Decompress .zlib files from "Mario & Sonic at the Sochi 2014 Olympic Winter Games"?

[TM67]

I found out that most of the models in Mario & Sonic at the Sochi 2014 Olympic Winter Games are compressed in .zlib format (from what I saw when looking into one of the compressed files in an hex editor). I have tried several programs like "zlibc","xpert2" or "offzip" but all of them give me errors. So, does anyone know a way to decompress this type of compression files? Thanks in advance