of the muscle and its opposing muscle. If the stretch is held long enough, the Golgi tendon organs allow the muscle to relax. This lengthens the muscle and allows it to remain in a stretched position.
OK - so much for the physiology of spindle cells, Golgi tendon organs and the like.
We have all seen people stretching by twisting back and forth at the waist - swinging from one side to the other. Or by stretching and then bouncing against the limit of their stretch. This is called Ballistic Stretching. This kind of stretching actually make the muscles shorter and tighter by activating the stretch reflex and have been found to contribute to the risk of small muscle tears, soreness and injury. Let’s not do these.
What we want to focus on is a slow gradual stretch though the muscle's full range of motion until resistance is felt. This is called Static Stretching. The stretch should be done slowly and carefully to the point of slight pull or slight discomfort. It should not be painful.
Bottom line is that it takes time to stretch. I was taught in my Personal Trainer certification course that one needs to hold a stretch for 20 to 30 seconds to get muscles to relax. Some sources say that the Golgi tendon organ starts to let the muscle relax after only 6 seconds, but that one must continue to stretch for 20 seconds or longer to get a good stretch. Some sources say as long as 2 minutes.
Probably the easiest way to think of this is to try to stretch a little bit farther each time you take a breath while stretching. As adults we breathe between 12 and 20 times per minute if we are not exercising. When I am stretching I count my breaths, and typically hold a stretch for 10 to 15 exhalations, while seeing if I can stretch just a bit farther each time I exhale.
Stretching is not a competitive sport. Flexibility differs with each individual. Your goal should be to achieve a good level of flexibility for you, not to match anyone else's level. This was brought home to me last week when a lady joined our stretch session and gave us a few pointers. With 35 years of yoga behind her she is an exquisite example of the benefits of stretching. Believe me, I can only dream of being as flexible as she, but that doesn't keep me from doing my best to go just the least bit farther in each of my stretches.
The take home message from this posting: If you do a fairly complete stretching routine it can easily take 20 to 30 minutes. And leave you feeling so much better it is almost unbelievable. Oh, and reduce the risk that you will pull a muscle!
My next posting will discuss some of the stretches I do and why I feel they are important.
I used several references for the above, but pulled the most information from Team Oregon Stretching Reference