L-Sits

L-Sits are a good static hold for developing core strength. You also use your shoulders and arms a great deal too. When you first perform this exercise you will suffer from the horrible cramping of your hip flexor muscles (tops of the thighs) as they work to keep your legs in the air! Take things slowly at first and build up the time gradually and your legs will get used to it and the cramping will soon disappear. Most people find they need to have their hands on a raised object to start with in order to get enough clearance from the floor.

1) Grip the press up bars or place your hands on raised objects.
2) With your legs straight out in front of you, push down with your hands and raise your bum up off the floor.
3) Try to keep your legs straight and at 90 degrees to your body.
4) Keep breathing normally.

A few things can be done to start this exercise off a little easier. Try doing it with your legs hanging off of a step. This means when they are out in front of you they can be less than horizontal, not hit the floor and you will still be working. Secondly, try doing it with only one leg straight. Keep the other leg bent up towards your body. This makes it easier as there is less weight to hold up. Remember to keep the time even on both sides if you do it this way.
Time how long you can hold it for, repeat for two or three sets with rest in between and gradually build up your time and strength.