Tennis has been hard on Ellen Marin's knees. At 67, she's suffered through two torn anterior cruciate ligaments and meniscus tears in both her knees.
http://www.lohud.com/needlogin?type=login&redirecturl=http%3A%2F%2Fwww.lohud.com%2Fapps%2Fpbcs.dll%2Farticle%3FAID%3D2013309190112%26nclick_check%3D1
http://www.lohud.com/needlogin?type=login&redirecturl=http%3A%2F%2Fwww.lohud.com%2Fapps%2Fpbcs.dll%2Farticle%3FAID%3D2013309190112%26nclick_check%3D1