I'll explain the situation: I am working on a project which involves making people turn their heads from left to right repeatedly and recording their moves. Once this is done, I separate the data into several samples which are: starting left, going right and coming back left (there is a "checkpoint" every time people are at the left end of their moves).
I have trouble finding a way to describe this motion. In French, we'd call it "un aller-retour", but the usual translation is a "round trip" and it seems weird to use it in such a context. Am I wrong?
If not, is there an English word that describes a general motion which goes back and forth?