DAREBEE Workout: What it Works
Training the abdominal muscle group is no easy task. The muscles do not all respond to training at the same rate and there is a core group of abdominal s, running beneath the external ones with muscle fibres pointing the opposite way. This makes for a core picture which no single exercise can adequately address which helps explain why strong abs are hard to attain, which makes them an aim to strive for.
Extra Credit: Keep the plank throughout, don't drop down.