Regression of body build and motor fitness in 7-19-year-old Polish youth on energy use and demographic properties of regions.

Abstract

A total of 65487 girls and 62002 boys aged from 7 to 19 years were examined in towns and villages all over Poland. Coefficients of multiple regression and percentage of explained variation in body build and motor fitness (somatic-fitness traits) of youth were calculated in relation to the variation in economic activity (as measured by electric energy use) and in demographic properties of 98 regions of Poland (urban and rural areas of 49 provinces separately). Calculations were made separately for girls 7-8, 9-10, 14-15, and 18-19 years old and for boys 7-8, 11-12, 16-17, and 18-19 years old, also for increases between these age classes in towns and villages separately. This is an extension of the analysis based on the correlation of these traits in 9.5-year-old girls and 11.5-year-old boys (Wolański et al. 1990). The regression of somatic-fitness traits on some demographic and economic properties of regions (regional factors) is most significant for rural boys, a little less significant for rural girls, and it is weakest for urban boys. The largest differences in the regression of somatic-fitness traits on regional factors between age classes were noted for rural girls, moderate for urban youth, and the smallest for rural boys. Dependence of somatic-fitness traits on regional factors increased with age. It was most clearly expressed in urban boys, and least clear in rural girls. But the strongest relationships at an age of 18 years occurred only in towns (for both sexes), whereas at an age of 9 years for rural girls and at an age of 16 years for rural boys. The analyzed traits of body build and physical fitness in youth were most strongly related to the percentage of urban population in a region, especially for urban and rural boys and rural girls. In urban girls, the most important factor was migration rate. Generally, the second most important factor influencing somatic-motor traits was electric energy use per 100 km2. The strongest effect of regional factors on motor-fitness traits was recorded for runs, standing long jump, and sit-ups, whereas running broad jump (normalized on stature) and trunk flexibility were least affected. Among body build traits, Kaup index and chest circumference were most affected, whereas arm circumference (normalized on stature twice stronger), and chest flexibility were least influenced. For example, the strongest relationship was noted between Kaup index (35.1%) in 9.5-year-old girls and regional infant death rate.