A pelvis interface may include a subject attachment module including a waist attachment and a back attachment. The interface may further include an arm assembly coupled to the subject attachment module, the arm assembly including a plurality of arms so coupled to one another and/or to the subject attachment module as to permit the subject attachment module at least one pelvis translation degree of freedom and at least one pelvis rotation degree of freedom. The interface may further include motors so coupled to the arm assembly as to actuate at least one pelvis translation degree of freedom and at least one pelvis rotation degree of freedom.