Term used to describe a fit woman who still has natural perky & full breasts. Originally the brand-name of an automobile attachment used to carry extreme sports accessories, it can be used as an adjective, noun or nickname. Often used as an endearing term or compliment to a special lady friend that is in good shape but has not lost her 'upper-deck'.
A true sport-rack should retain some of the qualities of it's genesis so that when 'equipment' is placed on the 'rack' it does not fall off.
I always date fitness instructors that have exercised their boobs into oblivion, would love to find a good Sport Rack someday.
My canoe keeps getting scuffed on the ground, I need a better sport rack.