Why would she say "around the world?" What does it mean?

Native speaker’s answer
Rebecca
Good question! There are many exercises called "around the world," including the leg/knee exercise being demonstrated by the trainer and students in this video. It's described as being "around the world" because it requires you to perform a wide rotational action. There are many exercises or moves that are named in this metaphorical manner, both for humor and to better describe the action involved. Ex: Let's get started with some around the world leg exercises. Ex: Do two sets of around the worlds, then some jumping jacks.