Relationship of body composition to somatotype in boys ages 7 to 12 years

The purpose of this study was to determine the association of somatotype and body composition in boys 7 to 12 years old. Somatotype was measured by two methods: Sheldon’s revised trunk index method and Heath-Carter’s anthropometric method. Body composition was estimated as fat and lean body mass using a whole-body ⁴⁰K counter. Percent fat, estimated from ⁴⁰K measurement, was most closely related to Heath and Carter’s first component, accounting for 61% of the variation (coefficient of determination, CD), and to Sheldon’s endomorphy (CD=53%). Percent fat was negatively related to Heath and Carter’s third component (CD = 42%) and Sheldon’s ectomorphy (12%) and positively related to Heath and Carter’s second component (CD = 31%). Lean body mass alone or in combination with weight and height was not significantly related to either Sheldon’s mesomorphy or Heath and Carter’s second component. Lean body mass and height together could only account for about 23% of the variation in Heath and Carter’s second component as compared to 72% when body weight, lean body mass, and height were used as predictors of somatotype. The authors conclude that endomorphy and the first component reflect body fatness to a considerable extent, but that little association between lean body mass and mesomorphy or the second component exists in children.