Maybe they mean spinning while the trapeze is spinning too? I have never seen an actual head spin with a static trapeze, but it doesn't sound too impossible for me. Plenty of videos of spinning in a headstand on a rotating trapeze, it is a common trick in washington acts..
https://youtu.be/pOgavpr1Kfg?start=249
by Daniel Simu, in response to this post 2015-10-14 10:47:20