I only had one book from this series, and it involved a girl entering a figure skating competition and having some trouble with it, so she uses this chest that she and a handful of her friends have access to (presumably these friends were main characters of their own books in the series.) Somehow the chest transports her to the late 70s early 80s to a multinational figure skating thing where she's gotta learn from the other skaters. Her main competition is this intense brunette girl (maybe German?) and in the finale the brunette falls really badly, possibly injured, but she still gets a 6.0 from one of the judges and really high scores from all the others because of how brave she was to keep going with her routine after that fall.

I would have read this somewhere around the late 90s, 2000 at the latest. Format was very similar to the American Girl books, about 50 or so pages, maybe 6 chapters.

Any help would be greatly appreciated!