Whether it’s splits or backbending, we want to avoid placing all of our bend between a few vertebrae.
If you want to improve your front split, focus on back leg hip extension while minimizing your lumbar extension. This means controlling your pelvis so that it doesn’t tip forward too much into anterior tilt and controlling your ribs so they don’t flare out too much.
A great drill to practice this principle is in the lunged deadlift.