A valid and reliable instrument for the direct measure of perceived body size in children

Body size estimation is one means which can be used to assess the development of the concept of body-image by children. An instrument for building a model to represent the body-image of an individual child was used in this study, i.e., the Stevens' Block Figure Model (SBFM). The purposes of this study were: (a) to determine the best method of performing the task and scoring the SBFM, (b) to test the reliability of the SBFM as a direct measure of perceived body size for children, and (c) to determine the degree of validity based on the relationship of body-image measured by the SBFM with/for the theoretical constructs of age, sex, IQ, and physical activity experiences inside and outside of school.

Subjects for the study included 60, 7-, 8-, and 9-year-old children in the Tennessee area. The SBFM was the basic instrument used to assess the body size estimations of the following: (a) total height, (b) leg length, (c) trunk length, and (d) hip width. The assessment of these body segments provided the information from which to determine whether or not children could symbolically represent vertical and horizontal dimensions of their body space. To ascertain the correspondence between actual and perceived measures of body size estimation, testing occurred in two different sessions approximately seven days apart. The first test session involved making introductions and taking actual body measurements. Test session two was concerned with using the SBFM to derive the children's ascending estimations of their perceived body size.

The analyses of the data were conducted specific to the nature of eight individual subproblems. Data analyses were accomplished using correlation, regression, and multivariate techniques. Results indicated that body size perception is a complex multidimensional phenomena that acts in conjunction with other variables for 7- to 9-year-old children. The constructs of age, sex, IQ, and physical activity experience were all contributing factors to the child's ability to perceive their body size. The overall results indicate that the SBFM: (a) has high reliability (total height, r = .96; leg length, r = .91; trunk length, r = .85; hip width, r .97), and (b) has construct validity as a measure of perceived body size in 7- to 9-year-old children.