The latest Choice Health Reader refers to this paper:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3273886/
In short it is a review of the current concepts about muscle stretching for exercise and rehabilitation (as the title of the paper suggests!).
You need some basic terminology to start with, which I have copied from the Health Reader:
Static stretching….holding the muscle in a position of lengthening tension, maintained for a period of time and then releasing and repeating on the other side of the body.
Dynamic stretching….involves taking the limb through its full range of motion (swimmers swinging their arms before a swim
Pre-contraction stretching…..contracting the muscle prior to performing the stretch.
The summary in the Health Reader, of the paper, is:
“In many rehabilitation circumstances, sustained and regular static and PNF stretching increases joint mobility. Dynamic stretching is better suited for athletes, particularly those who run, jump, swim or throw. Increasing and maintaining joint flexibilty is essential in maintaining optimal movement as we age, so structured stretching is a good long-term strategy to maintain joint integrity and mobility”
I found this piece interesting as I did a lot of aerobics and running in the 1980s and 1990s when stretching was the way to go. You never started a class or a run without doing some stretching first. And then a warm up, your hard exercises or running, a cool down and final stretching. I understand more recently stretching has been given bad press and people are not doing it as much. My information is only anecdotal, and has n=1 (me) but I believe (note that word) that the reason I maintained quite good flexibility for years after I stopped all that stuff and wound it back to walking is to do with having stretched out properly during my most active years. I do feel now that I am in my fifties that I need to pick up my stretching routines again, which I have let lapse rather in the last three or four years.