This concept is so important because it dictates what skills can be done after the round off.

If a back handspring or whip occurs after the round off the legs need to come together shortly after vertical so the body can snap down with feet in front of the body. If you don’t do this correctly the feet land in a duck like position which makes the handsprings high and not powerful.

If you want to go up out of the round off your legs will come together later so they arrive behind you. This makes you go up with a slight angle leaning forward. This gives you more height so you safely can complete the skill.

All of this depends of on the tightness of your body and proper positioning in a tight straight body.