Hello I've done a bit of research and found out cat (character animation toolkit in 3ds max) rigs are capable of squash and stretch or at least they were, all the articles and tutorials (most broken) are from 2009/13ish and when turning on "manipulation causes stretching" as shown in tutorials, nothing happens the rig wont…
I found that tutorial but it wouldn't load at all, maybe it 's my browser (Chrome) and yup that was the problem, I didn't set the whole bone chain to manipulate. Thanks Hito