Contra is used in two contexts.
It is often used to teach walking. The contra walk is deprecated as it is often counterproductive. Similar to the term disassociation, contra is an instruction both imprecise and excessive. Arbitrary implementation of contra motion at the wrong point in the step weakens the body by causing internal rotation of the legs or yanking the shoulders away from the arch of connection.
Contra co-contractions (not deprecated) are those in which the partners move in different directions, as opposed to moving together. Contra co-contractions create sharp, sassy, quick power and whiplike effects. Some movements can be marked either pro- or contra- (rebote, voleo, gancho, piernazo). A few movements can only be done contra- (rebote cadera, patada).