Die ewolusie van springbok rugbyspelers se liggaamsgrootte : 1896-2004

Abstract

The aim of this study was firstly, to investigate the percentage increase in the body size of the Springbok rugby players over a period of 108 years and to compare this increase with that of the general population. Secondly, it aimed at comparing the data of this study with existing data of international rugby players in other countries. Data concerning 1349 rugby players that formed part of the Springboks between 1896 and 2004 was collected in order to study the changes in body size of these players. Of the 1349 players, 664 were forwards and 685 backs. To be able to compare the data of the other international rugby players, the entire period was divided into two groups, namely 1896-1970 and 1971-2004. The anthropometric variables only included body length, body mass and body mass index (BMI) because in most cases, these were the only variables that had been measured. The results were as follows: the total group registered a mass increase of 2.03 (1.8-2.2)kg per decade and the increase in length per decade for the total group was 0.84 (0.75-0.92)cm . As expected, the BMI had increased by 0.31 (0.27-0.34)kg/m-2 per decade. The mass increase of the forwards and backs was 2.47 (2.32-2.61)kg per decade and 1.45 (1.32-1.57)kg per decade respectively. The length of the forwards and backs had increased as follows: 0.94 (0.83-1.04)cm per decade and 0.69 (0.59-0.78)cm per decade respectively with the BMI of the forwards and backs that had increased by 0.38 (0.33-1.43)kg/m-2 and 0.21 (0.18 - 0.26) kg/m-2 per decade respectively. The 95% confidence intervals for the increases with the total group for body mass, body length and BMI all indicate that the increases for the period 1976-2004 are statistically larger than the increases for the period 1896-2004 (r>0.25)The increases with the forwards and back for the period 1976-2004 were also significantly larger (r>0.25)than those of the general population. Compared to the other studies done on international rugby players, it was found that the increase in length with the All Blacks and the Wallabies, namely 1.1-2.1 cm per decade was larger than in the case of the Springboks, namely 0.84 cm per decade. The mass increase of (2.1-3.1)kg per decade and BMI increase of (0.3-0.4)kg/m-2 was comparable to the increases in mass (1.8-2.2)kg per decade and BMI (0.3-0.4)kg/m-2 that was found with the Springbok rugby players. For team selection and game development, knowledge regarding the change in body size and -form is becoming increasingly important to the trainers, managers and selectors of the teams.