I recently was diagnosed with Ankylosing Spondylitis, a form of inflammatory arthritis in the SI joints, and when I went to a physico therapist they commend oh how I was hyper mobile in my joints. I've always been more flexible than other people, even cheer leaders are shocked at times that I practically never do gymnastics because I could do things they couldn't. I can clasp my hand together at the front and without letting go move then all the way around my head so they are against my back, think sort of like a skip rope or something. I have yet to find someone to tell why I'm able to do this with my shoulders, it's not painful, though I can get a weird popping noise as I do it.
I'm also able to do many other things that most 'normal' people can't, at least not without practice (like bend over and have my hands flat on the floor, arcing by back into that bridge like structure, having fingers that are double jointed, etc., mostly strange things involving my legs and arms), I was wondering if this is really classified as hyper mobility, as what I've seen here seems to be much more severe. Also, if it is, will it ever cause me problems in the future? I've never thought much of it until the therapist gave my flexibility a name and I decided to look it up, coming to this board.