Arthur StewartSomatotype

Mandy PlumbDepartment of Orthopaedics

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

•Endomorphy

•Mesomorphy

•Ectomorphy

Average value

4

4

4

5

5

5

6

6

6

3

3

3

2

2

2

lean fat

muscularslender

lightheavy

Somatotype Components

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.

HistorySomatotype

• Photoscopic• Anthropometric*

– somatotype rating form– computer-calculated

• Combined– the criterion measure

• Stadiometer• Weighing scale• Bone caliper• Skin caliper• Anthropometric tape

Methods *Equipment required

Somatotype Assessment

Somatotype Rating Form

Somatochart•Central•Endomorph•Mesomorph•Ectomorph

• Endomorphy– Roundness or fatness, based on 3

skinfolds Independent of size• MesomorphyMesomorphy

– Musculo-skeletal robustness, based on elbow & knee breadths, and corrected girths of calf and upper arm

• EctomorphyEctomorphy– 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

(Heath & Carter, 1967)

Anthropometric Somatotype Assessment

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.

Measurements Required

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

Endomorphy

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

Mesomorphycalculation

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

calculation

Ectomorphy

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 DistanceThe 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 MeanThe average 3D distance between all somatoplots and their mean

Cardiac healthLow energy cost of locomotionpower:weight ratioInjury protection via diminished forces

Absolute strength, injury resistance, hypothermia resistance, positive self image

Absolute mass for blocking sports; Hypothermia resistance, floatation

Physique advantages

Lack of upper body strength; risk of diminished self image

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

Physique disadvantages

Endomorphy

Ectom

orph

y

Mesomorphy

Data from Stewart & Hannan, (2000)

Somatotypes of 106 male athletes

Sumo wrestlers

High jumpers

Discus throwers

400m runners

Early training

Performance peak

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

Somatotype Convergence

Road racing cyclists’ data from Stewart & Hannan (2000)

Somatotype comparison in cyclistsReference: Anthropometrica

• 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

The relevance of somatotype in sport

Summary

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