The Hollow Body Hold is an awesome bodyweight ab exercise and an important position to master for other exercises as well, like: Hanging Leg Raises, Deadbugs, Reverse Crunches, Handstands and many other exercises.
It’s really challenging and simple to perform, unfortunately it’s often performed incorrectly.
Here’s how to do it:
Keep your lower back flat against the floor the entire time.
☝ Top Picture ❌ You can see daylight because my lower back is hyperextended — defeating the purpose of the exercise.