'n Morfologiese profiel van junior en senior Cravenweek rugbyspelers

Abstract

A MORPHOLOGICAL PROFILE OF JUNIOR AND SENIOR CRAVENWEEK RUGBY PLAYERS The purpose of this study was to desc1ibe and compare the morphology of elite South African schoolboy rugby players. A comparison between the players in the ten different playing positions was made to determine if the morphological differences identified in the literature for adult rugby players in the ten different playing positions also occurred among the rugby playing youth at both primary school and high school levels. A comparison was also made between the Cravenweek rugby players and adult rugby players to determine if there was a morphological likeness among the rugby playing youth, in the different playing positions, as well as a likeness with adult rugby players in the corresponding playing positions when they were compared by means of a technique such as somatotyping which compensates for the growth factor. The study also indicated whether the morphological models that are used as a norm for adult rugby players could be implemented directly for the rugby playing youth. The schoolboys were taking part at provincial (regional) level in the 1989 Danie Craven rugbyweek for elite primary school (junior) and secondary school (senior) rugby players. A total number of 237 junior Cravenweek players (grades 6 and 7) with a mean age of 13.1 years and 369 senior Cravenweek players (grades 11 and 12) with a mean age of 18.1 years were measured. In compiling the morphological profile of the Cravenweek rugby players, a total of 34 anthropometric measurements were taken on each subject which included body mass, stature, heights, girths, breadths and skinfolds. An additional 9 transformations of the absolute size, as well as percentage body fat, lean body mass and somatotypes were computed. The comparison between the players in the different playing positions as well as between the junior Cravenweek, senior Cravenweek and adult rugby players were made by means of a one-way analysis

of variance, the Newman-Keuls follow-up test and the omega square test (w2 ). Somatotypes were determined by means of the Heath-Carter method. With regard to the differences between players in the different playing positions the results revealed that meaningful morphological differences occurred between both the junior and senior Cravenweek rugby players. This was similar to that found for adult rugby players. The omega square test (w2 ) indicated that, with a few exceptions, body build accounted for a significant proportion of the variance between the players in their l espective playing positions. Although significant differences occurred betweenplayers in the different playing positions, it must be emphasized that the extent of the differences, determined in a post-hoc manner by means of the Newman-Keuls test, differed for adult players and Cravenweek players. This trend also applied to the differences between the junior and senior Cravenweek players. The comparison between the Cravenweek rugby players and the adult rugby players indicated that the three age groups revealed a similar general body build with regard to the props, flankers, wings and fullbacks. With regard to the props the three groups of players did not differ significantly from each other in terms of their body fat ( endomorphy), while this trend did occur for hookers and flankers with regard to mesomorphy. No significant differences with regard to either endo- or mesomorphy were identified for wings and fullbacks. The significant differences that occurred throughout with regard to the ectomorphic component lead to the conclusion that the Cravenweek players had a body mass that was relatively higher in relationship to their stature in comparison to the other two groups. In some instances (locks, no. 8's and fly halfs) this trend also applied between senior Cravenweek players and adult players. The results therefore indicate that the differences between the junior Cravenweek, senior Cravenweek and adult rugby players in terms of the growth factor do not disappear completely when growth differences are compensated for. This leads to the conclusion that the morphological models applied to adult players cannot be directly implemented for the rugby playing youth.