The Ottawa YWCA produced a number of fitness albums in the 1960s (so far, I've found two, and will post the second one soon). This one, called "Keep Fit With Dorothy Ball", features some great piano "musical accompaniment". It even has an accompanying booklet showing you all the positions you can be trying.

I'm not sure who Ms. Ball was, but she has a great voice, even if she does say "about" like a typical Canadian on South Park.

Side One Track Two