Department of Orthopaedics Somatotype Arthur Stewart Mandy Plumb Department of Orthopaedics

It is independent of size, age and gender. Somatotype Definition Somatotype is a physique classification system which recognises a body shape category, which necessarily falls between pre-determined end limits. It is defined as a quantified expression and description of the present morphological conformation of a person. It is independent of size, age and gender.

Somatotype Somatotype is a three figure reference which characterises physique and body shape. It comprises values, originally proposed on a 7-point scale, which summarise the physique, and can be plotted on the tri-polar somatochart.

Somatotype Components Average value Endomorphy Mesomorphy Ectomorphy 2 3 4 5 6 lean fat slender muscular heavy light

Somatotype History Originally proposed as a genotypic morphology rating on a 7 point scale by Sheldon (1940), drawing from earlier work of Kretschmer (1921) who classified three ‘poles’ to represent extreme physique variation, and Viola (1933) which related dimensions of the thorax, trunk and limbs to a ‘normotype’ Partly influenced by an alternative methodology from Parnell (1954), Heath and Carter (1967) introduced a three numeral rating somatotype which has become the most universally applied, which involved a photoscopic and anthropometric method, later to be revised in 1990.

Somatotype Assessment Methods *Equipment required Photoscopic Anthropometric* somatotype rating form computer-calculated Combined the criterion measure Stadiometer Weighing scale Bone caliper Skin caliper Anthropometric tape

Somatotype Rating Form

Somatochart Central Endomorph Mesomorph Ectomorph

Anthropometric Somatotype Assessment (Heath & Carter, 1967) Endomorphy Roundness or fatness, based on 3 skinfolds Independent of size Mesomorphy Musculo-skeletal robustness, based on elbow & knee breadths, and corrected girths of calf and upper arm Ectomorphy Relative fragility, based on height and weight Derived on 10 measurements Independent of size Descriptor of shape Assumes proportionality of size, development and symmetry Only relative data on composition

Measurements Required Total mass (kg) Stature (cm) Upper arm circumference (cm) Max. Calf circumference (cm) Femur breadth (cm) Humerus breadth (cm) Triceps skinfold (mm) Subscapular skinfold (mm) Supraspinale skinfold (mm) Medial calf skinfold (mm) Measurements on the Right; Larger girths in the case of Left handed subjects; mean of 2 or median of 3.

Endomorphy calculation Add the skinfolds at the triceps, subscapular and supraspinale sites Multiply this sum by 170.18 / height This total (in mm) is “X” in the following calculation: Endomorphy = -0.7182 + 0.145X - 0.00068X2 + 0.0000014X3

Mesomorphy calculation Record height (H), humerus breadth (HB) and femur breadth (FB), max calf girth and max upper arm girth, with the arm flexed to 45º and tensed. Calculate corrected arm (AG) and calf girth (CG) by subtracting triceps and medial calf skinfolds from the respective girths. Substitute these values in the following equation: Mesomorphy = 0.858HB + 0.601FB + 0.188AG + 0.161CG - 0.131H + 4.5

Ectomorphy calculation Record height in cm and weight in kg Divide the height by the cube root of weight to calculate the reciprocal of the ponderal index or RPI. The magnitude of the RPI determines which formula is used to calculate ectomorphy. If RPI > 40.74, Ectomorphy = 0.732RPI - 28.58 If 39.65 < RPI < 40.74, Ectomorphy = 0.463RPI - 17.615 If RPI < 39.65, Ectomorphy = 0.5

Rounding From equations - round decimal to one decimal place eg. 3.1-4.7-1.4 For general description, plotting and category boundaries, round to the nearest half unit eg. 3-4-1 Rating form are in nearest half units

Somatotype Attitudinal Distance The distance between any two somatopoints (in 3D space) - calculated in component units SAD A,B = [(endoA-endoB)2 + (mesoA - mesoB) 2 + (ectoA - ectoB) 2 ]0.5 where A and B are two somatotypes Somatotype Attitudinal Mean The average 3D distance between all somatoplots and their mean

Physique advantages Absolute strength, injury resistance, hypothermia resistance, positive self image Cardiac health Low energy cost of locomotion power:weight ratio Injury protection via diminished forces Absolute mass for blocking sports; Hypothermia resistance, floatation

Physique disadvantages Power at expense of endurance; poor heat dissipation; exercise can become obsessive in bodybuilders Low power: weight; high energy cost of locomotion; impaired heat dissipation; cardiac risk factors; low self esteem Lack of upper body strength; risk of diminished self image

Somatotypes of 106 male athletes Mesomorphy Endomorphy Ectomorphy Data from Stewart & Hannan, (2000)

Somatotype Convergence Athletes’ physiques evolve according to training status and periodisation. Variation in physique (i.e. SAM) reduces as competitive standard increases, as the athletes become increasingly selected Early training Performance peak Discus throwers High jumpers 400m runners Sumo wrestlers

Somatotype comparison in cyclists Reference: Anthropometrica Road racing cyclists’ data from Stewart & Hannan (2000)

Summary The relevance of somatotype in sport Each component independently affects performance in most sports Talent identification for sporting potential of individuals Tool for matching individuals with sports which they may have advantages for Tool for determining training goals and outcomes Affects body image and self esteem

References Anthropometrica: Norton, K & Olds, T. (Eds) (1996) University of New South Wales Press Carter J.E.L. and Heath, B.H. (1990). Somatotyping: Development and applications. Cambridge, UK, Cambridge University Press. Eston, R. & Reilly, T. (Eds) (2001) Kinanthropometry and exercise physiology lab manual, volume 1. London: Routledge