RT Journal Article SR Electronic T1 “The unfriendly games” 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 79 OP 79 DO 10.1136/bjsm.36.2.79 VO 36 IS 2 A1 P McCrory YR 2002 UL http://bjsm.bmj.com/content/36/2/79.1.abstract AB