I’ve taken apparatus classes at a few places in town. I went to Excel Movement for several years, including when I was recovering from knee surgery. I found all of their instructors to be knowledgable about anatomy, injuries and modifications. It’s up in Brookland walking distance from the CUA metro. I also found the staff at Pure Joe (13th and Mass) to be good on things like this. Both of these places teach the classic style, in case you care about things like that. I’d regularly go to both, but can’t justify the additional cost on top of my monthly gym membership.