Source: www.body-fizzeek.co.uk . . .Splits TrainingIn General:

Start by holding stretches for 20-30 seconds, and gradually increase to 60 seconds

Do not 'bounce' when stretching

Rather than holding a stretch for 2 minutes, hold it for 1 min, have a 30 second rest, then hold for another min. You often
find that you will be more flexible the second time around.
The best way to increase flexibility is through:
Static Stretching --> where a stretch is held at it's maximum for a length of time
PNF stretching --> where the stretch is held and at the same time resistance is offered so that the muscles have
to work in order to keep the stretch at it's maximum. This is more advanced then static stretching and is usually done in
partners with one partner stretching and the other offering resistance.

All exercises should be performed correctly, i.e.: in splits the hips should not twist
Forwards Splits--Preparation Exercises
Kneeling Lunge:

Hips square

Body upright

Hands on floor either side of front leg

Back knee forced squarely on the floor
Lunge with back leg against a wall/box
Keep hips square

Push hips to ground

Keep shoulders square and tall

Keep body upright.
Pike sit reaching forward
Keep legs straight

Keep hips on Floor

Lean forward with a flat back

Try to reach over toes
Single leg stretch on back
Keep hips square

Keep hips on floor

Use own force to stretch

Leg not being stretched should be bent
Hip Stretch on a box
Keep hips square

Pull bent leg to chest whist maintaining force on the straight leg
Splits:

Shoulders square

Keep hips Square

Front leg facing the ceiling, back leg facing the floor

Support hands to be even and behind hips
Forward Splits--Hints
and Tips
If you are able to perform splits, sitting in splits will maintain your ability to do them, but will not improve flexibility
any further

In order to increase flexibility, over splits should be performed with one leg on a height. This height should increase gradually
as flexibility improves. Ideas for a height include: a stack of books, a chair, a stack of pillows, a box, a beam/wedge/shape
or anything lying around the gym

In order to increase flexibility, you should stretch every day and if possible, twice a day. Wake up 10 minutes earlier than
usual for gentle stretching in the morning, this will then make it easier to stretch later in the day.

Remember that quality is important. A good technique should always be used. If you practice splits with feet flexed and back
leg bent, then you are also likely to repeat these errors in other skill such as split leaps and balances.

I have found that the fastest and most efficient way to get down in splits is to do them on the floor, with two chairs at
either side at your arms. Hold on to the chairs (whilst in splits) and push with your legs against the ground for 10 seconds,
then relax, slide down a little further and repeat. This is a version of PNF stretching and is very successful if you are
almost down in splits but not quite. It is also very good to use on your 'bad' leg.
Side Splits - Preparation Exercises
Frog position on stomach (baby splits) 
Keep hips square

Keep knees in line with hips

Keep body flat on floor
Straddles sit 
Knees facing ceiling

Lean body forward with a straight back

Knees and feet should be fully extended
Side Splits - Hints
and Tips 
The ideal position for side splits (in my own opinion) is with knees facing the ceiling and legs hyperextend (so that the
knee pushes into the ground and the heal of the foot is slightly off the ground). These splits can only be achieved if you
are past splits with your knees facing forwards.

The first step for side splits is with knees facing forwards and elbows on the ground, rather than straight arms. It is harder
to 'cheat' this way and is safer for your back.

The second step is over splits (i.e. with one leg raised)