This is called a over split you put your leg on something high and you push your waist down as far as you can go. You should start on something high and go up farther once you get it.
Have you ever wondered how to do a chin stand. In my opinion a chin stand is easy to do. If your in gymnastics, you should try this out one day. When you get it once it is easy to do after.
A needle is like a scorpion. They are a little alike but the scorpion your leg is bent the needle your leg is straight up. In my opinion a needle is a hard thing to learn, and the scorpion is easy thing to learn.
This split that she is doing is very hard to get high up in the air. If you are having trouble doing it on the balance beam my opinion is that you should rather do it on the floor then the beam because, when you land you have to make sure you land on the beam if you are doing it on the beam.