There are two types of stretching, static
Static stretching is the stuff like yoga
you hold a stretching position for a period of time and relax, then
do it again.
Its purpose is the lengthen your muscles and
you a freer and greater range of movement.
Dynamic stretching implies movement. These
exercises like high kicks and high knee lift running drills.
They are done to help warm up your
muscles and to loosen
up. As you are only moving slightly beyond your normal range of
movement and you are in a dynamic state, you are not likely to
overstretch and do serious damage.
Much of the discussion I have read about the
effects of stretching has partly been caused by confusing the two
types and when to do them.
When I was young, we warmed up by doing
stretching followed by dynamic stretching exercises.
Now it seems that research has shown that
stretching exercises reduce your performance at maximum effort.
In summary, if you are running 100m races,
or need fast
accelerations for short distances, static stretching beforehand may
well reduce your performance slightly.
For those of us who go out for a few miles
to keep fit,
it is not a problem.
But, if you want to do it properly, you
should only do
dynamic stretching before you run; swinging your legs and arms,
striders and drills, and save the static stretching for afterwards
when it palys a role in helping you to cool down after your run.
I was warned, when younger, that doing
weight training was a bad idea because the exercises weaken your
muscles and so there is a danger of over-stretching.
I have read recently that static stretching
training, especially using a partner, is useful to lengthen your
muscles resulting in fewer injuries from over-stretching during your
This seems somewhat contradictory.
You need to carefully balance the two;
dynamic stretching before you go out to get you warmed up, static
after training to lengthen your shortening muscles (see shin splints
article), but do it with care so you do not over-stretch.