In  this  preview  talk,  I  will  present  a  short  summary  of  our  ongoing  work  related  to  human shoulder functional kinematics.  Robot-assisted rehabilitation needs functional understanding of human kinematics in design, operation and evaluation of this technology. Human shoulder is an important  functional  joint  that  enables  fine  motor  skills  for  human  upper  arm  manipulation. Due  to  several  mathematical  and  practical  challenges,  the  shoulder  kinematics  is  often oversimplified. Moreover, there is a lack of agreement among different research communities on  the  suitable  kinematic  representation  when  connecting  humans  to  robots.  Currently,  it  is expected  that  this  computational  structure  used  in  such  applications  have  high-reliability. Therefore,  we  pose  the  question:  Are  we  ready  for  the  high-reliability  computational challenge?