The material posted on this article about somatotypes is supplemental information to first aid and CPR training. This extensive information is designed to give candidates an understanding of the different body types and how it can relate to first aid scenarios. To learn basic first aid and to apply this information register for a first aid class.
I. Body Image
Body image – the picture an individual has of her own body which she forms in her mind. Individuals assign qualities of size, shape, and attractiveness to their bodies in terms of personalized standards which may bear little
relation to actual body characteristics. Some people love and parade their bodies; others are ashamed of their bodies and hide them.
The primary determinants of body appearance are
- (a) the skeleton
- (b) muscle
- (c) fat
II. The Somatotype
The somatotype is a quantitative description of the present structure and composition of the body. This method of physique classification was developed by W.H. Sheldon in the 1920’s to 1950’s. The real value of somatotyping lies in its contribution toward a better understanding or the individual.
A. Sheldon’s Somatotype
Sheldon designated three primary components of body build:
- Endomorphy – refers to the relative predominance of soft roundness throughout the body.
- Mesomorphy – refers to relative predominance of muscle, bone, and connective tissue.
- Ectomorphy – refers to the relative predominance of linearity and fragility.
Sheldon rated each component on a seven point scale to indicate it’s relative contribution to the total physique. This three numeral rating of a physique is called the “somatotype”.
First numeral = endomorphy
Second numeral = mesomorphy
Third numeral = ectomorphy
Most physiques are dominated by two components.
641 = mesomorphic endomorph
461 = endomorphic mesomorph
244 = mesomorph – ectomorph
333 = balanced
Sheldon studied 15,000 men and identified 88 basic somatotypes. 27 of these somatotypes accounted for 83% of the male population.
B. Male versus Female Somatotypes
On a somatoplot, the distribution of female physique types differs from the male distribution of physique types – sexual dimorphism. Females are more endomorphic and less mesomorphic than males. 1976 – 1978 Canadian data.
Manual. Average somatotypes for males and females aged 15 to 60 years:
Males: 3.9 – 5.2 – 1.9
Females: 4.7 – 4.0 – 2.2
There are also differences in average somatotypes among ethnic groups.
C. Methods of Determining Somatotypes
Several systems of somatotyping have been developed. The Sheldon method and the Heath-Carter method have been the most widely used. The Heath-Carter method has been extensively used on samples of
athletes. In the Heath-Carter method, the rating scale was opened at the top end, from 7 to 12, to accommodate extreme body types. The somatotype doesn’t tell you anything about a person’s height, or about body proportionality – trunk length vs. leg length, etc.
D. Heritability of Somatotype Components
Both genes and environment are important in determining differences in somatotype components. The heritabilities for mesomorphy (85%) and ectomorphy (65%) are higher than for endomorphy (28%)
E. Physical Performance and Somatotype
Both male and female athletes are more mesomorphic and less endomorphic than non-athletes of the same age. There are characteristic somatoplot distributions for each sport. The higher the level of sport the lower the variation in somatoplot distribution.
USA national men’s rugby team – mean somatotypes for backs = 2.4-5.9-1.8; forwards = 3.1-6.6-1.2. The USA national team players have similar somatotypes to national team players from France, Australia, and South Africa.
Some sports are more tolerant of somatotype variation than other sports. A high mesomorphy is positively correlated with physical fitness tests and endomorphy is negatively correlated. Strength and speed-dependent athletes are more mesomorphic and less ectomorphic than distance-dependent athletes. Very seldom do men and women low in mesomorphy succeed at a high level in sports.