I do a little of both and it depends on the class and the participants. For the most part, with my small group classes and circuit style classes, I perform the warm up with them and demonstrate the movements. Then I’ll move through the class, watching and coaching on form and keeping time. I’ll jump in if I feel the motivation of the class or various participants is dropping. If we’re doing partner work, I’ve been known to join in and partner up. Same with any competition style work we may do. Its great motivation for clients to gain up and “get” the trainer!