Sport Psychological Skill Levels and Related Psychosocial Factors That Distinguish Between Rugby Union Players of Different Participation Levels. Introduction The International Rugby Board repealed the rules on amateurism after the 1995 Rugby World Cup and as a result rugby became a professional sport (Treasure et al., 2000). Shortly after the 1995 World Cup tournament, Cox and Yoo (1995) stated that success in professional sport is not only dependent on the physical and tactical aspects but that psychological skills also need to be addressed. As a result, Garraway et al. (2000) pointed out that similar demands were placed on the rugby players' psychological skill levels, as has been the case in other professional sporting codes. Le Roux and Pienaar (2001) as well as Lyons (2001) further noted that sport psychology plays an important and ever-increasing role in the world of competitive sport. The importance of sport psychology is emphasized by the contention that the knowledge obtained by the study of an athletes' behaviour within a sporting environment could be used to explain, predict and change behaviour (Potgieter, 2003). The identification and development of sport psychological skills have subsequently become of great interest to players, coaches, administrators and sport psychology researchers, due to the relationship that exists between these skills and the development as well as performance of the modern rugby player (Golby & Sheard, 2004).