A race car typically has two master brake cylinders. One controls the front brakes and the other the rear. A dial between the two controls how much pressure goes to each.
This allows the driver to change the balance of the brakes. If the front tires are locking up too easily, you can move the balance to the rear somewhat to help.
Locking up the rears usually leads to a quick swapping of ends and the air being filled with expletives.
While a rearward bias will help you turn the car getting into the corner, too much will lead to bad things.