You've all seen "the arch" where a lifter attempts to contort themselves in to the most mechanical advantageous position possible.
The first question is, should everyone do this? Well no of course not. But if you're competing in Powerlifting or want to press heavy weight then finding an optimal position makes sense.
We refer to this as GLOBAL EXTENSION where the lifter positions themselves in extreme extension - spine extended (from thoracic to lumbar) coupled with anterior pelvic tilt. This helps create tension through the body and provides leverage advantage over the weight on the bar.
To create a nice stable base of support, the scapula (shoulder blades) are retracted and depressed. This helps support the pressing movement by allowing an efficient transfer of force back through to the bar.
The roll of the legs and feet are important as well whereby we aim to have the feet back as far as possible which helps drop the knee and improve the extension we are creating. Now whether you are flat footed or on the toes, the principle is the same - get them back as far as possible. If you are on your toes be sure to maintain the ball of the feet in contact with the floor then driving the heels down to the floor to help tension up the body.
Global extension and your ability to improve the position will play a big roll in your success in the bench press so make sure you spend time on it!
Now we're all different and while the principles are the same, the application can vary slightly from person to person. If you want some help with this then reach out.