This article is from the Stretching FAQ, by Brad Appleton Brad_Appleton@ivhs.mot.com with numerous contributions by others.
Once you have performed your static stretches, you should engage in some
light dynamic stretching: leg-raises, and arm-swings in all directions (See
"3.2 - Dynamic Stretching"). According to Kurz, you should do "as many sets
as it takes to reach your maximum range of motion in any given direction",
but do not work your muscles to the point of fatigue. Remember - this is
just a warm-up, the real workout comes later.
Some people are surprised to find that dynamic stretching has a place in
the warm-up. But think about it: you are "warming up" for a workout that is
(usually) going to involve a lot of dynamic activity. It makes sense that
you should perform some dynamic exercises to increase your dynamic
flexibility.
 
Continue to: