This talented young gymnast is making a nice effort to emphasize a chest hollow position at the beginning of the skill.  The objective of this action is to create a feeling about the shape of the body on the second flying phase.  Nowadays she still has some troubles to hold a hollow position on the turn over from hands to feet and pikes down instead.  Rounding the chest and back into a hollow position allows the gymnast to increase the power of the upper body motion when jumping up and backward to the backhandspring tight arch first flying phase.  It also mimics the way handsprings and sommersaults connect in between them.