RT Journal Article SR Electronic T1 The effect of physical activity on the knee joint: is it good or bad? JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 546 OP 547 DO 10.1136/bjsm.2007.037416 VO 41 IS 9 A1 Urquhart, Donna M A1 Wluka, Anita E A1 Teichtahl, Andrew J A1 Cicuttini, Flavia M YR 2007 UL http://bjsm.bmj.com/content/41/9/546.abstract AB