Keeping a dog in the area of fall is something that many trainers struggle with, and not just beginners.
Many young dogs have a tendency to move far too quickly and overshoot or leave the area of fall repeatedly. The handler is then forced to handle the dog back into the area over and over again.
And it can all start to look messy and become inefficient.
I have never seen a better demonstration of how to keep your gundog in the area of fall, than this one by Dave Latham. It speaks for itself. It’s worth every one of the five minutes you spend watching it.