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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A scientific analysis of running lines in rugby

Evert, Ashley 13 February 2004 (has links)
The game of rugby has been played for over a century and yet its intricacies are still not fully understood. The key ingredient coaches are seeking is what can be added to a team’s make-up that will result in an increase in that teams level of playing success. The objective of this study is the exploration of the biomechanical aspects of movement in a rugby context specifically looking at the stages before, during and after contact. The hypothesis is that the optimal use of running lines in rugby union will lead to more successful breaches in the opposition’s defensive lines thus an increase in linebreaks will occur. In order to make a comparison based on scientific research principles, nine matches played during the 2001 season was compared with nine matches played during the 2002 season. For each match played in the 2001 and 2002 seasons the total number of linebreaks achieved in a match was calculated. In addition the total number of linebreaks achieved in the 2002 season was further subdivided into the specific categories of intervention in order to determine which intervention had the biggest impact on the total number of linebreaks achieved. By means of video footage of the matches played notational analysis was performed and information was gathered in order to gain data for further evaluation. The actions regarding the execution of the linebreaks were evaluated manually in respect of the intervention that was imposed during the coaching of the team during the 2002 season. Without exception a comparison between similar teams played during both seasons indicated that the total number of linebreaks achieved during the 2002 season was much higher than when the team competed against similar opposition during the 2001 season. The aggregate numbers indicated a significant increase in linebreaks from the 2001 to 2002 season. This conclusion was achieved by means of a simple T-test. Firstly an applied F-test test was done to determine whether the two samples had equal variances or not. Under the null hypothesis we assume that the variances of the two samples are equal, while the alternative states that the two samples have different variances. A value for the test statistic that is greater than the critical value will lead to a rejection of the null hypothesis. The test statistic was calculated and evaluated against the F (8,8) = 2.59 critical value on a 5% level of significance. The value of 15.921 is greater than the critical value of 2.95 and therefore the null hypothesis cannot be accepted, concluding that the two samples do not have equal variances. We then proceeded to test whether the 2002 average linebreaks are significantly higher than the average linebreaks achieved in the 2001 season. Under the null hypothesis the two sample averages are equal. Under the alternative, the 2002 average is higher than the 2001 average. In contrast to normal T-tests this specific test was a one-sided upper or right hand test due to the fact that we are testing whether the one average is greater and not equal to the other. Therefore, we would only reject the null hypothesis of equal sample averages if the test statistic were greater than the appropriate critical value. The calculated test statistic is 4.4827 and was evaluated against the t 0.05,9 = 1.833 critical value. Once again we cannot accept the null hypothesis. Therefore we can conclude that the average of the total linebreaks made during the 2002 season is statistically greater than the average of the total linebreaks made during the 2001 season. The results of this study therefore indicate that the new techniques incorporated into the coaching of the team in 2002 did positively influence the number of linebreaks when compared to the 2001 season. / Dissertation (MA (Human Movement Science))--University of Pretoria, 2005. / Biokinetics, Sport and Leisure Sciences / unrestricted
2

The significance of dominant ball carrying collisions as an indicator of success in rugby union and the biomechanical analysis thereof

Evert, Ashley 13 December 2006 (has links)
The goal of this study is to gain a better understanding of the factors that play a role in dominant collisions in rugby as well as the relative significance of dominant collisions as an indicator of success. By means of video footage of matches played during the 2003-2005 Super 12 competitions, notational analysis was performed and information was gathered in order to gain the relative data. The hypothesis stands that if a team is aware of the factors that lead to a dominant collision, are able to execute them in a match situation, that team should be more successful. The following key performance measurements were evaluated in order to indicate how each factor affected the level of success of a team. They are as follows: average total number of collisions for a try to be scored, average total number of forced missed tackles for a try to be scored, ratio of dominant collisions versus passes executed when a try is scored and average positive velocity change of dominant collisions resulting in a try being scored. In order to prove the hypotheses a k-sample case will be used. The samples are related, thus the data used is interval and ratio. Therefore, the test used will be the repeated measures ANOVA test, a special form of n-way analysis of variance. The statistical evaluation is the critical test value where the d.f values are as following: Key Measurement (3,8), Year Rating (2,8), Year Rating by Key Measurement (3,8). When comparing these with a statistical table for critical values of the F distribution for Ą = 0.05, the critical values are as following: (3,8): 4.07, (2,8): 4.46, and (3,8): 4.07. Thus, the statistical results are grounds for accepting all three null hypotheses and concluding that there is a statistical significance of at least 95% with an alpha of 0.05 between the means in all three instances. This shows that the data captured for the twelve teams for all tries scored by these teams over a period of three years and for the four key measurements, have a statistical significance of 95% for the readings respectively. After evaluation of the data and making use of regression analysis and multiple regressions in order to establish the correlation between log position and the four key measurements there can be no doubt that the teams that finished higher on the log did indeed perform better according to the identified key performance measurements. / Thesis (DPhil (Human Movement Science))--University of Pretoria, 2006. / Biokinetics, Sport and Leisure Sciences / unrestricted

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