Flexibility exercise is extremely important in pole fitness...warm ups that include deep stretching is essential when you will be moving your limbs and body in a wide range of movements during pole dancing.
Splits are a common pole trick that many dancers want to be able to do as it is an impressive motion to slide down the pole and land in front splits.
But it takes time and patience to stretch and develop the range of motion needed in your joints and tendons. There is an effective plan that anyone can try for being able to do the splits in as little as six weeks. This program should be used as it is incremental and you won't injure yourself by trying to split too quickly. This also explains why you CAN do the splits even if you feel that you will be unable to.
There is also a classic book that illustrates stretches that have been used by many athletes Stretching by Bob Anderson or one of my favorite stretching books Stretching Anatomy.