Abs of something

So this morning at the gym I took an abs/core 30 minute class. Before that I worked on the elliptical for 30 minutes. That abs/core class was killer. I will definitely be taking it again.
I liked the teacher–she told us, do what you can, rest, and do more. She never made me or anyone push harder than we should. We worked a lot with the balls. I am not the most graceful or balanced person–so I was giggling a few times.