Most of these films have been quickies on the order of ''Don't Knock the Rock'' (1957) and ''Twist Around the Clock'' (1962), but there have occasionally been more ambitious if not much better films (Herbert Ross's ''Footloose,'' 1984).
Taking a formula that is itself creaky of joint and infirm of body, Eleanor Bergstein, the writer, and Emile Ardolino, the director, have made an engaging pop-movie romance of somewhat more substance than one usually finds in summer movies designed for the young.
I suspect that one's responses to ''Dirty Dancing,'' to its period details, even to its state of mind, will depend on the associations one brings into the theater.
What is undeniable, however, is a basic decency of feeling, shaped, in part, by the film's obligations to its optimistic genre.
President Kennedy was still alive, America's stake in Vietnam had not yet become divisive, and socially conscious young people were going on freedom marches in the South and joining the Peace Corps.
The film is about Frances Houseman (Jennifer Grey), nicknamed Baby, a pretty middle-class teen-ager who finds her adult identity in her first love affair - with Johnny Castle (Patrick Swayze), the hotel's dance instructor.
For a girl of Baby's conventionally liberal, Jewish background (she's planning to study ''third world economics'' in college), Johnny, a young man from the wrong side of the tracks, exemplifies the freedom expressed through a new and as yet socially unacceptable form of dancing.This ''dirty dancing,'' a phrase used only in the film's title, features a lot of steamy body contact and pelvic thrusts, which unleash emotions supposedly left withered by mambos and cha-cha-chas.LEAD: IN their time, almost all forms of popular American music and dancing, from the foxtrot and the tango through rock-and-roll and all of its variations, have scandalized the members of an older generation, whose own sexuality had earlier been liberated by tamer means.As music, lyrics and dance steps have become more and more sexually explicit, fathers and mothers from coast to coast have felt alienated, and worried that pop music was leading their children straight to hell.IN their time, almost all forms of popular American music and dancing, from the foxtrot and the tango through rock-and-roll and all of its variations, have scandalized the members of an older generation, whose own sexuality had earlier been liberated by tamer means.As it was with the bunny hug, danced to a ragtime tune in 1910, so is it today when Madonna sings ''Papa Don't Preach.'' This culture generation gap has produced its own Hollywood genre.