What is a hollow body? And what is the difference between just drawing in the belly?
Drawing in: Spine stays neutral, core engagement only moves belly towards the spine. We want to draw in our belly to activate the deep core muscles to stabilize the spine and create a solid base for the limbs to move. The lower and deep core often get too little attention. They play a significant role in functional movement and should be trained regularly and engaged through nearly all functional movements of any kind.
Hollowing: Pelvis tucked, core engaged & drawing in --> there is a change in the spine.
On the other hand, the hollow body describes a particular body form that we want to achieve for a specific movement. It creates a solid base for functional movements and *includes* drawing in and additionally tucking the pelvis.
Here's a short demo video for you!