The objective of the study was to describe the morpho-structural characteristics according to playing position, in rugby players from the region of Valparaíso, Chile. Height, weight, body mass index (BMI) and other 25 anthropometric parameters were obtained from 121 competitive rugby players (24.2 ± 4.9 years), following the recommendations of the International Society for the advancement of Kinanthropometry. The body composition was described in 5 components through the method proposed by Kerr, they are muscle, fat, residual, bone and skin. The somatotype described by Carter and Heath, allowed to describe the components of endomorphy, mesomorphy and ectomorphy. To compare the morphostructural characteristics of the rugby players by playing position, these were separated into forwards and backs. Body weight, sitting and standing height, BMI and S 8-fold were higher in the forwards than the backs (p <0.0001). In relation to body mass, adipose tissue and absolute muscle were higher in the forwards than in the backs (P <0.01), but not in the relative. The somatotype showed significant differences in the averages of the three components between forwards 4.8-6.9-0.7 (1.8-1.3-0.8) and backs 3.7-6.1-1, 2 (1.8-1.1-0.8) with P <0.01. In conclusion, the playing position in rugby is decisive in the definition of basic physical and morphological characteristics. A higher body weight of the forwards versus backs is influenced by a greater muscle and adipose tissues. Latter was related to a greater mesomorphic and endomorphic component of the somatotype, and lower ectomorphic in the forwards. Despite these differences, both groups are classified as endo-mesomorph.

KEY WORDS: Rugby; Anthropometry; Somatotype; Body composition.