Well, it's hard to know what "course" is without context. But I'm guessing it's either a school course (i.e. taking a class) or a land course (i.e. driving on a road). It can't be a ship course because you don't generally get bumps on ships, you get waves. But all of these courses can be bumpy. The land ones in a literal sense, and the school ones in a figurative sense.