Two of his dogs swooped out of their kennels and met at the backs of my knees, and I went down without resistance, like some pug happy for a payday. (si.com)
Just have a pro-football player TAP the back of your knee. (sbnation.com)
«I had some scar tissue in (my ankle) from (competing) and that was kinda affecting my hamstrings and the backs of my knees. (sportstarsmag.com)