RT Journal Article SR Electronic T1 Year Book of Rehabilitation 1986 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 142 OP 142 DO 10.1136/bjsm.21.3.142-a VO 21 IS 3 A1 John G. P. Williams YR 1987 UL http://bjsm.bmj.com/content/21/3/142.2.abstract AB