cardio in between sets

dargytaylor

I have been doing the 30 minute circuit @ Planet Fitness.

For those that are unfamiliar with it:

They have 20 'stations'. 10 machines, 10 steps for cardio.

My question is this:

What can I do other than the following for the cardio? (I obviously don't always use the step )

Jumping Jacks
"mock" jump roping
High Knees
and of course stepping super fast on the step

Thanks!!