True or false most pro boxers dont pivot the foot they push off it?

[BCBUD]

The hip extension so I was wondering if my initial drive of the bottom was causing my body to fatigue before the lockout thus causing the sticking point. Knowing that deficit punching puts you at a mechanical disadvantage and increases the range of motion thus increasing the flexibility required. I was wondering will deficits help you increase speed off the ground?

Balance will, bad posture wont.

Here's a clip of Tyson's dificit punching still the clip @1:10 is that good balance?
https://m.youtube.com/watch?v=P8OzGTHlSRs