9 Heath-Carter Methods of Somatotyping

Dr. Mary Grace Tungdim

Contents of this unit

1. What is somatotyping?

2. The Heath-Carter methods of somatotyping:

3.0 Anthropometric Method for Calculating the Somatotype:

3.1 Equipment for anthropometry

3.2 Accuracy & Reliability of measurements

3.3 The anthropometric somatotype can be calculated in two ways as illustrated below:

3.4 Principles of the calculations

3.5 Height-Weight ratio Calculation

3.6 Limitations of the rating form

3.7 Equations for a decimal anthropometric somatotype

3.8 Checking the results of the calculation

4. Photoscopic Somatotype Rating Method

5. The Anthropometric plus photoscopic somatotype Rating Method

6. Somatotype categories

7.0 Plotting the Somatotype

7.1 The three-dimensional somatotype

8. Somatotype Analysis

Learning Outcomes

1. The learner will come to know about somatotyping, the development and the Heath-Carter methods of somatotyping.
2. They will also be able to understand the different rating methods, the different categories and plotting the somatotype.

1. What is somatotyping?

The technique of somatotyping is used to appraise body shape and composition. Therefore, somatotyping involves quantification of the shape and composition of the human body. It is expressed in a three-digit rating which represents endomorphy, mesomorphy and ectomorphy components respectively, always in the same order. Endomorphy refers to the relative fatness, mesomorphy is the relative musculo -skeletal robustness, and ectomorphy is the relative linearity or slenderness of a physique (Carter & Heath, 1990).

For example, a 3-5-2 rating is recorded in this manner wherein endomorphy is rated as 3, mesomorphy as 5 and ectomorphy as 2. These numbers give the magnitude of each of the three components. Any component which has a rating of ½ to 2½ is considered low, 3 to 5 as moderate, 5½ to 7 as high, and 7½ and above as very high (Carter & Heath, 1990). The rating is phonotypical as it is based on the concept of geometrical size-dissociation and applicable to both genders from childhood to old age.

2. The Heath-Carter methods of somatotyping:

It is the most commonly used method of somatotyping today formulated by J.E. Lindsay Carter and Barbara Honeyman Heath. Heath and Carter (1967) combined the modified form of Parnell’s M.4 Technique to make the Heath’s system more objective. They defined somatotype as the ‘present morphological conformation’ and expressed the primary components of physique that allow us to understand personal phenological characteristics and body composition three-dimensionally. The first component or endomorphy refers to relative fatness and leanness. The second component refers to a condition where mesomorphy has more developed skeletal frame compared to height. The third component or ectomorphy refers to a condition where somatotype is of linearity. When deciding ratios (grades), HWRs take up largely, but not entirely. This will be assessed based on the first and the second stretched-outness, longitudinal distribution, or body form. Extremes of each component are found in both ends of the scale. Lower ratios of the first element mean that there is an extremely small amount of non-essential fat. On the other hand, higher ratios relate to higher non-essential fat ratios. If the second element is lower, skeletal frames are light and muscles are not definite. If it is higher, musculoskeletal system is significantly developed. If the third element is lower, weight takes up more in comparison with height. On the other hand, if it is higher, overall, weight takes up much less in comparison with height (Choi et al, 2013). At the same time, bodies or constituent parts are linear and HWRs is higher. There are three ways/techniques of obtaining the somatotype.

i. The anthropometric method, in which anthropometry is used to estimate the criterion somatotype.

ii. The photoscopic method, in which ratings are made from a standardized photograph.

iii. The anthropometric plus photoscopic method, which combines anthropometry and ratings from a           photograph.

3.0 Anthropometric Method for Calculating the Somatotype:

3. 1 Equipment for anthropometry

The equipment includes a stadiometer or anthropometer, weighing scale, sliding caliper, a flexible steel tape, and a skinfold caliper. For accurate measuring of biepicondylar and Femur breadths the caliper branches must extend to 10 cm and the tips should be 1.5 cm in diameter (Carter, 1980) . The maximum pressure exerted by the Skinfold calipers should be 10 gm/mm2 over the full range of openings. There are different types of calipers viz.; Harpenden caliper, Holtain calipers and others.

3. 2 Accuracy & Reliability of measurements

The advantages of anthropometry are lost unless the measurements are accurate and reliable (i.e. precise). It is essential to learn precise measurement techniques and accurate calculations. Although calculation of the Heath-Carter anthropometric somatotype is an objective procedure, the validity of the rating depends on the reliability of the measurements used. Investigators should report test-retest reliability of the measurements

3. 3 The anthropometric somatotype can be calculated in two ways as illustrated below:

    (A) Enter the data onto a somatotype rating form.

