Where do these ideas come from?
You don’t need to ingest carbohydrates to get through a VO2max workout, and in fact it could be detrimental if you end up spilling your guts or even if you just cause blood flow to be diverted to your digestive tract.
Your pre-exercise intake also isn’t going to have any major effect provided your muscle glycogen stores are adequate to start (which will be mostly determined by what you did/ate the day before we although you could add a few minutes’ worth by “topping them up” with a high carb meal 4-6 hours out).