There are different type of stretching. Pre fight dynamic stretching is a good habit to get in to, and contrary to poular belief, static stretching also has a place in certain situations. It is a commonly known fact that pre training/fight static stretching can reduce muscular performance, however, this only applies where the duration is 30 seconds or more, with a view to increasing static flexibility. Short duration (10 seconds or less) pnf stretching will not harm performance, and depending on the individual, and the specific circumstances, could be included in a pre fight routine. Personally, when I was fighting, and when my fighters are warming up, I like to start of with some joint rotations, light skipping, dynamic stretching and a brief, dynamic yoga session. From there, we do shadowboxing, and a light pad session. If I find my fighters are getting tense, physically or mentally, we do some more yoga - I like my fighters to be calm and composed going into the ring. We also keep a close eye on nutririon for sevaral hours in the lead up to the fight, we rely heavily on liquids with a 2:1 carb/protein ratio. All in all, I like to spend about 2 hours on the pre fight routine.
Yeah cheers, it really captures that grittiness and honesty of boxing. Not to mention it's a future champ in Matvey Korobov!
That is a question you should ask a real athletic coach, not some fool in an internet forum. Stretching is a necessity.
Not when you need to use your energy straight afterwards. It's simple science, you can read about it anywhere grandpa.