(1980s) Our PE teacher and football coach mentioned several times during PE class that jockstraps were required and he would be conducting jock checks - showing us he was wearing his by pulling out one of the leg straps.
His teacher assistants (usually members of the football team) would point...
A friend of mine in the military talked about wearing wearing his jock for exercising. When I saw it, it was a traditional Bike. Most everyone else would switch to white briefs for support in sports.