(B) Enter the data into equations derived from the rating form.

Figures 2 and 3 are examples of calculations using the rating form to calculate the somatotype. After all the measurements have been recorded on an appropriate recording form and average or median values calculated, it is then transferred to the rating form. A blank rating form is provided in Figure 1.

The following steps are followed to fill in the rating form:

• (1) Record pertinent identification data in top section of rating form. Endomorphy rating (steps 2-5)
• (2) Record the measurements for each of the four skinfolds.
• (3) Sum the triceps, sub scapular and supraspinale skinfold thicknesses; record the sum in the box opposite SUM 3SKINFOLDS. Correct for height by multiplying this sum by (170.18/height in cm).
• (4) Circle the closest value in the SUM3 SKINFOLDS table to the right. The table is read vertically from low to high in columns and horizontally from left to right in rows. “Lower limit” and “upper limit” on the rows provide exact boundaries for each column. When the values of SUM3 SKINFOLDS are within 1 mm of the limit, they circled. In most cases the value in the row “midpoint” is circled.
• (5) In the row for endomorphy circle the value directly under the column for the value circled in number (4) above. Mesomorphy rating (steps 6-10)
• (6) The values of height and breadths of humerus and femur are to be recorded in the appropriate boxes. The skinfold thicknesses are corrected before recording girths of biceps and calf.
• (7) In the height row directly to the right of the recorded value, circle the height value nearest to the measured height of the subject.
• (8) For each bone breadth and girth circle the number nearest the measured value in the appropriate row.
• (9) Deal only with columns, not numerical values for the two procedures below. Find the average deviation of the circled values for breadths and girths from the circled value in the height column as follows:
  • (a) Column deviations to the right of the height column are positive deviations. Deviations to the left are negative deviations.
  • (b) Calculate the algebraic sum of the ± deviations (D). Use this formula: mesomorphy = (D/8)+4.0. 
  • Round the obtained value of mesomorphy to the nearest one-half (½) rating unit.
• (9) In the row for mesomorphy circle the closest value for mesomorphy obtained in number 9 above. (If the point is exactly midway between two rating points, circle the value closest to 4 in the row. This conservative regression toward 4 guards against spuriously extreme ratings.)

Ectomorphy rating (steps 11-14).

• (11) Record weight (kg).
• (12) Obtain height divided by cube root of weight (HWR). Record HWR in the appropriate box.
• (13) Circle the closest value in the HWR table to the right. (See note in number (4) above.)
• (14) In the row for ectomorphy circle the ectomorphy value directly below the circled HWR.
• (15) Move to the bottom section of the rating form. In the row for Anthropometric Somatotype, record the circled ratings for Endomorphy, Mesomorphy and Ectomorphy.
• (16) Sign your name to the right of the recorded rating.

Figure 3. Calculations of the anthropometric somatotype for subject 573 using the rating form. 3.4 Principles of the calculations

The two important principles in understanding the calculation of mesomorphy on the rating form are as follows:

• (1) When the measurements of bone breadths and limb girths lie to the right of the circled height column, the subject has greater musculo -skeletal robustness relative to height (i.e. higher mesomorphy) than a subject whose values lie to the left of the column of height. The best index of average musculo-skeletal development relative to height is ascertained from the average deviation of the circled values for breadths and girths.

• (2) The table is constructed so that the subject is rated 4 in mesomorphy when the average deviation falls in the height column of the subject, or when the four circled values fall in the subject’s height column. That is, the average deviation (±) to the left or right of the height column is added to or subtracted from 4.0 in mesomorphy.

3.5 Height-Weight ratio Calculation

The height- weight ratio (HWR) is obtained when height is divided by the cube root of weight (stature/mass1/3) or from a nomograph (Sheldon, 1954).

3.6 Limitations of the rating form

Although the rating form provides a simple method of calculating the anthropometric somatotype, especially in the field, it has some limitations as follows:

1. The mesomorphy table at the low and high ends does not include some values for children, or for large subjects like heavy weightlifters. Nonetheless, the mesomorphy table can be extrapolated at the lower and upper ends for these subjects.

2. Some rounding errors may occur in calculating the mesomorphy rating, because the subject’s height often is not the same as the height in the column. However, if the anthropometric somatotype if regarded as an estimate this second limitation is not a serious problem. Nevertheless, the following procedures described in Carter (1980) and Carter and Heath (1990) can correct these problems.

3.7 Equations for a decimal anthropometric somatotype

The other method of obtaining the anthropometric somatotype is by means of equations into which the data are entered.

The equation to calculate endomorphy is:

Endomorphy=-0.7182 + 0.1451 (X)-0.00068 (X2) + 0.0000014 (X3)

Where X = (sum of triceps, sub scapular and supraspinale skinfold thicknesses) multiplied by (170.18/height in cm). This is called height -corrected endomorphy and is the most preferred method for calculating endomorphy.

The equation to calculate mesomorphy is:

Mesomorphy = [(0.858 x humerus breadth) + (0.601 x femur breadth) + (0.188 x corrected armgirth) + (0.161        x corrected calf girth)]– (height x 0.131)+ 4.50.

Corrected arm girth= Arm girth – triceps skinfold thickness Corrected calf girth= Calf girth – calf medial skinfold thickness

Three different equations are used to calculate Ectomorphy according to the height-weight ratio:

Ectomorphy= 0.732 x HWR-28.58

Where, HWR= Height in cm divided by cube root of weight in kg

If HWR is equal to or less than 40.75 but greater than 38.5

Ectomorphy= 0.463x HWR-17.63

If HWR is equal to or less than 38.25

Then, Ectomorphy= 0.1

For subjects B-188 and 573 respectively (Figures 2 & 3), the resulting somatotypes (using height corrected endomorphy) are 3.0-2.1-4.8 and 1.6-5.4-3.2.

The preceding equations, derived from data used by Heath and Carter (1967), used metric units. The equation for endomorphy is a third degree polynomial. The equations for mesomorphy and ectomorphy are linear. When the HWR is below 40.75 a different equation is used for ectomorphy. If the equation calculation for any component is zero or negative, a value of 0.1 is assigned as the component rating, because by definition ratings cannot be zero or negative.

3.8 Checking the results of the calculation

There are several ways to check your results for measurement or calculation errors.

Using the rating form examples in Figures 2 and 3, the resulting somatotypes rounded to the nearest half-unit, are 3-2-5 and 1½-5½- 3 for subjects B-188 and 573 respectively.

Certain somatotype ratings are not biologically possible, although our examples are not among them. For example, a 2-2-2 or a 7-8-7 are impossible somatotypes. Generally, somatotypes high in endomorphy and/or mesomorphy cannot also be high in ectomorphy. Conversely, those high in ectomorphy cannot be high in endomorphy and/or mesomorphy; and those low in endomorphy and mesomorphy must be high in ectomorphy.

If the calculation for any component is zero or negative, a value of 0.1 is assigned as the component rating, because by definition ratings cannot be zero or negative. The photoscopic rating would be one -half (½). If such low values occur the raw data should be checked. Values less than 1.0 are highly unlikely to occur for endomorphy and mesomorphy, but are not unusual for ectomorphy. Component ratings should be rounded to nearest 0.1 of a unit, or nearest half-unit depending on their subsequent use.

After the values are entered into the equations (either by calculator or computer program) rather than onto the rating form, it is impossible to check the pattern of values in either the endomorphy or mesomorphy section as in the rating form, although the raw values can be examined for errors. This is a limitation of using the equations. Further checking can be done for either method by using the HWR and by plotting the somatotype.

There is a relationship between the HWR and the likely somatotypes (see Fig. 4) . The somatotypes in the rows are those most likely to occur for the given HWR. For example, given a HWR of approximately 49.6, the most likely somatotypes are 1- 1-8, 1-2- 9 or 2-1-9. (The hyphens are left out of the somatotypes to conserve space.) The next most likely somatotypes are those in the rows directly above and below the row for 49.6. If none of these somatotypes match or are not close when interpolating for half- unit ratings, there may be errors in the data or calculations. However, other factors such as heavy meals or dehydration can affect body weight sufficiently to alter the “normal” HWR.

For subject 573, HWR = 43.4, and Figure 4 shows that in the row for a HWR of 43.64 the somatotypes 1- 6-3 and 2-5-3 occur. His 1½-5½ -3 is a combination of these two ratings, therefore his anthropometric rating agrees with that expected from the HWR table. For subject B-188, HWR = 45.6, her 3-2- 5 somatotype appears in the row above that for her HWR. Her ectomorphy is borderline between 4½ and 5, which suggests that she might be a 3- 2-4½, i.e. half way between the two rows. The somatotypes for both subjects appear to be reasonable.

A = height in inches / cube root of weight in pounds

B = height in centimeters / cube root of mass in kilograms

Figure 4.Distribution of somatotypes according to the HWR (height/weight1/3).

4. Photoscopic Somatotype Rating Method

The Heath-Carter somatotype ratings are based upon standard somatotype photographs together with a record with a record of age, height and weight. The somatotype photograph is a valuable record of the physique, especially when change is expected and for longitudinal growth studies. It can be used as a supplement to the anthropometric somatotype rating, in assessment of body image, and in association with the anthropometric profile.

The procedures for photoscopic rating are:

The following procedures assume that the rater has photographs of 20 or more subjects.

• Arrange the photographs from high to low according to the calculated HWR of each subject.
• Group the photographs by their proximity to given HWR rows in Figure 4.
• Beginning with the photograph(s) with the highest HWR’s, arrange the photographs in each HWR category according to inspectional judgment of relative values or dominance of three components.
• Record on the photoscopic rating form(Figure 5), the first impression of the relative values of the three components.
• On a separate sheet of paper write down the somatotypes with same or similar relative dominance as the estimated rating and lying on the same HWR row.
• After making ratings of all photographs at the same HWR group, compare them to check their similarities and differences on each component for compatibility with the HWR.
• Repeat the above process for each successive HWR group.
• When all HWR groups have estimated ratings and have been compared, arrange the photographs on a large surface, first, in order of increments of endomorphy. Repeat for mesomorphy and ectomorphy.
• Calculate means for each of the three components and for the HWR.

The somatotype photograph requires standardized poses of front, side and rear views of the subject. The recommended minimal equipment consists of a good quality 35 mm camera, with an 80 mm lens and attached flash. The camera should be mounted on a tripod, at 5.8 m from the subject and the lens height at approximately mid -stature for most subjects in the sample. Commercially developed standard color print film (ASA 200 or 400) is quite satisfactory and relatively inexpensive. The subject should be dressed in minimal clothing such as light-weight swim suits (single or two-piece), or running shorts. A more permanent somatotype station should include a data board, turntable, standard scale, white background, and flood or flash lights. Digital photography is now a viable option if care is taken to keep the focal length long to reduce distortion of the physique.

5. The Anthropometric plus photoscopic somatotype Rating Method

The following are required for the anthropometric plus photoscopic somatotype rating:

1. Standard somatotype photographs.
2. The distribution of somatotypes according to HWR (Figure 4).
3. The photoscopic rating form (Figure 5)
4. The Heath Carter somatotype rating form (Figure 1).

• Arrange a series of somatotype photographs and their anthropometric somatotype rating forms in groups ranked by HWR.
• When any one-half unit category is large, subdivide the group in three parts – upper limit, midpoint and lower limit.
• Beginning with the group highest in ectomorphy, arrange them from low to high according to the anthropometric ratings in endomorphy. If all subjects are equal in endomorphy or if there is a greater range in mesomorphy, rank them from low to high in anthropometric mesomorphy ratings.
• Record on a worksheet the identification number and the anthropometric rating of the first subject- usually with the highest HWR.

6.  Somatotype categories

Somatotypes with similar relationships between the dominance of the components are grouped into categories named to reflect these relationships. Figure 7 shows somatotype categories as represented on the somatochart. Subject 573 is an ectomorphic mesomorph (or ecto-mesomorph), and subject B- 188 is an endomorphic ectomorph (or endo-ectomorph). All other somatotypes plotted within the same area are assigned the same category name. The frequencies of somatotypes within categories (or combined categories) can be used to describe the overall distribution of samples or for comparing them using a Chi-square analysis.

Figure 8. Somatotype categories labeled according to Carter and Heath (1990). Somatoplots falling within the same area are grouped by category.

The definitions of 13 categories are based on the areas of the 2-D somatochart (Carter and Heath, 1990) as given below:

• 1) Central: no component differs by more than one unit from the other two.
• 2) Balanced endomorph: endomorphy is dominant and mesomorphy and ectomorphy are equal (or donot differ by more than one-half unit).
• 3) Mesomorphic endomorph: endomorphy is dominant and mesomorphy is greater than
• 4) Mesomorph-endomorph: endomorphy and mesomorphy are equal (or do not differ by more than one-half unit), and ectomorphy is smaller.
• 5) Endomorphic mesomorph: mesomorphy is dominant and endomorphy is greater than
• 6) Balanced mesomorph: mesomorphy is dominant and endomorphy and ectomorphy are equal (or donot differ by more than one-half unit).
• 7) Ectomorphic mesomorph: mesomorphy is dominant and ectomorphy is greater than
• 8) Mesomorph-ectomorph: mesomorphy and ectomorphy are equal (or do not differ by more than one-half unit), and endomorphy is smaller.
• 9) Mesomorphic ectomorph: ectomorphy is dominant and mesomorphy is greater than
• 10) Balanced ectomorph: ectomorphy is dominant and endomorphy and mesomorphy are equal (or do notdiffer by more than one-half unit).
• 11) Endomorphic ectomorph: ectomorphy is dominant and endomorphy is greater than
• 12) Endomorph-ectomorph: endomorphy and ectomorphy are equal (or do not differ by more than one-half unit), and mesomorphy is lower.
• 13) Ectomorphic endomorph: endomorphy is dominant and ectomorphy is greater than

The 13 categories can be simplified into four larger categories:

• (1) Central: no component differs by more than one unit from the other two.
• (2) Endomorph: endomorphy is dominant, mesomorphy and ectomorphy are more than one – half unit lower.
• (3) Mesomorph: mesomorphy is dominant; endomorphy and ectomorphy are more than one – half unit lower.
• (4) Ectomorph: ectomorphy is dominant, endomorphy and mesomorphy are more than one-half unit lower.

7.0 Plotting the Somatotype

Traditionally, the three-number somatotype rating is plotted on a two-dimensional somatochart using X,Y coordinates derived from the rating (see Fig. 5). The coordinates are calculated as follows:

X = ectomorphy – endomorphy

Y = 2 x mesomorphy – (endomorphy + ectomorphy)

For subject 573, X = 1.5, and Y = 6.5. For subject B-188, X = 2.0, and Y = -4.0. These points on the somatochart are called somatoplots. If the somatoplots for the subject is far from that expected when compared to a suitable reference group, check the data and calculations. Because Figure 5 is quite crowded with numbers, the final somatoplots could be projected onto a somatochart without the numbers.

Figures 6 A.Bare Two Blank Somatocharts, One With Printed Somatotypes And One Without.

7.1 The three-dimensional somatotype

As the somatotype is a three-number expression meaningful analyses can be conducted only with special techniques. Somatotype data can be analyzed by both traditional and non-traditional descriptive and comparative statistical methods. Although descriptive statistics are used for each of the components, comparative statistics should be made in the first instance using the whole (or global) somatotoype rating. This is followed by analysis of separate components. Some useful definitions are given below:

Somatopoints(S). A point in three-dimensional space determined from the somatotype which isrepresented by a triad of x, y and z coordinates for the three components. The scales on the coordinate axes are component units with the hypothetical somatotype 0-0-0 at the origin of the three axes.

Somatotype attitudinal distance (SAD).The distance in three dimensions between any twosomatopoints.Calculated in component units.

Somatotypes attitudinal mean (SAM). The average of the SADs of each somatopoints from the mean somatopoints (S) of a sample.

The SAD represents the “true” distance between two somatopoints (A and B). The SAD is calculated as follows:

SADA,B=v[(endomorphyA–endomorphyB)2+ (mesomorphyA–mesomorphyB)2+ (ectomorphyA – ectomorphyB) 2]

Where A and B are two individuals, two different times for one individual, or two means. The SAM is calculated by dividing the sum of the SADs from their mean somatopoints by the number of subjects.

8.0 Somatotype Analysis

The most widely applied method for obtaining the somatotype is the anthropometric method of Heath and Carter (1967), which has been modified slightly since it was first, published. Important changes include the conversion to a rating form in metric units, the use of a height adjustment for endomorphy which is now standard procedure, and the use of equations, instead of the rating form, to calculate the component ratings (Carter and Heath, 1990). Recently, Rempel (1994) has developed modifications of the rating form and equations so that the scales are truly size dissociated. His modifications are sound and when tested further they will probably be accepted as the preferred methods for calculating somatotype ratings.

Analysis of the three-number somatotype rating presents some unusual problems to the uninitiated. How should such a rating be analyzed? Early solutions typically involved either analyzing the three component ratings separately, or grouping somatotypes and comparing the frequencies. During the 1970s and 1980s more sophisticated analyses, appropriate for analysis of the somatotype as a whole, were developed. These were summarized in a series of publications, Hebbelinck et al. (1973), Duquet and Hebbelinck (1977), Carter (1980), Carter et al. (1983) and Carter and Heath (1990). An important element of these developments was the ability to analyze whole somatotypes in two or three dimensions using appropriate equations, which led to application of conventional statistical analysis. These equations quantified the distances between somatotypes. The two and three- dimensional distances between pairs of somatotypes are called the somatotype dispersion distance (SDD) and somatotype attitudinal distance (SAD) respectively. The average of the distribution of somatotypes about their mean is called the somatotype dispersion mean (SDM) in two dimensions, and somatotype attitudinal mean (SAM) in three dimensions. Because the SAD and SAM, which are based in three dimensions, contain more accurate information about the true distances between somatotypes than the SDD and SDM, which are based in two dimensions, the three dimensional approach is recommended for most analyses.