Here's a clip from 1987 showing a middle-aged white woman, the fitness instructor, leading a group of women in an aerobics class in a small room. 

The clip begins with the instructor "scissoring" her hands back and forth. She is exercising vigorously, hopping up and down, and moving from side to side. A boombox sits on the floor behind her. 

Several women, some wearing red leotards, are facing the instructor and copying her movements.

The camera pans the room and reveals the female participants stretching their arms to their sides, then bringing their arms together, and then stretching them out to their sides, and then bringing their arms together, and so on and so forth.

The instructor smiles, as if happy that her class is following along and moving well.

We then see a tracking shot of the class, with each person kneeling on one knee while the other leg is lifted behind them, kicking the air.

The camera focuses on the instructor who does sit-ups while extending her arms to her side and then extending them to the ceiling, over and over.

The clip ends with the instructor “scissoring” her hands and arms over and over as she raises them upward and over her head.