{HEAD ~ a pair} of handhold means having axes of rotation parallel to each other, each handhold means comprising an upper end pivotally mounted and detachably re positionable at {TAIL ~ a plurality} of selected locations along the length of the guide means; and 
{ HEAD ~ a pair } of handhold means having axes of rotation parallel to each other , each handhold means comprising an upper end pivotally mounted and detachably re positionable at { TAIL ~ a plurality } of selected locations along the length of the guide means ; and
HEAD HEAD HEAD HEAD HEAD HEAD 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 TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH