At all times, the axes of rotation of the handholds are parallel to each other and extend along a plane that contains the axis of {HEAD ~ circumduction} of {TAIL ~ the users shoulders} 
of
At all times , the axes of rotation of the handholds are parallel to each other and extend along a plane that contains the axis of { HEAD ~ circumduction } of { TAIL ~ the users shoulders }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL