Doctoral Degrees (Exercise, Sport and Lifestyle Medicine)
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Browsing Doctoral Degrees (Exercise, Sport and Lifestyle Medicine) by browse.metadata.advisor "Coetzee, Frederik"
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- ItemThe effect of law changes on the match profile of international and national rugby union between 2007 and 2013(Stellenbosch : Stellenbosch University, 2015-12) Kraak, Wilbur Julio; Venter, Ranel; Coetzee, Frederik; Stellenbosch University. Faculty of Education. Dept. of Sport Science.ENGLISH ABSTRACT: Rugby union has changed continually since the inception of professionalism in 1995. For example, to increase the appeal, continuity and safety of the game several law changes were introduced after the 2007 Rugby World Cup. The primary aim of this study was to determine the impact of these law changes on selected performance indicators on the match profile of international rugby union between 2007 and 2013 and national rugby union between 2008 and 2013. To this end, three specific objectives were set. The first was to compare the scoring profile of international rugby between 2007 and 2013. The second was to compare the changes in the general match profile of international rugby and the third was to compare the scoring and general match profile of Super Rugby between 2008 and 2013. The study followed a mixed-method study design for data collection. A total of 248 international and 646 national matches were recorded by the Fika Coding Centre and analyzed by the researcher using the Fairplay video analysis software package. Semi-structured interviews were conducted with 30 international- and national-level coaches, referees, specialist coaches and players.The year 2007 was used as baseline for international matches and 2008 for national matches in order to compare and track the changes over the different years. Results indicate that law changes over the years have indeed had an influence on the profile of international and national rugby. The scoring profile of international rugby revealed a significant increase in the number of penalty kicks (p<0.01). With regard to the origin of tries, there was a decrease in the number of tries from structured play (47 to 43%) and an increase from turnover possession (27 to 43%). The duration of the international matches increased owing to the increase in the number of stoppages, mainly as a result of greater use being made of the Television Match Official (TMO), substitutions and on-field concussion tests. There was a small practical significant increase in total match time (d=0.34), and a moderate increase in ball-in-play time (d=0.87). Results of the study show that the profile of international rugby has changed to a more continuous game dynamic with a moderate practical significant increase in the number of passes (d=0.73), large ball carries (d=1.22) and tackle breaks (d=2.03), and a very large increase in line breaks (d=3.00), which has led to a moderate increase in the number of tackles (d=0.65). The number of rucks (d=0.86), mauls (d=0.90) and scrums (d=1.03), scrum resets (d=0.74) and line-outs (d=0.61) showed a moderate practical significant decrease. Both penalty kicks (d=0.98) and free kicks (d=1.22) decreased significantly. The scoring profile of national rugby indicated fewer tries (p<0.01), conversion kicks (p<0.01) and significantly more penalty kicks (p<0.01). The duration of national matches decreased due to fewer stoppages, mainly thanks to the improved skill level of the players. There was a small practical significant decrease in total match time (d=0.41). The ball-in-play time (d=0.91) showed a moderate practical significant decrease. Results of the study show that the profile of national rugby has changed to a game with more contact situations, with a small practical significant increase in the number of passes (d=0.43), a large practical significant increase in the number of ball carries (d=1.34), tackle breaks (d=1.59) and line breaks (d=2.40), and has led to a moderate practical significant increase in the number of tackles (d=0.63). A large practical significant decrease in the number of rucks (d=1.73) and scrum resets (d=1.36) was found. A moderate practical significant increase in penalty kicks (d=2.04) and a moderate practical significant decrease in free kicks (d=4.53) between 2008 and 2013 were observed. By analyzing the scoring and match profile of international and national rugby, coaches and trainers could be better informed in order to develop training programmes that are specific to the technical, tactical and physical demands of modern rugby. Based on the findings of this study, coaches and trainers should develop individual and team performance profiles to better understand the demands experienced by the players and teams. This type of information could assist with implementing more specific periodization models, strategic planning, drill design, recovery strategies and planning of training loads.