Changes in northern hemisphere male international rugby union players' body mass and height between 1955 and 2015

Abstract

Objectives: We sought to establish the effects of professionalism, which officially began in 1995, on the body mass and height of northern hemisphere male international rugby union (RU) players. We hypothesised that mass would significantly increase following professionalism. We also investigated the changes in size of players according to their playing position, and we compared changes to rugby league (RL) players and the public.

Methods: The body mass and height of players representing their international team for that country's first game of the Five Nations in 1955, 1965, 1975, 1985 and 1995 and, for 2005 and 2015, the Six Nations, were collected from matchday programmes. RL players' data were collected from the Challenge Cup final games played in the same years.

Results: International RU player body mass has significantly increased since 1995. In 1955 mean (±SD) player body mass was 84.8 kg (±8.2); in 2015, it was 105.4 kg (±12.1), an increase of 24.3%. Between 1955 and 2015, the body mass of forwards increased steadily, whereas that of backs has mostly gone up since 1995. RU player body mass gain has exceeded that of RL, but the age-matched difference between RU players and the public has remained relatively constant.

Conclusions: The factors influencing the gain in body mass of rugby players are legion; however, we believe that the interpretation of the law relating to the scrum put-in and changes allowing substitutions have, at least in part, contributed to the observed changes. Injury severity is increasing, and this may be linked to greater forces (caused by greater body mass) occurring in contact. RU law makers should adjust the rules to encourage speed and skill at the expense of mass.

Keywords: body mass; professionalism; rugby union; weight.

Figure 1

Median, IQR and range of body mass international rugby union players taking part in the opening matches of the Five or Six Nations tournament in 1955, 1965, 1975, 1985, 1995, 2005 and 2015 (n=75 comprising 15 players representing England, Wales, Ireland, Scotland and France). Significance levels calculated by the Kruskal-Wallis test with Dunn’s post hoc analysis show p<0.01 (two icons); p<0.001 (three icons); p<0.0001 (four icons).

Figure 2

Mean body mass of international rugby union players taking part in the opening matches of the Five or Six nations tournament in 1955, 1965, 1975, 1985, 1995, 2005 and 2015 (n=15 at each time point comprising players representing England, Wales, Ireland, Scotland and France).

Figure 3

Mean and SD of body mass international rugby union players taking part in the opening matches of the Five or Six nations tournament in 1955, 1965, 1975, 1985, 1995, 2005 and 2015 divided according to whether they were forwards or backs (n=45 forwards and 40 backs representing England, Wales, Ireland, Scotland and France). Significance levels calculated by the Kruskal-Wallis test with Dunn’s post hoc analysis compared with 1955 show: a=p<0.01; b=p<0.001 and c=p<0.0001.

Figure 4

Mean and SD of body mass international rugby union (RU) players taking part in the opening matches of the Five or Six nations tournament, and rugby league (RL) players competing in the Challenge Cup final match in 1955, 1965, 1975, 1985, 1995, 2005 and 2015 (n=75 RU; n=26 RL, apart from 1955 where n=23 and 1995 when n=20). *p<0.05 by two-way analysis of variance.