These briefs can't be used in a competition unless multiply is allowed. They're not like a knee sleeve of compression. They're much thicker and restrictive. As with all gear, you have to learn how to use it properly or you get nothing. I only use my briefs instead of both briefs and suit as this is speed work and it would take too much time to hit depth in briefs and suit. A good pair of multiply briefs can give you 150-200# of carryover if they're appropriately fitted and used correctly. Same with bench shirts, but those can give even more carryover depending on the number of ply on the chest and sleeves.