BR IEF COMM UNICAT1ONS Changes in Somatotypes of European Males between 17 and 24 Years' J . E. LINDSAY CARTER AND J A N A PABIZKOVA Department ofPhysical Education, S u n Diego State Uniuersity. S u n Diego, California, 1J.S.A. 92182 and V U FTVS, Charles Unioersity, lljezd 450,11807Prague 1, C.S.S.R K E Y WORDS Somatotype. Somatotype stability. Young males ABSTRACT I n order to examine the possible changes in somatotype of young males, 14 boys who had been somatotyped annually from 11 to 18 years by t h e Heath-Carter anthropometric rating method were re-somatotyped at 24 years. The analysis focused on years 17, 18 and 24. Discriminant analysis, somatotype dispersion indices and distances, and the I-index were used to analyze the data. The findings showed a significant shift in somatotype from ectomorphmesomorph towards endo-mesomorphy between 17 and 24 years. This shift was greater than t h a t observed by Zuk ('58), and was in the same direction. I t is hypothesized t h a t t h e somatotypes of males become more endo-mesomorphic from 17 years to the mid-twenties. Although t h e r e have been studies on changes in somatotypes of children, little a t tention has been paid to possible changes in adults. Several studies, all using the HeathCarter somatotype method (Carter, '751, have provided little information on this problem. Zuk ('58) showed t h a t young males become more endo-mesomorphic and less ectomorphic between 17 and 33 years. Carter and Phillips ('69) showed that, in a group of middleaged males, cardiovascular exercise reduced endomorphy while a non-exercising control group increased endomorphy during a twoyear period. In a study of young males who underwent strenuous physical training for four months, Carter and Rahe ('75) showed t h a t mesomorphy increased and endomorphy and ectomorphy decreased. A recent study by PaEizkova and Carter ('76) examined the stability of somatotypes of Czechoslovakian boys followed longitudinally from 11 until 18 years. The authors concluded t h a t the individual somatotypes of boys changed considerably but the somatoplots for each year were similar. Because of t h e need for more data on t h e longitudinal changes in somatotypes of young men the purpose of this study was to follow and compare the somatotypes of Czechoslovakian young men at 17, 18 and 24 years. AM. J . PHYS. ANTHKOP. (1978) 48: 251-254. METHODS The subjects were 14 males from a previous study (Pafizkova and Carter, '76) who were remeasured at age 24 by the reported methods, but whose physical activity since t h e last test was not controlled. (These 14 subjects were the only ones of the original 39 who were available for remeasurement.) The HeathCarter anthropometric somatotypes were calculated, plotted on somatocharts, and analyzed by means of t h e somatotype dispersion index (SDI), somatotype dispersion distance (SDD), and I-index (Carter, '75; Ross and Wilson, '73; Ross, '76). Descriptive statistics were calculated at each year from 11 to 18, and a t 24 years of age, for height, weight, and t h e three somatotype components. RESULTS From 11 to 17 years the means for age, height, weight, endomorphy,mesomorphy, and ectomorphy were similar to the means of the original group (n = 39) from which they were drawn, indicating t h a t t h e sample did not contain any bias with respect to size and shape. ' This study was supported in part by a grant from the San Diego State University Foundation. The authors gratefully acknowledge the assistance of Stephen P Auhry in developing the somatotype cumputer programs. 251 252 J. E. LINDSAY CARTER AND JANA PARIZKOVA MESOMORPHY \ ENDOMOBPHY EC TOMORPHY Fig. 1 Mean somatoplots of Czechoslovakian males (circles) somatotyped at ages 11 through 18 (numbers 1 through 8 ) and at 24 (9).The triangles are the mean somatoplots of Zuks ('58)males at ages 17 and 33. A stepwise discriminant analysis, using t h e above variables (except age), was applied to detect significant differences among t h e 17, 18 and 24 year-olds. The greatest discrimination was due to weight (increase), followed by endomorphy (increase), with significant Fratios (p > 0.05) between 17 and 24, and 18 and 24 years. There was no discrimination between ages 17 and 18 at any of the steps. At steps three, four, and five, the addition of mesomorphy (increase), height (increase), and ectomorphy (decrease), only served to discriminate between 17 and 24 years. The percentage of cases correctly classified into age groups were 57% (17 years), 43% (18 years), and 57% (24 years). The mean somatoplots for each of the nine years were plotted on t h e X, Y coordinates of t h e somatochart as-shown in figure 1. The mean somatotypes (S)and their X,Y coordinates for 17, 18 and 24 years were: SI7= 1.71 - 4.04 - 3.36 (1.65, 3.00); S18 = 2.39 - 4.68 - 2.96 (0.57, 4.00); and = 2.68 - 5.39 2.54 (-0.14, 5.56). The means remained very close to t h e 2-43.5 somatotype from 11-17 years, with a n average SDD between consecutive mean somatoplots of 0.91. Between 17 and 18, and 18 s,, 253 SOMATOTYPES OF YOUNG MALES MES OMORPBY L’ - I / / \ / L ’ ENDOMORPHY \ - 2 Y ‘A ECTOMORPHY and 17 years @,I, plotted Fig. 2 The I-index for the somatoplots of Czechoslovakian males ages 24years 6,) with centers on 3, andS, and radii equal to SDI, and SDI, respectively. The I-index equals 28.8, and the SDD between S, and S, equals 4.02. and 24 years the SDD’s were 2.11 and 1.99 respectively, with the means moving in a northwesterly direction towards endo-mesomorphy and away from ectomorphy, to a n approximate somatotype of 2.5-5.5-2.5 (a balanced mesomorph). Both SDD’s were significant beyond the 2.5% level of confidence for a onetailed t-test. The SDD between 17 and 24 years was 4.02 (p > 0.01)with a direction of -50.5”. In order to test the significance of the differences between 17 and 24 years by somatotype components, a two-tailed paired t - t e s t was applied to the mean values for endomorphy, mesomorphy, and ectomorphy. Endomorphy (p > 0.05) and mesomorphy (p > 0.01) increased and ectomorphy (p > 0.01) de- 254 J. E. LINDSAY CARTER AND JANA PARIZKOVA creased. Apparently, the shift in the somatoplots was accounted for by significant changes in all three components. The mean somatoplots for Zuk's ('58) data are also shown in figure 1. The SDD between 17 and 33 years was 2.09 - a value which was about the same in magnitude and direction as each of the SDD's from 17 to 18 and 18 to 24 years, but about half the SDD from 17 to 24 years for the present study. In order to study the individual patterns at 17, 18 and 24 years, the somatoplots for each of the 14 subjects were plotted. All subjects moved in the direction of endo-mesomorphy between 17 and 24 years. Between 1 7 and 78 years one subject did not change, and one reduced endomorphy by a half-unit. Between 18 and 24 years two subjects did not change, one subject became less endomorphic, and one more ecto-mesomorphic. The rank difference correlations between ages 17 and 24 for endomorphy, mesomorphy, and ectomorphy were 0.91, 0.94, and 0.96 respectively. These correlations are much higher t h a n those reported for a 7-year span in the younger groups (Pafizkova and Carter, '761, indicating a greater relationship within components during early adulthood. Ross ('76) has described how the basic concepts of t h e SDD and SDI may be used to derive a n I-index to show the amount of commonality between samples. The I-index is a ratio derived from the intersection of circles drawn with centers on the mean somatoplots (S,and S,)and radii equal to SDI, and SDI,. Thus, the I-index is based on a geometrical model representing any pair of somatoplots, and is described a s I = (area in common/sum of area of 2 circles-area not in common) x 100. When I = 100, the circles are concentric and have equal radii, and when I = 0, there is no overlapping between t h e circles. The I-index was applied to the somatoplots at all ages, but only the circles representing the I-index of the 17 and 24 year-olds are shown in figure 2. The I - i n d i c e s b e t w e e n s e q u e n t i a l y e a r s (11 through 17) averaged 64.1 (low index = 52.0, high index = 78.4), but the smallest values were between 24 years and ages 13 through 17 (I = 22.3; low index = 16.5, high index = 28.2). Between 17 and 18, I = 52.0, between 17 and 24 I = 28.8, and between 18 and 24 I = 59.5. This analysis shows t h a t there is considerable overlap in somatoplots in the adoles- cent years but t h a t between 17 and 24 years the somatoplots are displaced in the direction of endo-mesomorphy and show less overlap. The subjects increased 9.8 kg in mean weight from 17 to 24 years, and this weight can be accounted for by the increases in endomorphy and mesomorphy. This finding is also supported by observed mean increments in percentage of body fat (10.3-11.9%)and in lean body mass (63.3-68.1kg) (Pafizkova, '77). On the basis of the foregoing analysis i t is apparent t h a t the subjects had a significant shift in somatotype towards endo-mesomorphy. The consistency of this shift is in contrast t o the inconsistency observed in the younger males (Pafizkovk and Carter, '76.1. In addition, the shift was greater t h a n that observed by Zuk ('581, but was in the same direction. I t is important to note that this study and those referred to all used the HeathCarter somatotype method which, although using the same terminology as the traditional somatotype methods of Sheldon and his colleagues, differs in concept and method. One difference is that somatotypes are rated as present somatotypes and permanence is not assumed. The Zuk ('58) study was one of the first studies in which Heath rated the subjects using her modifications of somatotyping. Although these studies are limited, the following hypothesis is proposed for further testing: The somatotypes of males become more endomesomorphic from 17 years to the midtwenties. LITERATURE CITED Carter, J. E. L. 1975 The Heath-Carter Somatotype Method. Revisededition. San Diego State University, San Diego, California. Carter, J. E. L.. and W. H. Phillips 1969 Structural changes J. in exercising middle-aged males during a 2 ~ y e a period. r Appl. Physiol., 27: 787-794. Carter, J . E. L.. and R. H. Kahe 1975 Effects of stressful underwater demolition training on body structure. Med. and Science in Sports, 7: 304-308. PaEizkova, J. 1977 Body fat and physical fitness. Martinus Nijhooff, The Hague, Netherlands. Paiizkova, J., and J. E. L. Carter 1976 Influence of physical activity on stability of somatotypes in boys. Am. J. Phys. Anthrop., 44: 327-340. Ross, W. D. 1976 Metaphorical models in the study of human shape and proportionality. In: Physical Education, Sports and t h e Sciences. J. Broekhoeff, ed. Microcard Publications, Eugene, Oregon, 284-304. Ross, W. D., and B. D. Wilson 1973 A somatotype dispersion index. Res. Quart., 44: 372-374. Zuk, G. H. 1958 The plasticity of the physique from early adolescence through adulthood. J. of Genet. Psych., 92: 205-214.