For me, nudity was always natural from days of skinny-dipping with my friends. Showers with sports teams were required. Many guys were reticent, but coach said, "If I don't see you in the shower, I know you haven't sweat enough. So, the next workout will be harder and your chances of getting off the bench will decrease."
I played basketball in high school and the wrestling season was at the same time. We had a classroom in the boy's locker room area that we used for team meetings, health class, and learning sport rules. The weigh-in scales for wrestling were in front of the room. Someone had the brilliant idea to put 7th period study hall in that classroom. The wrestlers walked in naked even with the room full of girls and boys in study hall. Now that was braver than I've ever got. And none of the wrestlers ask for the scales to be relocated.