The hollow-body rock is a bodyweight abdominal exercise performed on the floor. It starts with a hollow-body hold and adds a back-and-forth rock that challenges core stability and increases the difficulty of the movement. It can be performed for time or for reps, either in an ab-focused portion of a workout or as part of a circuit workout.
Simple way to progress hollow-body holds when you can perform them for a long time
Builds serious core strength and stability
More difficult and effective than long-duration planks